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Sample records for hybrid composite honeycomb

  1. Light-weight sandwich panel honeycomb core with hybrid carbon-glass fiber composite skin for electric vehicle application

    Science.gov (United States)

    Cahyono, Sukmaji Indro; Widodo, Angit; Anwar, Miftahul; Diharjo, Kuncoro; Triyono, Teguh; Hapid, A.; Kaleg, S.

    2016-03-01

    The carbon fiber reinforced plastic (CFRP) composite is relative high cost material in current manufacturing process of electric vehicle body structure. Sandwich panels consisting polypropylene (PP) honeycomb core with hybrid carbon-glass fiber composite skin were investigated. The aim of present paper was evaluate the flexural properties and bending rigidity of various volume fraction carbon-glass fiber composite skins with the honeycomb core. The flexural properties and cost of panels were compared to the reported values of solid hybrid Carbon/Glass FRP used for the frame body structure of electric vehicle. The finite element model of represented sandwich panel was established to characterize the flexural properties of material using homogenization technique. Finally, simplified model was employed to crashworthiness analysis for engine hood of the body electric vehicle structure. The good cost-electiveness of honeycomb core with hybrid carbon-glass fiber skin has the potential to be used as a light-weight alternative material in body electric vehicle fabricated.

  2. Super-honeycomb lattice: A hybrid fermionic and bosonic system

    CERN Document Server

    Zhong, Hua; Zhu, Yi; Zhang, Da; Li, Changbiao; Zhang, Yanpeng; Li, Fuli; Belić, Milivoj R; Xiao, Min

    2016-01-01

    We report on transport properties of the super-honeycomb lattice, the band structure of which possesses a flat band and Dirac cones, according to the tight-binding approximation. This super-honeycomb model combines the honeycomb lattice and the Lieb lattice and displays the properties of both. The super-honeycomb lattice also represents a hybrid fermionic and bosonic system, which is rarely seen in nature. By choosing the phases of input beams properly, the flat-band mode of the super-honeycomb will be excited and the input beams will exhibit a strong localization during propagation. On the other hand, if the modes of Dirac cones of the super-honeycomb lattice are excited, one will observe conical diffraction. Furthermore, if the input beam is properly chosen to excite a sublattice of the super-honeycomb lattice and the modes of Dirac cones with different pseudospins, e.g., the three-beam interference pattern, the pseudospin-mediated vortices will be observed.

  3. Hybrid composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2009-04-01

    Full Text Available effect was observed for the elongation at break of the hybrid composites. The impact strength of the hybrid composites increased with the addition of glass fibres. The tensile and impact properties of thermoplastic natural rubber reinforced short... panels made from conventional structural materials. Figure 3 illustrates the performance of cellular biocomposite panels against conventional systems used for building and residential construction, namely a pre- cast pre-stressed hollow core concrete...

  4. A honeycomb composite of mollusca shell matrix and calcium alginate.

    Science.gov (United States)

    You, Hua-jian; Li, Jin; Zhou, Chan; Liu, Bin; Zhang, Yao-guang

    2016-03-01

    A honeycomb composite is useful to carry cells for application in bone, cartilage, skin, and soft tissue regenerative therapies. To fabricate a composite, and expand the application of mollusca shells as well as improve preparing methods of calcium alginate in tissue engineering research, Anodonta woodiana shell powder was mixed with sodium alginate at varying mass ratios to obtain a gel mixture. The mixture was frozen and treated with dilute hydrochloric acid to generate a shell matrix/calcium alginate composite. Calcium carbonate served as the control. The composite was transplanted subcutaneously into rats. At 7, 14, 42, and 70 days after transplantation, frozen sections were stained with hematoxylin and eosin, followed by DAPI, β-actin, and collagen type-I immunofluorescence staining, and observed using laser confocal microscopy. The composite featured a honeycomb structure. The control and composite samples displayed significantly different mechanical properties. The water absorption rate of the composite and control group were respectively 205-496% and 417-586%. The composite (mass ratio of 5:5) showed good biological safety over a 70-day period; the subcutaneous structure of the samples was maintained and the degradation rate was lower than that of the control samples. Freezing the gel mixture afforded control over chemical reaction rates. Given these results, the composite is a promising honeycomb scaffold for tissue engineering.

  5. Fatigue fracture of fiber reinforced polymer honeycomb composite sandwich structures for gas turbine engines

    Science.gov (United States)

    Nikhamkin, Mikhail; Sazhenkov, Nikolai; Samodurov, Danil

    2017-05-01

    Fiber reinforced polymer honeycomb composite sandwich structures are commonly used in different industries. In particular, they are used in the manufacture of gas turbine engines. However, fiber reinforced polymer honeycomb composite sandwich structures often have a manufacturing flaw. In theory, such flaws due to their rapid propagation reduce the durability of fiber reinforced polymer honeycomb composite sandwich structures. In this paper, bending fatigue tests of fiber reinforced polymer honeycomb composite sandwich structures with manufacturing flaws were conducted. Comparative analysis of fatigue fracture of fiber reinforced polymer honeycomb composite sandwich specimens was conducted before and after their bending fatigue tests. The analysis was based on the internal damage X-ray observation of fiber reinforced polymer honeycomb composite sandwich specimens.

  6. Experimental and Analytical Evaluation of a Composite Honeycomb Deployable Energy Absorber

    Science.gov (United States)

    Jackson, Karen E.; Kellas, Sotiris; Horta, Lucas G.; Annett, Martin S.; Polanco, Michael A.; Littell, Justin D.; Fasanella, Edwin L.

    2011-01-01

    In 2006, the NASA Subsonic Rotary Wing Aeronautics Program sponsored the experimental and analytical evaluation of an externally deployable composite honeycomb structure that is designed to attenuate impact energy during helicopter crashes. The concept, which is designated the Deployable Energy Absorber (DEA), utilizes an expandable Kevlar honeycomb structure to dissipate kinetic energy through crushing. The DEA incorporates a unique flexible hinge design that allows the honeycomb to be packaged and stowed flat until needed for deployment. A variety of deployment options such as linear, radial, and/or hybrid methods can be used. Experimental evaluation of the DEA utilized a building block approach that included material characterization testing of its constituent, Kevlar -129 fabric/epoxy, and flexural testing of single hexagonal cells. In addition, the energy attenuation capabilities of the DEA were demonstrated through multi-cell component dynamic crush tests, and vertical drop tests of a composite fuselage section, retrofitted with DEA blocks, onto concrete, water, and soft soil. During each stage of the DEA evaluation process, finite element models of the test articles were developed and simulations were performed using the explicit, nonlinear transient dynamic finite element code, LS-DYNA. This report documents the results of the experimental evaluation that was conducted to assess the energy absorption capabilities of the DEA.

  7. Preparation and Performance of Continuous Glass Fiber Reinforced Polypropylene Composite Honeycomb Sandwich Panels

    Directory of Open Access Journals (Sweden)

    Chen Ke

    2016-01-01

    Full Text Available As the light-weight and high-strength thermoplastic composites, novel honeycomb sandwich panels were discussed in this paper: continuous glass fiber reinforced polypropylene (GF/PP laminated sheets were used as the surface and polypropylene (PP honeycomb was used as the core. The effects of honeycomb core’s height, thickness and aperture on the mechanical properties were analyzed in this paper. The composite honeycomb sandwich panels exhibited excellent bending strength at 37.6MPa and lateral pressure strength at 25.8MPa.

  8. Material Model Evaluation of a Composite Honeycomb Energy Absorber

    Science.gov (United States)

    Jackson, Karen E.; Annett, Martin S.; Fasanella, Edwin L.; Polanco, Michael A.

    2012-01-01

    A study was conducted to evaluate four different material models in predicting the dynamic crushing response of solid-element-based models of a composite honeycomb energy absorber, designated the Deployable Energy Absorber (DEA). Dynamic crush tests of three DEA components were simulated using the nonlinear, explicit transient dynamic code, LS-DYNA . In addition, a full-scale crash test of an MD-500 helicopter, retrofitted with DEA blocks, was simulated. The four material models used to represent the DEA included: *MAT_CRUSHABLE_FOAM (Mat 63), *MAT_HONEYCOMB (Mat 26), *MAT_SIMPLIFIED_RUBBER/FOAM (Mat 181), and *MAT_TRANSVERSELY_ANISOTROPIC_CRUSHABLE_FOAM (Mat 142). Test-analysis calibration metrics included simple percentage error comparisons of initial peak acceleration, sustained crush stress, and peak compaction acceleration of the DEA components. In addition, the Roadside Safety Verification and Validation Program (RSVVP) was used to assess similarities and differences between the experimental and analytical curves for the full-scale crash test.

  9. Photonic crystal fiber with a hybrid honeycomb cladding

    DEFF Research Database (Denmark)

    Mortensen, Niels Asger; Nielsen, Martin Dybendal; Folkenberg, Jacob Riis;

    2004-01-01

    be formed by manipulating the cladding region ratherthan the core region itself. Germanium-doping of the honeycomb lattice has recently been suggested for the formation of a photonic band-gap guiding silica-core and here we experimentally demonstrate how an index-guiding silica-core can be formed...

  10. Dispersion of Lamb waves in a honeycomb composite sandwich panel.

    Science.gov (United States)

    Baid, Harsh; Schaal, Christoph; Samajder, Himadri; Mal, Ajit

    2015-02-01

    Composite materials are increasingly being used in advanced aircraft and aerospace structures. Despite their many advantages, composites are often susceptible to hidden damages that may occur during manufacturing and/or service of the structure. Therefore, safe operation of composite structures requires careful monitoring of the initiation and growth of such defects. Ultrasonic methods using guided waves offer a reliable and cost effective method for defects monitoring in advanced structures due to their long propagation range and their sensitivity to defects in their propagation path. In this paper, some of the useful properties of guided Lamb type waves are investigated, using analytical, numerical and experimental methods, in an effort to provide the knowledge base required for the development of viable structural health monitoring systems for composite structures. The laboratory experiments involve a pitch-catch method in which a pair of movable transducers is placed on the outside surface of the structure for generating and recording the wave signals. The specific cases considered include an aluminum plate, a woven composite laminate and an aluminum honeycomb sandwich panel. The agreement between experimental, numerical and theoretical results are shown to be excellent in certain frequency ranges, providing a guidance for the design of effective inspection systems.

  11. Intraply Hybrid Composite Design

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1986-01-01

    Several theoretical approaches combined in program. Intraply hybrid composites investigated theoretically and experimentally at Lewis Research Center. Theories developed during investigations and corroborated by attendant experiments used to develop computer program identified as INHYD (Intraply Hybrid Composite Design). INHYD includes several composites micromechanics theories, intraply hybrid composite theories, and integrated hygrothermomechanical theory. Equations from theories used by program as appropriate for user's specific applications.

  12. Multiscale Finite-Element Modeling of Sandwich Honeycomb Composite Structures

    Directory of Open Access Journals (Sweden)

    Yu. I. Dimitrienko

    2014-01-01

    Full Text Available The paper presents a developed multi-scale model of sandwich honeycomb structures. The model allows us both to calculate effective elastic-strength characteristics of honeycomb and forced covering of sandwich, and to find a 3D stress-strain state of structures using the threedimensional elastic theory for non- homogeneous media. On the basis of finite element analysis it is shown, that under four-point bending the maximal value of bending and shear stresses in the sandwich honeycomb structures are realized in the zone of applied force and plate support. Here the local stress maxima approximately 2-3 times exceed the “engineering” theoretical plate values of bending and shear stresses in the middle of panel. It is established that at tests for fourpoint bending there is a failure of the honeycomb sandwich panels because of the local adhesion failure rather than because of the covering exfoliation off the honeycomb core in the middle of panel.

  13. Detection of disbonds in a honeycomb composite structure using guided waves

    Science.gov (United States)

    Baid, Harsh; Banerjee, Sauvik; Joshi, Shiv; Mal, Siddhartha

    2008-03-01

    Advanced composites are being used increasingly in state-of-the-art aircraft and aerospace structures. In spite of their many advantages composite materials are highly susceptible to hidden flaws that may occur at any time during the life cycle of a structure and if undetected, may cause sudden and catastrophic failure of the entire structure. An example of such a defects critical structural component is the "honeycomb composite" in which thin composite skins are bonded with adhesives to the two faces of extremely lightweight and relatively thick metallic honeycombs. These components are often used in aircraft and aerospace structures due to their high strength to weight ratio. Unfortunately, the bond between the honeycomb and the skin may degrade with age and service loads leading to separation of the load-bearing skin from the honeycomb (called "disbonds") and compromising the safety of the structure. This paper is concerned with the noninvasive detection of disbonds using ultrasonic guided waves. Laboratory experiments are carried out on a composite honeycomb specimen containing localized disbonded regions. Ultrasonic waves are launched into the specimen using a broadband PZT transducer and are detected by a distributed array of identical transducers located on the surface of the specimen. The guided wave components of the signals are shown to be very strongly influenced by the presence of a disbond. The experimentally observed results are being used to develop an autonomous scheme to locate the disbonds and to estimate their size.

  14. Development and utilization of composite honeycomb and solid laminate reference standards for aircraft inspections.

    Energy Technology Data Exchange (ETDEWEB)

    Roach, Dennis Patrick; Rackow, Kirk A.

    2004-06-01

    The FAA's Airworthiness Assurance NDI Validation Center, in conjunction with the Commercial Aircraft Composite Repair Committee, developed a set of composite reference standards to be used in NDT equipment calibration for accomplishment of damage assessment and post-repair inspection of all commercial aircraft composites. In this program, a series of NDI tests on a matrix of composite aircraft structures and prototype reference standards were completed in order to minimize the number of standards needed to carry out composite inspections on aircraft. Two tasks, related to composite laminates and non-metallic composite honeycomb configurations, were addressed. A suite of 64 honeycomb panels, representing the bounding conditions of honeycomb construction on aircraft, was inspected using a wide array of NDI techniques. An analysis of the resulting data determined the variables that play a key role in setting up NDT equipment. This has resulted in a set of minimum honeycomb NDI reference standards that include these key variables. A sequence of subsequent tests determined that this minimum honeycomb reference standard set is able to fully support inspections over the full range of honeycomb construction scenarios found on commercial aircraft. In the solid composite laminate arena, G11 Phenolic was identified as a good generic solid laminate reference standard material. Testing determined matches in key velocity and acoustic impedance properties, as well as, low attenuation relative to carbon laminates. Furthermore, comparisons of resonance testing response curves from the G11 Phenolic NDI reference standard was very similar to the resonance response curves measured on the existing carbon and fiberglass laminates. NDI data shows that this material should work for both pulse-echo (velocity-based) and resonance (acoustic impedance-based) inspections.

  15. Application of sandwich honeycomb carbon/glass fiber-honeycomb composite in the floor component of electric car

    Science.gov (United States)

    Sukmaji, I. C.; Wijang, W. R.; Andri, S.; Bambang, K.; Teguh, T.

    2017-01-01

    Nowadays composite is a superior material used in automotive component due to its outstanding mechanical behavior. The sandwich polypropylene honeycomb core with carbon/glass fiber composite skin (SHCG) as based material in a floor component of electric car application is investigated in the present research. In sandwich structure form, it can absorb noise better compare with the conventional material [1]. Also in present paper, Finite Element Analysis (FEA) of SHCG as based material for floor component of the electric car is analyzed. The composite sandwich is contained with a layer uniform carbon fiber and mixing non-uniform carbon-glass fiber in upper and lower skin. Between skins of SHCG are core polypropylene honeycomb that it have good flexibility to form following dies profile. The variables of volume fraction ratio of carbon/glass fiber in SHCG skin are 20/80%, 30/70%, and 50/50%. The specimen of SHCG is tested using the universal testing machine by three points bending method refers to ASTM C393 and ASTM C365. The cross point between tensile strength to the volume fraction the mixing carbon/glass line and ratio cost line are the searched material with good mechanical performance and reasonable cost. The point is 30/70 volume fraction of carbon/glass fiber. The result of the testing experiment is become input properties of model structure sandwich in FEA simulation. FEA simulation approach is conducted to find critical strength and factor of complex safety geometry against varied distributed passenger loads of a floor component the electric car. The passenger loads variable are 80, 100, 150, 200, 250 and 300 kg.

  16. Probability of Detection Study on Impact Damage to Honeycomb Composite Structure using Thermographic Inspection

    Science.gov (United States)

    Hodge, Andrew J.; Walker, James L., II

    2008-01-01

    A probability of detection study was performed for the detection of impact damage using flash heating infrared thermography on a full scale honeycomb composite structure. The honeycomb structure was an intertank structure from a previous NASA technology demonstration program. The intertank was fabricated from IM7/8552 carbon fiber/epoxy facesheets and aluminum honeycomb core. The intertank was impacted in multiple locations with a range of impact energies utilizing a spherical indenter. In a single blind study, the intertank was inspected with thermography before and after impact damage was incurred. Following thermographic inspection several impact sites were sectioned from the intertank and cross-sectioned for microscopic comparisons of NDE detection and actual damage incurred. The study concluded that thermographic inspection was a good method of detecting delamination damage incurred by impact. The 90/95 confidence level on the probability of detection was close to the impact energy that delaminations were first observed through cross-sectional analysis.

  17. Morphing hybrid honeycomb (MOHYCOMB) with in situ Poisson’s ratio modulation

    Science.gov (United States)

    Heath, Callum J. C.; Neville, Robin M.; Scarpa, Fabrizio; Bond, Ian P.; Potter, Kevin D.

    2016-08-01

    Electrostatic adhesion can be used as a means of reversible attachment. Through application of high voltage (~2 kV) across closely spaced parallel plate electrodes, significant shear stresses (11 kPa) can be generated. The highest levels of electrostatic holding force can be achieved through close contact of connection surfaces; this is facilitated by flexible electrodes which can conform to reduce air gaps. Cellular structures are comprised of thin walled elements, making them ideal host structures for electrostatic adhesive elements. The reversible adhesion provides control of the internal connectivity of the cellular structure, and determines the effective cell geometry. This would offer variable stiffness and control of the effective Poisson’s ratio of the global cellular array. Using copper-polyimide thin film laminates and PVDF thin film dielectrics, double lap shear electrostatic adhesive elements have been introduced to a cellular geometry. By activating different groups of reversible adhesive interfaces, the cellular array can assume four different cell configurations. A maximum stiffness modulation of 450% between the ‘All off’ and ‘All on’ cell morphologies has been demonstrated. This structure is also capable of in situ effective Poisson’s ratio variations, with the ability to switch between values of -0.45 and 0.54. Such a structure offers the potential for tuneable vibration absorption (due to its variable stiffness properties), or as a smart honeycomb with controllable curvature and is termed morphing hybrid honeycomb.

  18. Fracture Testing of Honeycomb Core Sandwich Composites Using the DCB-UBM Test

    DEFF Research Database (Denmark)

    Saseendran, Vishnu; Berggreen, Christian; Carlsson, Leif A.

    2015-01-01

    of the face/core interface. In this paper, a novel test-rig exploiting the double cantilever beam-uneven bending moments (DCB-UBM) concept is used to determine the fracture toughness of aircraft type honeycomb core sandwich composites as a function of the phase angle (mode-mixity), within the framework......Face/core debonds in sandwich structures cause loss of integrity of sandwich structures. The debond problem in honeycomb core sandwich composites has not been widely studied. A suitable fracture approach coupled with experimental validation is paramount to determine the fracture resistance...... of Linear Elastic Fracture Mechanics (LEFM). The Double Cantilever Beam subjected to Uneven Bending Moments (DCB-UBM) test set-up, which was introduced by Sørensen.et.al [1], circumvents any dependency of the pre-crack length in calculation of Gc. The new test setup is based on rotary actuators which...

  19. Simulating the Response of a Composite Honeycomb Energy Absorber. Part 2; Full-Scale Impact Testing

    Science.gov (United States)

    Fasanella, Edwin L.; Annett, Martin S.; Jackson, Karen E.; Polanco, Michael A.

    2012-01-01

    NASA has sponsored research to evaluate an externally deployable composite honeycomb designed to attenuate loads in the event of a helicopter crash. The concept, designated the Deployable Energy Absorber (DEA), is an expandable Kevlar(Registered TradeMark) honeycomb. The DEA has a flexible hinge that allows the honeycomb to be stowed collapsed until needed during an emergency. Evaluation of the DEA began with material characterization of the Kevlar(Registered TradeMark)-129 fabric/epoxy, and ended with a full-scale crash test of a retrofitted MD-500 helicopter. During each evaluation phase, finite element models of the test articles were developed and simulations were performed using the dynamic finite element code, LS-DYNA(Registered TradeMark). The paper will focus on simulations of two full-scale impact tests involving the DEA, a mass-simulator and a full-scale crash of an instrumented MD-500 helicopter. Isotropic (MAT24) and composite (MAT58) material models, which were assigned to DEA shell elements, were compared. Based on simulations results, the MAT58 model showed better agreement with test.

  20. Hybrid silicon honeycomb/organic solar cells with enhanced efficiency using surface etching

    Science.gov (United States)

    Liu, Ruiyuan; Sun, Teng; Liu, Jiawei; Wu, Shan; Sun, Baoquan

    2016-06-01

    Silicon (Si) nanostructure-based photovoltaic devices are attractive for their excellent optical and electrical performance, but show lower efficiency than their planar counterparts due to the increased surface recombination associated with the high surface area and roughness. Here, we demonstrate an efficiency enhancement for hybrid nanostructured Si/polymer solar cells based on a novel Si honeycomb (SiHC) structure using a simple etching method. SiHC structures are fabricated using a combination of nanosphere lithography and plasma treatment followed by a wet chemical post-etching. SiHC has shown superior light-trapping ability in comparison with the other Si nanostructures, along with a robust structure. Anisotropic tetramethylammonium hydroxide etching not only tunes the final surface morphologies of the nanostructures, but also reduces the surface roughness leading to a lower recombination rate in the hybrid solar cells. The suppressed recombination loss, benefiting from the reduced surface-to-volume ratio and roughness, has resulted in a high open-circuit voltage of 600 mV, a short-circuit current of 31.46 mA cm-2 due to the light-trapping ability of the SiHCs, and yields a power conversion efficiency of 12.79% without any other device structure optimization.

  1. Hybrid silicon honeycomb/organic solar cells with enhanced efficiency using surface etching.

    Science.gov (United States)

    Liu, Ruiyuan; Sun, Teng; Liu, Jiawei; Wu, Shan; Sun, Baoquan

    2016-06-24

    Silicon (Si) nanostructure-based photovoltaic devices are attractive for their excellent optical and electrical performance, but show lower efficiency than their planar counterparts due to the increased surface recombination associated with the high surface area and roughness. Here, we demonstrate an efficiency enhancement for hybrid nanostructured Si/polymer solar cells based on a novel Si honeycomb (SiHC) structure using a simple etching method. SiHC structures are fabricated using a combination of nanosphere lithography and plasma treatment followed by a wet chemical post-etching. SiHC has shown superior light-trapping ability in comparison with the other Si nanostructures, along with a robust structure. Anisotropic tetramethylammonium hydroxide etching not only tunes the final surface morphologies of the nanostructures, but also reduces the surface roughness leading to a lower recombination rate in the hybrid solar cells. The suppressed recombination loss, benefiting from the reduced surface-to-volume ratio and roughness, has resulted in a high open-circuit voltage of 600 mV, a short-circuit current of 31.46 mA cm(-2) due to the light-trapping ability of the SiHCs, and yields a power conversion efficiency of 12.79% without any other device structure optimization.

  2. Hybrid Aluminum and Natural Fiber Composite Structure for Crash Safety Improvement

    Science.gov (United States)

    Helaili, S.; Chafra, M.; Chevalier, Y.

    There is a growing interest on pedestrian's protection in automotive safety standards. Pedestrians head impact is one of the most important tests. In this paper, a hybrid composite structure made from natural fiber and aluminum, which improve the head protection when impact is taken place, is presented. The structure is made from a honeycomb composite made from unidirectional and woven composites and a thin aluminum layer. A head impact model is developed. The number of hexagonal layers is fixed and the thickness of the aluminum layer of the honeycomb structure is varied. The specific absorption energy is then calculated.

  3. From Fragile to Resilient Insulation: Synthesis and Characterization of Aramid-Honeycomb Reinforced Silica Aerogel Composite Materials

    Directory of Open Access Journals (Sweden)

    Marina Schwan

    2015-12-01

    Full Text Available The production of a new composite material embedding aramid honeycomb materials into nano-porous silica aerogels is studied. Our aim is to improve the poor mechanical strength of silica aerogels by aramid honeycombs without losing the amazing properties of the aerogels like little density and low thermal conductivity. The composite materials were prepared using two formulations of silica aerogels in combination with aramid honeycomb materials of different cell sizes. The silica aerogels are prepared using silicon alkoxides methyltrimethoxysilane and tetraethylorthosilicate as precursors in a two-step acid–base sol–gel process. Shortly in advance of the gelation point, the aramid honeycombs were fluted by the sol, gelation occurred and, after the aging process, the gel bodies were supercritically dried. The properties of the received composite materials are satisfying. Even the thermal conductivities and the densities are a bit higher than for pure aerogels. Most importantly, the mechanical strength is improved by a factor of 2.3 compared to aramid honeycomb materials and by a factor of 10 compared to the two silica aerogels themselves. The composite materials have a good prospective to be used as an impressive insulation material.

  4. Optimized Non-Obstructive Particle Damping (NOPD) Treatment for Composite Honeycomb Structures

    Science.gov (United States)

    Panossian, H.

    2008-01-01

    Non-Obstructive Particle Damping (NOPD) technology is a passive vibration damping approach whereby metallic or non-metallic particles in spherical or irregular shapes, of heavy or light consistency, and even liquid particles are placed inside cavities or attached to structures by an appropriate means at strategic locations, to absorb vibration energy. The objective of the work described herein is the development of a design optimization procedure and discussion of test results for such a NOPD treatment on honeycomb (HC) composite structures, based on finite element modeling (FEM) analyses, optimization and tests. Modeling and predictions were performed and tests were carried out to correlate the test data with the FEM. The optimization procedure consisted of defining a global objective function, using finite difference methods, to determine the optimal values of the design variables through quadratic linear programming. The optimization process was carried out by targeting the highest dynamic displacements of several vibration modes of the structure and finding an optimal treatment configuration that will minimize them. An optimal design was thus derived and laboratory tests were conducted to evaluate its performance under different vibration environments. Three honeycomb composite beams, with Nomex core and aluminum face sheets, empty (untreated), uniformly treated with NOPD, and optimally treated with NOPD, according to the analytically predicted optimal design configuration, were tested in the laboratory. It is shown that the beam with optimal treatment has the lowest response amplitude. Described below are results of modal vibration tests and FEM analyses from predictions of the modal characteristics of honeycomb beams under zero, 50% uniform treatment and an optimal NOPD treatment design configuration and verification with test data.

  5. Vibroacoustic flexural properties of symmetric honeycomb sandwich panels with composite faces

    Science.gov (United States)

    Guillaumie, Laurent

    2015-05-01

    The vibroacoustic bending properties of honeycomb sandwich panels with composite faces are studied from the wavenumber modulus to the mechanical impedance, passing through the modal density. Numerical results extracted from finite element software computations are compared with analytical results. In both cases, the homogenization method is used to calculate the global properties of the sandwich panel. Since faces are made of composite material, the classical laminate theory serves as reference. With particular conditions used in the application for symmetric panels, the original orthotropic mechanical properties can be reduced simply to three parameters commonly used in vibroacoustic characterizations. These three parameters are the mass per unit area, the bending rigidity and the out-of-plane shear rigidity. They simultaneously govern the wavenumber modulus, the modal frequencies, the modal density and the mechanical impedance. For all of these vibroacoustic characterizations, a special frequency called the transition frequency separates two domains. In the first domain, below the transition frequency or for low frequencies, the orthotropic sandwich panel has a classical isotropic plate behavior. In the second domain, above the transition frequency or for high frequencies, the out-of-plane shear rigidity is very significant and changes the behavior. However, the results discussed are only valid up to a certain frequency which is determined by the thickness and out-of-plane shear stiffness of the honeycomb core, the thickness and the bending stiffness of the laminated face sheets and then the mass per unit area and bending stiffness of the total sandwich structure. All these parameters influence the final choice of model and simplifications presented. Experimental measurements of the bending wavenumber modulus and modal frequencies for our own application were carried out. In the vibroacoustic domain, the critical frequency is also an important frequency. It again

  6. Automated laser-based barely visible impact damage detection in honeycomb sandwich composite structures

    Energy Technology Data Exchange (ETDEWEB)

    Girolamo, D., E-mail: dgirola@ncsu.edu; Yuan, F. G. [National Institute of Aerospace, Integrated Structural Health Management Laboratory, Hampton, VA 23666 and North Carolina State University, Department of Mechanical and Aerospace Engineering, Raleigh, NC 27695 (United States); Girolamo, L. [North Carolina State University, Department of Mechanical and Aerospace Engineering, Raleigh, NC 27695 (United States)

    2015-03-31

    Nondestructive evaluation (NDE) for detection and quantification of damage in composite materials is fundamental in the assessment of the overall structural integrity of modern aerospace systems. Conventional NDE systems have been extensively used to detect the location and size of damages by propagating ultrasonic waves normal to the surface. However they usually require physical contact with the structure and are time consuming and labor intensive. An automated, contactless laser ultrasonic imaging system for barely visible impact damage (BVID) detection in advanced composite structures has been developed to overcome these limitations. Lamb waves are generated by a Q-switched Nd:YAG laser, raster scanned by a set of galvano-mirrors over the damaged area. The out-of-plane vibrations are measured through a laser Doppler Vibrometer (LDV) that is stationary at a point on the corner of the grid. The ultrasonic wave field of the scanned area is reconstructed in polar coordinates and analyzed for high resolution characterization of impact damage in the composite honeycomb panel. Two methodologies are used for ultrasonic wave-field analysis: scattered wave field analysis (SWA) and standing wave energy analysis (SWEA) in the frequency domain. The SWA is employed for processing the wave field and estimate spatially dependent wavenumber values, related to discontinuities in the structural domain. The SWEA algorithm extracts standing waves trapped within damaged areas and, by studying the spectrum of the standing wave field, returns high fidelity damage imaging. While the SWA can be used to locate the impact damage in the honeycomb panel, the SWEA produces damage images in good agreement with X-ray computed tomographic (X-ray CT) scans. The results obtained prove that the laser-based nondestructive system is an effective alternative to overcome limitations of conventional NDI technologies.

  7. Honeycomb-structured porous poly(3,4-ethylenedioxythiophene) composite layers on a gold electrode

    Energy Technology Data Exchange (ETDEWEB)

    Krzyczmonik, Paweł, E-mail: pawel@chemia.uni.lodz.pl [Department of Inorganic and Analytical Chemistry, Team of Electroanalysis and Electrochemistry, University of Lodz, Tamka 12, 91-403 Lodz (Poland); Socha, Ewelina; Skrzypek, Sławomira [Department of Inorganic and Analytical Chemistry, Team of Electroanalysis and Electrochemistry, University of Lodz, Tamka 12, 91-403 Lodz (Poland); Soliwoda, Katarzyna; Celichowski, Grzegorz; Grobelny, Jarosław [Department of Materials Technology and Chemistry, University of Lodz, Pomorska 163, 90-236 Lodz (Poland)

    2014-08-28

    Three microstructured electrodes modified with poly(3,4-ethylenedioxythiophene) (PEDOT) were obtained. One electrode was modified with PEDOT doped with poly(4-lithium styrenesulfonic acid) (PSSLi), the second one with a PEDOT + polyacrylic acid composite doped with PSSLi, and the third one with a PEDOT + anthranilic acid composite doped with poly(4-styrenesulfonic acid). The three electrodes were prepared using templates of polystyrene latex spheres (PS). The templates were deposited on the electrode using our dip-coating-like technique that we developed by optimizing key parameters, such as PS and sodium dodecyl sulfate concentration, angle of inclination, and decantation rate. The structure of the templates was verified by optical microscopy. A conducting polymer layer was obtained by electropolymerization from appropriate monomer solutions. In the final stage, the template was dissolved in toluene and the morphology of the resulting honeycomb-structure was examined by atomic force microscopy and scanning electron microscopy methods. The electrochemical properties of the electrodes were tested by cyclic voltammetry and electrochemical impedance spectroscopy. - Highlights: • We developed microstructured electrodes based on conducting composites. • We obtained three composites with PEDOT, polyacrylic acid and anthranilic acid. • All structures were obtained on a polystyrene template via electropolymerization. • SDS surfactant plays a key role during template deposition process.

  8. Evaluation of Composite Honeycomb Sandwich Panels Under Compressive Loads at Elevated Temperatures

    Science.gov (United States)

    Walker, Sandra P.

    1998-01-01

    Fourteen composite honeycomb sandwich panels were tested to failure under compressive loading. The test specimens included panels with both 8 and 24-ply graphite-bismaleimide composite facesheets and both titanium and graphite-polyimide core materials. The panels were designed to have the load introduced through fasteners attached to pairs of steel angles on the ends of the panels to simulate double shear splice joints. The unloaded edges were unconstrained. Test temperatures included room temperature, 250F, and 300F. For the room and 250F temperature tests, the 24-ply specimen failure strains were close to the unnotched allowable strain values and failure loads were well above the design loads. However, failure strains much lower than the unnotched allowable strain values, and failure loads below the design loads were observed with several of the 8-ply specimens. For each individual test temperature, large variations in the failure strains and loads were observed for the 8-ply specimens. Dramatic decreases in the failure strains and loads were observed for the 24-ply specimens as the test temperature was increased from 250F to 300F. All 8-ply specimens appeared to have failed in a facesheet strength failure mode for all test temperatures. The 24-ply specimens displayed appreciably greater amounts of bending prior to failure than the 8-ply specimens, and panel buckling occurred prior to facesheet strength failure for the 24-ply room and 250F temperature tests.

  9. Simulating the Response of a Composite Honeycomb Energy Absorber. Part 1; Dynamic Crushing of Components and Multi-Terrain Impacts

    Science.gov (United States)

    Jackson, Karen E.; Fasanella, Edwin L.; Polanco, Michael A.

    2012-01-01

    This paper describes the experimental and analytical evaluation of an externally deployable composite honeycomb structure that is designed to attenuate impact energy during helicopter crashes. The concept, designated the Deployable Energy Absorber (DEA), utilizes an expandable Kevlar (Registered Trademark) honeycomb to dissipate kinetic energy through crushing. The DEA incorporates a unique flexible hinge design that allows the honeycomb to be packaged and stowed until needed for deployment. Experimental evaluation of the DEA included dynamic crush tests of multi-cell components and vertical drop tests of a composite fuselage section, retrofitted with DEA blocks, onto multi-terrain. Finite element models of the test articles were developed and simulations were performed using the transient dynamic code, LSDYNA (Registered Trademark). In each simulation, the DEA was represented using shell elements assigned two different material properties: Mat 24, an isotropic piecewise linear plasticity model, and Mat 58, a continuum damage mechanics model used to represent laminated composite fabrics. DEA model development and test-analysis comparisons are presented.

  10. Buckling Analysis of a Honeycomb-Core Composite Cylinder with Initial Geometric Imperfections

    Science.gov (United States)

    Cha, Gene; Schultz, Marc R.

    2013-01-01

    Thin-walled cylindrical shell structures often have buckling as the critical failure mode, and the buckling of such structures can be very sensitive to small geometric imperfections. The buckling analyses of an 8-ft-diameter, 10-ft-long honeycomb-core composite cylinder loaded in pure axial compression is discussed in this document. Two loading configurations are considered configuration 1 uses simple end conditions, and configuration 2 includes additional structure that may more closely approximate experimental loading conditions. Linear eigenvalue buckling analyses and nonlinear analyses with and without initial geometric imperfections were performed on both configurations. The initial imperfections were introduced in the shell by applying a radial load at the midlength of the cylinder to form a single inward dimple. The critical bifurcation buckling loads are predicted to be 924,190 lb and 924,020 lb for configurations 1 and 2, respectively. Nonlinear critical buckling loads of 918,750 lb and 954,900 lb were predicted for geometrically perfect configurations 1 and 2, respectively. Lower-bound critical buckling loads for configurations 1 and 2 with radial perturbations were found to be 33% and 36% lower, respectively, than the unperturbed critical loads. The inclusion of the load introduction cylinders in configuration 2 increased the maximum bending-boundary-layer rotation up to 11%.

  11. Guided wave propagation in a honeycomb composite sandwich structure in presence of a high density core.

    Science.gov (United States)

    Sikdar, Shirsendu; Banerjee, Sauvik

    2016-09-01

    A coordinated theoretical, numerical and experimental study is carried out in an effort to interpret the characteristics of propagating guided Lamb wave modes in presence of a high-density (HD) core region in a honeycomb composite sandwich structure (HCSS). Initially, a two-dimensional (2D) semi-analytical model based on the global matrix method is used to study the response and dispersion characteristics of the HCSS with a soft core. Due to the complex structural characteristics, the study of guided wave (GW) propagation in HCSS with HD-core region inherently poses many challenges. Therefore, a numerical simulation of GW propagation in the HCSS with and without the HD-core region is carried out, using surface-bonded piezoelectric wafer transducer (PWT) network. From the numerical results, it is observed that the presence of HD-core significantly decreases both the group velocity and the amplitude of the received GW signal. Laboratory experiments are then conducted in order to verify the theoretical and numerical results. A good agreement between the theoretical, numerical and experimental results is observed in all the cases studied. An extensive parametric study is also carried out for a range of HD-core sizes and densities in order to study the effect due to the change in size and density of the HD zone on the characteristics of propagating GW modes. It is found that the amplitudes and group velocities of the GW modes decrease with the increase in HD-core width and density.

  12. Intercalated hybrid graphite fiber composite

    Science.gov (United States)

    Gaier, James R. (Inventor)

    1993-01-01

    The invention is directed to a highly conductive lightweight hybrid material and methods of producing the same. The hybrid composite is obtained by weaving strands of a high strength carbon or graphite fiber into a fabric-like structure, depositing a layer of carbon onto the structure, heat treating the structure to graphitize the carbon layer, and intercalating the graphitic carbon layer structure. A laminate composite material useful for protection against lightning strikes comprises at least one layer of the hybrid material over at least one layer of high strength carbon or graphite fibers. The composite material of the present invention is compatible with matrix compounds, has a coefficient of thermal expansion which is the same as underlying fiber layers, and is resistant to galvanic corrosion in addition to being highly conductive. These materials are useful in the aerospace industry, in particular as lightning strike protection for airplanes.

  13. Hybrid composite laminate structures

    Science.gov (United States)

    Chamis, C. C.; Lark, R. F. (Inventor)

    1977-01-01

    An invention which relates to laminate structures and specifically to essentially anisotropic fiber composite laminates is described. Metal foils are selectively disposed within the laminate to produce increased resistance to high velocity impact, fracture, surface erosion, and other stresses within the laminate.

  14. Hybrid Simulation of Composite Structures

    DEFF Research Database (Denmark)

    Høgh, Jacob Herold

    Hybrid simulation is a substructural method combining a numerical simulation with a physical experiment. A structure is thereby simulated under the assumption that a substructure’s response is well known and easily modelled while a given substructure is studied more accurately in a physical...... of freedom. In this dissertation the main focus is to develop hybrid simulation for composite structures e.g. wind turbine blades where the boundary between the numerical model and the physical experiment is continues i.e. in principal infinite amount of degrees of freedom. This highly complicates...

  15. Hybrid and hierarchical composite materials

    CERN Document Server

    Kim, Chang-Soo; Sano, Tomoko

    2015-01-01

    This book addresses a broad spectrum of areas in both hybrid materials and hierarchical composites, including recent development of processing technologies, structural designs, modern computer simulation techniques, and the relationships between the processing-structure-property-performance. Each topic is introduced at length with numerous  and detailed examples and over 150 illustrations.   In addition, the authors present a method of categorizing these materials, so that representative examples of all material classes are discussed.

  16. Shape Memory Composite Hybrid Hinge

    Science.gov (United States)

    Fang, Houfei; Im, Eastwood; Lin, John; Scarborough, Stephen

    2012-01-01

    There are two conventional types of hinges for in-space deployment applications. The first type is mechanically deploying hinges. A typical mechanically deploying hinge is usually composed of several tens of components. It is complicated, heavy, and bulky. More components imply higher deployment failure probability. Due to the existence of relatively moving components among a mechanically deploying hinge, it unavoidably has microdynamic problems. The second type of conventional hinge relies on strain energy for deployment. A tape-spring hinge is a typical strain energy hinge. A fundamental problem of a strain energy hinge is that its deployment dynamic is uncontrollable. Usually, its deployment is associated with a large impact, which is unacceptable for many space applications. Some damping technologies have been experimented with to reduce the impact, but they increased the risks of an unsuccessful deployment. Coalescing strain energy components with shape memory composite (SMC) components to form a hybrid hinge is the solution. SMCs are well suited for deployable structures. A SMC is created from a high-performance fiber and a shape memory polymer resin. When the resin is heated to above its glass transition temperature, the composite becomes flexible and can be folded or packed. Once cooled to below the glass transition temperature, the composite remains in the packed state. When the structure is ready to be deployed, the SMC component is reheated to above the glass transition temperature, and it returns to its as-fabricated shape. A hybrid hinge is composed of two strain energy flanges (also called tape-springs) and one SMC tube. Two folding lines are placed on the SMC tube to avoid excessive strain on the SMC during folding. Two adapters are used to connect the hybrid hinge to its adjacent structural components. While the SMC tube is heated to above its glass transition temperature, a hybrid hinge can be folded and stays at folded status after the temperature

  17. Hybrid Composites for LH2 Fuel Tank Structure

    Science.gov (United States)

    Grimsley, Brian W.; Cano, Roberto J.; Johnston, Norman J.; Loos, Alfred C.; McMahon, William M.

    2001-01-01

    The application of lightweight carbon fiber reinforced plastics (CFRP) as structure for cryogenic fuel tanks is critical to the success of the next generation of Reusable Launch Vehicles (RLV). The recent failure of the X-33 composite fuel tank occurred in part due to microcracking of the polymer matrix, which allowed cryogen to permeate through the inner skin to the honeycomb core. As part of an approach to solve these problems, NASA Langley Research Center (LaRC) and Marshall Space Flight Center (MSFC) are working to develop and investigate polymer films that will act as a barrier to the permeation of LH2 through the composite laminate. In this study two commercially available films and eleven novel LaRC films were tested in an existing cryogenics laboratory at MSFC to determine the permeance of argon at room temperature. Several of these films were introduced as a layer in the composite to form an interleaved, or hybrid, composite to determine the effects on permeability. In addition, the effects of the interleaved layer thickness, number, and location on the mechanical properties of the composite laminate were investigated. In this initial screening process, several of the films were found to exhibit lower permeability to argon than the composite panels tested.

  18. Detecting the honeycomb sandwich composite material's moisture impregnating defects by using infrared thermography technique

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Koo Ahn; Choi, Man Yong; Park, Jeong Hak; Choi, Won Jae [Safety Measurement Center, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Park, Hee Sang [R and D, Korea Research Institute of Smart Material and Structures System Association, Daejeon (Korea, Republic of)

    2017-04-15

    Many composite materials are used in the aerospace industry because of their excellent mechanical properties. However, the nature of aviation exposes these materials to high temperature and high moisture conditions depending on climate, location, and altitude. Therefore, the molecular arrangement chemical properties, and mechanical properties of composite materials can be changed under these conditions. As a result, surface disruptions and cracks can be created. Consequently, moisture-impregnating defects can be induced due to the crack and delamination of composite materials as they are repeatedly exposed to moisture absorption moisture release, fatigue environment, temperature changes, and fluid pressure changes. This study evaluates the possibility of detecting the moisture-impregnating defects of CFRP and GFRP honeycomb structure sandwich composite materials, which are the composite materials in the aircraft structure, by using an active infrared thermography technology among non-destructive testing methods. In all experiments, it was possible to distinguish the area and a number of CFRP composite materials more clearly than those of GFRP composite material. The highest detection rate was observed in the heating duration of 50 mHz and the low detection rate was at the heating duration of over 500 mHz. The reflection method showed a higher detection rate than the transmission method.

  19. Computer code for intraply hybrid composite design

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1981-01-01

    A computer program has been developed and is described herein for intraply hybrid composite design (INHYD). The program includes several composite micromechanics theories, intraply hybrid composite theories and a hygrothermomechanical theory. These theories provide INHYD with considerable flexibility and capability which the user can exercise through several available options. Key features and capabilities of INHYD are illustrated through selected samples.

  20. Hybrid Composite Cryogenic Tank Structure

    Science.gov (United States)

    DeLay, Thomas

    2011-01-01

    A hybrid lightweight composite tank has been created using specially designed materials and manufacturing processes. The tank is produced by using a hybrid structure consisting of at least two reinforced composite material systems. The inner composite layer comprises a distinct fiber and resin matrix suitable for cryogenic use that is a braided-sleeve (and/or a filamentwound layer) aramid fiber preform that is placed on a removable mandrel (outfitted with metallic end fittings) and is infused (vacuum-assisted resin transfer molded) with a polyurethane resin matrix with a high ductility at low temperatures. This inner layer is allowed to cure and is encapsulated with a filamentwound outer composite layer of a distinct fiber resin system. Both inner and outer layer are in intimate contact, and can also be cured at the same time. The outer layer is a material that performs well for low temperature pressure vessels, and it can rely on the inner layer to act as a liner to contain the fluids. The outer layer can be a variety of materials, but the best embodiment may be the use of a continuous tow of carbon fiber (T-1000 carbon, or others), or other high-strength fibers combined with a high ductility epoxy resin matrix, or a polyurethane matrix, which performs well at low temperatures. After curing, the mandrel can be removed from the outer layer. While the hybrid structure is not limited to two particular materials, a preferred version of the tank has been demonstrated on an actual test tank article cycled at high pressures with liquid nitrogen and liquid hydrogen, and the best version is an inner layer of PBO (poly-pphenylenebenzobisoxazole) fibers with a polyurethane matrix and an outer layer of T-1000 carbon with a high elongation epoxy matrix suitable for cryogenic temperatures. A polyurethane matrix has also been used for the outer layer. The construction method is ideal because the fiber and resin of the inner layer has a high strain to failure at cryogenic

  1. Flexural performance of woven hybrid composites

    Science.gov (United States)

    Maslinda, A. B.; Majid, M. S. Abdul; Dan-mallam, Y.; Mazawati, M.

    2016-07-01

    This paper describes the experimental investigation of the flexural performance of natural fiber reinforced polymer composites. Hybrid composites consist of interwoven kenaf/jute and kenaf/hemp fibers was prepared by infusion process using epoxy as polymer matrix. Woven kenaf, jute and hemp composites were also prepared for comparison. Both woven and hybrid composites were subjected to three point flexural test. From the result, bending resistance of hybrid kenaf/jute and kenaf/hemp composites was higher compared to their individual fiber. Hybridization with high strength fiber such as kenaf enhanced the capability of jute and hemp fibers to withstand bending load. Interlocking between yarns in woven fabric make pull out fibers nearly impossible and increase the flexural performance of the hybrid composites.

  2. Properties of Cf/PI Honeycomb Sandwich Composites%Cf/PI蜂窝夹层结构性能

    Institute of Scientific and Technical Information of China (English)

    赵伟栋; 潘玲英; 蒋文革; 王会平

    2011-01-01

    为了提高蜂窝夹层结构的耐热性和高温力学性能,采用石英灯和力学性能测试的方法进行了相关性能测试.弯曲性能测试结果表明,UT500/KH370蜂窝夹层面板的弯曲强度400℃保持率为58%,弯曲模量保持率为85%,层间剪切强度保持率为57%;石英灯静态隔热试验结果表明,冷壁热流为300 kW/m2的条件下,高度为29mm的蜂窝夹层板的背温为320℃;冷壁热流为168 kW/m2的条件下,背温为296℃.%In order to enhance the heat resistant and mechanical properties of honeycomb sandwich at high temperature , the test of mechanical properties and heat insulation properties with static quartz lamp are carried out. The result shows that the retaining rate of flexural strength,moduli and interlaminate of panel are 58% ,85% and 57% .respectively. After the sample heated by static quartz lamp,with 300 kW/m2 and 168 kW/m2 heat flux for 180 s.the back temperature of honeycomb structural composites are 320t! And 2961, respectively.

  3. Cellular Energy Absorbing TRIP-Steel/Mg-PSZ Composite: Honeycomb Structures Fabricated by a New Extrusion Powder Technology

    Directory of Open Access Journals (Sweden)

    Ulrich Martin

    2010-01-01

    Full Text Available Lightweight linear cellular composite materials on basis of austenite stainless TRIP- (TRansformation Induced Plasticity- steel as matrix with reinforcements of MgO partially stabilized zirconia (Mg-PSZ are described. Two-dimensional cellular materials for structural applications are conventionally produced by sheet expansion or corrugation processes. The presented composites are fabricated by a modified ceramic extrusion powder technology. Characterization of the microstructure in as-received and deformed conditions was carried out by optical and scanning electron microscopy. Magnetic balance measurements and electron backscatter diffraction (EBSD were used to identify the deformation-induced martensite evolution in the cell wall material. The honeycomb composite samples exhibit an increased strain hardening up to a certain engineering compressive strain and an extraordinary high specific energy absorption per unit mass and unit volume, respectively. Based on improved property-to-weight ratio such linear cellular structures will be of interest as crash absorbers or stiffened core materials for aerospace, railway, or automotive applications.

  4. Toward automatic evaluation of defect detectability in infrared images of composites and honeycomb structures

    Science.gov (United States)

    Florez-Ospina, Juan F.; Benitez-Restrepo, H. D.

    2015-07-01

    Non-destructive testing (NDT) refers to inspection methods employed to assess a material specimen without impairing its future usefulness. An important type of these methods is infrared (IR) for NDT (IRNDT), which employs the heat emitted by bodies/objects to rapidly and noninvasively inspect wide surfaces and to find specific defects such as delaminations, cracks, voids, and discontinuities in materials. Current advancements in sensor technology for IRNDT generate great amounts of image sequences. These data require further processing to determine the integrity of objects. Processing techniques for IRNDT data implicitly looks for defect visibility enhancement. Commonly, IRNDT community employs signal to noise ratio (SNR) to measure defect visibility. Nonetheless, current applications of SNR are local, thereby overseeing spatial information, and depend on a-priori knowledge of defect's location. In this paper, we present a general framework to assess defect detectability based on SNR maps derived from processed IR images. The joint use of image segmentation procedures along with algorithms for filling regions of interest (ROI) estimates a reference background to compute SNR maps. Our main contributions are: (i) a method to compute SNR maps that takes into account spatial variation and are independent of a-priori knowledge of defect location in the sample, (ii) spatial background analysis in processed images, and (iii) semi-automatic calculation of segmentation algorithm parameters. We test our approach in carbon fiber and honeycomb samples with complex geometries and defects with different sizes and depths.

  5. Mechanical property characterization of intraply hybrid composites

    Science.gov (United States)

    Chamis, C. C.; Lark, R. F.; Sinclair, J. H.

    1979-01-01

    An investigation of the mechanical properties of intraply hybrids made from graphite fiber/epoxy matrix hybridized with secondary S-glass or Kevlar 49 fiber composites is presented. The specimen stress-strain behavior was determined, showing that mechanical properties of intraply hybrid composites can be measured with available methods such as the ten-degree off-axis test for intralaminar shear, and conventional tests for tensile, flexure, and Izod impact properties. The results also showed that combinations of high modulus graphite/S-glass/epoxy matrix composites exist which yield intraply hybrid laminates with the best 'balanced' properties, and that the translation efficiency of mechanical properties from the constituent composites to intraply hybrids may be assessed with a simple equation.

  6. A novel double-component MOAC honeycomb composite with pollen grains as a template for phosphoproteomics research.

    Science.gov (United States)

    Wang, Jiaxi; Li, Jie; Wang, Yanan; Gao, Mingxia; Zhang, Xiangmin; Deng, Chunhui

    2016-07-01

    The enrichment and separation of phosphopeptides from mixed biological samples is a technologically very significance, but highly challenging work. Current designed materials are mainly based on the broad and effective adsorptive character of metal oxide affinity chromatography (MOAC). Though significant progress has been made in the enrichment of phosphopeptides with MOAC material, there are chances for further development. In this study, a novel pollen-based MOAC honeycomb material was firstly explored in which the suitable hydrophilic channels preferentially enrich much more endogenous phosphopeptides than nonphosphopeptides or proteins while doping binary metal oxides at the atomic level and the ultra-high specific surface area have further allowed it to possess more effective active sites. Based on these unique features, the pollen-based material exhibited high selectivity for β-casein (mass ratio of β-casein/BSA, 1:1500), ultra-low detection limit (0.1fmol), desirable reusability. Moreover, the bionics MOAC composites were investigated in the enrichment of phosphopeptides from nonfat milk, human serum (male and female at the same age) and mice liver, results of which indicate the great potential of the composite for the phosphoproteome analysis of complex biological samples through the cheap and environmentally friendly process.

  7. 蜂窝复合地板在机场摆渡车上的应用%Application of Honeycomb Composite Panel to Airport Shuttle Bus

    Institute of Scientific and Technical Information of China (English)

    陈斌; 吴明松; 曾柳妃

    2016-01-01

    Honeycomb composite panel is a high-performance structure material with advantages such as lightweight, shock damper, heat insulation, sound insulation, etc. The authors introduce the structure characteristics of honeycomb composite panel and its practical application situation to airport shuttle bus, also analyze the results of lightweight and economy.%蜂窝复合地板是一种高效材料,具有轻质、抗振、隔热、隔音等性能优点。文章介绍蜂窝复合地板的结构特点,阐述其在机场摆渡车上的实际应用情况,并分析轻量化结果和经济性效益。

  8. Evaluation of Material Models within LS-DYNA(Registered TradeMark) for a Kevlar/Epoxy Composite Honeycomb

    Science.gov (United States)

    Polanco, Michael A.; Kellas, Sotiris; Jackson, Karen

    2009-01-01

    The performance of material models to simulate a novel composite honeycomb Deployable Energy Absorber (DEA) was evaluated using the nonlinear explicit dynamic finite element code LS-DYNA(Registered TradeMark). Prototypes of the DEA concept were manufactured using a Kevlar/Epoxy composite material in which the fibers are oriented at +/-45 degrees with respect to the loading axis. The development of the DEA has included laboratory tests at subcomponent and component levels such as three-point bend testing of single hexagonal cells, dynamic crush testing of single multi-cell components, and impact testing of a full-scale fuselage section fitted with a system of DEA components onto multi-terrain environments. Due to the thin nature of the cell walls, the DEA was modeled using shell elements. In an attempt to simulate the dynamic response of the DEA, it was first represented using *MAT_LAMINATED_COMPOSITE_FABRIC, or *MAT_58, in LS-DYNA. Values for each parameter within the material model were generated such that an in-plane isotropic configuration for the DEA material was assumed. Analytical predictions showed that the load-deflection behavior of a single-cell during three-point bending was within the range of test data, but predicted the DEA crush response to be very stiff. In addition, a *MAT_PIECEWISE_LINEAR_PLASTICITY, or *MAT_24, material model in LS-DYNA was developed, which represented the Kevlar/Epoxy composite as an isotropic elastic-plastic material with input from +/-45 degrees tensile coupon data. The predicted crush response matched that of the test and localized folding patterns of the DEA were captured under compression, but the model failed to predict the single-cell three-point bending response.

  9. Intraply Hybrid Composites Would Contain Control Strips

    Science.gov (United States)

    Chamis, Christos C.; Shiao, Chi-Yu

    1996-01-01

    "Smart" structural components with sensors and/or actuators distributed throughout their volumes made of intraply hybrid composite materials, according to proposal. Strips of hybrid control material interspersed with strips of ordinary (passive) composite material in some layers, providing distributed control capability. For example, near and far edges of plate bent upward by commanding bottom control strips to expand and simultaneously commanding upper control strips to contract.

  10. Prediction of properties of intraply hybrid composites

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1979-01-01

    Equations based on the mixtures rule are presented for predicting the physical, thermal, hygral, and mechanical properties of unidirectional intraply hybrid composites (UIHC) from the corresponding properties of their constituent composites. Bounds were derived for uniaxial longitudinal strengths, tension, compression, and flexure of UIHC. The equations predict shear and flexural properties which agree with experimental data from UIHC. Use of these equations in a composites mechanics computer code predicted flexural moduli which agree with experimental data from various intraply hybrid angleplied laminates (IHAL). It is indicated, briefly, how these equations can be used in conjunction with composite mechanics and structural analysis during the analysis/design process.

  11. Interface Characteristics of Wood-hybrid Composites

    Institute of Scientific and Technical Information of China (English)

    XUEFenglian; ZHAOGuangjie

    2005-01-01

    In order to understand the current interface characteristics of wood-hybrid composites, this paper starts off from the concept of composite interface and general theory of interface form, then the inner-surface and microstructure of wood and the interface characteristics of composites, such as wood- inorganic, wood-plastic and wood- metal made by electroless plating technique, are concluded and discussed in detail. Meanwhile,on the basis of that, some points of view about how to develop the wood-hybrid composites interface research in the future are also proposed.

  12. 蜂窝夹层复合材料不确定性参数识别方法%Parameter identification approach of honeycomb sandwich composite with uncertainties

    Institute of Scientific and Technical Information of China (English)

    姜东; 吴邵庆; 费庆国; 韩晓林

    2015-01-01

    An approach of parameter identification for predicting uncertainties in honeycomb sandwich composite is provided.The initial finite element model of a honeycomb plate is constructed by the application of an appropriate sandwich theory,in which the equivalent parameters were predicted by homogenization method.According to the analysis of the internal honeycomb structure and the relative sensitivity of eigenvalues with respect to system parameters,the sensitive parameters including the uncertainties (Gcxz,Gcyz and thickness of the face sheet)are selected to be identified. Through modal experiments of six different honeycomb plates with free-free boundary condition,the mean values and deviations of the modal frequencies are obtained,using which the uncertain parameter identification of honeycomb sandwich plate is conducted.Identification results show that when considering the uncertainty in honeycomb sandwich composite,the proposed identification method can be used for accurately identifying the mean values and deviations of the uncertain parameters and the dynamical finite element model with statistical significance can be constructed.%提出蜂窝夹层复合材料不确定性参数识别方法。采用三明治夹芯板理论建立铝蜂窝夹层结构的初始有限元模型,其中芯层等效弹性参数由均匀化方法计算。据芯层结构及相对灵敏度分析,选存在不确定性且对动态特性敏感性较大的面外剪切模量及面板厚度为待识别参数。对6块铝蜂窝复合材料板进行自由-自由边界条件下动态试验,获得试验模态参数的均值及标准差。据试验结果采用所提方法识别铝蜂窝夹层板不确定性参数。结果表明,对存在不确定性参数的铝蜂窝夹层复合材料用该方法能准确识别参数的均值及标准差,并建立具有准确统计意义的动力学模型。

  13. Biomimetic heterogeneous multiple ion channels: a honeycomb structure composite film generated by breath figures

    Science.gov (United States)

    Han, Keyu; Heng, Liping; Wen, Liping; Jiang, Lei

    2016-06-01

    We design a novel type of artificial multiple nanochannel system with remarkable ion rectification behavior via a facile breath figure (BF) method. Notably, even though the charge polarity in the channel wall reverses under different pH values, this nanofluidic device displays the same ionic rectification direction. Compared with traditional nanochannels, this composite multiple ion channel device can be more easily obtained and has directional ionic rectification advantages, which can be applied in many fields.We design a novel type of artificial multiple nanochannel system with remarkable ion rectification behavior via a facile breath figure (BF) method. Notably, even though the charge polarity in the channel wall reverses under different pH values, this nanofluidic device displays the same ionic rectification direction. Compared with traditional nanochannels, this composite multiple ion channel device can be more easily obtained and has directional ionic rectification advantages, which can be applied in many fields. Electronic supplementary information (ESI) available: Pore size distribution histograms of the AAO substrates; SEM images of the side view of pure AAO membranes and top view of the flat PI/AAO composite film; the current-time curves of the flat composite film; the current-voltage characteristics curves of pure AAO nanochannels with different mean pore diameters; CA of the two surfaces of the composite PI/AAO film, the structural formula of the polymer polyimide resin (PI), and solid surface zeta potential. See DOI: 10.1039/c6nr02506d

  14. Clinical applications of preheated hybrid resin composite.

    Science.gov (United States)

    Rickman, L J; Padipatvuthikul, P; Chee, B

    2011-07-22

    This clinical article describes and discusses the use of preheated nanohybrid resin composite for the placement of direct restorations and luting of porcelain laminate veneers. Two clinical cases are presented. Preheating hybrid composite decreases its viscosity and film thickness offering the clinician improved handling. Preheating also facilitates the use of nanohybrid composite as a veneer luting material with relatively low polymerisation shrinkage and coefficient of thermal expansion compared to currently available resin luting cements.

  15. Predicting the Dynamic Crushing Response of a Composite Honeycomb Energy Absorber Using Solid-Element-Based Models in LS-DYNA

    Science.gov (United States)

    Jackson, Karen E.

    2010-01-01

    This paper describes an analytical study that was performed as part of the development of an externally deployable energy absorber (DEA) concept. The concept consists of a composite honeycomb structure that can be stowed until needed to provide energy attenuation during a crash event, much like an external airbag system. One goal of the DEA development project was to generate a robust and reliable Finite Element Model (FEM) of the DEA that could be used to accurately predict its crush response under dynamic loading. The results of dynamic crush tests of 50-, 104-, and 68-cell DEA components are presented, and compared with simulation results from a solid-element FEM. Simulations of the FEM were performed in LS-DYNA(Registered TradeMark) to compare the capabilities of three different material models: MAT 63 (crushable foam), MAT 26 (honeycomb), and MAT 126 (modified honeycomb). These material models are evaluated to determine if they can be used to accurately predict both the uniform crushing and final compaction phases of the DEA for normal and off-axis loading conditions

  16. Hybrid Ceramic Matrix Fibrous Composites: an Overview

    Energy Technology Data Exchange (ETDEWEB)

    Naslain, R, E-mail: naslain@lcts.u-bordeaux1.fr [University of Bordeaux 3, Allee de La Boetie, 33600 Pessac (France)

    2011-10-29

    Ceramic-Matrix Composites (CMCs) consist of a ceramic fiber architecture in a ceramic matrix, bonded together through a thin interphase. The present contribution is limited to non-oxide CMCs. Their constituents being oxidation-prone, they are protected by external coatings. We state here that CMCs display a hybrid feature, when at least one of their components is not homogeneous from a chemical or microstructural standpoint. Hybrid fiber architectures are used to tailor the mechanical or thermal CMC-properties whereas hybrid interphases, matrices and coatings to improve CMC resistance to aggressive environments.

  17. Probabilistic assessment of uncertain adaptive hybrid composites

    Science.gov (United States)

    Shiao, Michael C.; Singhal, Surendra N.; Chamis, Christos C.

    1994-01-01

    Adaptive composite structures using actuation materials, such as piezoelectric fibers, were assessed probabilistically utilizing intraply hybrid composite mechanics in conjunction with probabilistic composite structural analysis. Uncertainties associated with the actuation material as well as the uncertainties in the regular (traditional) composite material properties were quantified and considered in the assessment. Static and buckling analyses were performed for rectangular panels with various boundary conditions and different control arrangements. The probability density functions of the structural behavior, such as maximum displacement and critical buckling load, were computationally simulated. The results of the assessment indicate that improved design and reliability can be achieved with actuation material.

  18. Characterization of Hybrid CNT Polymer Matrix Composites

    Science.gov (United States)

    Grimsley, Brian W.; Cano, Roberto J.; Kinney, Megan C.; Pressley, James; Sauti, Godfrey; Czabaj, Michael W.; Kim, Jae-Woo; Siochi, Emilie J.

    2015-01-01

    Carbon nanotubes (CNTs) have been studied extensively since their discovery and demonstrated at the nanoscale superior mechanical, electrical and thermal properties in comparison to micro and macro scale properties of conventional engineering materials. This combination of properties suggests their potential to enhance multi-functionality of composites in regions of primary structures on aerospace vehicles where lightweight materials with improved thermal and electrical conductivity are desirable. In this study, hybrid multifunctional polymer matrix composites were fabricated by interleaving layers of CNT sheets into Hexcel® IM7/8552 prepreg, a well-characterized toughened epoxy carbon fiber reinforced polymer (CFRP) composite. The resin content of these interleaved CNT sheets, as well as ply stacking location were varied to determine the effects on the electrical, thermal, and mechanical performance of the composites. The direct-current electrical conductivity of the hybrid CNT composites was characterized by in-line and Montgomery four-probe methods. For [0](sub 20) laminates containing a single layer of CNT sheet between each ply of IM7/8552, in-plane electrical conductivity of the hybrid laminate increased significantly, while in-plane thermal conductivity increased only slightly in comparison to the control IM7/8552 laminates. Photo-microscopy and short beam shear (SBS) strength tests were used to characterize the consolidation quality of the fabricated laminates. Hybrid panels fabricated without any pretreatment of the CNT sheets resulted in a SBS strength reduction of 70 percent. Aligning the tubes and pre-infusing the CNT sheets with resin significantly improved the SBS strength of the hybrid composite To determine the cause of this performance reduction, Mode I and Mode II fracture toughness of the CNT sheet to CFRP interface was characterized by double cantilever beam (DCB) and end notch flexure (ENF) testing, respectively. Results are compared to the

  19. Fiber release characteristics of graphite hybrid composites

    Science.gov (United States)

    Henshaw, J.

    1980-01-01

    The paper considers different material concepts that can be fabricated of hybridized composites which demonstrate improved graphite fiber retention capability in a severe fire without significant reduction to the composite properties. More than 30 panels were fabricated for mechanical and fire tests, the details and results of which are presented. Methods of composite hybridization investigated included the addition of oxidation resistant fillers to the resin, mechanically interlocking the graphite fibers by the use of woven fabrics, and the addition of glass fibers and glass additives designed to melt and fuse the graphite fibers together. It is concluded that a woven fabric with a serving of glass around each graphite tow is by far the superior of those evaluated: not only is there a coalescing effect in each graphite layer, but there is also a definite adhesion of each layer to its neighbor.

  20. Composite technologies on 3-D honeycomb structural textile%蜂窝结构三维纺织品的复合工艺开发

    Institute of Scientific and Technical Information of China (English)

    龚小舟; 华婷; 裴鹏英; 李宇

    2016-01-01

    针对具有蜂窝状结构的三维纺织品在复合工艺中存在难以成型、脱模困难的问题,拟采用对传统手糊工艺和真空辅助树脂传递模塑( VARTM)工艺进行改进的方法,对这种结构的纺织品进行复合工艺的新开发。在上述2种传统复合工艺的基础上,采用不同材质的支撑物将平面织物塑造成立体结构的蜂窝材料或对树脂注入口的位置、数量进行调整,制备出5组试样。结果表明:采用手糊工艺制成的蜂窝结构复合材料的厚度误差可达60%以上,得不到理想的试样;但采用VARTM工艺再结合石蜡作为结构内部支撑材料并采用水浴加热,可成功地制备出蜂窝结构复合材料。%During the composite molding processes for the 3⁃D honeycomb structural textiles, problems such as the difficulties in forming the composite and demolding exist after the composite is cured. It is essential to find a method to improve the traditional hand lay⁃up process and vacuum assisted resin transfer mold ( VARTM ) process to mold the 2⁃D honeycomb weave fabric into a 3⁃D structural composite. By adapting the methods such as inserting various preforms in the cells of the fabric to consolidate it into a 3⁃D honecycomb structural composite,or by adjusting the positions and number of the resin injections for the fabric to be immersed completely, five samples are produced for comparison test. The test results show that by employing the hand lay⁃up technology, 60% of error exists among the thickness of the samples. Under the condition of water bath, however, if the VARTM technology combined with wax is adopted to prepare the composite, a well presented 3⁃D honeycomb structural composite can be obtained.

  1. A Damage Tolerance Comparison of Composite Hat-Stiffened and Honeycomb Sandwich Structure for Launch Vehicle Interstage Applications

    Science.gov (United States)

    Nettles, A. T.

    2011-01-01

    In this study, a direct comparison of the compression-after-impact (CAI) strength of impact-damaged, hat-stiffened and honeycomb sandwich structure for launch vehicle use was made. The specimens used consisted of small substructure designed to carry a line load of approx..3,000 lb/in. Damage was inflicted upon the specimens via drop weight impact. Infrared thermography was used to examine the extent of planar damage in the specimens. The specimens were prepared for compression testing to obtain residual compression strength versus damage severity curves. Results show that when weight of the structure is factored in, both types of structure had about the same CAI strength for a given damage level. The main difference was that the hat-stiffened specimens exhibited a multiphase failure whereas the honeycomb sandwich structure failed catastrophically.

  2. Dynamic impact response of high-density square honeycombs made of TRIP steel and TRIP matrix composite material

    Directory of Open Access Journals (Sweden)

    Weigelt C.

    2012-08-01

    Full Text Available Two designs of square-celled metallic honeycomb structures fabricated by a modified extrusion technology based on a powder feedstock were investigated. The strength and ductility of these cellular materials are achieved by an austenitic CrNi (AISI 304 steel matrix particle reinforced by an MgO partially-stabilized zirconia building up their cell wall microstructure. Similar to the mechanical behaviour of the bulk materials, the strengthening mechanism and the martensitic phase transformations in the cell walls are affected by the deformation temperature and the nominal strain rate. The microstructure evolution during quasi-static and dynamic impact compression up to high strain rates of 103 1/s influences the buckling and failure behaviour of the honeycomb structures. In contrast to bending-dominated quasi-isotropic networks like open-celled metal foams, axial compressive loading to the honeycomb’s channels causes membrane stretching as well as crushing of the vertical cell node elements and cell walls. The presented honeycomb materials differ geometrically in their cell wall thickness-to-cell size-ratio. Therefore, the failure behaviour is predominantly controlled by global buckling and torsional-flexural buckling, respectively, accompanied by plastic matrix flow and strengthening of the cell wall microstructure.

  3. Prediction of popcorn hybrid and composite means

    Directory of Open Access Journals (Sweden)

    Ramon Macedo Rangel

    2007-01-01

    Full Text Available The objectives of this study were to evaluate the combining ability of 10 popcorn populations in a circulantdiallel; to test the viability of superior hybrids; and to identify genetic composites for intrapopulation breeding. In fourcontrasting environments, 30 treatments were evaluated for grain yield (GY, plant height (PLH and popping expansion(PE, in a random block design with four replications. Results indicated that the evaluation of treatments in a larger groupof environments favors the expression of variability in genotypes. The additive effects for PE and the dominance effects forGY and PLH were highest. GY and PE of the combinations UNB2U-C1 x Angela and Braskalb x Angela were outstanding.The predicted mean PE and GY were highest for hybrid UNB2U-C1 x Angela and the composite formed by these parents(26.54 mL g-1 and 1,446.09 kg ha-1 respectively.

  4. Manufacturing of aluminium nano hybrid composites: a state of review

    Science.gov (United States)

    Madhukar, P.; Selvaraj, N.; Rao, CSP

    2016-09-01

    This paper gives the details of hybrid composites, their fabrication methods and evaluation of mechanical, tribological behaviour and machining characteristics. Investigations on the various aspects of Hybrid composites furnish several conclusions regarding the influence of various parameters on the performance of the composites. Mostly micro structures of the hybrid composites fabricated through casting routes have been found to be stable with the distribution of uniformed reinforce particles. therefore, the hybrid composites can be constructed with various combinations of reinforcements to carry out desirable mechanical properties. The density of Hybrid composites increases with increasing reinforcements such as SiC, TiC, B4C....etc, while incorporation of partial reinforcements like fly ash, mica, rice husk, etc. reduces the density of composites. The study also reports that the hybrid composites can be treated as a replacement for regular composite materials in different advanced applications.

  5. Efficient boron abstraction using honeycomb-like porous magnetic hybrids: Assessment of techno-economic recovery of boric acid.

    Science.gov (United States)

    Oladipo, Akeem Adeyemi; Gazi, Mustafa

    2016-12-01

    Porous magnetic hybrids were synthesized and functionalized with glycidol to produce boron-selective adsorbent. The magnetic hybrid (MH) comparatively out-performed the existing expensive adsorbents. MH had a saturation magnetisation of 63.48 emu/g and average pore diameter ranging from meso to macropores. The magnetic hybrids showed excellent selectivity towards boron and resulted in 79-93% boron removal even in the presence of competing metal ions (Na(+) and Cr(2+)). Experiments were performed in a column system, and breakthrough time was observed to increase with bed depths and decreased with flow rates. The batch experiments revealed that 60 min was enough to achieve equilibrium, and the level of boron sorption was 108.5 mg/g from a synthetic solution. Several adsorption-desorption cycles were performed using a simple acid-water treatment and evaluated using various kinetic models. The spent adsorbents could be separated easily from the mixture by an external magnetic field. The cost-benefit analysis was performed for the treatment of 72 m(3)/year boron effluent, including five years straight line depreciation charges of equipment. The net profit and standard percentage confirmed that the recovery process is economically feasible.

  6. Capturing Gases in Carbon Honeycomb

    Science.gov (United States)

    Krainyukova, Nina V.

    2017-04-01

    In our recent paper (Krainyukova and Zubarev in Phys Rev Lett 116:055501, 2016. doi: 10.1103/PhysRevLett.116.055501) we reported the observation of an exceptionally stable honeycomb carbon allotrope obtained by deposition of vacuum-sublimated graphite. A family of structures can be built from absolutely dominant {sp}2-bonded carbon atoms, and may be considered as three-dimensional graphene. Such structures demonstrate high absorption capacity for gases and liquids. In this work we show that the formation of honeycomb structures is highly sensitive to the carbon evaporation temperature and deposition rates. Both parameters are controlled by the electric current flowing through thin carbon rods. Two distinctly different regimes were found. At lower electric currents almost pure honeycomb structures form owing to sublimation. At higher currents the surface-to-bulk rod melting is observed. In the latter case densification of the carbon structures and a large contribution of glassy graphite emerge. The experimental diffraction patterns from honeycomb structures filled with absorbed gases and analyzed by the advanced method are consistent with the proposed models for composites which are different for Ar, Kr and Xe atoms in carbon matrices.

  7. Capturing Gases in Carbon Honeycomb

    Science.gov (United States)

    Krainyukova, Nina V.

    2016-12-01

    In our recent paper (Krainyukova and Zubarev in Phys Rev Lett 116:055501, 2016. doi: 10.1103/PhysRevLett.116.055501) we reported the observation of an exceptionally stable honeycomb carbon allotrope obtained by deposition of vacuum-sublimated graphite. A family of structures can be built from absolutely dominant {sp}2 -bonded carbon atoms, and may be considered as three-dimensional graphene. Such structures demonstrate high absorption capacity for gases and liquids. In this work we show that the formation of honeycomb structures is highly sensitive to the carbon evaporation temperature and deposition rates. Both parameters are controlled by the electric current flowing through thin carbon rods. Two distinctly different regimes were found. At lower electric currents almost pure honeycomb structures form owing to sublimation. At higher currents the surface-to-bulk rod melting is observed. In the latter case densification of the carbon structures and a large contribution of glassy graphite emerge. The experimental diffraction patterns from honeycomb structures filled with absorbed gases and analyzed by the advanced method are consistent with the proposed models for composites which are different for Ar, Kr and Xe atoms in carbon matrices.

  8. Resin infusion of layered metal/composite hybrid and resulting metal/composite hybrid laminate

    Science.gov (United States)

    Cano, Roberto J. (Inventor); Grimsley, Brian W. (Inventor); Weiser, Erik S. (Inventor); Jensen, Brian J. (Inventor)

    2009-01-01

    A method of fabricating a metal/composite hybrid laminate is provided. One or more layered arrangements are stacked on a solid base to form a layered structure. Each layered arrangement is defined by a fibrous material and a perforated metal sheet. A resin in its liquid state is introduced along a portion of the layered structure while a differential pressure is applied across the laminate structure until the resin permeates the fibrous material of each layered arrangement and fills perforations in each perforated metal sheet. The resin is cured thereby yielding a metal/composite hybrid laminate.

  9. Use of LS-DYNA(Registered TradeMark) to Assess the Energy Absorption Performance of a Shell-Based Kevlar(TradeMark)/Epoxy Composite Honeycomb

    Science.gov (United States)

    Polanco, Michael

    2010-01-01

    The forward and vertical impact stability of a composite honeycomb Deployable Energy Absorber (DEA) was evaluated during a full-scale crash test of an MD-500 helicopter at NASA Langley?s Landing and Impact Research Facility. The lower skin of the helicopter was retrofitted with DEA components to protect the airframe subfloor upon impact and to mitigate loads transmitted to Anthropomorphic Test Device (ATD) occupants. To facilitate the design of the DEA for this test, an analytical study was conducted using LS-DYNA(Registered TradeMark) to evaluate the performance of a shell-based DEA incorporating different angular cell orientations as well as simultaneous vertical and forward impact conditions. By conducting this study, guidance was provided in obtaining an optimum design for the DEA that would dissipate the kinetic energy of the airframe while maintaining forward and vertical impact stability.

  10. Properties of hybrid resin composite systems containing prepolymerized filler particles.

    Science.gov (United States)

    Blackham, Jason T; Vandewalle, Kraig S; Lien, Wen

    2009-01-01

    This study compared the properties of newer hybrid resin composites with prepolymerized-filler particles to traditional hybrids and a microfill composite. The following properties were examined per composite: diametral tensile strength, flexural strength/modulus, Knoop microhardness and polymerization shrinkage. Physical properties were determined for each Jason T Blackham, DMD, USAF, General Dentistry, Tyndall composite group (n = 8), showing significant differences between groups per property (p hybrid composites (Z250, Esthet-X) had higher strength, composites containing pre-polymerized fillers (Gradia Direct Posterior, Premise) performed more moderately and the microfill composite (Durafill VS) had lower strength. Premise and Durafill VS had the lowest polymerization shrinkage.

  11. Sound radiation and transmission loss characteristics of a honeycomb sandwich panel with composite facings: Effect of inherent material damping

    Science.gov (United States)

    Arunkumar, M. P.; Jagadeesh, M.; Pitchaimani, Jeyaraj; Gangadharan, K. V.; Babu, M. C. Lenin

    2016-11-01

    This paper presents the results of numerical studies carried out on vibro-acoustic and sound transmission loss behaviour of aluminium honeycomb core sandwich panel with fibre reinforced plastic (FRP) facings. Layered structural shell element with equivalent orthotropic elastic properties of core and orthotropic properties of FRP facing layer is used to predict the free and forced vibration characteristics. Followed by this, acoustic response and transmission loss characteristics are obtained using Rayleigh integral. Vibration and acoustic characteristics of FRP sandwich panels are compared with aluminium sandwich panels. The result reveals that FRP panel has better vibro-acoustic and transmission loss characteristics due to high stiffness and inherent material damping associated with them. Resonant amplitudes of the response are fully controlled by modal damping factors calculated based on modal strain energy. It is also demonstrated that FRP panel can be used to replace the aluminium panel without losing acoustic comfort with nearly 40 percent weight reduction.

  12. Multiscale Modeling of Graphite/CNT/Epoxy Hybrid Composites

    Science.gov (United States)

    2016-03-09

    AFRL-AFOSR-VA-TR-2016-0154 Multiscale Modeling of Graphite/CNT/Epoxy Hybrid Composites Gregory Odegard MICHIGAN TECHNOLOGICAL UNIVERSITY Final Report...SUBTITLE Multiscale Modeling of Graphite/CNT/Epoxy Hybrid Composites 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-13-1-0030 5c. PROGRAM ELEMENT NUMBER...DISTRIBUTION A: Distribution approved for public release. Final Report Multiscale Modeling of Graphite/CNT/Epoxy Hybrid Composites Grant FA9550-13-1-0030 PI

  13. Fabrication and Characterization of SMA Hybrid Composites

    Science.gov (United States)

    Turner, Travis L.; Lach, Cynthia L.; Cano, Robert J.

    2001-01-01

    Results from an effort to fabrication shape memory alloy hybrid composite (SMAHC) test specimens and characterize the material system are presented in this study. The SMAHC specimens are conventional composite structures with an embedded SMA constituent. The fabrication and characterization work was undertaken to better understand the mechanics of the material system, address fabrication issues cited in the literature, and provide specimens for experimental validation of a recently developed thermomechanical model for SMAHC structures. Processes and hardware developed for fabrication of the SMAHC specimens are described. Fabrication of a SMA14C laminate with quasi-isotropic lamination and ribbon-type Nitinol actuators embedded in the 0' layers is presented. Beam specimens are machined from the laminate and are the focus of recent work, but the processes and hardware are readily extensible to more practical structures. Results of thermomechanical property testing on the composite matrix and Nitinol ribbon are presented. Test results from the Nitinol include stress-strain behavior, modulus versus temperature. and constrained recovery stress versus temperature and thermal cycle. Complex thermomechanical behaviors of the Nitinol and composite matrix are demonstrated, which have significant implications for modeling of SMAHC structures.

  14. Advanced fiber-composite hybrids--A new structural material

    Science.gov (United States)

    Chamis, C. C.; Lark, R. F.; Sullivan, T. L.

    1974-01-01

    Introduction of metal foil as part of matrix and fiber composite, or ""sandwich'', improves strength and stiffness for multidirectional loading, improves resistance to cyclic loading, and improves impact and erosion resistance of resultant fiber-composite hybrid structure.

  15. Boron/aluminum graphite/resin advanced fiber composite hybrids

    Science.gov (United States)

    Chamis, C. C.; Lark, R. F.; Sullivan, T. L.

    1975-01-01

    Fabrication feasibility and potential of an adhesively bonded metal and resin matrix fiber-composite hybrid are determined as an advanced material for aerospace and other structural applications. The results show that using this hybrid concept makes possible a composite design which, when compared with nonhybrid composites, has greater transverse strength, transverse stiffness, and impact resistance with only a small penalty on density and longitudinal properties. The results also show that laminate theory is suitable for predicting the structural response of such hybrids. The sequence of fracture modes indicates that these types of hybrids can be readily designed to meet fail-safe requirements.

  16. Hybrid composites of xanthan and magnetic nanoparticles for cellular uptake.

    Science.gov (United States)

    Bueno, Vânia Blasques; Silva, Anielle Martins; Barbosa, Leandro Ramos Souza; Catalani, Luiz Henrique; Teixeira-Neto, Erico; Cornejo, Daniel Reinaldo; Petri, Denise Freitas Siqueira

    2013-11-04

    We describe a fast and simple method to prepare composite films of magnetite nanoparticles and xanthan networks. The particles are distributed close to hybrid film surface, generating a coercivity of 27 ± 2 Oe at 300 K. The proliferation of fibroblast cells on the hybrid composites was successful, particularly when an external magnetic field was applied.

  17. Temperature Effects on Hybrid Composite Plates Under Impact Loads

    Directory of Open Access Journals (Sweden)

    Metin SAYER

    2009-03-01

    Full Text Available In this work, impact responses of carbon-glass fiber/epoxy (hybrid composites were investigated under various temperatures and increasing impact energies. The increasing impact energies were applied to the specimens at various temperatures as -20, 0, 20 and 40 oC until perforation took place of specimens. Those specimens are composed by two types of fiber orientation with eight laminates hybrid composites. An Energy profiling diagram, used for showing the relationship between impact and absorbed energy, has been used to obtain penetration and perforation thresholds of hybrid composites. Beside those, temperature effects on impact characteristics such as maximum contact force (Fmax, total deflection (d and maximum contact duration (t were also presented in figures. Finally, glass and carbon fibers exhibited more brittle characteristics at -20 oC according to other temperatures. So, perforation threshold of each hybrid composites at -20 oC was found higher than other temperatures. Keywords : Hybrid composite

  18. Fabrication of composite thin films with microstructures of honeycomb, foam, and nanosphere arrays through adsorption and self-assembly of block copolymers at the liquid/liquid interface.

    Science.gov (United States)

    Liu, Yanan; Chen, Lifang; Geng, Yuanyuan; Lee, Yong-Ill; Li, Ying; Hao, Jingcheng; Liu, Hong-Guo

    2013-10-01

    The adsorption and self-organization behaviors of two kinds of block copolymers, polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) and poly(4-vinylpyridine)-block-polystyrene-block-poly(4-vinylpyridine) (P4VP-b-PS-b-P4VP), at planar liquid/liquid interfaces were investigated. A gel film decorating with honeycomb-like microstructures forms at the liquid/liquid interface between PS-b-P4VP chloroform solution and chloroauric acid aqueous solution. However, foam films were developed when the chloroauric acid aqueous solution was replaced by a chloroplatinic acid solution or a silver nitrate solution. Furthermore, a free-standing film containing the ordered arrays of nanospheres appeared at the liquid/liquid interface between P4VP-b-PS-b-P4VP chloroform solution and chloroauric acid aqueous solution. The formation of these microstructures was attributed to the adsorption of polymer molecules, combining with inorganic ions and the self-assembly of the composite species at the interface. The doped metal ions and complex ions were transformed to metal nanoparticles after further treatment. This is a facile and convenient method to prepare polymer/inorganic nanoparticle composites. These results also indicate the great influences of the polymer structures and the inorganic species in the aqueous phases on the self-assembly behaviors of the polymers at the interfaces, the final morphology, and structure of the composites. In addition, the formed thin composite films doped with well-dispersed, homogeneous small noble metal nanoparticles exhibit great and durable catalytic activities for the reduction of 4-nitrophenol (4-NP) by potassium borohydride.

  19. Hybrid fiber and nanopowder reinforced composites for wind turbine blades

    Directory of Open Access Journals (Sweden)

    Nikoloz M. Chikhradze

    2015-01-01

    Full Text Available The results of an investigation into the production of wind turbine blades manufactured using polymer composites reinforced by hybrid (carbon, basalt, glass fibers and strengthened by various nanopowders (oxides, carbides, borides are presented. The hybrid fiber-reinforced composites (HFRC were manufactured with prepreg technology by molding pre-saturated epoxy-strengthened matrix-reinforced fabric. Performance of the manufactured composites was estimated with values of the coefficient of operating condition (COC at a moderate and elevated temperature.

  20. Control and design of volumetric composition in pultruded hybrid fibre composites

    DEFF Research Database (Denmark)

    Madsen, Bo; Hashemi, Fariborz; Tahir, Paridah

    2016-01-01

    Hybrid composites consist of two of more fibre phases in a common matrix phase. This is a challenge for the control and design of the volumetric composition and microstructural uniformity of such composites. In the present study, a model is presented for the prediction of the complete volumetric...... composition (i.e. volume fractions of fibres, matrix and porosity) in hybrid fibre composites. The model is based on a constant local fibre volume fraction criterion. Good agreement is found between model predictions and experimental data of pultruded hybrid kenaf/glass fibre composites with variable hybrid...... fibre weight mixing ratios. To demonstrate the suitability of the model, simulations are performed for four different cases of volumetric composition in hybrid kenaf/glass composites....

  1. Hybrid nanocellulose/nanoclay composites for food packaging applications

    DEFF Research Database (Denmark)

    Trifol Guzman, Jon

    to larger spherulite sizes, which had a more significant impacton water diffusion and transparency reduction but also showed an increased water sorption. Finally, it was found that cellulose nanofibers reduced water diffusion to an extent similar to C30B (21% vs.27%), while hybrid composites showed 49......% decrease, albeit CNF based composites showed increased water sorption (7% for PLA/CNF 1% composite and 9% for PLA/CNF 1%/C30B 1% when compared with neat PLA).The reduced diffusivity of the hybrid nanocomposites suggested that the material was promising for active packaging, since low diffusivity leads....../gCNF and hybrid PLA/CNF/C30B composites were prepared and evaluated on controlled release applications. It was established that the surface modification of CNF greatly enhanced the dispersion of the gCNF and that carvacrolloaded hybrid composites showed a decreased release rate, high ductility and a reduced WVTR...

  2. Evaluation of tensile strength of hybrid fiber (jute/gongura) reinforced hybrid polymer matrix composites

    Science.gov (United States)

    Venkatachalam, G.; Gautham Shankar, A.; Vijay, Kumar V.; Chandan, Byral R.; Prabaharan, G. P.; Raghav, Dasarath

    2015-07-01

    The polymer matrix composites attract many industrial applications due to its light weight, less cost and easy for manufacturing. In this paper, an attempt is made to prepare and study of the tensile strength of hybrid (two natural) fibers reinforced hybrid (Natural + Synthetic) polymer matrix composites. The samples were prepared with hybrid reinforcement consists of two different fibers such as jute and Gongura and hybrid polymer consists of polyester and cashew nut shell resins. The hybrid composites tensile strength is evaluated to study the influence of various fiber parameters on mechanical strength. The parameters considered here are the duration of fiber treatment, the concentration of alkali in fiber treatment and nature of fiber content in the composites.

  3. Super-hybrid composites - An emerging structural material

    Science.gov (United States)

    Chamis, C. C.; Lark, R. F.; Sullivan, T. L.

    1975-01-01

    Specimens of super-hybrids and advanced fiber composites were subjected to extensive tests to determine their mechanical properties, including impact and thermal fatigue. The super-hybrids were fabricated by a procedure similar to that reported by Chamis et al., (1975). Super-hybrids subjected to 1000 cycles of thermal fatigue from -100 to 300 F retained over 90% of their longitudinal flexural strength and over 75% of their transverse flexural strength; their transverse flexural strength may be as high as 8 times that of a commercially supplied boron/1100-Al composite. The thin specimen Izod longitudinal impact resistance of the super-hybrids was twice that of the boron/110-Al material. Super-hybrids subjected to transverse tensile loads exhibited nonlinear stress-strain relationships. The experimentally determined initial membrane (in-plane) and bending elastic properties of super-hybrids were predicted adequately by linear laminate analysis.

  4. Design and Ballistic Performance of Hybrid Composite Laminates

    Science.gov (United States)

    Ćwik, Tomasz K.; Iannucci, Lorenzo; Curtis, Paul; Pope, Dan

    2016-10-01

    This paper presents an initial design assessment of a series of novel, cost-effective, and hybrid composite materials for applications involving high velocity impacts. The proposed hybrid panels were designed in order to investigate various physical phenomenon occurring during high velocity impact on compliant laminates from a previous study on Dyneema® and Spectra®. In the first, screening phase of the study twenty different hybrid composite laminates were impacted with 20 mm Fragment Simulating Projectiles at 1 km/s striking velocity. The best performing concepts were put forward to phase II with other hybrid concepts involving shear thickening fluids, commonly used in low velocity impacts. The results indicated that it is possible to design hybrid laminates of similar ballistic performance as the reference Dyneema® laminate, but with lower material costs. The optimal hybrid concept involves a fibre reinforced Polypropylene front and a Dyneema® backing.

  5. Carboxylated nitrile butadiene rubber/hybrid filler composites

    Directory of Open Access Journals (Sweden)

    Ahmad Mousa

    2012-08-01

    Full Text Available The surface properties of the OSW and NLS are measured with the dynamic contact-angle technique. The x-ray photoelectron spectroscopy (XPS of the OSW reveals that the OSW possesses various reactive functional groups namely hydroxyl groups (OH. Hybrid filler from NLS and OSW were incorporated into carboxylated nitrile rubber (XNBR to produce XNBR hybrid composites. The reaction of OH groups from the OSW with COOH of the XNBR is checked by attenuated total reflectance spectra (ATR-IR of the composites. The degree of curing ΔM (maximum torque-minimum torque as a function of hybrid filler as derived from moving die rheometer (MDR is reported. The stress-strain behavior of the hybrid composites as well as the dynamic mechanical thermal analysis (DMTA is studied. Bonding quality and dispersion of the hybrid filler with and in XNBR are examined using scanning-transmission electron microscopy (STEM in SEM.

  6. Hybrid yarn for thermoplastic fibre composites. Summary of technical results

    Energy Technology Data Exchange (ETDEWEB)

    Lystrup, Aa.

    1998-01-01

    This report is a summary of the technical results obtained within the framework program: `Hybrid Yarn for Thermoplastic Fibre Composites`. The program which started at the 15th of June 1994 and expired at the 31st of December 1997, was a framework program under the Danish Materials Technology Program, MUP2. A new type of hybrid yarn for production of fibre composites with thermoplastic matrix material is developed and tested. A hybrid yarn is a commingled textured yarn consisting of structural fibres and thermoplastic fibres. In a subsequent heating and consolidation process the plastic fibres melt and become the matrix material in the formed fibre composite material. Two types of processing technology are developed and studied: Vacuum consolidation and press consolidation. Vacuum consolidation of hybrid yarn fabrics is suitable for fabrication of larger parts such as wind turbine blades, and press consolidation is a fast process suitable for smaller parts such as automobile body parts. To demonstrate the potential for industrial use of the developed hybrid yarn and process technologies a section of a wind turbine blade, an inspection cover and a car door-post have been produced. An environmental evaluation of the manufacture of hybrid yarn and composites shows that the use of the hybrid yarn is a gain for both the working environment and the external environment, compared to the use of thermosetting polymer composites. (au)

  7. Impact resistance of hybrid composite fan blade materials

    Science.gov (United States)

    Friedrich, L. A.

    1974-01-01

    Improved resistance to foreign object damage was demonstrated for hybrid composite simulated blade specimens. Transply metallic reinforcement offered additional improvement in resistance to gelatin projectile impacts. Metallic leading edge protection permitted equivalent-to-titanium performance of the hybrid composite simulated blade specimen for impacts with 1.27 cm and 2.54 cm (0.50 and 1.00 inch) diameter gelatin spheres.

  8. Freeform Honeycomb Structures

    KAUST Repository

    Jiang, Caigui

    2014-07-01

    Motivated by requirements of freeform architecture, and inspired by the geometry of hexagonal combs in beehives, this paper addresses torsion-free structures aligned with hexagonal meshes. Since repetitive geometry is a very important contribution to the reduction of production costs, we study in detail “honeycomb structures”, which are defined as torsion-free structures where the walls of cells meet at 120 degrees. Interestingly, the Gauss-Bonnet theorem is useful in deriving information on the global distribution of node axes in such honeycombs. This paper discusses the computation and modeling of honeycomb structures as well as applications, e.g. for shading systems, or for quad meshing. We consider this paper as a contribution to the wider topic of freeform patterns, polyhedral or otherwise. Such patterns require new approaches on the technical level, e.g. in the treatment of smoothness, but they also extend our view of what constitutes aesthetic freeform geometry.

  9. Nano and hybrid aluminum based metal matrix composites: an overview

    Directory of Open Access Journals (Sweden)

    Muley Aniruddha V.

    2015-01-01

    Full Text Available Aluminium matrix composites (AMCs are potential light weight engineering materials with excellent properties. AMCs find application in many areas including automobile, mining, aerospace and defence, etc. Due to technological advancements, it is possible to use nano sized reinforcement in Al matrix. Nano sized reinforcements enhance the properties of Al matrix compared to micro sized reinforcements. Hybrid reinforcement imbibe superior properties to aluminium matrix composites as compared with Al composites having single reinforcement. This paper is focused on overview of development in the field of Al based metal matrix with nano and hybrid aluminium based composites.

  10. Dry sliding wear studies of aluminum matrix hybrid composites

    Directory of Open Access Journals (Sweden)

    V.V. Monikandan

    2016-12-01

    Full Text Available In the present work, hybrid composites are fabricated with self-lubricating characteristics to make them as resource-efficient materials. AA6061-10 wt. % B4C–MoS2 hybrid composites reinforced with 2.5, 5 and 7.5 wt. % concentration of MoS2 particles are produced using stir casting technique, and mechanical and tribological properties are evaluated. Microstructural characterization of the hybrid composites revealed the uniform distribution of reinforcement (B4C and MoS2 particles in the matrix material. Hardness and fracture toughness of the hybrid composites are decreased monotonously with an increase in the addition of MoS2 particles. Dry sliding tribological studies conducted using a pin-on-disk tribotester under atmospheric conditions revealed the formation of MoS2-lubricated tribolayer on the worn pin surface which significantly influenced the tribological properties. The addition of MoS2 particles decreased the friction coefficient and wear rate of the hybrid composites. Delamination and abrasion are observed to be the controlling wear mechanisms and material in the form of platelet-shaped debris, and flow-type chip debris is formed, and a long and shallow crater on the worn pin surface of the hybrid composite is also observed.

  11. Hybrid Composite of Polyaniline Containing Carbon Nanotube

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Carbon nanotube-polyaniline hybrid material was synthesized by emulsion polymerization in-situ. The morphology of hybrid material was studied by TEM and X-ray diffraction. The conductivity of nanocomposite increases with the increasing of carbon nanotube content because of the new conductivity passageways formed by carbon nanotubes.

  12. Buckling analysis of a ring stiffened hybrid composite cylinder

    Science.gov (United States)

    Potluri, Rakesh; Eswara Kumar, A.; Navuri, Karteek; Nagaraju, M.; Mojeswara Rao, Duduku

    2016-09-01

    This study aims to understand the response of the ring stiffened cylinders made up of hybrid composites subjected to buckling loads by using the concepts of Design of Experiments (DOE) and optimization by using Finite Element Method (FEM) simulation software Ansys workbench V15. Carbon epoxy and E-glass epoxy composites were used in the hybrid composite. This hybrid composite was analyzed by using different layup angles. Central composite design (CCD) was used to perform design of experiments (D.O.E) and kriging method was used to generate a response surface. The response surface optimization (RSO) was performed by using the method of the multi-objective genetic algorithm (MOGA). After optimization, the best candidate was chosen and applied to the ring stiffened cylinder and eigenvalue buckling analysis was performed to understand the buckling behavior. Best laminate candidates with high buckling strength have been identified. A generalized procedure of the laminate optimization and analysis have been shown.

  13. Stabilization of composition fluctuations in mixed membranes by hybrid lipids

    Science.gov (United States)

    Safran, Samuel; Palmieri, Benoit

    2013-03-01

    A ternary mixture model is proposed to describe composition fluctuations in mixed membranes composed of saturated, unsaturated and hybrid lipids. The asymmetric hybrid lipid has one saturated and one unsaturated hydrocarbon chain and it can reduce the packing incompatibility between saturated and unsaturated lipids. A methodology to recast the free-energy of the lattice in terms of a continuous isotropic field theory is proposed and used to analyze composition fluctuations above the critical temperature. The effect of hybrid lipids on fluctuations domains rich in saturated/unsaturated lipids is predicted. The correlation length of such fluctuations decreases significantly with increasing amounts of hybrids even if the temperature is maintained close to the critical temperature. This provides an upper bound for the domain sizes expected in rafts stabilized by hybrids, above the critical temperature. When the hybrid composition of the membrane is increased further, a crossover value is found above which ``stripe-like'' fluctuations are observed. The wavelength of these fluctuations decreases with increasing hybrid fraction and tends toward a molecular size in a membrane that contains only hybrids.

  14. Boron/aluminum-graphite/resin advanced fiber composite hybrids

    Science.gov (United States)

    Chamis, C. C.; Lark, R. F.; Sullivan, T. L.

    1974-01-01

    An investigation was conducted to determine the fabrication feasibility and to assess the potential of adhesively-bonded metal and resin matrix fiber composite hybrids as an advanced material, for aerospace and other structural applications. The results of fabrication studies and of evaluation of physical and mechanical properties show that using this hybrid concept it is possible to design a composite which, when compared to nonhybrid composites, has improved transverse strength, transverse stiffness, and impact resistance with only a small penalty on density and longitudinal properties. The results also show that laminate theory is suitable for perdicting the structural response of such hybrids. The sequence of fracture modes indicates that these types of hybrids can be readily designed to meet fail-safe requirements.

  15. Analysis of composition and microstructural uniformity of hybrid glass/carbon fibre composites

    DEFF Research Database (Denmark)

    Beauson, Justine; Markussen, Christen Malte; Madsen, Bo

    2013-01-01

    In hybrid fibre composites, the intermixing of the two types of fibres imposes challenges to obtain materials with a well-defined and uniform microstructure. In the present paper, the composition and the microstructural uniformity of hybrid glass/carbon fibre composites mixed at the fibre bundle...... fibre volume fractions are determined using volumetric calculations. A model is presented to predict the interrelation of volume fractions in hybrid fibre composites. The microstructural uniformity of the composites is analysed by the determined variation in composite volume fractions. Two analytical...... level are investigated. The different levels of compositions in the composites are defined and experimentally determined. The composite volume fractions are determined using an image analysis based procedure. The global fibre volume fractions are determined using a gravimetrical based method. The local...

  16. Multifunctional Hybrid Carbon Nanotube/Carbon Fiber Polymer Composites

    Science.gov (United States)

    Kang, Jin Ho; Cano, Roberto J.; Ratcliffe, James G.; Luong, Hoa; Grimsley, Brian W.; Siochi, Emilie J.

    2016-01-01

    For aircraft primary structures, carbon fiber reinforced polymer (CFRP) composites possess many advantages over conventional aluminum alloys due to their light weight, higher strengthand stiffness-to-weight ratio, and low life-cycle maintenance costs. However, the relatively low electrical and thermal conductivities of CFRP composites fail to provide structural safety in certain operational conditions such as lightning strikes. Despite several attempts to solve these issues with the addition of carbon nanotubes (CNT) into polymer matrices, and/or by interleaving CNT sheets between conventional carbon fiber (CF) composite layers, there are still interfacial problems that exist between CNTs (or CF) and the resin. In this study, hybrid CNT/CF polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel® IM7/8852 prepreg. Resin concentrations from 1 wt% to 50 wt% were used to infuse the CNT sheets prior to composite fabrication. The interlaminar properties of the resulting hybrid composites were characterized by mode I and II fracture toughness testing (double cantilever beam and end-notched flexure test). Fractographical analysis was performed to study the effect of resin concentration. In addition, multi-directional physical properties like thermal conductivity of the orthotropic hybrid polymer composite were evaluated. Interleaving CNT sheets significantly improved the in-plane (axial and perpendicular direction of CF alignment) thermal conductivity of the hybrid composite laminates by 50 - 400%.

  17. Sound insulation of honeycomb weave fabric reinforced polyvinyl chloride composite%蜂窝织物增强聚氯乙烯复合材料的隔音性能

    Institute of Scientific and Technical Information of China (English)

    杨天兵; 傅雅琴

    2011-01-01

    In order to study the acoustic insulation property of honeycomb weave fabric/PVC composite material, a honeycomb weave fabric with the same surface density but different repetitions of weave was woven on an automatic sample loom using 58.3 tex × 2 cotton yarn as warp and weft. Honeycomb weave fabric/PVC composite material was fabricated using the halloysite nanotubes (HNTs) filled polyvinyl chloride (PVC) as substrate, and then a sandwich structure composite was made with the honeycomb weave fabric/PVC composite as core material. The sound insulation quality of prepared samples was tested by acoustic analyzer of two-channel. The results showed that repetitions of weave have great influence on the sound insulation effect of honeycomb weave fabric. When the repetitions of weave are 6, the composite material displays good sound insulation. In the case of sandwich composite material with the honeycomb weave fabric/PVC composite as core material, it exhibits good sound insulation to low frequency when the repetitions of weave are 6, and its good sound insulation to high frequency is found when the repetitions of weave are 14.%为研究蜂窝织物聚氯乙烯(PVC)复合材料的隔音性能,选用58.3 tex×2的棉纱为经纬纱,在自动织样机上织造面密度基本相同而组织循环数不同的蜂窝织物,以埃洛石纳米管(HNTs)填充的PVC为基体,制备蜂窝织物/PVC复合材料,再以蜂窝织物/PVC复合材料为芯材,制备三明治结构复合材料.采用双声道声学分析仪,对制备样品的隔音性能进行测试和分析.结果表明:不同循环数的蜂窝织物对复合材料的隔音效果有很大影响,当组织循环数为6时,复合材料显示了良好的隔音效果;对于蜂窝织物复合材料作为芯材的三明治结构复合材料而言,组织循环数为6时,对低频具有良好的隔音性能,组织循环数为14时,对高频率具有良好的隔音性能.

  18. Analysis/design of strip reinforced random composites (strip hybrids)

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1978-01-01

    Advanced analysis methods and composite mechanics were applied to a strip-reinforced random composite square panel with fixed ends to illustrate the use of these methods for the a priori assessment of the composite panel when subjected to complex loading conditions. The panel was assumed to be of E-glass random composite. The strips were assumed to be of three advanced unidirectional composites to cover a range of low, intermediate, and high modulus stiffness. The panels were assumed to be subjected to complex loadings to assess their adequacy as load-carrying members in auto body, aircraft engine nacelle and windmill blade applications. The results show that strip hybrid panels can be several times more structurally efficient than the random composite base materials. Some of the results are presented in graphical form and procedures are described for use of these graphs as guides for preliminary design of strip hybrids.

  19. Analysis/design of strip reinforced random composites /strip hybrids/

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1978-01-01

    Results are described which were obtained by applying advanced analysis methods and composite mechanics to a strip-reinforced random composite square panel with fixed ends. This was done in order to illustrate the use of these methods for the apriori assessment of the composite panel when subjected to complex loading conditions. The panel was assumed to be of E-Glass/Random Composite. The strips were assumed to be of three advanced unidirectional composites to cover a range of low, intermediate, and high modulus stiffness. The panels were assumed to be subjected to complex loadings to assess their adequacy as load-carrying members in auto body, aircraft engine nacelle, and windmill blade applications. The results show that strip hybrid panels can be several times more structurally efficient than the random composite base materials. Some of the results are presented in graphical form and procedures are described for use of these graphs as guides for preliminary design of strip hybrids.

  20. Computational simulation of intermingled-fiber hybrid composite behavior

    Science.gov (United States)

    Mital, Subodh K.; Chamis, Christos C.

    1992-01-01

    Three-dimensional finite-element analysis and a micromechanics based computer code ICAN (Integrated Composite Analyzer) are used to predict the composite properties and microstresses of a unidirectional graphite/epoxy primary composite with varying percentages of S-glass fibers used as hydridizing fibers at a total fiber volume of 0.54. The three-dimensional finite-element model used in the analyses consists of a group of nine fibers, all unidirectional, in a three-by-three unit cell array. There is generally good agreement between the composite properties and microstresses obtained from both methods. The results indicate that the finite-element methods and the micromechanics equations embedded in the ICAN computer code can be used to obtain the properties of intermingled fiber hybrid composites needed for the analysis/design of hybrid composite structures. However, the finite-element model should be big enough to be able to simulate the conditions assumed in the micromechanics equations.

  1. Probing Compositional Variation within Hybrid Nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Yuhas, Benjamin D.; Habas, Susan E.; Fakra, Sirine C.; Mokari, Taleb

    2010-06-22

    We present a detailed analysis of the structural and magnetic properties of solution-grown PtCo-CdS hybrid structures in comparison to similar free-standing PtCo alloy nanoparticles. X-ray absorption spectroscopy is utilized as a sensitive probe for identifying subtle differences in the structure of the hybrid materials. We found that the growth of bimetallic tips on a CdS nanorod substrate leads to a more complex nanoparticle structure composed of a PtCo alloy core and thin CoO shell. The core-shell architecture is an unexpected consequence of the different nanoparticle growth mechanism on the nanorod tip, as compared to free growth in solution. Magnetic measurements indicate that the PtCo-CdS hybrid structures are superparamagnetic despite the presence of a CoO shell. The use of X-ray spectroscopic techniques to detect minute differences in atomic structure and bonding in complex nanosystems makes it possible to better understand and predict catalytic or magnetic properties for nanoscale bimetallic hybrid materials.

  2. Hybridization Induced Transparency in composites of metamaterials and atomic media

    CERN Document Server

    Weis, Peter; Beigang, René; Rahm, Marco

    2011-01-01

    We report hybridization induced transparency (HIT) in a composite medium consisting of a metamaterial and a dielectric. We develop an analytic model that explains HIT by coherent coupling between the hybridized local fields of the metamaterial and the dielectric or an atomic system in general. In a proof-of-principle experiment, we evidence HIT in a split ring resonator metamaterial that is coupled to \\alpha-lactose monohydrate. Both, the analytic model and numerical calculations confirm and explain the experimental observations. HIT can be considered as a hybrid analogue to electromagnetically induced transparency (EIT) and plasmon-induced transparency (PIT).

  3. Topologically ordered magnesium-biopolymer hybrid composite structures.

    Science.gov (United States)

    Oosterbeek, Reece N; Seal, Christopher K; Staiger, Mark P; Hyland, Margaret M

    2015-01-01

    Magnesium and its alloys are intriguing as possible biodegradable biomaterials due to their unique combination of biodegradability and high specific mechanical properties. However, uncontrolled biodegradation of magnesium during implantation remains a major challenge in spite of the use of alloying and protective coatings. In this study, a hybrid composite structure of magnesium metal and a biopolymer was fabricated as an alternative approach to control the corrosion rate of magnesium. A multistep process that combines metal foam production and injection molding was developed to create a hybrid composite structure that is topologically ordered in all three dimensions. Preliminary investigations of the mechanical properties and corrosion behavior exhibited by the hybrid Mg-polymer composite structures suggest a new potential approach to the development of Mg-based biomedical devices.

  4. Properties of Co-Curing Composite Panel/Aluminium Honeycomb Sandwich Structure%共固化复合材料/铝蜂窝夹层结构性能

    Institute of Scientific and Technical Information of China (English)

    潘玲英; 孙宏杰; 尹亮; 林娜; 杨智勇

    2012-01-01

    采用共固化工艺制备了碳纤维增强复合材料面板/铝蜂窝夹层结构.通过考察固化压力对复合材料面板性能的影响确定了共固化的成型压力,对比分析了不同规格铝蜂窝及其夹层结构的力学性能.结果表明,对于薄面板,成型压力对面板力学性能的影响较小,规格为0.04 mm×4 mm 的铝蜂窝制备的夹层结构具有更高的比强度和比刚度,且成型工艺性好.%Composite panel/aluminium sandwich structure was fabricated by the co-curing process. The effect of processing pressure on the properties of composite panel was investigated to determine the co-curing pressure. The properties of aluminium honeycomb with different dimension parameter and their sandwich structures were also tested and analyzed. The results show that the processing pressure has little effect on the properties of thin composite panel. The sandwich structure fabricated by the aluminium honeycomb of 0. 04 mm×4 mm has high specific strength and modulus, and is easier to fabricate. Therefore, it has more widely potential applications.

  5. Dry sliding wear of heat treated hybrid metal matrix composites

    Science.gov (United States)

    Naveed, Mohammed; Khan, A. R. Anwar

    2016-09-01

    In recent years, there has been an ever-increasing demand for enhancing mechanical properties of Aluminum Matrix Composites (AMCs), which are finding wide applications in the field of aerospace, automobile, defence etc,. Among all available aluminium alloys, Al6061 is extensively used owing to its excellent wear resistance and ease of processing. Newer techniques of improving the hardness and wear resistance of Al6061 by dispersing an appropriate mixture of hard ceramic powder and whiskers in the aluminium alloy are gaining popularity. The conventional aluminium based composites possess only one type of reinforcements. Addition of hard reinforcements such as silicon carbide, alumina, titanium carbide, improves hardness, strength and wear resistance of the composites. However, these composites possessing hard reinforcement do posses several problems during their machining operation. AMCs reinforced with particles of Gr have been reported to be possessing better wear characteristics owing to the reduced wear because of formation of a thin layer of Gr particles, which prevents metal to metal contact of the sliding surfaces. Further, heat treatment has a profound influence on mechanical properties of heat treatable aluminium alloys and its composites. For a solutionising temperature of 5500C, solutionising duration of 1hr, ageing temperature of 1750C, quenching media and ageing duration significantly alters mechanical properties of both aluminium alloy and its composites. In the light of the above, the present paper aims at developing aluminium based hybrid metal matrix composites containing both silicon carbide and graphite and characterize their mechanical properties by subjecting it to heat treatment. Results indicate that increase of graphite content increases wear resistance of hybrid composites reinforced with constant SiC reinforcement. Further heat treatment has a profound influence on the wear resistance of the matrix alloy as well as its hybrid composites

  6. Titanium honeycomb panel testing

    Science.gov (United States)

    Richards, W. L.; Thompson, Randolph C.

    The paper describes the procedures of thermal mechanical tests carried out at the NASA Dryden Flight Research Facility on two tianium honeycomb wing panels bonded using liquid interface diffusion (LID) technique, and presents the results of these tests. The 58.4 cm square panels consisted of two 0.152-cm-thick Ti 6-2-4-2 face sheets LID-bonded to a 1.9-cm-thick honeycomb core, with bearing plates fastened to the perimeter of the upper and the lower panel surfaces. The panels were instrumented with sensors for measuring surface temperature, strain, and deflections to 315 C and 482 C. Thermal stress levels representative of those encountered during aerodynamic heating were produced by heating the upper panel surface and restraining all four edges. After more than 100 thermal cycles from room temperature to 315 C and 50 cycles from room temperature to 482 C, no significant structural degradation was detected in the panels.

  7. Hybrid Composite Structures: Multifunctionality through Metal Fibres

    NARCIS (Netherlands)

    Ahmed, T.

    2009-01-01

    The introduction of fibre reinforced polymer composites into the wings and fuselages of the newest aircraft are changing the design and manufacturing approach. Composites provide greater freedom to designers who want to improve aircraft performance in an affordable way. In this quest, researchers ar

  8. Hybrid fiber reinforcement and crack formation in Cementitious Composite Materials

    DEFF Research Database (Denmark)

    Pereira, E.B.; Fischer, Gregor; Barros, J.A.O.

    2011-01-01

    reinforcement systems. The research described in this paper shows that the multi-scale conception of cracking and the use of hybrid fiber reinforcements do not necessarily result in an improved tensile behavior of the composite. Particular material design requirements may nevertheless justify the use of hybrid......- to the macroscale. In this study, the performance of different fiber reinforced cementitious composites is assessed in terms of their tensile stress-crack opening behavior. The results obtained from this investigation allow a direct quantitative comparison of the behavior obtained from the different fiber...

  9. Hybrid filler composition optimization for tensile strength of jute fibre-reinforced polymer composite

    Indian Academy of Sciences (India)

    ANURAG GUPTA; HARI SINGH; R SWALIA

    2016-09-01

    In present research work, pultrusion process is used to develop jute fibre-reinforced polyester (GFRP) composite and experiments have been performed on an indigenously developed pultrusion experimental setup. The developed composite consists of natural jute fibre as reinforcement and unsaturated polyester resin as matrix with hybrid filler containing bagasse fibre, carbon black and calcium carbonate (CaCO$_3$). The effect of weight content of bagasse fibre, carbon black and calcium carbonate on tensile strength of pultruded GFRP composite is evaluated and the optimum hybrid filler composition for maximizing the tensile strength is determined. Different compositions of hybrid filler are prepared by mixing three fillers using Taguchi L$_9$ orthogonal array. Fifteen percent of hybrid filler of different composition by weight was mixed in the unsaturated polyester resin matrix. Taguchi L$_9$ orthogonal array (OA) has been used to plan the experiments and ANOVA is used for analysing tensile strength. A regression model has also been proposed to evaluate the tensile strength of the composite within 7% error by varying the abovefillers weight. A confirmation experiment was performed which gives 73.14 MPa tensile strength of pultruded jute fibre polymer composite at the optimum composition of hybrid filler.

  10. Investigations on mechanical properties of aluminum hybrid composites

    Directory of Open Access Journals (Sweden)

    Dora Siva Prasad

    2014-01-01

    Full Text Available A double stir casting process was used to fabricate aluminum composites reinforced with various volume fractions of 2, 4, 6, and 8 wt% RHA and SiC particulates in equal proportions. Properties such as hardness, density, porosity and mechanical behavior of the unreinforced and Al/x%RHA/x%SiC (x = 2, 4, 6, and 8 wt% reinforced hybrid composites were examined. Scanning electron microscope (model JSM-6610LV was used to study the microstructural characterization of the composites. It was observed that the hardness and porosity of the hybrid composite increased with increasing reinforcement volume fraction and density decreased with increasing particle content. It was also observed that the UTS and yield strength increase with an increase in the percent weight fraction of the reinforcement particles, whereas elongation decreases with the increase in reinforcement. The increase in strength of the hybrid composites is probably due to the increase in dislocation density. A systematic study of the base alloy and composites was done using the Brinell hardness measurement and the corresponding age hardening curves were obtained. It was observed that in comparison to that of the base aluminum alloy, the precipitation kinetics of the composites were accelerated by adding the reinforcement. This effectively reduced the time for obtaining the maximum hardness by the aging heat treatment.

  11. Effect of fibers on Hybrid Matrix Composites

    Directory of Open Access Journals (Sweden)

    A.Manikandan

    2016-10-01

    Full Text Available Frictional co-efficient, impact quality; dielectric quality and compound resistance examination of bamboo/glass strands strengthened epoxy half breed composites were considered. Two distinctive crossover composites, for example, treated and untreated bamboo filaments were manufactured and impact of soluble base treatment of the bamboo strands on these properties were additionally concentrated on. It was watched that, effect quality and frictional co-proficient properties of the half and half composites increment with expansion in glass fiber content. These properties observed to be higher when salt treated bamboo filaments were utilized as a part of the half breed composites. It is watched that, concoction resistance was fundamentally increments for all chemicals with the exception of carbon tetrachloride. The disposal of nebulous hemi-cellulose with salt treatment prompting higher crystallinity of the bamboo filaments with antacid treatment may in charge of these perceptions. The impact of salt treatment on the holding between glass/bamboo composites was additionally concentrated on. Checking electron magnifying lens (SEM were additionally directed on the cross segments of broke surfaces with a specific end goal to rate the execution crossover composites were likewise conferred bear natural products.

  12. Experimental investigation of cyclic hygrothermal aging of hybrid composite

    KAUST Repository

    El Yagoubi, Jalal

    2013-04-05

    This work provides an experimental investigation of the cyclic hygrothermal aging of a hybrid composites. We aimed to propose a general framework in the view to further optimize polymer-based composites. It reports experimental data and relevant observations collected during an aging campaign (up to 2000 cycles) where anhydride-cured epoxy samples as well as composites samples are exposed to environmental conditions. The data gathered during the whole campaign reveals that (1) the polymer displays a non-classical sorption behavior (2) the volume change is correlated to the mass uptake (3) the elastic modulus is correlated to the glass transition temperature. Matrix and interface degradation of the hybrid composite is monitored by means of microstructural observations. © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

  13. Hybrid composites that retain graphite fibers on burning

    Science.gov (United States)

    House, E. E.

    1980-01-01

    A laboratory scale program was conducted to determine fiber release tendencies of graphite reinforced/resinous matrix composites currently used or projected for use in civil aircraft. In the event of an aircraft crash and burn situation, there is concern that graphite fibers will be released from the composites once the resin matrix is thermally decomposed. Hybridizing concepts aimed at preventing fiber release on burning were postulated and their effectiveness evaluated under fire, impact, and air flow during an aircraft crash.

  14. ASSESMENT OF SELF HEALING PROPERTY IN HYBRID FIBER POLYMERIC COMPOSITE

    OpenAIRE

    2011-01-01

    In recent years, Natural fiber reinforced composites is an emerging area in polymer technology. Fibers resulting from plants are considered a budding substitute for non-renewable synthetic fibers like glass and carbon fibers. The objective of this study is to merge the benefits of natural and synthetic fibers by developing ahybrid composite of jute and glass fibers along with self healing property to eliminate delamination without compromising the benefits of hybridization. This concept offer...

  15. Fracture behavior of hybrid composite laminates

    Science.gov (United States)

    Kennedy, J. M.

    1983-01-01

    The tensile fracture behavior of 15 center-notched hybrid laminates was studied. Three basic laminate groups were tested: (1) a baseline group with graphite/epoxy plies, (2) a group with the same stacking sequence but where the zero-deg plies were one or two plies of S-glass or Kevlar, and (3) a group with graphite plies but where the zero-deg plies were sandwiched between layers of perforated Mylar. Specimens were loaded linearly with time; load, far field strain, and crack opening displacement (COD) were monitored. The loading was stopped periodically and the notched region was radiographed to reveal the extent and type of damage (failure progression). Results of the tests showed that the hybrid laminates had higher fracture toughnesses than comparable all-graphite laminates. The higher fracture toughness was due primarily to the larger damage region at the ends of the slit; delamination and splitting lowered the stress concentration in the primary load-carrying plies. A linear elastic fracture analysis, which ignored delamination and splitting, underestimated the fracture toughness. For almost all of the laminates, the tests showed that the fracture toughness increased with crack length. The size of the damage region at the ends of the slit and COD measurements also increased with crack length.

  16. Hybrid QoS-aware semantic web service composition strategies

    Institute of Scientific and Technical Information of China (English)

    YANG FangChun; SU Sen; LI Zhen

    2008-01-01

    Hybrid QoS model which consists of certain and uncertain expressions has strong power of semantic QoS description. For solving the hybrid QoS-aware semantic web service composition problem, this paper presents an Uncertain Multi-attribute decision making based Composition algorithm (UMC). The UMC includes two parts. First, UMC-Core can be used to synthetically evaluate the hybrid service quality information. Second, UMC-DH (Distributed and Heuristic framework for UMC) aims at enhancing the run-time performance of UMC when the problem space increases. The simulation results show that the UMC has lower execution cost, higher ap proximation ratio and success ratio than other similar approaches.

  17. Synthesis of a hybrid MIL-101(Cr)/ZTC composite for hydrogen storage applications

    CSIR Research Space (South Africa)

    Musyoka, Nicholas M

    2016-06-01

    Full Text Available Metal–organic frameworks (MOFs) hybrid composites have recently attracted considerable attention in hydrogen storage applications. In this study a hybrid composite of zeolite templated carbon (ZTC) and Cr-based MOF (MIL-101) was synthesised...

  18. Metal–organic frameworks-derived honeycomb-like Co3O4/three-dimensional graphene networks/Ni foam hybrid as a binder-free electrode for supercapacitors

    DEFF Research Database (Denmark)

    Deng, Xiaoyang; Li, Jiajun; Zhu, Shan

    2017-01-01

    The honeycomb-like porous Co3O4 grown on three dimensional graphene networks/nickel foam (3DGN/NF) has been successfully prepared by a facile solution growth process with subsequent annealing treatment, in which the Co-based metal organic framework (ZIF-67) act as the precursor of the metal oxide....... The Co3O4/three-dimensional graphene networks/Ni foam (Co3O4/3DGN/NF) hybrid as the electrode for supercapacitor can deliver high specific capacitance (321 F g−1 at 1 A g−1) and excellent long-cycling stability (88% of the maximum capacitance after 2000 charge-discharge cycles). Furthermore, the Co3O4...... pseudocapacitance performance and the intimate integration of graphene with the Co3O4 and the Ni foam matrix, which not only enhances the electron conductivity for fast electron and ion transport but also provides high specific surface area and excellent structural stability....

  19. Novel hybrid coatings with controlled wettability by composite nanoparticle aggregation

    Energy Technology Data Exchange (ETDEWEB)

    Hritcu, Doina, E-mail: dhritcu@ch.tuiasi.ro; Dodi, Gianina; Iordache, Mirabela L.; Draganescu, Dan; Sava, Elena; Popa, Marcel I.

    2016-11-30

    Highlights: • Magnetite-grafted chitosan composite nanoparticles were synthesized. • The particles are able to assemble under the influence of a silane derivative. • Thin films containing composites, chitosan and hydrolyzed silane were optimized. • The novel hybrid coatings show hierarchical roughness and high wetting angle. - Abstract: The aim of this study is to evaluate novel hybrid materials as potential candidates for producing coatings with hierarchical roughness and controlled wetting behaviour. Magnetite (Fe{sub 3}O{sub 4}) nanoparticles obtained by co-precipitation were embedded in matrices synthesized by radical graft co-polymerization of butyl acrylate (BA), butyl methacrylate (BMA), hexyl acrylate (HA) or styrene (ST) with ethylene glycol di-methacrylate (EGDMA) onto previously modified chitosan bearing surface vinyl groups. The resulting composite particles were characterized regarding their average size, composition and magnetic properties. Hybrid thin films containing suspension of composite particles in ethanol and pre-hydrolysed hexadecyltrimethoxysilane (HDTS) as a coupling/crosslinking agent were deposited by spin coating or spraying. The films were cured by heating and subsequently characterized regarding their morphology (scanning electron microscopy), contact angle with water and adhesion to substrate (scratch test). The structure-property relationship is discussed.

  20. Analysis of high velocity impact on hybrid composite fan blades

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1979-01-01

    This paper describes recent developments in the analysis of high velocity impact of composite blades using a computerized capability which consists of coupling a composites mechanics code with the direct-time integration features of NASTRAN. The application of the capability to determine the linear dynamic response of an intraply hybrid composite aircraft engine fan blade is described in detail. The predicted results agree with measured data. The results also show that the impact stresses reach sufficiently high magnitudes to cause failures in the impact region at early times of the impact event.

  1. Epoxy Resin Composite Based on Functional Hybrid Fillers

    Directory of Open Access Journals (Sweden)

    Mariusz Oleksy

    2014-08-01

    Full Text Available A study was carried out involving the filling of epoxy resin (EP with bentonites and silica modified with polyhedral oligomeric silsesquioxane (POSS. The method of homogenization and the type of filler affect the functional and canceling properties of the composites was determined. The filler content ranged from 1.5% to 4.5% by mass. The basic mechanical properties of the hybrid composites were found to improve, and, in particular, there was an increase in tensile strength by 44%, and in Charpy impact strength by 93%. The developed hybrid composites had characteristics typical of polymer nanocomposites modified by clays, with a fine plate morphology of brittle fractures observed by SEM, absence of a plate separation peak in Wide Angles X-ray Scattering (WAXS curves, and an exfoliated structure observed by TEM.

  2. Novel hybrid coatings with controlled wettability by composite nanoparticle aggregation

    Science.gov (United States)

    Hritcu, Doina; Dodi, Gianina; Iordache, Mirabela L.; Draganescu, Dan; Sava, Elena; Popa, Marcel I.

    2016-11-01

    The aim of this study is to evaluate novel hybrid materials as potential candidates for producing coatings with hierarchical roughness and controlled wetting behaviour. Magnetite (Fe3O4) nanoparticles obtained by co-precipitation were embedded in matrices synthesized by radical graft co-polymerization of butyl acrylate (BA), butyl methacrylate (BMA), hexyl acrylate (HA) or styrene (ST) with ethylene glycol di-methacrylate (EGDMA) onto previously modified chitosan bearing surface vinyl groups. The resulting composite particles were characterized regarding their average size, composition and magnetic properties. Hybrid thin films containing suspension of composite particles in ethanol and pre-hydrolysed hexadecyltrimethoxysilane (HDTS) as a coupling/crosslinking agent were deposited by spin coating or spraying. The films were cured by heating and subsequently characterized regarding their morphology (scanning electron microscopy), contact angle with water and adhesion to substrate (scratch test). The structure-property relationship is discussed.

  3. Epoxy Resin Composite Based on Functional Hybrid Fillers

    Science.gov (United States)

    Oleksy, Mariusz; Szwarc-Rzepka, Karolina; Heneczkowski, Maciej; Oliwa, Rafał; Jesionowski, Teofil

    2014-01-01

    A study was carried out involving the filling of epoxy resin (EP) with bentonites and silica modified with polyhedral oligomeric silsesquioxane (POSS). The method of homogenization and the type of filler affect the functional and canceling properties of the composites was determined. The filler content ranged from 1.5% to 4.5% by mass. The basic mechanical properties of the hybrid composites were found to improve, and, in particular, there was an increase in tensile strength by 44%, and in Charpy impact strength by 93%. The developed hybrid composites had characteristics typical of polymer nanocomposites modified by clays, with a fine plate morphology of brittle fractures observed by SEM, absence of a plate separation peak in Wide Angles X-ray Scattering (WAXS) curves, and an exfoliated structure observed by TEM. PMID:28788177

  4. Mechanical performance of oil palm empty fruit bunches/jute fibres reinforced epoxy hybrid composites

    Energy Technology Data Exchange (ETDEWEB)

    Jawaid, M. [School of Industrial Technology, Universiti Sains Malaysia, 11800 Penang (Malaysia); Abdul Khalil, H.P.S., E-mail: akhalilhps@gmail.com [School of Industrial Technology, Universiti Sains Malaysia, 11800 Penang (Malaysia); Abu Bakar, A. [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2010-11-15

    Research highlights: {yields} Hybrid composites constituents of natural fibres show good mechanical performances. {yields} Hybridization with 20% jute fibre gives rise to sufficient modulus to composites. {yields} Outer or core material affect mechanical performance of hybrid composites. {yields} Impact strength of pure EFB composite is higher than hybrid composites. - Abstract: Oil palm empty fruit bunches (EFB)/jute fibre reinforced epoxy hybrid composites with different sequence of fibre mat arrangement such as EFB/jute/EFB and jute/EFB/jute were fabricated by hand lay-up method. The effect of layering patterns on the mechanical performance of the composites was studied. The hybrid composites are intended for engineering applications as an alternative to synthetic fibre composites. Mechanical performance of hybrid composites were evaluated and compared with the pure EFB, pure jute composites and neat epoxy using flexural and impact testing. The flexural properties of hybrid composite is higher than that of pure EFB composite with respect to the weight fraction of fibre, where as the impact strength of pure EFB composite is much higher than those of hybrid composites. The flexural results were interpreted using sandwich theory. The fracture surface morphology of the impact testing samples of the hybrid composites was performed by scanning electron microscopy (SEM).

  5. The cosmological principle and honeycombs

    Energy Technology Data Exchange (ETDEWEB)

    Criado, C [Departamento de Fisica Aplicada I, Universidad de Malaga, 29071 Malaga (Spain); Alamo, N [Departamento de Algebra, Geometria y Topologia, Universidad de Malaga, 29071 Malaga (Spain)

    2004-05-07

    We present the possibility that the gravitational growth of primordial density fluctuations leads to what can be considered a weak version of the cosmological principle. The large-scale mass distribution associated with this principle must have the geometrical structure known as a regular honeycomb. We give the most important parameters that characterize the honeycombs associated with the closed, open, and flat Friedmann-LemaItre-Robertson-Walker models. These parameters can be used to determine by means of observations which is the appropriate honeycomb. For each of these honeycombs, and for a nearly flat universe, we have calculated the probability that a randomly placed observer could detect the honeycomb as a function of the density parameters {omega}{sub 0} and {omega}{sub {lambda}}{sub 0}.

  6. Relative biocompatibility of micro-hybrid and nano-hybrid light-activated composite resins.

    Science.gov (United States)

    Olabisi Arigbede, Abiodun; Folasade Adeyemi, Bukola; Femi-Akinlosotu, Omowumi

    2017-01-01

    Background. In vitro studies have revealed a direct association between resin content and cytotoxicity of composite resins; however, implantation studies in this regard are sparse. This study investigates the relationship between filler content of composite resins and biocompatibility. Methods. This research employed twelve 180‒200-gr male Wistar rats, 1 nano-hybrid (Prime-Dent Inc.) and 1 micro-hybrid (Medental Inc.) composite resins containing 74% and 80‒90% filler content, respectively. The samples were assessed on the 2nd, 14th and 90th day of implantation. Four rats were allocated to each day in this experimental study. A section of 1.5mm long cured nano-hybrid and micro-hybrid materials were implanted into the right and left upper and lower limbs of the rats, respectively. Eight samples were generated on each day of observation. Inflammation was graded according to the criteria suggested by Orstavik and Major. Pearson's chi-squared test was employed to determine the relationship between the tissue responses of the two materials. Statistical significance was set at P composite resins with higher filler content elicited a significantly lower grade of inflammation irrespective of the duration (χ=20.000, df=8, P=0.010) while the composite resins with lower filler content elicited a significantly lower inflammatory response on the 90th day (χ=4.000, df=1, P=0.046). Conclusion. The composite resins with higher filler content generally elicited significantly lower grades of inflammation, and the composite resins with lower filler content exhibited significantly lower inflammatory response on the 90th day of implantation.

  7. Strong and light-weight materials made of reinforced honeycomb sandwich structures

    DEFF Research Database (Denmark)

    Mikkelsen, Lars Pilgaard; Madsen, Bo

    a low cost, in order for them to compete with conventionally used materials like steel or aluminum. A great candidate for a material that can fulfil these requirements of being light, strong and low cost is a sandwich material. A sandwich material is a material that is made of a light-weight core...... with a thin layer of steel or fibre composite on top and bottom of the core. The core in a sandwich material is typically made of a honeycomb structure. Honeycomb structures have been used for more than 50 years. Until now honeycombs have been expensive to produce. However, with a new production method...... it is now possible to produce honeycombs structures at a low cost. In a large collaborative European project called INCOM, the possibility of reinforcing the honeycomb structure is investigated. The honeycomb structure is reinforced with sustainable fibres as the fibres are extracted from saw dust....

  8. THE SYNERGISTIC EFFECT OF HYBRID FLAME RETARDANTS ON PYROLYSIS BEHAVIOUR OF HYBRID COMPOSITE MATERIALS

    Directory of Open Access Journals (Sweden)

    M. T. ALBDIRY

    2012-06-01

    Full Text Available The aim of this investigation is to comprehensively understand the polymeric composite behavior under direct fire sources. The synergistic effects of hybrid flame retardant material on inhabiting the pyrolysis of hybrid reinforced fibers, woven roving (0°- 45° carbon and kevlar (50/50 wt/wt, and an araldite resin composites were studied. The composites were synthesised and coated primarily by zinc borate (2ZnO.3B2O3.3.5H2O and modified by antimony trioxide (Sb2O3 with different amounts (10-30 wt% of flame retardant materials. In the experiments, the composite samples were exposed to a direct flame source generated by oxyacetylene flame (~3000ºC at variable exposure distances of 10-20 mm. The synergic flame retardants role of antimony trioxide and zinc borate on the composite surface noticeably improves the flame resistance of the composite which is attributed to forming a protective mass and heat barrier on the composite surface and increasing the melt viscosity.

  9. Hybrid fiber reinforcement and crack formation in Cementitious Composite Materials

    DEFF Research Database (Denmark)

    Pereira, E.B.; Fischer, Gregor; Barros, J.A.O.

    2011-01-01

    reinforcement systems. The research described in this paper shows that the multi-scale conception of cracking and the use of hybrid fiber reinforcements do not necessarily result in an improved tensile behavior of the composite. Particular material design requirements may nevertheless justify the use of hybrid......The use of different types of fibers simultaneously for reinforcing cementitious matrices is motivated by the concept of a multi-scale nature of the crack propagation process. Fibers with different geometrical and mechanical properties are used to bridge cracks of different sizes from the micro......- to the macroscale. In this study, the performance of different fiber reinforced cementitious composites is assessed in terms of their tensile stress-crack opening behavior. The results obtained from this investigation allow a direct quantitative comparison of the behavior obtained from the different fiber...

  10. Tensile Fracture Mechanism of Claviform Hybrid Composite Rebar

    Institute of Scientific and Technical Information of China (English)

    CAI Lurong; ZENG Qingdun; WANG Ronghui

    2012-01-01

    Based on the shear-lag theory,a hexagonal model of fiber bundles was established to study the tensile fracture mechanism of a claviform hybrid composite rebar.Firstly,the stress redistributions are investigated on two conditions:one condition is that interfacial damage is taken into accotmt and the other is not.Then,a micro-statistical analysis of the multiple tensile failures of the rebar was performed by using the random critical-core theory.The results indicate that the predictions of the tensile failure strains of the rebar,in which the interracial damage is taken into account,are in better agreement with the existing experimental results than those when only elastic case is considered.Through the comparison between the theoretical and experimental results,the shear-lag theory and the model are verified feasibly in studying the claviform hybrid composite rebar.

  11. Synthesis and Characterization of Novel Epoxy Geopolymer Hybrid Composites

    Directory of Open Access Journals (Sweden)

    Oreste Tarallo

    2013-09-01

    Full Text Available The preparation and the characterization of novel geopolymer-based hybrid composites are reported. These materials have been prepared through an innovative synthetic approach, based on a co-reticulation in mild conditions of commercial epoxy based organic resins and a metakaolin-based geopolymer inorganic matrix. This synthetic strategy allows the obtainment of a homogeneous dispersion of the organic particles in the inorganic matrix, up to 25% in weight of the resin. The materials obtained present significantly enhanced compressive strengths and toughness with respect to the neat geopolymer, suggesting their wide utilization for structural applications. A preliminary characterization of the porous materials obtained by removing the organic phase from the hybrid composites by means of heat treatments is also reported. Possible applications of these materials in the field of water purification, filtration, or as lightweight insulating materials are envisaged.

  12. STUDY ON STRESS CONCENTRATIONS IN AN INTRAPLY HYBRID COMPOSITE SHEET

    Institute of Scientific and Technical Information of China (English)

    曾庆敦; 黄小清; 林雪慧

    2001-01-01

    A reasonably, simply and accurately modified shear-lag model was proposed.Based on the model, the stress redistributions due to the failure of some fibers in an intraply hybrid composite under tension were analyzed. The results show that the present calculating stress concentration factors very coincide with Fukuda and Chou' s results, thus verifying the reasonableness and correctness of the present model and methods.

  13. Experiments on a Hybrid Composite Beam for Bridge Applications

    OpenAIRE

    Van Nosdall, Stephen Paul

    2013-01-01

    This thesis details a study of the structural behavior of Hybrid-Composite Beams (HCB) consisting of a fiber reinforced polymer (FRP) shell with a concrete arch tied with steel prestressing strands.  The HCB offers advantages in life cycle costs through reduced transportation weight and increased corrosion resistance. By better understanding the system behavior, the proportion of load in each component can be determined, and each component can be designed for the appropriate forces. A long te...

  14. Mechanical Properties of Coir Rope-Glass Fibers Reinforced Polymer Hybrid Composites

    Directory of Open Access Journals (Sweden)

    B.Bakri

    2015-10-01

    Full Text Available Natural fiber composites have been developed and taken more attention in the last decades. Coir fiber is the natural fiber which has been used as reinforcement of composites. This fiber is hybridized with glass fiber for reinforcement composite. In this paper, coir rope and glass fibers were combined as reinforcement into hybrid composites with unsaturated polyester resin as matrix. The composition of fibers and matrix into hybrid composites are used 30:70 (volume fraction with unsaturated polyester. Volume fractions of coir rope mat and glass fiber mat in hybrid composites are 10:20, 15:15 and 20:10 respectively. The mechanical properties of the coir rope-glass fiber composite hybrid were described in this paper. Their properties include tensile strength, tensile modulus, flexural strength, flexural modulus, impact energy and impact strength. Fractography of tensile composite hybrid is also analyzed using Scanning Electron Microscope.

  15. 复合材料蜂窝夹芯板低速冲击损伤研究%Studies on Low-velocity Impact damage of Composite Honeycomb Sandwich Panel

    Institute of Scientific and Technical Information of China (English)

    李进亚; 许希武; 毛春见

    2012-01-01

    A 3D dynamic finite element model is proposed to predict the progressive damage of composites honeycomb core sandwich due to low impact. The core of this model was equivalent to a uniform orthogonal anisotropic materials. This model consists of Hashin damage criterion and Yeh failure criterion for face-plate, and deg-radate the material property which is damaged. Combined with the user-defined material constitutive program of Abaqus , the failure criterion and degra dation of material property are simulated . The dynamic response and dam-age propagation of comp osites honeycomb core sandwich due to low impact were simulated with this method. The numerical results is compared with the experiment results, it prove that the method was reasonable. The effects of the parameters on the dynamic response and damage evolution of composites honeycomb core sandwich are discussed in this paper.%通过三维动力学有限元建立了复合材料蜂窝夹芯板在低速冲击作用下的渐进损伤分析模型.该模型中将蜂窝夹芯等效为均匀的正交各项异性材料.采用基于应变的Hashin三维失效准则和Yeh分层失效准则对面板损伤进行判断.使用部分刚度折减对损伤材料性能进行退化.利用用户子程序将损伤判据和刚度折减方案引入到ABAQUS软件中.模拟了复合材料蜂窝夹芯板低速冲击损伤渐进过程,并与试验结果进行验证.证明了该方法的合理性,最后讨论了各种参数对冲击响应和冲击损伤的影响.

  16. Sound Insulation Property of the Composite Structure with Micro-perforated Panels and Honeycomb Core%微穿孔板--蜂窝夹芯复合结构的隔声性能

    Institute of Scientific and Technical Information of China (English)

    杨军伟; 蔡俊; 邵骢

    2013-01-01

    对微穿孔板和铝蜂窝芯的复合结构,测定其具有不同参数的隔声性能。在该结构中加入GSGN薄膜和木屑板,制备出新型轻质隔声复合结构板,计权隔声量为58.41 dB,密度仅为0.037 g/mm3,达到了轻质高效隔声的目的。预期该新型复合结构板可应用于建筑材料和声屏障上,可提高结构的隔声降噪能力,改善居民生活环境质量。%A new type of light sound-insulation composite plates made up of aluminum honeycomb core and micro-perforated panels with GSGN film and sawdust-board added in was fabericated. The sound insulation properties of the plates with different structural parameters of the honeycomb cores and microperforated panels were measured. The result shows that the weighted sound-insulation index can reach 58.41 dB and the density is only 0.37 g/mm3. It is expected that the traffic noise can be greatly reduced if these composite structures are applied to the sound barriers, and the quality of acoustic environment can be greatly improved.

  17. Influences of Cutting Tool Load on Impedance Characteristics of Honeycomb Composite Material Ultrasonic Cutting Acoustic System%刀具负载对蜂窝复合材料超声切割声学系统阻抗特性的影响

    Institute of Scientific and Technical Information of China (English)

    纪华伟; 虞文泽; 胡小平; 于保华

    2016-01-01

    针对刀具负载对蜂窝复合材料超声切割声学系统的影响,利用四端网络法,将压电换能器与变幅杆结合在一起,提出了声学系统的整体设计方程,得出了负载与声学系统阻抗特性的关系式。利用有限元软件对声学系统进行模态分析及谐响应分析,并利用阻抗分析仪和激光位移传感器对声学系统的阻抗﹑谐振频率和输出振幅进行检测。仿真和实验结果表明:随着刀具负载的增大,声学系统的阻抗值增大,谐振频率减小,但仿真与实验得出的输出振幅与理论分析不同,这是由于刀具的放大作用造成的。研究结果对声学系统的设计及实际应用有指导意义。%The impedance characteristics of a honeycomb composite material ultrasonic cutting a-coustic system varied with the cutting tool load.By combing piezoelectric transducer with horn,a hy-brid design equation of the acoustic system was put forward based on four-terminal network,and the relationship between load and the impedance characteristics of acoustic system was obtained.The mo-dal analysis and the harmonic response analysis to the acoustic system were carried on by using of the finite element software and the impedance,resonant frequency and output amplitude of the acoustic system were measured by the impedance analyzer and laser displacement sensor.Simulation and ex-perimental results show that the impedance of the acoustic system is increased,and the resonance fre-quency decreases with the increase of the tool load,but the output amplitudes among theoretical anal-ysis,simulation and experiment are different,which is due to the amplification of the tool.The study has a guiding significance for the design and applications of honeycomb composite material ultrasonic cutting acoustic system.

  18. Woven hybrid composites: Tensile and flexural properties of oil palm-woven jute fibres based epoxy composites

    Energy Technology Data Exchange (ETDEWEB)

    Jawaid, M. [School of Industrial Technology, Universiti Sains Malaysia, 11800 Penang (Malaysia); Abdul Khalil, H.P.S., E-mail: akhalilhps@gmail.com [School of Industrial Technology, Universiti Sains Malaysia, 11800 Penang (Malaysia); Abu Bakar, A. [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2011-06-15

    Highlights: {yields} Woven hybrid composites show good tensile and flexural properties. {yields} Hybridization with 20% woven jute gives rise to sufficient modulus to composites. {yields} Layering pattern affect mechanical properties of hybrid composites. {yields} Statistical analysis shows that there is significant difference between composites. - Abstract: In this research, tensile and flexural performance of tri layer oil palm empty fruit bunches (EFB)/woven jute (Jw) fibre reinforced epoxy hybrid composites subjected to layering pattern has been experimentally investigated. Sandwich composites were fabricated by hand lay-up technique in a mould and cured with 105 deg. C temperatures for 1 h by using hot press. Pure EFB and woven jute composites were also fabricate for comparison purpose. Results showed that tensile and flexural properties of pure EFB composite can be improved by hybridization with woven jute fibre as extreme woven jute fibre mat. It was found that tensile and flexural properties of hybrid composite is higher than that of EFB composite but less than woven jute composite. Statistical analysis of composites done by ANOVA-one way, it showed significant differences between the results obtained. The fracture surface morphology of the tensile samples of the hybrid composites was performed by using scanning electron microscopy.

  19. Genome composition of 'Elatior'-begonias hybrids analyzed by genomic in situ hybridisation

    NARCIS (Netherlands)

    Marasek Ciolakowska, A.R.; Ramanna, M.S.; Laak, W.A.; Tuyl, van J.M.

    2010-01-01

    Interspecific hybridization of various tuberous Begonia species hybrids with Begonia socotrana results in so-called 'Elatior'-begonias hybrids (B. x hiemalis Fotsch). In our study, genomic in situ hybridization (GISH) has been employed to assess the genome composition in eleven 'Elatior'-begonias

  20. On the development of an intrinsic hybrid composite

    Science.gov (United States)

    Kießling, R.; Ihlemann, J.; Riemer, M.; Drossel, W.-G.; Scharf, I.; Lampke, T.; Sharafiev, S.; Pouya, M.; F-X Wagner, M.

    2016-03-01

    Hybrid parts, which combine low weight with high strength, are moving into the focus of the automotive industry, due to their high potential for usage in the field of crash-relevant structures. In this contribution, the development of an intrinsic hybrid composite is presented, with a focus on the manufacturing process, complex simulations of the material behaviour and material testing. The hybrid composite is made up of a continuous fibre- reinforced plastic (FRP), in which a metallic insert is integrated. The mechanical behaviour of the individual components is characterised. For material modelling, an approach is pointed out that enables modelling at large strains by directly connected rheological elements. The connection between the FRP and the metallic insert is realised by a combination of form fit and adhesive bonds. On the one hand, adhesive bonds are generated within a sol gel process. On the other hand, local form elements of the metallic insert are pressed into the FRP. We show how these form elements are generated during the macroscopic forming process. In addition, the applied sol gel process is explained. Finally, we consider design concepts for a specimen type for high strain testing of the resulting interfaces.

  1. Photoresponsive Self-Healing Polymer Composite with Photoabsorbing Hybrid Microcapsules.

    Science.gov (United States)

    Gao, Lei; He, Jinliang; Hu, Jun; Wang, Chao

    2015-11-18

    Microcapsule-based self-healing polymer materials are highly desirable because they can heal large-volume cracks without changing the original chemical structures of polymers. However, they are limited by processing difficulties and inhomogeneous distributions of two components. Herein, we report a one-component photoresponsive self-healing polymer composite with photoabsorbing hybrid microcapsules (PAHM), which gives the microcapsules photoabsorbing properties by introducing nano-TiO2 particles as photoabsorbing and emulsified agents in the poly(urea-formaldehyde)/TiO2 hybrid shells. Upon mechanical damage and then exposure to light, the photoresponsive healing agents in the cracks will be solidified to allow for self-healing, while the healing agents in the unbroken PAHM will be protected and remain unreacted, which endows this photoresponsive microcapsule-based self-healing composite with self-healing properties like those found in the conventional two-component microcapsule-based systems. Given the universality of this hybrid polymerization method, incorporation of the photoabsorbing particles to conventional polymer shells may further broaden the scope of applications of these widely used materials.

  2. Volumetric composition and shear strength evaluation of pultruded hybrid kenaf/glass fiber composites

    DEFF Research Database (Denmark)

    Hashemi, Fariborz; Tahir, Paridah Md; Madsen, Bo

    2015-01-01

    In the present study, six different combinations of pultruded hybrid kenaf/glass composites were fabricated. The number of kenaf and glass rovings was specifically selected to ensure constant local fiber volume fractions in the composites. The volumetric composition of the composites was determined...... by using a gravimetrically based method. Optical microscopy was used to determine the location of voids. The short-beam test method was used to determine the interlaminar shear strength of the composites, and the failure mode was observed. It was found that the void volume fraction of the composites...... was increased as a function of the kenaf fiber volume fraction. A linear relationship with high correlation (R2=0.95) was established between the two volume fractions. Three types of voids were observed in the core region of the composites (lumen voids, interface voids and impregnation voids). The failure...

  3. Ablation Performance of a Novel Super-hybrid Composite

    Institute of Scientific and Technical Information of China (English)

    Jun QIU; Xiaoming CAO; Chong TIAN; Jinsong ZHANG

    2005-01-01

    A novel super-hybrid composite (NSHC) was boron-modified phenolic resin (BPR) with three-dimensional reticulated SiC ceramic (3DRC) and high silica fibers. Ablation performance of the NSHC was studied. The results show that the linear ablation rate of NSHC was lower than that of pure BPR and the high silica/BPR composite. Its linear ablation rate is 1/17 of the high silica/BPR. Mass ablation rate of the NSHC is very close to that of the pure BPR and the high silica/BPR composite. Scanning electron microscope (SEM) analysis indicates that 3DRC has scarcely changed its shape at the ablation temperature. Its special reticulated structure can restrict the materials deformation and prevent high velocity heat flow from eroding the surface of the materials largely and thus increase ablation resistance of the NSHC.

  4. Hybrid Titanium Composite Laminates: A New Aerospace Material

    Science.gov (United States)

    Johnson, W. S.; Cobb, Ted Q.; Lowther, Sharon; St.Clair, T. L.

    1998-01-01

    In the realm of aerospace design and performance, there are few boundaries in the never-ending drive for increased performance. This thirst for ever-increased performance of aerospace equipment has driven the aerospace and defense industries into developing exotic, extremely high-performance composites that are pushing the envelope in terms of strength-to-weight ratios, durability, and several other key measurements. To meet this challenge of ever-increasing improvement, engineers and scientists at NASA-Langley Research Center (NASA-LaRC) have developed a high-temperature metal laminate based upon titanium, carbon fibers, and a thermoplastic resin. This composite, known as the Hybrid Titanium Composite Laminate, or HTCL, is the latest chapter in a significant, but relatively short, history of metal laminates.

  5. Low and high velocity impact response of thick hybrid composites

    Science.gov (United States)

    Hiel, Clement; Ishai, Ori

    1993-01-01

    The effects of low and high velocity impact on thick hybrid composites (THC's) were experimentally compared. Test Beams consisted of CFRP skins which were bonded onto an interleaved syntactic foam core and cured at 177 C (350 F). The impactor tip for both cases was a 16 mm (0.625 inch) steel hemisphere. In spite of the order of magnitude difference in velocity ranges and impactor weights, similar relationships between impact energy, damage size, and residual strength were found. The dependence of the skin compressive strength on damage size agree well with analytical open hole models for composite laminates and may enable the prediction of ultimate performance for the damaged composite, based on visual inspection.

  6. 复合材料蜂窝板脉冲热像检测和调制热像检测的比较研究%Comparative study on pulsed thermography and modulated thermography of composite honeycomb panels

    Institute of Scientific and Technical Information of China (English)

    郭兴旺; 许文浩

    2012-01-01

    为了探索适合复合材料蜂窝板缺陷检测的红外热像检测法及热像信号处理方法,对蜂窝板的脉冲热像检测(PT)、调制热像检测(MT)及几种热像信号处理方法的缺陷检测能力进行了比较。在脉冲热像检测中,用脉冲相位法进行热像序列处理,并与最佳原始热像进行比较。在调制热像检测中,提出用离散傅里叶级数法和相关系数法进行热像序列处理,并与经典的四点法进行比较。研究结果表明,在蜂窝板脱粘缺陷的检测中,调制热像法的检测效果好于脉冲热像法。在调制热像法的信号处理中,离散傅里叶级数法和相关系数法的应用效果均好于四点法。在最佳调制频率下,以"调制热像-离散傅里叶级数"法进行蜂窝板脱粘缺陷的检测具有最大的缺陷探测能力。%To investigate the optimal infrared thermography testing technique and thermographic data processing methods for the flaw inspection of composite honeycomb panels,the defect detection capabilities of pulsed thermography(PT),modulated thermography(MT) and several thermographic data processing algorithms were compared.In PT,pulsed phase thermography(PPT) was applied to the thermographic signal processing,and compared with the best raw image.In MT,discrete Fourier series(DFS) and correlation coefficient(CC) algorithm were newly proposed to process the experimental data,and compared with the classical Four-point method.The obtained results indicate that,MT is better than PT for debonding inspection of honeycomb panels.The effects of both DFS and CC are better than Four-point method for signal processing of MT.At the best modulation frequency,the MT-DFS method shows the maximum detection capability for debondings in honeycomb panels.

  7. Adaptive, Active and Multifunctional Composite and Hybrid Materials Program: Composite and Hybrid Materials ERA

    Science.gov (United States)

    2014-04-01

    16 4.2.4.3 Fabrication and Modeling of Rubber Muscle Actuators ..........17 4.2.4.4 Modeling of Power Response of SMP/SMA...Processing of BMI/Preceramic Polymer Blends .................................28 4.9 Task 9.0 Hybrid Material Processing and Fabrication...electrical stimulus, similar in action to the natural response of the conformation of a bird wing during flight vs. takeoff or landing, a muscle pair

  8. Evaluation of hybrid composite materials in cylindrical specimen geometries

    Science.gov (United States)

    Liber, T.; Daniel, I. M.

    1976-01-01

    Static and fatigue properties of three composite materials and hybrids were examined. The materials investigated were graphite/epoxy, S-glass/epoxy, PRD-49 (Kevlar 49)/epoxy, and hybrids in angle-ply configurations. A new type of edgeless cylindrical specimen was developed. It is a flattened tube with two flat sides connected by curved sections and it is handled much like the standard flat coupon. Special specimen fabrication, tabbing, and tab region reinforcing techniques were developed. Axial modulus, Poisson's ratio, strength, and ultimate strain were obtained under static loading from flattened tube specimens of nine laminate configurations. In the case of graphite/epoxy the tubular specimens appeared to yield somewhat higher strength and ultimate strain values than flat specimens. Tensile fatigue tests were conducted with all nine types of specimens and S-N curves obtained. Specimens surviving 10 million cycles of tensile loading were subsequently tested statically to failure to determine residual properties.

  9. Fabrication and adsorption properties of hybrid fly ash composites

    Science.gov (United States)

    Gao, Mengfan; Ma, Qingliang; Lin, Qingwen; Chang, Jiali; Ma, Hongzhu

    2017-02-01

    In order to realize the utilization of fly ash (FA) as industrial solid waste better, high-efficient inorganic/organic hybrid composite adsorbents derived from (Ca(OH)2/Na2FeO4) modified FA (MF) was fabricated. The hydrophilic cationic polymer (P(DMDAAC-co-AAM) or hydrophobic modifier (KH-570) were used. The prepared composites were characterized by X-ray fluorescence spectroscopy, energy dispersive spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller, Fourier transform infrared spectroscopy, thermogravimetry, and contact angle test. The adsorption of cationic composites MF/P(DMDAAC-co-AAM) towards Orange II in wastewater was investigated. The results show that: adsorption amount of 24.8 mg/g with 2000 mg/L of composites, 50 mg/L Orange II, original pH (6-8), at 40 min and room temperature, was obtained. Meanwhile, oil adsorption ratio Q(g/g) of hydrophobic composites MF/KH-570 was also evaluated. The maximum Q of 17.2 g/g to kerosene was obtained at 40 min. The isotherm and kinetics of these two adsorption processes were also studied. The results showed that the fabricated MF composites modified with hydrophilic or hydrophobic group can be used to adsorb dye in wastewater or oil effectively.

  10. Impact of non-hookean behaviour on mechanical performance of hybrid composites

    DEFF Research Database (Denmark)

    Markussen, Christen Malte; Madsen, Bo; Lilholt, Hans

    2015-01-01

    Hybrid composites, based on unidirectional fibres of carbon and glass, in an epoxy matrix have been used to investigate the possibility of a hybrid effect. The hybrid effect is observed experimentally by values for both composite strength and composite failure strain, which are increased compared...... data. For the present hybrid composites a value of 푯 = ퟏ.ퟐퟐ is required, meaning a positive hybrid effect on “fibre” strain of 22%. It is thus concluded that the simple concept of a hybrid factor H for the fibre failure strain can describe the observed hybrid effect satisfactorily....... to a simple model. The introduction of an increase of the failure strain of the carbon fibre part (the “fibre”) of the composite, described by a factor H for the increase of the failure strain, results in theoretical curves for strength and failure strain, which are in general agreement with the experimental...

  11. MoSi2-Base Hybrid Composites from Aeroengine Applications

    Science.gov (United States)

    Hebsur, Mohan G.

    2000-01-01

    Addition of about 30 to 50 vol % of Si3N4 particulate to MoSi2 improved low temperature accelerated oxidation resistance by forming a Si2ON2 protective scale and thereby eliminated catastrophic 'pest failure'. The Si3N4 addition also improved the high temperature creep strength by nearly five orders of magnitude, doubled the room temperature toughness, and significantly lowered the CTE of the MoSi2 which eliminated matrix cracking in SCS-6 reinforced composites even after thermal cycling. The SCS-6 fiber reinforcement improved the room temperature fracture toughness by seven times and impact resistance by five times. The composite exhibited this excellent strength and toughness improvement up to 1673 K. More recently, tape casting was adopted as the preferred processing of MoSi2-base composites due to improved fiber spacing, ability to use small diameter fibers, and for lower cost. Good strength and toughness values were also obtained with fine diameter Hi-Nicalon tow fibers. These hybrid composites remain competitive with ceramic matrix composites as a replacement for Ni-base superalloys in aircraft engine applications.

  12. Mechanical and electrical performance of Roystonea regia/glass fibre reinforced epoxy hybrid composites

    Indian Academy of Sciences (India)

    Govardhan Goud; R N Rao

    2012-08-01

    The present paper investigates mechanical and electrical properties of Roystonea regia/glass fibre reinforced epoxy hybrid composites. Five varieties of hybrid composites have been prepared by varying the glass fibre loading. Roystonea regia (royal palm), a natural fibre was collected from the foliage of locally available royal palm tree through the process of water retting and mechanical extraction. Roystonea regia, -glass short fibres were used together as reinforcement in epoxy matrix to form hybrid composites. It has been observed that tensile, flexural, impact and hardness properties of hybrid composites considerably increased with increase in glass fibre loading. But electrical conductivity and dielectric constant values decreased with increase in glass fibre content in the hybrid composites at all frequencies. Scanning electron microscopy of fractured hybrid composites has been carried out to study the fibre matrix adhesion.

  13. SMA Hybrid Composites for Dynamic Response Abatement Applications

    Science.gov (United States)

    Turner, Travis L.

    2000-01-01

    A recently developed constitutive model and a finite element formulation for predicting the thermomechanical response of Shape Memory Alloy (SMA) hybrid composite (SMAHC) structures is briefly described. Attention is focused on constrained recovery behavior in this study, but the constitutive formulation is also capable of modeling restrained or free recovery. Numerical results are shown for glass/epoxy panel specimens with embedded Nitinol actuators subjected to thermal and acoustic loads. Control of thermal buckling, random response, sonic fatigue, and transmission loss are demonstrated and compared to conventional approaches including addition of conventional composite layers and a constrained layer damping treatment. Embedded SMA actuators are shown to be significantly more effective in dynamic response abatement applications than the conventional approaches and are attractive for combination with other passive and/or active approaches.

  14. Experimental Validation of a Thermoelastic Model for SMA Hybrid Composites

    Science.gov (United States)

    Turner, Travis L.

    2001-01-01

    This study presents results from experimental validation of a recently developed model for predicting the thermomechanical behavior of shape memory alloy hybrid composite (SMAHC) structures, composite structures with an embedded SMA constituent. The model captures the material nonlinearity of the material system with temperature and is capable of modeling constrained, restrained, or free recovery behavior from experimental measurement of fundamental engineering properties. A brief description of the model and analysis procedures is given, followed by an overview of a parallel effort to fabricate and characterize the material system of SMAHC specimens. Static and dynamic experimental configurations for the SMAHC specimens are described and experimental results for thermal post-buckling and random response are presented. Excellent agreement is achieved between the measured and predicted results, fully validating the theoretical model for constrained recovery behavior of SMAHC structures.

  15. Structural Acoustic Response of Shape Memory Alloy Hybrid Composite Panels

    Science.gov (United States)

    Turner, Travis L.

    1996-01-01

    A method has been developed to predict the structural acoustic response of shape memory alloy hybrid composite panels subjected to acoustic excitation. The panel is modeled by a finite element analysis and the radiated field is predicted using Rayleigh's integral. Transmission loss predictions for the case of an aluminum panel excited by a harmonic acoustic pressure are shown to compare very well with a classical analysis. Predictions of the normal velocity response and transmitted acoustic pressure for a clamped aluminum panel show excellent agreement with experimental measurements. Predicted transmission loss performance for a composite panel with and without shape memory alloy reinforcement are also presented. The preliminary results demonstrate that the transmission loss can be significantly increased with shape memory alloy reinforcement.

  16. Nonlinear Thermoelastic Model for SMAs and SMA Hybrid Composites

    Science.gov (United States)

    Turner, Travis L.

    2004-01-01

    A constitutive mathematical model has been developed that predicts the nonlinear thermomechanical behaviors of shape-memory-alloys (SMAs) and of shape-memory-alloy hybrid composite (SMAHC) structures, which are composite-material structures that contain embedded SMA actuators. SMAHC structures have been investigated for their potential utility in a variety of applications in which there are requirements for static or dynamic control of the shapes of structures, control of the thermoelastic responses of structures, or control of noise and vibrations. The present model overcomes deficiencies of prior, overly simplistic or qualitative models that have proven ineffective or intractable for engineering of SMAHC structures. The model is sophisticated enough to capture the essential features of the mechanics of SMAHC structures yet simple enough to accommodate input from fundamental engineering measurements and is in a form that is amenable to implementation in general-purpose structural analysis environments.

  17. Flexural analysis of palm fiber reinforced hybrid polymer matrix composite

    Science.gov (United States)

    Venkatachalam, G.; Gautham Shankar, A.; Raghav, Dasarath; Santhosh Kiran, R.; Mahesh, Bhargav; Kumar, Krishna

    2015-07-01

    Uncertainty in availability of fossil fuels in the future and global warming increased the need for more environment friendly materials. In this work, an attempt is made to fabricate a hybrid polymer matrix composite. The blend is a mixture of General Purpose Resin and Cashew Nut Shell Liquid, a natural resin extracted from cashew plant. Palm fiber, which has high strength, is used as reinforcement material. The fiber is treated with alkali (NaOH) solution to increase its strength and adhesiveness. Parametric study of flexure strength is carried out by varying alkali concentration, duration of alkali treatment and fiber volume. Taguchi L9 Orthogonal array is followed in the design of experiments procedure for simplification. With the help of ANOVA technique, regression equations are obtained which gives the level of influence of each parameter on the flexure strength of the composite.

  18. Buckling induced delamination of graphene composites through hybrid molecular modeling

    Science.gov (United States)

    Cranford, Steven W.

    2013-01-01

    The efficiency of graphene-based composites relies on mechanical stability and cooperativity, whereby separation of layers (i.e., delamination) can severely hinder performance. Here we study buckling induced delamination of mono- and bilayer graphene-based composites, utilizing a hybrid full atomistic and coarse-grained molecular dynamics approach. The coarse-grain model allows exploration of an idealized model material to facilitate parametric variation beyond any particular molecular structure. Through theoretical and simulation analyses, we show a critical delamination condition, where ΔD∝kL4, where ΔD is the change in bending stiffness (eV), k the stiffness of adhesion (eV/Å4), and L the length of the adhered section (Å).

  19. Mechanical Characterization of Bio-Char Made Hybrid Composite

    Directory of Open Access Journals (Sweden)

    Amit pandey

    2016-08-01

    Full Text Available Material discoveries and development have always been the cause of the growth and development of a nation and the need of naturally made materials is the need of hours. Thus this paper takes you to the development of a hybrid composite made of sisal fiber with epoxy as the matrix intertwined with softwood bio-char. Softwood chip bio-char, produced by slow pyrolysis, has a porous structure improving its nutrient absorbing capacity, surface area and thus a potential substituent. Bio-char has an appreciable carbon sequestration value i.e. a carbon absorbing product. The orientation of sisal fiber are changed and studied in longitudinal and orthogonal direction indicating superiority of longitudinal fiber orientation .It also addresses the variation in mechanical characteristic (tensile flexural and impact with different constituent of the new composite and its position in material selection charts with a direction for further work.

  20. Influence of Material Distribution on Impact Resistance of Hybrid Composites

    Science.gov (United States)

    Abatan, Ayu; Hu, Hurang

    1998-01-01

    Impact events occur in a wide variety of circumstances. A typical example is a bullet impacting a target made of composite material. These impact events produce time-varying loads on a structure that can result in damage. As a first step to understanding the damage resistance issue in composite laminates, an accurate prediction of the transient response during an impact event is necessary. The analysis of dynamic loadings on laminated composite plates has undergone considerable development recently. Rayleigh-Ritz energy method was used to determine the impact response of laminated plates. The impact response of composite plates using shear deformation plate theory was analyzed. In recent work a closed-form solution was obtained for a rectangular plate with four edges simply supported subjected to a center impact load using classical plate theory. The problem was further investigated and the analysis results compared of both classical plate theory and shear deformation theory, and found that classical plate theory predicts very accurate results for the range of small deformations considered. In this study, the influence of cross sectional material distribution on the comparative impact responses of hybrid metal laminates subjected to low and medium velocity impacts is investigated. A simple linear model to evaluate the magnitude of the impact load is proposed first, and it establishes a relation between the impact velocity and the impact force. Then a closed-form solution for impact problem is presented. The results were compared with the finite element analysis results. For an 11 layer-hybrid laminate, the impact response as a function of material distribution in cross-section is presented. With equal areal weight, the effect of the number of laminate layers on the impact resistance is also investigated. Finally, the significance of the presented results is discussed.

  1. 蜂窝型双金属复合锤头铸造工艺%Casting Technology of Honeycomb-type Bimetallic Composite Hammer

    Institute of Scientific and Technical Information of China (English)

    王华

    2012-01-01

    Aimed at the failure characteristics of the hammer used in counterattack-type crusher due to wear, a type of honeycomb-type bimetallic hammer was developed. The hammer was made by taking high manganese steel as the hammer body and high chromium cast iron as the wear-rods, and using a special insert-cast process to inserting the wear rods into the end of the hammer. The wear rods and the hammer body have a solid combination and strong impact, improving its life of hammer, reducing the use cost ofhammer.%针对反击式破碎机专用锤头因磨损而失效的特点,研发了一种蜂窝型双金属复合型锤头.该锺头以高锰钢作锤体,高铬铸铁作耐磨棒,并采用特殊镶铸工艺,将耐磨棒弥散分布于锤头端部.锤头内耐磨棒与基体结合牢固、抗冲击能力强,大幅度提高了锤头使用寿命,从而降低了锤头综合使用成本.

  2. Advanced Ceramic Matrix Composites with Multifunctional and Hybrid Structures

    Science.gov (United States)

    Singh, Mrityunjay; Morscher, Gregory N.

    2004-01-01

    Ceramic matrix composites are leading candidate materials for a number of applications in aeronautics, space, energy, and nuclear industries. Potential composite applications differ in their requirements for thickness. For example, many space applications such as "nozzle ramps" or "heat exchangers" require very thin (structures whereas turbine blades would require very thick parts (> or = 1 cm). Little is known about the effect of thickness on stress-strain behavior or the elevated temperature tensile properties controlled by oxidation diffusion. In this study, composites consisting of woven Hi-Nicalon (trademark) fibers a carbon interphase and CVI SiC matrix were fabricated with different numbers of plies and thicknesses. The effect of thickness on matrix crack formation, matrix crack growth and diffusion kinetics will be discussed. In another approach, hybrid fiber-lay up concepts have been utilized to "alloy" desirable properties of different fiber types for mechanical properties, thermal stress management, and oxidation resistance. Such an approach has potential for the C(sub I)-SiC and SiC(sub f)-SiC composite systems. CVI SiC matrix composites with different stacking sequences of woven C fiber (T300) layers and woven SiC fiber (Hi-Nicalon (trademark)) layers were fabricated. The results will be compared to standard C fiber reinforced CVI SiC matrix and Hi-Nicalon reinforced CVI SiC matrix composites. In addition, shear properties of these composites at different temperatures will also be presented. Other design and implementation issues will be discussed along with advantages and benefits of using these materials for various components in high temperature applications.

  3. Design and Fabrication of E-Glass /carbon/graphite epoxy hybrid composite leaf spring

    Science.gov (United States)

    Gopalakrishnan, T.; Raja, M.; Jothi Prakash, V. M.; Gnanavel, C.

    2017-03-01

    The Automobile Industry has shown increase interest for replacement of steel leaf spring with that of composite leaf spring. Substituting composite materials for conventional metallic materials has many advantages because of higher specific stiffness, strength and fatigue resistance etc. This work deals with the replacement of conventional steel leaf spring with a hybrid Composite leaf spring using E -Glass/Carbon/Graphite/Epoxy. The hybrid composite is obtained by introducing more than one fiber in the reinforcement phase. The hybrid composite is fabricated by the vacuum bag technique. The result shows that introduction of carbon and graphite fiber in the reinforcement phase increases the stiffness of the composite.

  4. MoSi2-Base Hybrid Composite Passed Engine Test

    Science.gov (United States)

    Keith, Theo G., Jr.; Hebsur, Mohan

    1998-01-01

    The intermetallics compound molybdenum disilicide (MoSi2) is an attractive high-temperature structural material for advanced engine applications. It has excellent oxidation resistance, a high melting point, relatively low density, and high thermal conductivity, and it is easily machined. Past research'at the NASA Lewis Research Center has resulted in the development of a hybrid composite consisting of a MoSi2 matrix reinforced with silicon nitride (Si3N4) Particulate and silicon carbide (SiC) fibers. This composite has demonstrated attractive strength, toughness, thermal fatigue, and oxidation resistance, including resistance to "pest" oxidation. These properties attracted the interest of the Office of Naval Research and Pratt & Whitney, and a joint NASA/Navy/Pratt & Whitney effort was developed to continue to mature the MoSi2 Composite technology. A turbine blade outer air seal, which was part of the Integrated High Performance Turbine Engine Technology (IHPTET) program, was chosen as a first component on which to focus. The first tasks of the materials development effort were to develop improved processing methods to reduce costs and to use fine-diameter fibers that enable the manufacturing of complex shapes. Tape-casting methods were developed to fully infiltrate the fine SiC fibers with matrix powders. The resulting composites were hot pressed to 100-percent density. Composites with cross-plied fiber architectures with 30 vol. % hi-nicalon SiC fibers and 30 vol. % nitride particles are now made routinely and demonstrate a good balance of properties. The next task entailed the measurement of a wide variety of mechanical properties to confirm the suitability of this composite in engines. In particular, participants in this effort demonstrated that composites made with Hi-Nicalon fibers had strength and toughness properties equal to or better than those of the composites made with the large-diameter fibers that had been used previously. Another critically

  5. Influence of Carbon & Glass Fiber Reinforcements on Flexural Strength of Epoxy Matrix Polymer Hybrid Composites

    Directory of Open Access Journals (Sweden)

    T.D. Jagannatha

    2015-04-01

    Full Text Available Hybrid composite materials are more attracted by the engineers because of their properties like stiffness and high specific strength which leads to the potential application in the area of aerospace, marine and automobile sectors. In the present investigation, the flexural strength and flexural modulus of carbon and glass fibers reinforced epoxy hybrid composites were studied. The vacuum bagging technique was adopted for the fabrication of polymer hybrid composite materials. The hardness, flexural strength and flexural modulus of the hybrid composites were determined as per ASTM standards. The hardness, flexural strength and flexural modulus were improved as the fiber reinforcement contents increased in the epoxy matrix material.

  6. SERS of semiconducting nanoparticles (TIO{sub 2} hybrid composites).

    Energy Technology Data Exchange (ETDEWEB)

    Rajh, T.; Musumeci, A.; Gosztola, D.; Schiller, T.; Dimitrijevic, N. M.; Mujica, V.; Martin, D.; Center for Nanoscale Materials

    2009-05-06

    Raman scattering of molecules adsorbed on the surface of TiO{sub 2} nanoparticles was investigated. We find strong enhancement of Raman scattering in hybrid composites that exhibit charge transfer absorption with TiO{sub 2} nanoparticles. An enhancement factor up to {approx}10{sup 3} was observed in the solutions containing TiO{sub 2} nanoparticles and biomolecules, including the important class of neurotransmitters such as dopamine and dopac (3,4-dihydroxy-phenylacetic acid). Only selected vibrations are enhanced, indicating molecular specificity due to distinct binding and orientation of the biomolecules coupled to the TiO{sub 2} surface. All enhanced modes are associated with the asymmetric vibrations of attached molecules that lower the symmetry of the charge transfer complex. The intensity and the energy of selected vibrations are dependent on the size and shape of nanoparticle support. Moreover, we show that localization of the charge in quantized nanoparticles (2 nm), demonstrated as the blue shift of particle absorption, diminishes SERS enhancement. Importantly, the smallest concentration of adsorbed molecules shows the largest Raman enhancements suggesting the possibility for high sensitivity of this system in the detection of biomolecules that form a charge transfer complex with metal oxide nanoparticles. The wavelength-dependent properties of a hybrid composite suggest a Raman resonant state. Adsorbed molecules that do not show a charge transfer complex show weak enhancements probably due to the dielectric cavity effect.

  7. ASSESMENT OF SELF HEALING PROPERTY IN HYBRID FIBER POLYMERIC COMPOSITE

    Directory of Open Access Journals (Sweden)

    N.ABILASH

    2011-07-01

    Full Text Available In recent years, Natural fiber reinforced composites is an emerging area in polymer technology. Fibers resulting from plants are considered a budding substitute for non-renewable synthetic fibers like glass and carbon fibers. The objective of this study is to merge the benefits of natural and synthetic fibers by developing ahybrid composite of jute and glass fibers along with self healing property to eliminate delamination without compromising the benefits of hybridization. This concept offers the designer an ability to incorporate secondary functional ability of counteracting service degradation in addition to achieving the primary, usually structuralintegrity, requirement. The self-healing approach utilizes a releasable healing agent contained in a hollow fiber that is embedded in a resin system. Specimens are produced using a hollow glass fiber and epoxy resin. In addition, in the case of multiple fibers test, e-glass fibers are incorporated in the composite. When a crack isinitiated and propagates through the composite breaking the hollow fiber, a liquid healing agent comes out and fills the crack gap. Polymerization of the monomer healing agent is facilitated when it contacts a catalyst that is pre-coated on the outside surface of the hollow glass fiber. Self-healing materials also have the benefit ofoffering lighter and optimized structures as well as reduced maintenance cost.

  8. Impedance characterization of epoxy composite containing conductive hybrid carbon fillers

    Science.gov (United States)

    Othman, Raja Nor; Tawil, Siti Nooraya; Zailan, Suhaila

    2017-08-01

    Epoxy composites containg carbon fillers are prepared in this work with an intention to characterise their electrical properties. The performance of electrical conductivity of epoxy composites is assessed by adding various loadings of conductive carbon fillers into the neat epoxy. First, Carbon Black (CB) was incorporated within epoxy matrix at several loadings. The increase in the specific conductivity of more than five orders of magnitude was observed between 3 wt. % and 4 wt.% CB loading, recorded at 10 kHz frequency. As such, the critical percolation loading, pc was recorded in between 3 wt.% and 4 wt.%. For the samples containing CB at loading 4 wt.% and above, the conductivity remains independent of the frequency, indicating a purely ohmic behaviour. It is also observed that the specific conductivity values can be altered by increasing the hardener stirring time up to 15 minutes, where the pc was successfully lowered down to < 3 wt. % It was further intended to study the hybrid effects by adding CNT to the composites. The conductivity data showed that the composite becomes frequency independent, even at 2 wt. % carbon loading (1 wt. % CB + 1 wt. % CNT), demonstrating the roles contributed by high aspect ratio conductive CNT in enhancing the formation of percolated path at much lower loading.

  9. Hybrid S2/Carbon Epoxy Composite Armours Under Blast Loads

    Science.gov (United States)

    Dolce, F.; Meo, Michele; Wright, A.; French, M.; Bernabei, M.

    2012-06-01

    Civil and military structures, such as helicopters, aircrafts, naval ships, tanks or buildings are susceptible to blast loads as terroristic attacks increases, therefore there is the need to design blast resistant structures. During an explosion the peak pressure produced by shock wave is much greater than the static collapse pressure. Metallic structures usually undergo large plastic deformations absorbing blast energy before reaching equilibrium. Due to their high specific properties, fibre-reinforced polymers are being considered for energy absorption applications in blast resistant armours. A deep insight into the relationship between explosion loads, composite architecture and deformation/fracture behaviour will offer the possibility to design structures with significantly enhanced energy absorption and blast resistance performance. This study presents the results of a numerical investigation aimed at understanding the performance of a hybrid composite (glass/carbon fibre) plate subjected to blast loads using commercial LS-DYNA software. In particular, the paper deals with numerical 3D simulations of damages caused by air blast waves generated by C4 charges on two fully clamped rectangular plates made of steel and hybrid (S2/Carbon) composite, respectively. A Multi Materials Arbitrary Lagrangian Eulerian (MMALE) formulation was used to simulate the shock phenomenon. For the steel plates, the Johnson-Cook material model was employed. For the composite plates both in-plane and out-of-plane failure criteria were employed. In particular, a contact tiebreak formulation with a mixed mode failure criteria was employed to simulate delamination failure. As for the steel plates the results showed that excellent correlation with the experimental data for the two blast load conditions in terms of dynamic and residual deflection for two different C4 charges. For the composite plates the numerical results showed that, as expected, a wider delamination damage was observed

  10. Spot Welding of Honeycomb Structures

    Science.gov (United States)

    Cohal, V.

    2017-08-01

    Honeycomb structures are used to prepare meals water jet cutting machines for textile. These honeycomb structures are made of stainless steel sheet thickness of 0.1-0.2 mm. Corrugated sheet metal strips are between two gears with special tooth profile. Hexagonal cells for obtaining these strips are welded points between them. Spot welding device is three electrodes in the upper part, which carries three welding points across the width of the strip of corrugated sheet metal. Spot welding device filled with press and advance mechanisms. The paper presents the values of the regime for spot welding.

  11. Unconventional superconductivity in honeycomb lattice

    Directory of Open Access Journals (Sweden)

    P Sahebsara

    2013-03-01

    Full Text Available   ‎ The possibility of symmetrical s-wave superconductivity in the honeycomb lattice is studied within a strongly correlated regime, using the Hubbard model. The superconducting order parameter is defined by introducing the Green function, which is obtained by calculating the density of the electrons ‎ . In this study showed that the superconducting order parameter appears in doping interval between 0 and 0.5, and x=0.25 is the optimum doping for the s-wave superconductivity in honeycomb lattice.

  12. Experimental and theoretical assessment of flexural properties of hybrid natural fibre composites

    DEFF Research Database (Denmark)

    Raghavalu Thirumalai, Durai Prabhakaran; Toftegaard, Helmuth Langmaack; Markussen, Christen Malte

    2014-01-01

    The concept of hybridization of natural fibre composites with synthetic fibres is attracting increasing scientific attention. The present study addresses the flexural properties of hybrid flax/glass/epoxy composites to demonstrate the potential benefits of hybridization. The study covers both...... experimental and theoretical assessments. Composite laminates with different hybrid fibre mixing ratios and different layer configurations were manufactured, and their volumetric composition and flexural properties were measured. The relationship between volume fractions in the composites is shown to be well...... predicted as a function of the hybrid fibre mixing ratio. The flexural modulus of the composites is theoretically assessed by using micromechanical models and laminate theory. The model predictions are compared with the experimentally determined flexural properties. Both approaches show that the flexural...

  13. Mechanical and tribological studies on nano particles reinforced hybrid aluminum based composite

    Directory of Open Access Journals (Sweden)

    Muley Aniruddha V.

    2015-01-01

    Full Text Available Hybrid metal matrix composites are new class of materials due to their better mechanical properties which can be achieved through proper selection and combination of materials. The work reported in this paper is based on fabrication of hybrid composites by using nano particles as reinforcements. The hybrid composites were fabricated by reinforcing them with nano sized SiC and Al2O3 particles in order to study mechanical and tribological properties of these enhanced materials. A stir casting method was used to obtain hybrid composites. LM 6 aluminum alloy was used as a matrix material. The results shown increase in hardness as well as in ultimate tensile strength of the composites with small wt.% of nano-sized hybrid reinforcements. The composites produced also exhibit better tribological properties.

  14. Hybrid carbon/glass fiber composites: Micromechanical analysis of structure–damage resistance relationships

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon; Dai, Gaoming

    2014-01-01

    A computational study of the effect of microstructure of hybrid carbon/glass fiber composites on their strength is presented. Unit cells with hundreds of randomly located and misaligned fibers of various properties and arrangements are subject to tensile and compression loading, and the evolution...... of fiber damages is analyzed in numerical experiments. The effects of fiber clustering, matrix properties, nanoreinforcement, load sharing rules on the strength and damage resistance of composites are studied. It was observed that hybrid composites under uniform displacement loading might have lower...... strength than pure composites, while the strength of hybrid composites under inform force loading increases steadily with increasing the volume content of carbon fibers....

  15. Fiber-reinforced bioactive and bioabsorbable hybrid composites

    Energy Technology Data Exchange (ETDEWEB)

    Huttunen, Mikko; Godinho, Pedro; Kellomaeki, Minna [Tampere University of Technology, Institute of Biomaterials, Hermiankatu 12, PO Box 589, FIN-33101 Tampere (Finland); Toermaelae, Pertti [Bioretec Ltd, Hermiankatu 22, PO Box 135, FI-33721 Tampere (Finland)], E-mail: mikko.huttunen@tut.fi

    2008-09-01

    Bioabsorbable polymeric bone fracture fixation devices have been developed and used clinically in recent decades to replace metallic implants. An advantage of bioabsorbable polymeric devices is that these materials degrade in the body and the degradation products exit via metabolic routes. Additionally, the strength properties of the bioabsorbable polymeric devices decrease as the device degrades, which promotes bone regeneration (according to Wolff's law) as the remodeling bone tissue is progressively loaded. The most extensively studied bioabsorbable polymers are poly-{alpha}-hydroxy acids. The major limitation of the first generation of bioabsorbable materials and devices was their relatively low mechanical properties and brittle behavior. Therefore, several reinforcing techniques have been used to improve the mechanical properties. These include polymer chain orientation techniques and the use of fiber reinforcements. The latest innovation for bioactive and fiber-reinforced bioabsorbable composites is to use both bioactive and bioresorbable ceramic and bioabsorbable polymeric fiber reinforcement in the same composite structure. This solution of using bioactive and fiber-reinforced bioabsorbable hybrid composites is examined in this study.

  16. Ultra-high modulus organic fiber hybrid composites

    Science.gov (United States)

    Champion, A. R.

    1981-01-01

    An experimental organic fiber, designated Fiber D, was characterized, and its performance as a reinforcement for composites was investigated. The fiber has a modulus of 172 GPa, tensile strength of 3.14 GPa, and density of 1.46 gm/cu cm. Unidirectional Fiber D/epoxy laminates containing 60 percent fiber by volume were evaluated in flexure, shear, and compression, at room temperature and 121 C in both the as fabricated condition and after humidity aging for 14 days at 95 percent RH and 82 C. A modulus of 94.1 GPa, flexure strength of 700 MPa, shear strength of 54 MPa, and compressive strength of 232 MPa were observed at room temperature. The as-fabricated composites at elevated temperature and humidity aged material at room temperature had properties 1 to 20 percent below these values. Combined humidity aging plus evaluated temperature testing resulted in even lower mechanical properties. Hybrid composite laminates of Fiber D with Fiber FP alumina or Thornel 300 graphite fiber were also evaluated and significant increases in modulus, flexure, and compressive strengths were observed.

  17. Influence of Stacking Sequence and Notch Angle on the Charpy Impact Behavior of Hybrid Composites

    Science.gov (United States)

    Behnia, S.; Daghigh, V.; Nikbin, K.; Fereidoon, A.; Ghorbani, J.

    2016-09-01

    The low-velocity impact behavior of hybrid composite laminates was investigated. The epoxy matrix was reinforced with aramid, glass, basalt, and carbon fabrics using the hand lay-up technique. Different stacking sequences and notch angles were and notch angles considered and tested using a Charpy impact testing machine to study the hybridization and notch angle effects on the impact response of the hybrid composites. The energy absorption capability of specimens with different stacking sequences and notch angles is compared and discussed. It is shown that the hybridization can enhance the mechanical performance of composite materials.

  18. Fatigue Life Analysis of Tapered Hybrid Composite Flexbeams

    Science.gov (United States)

    Murri, Gretchen B.; Schaff, Jeffery R.; Dobyns, Alan L.

    2002-01-01

    Nonlinear-tapered flexbeam laminates from a full-size composite helicopter rotor hub flexbeam were tested under combined constant axial tension and cyclic bending loads. The two different graphite/glass hybrid configurations tested under cyclic loading failed by delamination in the tapered region. A 2-D finite element model was developed which closely approximated the flexbeam geometry, boundary conditions, and loading. The analysis results from two geometrically nonlinear finite element codes, ANSYS and ABAQUS, are presented and compared. Strain energy release rates (G) obtained from the above codes using the virtual crack closure technique (VCCT) at a resin crack location in the flexbeams are presented for both hybrid material types. These results compare well with each other and suggest that the initial delamination growth from the resin crack toward the thick region of the flexbeam is strongly mode II. The peak calculated G values were used with material characterization data to calculate fatigue life curves and compared with test data. A curve relating maximum surface strain to number of loading cycles at delamination onset compared reasonably well with the test results.

  19. Characterisation of metal–thermoplastic composite hybrid joints by means of a mandrel peel test

    NARCIS (Netherlands)

    Su, Yibo; Rooij, de Matthijn; Grouve, Wouter; Warnet, Laurent

    2016-01-01

    Fastener free metal–carbon fibre reinforced thermoplastic composite hybrid joints show potential for application in aerospace structures. The strength of the metal–thermoplastic composite interface is crucial for the performance of the entire hybrid joint. Optimisation of the interface requires an e

  20. Study of Cylindrical Honeycomb Solar Collector

    Directory of Open Access Journals (Sweden)

    Atish Mozumder

    2014-01-01

    Full Text Available We present the results of our investigation on cylindrical honeycomb solar collector. The honeycomb has been fabricated with transparent cellulose triacetate polymer sheets. Insulation characteristics of the honeycomb were studied by varying the separation between the honeycomb and the absorber plate. The optimal value of the separation was found to be 3.3 mm for which the heat transfer coefficient is 3.06 W m−2 K−1. This supports result of previous similar experiments. Further we test the honeycomb through a field experiment conducted in Delhi (28.6°N, 77°E and found that when the incident angle of the solar radiation is within 20° then the performance of the system with the honeycomb is better than the one without the honeycomb.

  1. Nonlinear acoustics and honeycomb materials

    Science.gov (United States)

    Thompson, D. O.

    2012-05-01

    The scope of research activity that Bruce Thompson embraced was very large. In this talk three different research topics that the author shared with Bruce are reviewed. They represent Bruce's introduction to NDE and include nonlinear acoustics, nondestructive measurements of adhesive bond strengths in honeycomb panels, and studies of flexural wave dispersion in honeycomb materials. In the first of these, four harmonics of a 30 Mhz finite amplitude wave were measured for both fused silica and aluminum single crystals with varying lengths and amounts of cold work using a capacity microphone with heterodyne receiver with a flat frequency response from 30 to 250 Mhz. The results for fused silica with no dislocation structure could be described by a model due to Fubini, originally developed for gases, that depends upon only the second and third order elastic constants and not the fourth and higher order constants. The same was not true for the aluminum with dislocation structures. These results raised some questions about models for harmonic generation in materials with dislocations. In the second topic, experiments were made to determine the adhesive bond strengths of honeycomb panels using the vibrational response of the panels (Chladni figures). The results showed that both the damping characteristics of panel vibrations as a whole and velocity of propagation of elastic waves that travel along the surface and sample the bondline can be correlated with destructively determined bond strengths. Finally, the phase velocity of flexural waves traveling along a 1-inch honeycomb sandwich panel was determined from 170 Hz to 50 Khz, ranging from 2.2×104 cm/sec at the low end to 1.18×105 cm/sec at 40 Khz. The dispersion arises from the finite thickness of the panel and agreed with the results of continuum models for the honeycomb. Above 40 Khz, this was not the case. The paper concludes with a tribute to Bruce for his many wonderful contributions and lessons beyond his

  2. 基于匹配追踪的蜂窝夹层复合材料损伤检测%Research on honeycomb sandwich composite structure damage detection based on matching pursuit method

    Institute of Scientific and Technical Information of China (English)

    冯勇明; 周丽; 李真

    2012-01-01

    基于Lamb波和匹配追踪时频分析方法,提出一种损伤成像方法,对蜂窝夹层复合材料结构进行损伤监测.首先针对Lamb波传播的特点,提出了匹配追踪方法的快速实现方案,该方法能准确地匹配失真变形的窄带脉冲信号,并识别Lamb波的模态;然后对由压电传感器采集到的Lamb波信号,采用匹配追踪方法提取特征信息,得到Lamb波的能量分布;在此基础上,考虑Lamb波在各向异性结构中传播速度的影响,将损伤处的散射波能量分布和各像素点对比度联系起来,得到损伤图像,将损伤的情况可视化.通过蜂窝夹层复合材料结构实验验证了该方法的可行性和有效性.%This study proposes a damage imaging method using Lamb wave and matching pursuit method time-frequency analysis for damage detection of honeycomb sandwich structure. Matching pursuit method is employed to decompose Lamb wave signals into a linear expansion of several chirplet atoms using a fast realization algorithm. The relationship between Lamb wave' s dispersion and the chirplet' s chirp rate is established, which can be used to identify the modes of Lamb waves. Then the matching pursuit method is applied to the Lamb wave signals excited and sensed by piezoelectric sensors in the time-frequency domain, which can obtain the energy distribution of the scattered waves. Considering the effect of anisotropic property on the velocity distributions of Lamb waves, the damage image can be obtained by the time-dependent energy distribution of scattered waves. The effectiveness and accuracy of the proposed method in identifying the modes and in locating defects are demonstrated by the experimental results on the honeycomb sandwich composite structure.

  3. Fracture Toughness Evaluation of Hybrid and Nano-hybrid Resin Composites after Ageing under Acidic Environment

    Directory of Open Access Journals (Sweden)

    Ferooz M

    2015-03-01

    Full Text Available Statement of Problem: Tooth-coloured restorative materials are brittle with the major shortcomings of sensitivity to flaws and defects. Although various mechanical properties of resin composites have been studied, no fracture toughness test data for nano-hybrid composites under acidic condition for a long period of time has been published. Objectives: To compare the fracture toughness (KIc of two types of resin composites under tensile loading and to assess the effect of distilled water and lactic acid on the resistance of the restoratives to fracture after three months of immersion. Materials and Methods: Four resin composites were used: three nanohybrids [EsteliteSigma Quick (Kuraray, Luna (SDI, Paradigm (3M/ESPE] and one hybrid, Rok (SDI. The specimens were prepared using a custom-made polytetrafluorethylene split mould, stored in distilled water (pH 6.8 or 0.01mol/L lactic acid (pH 4 and conditioned at 37°C for 24 hours, 1 or 3 months. They were loaded under tensile stress using a universal testing machine; the maximum load (N to the specimen failure was recorded and the fracture toughness (KIc was calculated. Data were analysed by ANOVA and Tukey’s test using SPSS, version 18. Results: The results of two-way ANOVA did not show a significant combined effect of material, time, and storage medium on fracture toughness (p= 0.056. However, there was a strong interaction between materials and time (p=0.001 when the storage medium were ignored. After 24 h of immersion in distilled water, Paradigm revealed the highest KIc values followed by Rok, Luna and Estelite. Immersion in either distilled water or lactic acid significantly decreased the fracture toughness of almost all materials as time interval increased. Conclusions: Paradigm showed the highest fracture toughness followed by Rok, Luna and Estelite respectively. As time increased, KIc significantly decreased for almost all resin composites except for Luna which showed a slight decrease

  4. Analysis of SMA Hybrid Composite Structures using Commercial Codes

    Science.gov (United States)

    Turner, Travis L.; Patel, Hemant D.

    2004-01-01

    A thermomechanical model for shape memory alloy (SMA) actuators and SMA hybrid composite (SMAHC) structures has been recently implemented in the commercial finite element codes MSC.Nastran and ABAQUS. The model may be easily implemented in any code that has the capability for analysis of laminated composite structures with temperature dependent material properties. The model is also relatively easy to use and requires input of only fundamental engineering properties. A brief description of the model is presented, followed by discussion of implementation and usage in the commercial codes. Results are presented from static and dynamic analysis of SMAHC beams of two types; a beam clamped at each end and a cantilevered beam. Nonlinear static (post-buckling) and random response analyses are demonstrated for the first specimen. Static deflection (shape) control is demonstrated for the cantilevered beam. Approaches for modeling SMAHC material systems with embedded SMA in ribbon and small round wire product forms are demonstrated and compared. The results from the commercial codes are compared to those from a research code as validation of the commercial implementations; excellent correlation is achieved in all cases.

  5. Three-dimensional finite element simulation of intermingled-fiber hybrid composite behavior

    Science.gov (United States)

    Mital, Subodh K.; Chamis, Christos C.

    1992-01-01

    Three-dimensional finite element methods and the intraply hybrid micromechanics equations are used to predict composite properties for a unidirectional graphite-epoxy primary composite with S-glass fibers used as hybridizing fibers. The micromechanics equations are embedded in a computer code ICAN (Integrated Composites Analyzer). The three-dimensional finite element model consists of three-by-three unit cell array, with a total fiber volume ratio of 0.54. There is a good agreement between the composite properties and microstresses obtained from both methods. The results indicate that the finite element methods and micromechanics equations can be used to obtain the properties of intermingled hybrid composites needed for analysis/design of hybrid composite structures.

  6. Nanoscopic dynamics in hybrid hydroxyapatite-CTAB composite

    Science.gov (United States)

    Dubey, P. S.; Sharma, V. K.; Mitra, S.; Verma, G.; Hassan, P. A.; Dutta, B.; Johnson, M.; Mukhopadhyay, R.

    2017-06-01

    Synthetic hydroxyapatite (HAp) is an important material in biomedical engineering due to its excellent biocompatibility and bioactivity. HAp nanoparticles were synthesized by the co-precipitation method using cetyltrimethylammonium bromide (CTAB) micelles as a template and are characterized using x-ray diffraction, electron microscopy, and thermal gravimetric measurements. Transmission electron microscope (TEM) demonstrates the formation of rod-shaped HAp. Dynamics of CTAB in HAp-CTAB composite as studied by using quasielastic neutron scattering (QENS) technique is reported here. HAp-CTAB composite provides an ideal system for studying the dynamics of CTAB micelles without any aqueous media. QENS data indicate that the observed dynamics are reminiscent of localized motions in ionic micellar systems, consisting of segmental and fast torsional motions. Segmental dynamics has been described with a model, in which hydrogen atoms in the alkyl chain undergoes localized translation diffusion and the CH3 unit associated with the head group undergo 3-fold jump rotation. Within this model, the hydrogen atoms in the alkyl chain undergo diffusion within spherical domains having different radii and diffusivities. A simple linear distribution of the radius and diffusivity has been assumed, in which the CH2 unit nearest to the head group has the least value and the ones furthest from the head group, that is, at the end of the alkyl chain has the largest value. The fast torsional motion is described by a 2-fold jump rotation model. Quantitative estimate of the different parameters characterizing various dynamical motions active within the time scale of the instrument is also presented. We have provided a detailed description of the observed dynamical features in hybrid HAp-CTAB composite, a potential candidate for biomedical applications.

  7. Hybrid polymer composite membrane for an electromagnetic (EM) valveless micropump

    Science.gov (United States)

    Said, Muzalifah Mohd; Yunas, Jumril; Bais, Badariah; Azlan Hamzah, Azrul; Yeop Majlis, Burhanuddin

    2017-07-01

    In this paper, we report on a hybrid membrane used as an actuator in an electromagnetically driven valveless micropump developed using MEMS processes. The membrane structure consists of the combination of a magnetic polymer composite membrane and an attached bulk permanent magnet which is expected to have a compact structure and a strong magnetic force with maintained membrane flexibility. A soft polymeric material made of polydimethylsiloxane (PDMS) is initially mixed with neodymium magnetic particles (NdFeB) to form a magnetic polymer composite membrane. The membrane is then bonded with the PDMS based microfluidic part, developed using soft lithography process. The developed micropump was tested in terms of the actuator membrane deflection capability and the fluidic flow of the injected fluid sample through the microfluidic channel. The experimental results show that the magnetic composite actuator membrane with an attached bulk permanent magnet is capable of producing a maximum membrane deflection of up to 106 µm. The functionality test of the electromagnetic (EM) actuator for fluid pumping purposes was done by supplying an AC voltage with various amplitudes, signal waves and frequencies. A wide range of sample injection rates from a few µl min-1 to tens of nl min-1 was achieved with a maximum flow rate of 6.6 µl min-1. The injection flow rate of the EM micropump can be controlled by adjusting the voltage amplitude and frequency supplied to the EM coil, to control the membrane deflection in the pump chamber. The designed valveless EM micropump has a very high potential to enhance the drug delivery system capability in biomedical applications.

  8. Mechanical properties of additively manufactured octagonal honeycombs.

    Science.gov (United States)

    Hedayati, R; Sadighi, M; Mohammadi-Aghdam, M; Zadpoor, A A

    2016-12-01

    Honeycomb structures have found numerous applications as structural and biomedical materials due to their favourable properties such as low weight, high stiffness, and porosity. Application of additive manufacturing and 3D printing techniques allows for manufacturing of honeycombs with arbitrary shape and wall thickness, opening the way for optimizing the mechanical and physical properties for specific applications. In this study, the mechanical properties of honeycomb structures with a new geometry, called octagonal honeycomb, were investigated using analytical, numerical, and experimental approaches. An additive manufacturing technique, namely fused deposition modelling, was used to fabricate the honeycomb from polylactic acid (PLA). The honeycombs structures were then mechanically tested under compression and the mechanical properties of the structures were determined. In addition, the Euler-Bernoulli and Timoshenko beam theories were used for deriving analytical relationships for elastic modulus, yield stress, Poisson's ratio, and buckling stress of this new design of honeycomb structures. Finite element models were also created to analyse the mechanical behaviour of the honeycombs computationally. The analytical solutions obtained using Timoshenko beam theory were close to computational results in terms of elastic modulus, Poisson's ratio and yield stress, especially for relative densities smaller than 25%. The analytical solutions based on the Timoshenko analytical solution and the computational results were in good agreement with experimental observations. Finally, the elastic properties of the proposed honeycomb structure were compared to those of other honeycomb structures such as square, triangular, hexagonal, mixed, diamond, and Kagome. The octagonal honeycomb showed yield stress and elastic modulus values very close to those of regular hexagonal honeycombs and lower than the other considered honeycombs.

  9. Effect of accelerated environmental aging on tensile properties of oil palm/jute hybrid composites

    Science.gov (United States)

    Jawaid, M.; Saba, N.; Alothman, O.; Paridah, M. T.

    2016-11-01

    Recently natural fibre based hybrid composites are receiving growing consideration due to environmental and biodegradability properties. In order to look behaviour of hybrid composites in outdoor applications, its environmental degradation properties such as UV accelerated weathering properties need to analyze. In this study oil palm empty fruit bunch (EFB) and jute fibres reinforced hybrid composites, pure EFB, pure jute and epoxy composites were fabricated through hand lay-up techniques. Hybrid composites with different layering pattern (EFB/jute/EFB and Jute/EFB/jute) while maintaining 40 wt. % total fibre loading were fabricates to compared with EFB and jute composites. Effect of UV accelerated environmental aging on tensile properties of epoxy, pure EFB, pure jute, and hybrid composites were assessed and evaluate under UV exposure. Tensile samples of all composites were subjected to accelerated weathering for 100h, at temperature (75°C), relative humidity (35%), Light (125 W/m2), and water spray off. Obtained results indicated that there is reduction in tensile strength, modulus and elongation at break values of hybrid and pure composites due to degradation of lignin and fibre-matrix interfacial bonding.

  10. Demonstration of Minimally Machined Honeycomb Silicon Carbide Mirrors

    Science.gov (United States)

    Goodman, William

    2012-01-01

    Honeycomb silicon carbide composite mirrors are made from a carbon fiber preform that is molded into a honeycomb shape using a rigid mold. The carbon fiber honeycomb is densified by using polymer infiltration pyrolysis, or through a reaction with liquid silicon. A chemical vapor deposit, or chemical vapor composite (CVC), process is used to deposit a polishable silicon or silicon carbide cladding on the honeycomb structure. Alternatively, the cladding may be replaced by a freestanding, replicated CVC SiC facesheet that is bonded to the honeycomb. The resulting carbon fiber-reinforced silicon carbide honeycomb structure is a ceramic matrix composite material with high stiffness and mechanical strength, high thermal conductivity, and low CTE (coefficient of thermal expansion). This innovation enables rapid, inexpensive manufacturing. The web thickness of the new material is less than 1 millimeter, and core geometries tailored. These parameters are based on precursor carbon-carbon honeycomb material made and patented by Ultracor. It is estimated at the time of this reporting that the HoneySiC(Trademark) will have a net production cost on the order of $38,000 per square meter. This includes an Ultracor raw material cost of about $97,000 per square meter, and a Trex silicon carbide deposition cost of $27,000 per square meter. Even at double this price, HoneySiC would beat NASA's goal of $100,000 per square meter. Cost savings are estimated to be 40 to 100 times that of current mirror technologies. The organic, rich prepreg material has a density of 56 kilograms per cubic meter. A charred carbon-carbon panel (volatile organics burnt off) has a density of 270 kilograms per cubic meter. Therefore, it is estimated that a HoneySiC panel would have a density of no more than 900 kilograms per cubic meter, which is about half that of beryllium and about onethird the density of bulk silicon carbide. It is also estimated that larger mirrors could be produced in a matter of weeks

  11. Fracture resistance of teeth restored with packable and hybrid composites

    Directory of Open Access Journals (Sweden)

    Ghavam M

    2006-06-01

    Full Text Available Background and Aim: With recent introduction of packable composites, it is claimed that they apply less stress on tooth structure because of reduced polymerization shrinkage, and similarity of coefficient of thermal expansion to tooth structure. However, the high viscosity may in turn cause less adaptation, so it is not clearly known whether these materials strengthen tooth structure or not. The aim of this study was to evaluate fracture resistance of maxillary premolars, receiving hybrid or packable composite restorations with different methods of application and curing. Materials and Methods: In this experimental study, seventy five intact premolars were randomly assigned to five groups of 15 teeth each. One group was maintained intact as the control group. Similar MOD cavities were prepared in the other teeth. The teeth in group two were restored with Spectrum in incremental layers and light cured with 500 mw/cm2 intensity. The third group were filled with Surefil and cured with light intensity of 500 mw/cm2. The groups four and five were restored with Surefil in bulk technique with two different modes: 500 mw/cm2 intensity and a ramp mode (100-900 mw/cm2 respectively. After thermocycling, force to fracture was assessed and degree of conversion (DC at the bottom of cavities was evaluated for different modes and methods. The curing and placement methods in groups tested for DC (A to D were the same as fracture resistance groups (2 to 5. Data were analyzed using one way ANOVA and Tukey HSD tests with p<0.05 as the limit of significance. Results: All the restored groups showed significantly less fracture resistance than the control group, but had no significant difference among themselves. DC of Spectrum was higher than Surefil. Bulk method with 500 mw/cm2 light intensity, significantly decreased DC. DC in bulk method with high light intensity was not significantly different from incremental method with 500 mw/cm2 light intensity. Conclusion

  12. Mode I fracture toughness of carbon-glass/epoxy interply hybrid composites

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Ha Na; Kim, Yon Jig [Chonbuk National University, Jeonju (Korea, Republic of)

    2015-05-15

    In this study, the fracture toughness of carbon-glass fiber reinforced epoxy interply hybrid composite was investigated. In this experiment, the interply hybrid composites were manufactured using a vacuum-assisted resin transfer molding (VARTM) process. The fracture toughness of the interply hybrid composites was decreased with increasing the number of glass fabrics. The decrease in fracture toughness with an increase in the glass fiber content can be expressed in the form of a linear equation. Test results showed that the arrangement of fiber significantly influences the fracture toughness of the composite material. Glass fiber was effective against improving the fracture toughness of the hybrid composite when the glass fibers are dispersed by multi layers rather than a single layer.

  13. Hybrid Fibre Polylactide Acid Composite with Empty Fruit Bunch: Chopped Glass Strands

    Directory of Open Access Journals (Sweden)

    K. Y. Tshai

    2014-01-01

    Full Text Available Hybrid polylactide acid (PLA composites reinforced with palm empty fruit bunch (EFB and chopped strand E-glass (GLS fibres were investigated. The hybrid fibres PLA composite was prepared through solution casting followed by pelletisation and subsequent hot compression press into 1 mm thick specimen. Chloroform and dichloromethane were used as solvent and their effectiveness in dissolving PLA was reported. The overall fibre loading was kept constant at volume fraction, Vf, of 20% while the ratio of EFB to GLS fibre was varied between Vf of 0 : 20 to 20 : 0. The inclusion of GLS fibres improved the tensile and flexural performance of the hybrid composites, but increasing the glass fibre length from 3 to 6 mm has a negative effect on the mechanical properties of the hybrid composites. Moreover, the composites that were prepared using chloroform showed superior tensile and flexural properties compared to those prepared with dichloromethane.

  14. Hybrid and hierarchical nanoreinforced polymer composites: Computational modelling of structure–properties relationships

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon; Dai, Gaoming

    2014-01-01

    Hybrid and hierarchical polymer composites represent a promising group of materials for engineering applications. In this paper, computational studies of the strength and damage resistance of hybrid and hierarchical composites are reviewed. The reserves of the composite improvement are explored...... by using computational micromechanical models. It is shown that while glass/carbon fibers hybrid composites clearly demonstrate higher stiffness and lower weight with increasing the carbon content, they can have lower strength as compared with usual glass fiber polymer composites. Secondary...... nanoreinforcement can drastically increase the fatigue lifetime of composites. Especially, composites with the nanoplatelets localized in the fiber/matrix interface layer (fiber sizing) ensure much higher fatigue lifetime than those with the nanoplatelets in the matrix....

  15. Fatigue Life Methodology for Tapered Hybrid Composite Flexbeams

    Science.gov (United States)

    urri, Gretchen B.; Schaff, Jeffery R.

    2006-01-01

    Nonlinear-tapered flexbeam specimens from a full-size composite helicopter rotor hub flexbeam were tested under combined constant axial tension and cyclic bending loads. Two different graphite/glass hybrid configurations tested under cyclic loading failed by delamination in the tapered region. A 2-D finite element model was developed which closely approximated the flexbeam geometry, boundary conditions, and loading. The analysis results from two geometrically nonlinear finite element codes, ANSYS and ABAQUS, are presented and compared. Strain energy release rates (G) associated with simulated delamination growth in the flexbeams are presented from both codes. These results compare well with each other and suggest that the initial delamination growth from the tip of the ply-drop toward the thick region of the flexbeam is strongly mode II. The peak calculated G values were used with material characterization data to calculate fatigue life curves for comparison with test data. A curve relating maximum surface strain to number of loading cycles at delamination onset compared well with the test results.

  16. Preparation of zeolite-A/chitosan hybrid composites and their bioactivities and antimicrobial activities

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Liang; Gong, Jie [State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009 (China); Zeng, Changfeng [College of Mechanic and Power Engineering, Nanjing University of Technology, Nanjing 210009 (China); Zhang, Lixiong, E-mail: lixiongzhang@yahoo.com [State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009 (China)

    2013-10-15

    Zeolite-A/chitosan hybrid composites with zeolite contents of 20–55 wt.% were prepared by in situ transformation of silica/chitosan mixtures in a sodium aluminate alkaline solution through impregnation–gelation–hydrothermal synthesis. The products were characterized by X-ray diffraction, diffuse reflectance infrared Fourier transform spectroscopy, scanning electron microscopy, thermogravimetric analysis, and mercury penetration porosimetry. Their in vitro bioactivities were examined using as-synthesized and Ca{sup 2+}-exchanged hybrid composites in simulated body fluid (SBF) for hydroxyapatite (HAP) growth. Their antimicrobial activities for Escherichia coli (E. coli) in trypticase soy broth (TSB) were evaluated using Ag{sup +}-exchanged hybrid composites. The zeolite-A/chitosan hybrid composites could be prepared as various shapes, including cylinders, plates and thin films. They possessed macropores with pore sizes ranging from 100 to 300 μm and showed compressive mechanical strength as high as 3.2 MPa when the zeolite content was 35 wt.%. Fast growth on the Ca{sup 2+}-exchanged hybrid composites was observed with the highest weight gain of 51.4% in 30 days. The 35 wt.% Ag{sup +}-exchanged hybrid composite showed the highest antimicrobial activity, which could reduce the 9 × 10{sup 6} CFU mL{sup −1}E. coli concentration to zero within 4 h of incubation time with the Ag{sup +}-exchanged hybrid composite amount of 0.4 g L{sup −1}. The bioactivity and antimicrobial activity could be combined by ion-exchanging the composites first with Ca{sup 2+} and then with Ag{sup +}. These zeolite-A/chitosan hybrid composites have potential applications on tissue engineering and antimicrobial food packaging. - Graphical abstract: Zeolite A/chitosan hybrid composites were prepared by in situ transformation of precursors in the chitosan matrix, which possess macroporous structures and exhibit superior bioactivity and antimicrobial activity and potential biomedical

  17. Hybrid Testing of Composite Structures with Single-Axis Control

    DEFF Research Database (Denmark)

    Waldbjørn, Jacob Paamand; Høgh, Jacob Herold; Stang, Henrik

    2013-01-01

    a hybrid testing platform is introduced for single-component hybrid testing. In this case, the boundary between the numerical model and experimental setup is defined by multiple Degrees-Of-Freedoms (DOFs) which highly complicate the transferring of response between the two substructures. Digital Image......Hybrid testing is a substructuring technique where a structure is emulated by modelling a part of it in a numerical model while testing the remainder experimentally. Previous research in hybrid testing has been performed on multi-component structures e.g. damping fixtures, however in this paper...... Correlation (DIC) is therefore implemented for displacement control of the experimental setup. The hybrid testing setup was verified on a multicomponent structure consisting of a beam loaded in three point bending and a numerical structure of a frame. Furthermore, the stability of the hybrid testing loop...

  18. Carbon nanotube reinforced hybrid composites: Computational modeling of environmental fatigue and usability for wind blades

    DEFF Research Database (Denmark)

    Dai, Gaoming; Mishnaevsky, Leon

    2015-01-01

    The potential of advanced carbon/glass hybrid reinforced composites with secondary carbon nanotube reinforcement for wind energy applications is investigated here with the use of computational experiments. Fatigue behavior of hybrid as well as glass and carbon fiber reinforced composites...... with the secondary CNT reinforcements (especially, aligned tubes) present superior fatigue performances than those without reinforcements, also under combined environmental and cyclic mechanical loading. This effect is stronger for carbon composites, than for hybrid and glass composites....... automatically using the Python based code. 3D computational studies of environment and fatigue analyses of multiscale composites with secondary nano-scale reinforcement in different material phases and different CNTs arrangements are carried out systematically in this paper. It was demonstrated that composites...

  19. Mechanical Properties of Graphene Nanoplatelet/Carbon Fiber/Epoxy Hybrid Composites: Multiscale Modeling and Experiments

    Science.gov (United States)

    Hadden, C. M.; Klimek-McDonald, D. R.; Pineda, E. J.; King, J. A.; Reichanadter, A. M.; Miskioglu, I.; Gowtham, S.; Odegard, G. M.

    2015-01-01

    Because of the relatively high specific mechanical properties of carbon fiber/epoxy composite materials, they are often used as structural components in aerospace applications. Graphene nanoplatelets (GNPs) can be added to the epoxy matrix to improve the overall mechanical properties of the composite. The resulting GNP/carbon fiber/epoxy hybrid composites have been studied using multiscale modeling to determine the influence of GNP volume fraction, epoxy crosslink density, and GNP dispersion on the mechanical performance. The hierarchical multiscale modeling approach developed herein includes Molecular Dynamics (MD) and micromechanical modeling, and it is validated with experimental testing of the same hybrid composite material system. The results indicate that the multiscale modeling approach is accurate and provides physical insight into the composite mechanical behavior. Also, the results quantify the substantial impact of GNP volume fraction and dispersion on the transverse mechanical properties of the hybrid composite, while the effect on the axial properties is shown to be insignificant.

  20. Mechanical Properties of Graphene Nanoplatelet Carbon Fiber Epoxy Hybrid Composites: Multiscale Modeling and Experiments

    Science.gov (United States)

    Hadden, Cameron M.; Klimek-McDonald, Danielle R.; Pineda, Evan J.; King, Julie A.; Reichanadter, Alex M.; Miskioglu, Ibrahim; Gowtham, S.; Odegard, Gregory M.

    2015-01-01

    Because of the relatively high specific mechanical properties of carbon fiber/epoxy composite materials, they are often used as structural components in aerospace applications. Graphene nanoplatelets (GNPs) can be added to the epoxy matrix to improve the overall mechanical properties of the composite. The resulting GNP/carbon fiber/epoxy hybrid composites have been studied using multiscale modeling to determine the influence of GNP volume fraction, epoxy crosslink density, and GNP dispersion on the mechanical performance. The hierarchical multiscale modeling approach developed herein includes Molecular Dynamics (MD) and micromechanical modeling, and it is validated with experimental testing of the same hybrid composite material system. The results indicate that the multiscale modeling approach is accurate and provides physical insight into the composite mechanical behavior. Also, the results quantify the substantial impact of GNP volume fraction and dispersion on the transverse mechanical properties of the hybrid composite, while the effect on the axial properties is shown to be insignificant.

  1. Mechanical behavior of glass fiber polyester hybrid composite filled with natural fillers

    Science.gov (United States)

    Gupta, G.; Gupta, A.; Dhanola, A.; Raturi, A.

    2016-09-01

    Now-a-days, the natural fibers and fillers from renewable natural resources offer the potential to act as a reinforcing material for polymer composite material alternative to the use of synthetic fiber like as; glass, carbon and other man-made fibers. Among various natural fibers and fillers like banana, wheat straw, rice husk, wood powder, sisal, jute, hemp etc. are the most widely used natural fibers and fillers due to its advantages like easy availability, low density, low production cost and reasonable physical and mechanical properties This research work presents the effect of natural fillers loading with 5%, 10% and 15% on mechanical behavior of polyester based hybrid composites. The result of test depicted that hybrid composite has far better properties than single fibre glass reinforced composite under impact and flexural loads. However it is found that the hybrid composite have better strength as compared to single glass fibre composites.

  2. Compressive failure modes and parameter optimization of the trabecular structure of biomimetic fully integrated honeycomb plates.

    Science.gov (United States)

    Chen, Jinxiang; Tuo, Wanyong; Zhang, Xiaoming; He, Chenglin; Xie, Juan; Liu, Chang

    2016-12-01

    To develop lightweight biomimetic composite structures, the compressive failure and mechanical properties of fully integrated honeycomb plates were investigated experimentally and through the finite element method. The results indicated that: fracturing of the fully integrated honeycomb plates primarily occurred in the core layer, including the sealing edge structure. The morphological failures can be classified into two types, namely dislocations and compactions, and were caused primarily by the stress concentrations at the interfaces between the core layer and the upper and lower laminations and secondarily by the disordered short-fiber distribution in the material; although the fully integrated honeycomb plates manufactured in this experiment were imperfect, their mass-specific compressive strength was superior to that of similar biomimetic samples. Therefore, the proposed bio-inspired structure possesses good overall mechanical properties, and a range of parameters, such as the diameter of the transition arc, was defined for enhancing the design of fully integrated honeycomb plates and improving their compressive mechanical properties.

  3. Multifunctional Shielding and Self-Healing HybridSil Smart Composites for Space Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NanoSonic has recently developed multifunctional shielding and self-healing HybridSil (HS) smart composites via the inclusion of innovative nanoshell...

  4. Hybrid Polyvinyl Alcohol and Cellulose Fiber Pulp Instead of Asbestos Fibers in Cement-Based Composites

    Science.gov (United States)

    Shokrieh, M. M.; Mahmoudi, A.; Shadkam, H. R.

    2015-05-01

    The Taguchi method was used to determine the optimum content of a four-parameters cellulose fiber pulp, polyvinyl alcohol (PVA) fibers, a silica fume, and bentonite for cement-based composite sheets. Then cement composite sheets from the hybrid of PVA and the cellulose fiber pulp were manufactured, and their moduli of rapture were determined experimentally. The result obtained showed that cement composites with a hybrid of PVA and cellulose fiber pulp had a higher flexural strength than cellulose-fiber- reinforced cement ones, but this strength was rather similar to that of asbestos-fiber-reinforced cement composites. Also, using the results of flexural tests and an analytical method, the tensile and compressive moduli of the hybrid of PVA and cement sheet were calculated. The hybrid of PVA and cellulose fiber pulp is proposed as an appropriate alternative for substituting asbestos in the Hatschek process.

  5. Hardness and degree of conversion of dental restorative composites based on an organic-inorganic hybrid

    OpenAIRE

    Sandro Aurélio de Souza Venter; Silvia Luciana Fávaro; Eduardo Radovanovic; Emerson Marcelo Girotto

    2013-01-01

    This paper presents a factorial design (mixture design) used to analyze the hardness and degree of monomer conversion into composites containing conventional monomers and an organic-inorganic hybrid polymer-based methacryloyloxypropyl trimethoxysilane (MEMO). For this purpose, resins (composites with SiO2) were formulated with the hybrid polymer (polycondensed, pMEMO), and two conventional monomers used in dentistry, bisphenol-A dimethacrylate (Bis-GMA) and triethyleneglycol dimethacrylate (T...

  6. Mechanical properties of waste paper/jute fabric reinforced polyester resin matrix hybrid composites.

    Science.gov (United States)

    Das, Sekhar

    2017-09-15

    Hybrid composites were prepared with jute fabric and un-shredded newspaper in polyester resin matrix. The experiment was designed 1:2 weights ratio jute and unshredded newspaper to have 42 (w/w)% fibre content hybrid composites and two different sequences jute/paper/jute and paper/jute/paper of waste newspaper and jute fabric arrangement. Reinforcing material is characterized by chemically, X-ray diffraction methods, Fourier transform infrared spectroscopy and tensile testing. The tensile, flexural and interlaminar shear strength and fracture surface morphology of composites were evaluated and compared. It was found that tensile and flexural properties of the hybrid composite are higher than that of pure paper-based composite but less than pure woven jute composite. The hybridization effect of woven jute fabric and layering pattern effect on mechanical properties of newspaper/woven jute fabric hybrid composites were studied. The test results of composites were analyzed by one-way ANOVA (α=0.05), it showed significant differences among the groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Mechanical Behavior of Hybrid Glass/Steel Fiber Reinforced Epoxy Composites

    Directory of Open Access Journals (Sweden)

    Amanda K. McBride

    2017-04-01

    Full Text Available While conventional fiber-reinforced polymer composites offer high strength and stiffness, they lack ductility and the ability to absorb energy before failure. This work investigates hybrid fiber composites for structural applications comprised of polymer, steel fiber, and glass fibers to address this shortcoming. Varying volume fractions of thin, ductile steel fibers were introduced into glass fiber reinforced epoxy composites. Non-hybrid and hybrid composite specimens were prepared and subjected to monolithic and half-cyclic tensile testing to obtain stress-strain relationships, hysteresis behavior, and insight into failure mechanisms. Open-hole testing was used to assess the vulnerability of the composites to stress concentration. Incorporating steel fibers into glass/epoxy composites offered a significant improvement in energy absorption prior to failure and material re-centering capabilities. It was found that a lower percentage of steel fibers (8.2% in the hybrid composite outperformed those with higher percentages (15.7% and 22.8% in terms of energy absorption and re-centering, as the glass reinforcement distributed the plasticity over a larger area. A bilinear hysteresis model was developed to predict cyclic behavior of the hybrid composite.

  8. Synergy effects of hybrid carbon system on properties of composite bipolar plates for fuel cells

    Science.gov (United States)

    Kim, Jong Wan; Kim, Nam Hoon; Kuilla, Tapas; Kim, Tae Jin; Rhee, Kyong Yop; Lee, Joong Hee

    A hybrid carbon system of graphite powder (GP) and continuous carbon fibre fabric (CFF) is used for an epoxy composite to improve the electrical conductivity, mechanical properties and mouldability of a composite bipolar plate. These improvements are achieved simultaneously by inserting several layers of CFF into the GP/epoxy composite to enhance the mechanical properties and in-plane conductivity. The electrical properties, flexural strength and mouldability of the composite plates are measured as a function of conducting filler content and number of CFF layers. The composites show improved electrical conductivity, flexural properties and mouldability. Composites with 70-75 vol.% carbon fillers have the highest electrical conductivity with reasonable flexural properties. These results suggest that the poor mouldability and low through-plane electrical conductivity of the continuous fibre composite bipolar plate, as well as the weak flexural properties of GP composites, can be overcome by incorporating a GP/CFF hybrid system.

  9. Aluminum Honeycomb Characteristics in Dynamic Crush Environments

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, Vesta I.; Swanson, Lloyd H.

    1999-07-01

    Fifteen aluminum honeycomb cubes (3 in.) have been crushed in the Mechanical Shock Laboratory's drop table testing machines. This report summarizes shock experiments with honeycomb densities of 22.1 pcf and 38.0 pcf and with crush weights of 45 lb, 168 lb, and 268 lb. The honeycomb samples were crushed in all three orientations, W, L, and T. Most of the experiments were conducted at an impact velocity of {approx}40 fps, but higher velocities of up to 90 fps were used for selected experiments. Where possible, multiple experiments were conducted for a specific orientation and density of the honeycomb samples. All results are for Hexcel honeycomb except for one experiment with Alcore honeycomb and have been evaluated for validity. This report contains the raw acceleration data measured on the top of the drop table carriage, pictures of the crushed samples, and normalized force-displacement curves for all fifteen experiments. These data are not strictly valid for material characteristics in L and T orientations because the cross-sectional area of the honeycomb changed (split) during the crush. However, these are the best data available at this time. These dynamic crush data do suggest a significant increase in crush strength to 8000 psi ({approximately} 25-30% increase) over quasi-static values of {approximately}6000 psi for the 38.0 pcf Hexcel Honeycomb in the T-orientation. An uncertainty analysis is included and estimates the error in these data.

  10. Biomechanical characteristics of polymeric UHMWPE composites with hybrid matrix and dispersed fillers

    Science.gov (United States)

    Panin, Sergey; Kornienko, Lyudmila; Shilko, Sergey; Thuc, Nguyen Xuan; Korchagin, Mikhail; Chaikina, Marina

    2015-11-01

    In order to develop artificial joint implants some biomechanical properties of composites with UHMWPE and hybrid (polymer-polymeric) "UHMWPE+PTFE" matrix with dispersed fillers were studied. A comparative analysis of the effectiveness of adding hydroxyapatite micron- and nanopowders as a biocompatible filler was carried out. It was shown that under dry sliding friction the wear rate of nanocomposites with the hybrid matrix is lower as compared with composites with the non-hybrid one. Mechanical activation of components further enhances the durability of nano- and microcomposites to almost double it without any significant reduction in the strength characteristics.

  11. Fatigue of hybrid glass/carbon composites: 3D computational studies

    DEFF Research Database (Denmark)

    Dai, Gaoming; Mishnaevsky, Leon

    2014-01-01

    3D computational simulations of fatigue of hybrid carbon/glass fiber reinforced composites is carried out using X-FEM and multifiber unit cell models. A new software code for the automatic generation of unit cell multifiber models of composites with randomly misaligned fibers of various properties...... and geometrical parameters is developed. With the use of this program code and the X-FEM method, systematic investigations of the effect of microstructure of hybrid composites (fraction of carbon versus glass fibers, misalignment, and interface strength) and the loading conditions (tensile versus compression...... cyclic loading effects) on fatigue behavior of the materials are carried out. It was demonstrated that the higher fraction of carbon fibers in hybrid composites is beneficial for the fatigue lifetime of the composites under tension-tension cyclic loading, but might have negative effect on the lifetime...

  12. Flexural, Impact Properties and Sem Analysis of Bamboo and Glass Fiber Reinforced Polyester Hybrid Composites

    Directory of Open Access Journals (Sweden)

    Raghavendra Rao. H

    2014-08-01

    Full Text Available The Flexural, Impact properties and Scanning electron microscope analysis of Bamboo/glass fibers Reinforced polyester Hybrid composites were studied. The effect of alkali treatment of the bamboo fibers on these properties was also studied. It was observed that the Flexural, impact properties of the hybrid composite increase with glass fiber content. These properties found to be higher when alkali treated bamboo fibers were used in the hybrid composites. The elimination of amorphous hemi-cellulose with alkali treated leading to higher crystallinity of the bamboo fibers with alkali treatment may be responsible for these observations. The author investigated the interfacial bonding between Glass/Bamboo reinforced polyester composites. The effect of alkali treatment on the bonding between Glass/Bamboo composites was also studied.

  13. Experimental Investigation on Shear and Hardness of Abaca based Hybrid Composites

    Directory of Open Access Journals (Sweden)

    Vijaya Ramnath B.

    2016-01-01

    Full Text Available Present technology development in the area of materials replaces the conventional materials used in automobile and aerospace sector by composite materials due their less weight and bio degradability. This paper aims to fabricate and investigate the mechanical properties of abaca-raffia hybrid composite fabricated by hand layup process. Since, abaca fiber has more strength than other fibers like kenaf, banana and sisal, the composite with this fiber can be suitable replacement material for automotive applications.The properties like double shear and hardnessare evaluated andthe result shows that the double shear properties and hardness of the hybrid composites [GFRP+Abaca+Raffia] is higher than other two combinations. The internal microstructure of the hybrid composites were analysed using Scanning electron microscope (SEM.

  14. Composite of macroporous carbon with honeycomb-like structure from mollusc shell and NiCo(2)O(4) nanowires for high-performance supercapacitor.

    Science.gov (United States)

    Xiong, Wei; Gao, Yongsheng; Wu, Xu; Hu, Xuan; Lan, Danni; Chen, Yangyang; Pu, Xuli; Zeng, Yan; Su, Jun; Zhu, Zhihong

    2014-01-01

    Novel biological carbon materials with highly ordered microstructure and large pore volume have caused great interest due to their multifunctional properties. Herein, we report the preparation of an interconnected porous carbon material by carbonizing the organic matrix of mollusc shell. The obtained three-dimensional carbon skeleton consists of hexangular and tightly arranged channels, which endow it with efficient electrolyte penetration and fast electron transfer, enable the mollusc shell based macroporous carbon material (MSBPC) to be an excellent conductive scaffold for supercapacitor electrodes. By growing NiCo2O4 nanowires on the obtained MSBPC, NiCo2O4/MSBPC composites were synthesized. When used on supercapacitor electrode, it exhibited anomalously high specific capacitance (∼1696 F/g), excellent rate performance (with the capacity retention of 58.6% at 15 A/g) and outstanding cycling stability (88% retention after 2000 cycles). Furthermore, an all-solid-state symmetric supercapacitor was also assembled based on this NiCo2O4/MSBPC electrode and showed good electrochemical performance with an energy density of 8.47 Wh/kg at 1 A/g, good stability over 10000 cycles. And we believe that more potential applications beyond energy storage can be developed based on this MSBPC.

  15. Hybrid composites - State-of-the-art review: Analysis, design, application and fabrication

    Science.gov (United States)

    Chamis, C. C.; Lark, R. F.

    1977-01-01

    The review covers hybrid composites that consist of two or more different types of fibers (or fiber composites) in a frequently repeated pattern in a laminate. The fibers considered are boron, graphite, glass, and Kevlar; the resins considered include mostly structural epoxies, with some utilization of polyimides and thermoplastics. The review shows that considerable data have been generated for the tensile strength properties, as well as tensile and thermal fatigue, of interply hybrids, and for the impact resistance of interply and intraply hybrids. The rule of mixtures appears to be adequate for predicting longitudinal and transverse mechanical properties of unidirectional interply hybrids, and linear laminate theory appears to be adequate for predicting the elastic response of hybrids.

  16. Media composition influences yeast one- and two-hybrid results

    Directory of Open Access Journals (Sweden)

    Gonzalez Kim L

    2011-08-01

    Full Text Available Abstract Although yeast two-hybrid experiments are commonly used to identify protein interactions, the frequent occurrence of false negatives and false positives hampers data interpretation. Using both yeast one-hybrid and two-hybrid experiments, we have identified potential sources of these problems: the media preparation protocol and the source of the yeast nitrogen base may not only impact signal range but also effect whether a result appears positive or negative. While altering media preparation may optimize signal differences for individual experiments, media preparation must be reported in detail to replicate studies and accurately compare results from different experiments.

  17. Mechanical Properties of Additively Manufactured Thick Honeycombs

    Directory of Open Access Journals (Sweden)

    Reza Hedayati

    2016-07-01

    Full Text Available Honeycombs resemble the structure of a number of natural and biological materials such as cancellous bone, wood, and cork. Thick honeycomb could be also used for energy absorption applications. Moreover, studying the mechanical behavior of honeycombs under in-plane loading could help understanding the mechanical behavior of more complex 3D tessellated structures such as porous biomaterials. In this paper, we study the mechanical behavior of thick honeycombs made using additive manufacturing techniques that allow for fabrication of honeycombs with arbitrary and precisely controlled thickness. Thick honeycombs with different wall thicknesses were produced from polylactic acid (PLA using fused deposition modelling, i.e., an additive manufacturing technique. The samples were mechanically tested in-plane under compression to determine their mechanical properties. We also obtained exact analytical solutions for the stiffness matrix of thick hexagonal honeycombs using both Euler-Bernoulli and Timoshenko beam theories. The stiffness matrix was then used to derive analytical relationships that describe the elastic modulus, yield stress, and Poisson’s ratio of thick honeycombs. Finite element models were also built for computational analysis of the mechanical behavior of thick honeycombs under compression. The mechanical properties obtained using our analytical relationships were compared with experimental observations and computational results as well as with analytical solutions available in the literature. It was found that the analytical solutions presented here are in good agreement with experimental and computational results even for very thick honeycombs, whereas the analytical solutions available in the literature show a large deviation from experimental observation, computational results, and our analytical solutions.

  18. Vibration and Operational Characteristics of a Composite-Steel (Hybrid) Gear

    Science.gov (United States)

    Handschuh, Robert F.; LaBerge, Kelsen E.; DeLuca, Samuel; Pelagalli, Ryan

    2014-01-01

    Hybrid gears have been tested consisting of metallic gear teeth and shafting connected by composite web. Both free vibration and dynamic operation tests were completed at the NASA Glenn Spur Gear Fatigue Test Facility, comparing these hybrid gears to their steel counterparts. The free vibration tests indicated that the natural frequency of the hybrid gear was approximately 800 Hz lower than the steel test gear. The dynamic vibration tests were conducted at five different rotational speeds and three levels of torque in a four square test configuration. The hybrid gears were tested both as fabricated (machined, composite layup, then composite cure) and after regrinding the gear teeth to the required aerospace tolerance. The dynamic vibration tests indicated that the level of vibration for either type of gearing was sensitive to the level of load and rotational speed.

  19. Effect of an Angle-Ply Orientation on Tensile Properties of Kevlar/glass Hybrid Composites

    Directory of Open Access Journals (Sweden)

    Guru Raja M . N

    2013-10-01

    Full Text Available Hybrid composites are considered materials of great potential for engineering applications. One advantage of hybrid composite materials for the designer is that the properties of a composite can be controlled to a considerable extent by the choice of fibers and matrix and by adjusting the orientation of the fiber. The scope for this tailoring of the properties of the material is much greater, however, when different kinds of fiber orientations are incorporated in the same resin matrix. For the study of potential of these materials, in this work specimens were prepared with different angle ply orientation of kevlar/glass hybrid with epoxy resin as an adhesive. Three orientations viz 0/90, 45/45 and 30/60 were considered for studies. Mechanical properties such as tensile strength, tensile modulus, & peak load of the hybrid composites were determined as per ASTM standards. Vacuum bagging technique was adopted for the fabrication of hybrid specimens. It was observed that angle ply orientation at 0/90 showed significant increase in tensile properties as compared to other orientation. Finally, the failure analysis of hybrid composites is also discussed.

  20. Aluminum honeycomb impact limiter study

    Energy Technology Data Exchange (ETDEWEB)

    Yaksh, M.C.; Thompson, T.C. (Nuclear Assurance Corp., Norcross, GA (United States)); Nickell, R.E. (Applied Science and Technology, Inc., Poway, CA (United States))

    1991-07-01

    Design requirements for a cask transporting radioactive materials must include the condition of the 30-foot free fall of the cask onto an unyielding surface. To reduce the deceleration loads to a tolerable level for all the components of the cask, a component (impact limiter) is designed to absorb the kinetic energy. The material, shape, and method of attachment of the impact limiter to the cask body comprises the design of the impact limiter. The impact limiter material of interest is honeycomb aluminum, and the particular design examined was for the NAC Legal Weight Truck cask (NAC-LWT) for spent fuel from light water reactors. The NAC-LWT has a design weight of 52,000 pounds, and it has a nominal length of 200 inches. The report describes the numerical calculations embodied in the FADE program to determine the accelerations and crush strain resulting from an arbitrary height and angle of orientation. Since the program serves as a design tool, static tests are performed to assess the effect of the shell containing the honeycomb aluminum. The static tests and their results are contained in the study. The static tests are used to demonstrate for licensing purposes the level of accelerations imposed on the cask during a 30-foot drop. 3 refs., 41 figs., 15 tabs.

  1. Combination of plasma with a honeycomb-structured catalyst for automobile exhaust treatment.

    Science.gov (United States)

    Kang, Woo Seok; Lee, Dae Hoon; Lee, Jae-Ok; Hur, Min; Song, Young-Hoon

    2013-10-01

    To activate a catalyst efficiently at low temperature by plasma for environmental control, we developed a hybrid reactor that combines plasma with a honeycomb-structured catalyst in a practical manner. The reactor developed generated stable cold plasma at atmospheric pressure because of the dielectric and conductive nature of the honeycomb catalyst by consuming low amounts of power. In this reactor, the applied voltage and temperature determined the balance between the oxidation and adsorption by the plasma and catalyst. The synergistic reaction of the plasma and catalyst was more effective at low temperatures, resulting in a reduction in a lowered light-off temperature.

  2. Nuclear and cytoplasmic genome composition of Solanum bulbocastanum (+) S. tuberosum somatic hybrids.

    Science.gov (United States)

    Iovene, Marina; Savarese, Salvatore; Cardi, Teodoro; Frusciante, Luigi; Scotti, Nunzia; Simon, Philipp W; Carputo, Domenico

    2007-05-01

    Somatic hybrids between the wild incongruent species Solanum bulbocastanum (2n = 2x = 24) and S. tuberosum haploids (2n = 2x = 24) have been characterized for their nuclear and cytoplasmic genome composition. Cytologic observations revealed the recovery of 8 (near-)tetraploid and 3 hexaploid somatic hybrids. Multicolor genomic in situ hybridization (GISH) analysis was carried out to study the genomic dosage of the parental species in 5 somatic hybrids with different ploidy. The GISH procedure used was effective in discriminating parental genomes in the hybrids; most chromosomes were unambiguously colored. Two (near-)tetraploid somatic hybrids showed the expected 2:2 cultivated-to-wild genomic dosage; 2 hexaploids revealed a 4:2 cultivated-to-wild genomic dosage, and 1 hexaploid had a 2:4 cultivated-to-wild genomic dosage. Characterization of hybrid cytoplasmic genomes was performed using gene-specific primers that detected polymorphisms between the fusion parents in the intergenic regions. The analysis showed that most of the somatic hybrids inherited the plastidial and mitochondrial DNA of the cultivated parent. A few hybrids, with a rearranged mitochondrial genome (showing fragments derived from both parents), were also identified. These results confirmed the potential of somatic hybridization in producing new variability for genetic studies and breeding.

  3. Tensile and Compressive Properties of Woven Kenaf/Glass Sandwich Hybrid Composites

    Directory of Open Access Journals (Sweden)

    Mohaiman J. Sharba

    2016-01-01

    Full Text Available Monotonic (tensile and compression properties of woven kenaf/glass reinforced unsaturated polyester sandwich hybrid composites have been experimentally investigated. Five types of composites laminates were fabricated using a combination of hand lay-up and cold press techniques, postcured for two hours at 80°C and left for 48 hours at room temperature. The hybrid composites contained fixed six layers of glass as a shell, three on each side, whereas the number of core kenaf layers was changed in three stages to get S1, S2, and S3 hybrid composites. Composites specimens with pure glass and kenaf were also fabricated for comparison. It was found that one kenaf layer replaced about 20% of total fiber weight fraction of the composite; this leads to reducing the density of final hybrid composite by 13%. Besides, in mechanical properties perspective, there are less than 1% reduction in compression strength and 40% in tensile strength when compared to pure glass composite. Generally, the results revealed that the best performance was observed in S1, which showed a good balance of all mechanical properties determined in this work.

  4. Piezoelectric properties of the new generation active matrix hybrid (micro-nano) composites

    Science.gov (United States)

    Parali, Levent; Şabikoğlu, İsrafil; Kurbanov, Mirza A.

    2014-11-01

    A hybrid piezoelectric composite structure is obtained by addition of nano-sized BaTiO3, SiO2 to the micro-sized PZT and polymers composition. Although the PZT material itself has excellent piezoelectric properties, PZT-based composite variety is limited. Piezoelectric properties of PZT materials can be varied with an acceptor or a donor added to the material. In addition, varieties of PZT-based sensors can be increased with doping polymers which have physical-mechanical, electrophysical, thermophysical and photoelectrical properties. The active matrix hybrid structure occurs when bringing together the unique piezoelectric properties of micro-sized PZT with electron trapping properties of nano-sized insulators (BaTiO3 or SiO2), and their piezoelectric, mechanic and electromechanic properties significantly change. In this study, the relationship between the piezoelectric constant and the coupling factor values of microstructure (PZT-PVDF) and the hybrid structure (PZT-PVDF-BaTiO3) composite are compared. The d33 value and the coupling factor of the hybrid structure have shown an average of 54 and 62% increase according to microstructure composite, respectively. In addition, the d33 value and the coupling factor of the hybrid structure (PZT-HDPE-SiO2) have exhibited about 68 and 52% increase according to microstructure composite (PZT-HDPE), respectively.

  5. Dynamic Buffering Performance of the Honeycomb Paperboard Filled with Polyurethane

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong; XIE Weihong; CHEN Li

    2014-01-01

    A new kind of composite buffering material was made by filling the voids of honeycomb paperboard with polyurethane. Drop tests were performed to evaluate the dynamic energy absorption capacity of the material. Based on the tests results, we analyzed the mechanical behaviors of the material under different conditions and obtained the inherent influencing laws of some factors on the material’s dynamic buffering performance. It was shown that the dynamic buffering performance varied directly with impact velocity, and inversely with the void diameter, thickness and buffering area of the composite material.

  6. A honeycomb network based on hybrid lanthanum complexes encircling a [β-Mo8O26]4- isomer: Synthesis, characterization and crystal structure of [La (η2-NO3) (dmso)7]2 [β-Mo8O26

    Science.gov (United States)

    Khélifa, Arbia Ben; Ezzayani, Khaireddine; Belkhiria, Mouhamed Salah

    2016-10-01

    A novel isopolymolybdates functionalized by rare earth complexes namely, [La (η2-NO3) (dmso)7]2 [β-Mo8O26] (1) has been successfully synthesized and characterized by routine methods: IR, X-ray powder diffraction, UV-Visible absorption and single crystal X-ray diffraction. The title compound is crystallized in monoclinic space group P21/n with a = 11.566 (2) Å, b = 28.522 (6) Å, c = 12.644 (3) Å, β = 91.94 (3)°. The structural feature of 1 is that lanthanum complexes form a honeycomb network, in which resides the [β-Mo8O26]4- isomer. The cohesion structure is ensured by non typical hydrogen bonding interactions causes a 3D supramolecular network. Absorption spectrum, optical band gap energies have been investigated.

  7. Carbon nanotube reinforced hybrid composites: Computational modeling of environmental fatigue and usability for wind blades

    DEFF Research Database (Denmark)

    Dai, Gaoming; Mishnaevsky, Leon

    2015-01-01

    The potential of advanced carbon/glass hybrid reinforced composites with secondary carbon nanotube reinforcement for wind energy applications is investigated here with the use of computational experiments. Fatigue behavior of hybrid as well as glass and carbon fiber reinforced composites...... with and without secondary CNT reinforcement is simulated using multiscale 3D unit cells. The materials behavior under both mechanical cyclic loading and combined mechanical and environmental loading (with phase properties degraded due to the moisture effects) is studied. The multiscale unit cells are generated...... with the secondary CNT reinforcements (especially, aligned tubes) present superior fatigue performances than those without reinforcements, also under combined environmental and cyclic mechanical loading. This effect is stronger for carbon composites, than for hybrid and glass composites....

  8. Performance Investigation of a Full-Scale Hybrid Composite Bull Gear

    Science.gov (United States)

    LaBerge, Kelsen; Handschuh, Robert; Roberts, Gary; Thorp, Scott

    2016-01-01

    Hybrid composite gears have been investigated as a weight saving technology for rotorcraft transmissions. These gears differ from conventional steel gears in that the structural material between the shaft interface and the gear rim is replaced with a lightweight carbon fiber composite. The work discussed here is an extension of previous coupon level hybrid gear tests to a full-scale bull gear. The NASA Glenn Research Center High-Speed Helical Gear Rig was modified for this program allowing several hybrid gear web configurations to be tested while utilizing the same gear rim. Testing was performed on both a baseline (steel) web configuration and a hybrid (steel-composite)configuration. Vibration, orbit and temperature data were recorded and compared between configurations. Vibration levels did not differ greatly between the hybrid and steel configurations, nor did temperature differential between inlet and outlet. While orbit shape displayed differences between the hybrid and baseline configurations, the general overall amplitude was comparable. The hybrid configuration discussed here successfully ran at 3300 hp(2,460 kW), however, progressive growth of the orbit while running at this test condition discontinued the test. Researchers continue to search for the cause of this orbit shift.

  9. Performance Investigation of a Full-Scale Hybrid Composite Bull Gear

    Science.gov (United States)

    Laberge, Kelsen E.; Handschuh, Robert F.; Roberts, Gary; Thorp, Scott

    2016-01-01

    Hybrid composite gears have been investigated as a weight saving technology for rotorcraft transmissions. These gears differ from conventional steel gears in that the structural material between the shaft interface and the gear rim is replaced with a lightweight carbon fiber composite. The work discussed here is an extension of previous coupon level hybrid gear tests to a full-scale bull gear. The NASA Glenn Research Center High-Speed Helical Gear Rig was modified for this program, allowing several hybrid gear web configurations to be tested while utilizing the same gear rim. Testing was performed on both a baseline (steel) web configuration and a hybrid (steel-composite) configuration. Vibration, orbit and temperature data were recorded and compared between configurations. Vibration levels did not differ greatly between the hybrid and steel configurations, nor did temperature differential between inlet and outlet. While orbit shape displayed differences between the hybrid and baseline configurations, the general overall amplitude was comparable. The hybrid configuration discussed here successfully ran at 3300 hp (2,460 kW), however, progressive growth of the orbit while running at this test condition discontinued the test. Further studies are planned to determine the cause of this behavior.

  10. Characterization of hybrid aluminum matrix composites for advanced applications – A review

    Directory of Open Access Journals (Sweden)

    Jaswinder Singh

    2016-04-01

    Full Text Available Hybrid aluminum matrix composites (HAMCs are the second generation of composites that have potential to substitute single reinforced composites due to improved properties. This paper investigates the feasibility and viability of developing low cost-high performance hybrid composites for automotive and aerospace applications. Further, the fabrication characteristics and mechanical behavior of HAMCs fabricated by stir casting route have also been reviewed. The optical micrographs of the HAMCs indicate that the reinforcing particles are fairly distributed in the matrix alloy and the porosity levels have been found to be acceptable for the casted composites. The density, hardness, tensile behavior and fracture toughness of these composites have been found to be either comparable or superior to the ceramic reinforced composites. It has been observed from the literature that the direct strengthening of composites occurs due to the presence of hard ceramic phase, while the indirect strengthening arises from the thermal mismatch between the matrix alloy and reinforcing phase during solidification. Based on the database for material properties, the application area of HAMCs has been proposed in the present review. It has been concluded that the hybrid composites offer more flexibility and reliability in the design of possible components depending upon the reinforcement's combination and composition.

  11. Hertzian Load-bearing Capacity of Hybrid and Nano-hybrid Resin Composites Stored Dry and Wet

    Directory of Open Access Journals (Sweden)

    Farmani S

    2016-03-01

    Full Text Available Statement of Problem: Hertzian indentation test has been proven to be an efficient and reliable alternative upon Vickers hardness test. This method has been used to test dental ceramics, amalgams, glass ionomers and luting cements.There is limited published information about the load-bearing capacity of resin composites using Hertizian indentation test. Objectives: To investigate the load-bearing capacity of hybrid and nano-hybrid resin composites stored dry or wet up to 30 days, using Hertzian indentation test. Materials and Methods: Three resin composites were used: two nano-hybrids (Filtek Supreme, and Luna and one hybrid, (Rok. A total of 108 disc-shaped specimens (1mm thick x 10 mm diameter were prepared using polyethylene mould. The specimens of each material were randomly divided into 6 groups of 6 (n=6 and stored at 370C either in distilled water or dry for 1, 7 and 30 days. The specimens were tested using Hertzian jig aligned in the universal testing machine. The specimen was placed on the top of a disc-shaped substrate. The load was applied at the center of each specimen and the load at the first crack was recorded. Data were analyzed by ANOVA, Tukey’sand student’s t-test using SPSS version 18.0. Results: Three-way ANOVA showed a significant interaction between all the factors (p = .0001. The load bearing capacity of almost all materials reduced significantly in the wet condition in comparison with the dry condition (p = .0001. After seven days of immersion in distilled water, Filtek Supreme had significantly lower values than those of Rok and Luna, there was no significant differences between materials in the dry condition. Conclusions:In contrast to dry condition, the load-bearing capacity of specimens stored in distilled water decreased significantly over the 30 days of immersion. The load bearing capacity of nano-hybrid composites tested in this study was shown to be comparable with that of the hybrid composite.

  12. Solid Particle Erosion response of fiber and particulate filled polymer based hybrid composites: A review

    Directory of Open Access Journals (Sweden)

    Yogesh M

    2016-01-01

    Full Text Available The solid particle erosion behaviour of fiber and particulate filled polymer composites has been reviewed. An overview of the problem of solid particle erosion was given with respect to the processes and modes during erosion with focus on polymer matrix composites. The new aspects in the experimental studies of erosion of fiber and particulate filled polymer composites were emphasized in this paper. Various predictions and models proposed to describe the erosion rate were listed and their suitability was mentioned. Implementation of design of experiments and statistical techniques in analyzing the erosion behaviour of composites was discussed. Recent findings on erosion response of multi-component hybrid composites were also presented. Recommendations were given on how to solve some open questions related to the structureerosion resistance relationships for polymers and polymer based hybrid composites.

  13. Environmental effects on the hybrid glass fiber/carbon fiber composites

    Science.gov (United States)

    Tsai, Yun-I.

    2009-12-01

    Fiber reinforced polymer composites (FRPCs) have been widely used to replace conventional metals due to the high specific strength, fatigue resistance, and light weight. In the power distribution industry, an advanced composites rod has been developed to replace conventional steel cable as the load-bearing core of overhead conductors. Such conductors, called aluminum conductor composite core (ACCC) significantly increases the transmitting efficiency of existing power grid system without extensive rebuilding expenses, while meeting future demand for electricity. In general, the service life of such overhead conductors is required to be at least 30 years. Therefore, the long-term endurance of the composite core in various environments must be well-understood. Accelerated aging by hygrothermal exposure was conducted to determine the effect of moisture on the glass fiber (GF)/carbon fiber (CF) hybrid composites. The influence of water immersion and humid air exposure on mechanical properties is investigated. Results indicated that immersion in water is the most severe environment for such hybrid GF/CF composites, and results in greater saturation and degradation of properties. When immersed directly in water, the hybrid GF/CF composites exhibit a moisture uptake behavior that is more complex than composite materials reinforced with only one type of fiber. The unusual diffusion behavior is attributed to a higher packing density of fibers at the annular GF/CF interface, which acts as a temporary moisture barrier. Moisture uptake leads to the mechanical and thermal degradation of such hybrid GF/CF composites. Findings presented here indicate that the degradation is a function of exposure temperature, time, and moisture uptake level. Results also indicate that such hybrid GF/CF composites recover short beam shear (SBS) strength and glass transition temperature (Tg) values comparable to pre-aged samples after removal of the absorbed moisture. In the hygrothermal environment

  14. STUDY AND FABRICATION OF SOYBEAN- KEVLAR HYBRID COMPOSITE MATERIAL

    OpenAIRE

    Dilip M R*, Dr. B R Narendra Babu

    2016-01-01

    The prerequisite for most outstanding and normal composite materials to be delivered or recognized, having eco-pleasing ascribes and have ability to acclimate to trademark changes happening on regular calendar, has passed on individuals to find new sources and variety of composite materials to be made. At the present age, trademark fiber composites having near properties, from renewable normal resources expect a vital part in course of action of composite material when diverged from man-made ...

  15. Investigation on mechanical properties of woven alovera/sisal/kenaf fibres and their hybrid composites

    Indian Academy of Sciences (India)

    K PALANI KUMAR; A SHADRACH JEYA SEKARAN; K PITCHANDI

    2017-02-01

    The go-green concept results in multipoint focus towards materials made from nature; easily decomposable and recyclable polymeric materials and their composites along with natural fibres ignited the manufacturing sectors to go for higher altitudes in engineering industries. This is due to the health hazard and environmental problems faced in manufacturing and disposal of synthetic fibres. This study was undertaken to analyse the suitability of new natural fibre as an alternative reinforcement for composite materials. In this paper, tensile, flexural and impact test is made for the woven alovera and kenaf (AK), sisal and kenaf (SK), alovera, sisal and kenaf fibre hybrid epoxy composites (ASK). The composite laminates are made through a hand-layup process. The surface analysis is studied through scanning electron microscopy. From the investigation the SK hybrid composite shows good tensile property, AK hybrid composite shows better flexural property and the best impact strength is observed for ASK hybrid composite. The natural fibres slowly replace the synthetic fibres from its environmental impact, marching towards a revolution in engineering materials.

  16. Experimental Investigation on Shear and Hardness of Abaca based Hybrid Composites

    OpenAIRE

    Vijaya Ramnath B.; Elanchezhian C.; Manickavasagam V.M.; Gowri Prasad S.; Arvindh Swamy S.; Keshav Raj R.

    2016-01-01

    Present technology development in the area of materials replaces the conventional materials used in automobile and aerospace sector by composite materials due their less weight and bio degradability. This paper aims to fabricate and investigate the mechanical properties of abaca-raffia hybrid composite fabricated by hand layup process. Since, abaca fiber has more strength than other fibers like kenaf, banana and sisal, the composite with this fiber can be suitable replacement material for aut...

  17. Effect of natural fibers and bio-resins on mechanical properties in hybrid and non-hybrid composites

    Science.gov (United States)

    Fragassa, Cristiano

    2016-05-01

    The aim of the present experimental investigation was to perform a comparative analysis concerning the influence on mechanical properties of natural fibers and/or bio-resins in reinforced thermoset composites. Flax and basalt fibers were selected as natural reinforcements, as single constituents or in hybrid combination. Glass synthetic fibers were used for comparison. Eco-friendly matrixes, both epoxy or vinylester, were considered and compared with composites based on traditional resins. Samples were fabricated by hand lay-up and resin infusion techniques. Cures were accelerated and controlled by applying heat and pressure in autoclave. Tensile, flexural and impact tests were carried out according to ASTM standards.

  18. Hybrid Gear Preliminary Results-Application of Composites to Dynamic Mechanical Components

    Science.gov (United States)

    Handschuh, Robert F.; Roberts Gary D.; Sinnamon, R.; Stringer, David B.; Dykas, Brian D.; Kohlman, Lee W.

    2012-01-01

    Composite spur gears were fabricated and then tested at NASA Glenn Research Center. The composite material served as the web of the gear between the gear teeth and a metallic hub for mounting to the torque-applying shaft. The composite web was bonded only to the inner and outer hexagonal features that were machined from an initially all-metallic aerospace quality spur gear. The Hybrid Gear was tested against an all-steel gear and against a mating Hybrid Gear. As a result of the composite to metal fabrication process used, the concentricity of the gears were reduced from their initial high-precision value. Regardless of the concentricity error, the hybrid gears operated successfully for over 300 million cycles at 10000 rpm and 490 in.*lbs torque. Although the design was not optimized for weight, the composite gears were found to be 20% lighter than the all-steel gears. Free vibration modes and vibration/noise tests were also conduct to compare the vibration and damping characteristic of the Hybrid Gear to all-steel gears. The initial results indicate that this type of hybrid design may have a dramatic effect on drive system weight without sacrificing strength.

  19. Heisenberg Honeycombs Solve Veneziano Puzzle

    CERN Document Server

    Kholodenko, A L

    2006-01-01

    In this paper we reformulate some results obtained by Heisenberg into modern mathematical language of honeycombs. This language was developed in connection with complete solution of the Horn conjecture problem. Such a reformulation is done with the purpose of posing and solving the following problem. Is by analysing the (spectroscopic) experimental data it possible to restore the underlying microscopic physical model generating these data? Development of Heisenberg's ideas happens to be the most useful for this purpose. Solution is facilitated by our earlier developed string-theoretic formalism. In this paper only qualitative arguments are presented (with few exceptions). These arguments provide enough evidence that the underelying microscopic model compatible with Veneziano-type amplitudes is the standard (i.e. non supersymmetric!) QCD. In addition, usefulness of the formalism is illustrated on numerous examples such as physically motivated solution of the saturation conjecture, derivation of the Yang-Baxter...

  20. Composite Organic Radical - Inorganic Hybrid Cathode for Lithium-ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qian; Cosimbescu, Lelia; Koech, Phillip K.; Choi, Daiwon; Lemmon, John P.

    2013-07-01

    A new organic radical inorganic hybrid cathode comprised of PTMA/LiFePO4 composite system is developed and reported for the first time. The hybrid cathodes demonstrate high pulse power capability resulting in a significant improvement over the pure PTMA or LiFePO4 cathode which is very promising for transportation and other high pulse power applications that require long cycle life and lower cost.

  1. Fatty acid composition of maize germ oil from high-oil hybrids wet-milling processing

    Directory of Open Access Journals (Sweden)

    Jovanović Petar Lj.

    2005-01-01

    Full Text Available Maize germ was obtained by wet-milling laboratory processing of domestic high-oil maize hybrids. After separation, the germ was subjected to extraction of maize oil. Fatty acid composition of maize germ oil was determined by gas chromatography. The results showed very high levels of unsaturated fatty acids and a constant sum of oleic and linoleic acids in oils of different maize hybrids.

  2. Experimental Test of Stainless Steel Wire Mesh and Aluminium Alloy With Glass Fiber Reinforcement Hybrid Composite

    Directory of Open Access Journals (Sweden)

    Ranga Raj R.,

    2015-05-01

    Full Text Available At present, composite materials are mostly used in aircraft structural components, because of their excellent properties like lightweight, high strength to weight ratio, high stiffness, and corrosion resistance and less expensive. In this experimental work, the mechanical properties of laminate, this is reinforced with stainless steel wire mesh, aluminum sheet metal, perforated aluminum sheet metal and glass fibers to be laminate and investigated. The stainless steel wire mesh and perforated aluminum metal were sequentially stacked to fabricate, hybrid composites. The aluminum metal sheet is also employed with that sequence to get maximum strength and less weight. The tensile, compressive and flexure tests carried out on the hybrid composite. To investigate the mechanical properties and elastic properties of the metal matrix composite laminate of a material we are using experimental test and theoretical calculation. The experimental work consists of Tensile, compressive and flexural test. The expectation of this project results in the tensile and compressive properties of this hybrid composite it is slightly lesser than carbon fibers but it could facilitate a weight reduction compared with CFRP panels. So this hybrid laminates composite material offering significant weight savings and maximum strength over some other GFRP conventional panels.

  3. THERMOMECHANICAL PROPERTIES OF JUTE/BAGASSE HYBRID FIBRE REINFORCED EPOXY THERMOSET COMPOSITES

    Directory of Open Access Journals (Sweden)

    Sudhir Kumar Saw

    2009-11-01

    Full Text Available Natural fibres are partly replacing currently used synthetic fibres as reinforcement for polymer composites. Jute fibre bundles were high-cellulose-content modified by alkali treatment, while the bagasse fibre bundles were modified by creating quinones in the lignin portions of fibre surfaces and reacting them with furfuryl alcohol (FA to increase their adhesiveness. The effects of different fibre bundle loading and modification of bagasse fibre surfaces in hybrid fibre reinforced epoxy composites have been studied. The role of fibre/matrix interactions in chemically modified hybrid composites were investigated using Differential Scanning Calorimeter, Differential Thermo Gravimetry, and a Universal Tensile Machine and compared with those of unmodified bagasse fibre bundles incorporated with modified jute fibre bundles reinforced hybrid composites. Fibre surface modification reduced the hydrophilicity of fibre bundles, and significantly increased mechanical properties of hybrid composites were observed in conjunction with SEM images. The SEM analysis of the fibre and the composite fractured surfaces have confirmed the FA grafting and shown a better compatibility at the interface between chemically modified fibre bundles and epoxy resin. This paper incorporates interesting results of thermomechanical properties and evaluation of fibre/matrix interactions.

  4. Insight into octoploid strawberry (Fragaria) subgenome composition revealed by GISH analysis of pentaploid hybrids.

    Science.gov (United States)

    Liu, Bo; Poulsen, Elizabeth G; Davis, Thomas M

    2016-02-01

    As the product of interspecific hybridization between its two ancestral octoploid (2n = 8x = 56) species (Fragaria chiloensis and F. virginiana), the cultivated strawberry (F. ×ananassa) is among the most genomically complex of crop plants, harboring subgenomic components derived from as many as four different diploid ancestors. To physically visualize the octoploids' subgenome composition(s), we launched molecular cytogenetic studies using genomic in situ hybridization (GISH), comparative GISH (cGISH), and rDNA-FISH techniques. First, GISH resolution in Fragaria was tested by using diploid and triploid hybrids with predetermined genome compositions. Then, observation of an octoploid genome was implemented by hybridizing chromosomes of pentaploid (2n = 5x = 35) hybrids from F. vesca × F. virginiana with genomic DNA probes derived from diploids (2n = 2x = 14) F. vesca and F. iinumae, which have been proposed by phylogenetic studies to be closely related to the octoploids yet highly divergent from each other. GISH and cGISH results indicated that octoploid-derived gametes (n = 4x = 28) carried seven chromosomes with hybridization affinities to F. vesca, while the remaining 21 chromosomes displayed varying affinities to F. iinumae, indicating differing degrees of subgenomic contribution to the octoploids by these two putatively ancestral diploids. Combined rDNA-FISH revealed severe 25S rDNA loss in both the F. vesca- and F. iinumae-like chromosome groups, while only the prior group retained its 5S loci.

  5. Composite Strain Hardening Properties of High Performance Hybrid Fibre Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Vikram Jothi Jayakumar

    2014-01-01

    Full Text Available Hybrid fibres addition in concrete proved to be a promising method to improve the composite mechanical properties of the cementitious system. Fibre combinations involving different fibre lengths and moduli were added in high strength slag based concrete to evaluate the strain hardening properties. Influence of hybrid fibres consisting of steel and polypropylene fibres added in slag based cementitious system (50% CRL was explored. Effects of hybrid fibre addition at optimum volume fraction of 2% of steel fibres and 0.5% of PP fibres (long and short steel fibre combinations were observed in improving the postcrack strength properties of concrete. Test results also indicated that the hybrid steel fibre additions in slag based concrete consisting of short steel and polypropylene (PP fibres exhibited a the highest compressive strength of 48.56 MPa. Comparative analysis on the performance of monofibre concrete consisting of steel and PP fibres had shown lower residual strength compared to hybrid fibre combinations. Hybrid fibres consisting of long steel-PP fibres potentially improved the absolute and residual toughness properties of concrete composite up to a maximum of 94.38% compared to monofibre concrete. In addition, the relative performance levels of different hybrid fibres in improving the matrix strain hardening, postcrack toughness, and residual strength capacity of slag based concretes were evaluated systematically.

  6. Characterization of Nuclear and Cytoplasmic Compositions of Somatic Hybrid Plants Between Sweet Orange and Sour Orange

    Institute of Scientific and Technical Information of China (English)

    LIUJi-Hong; XUXiao-Yong; DENGXiu-Xin

    2004-01-01

    Abstract In the present research, flow cytometry (FCM), simple sequence repeat (SSR) and cleavedamplified polymorphic sequence (CAPS) were employed to analyze somatic hybrid plants derived from electrofusion between embryogenic protoplasts of sweet orange (Citrus sinensis Osbeck cv. Shamouti) and leaf-derived protoplasts of sour orange (C. aurantium L). FCM showed that all of the somatic hybrid plants had two-fold fluorescence intensity values of the diploid control, indicating that they were tetraploids. SSR and CAPS were used to characterize the compositions of nuclear and cytoplasmic genomes of the somatic hybnd plants. As for SSR four primer pairs were tried and two showed polymorphisms between the fusion parents. With both pnmer pairs the somatic hybrid plants encompassed DNA bands from both parents, indicating that they were heterokaryonic hybrids. Amplification with some universal primers, followed by digestion with restriction endonucleases, could distinguish the fusion parents from each other. As far as mitochondrial and chloroplast DNA compositions were concerned the somatic hybrid plants shared the same banding patterns as the embryogenic parents for all of the polymorphic primer/enzyme combinations. The results herein demonstrated that the somatic hybrid plants inherited their nuclear genome from both fusion parents, whereas the cytoplasmic genomes were possibly only contributed by the embryogenic parent. Merits of the analytical methods and nuclear and cytoplasmic inheritance of citrus tetraploid somatic hybrids, together with their application, are discussed herein.

  7. Properties of glass/carbon fiber reinforced epoxy hybrid polymer composites

    Science.gov (United States)

    Patel, R. H.; Sevkani, V. R.; Patel, B. R.; Patel, V. B.

    2016-05-01

    Composite Materials are well known for their tailor-made properties. For the fabrication of composites different types of reinforcements are used for different applications. Sometimes for a particular application, one type of reinforcement may not fulfill the requirements. Therefore, more than one type of reinforcements may be used. Thus, the idea of hybrid composites arises. Hybrid composites are made by joining two or more different reinforcements with suitable matrix system. It helps to improve the properties of composite materials. In the present work glass/carbon fiber reinforcement have been used with a matrix triglycidyl ether of tris(m-hydroxy phenyl) phosphate epoxy resin using amine curing agent. Different physical and mechanical properties of the glass, carbon and glass/carbon fiber reinforced polymeric systems have been found out.

  8. Finite Element Analysis of Adaptive-Stiffening and Shape-Control SMA Hybrid Composites

    Science.gov (United States)

    Gao, Xiujie; Burton, Deborah; Turner, Travis L.; Brinson, Catherine

    2005-01-01

    Shape memory alloy hybrid composites with adaptive-stiffening or morphing functions are simulated using finite element analysis. The composite structure is a laminated fiber-polymer composite beam with embedded SMA ribbons at various positions with respect to the neutral axis of the beam. Adaptive stiffening or morphing is activated via selective resistance heating of the SMA ribbons or uniform thermal loads on the beam. The thermomechanical behavior of these composites was simulated in ABAQUS using user-defined SMA elements. The examples demonstrate the usefulness of the methods for the design and simulation of SMA hybrid composites. Keywords: shape memory alloys, Nitinol, ABAQUS, finite element analysis, post-buckling control, shape control, deflection control, adaptive stiffening, morphing, constitutive modeling, user element

  9. Electrical anisotropy in multiscale nanotube/fiber hybrid composites

    Science.gov (United States)

    Thostenson, Erik T.; Gangloff, John J.; Li, Chunyu; Byun, Joon-Hyung

    2009-08-01

    This letter reports an experimental and theoretical study on the electrical properties of carbon nanotube/glass fiber composites. Experimental measurements on unidirectional glass fiber composites with nanotubes dispersed in the polymer matrix show a high degree of anisotropy. The composites, manufactured with a vacuum infusion technique, do not show any significant process-induced anisotropy. Theoretical modeling reveals that the microstructure of the fiber composite plays a dominant role in the electrical behavior due to alteration of percolating paths in the carbon nanotube network.

  10. Thermal, mechanical, and physical properties of seaweed/sugar palm fibre reinforced thermoplastic sugar palm Starch/Agar hybrid composites.

    Science.gov (United States)

    Jumaidin, Ridhwan; Sapuan, Salit M; Jawaid, Mohammad; Ishak, Mohamad R; Sahari, Japar

    2017-04-01

    The aim of this research is to investigate the effect of sugar palm fibre (SPF) on the mechanical, thermal and physical properties of seaweed/thermoplastic sugar palm starch agar (TPSA) composites. Hybridized seaweed/SPF filler at weight ratio of 25:75, 50:50 and 75:25 were prepared using TPSA as a matrix. Mechanical, thermal and physical properties of hybrid composites were carried out. Obtained results indicated that hybrid composites display improved tensile and flexural properties accompanied with lower impact resistance. The highest tensile (17.74MPa) and flexural strength (31.24MPa) was obtained from hybrid composite with 50:50 ratio of seaweed/SPF. Good fibre-matrix bonding was evident in the scanning electron microscopy (SEM) micrograph of the hybrid composites' tensile fracture. Fourier transform infrared spectroscopy (FT-IR) analysis showed increase in intermolecular hydrogen bonding following the addition of SPF. Thermal stability of hybrid composites was enhanced, indicated by a higher onset degradation temperature (259°C) for 25:75 seaweed/SPF composites than the individual seaweed composites (253°C). Water absorption, thickness swelling, water solubility, and soil burial tests showed higher water and biodegradation resistance of the hybrid composites. Overall, the hybridization of SPF with seaweed/TPSA composites enhances the properties of the biocomposites for short-life application; that is, disposable tray, plate, etc.

  11. Properties of honeycomb polyester knitted fabrics

    Science.gov (United States)

    Feng, A. F.

    2016-07-01

    The properties of honeycomb polyester weft-knitted fabrics were studied to understand their advantages. Seven honeycomb polyester weft-knitted fabrics and one common polyester weft-knitted fabric were selected for testing. Their bursting strengths, fuzzing and pilling, air permeability, abrasion resistance and moisture absorption and perspiration were studied. The results show that the honeycomb polyester weft-knitted fabrics have excellent moisture absorption and liberation. The smaller their thicknesses and area densities are, the better their moisture absorption and liberation will be. Their anti-fuzzing and anti-pilling is good, whereas their bursting strengths and abrasion resistance are poorer compared with common polyester fabric's. In order to improve the hygroscopic properties of the fabrics, the proportion of the honeycomb microporous structure modified polyester in the fabrics should not be less than 40%.

  12. Electrical Resistance Behavior of Vinylester Composites Filled with Glass-carbon Hybrid Fibers

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; ZHANG Lianmeng; XU Renxin; DUAN Huajun; YANG Xiaoli; WANG Xiang

    2009-01-01

    Vinylester (bismethacryloxy derivative of a bisphenol-A type EP resin, VE) composites with glass-carbon hybrid fibers (CF-GF) weight fraction of 50%, were prepared by the compress molding method. The distribution of carbon fiber in the hybrids was observed by stereomicroscope. The electrical resistance behavior of the composites filled with different carbon fiber (CF) weight contents (0.5% to 20%) was studied. The experimental results show that the electrical resistance behaviors of CF-GF/VE composites are different with those of CF/VE composites because carbon fibers' conducting networks are broken by the glass fibers in the CF-GF/VE composites. The carbon fibers distribute uniformly in the networks of glass fibers (GF) like single silk and form the semi-continuous conducting networks. Composite filled with GF-CF hybrid has a higher percolation threshold than that filled with pure CF. At that time, the resistivity of CF-GF/VE composites varies little with the temperature increasing. The temperature coefficient of resistivity in GF-CF/VE composite is less than 317 ppm and the variation of the resistivity after ten thermal cycles from 20 ℃to 240 ℃ is less than 1.96%.

  13. MECHANICAL BEHAVIOUR OF ABACA-GLASS-BANANA FIBRE REINFORCED HYBRID COMPOSITES

    Directory of Open Access Journals (Sweden)

    H. VENKATASUBRAMANIAN

    2015-08-01

    Full Text Available Hybrid composites comprising of natural and synthetic fibres with phenolic resin is one of the present composite manufacturing techniques for achieving enhanced mechanical properties. In this study Abaca-banana-glass composites has been fabricated and its mechanical properties were analysed. Tensile, flexural and impact strength were investigated in the process of mechanical characterisation. Matrix material used is a phenolic resin of Ortho-Phthalic acid. The manufacture of the composite is done by hand layup technique where the fibre content is varied through volume fraction of 0.4 to 0.5. Setup is arranged in such a way that glass fibre is arranged on the top and bottom layers of the laminate which adds up strength and produces a better surface finish, where in the natural fibre is sandwiched in intermediate layers within the glass fibre. Fibre orientation and the detailed internal structure of matrix were studied by using SEM photography. The results showed that Abaca-banana-glass hybrid composite has better tensile property, Banana-glass composite has the best flexural property and Abaca-glass composite has the best impact property. The results obtained show a substantial increase in mechanical properties and hence these hybrid composites can be used as an effective alternative for synthetic fibres and can be used as an alternate for different industrial application.

  14. Clinical performance of a hybrid resin composite with and without an intermediate layer of flowable resin composite: a 7-year evaluation

    DEFF Research Database (Denmark)

    van Dijken, Jan W V; Pallesen, Ulla

    2011-01-01

    The objective of this prospective clinical follow up was to evaluate the long term clinical performance of a hybrid resin composite in Class II restorations with and without intermediate layer of flowable resin composite.......The objective of this prospective clinical follow up was to evaluate the long term clinical performance of a hybrid resin composite in Class II restorations with and without intermediate layer of flowable resin composite....

  15. Transverse fracture and fiber/matrix interface characteristics of hybrid ceramic matrix composites

    Science.gov (United States)

    Haug, Stephen Berry

    Ceramic Matrix Composites (CMCs) represent an attractive class of engineering materials for use in high temperature, high wear and corrosive environments. Much effort has been made to ascertain and improve the strength and fracture characteristics of these materials. Approaches that have received a significant amount of attention include enhancing a ceramic material's mechanical properties through the use of continuous fiber reinforcement; fine, randomly dispersed discontinuous fiber (or whisker) reinforcement; and a hybrid combination of both continuous and discontinuous fibers. This dissertation addresses two important aspects of determining and improving the strength and toughness of CMCs and is comprised of three research papers that have been prepared for journal publication. The first paper, "Transverse Fracture Toughness of Unidirectional Continuous Fiber and Hybrid Ceramic Matrix Composites" provides the results of three-point chevron-notched-beam fracture toughness testing and demonstrates a significant improvement in transverse fracture toughness can be obtained through the use of hybrid fiber reinforcements. The second paper, "A Tensile Testing Method for Ceramic Matrix Composites" presents a novel approach to testing small brittle material specimens using conventional testing equipment with minimal specialized fixture components. The third paper, "Fiber/Matrix Interface Properties of Hybrid Ceramic Matrix Composites", presents a method of determining the characteristics of the fiber/matrix interface of a continuous fiber reinforced CMC and a related hybrid CMC reinforced by both continuous fibers and finely dispersed whiskers using a multiple fiber pullout technique.

  16. Composites

    Science.gov (United States)

    Taylor, John G.

    The Composites market is arguably the most challenging and profitable market for phenolic resins aside from electronics. The variety of products and processes encountered creates the challenges, and the demand for high performance in critical operations brings value. Phenolic composite materials are rendered into a wide range of components to supply a diverse and fragmented commercial base that includes customers in aerospace (Space Shuttle), aircraft (interiors and brakes), mass transit (interiors), defense (blast protection), marine, mine ducting, off-shore (ducts and grating) and infrastructure (architectural) to name a few. For example, phenolic resin is a critical adhesive in the manufacture of honeycomb sandwich panels. Various solvent and water based resins are described along with resin characteristics and the role of metal ions for enhanced thermal stability of the resin used to coat the honeycomb. Featured new developments include pultrusion of phenolic grating, success in RTM/VARTM fabricated parts, new ballistic developments for military vehicles and high char yield carbon-carbon composites along with many others. Additionally, global regional market resin volumes and sales are presented and compared with other thermosetting resin systems.

  17. Barium Titanate Film Interfaces for Hybrid Composite Energy Harvesters.

    Science.gov (United States)

    Bowland, Christopher C; Malakooti, Mohammad H; Sodano, Henry A

    2017-02-01

    Energy harvesting utilizing piezoelectric materials has become an attractive approach for converting mechanical energy into electrical power for low-power electronics. Structural composites are ideally suited for energy scavenging due to the large amount of mechanical energy they are subjected to. Here, a multifunctional composite with embedded sensing and energy harvesting is developed by integrating an active interface into carbon fiber reinforced polymer composites. By modifying the composite matrix, both rigid and flexible multifunctional composites are fabricated. Through electromechanical testing of a cantilever beam of the rigid composite, it reveals a power density of 217 pW/cc from only 1 g root-mean-square acceleration when excited at its resonant frequency of 47 Hz. Electromechanical sensor testing of the flexible multifunctional composite reveals an average voltage generation of 23.5 mV/g at its resonant frequency of 96 Hz. This research introduces a route for integrating nonstructural functionality into structural fiber composites by utilizing BaTiO3 coated woven carbon fiber fabrics with power scavenging and passive sensing capabilities.

  18. A STUDY OF THE INFLUENCE OF INTERFACIAL DAMAGE ON STRESS CONCENTRATIONS IN INTRAPLY HYBRID COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Zeng Qingdun; Lin Xuehui

    2001-01-01

    In the axial tensile failure process of intraply hybrid composites, the breakage of some fibers may lead to interfacial damage, thus directly influencing the local stress concentrations near the sites of breakage. A modified shear-lag model, in which the interfacial damage is considered, is proposed. Based on the model, the influence of interfacial shear strength on the stress concentrations and the lengths of interfacial damage zone is first studied. The present results also provide an important theoretical basis for investigating the failure mechanism and hybrid effects for such kind of composites.

  19. Tribological Potential of Hybrid Composites Based on Zinc and Aluminium Alloys Reinforced with SiC and Graphite Particles

    Directory of Open Access Journals (Sweden)

    D. Džunić

    2012-12-01

    Full Text Available The paper reviews contemporary research in the area of hybrid composites based on zinc and aluminium alloys reinforced with SiC and graphite particles. Metal matrix composites (MMCs based on ZA matrix are being increasingly applied as light-weight and wear resistant materials. Aluminium matrix composites with multiple reinforcements (hybrid AMCsare finding increased applications because of improved mechanical and tribological properties and hence are better substitutes for single reinforced composites. The results of research show that the hybrid composites possess higher hardness, higher tensile strength, better wear resistance and lower coefficient of friction when compared to pure alloys.

  20. Mechanical performance of hybrid polyester composites reinforced Cloisite 30B and kenaf fibre

    Science.gov (United States)

    Bonnia, N. N.; Surip, S. N.; Ratim, S.; Mahat, M. M.

    2012-06-01

    Hybridization of rubber toughened polyester-kenaf nanocomposite was prepared by adding various percentage of kenaf fiber with 4% Cloisite 30B in unsaturated polyester resin. Composite were prepared by adding filler to modified polyester resin subsequently cross-linked using methyl ethyl ketone peroxide and the accelerator cobalt octanoate 1%. Three per hundred rubbers (phr) of liquid natural rubber (LNR) were added in producing this composite. This composite expected to be applied in the interior of passenger cars and truck cabins. This is a quality local product from a combination of good properties polyester and high performance natural fiber, kenaf that is suitable for many applications such as in automotive sector and construction sector. The mechanical and thermal properties of composite were characterized using Durometer Shore-D hardness test, Izod impact test, Scanning electron microscopy, thermogravimetry (TGA) and differential scanning calorimetry (DSC). Result shows that addition of LNR give good properties on impact, flexural and hardness compare to without LNR composite. DSC curve shows that all composition of composites is fully cured and good in thermal properties. Addition of higher percentage of kenaf will lead the composite to elastic behavior and decrease the toughened properties of the composite. Hybrid system composite showed the flexural properties within the flexural properties of kenaf - polyester and Cloisite 30B.

  1. Silica-graphene oxide hybrid composite particles and their electroresponsive characteristics.

    Science.gov (United States)

    Zhang, Wen Ling; Choi, Hyoung Jin

    2012-05-01

    Silica-graphene oxide (Si-GO) hybrid composite particles were prepared by the hydrolysis of tetraethyl orthosilicate (TEOS) in the presence of hydrophilic GO obtained from a modified Hummers method. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images provided visible evidence of the silica nanoparticles grafted on the surface of GO, resulting in Si-GO hybrid composite particles. Energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) spectra indicated the coexistence of silica and GO in the composite particles. The Si-GO hybrid composite particles showed better thermal stability than that of GO according to thermogravimetric analysis (TGA). The electrorheological (ER) characteristics of the Si-GO hybrid composite based ER fluid were examined further by optical microscopy and a rotational rheometer in controlled shear rate mode under various electric field strengths. Shear stress curves were fitted using both conventional Bingham model and a constitutive Cho-Choi-Jhon model. The polarizability and relaxation time of the ER fluid from dielectric spectra measured using an LCR meter showed a good correlation with its ER characteristics.

  2. Mechanical behavior of polyester-based woven jute/glass hybrid composites

    Science.gov (United States)

    Ahsan, Q.; Tanju, S.

    2012-06-01

    In polymer composite fabrication system, hybridization of jute fibers with synthetic fibers is one of the techniques adopted to overcome some of the limitations (poor mechanical properties and moisture resistance) that have been identified for jute fiber reinforced composites. In the present study, the effect of hybridization on mechanical properties of jute and glass mat reinforced polyester composites has been evaluated experimentally. The composites were made of glass mat, jute mat and varying layers of jute and glass mat in the polyester matrix by applying hand lay-up technique at room temperature (250C). The values of mechanical properties obtained from tensile, flexural and interlaminar shear strength (ILSS) tests show significant improvement with the increase of glass fiber content in hybrid composites. But the positive contribution from glass mat in increasing of ILSS of composite is limited to some extent and the optimum ILSS is achieved when glass-jute incorporated in composite as 50-50 weight basis. SEM images were used to study the modes of fracture, fiber-matrix adhesion, and jute-glass layer adhesion. The fracture surfaces resulted from different tests clearly show that cracks propagate throughout the polyester matrix by tearing the jute mat and delaminating the glass mat.

  3. Polylactide-based renewable green composites from agricultural residues and their hybrids.

    Science.gov (United States)

    Nyambo, Calistor; Mohanty, Amar K; Misra, Manjusri

    2010-06-14

    Agricultural natural fibers like jute, kenaf, sisal, flax, and industrial hemp have been extensively studied in green composites. The continuous supply of biofibers in high volumes to automotive part makers has raised concerns. Because extrusion followed by injection molding drastically reduces the aspect ratio of biofibers, the mechanical performance of injection molded agricultural residue and agricultural fiber-based composites are comparable. Here, the use of inexpensive agricultural residues and their hybrids that are 8-10 times cheaper than agricultural fibers is demonstrated to be a better way of getting sustainable materials with better performance. Green renewable composites from polylactide (PLA), agricultural residues (wheat straw, corn stover, soy stalks, and their hybrids) were successfully prepared through twin-screw extrusion, followed by injection molding. The effect on mechanical properties of varying the wheat straw amount from 10 to 40 wt % in PLA-wheat straw composites was studied. Tensile moduli were compared with theoretical calculations from the rule of mixture (ROM). Combination of agricultural residues as hybrids is proved to reduce the supply chain concerns for injection molded green composites. Densities of the green composites were found to be lower than those of conventional glass fiber composites.

  4. Properties of Multifunctional Hybrid Carbon Nanotube/Carbon Fiber Polymer Matrix Composites

    Science.gov (United States)

    Cano, Roberto J.; Kang, Jin Ho; Grimsley, Brian W.; Ratcliffe, James G.; Siochi, Emilie J.

    2016-01-01

    For aircraft primary structures, carbon fiber reinforced polymer (CFRP) composites possess many advantages over conventional aluminum alloys due to their light weight, higher strength- and stiffness-to-weight ratios, and low life-cycle maintenance costs. However, the relatively low electrical and thermal conductivities of CFRP composites fail to provide structural safety in certain operational conditions such as lightning strikes. Carbon nanotubes (CNT) offer the potential to enhance the multi-functionality of composites with improved thermal and electrical conductivity. In this study, hybrid CNT/carbon fiber (CF) polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel® IM7/8852 prepreg. Resin concentrations from 1 wt% to 50 wt% were used to infuse the CNT sheets prior to composite fabrication. The interlaminar properties of the resulting hybrid composites were characterized by mode I and II fracture toughness testing. Fractographical analysis was performed to study the effect of resin concentration. In addition, multi-directional physical properties like thermal conductivity of the orthotropic hybrid polymer composite were evaluated.

  5. Algorithm of constructing hybrid effective modules for elastic isotropic composites

    Science.gov (United States)

    Svetashkov, A. A.; Miciński, J.; Kupriyanov, N. A.; Barashkov, V. N.; Lushnikov, A. V.

    2017-02-01

    The algorithm of constructing of new effective elastic characteristics of two-component composites based on the superposition of the models of Reiss and Voigt, Hashin and Strikman, as well as models of the geometric average for effective modules. These effective characteristics are inside forks Voigt and Reiss. Additionally, the calculations of the stress-strain state of composite structures with new effective characteristics give more accurate prediction than classical models do.

  6. Mechanical characterization of coir/palmyra waste fiber hybrid composites

    Science.gov (United States)

    Arumugaprabu, V.; Uthayakumar, M.; Cardona, F.; Sultan, M. T. H.

    2016-10-01

    In the present days, the utilization of palmyra fiber in automotive and aerospace applications has increased drastically due to its high strength and low weight. This research focuses on the development of composite materials using palmyra waste and coir fiber with polyester as a matrix. The mechanical properties such as tensile, flexural and impact strength of composites were investigated. Palmyra waste fiber and coir fiber with relative varying weight percentage in the ratio of 50:50, 40:60, 30:70 and 20:80 had been considered for the study. The composites were prepared by the compression moulding method. In addition, the prepared composites were subjected to moisture studies for 24 hours, 48 hours and 72 hours to know the composite resistance to water absorption. The results showed an increase in all the mechanical properties from the addition of palmyra waste. After analysing the results obtained from the study, a suitable application in the automobile and aerospace industries is suggested for the new developed composite.

  7. Processing, structure and flexural strength of CNT and carbon fibre reinforced, epoxy-matrix hybrid composite

    Indian Academy of Sciences (India)

    K Chandra Shekar; M Sai Priya; P K Subramanian; Anil Kumar; B Anjaneya Prasad; N Eswara Prasad

    2014-05-01

    Advanced materials such as continuous fibre-reinforced polymer matrix composites offer significant enhancements in variety of properties, as compared to their bulk, monolithic counterparts. These properties include primarily the tensile stress, flexural stress and fracture parameters. However, till date, there are hardly any scientific studies reported on carbon fibre (Cf) and carbon nanotube (CNT) reinforced hybrid epoxy matrix composites (unidirectional). The present work is an attempt to bring out the flexural strength properties along with a detailed investigation in the synthesis of reinforced hybrid composite. In this present study, the importance of alignment of fibre is comprehensively evaluated and reported. The results obtained are discussed in terms of material characteristics, microstructure and mode of failure under flexural (3-point bend) loading. The study reveals the material exhibiting exceptionally high strength values and declaring itself as a material with high strength to weight ratio when compared to other competing polymer matrix composites (PMCs); as a novel structural material for aeronautical and aerospace applications.

  8. Ablation Property of Ceramics/Carbon Fibers/Resin Novel Super-hybrid Composite

    Institute of Scientific and Technical Information of China (English)

    Jun QIU; Xiaoming CAO; Chong TIAN; Jinsong ZHANG

    2005-01-01

    A novel super-hybrid composite (NSHC) is prepared with three-dimension reticulated SiC ceramic (3DRC), high performance carbon fibers and modified phenolic resin (BPR) in this paper. Ablation performance of super-hybrid composite is studied. The results show that the NSHC has less linear ablation rate compared with pure BPR and CF/BPR composite, for example, its linear ablation rate is 50% of CF/BPR at the same fiber content. Mass ablation rate of the NSHC is slightly lower than that of pure BPR and CF/BPR composite because of their difference in the density. Scanning electron microscopic analysis indicates that 3DRC can increase anti-erosion capacity of materials because its special reticulated structure can control the deformation of materials and strengthen the stability of integral structure.

  9. Effect of fiber loading on flexural strength of hybrid sisal/hemp-HDPE composites

    Science.gov (United States)

    Aggarwal, Lakshya; Sinha, Shishir; Gupta, V. K.

    2015-05-01

    The continuing demand for sustainable materials and increasing environmental concerns have led to intense research in the field of natural fiber reinforced composites. Natural fibers are favored over synthetic fibers as reinforcement due to positive environmental benefits such as raw material utilization at source and easy disposable of the biodegradable fiber. In the present work, we have investigated flexural behavior of hybrid natural fiber reinforced HDPE composites. The matrix comprises of 50-50 ratio of virgin and recycled HDPE and the content of fibers (sisal and hemp) in the composite is varied from 10 to 30%. The natural fibers were mercerized with NaOH solution and chemically treated with maleic anhydride. The flexural specimens were prepared by injection moulding process and the testing was conducted in accordance to ASTM D790 standards. It is revealed that the flexural strength of the hybrid composite increases with the increase in fibers content when compared to specimen containing 100% HDPE.

  10. A six-year prospective randomized study of a nano-hybrid and a conventional hybrid resin composite in Class II restorations

    DEFF Research Database (Denmark)

    van Dijken, Jan W V; Pallesen, Ulla

    2013-01-01

    The objective of this 6 year prospective randomized equivalence trial was to evaluate the long-term clinical performance of a new nano-hybrid resin composite (RC) in Class II restorations in an intraindividual comparison with its well-established conventional hybrid RC predecessor....

  11. Effect of Light Direction on the Microleakage of Micro Filled and Hybrid Resin Composites

    Directory of Open Access Journals (Sweden)

    A Davari

    2010-11-01

    Full Text Available Introduction: One of the most important factors affecting the marginal seal of composite restorations is polymerization shrinkage. The aim of this study was to evaluate the micro leakage of two resin composites cured with two light directions. Methods: In this experimental study, forty similar class III preparations were prepared in 40 human anterior teeth. The teeth were randomly divided in two groups according to the resin composite used for filling the cavities (Microfilled composite: Heliomolar or hybrid composite: Spectrum. Etch group was further divided in two subgroups according to the light direction buccal and lingual. All the cavities were filled with the composites and cured for 40 seconds. The teeth were then thermocycled for 500 cycles between 5-55°c and covered with nail polish except for 1mm around cavity margins and immersed in 1% methylene blue for 12 hours. The teeth were sectioned and the dye penetration scores were recorded using stereo microscope. Data was analyzed using non parametric Mann Whitney test. Results: No significant difference was observed between the composite resins (p>0.05 or the light directions used for curing the composite resins (p>0.05. Conclusion: Directions of the light does not have any effect on the micro leakage of hybrid or micro filled composites in class III cavities.

  12. Aptamer-gelatin composite for a trigger release system mediated by oligonucleotide hybridization.

    Science.gov (United States)

    Soontornworajit, Boonchoy; Srakaew, Prangkamol; Naramitpanich, Pajaree

    2014-01-01

    Nucleic acid aptamers not only specifically bind to their target proteins with high affinity but also form intermolecular hybridization with their complementary oligonucleotides (CO). The hybridization can interrupt aptamer/protein interaction due to the changes of aptamer secondary structure which rely on hybridization length and base-pairing positions. Herein we aim to use this unique property of the aptamers, when combined with gelatin to develop a novel composite with desirable protein release profiles. Platelet-derived growth factor-BB (PDGF-BB) and its aptamer were used as target molecules. Prior to performing the release study, the effects of CO on aptamer-protein interaction were observed by surface plasmon resonance (SPR). The SPR sensorgram indicated that the aptamer dissociated from the bounded proteins when it hybridized with the CO. The aptamer was then immobilized onto streptavidin coated polystyrene particles via biotin/streptavidin interaction. Then, PDGF-BB and aptamer functionalized particles were mixed with gelatin solution and cast as small pieces of composite. The success of the composite preparation was confirmed by flow cytometry and microscopy. PDGF-BB release at several time points was quantified by ELISA. The results showed that the aptamer-gelatin composite could slow the release rate of the proteins from the composite due to strong binding of proteins and aptamers. Once the CO was added to the system, the release rate was significantly enhanced because the aptamer hybridized with the CO and lost its active secondary structure. Therefore, the proteins were triggered to release out from the composite. This work suggests a promising strategy for controlling the release of bioactive molecules in medical treatments.

  13. Synthesis and characterization of hybrid silica/PMMA nanoparticles and their use as filler in dental composites

    Energy Technology Data Exchange (ETDEWEB)

    Canché-Escamilla, G., E-mail: gcanche@cicy.mx [Unidad de Materiales, Centro de Investigación Científica de Yucatán A.C. Calle 43 No. 130 Col. Chuburná de Hidalgo, Mérida, Yucatán 97200 (Mexico); Duarte-Aranda, S. [Unidad de Materiales, Centro de Investigación Científica de Yucatán A.C. Calle 43 No. 130 Col. Chuburná de Hidalgo, Mérida, Yucatán 97200 (Mexico); Toledano, M. [Facultad de Odontología, Universidad de Granada, Campus Universitario de Cartuja s/n, Granada 18071 (Spain)

    2014-09-01

    The effect of hybrid silica/poly(methylmethacrylate) (PMMA) nanoparticles on the properties of composites for dental restoration was evaluated. Hybrid nanoparticles with silica as core and PMMA as shell were obtained by a seeded emulsion polymerization process. Fourier transform infrared spectrum of the hybrid nanoparticles shows an intense peak at 1730 cm{sup −1}, corresponding to carbonyl groups (C=O) of the ester. The thermal stability of the hybrid particles decreases with increasing amounts of PMMA and the residual mass at 700 °C corresponds to the silica content in the hybrid particles. Composites were obtained by dispersing nanoparticles (silica or hybrid), as fillers, in a resin—bis glycidyl dimethacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) (40%/60% (w/w)). The paste was then placed in a mold and polymerized under light irradiation. During the preparation of the composites, with the hybrid nanoparticles, the monomers swell the PMMA shell and after photo-curing, a semi-interpenetrating network (semi-IPN) is obtained around the silica core. The properties of the composites, obtained using the hybrid nanoparticles, depend on the filler content and the amount of PMMA in the semi-IPN matrix. For composites with similar inorganic filler contents, the composites with low amounts of PMMA shell had higher modulus than those in which silica was used as the filler. - Highlights: • Hybrid nanoparticles silica/PMMA were used as fillers in dental composites. • The properties of the hybrid nanoparticle depend on the silica/PMMA content ratio. • A higher content of inorganic filler was obtained using hybrid nanoparticle. • Composites with higher modulus were obtained using hybrid nanoparticles. • A semi-IPN matrix between the PMMA shell and the resin is obtained.

  14. Optimal design of damping layers in SMA/GFRP laminated hybrid composites

    Science.gov (United States)

    Haghdoust, P.; Cinquemani, S.; Lo Conte, A.; Lecis, N.

    2017-10-01

    This work describes the optimization of the shape profiles for shape memory alloys (SMA) sheets in hybrid layered composite structures, i.e. slender beams or thinner plates, designed for the passive attenuation of flexural vibrations. The paper starts with the description of the material and architecture of the investigated hybrid layered composite. An analytical method, for evaluating the energy dissipation inside a vibrating cantilever beam is developed. The analytical solution is then followed by a shape profile optimization of the inserts, using a genetic algorithm to minimize the SMA material layer usage, while maintaining target level of structural damping. Delamination problem at SMA/glass fiber reinforced polymer interface is discussed. At the end, the proposed methodology has been applied to study the hybridization of a wind turbine layered structure blade with SMA material, in order to increase its passive damping.

  15. Kenaf-glass fiber reinforced unsaturated polyester hybrid composites: Tensile properties

    Science.gov (United States)

    Zhafer, S. F.; Rozyanty, A. R.; Shahnaz, S. B. S.; Musa, L.; Zuliahani, A.

    2016-07-01

    The use of natural fibers in composite is rising in recent years due their lightweight, non-abrasive, combustible, non-toxic, low cost and biodegradable properties. However, in comparison with synthetic fibers, the mechanical properties of natural fibers are lower. Therefore, the inclusion of synthetic fibers could improve the mechanical performance of natural fiber based composites. In this study, kenaf bast fiber and glass fiber at different weight percentage loading were used as reinforcement to produce hybrid composites. Unsaturated polyester (UP) resin was used as matrix and hand lay-up process was performed to apply the UP resin on the hybrid kenaf bast/glass fiber composite. Effect of different fiber loading on tensile strength, tensile modulus and elongation at break of the hybrid composite was studied. It has been found that the highest value of tensile strength and modulus was achieved at 10 wt.% kenaf/10 wt.% glass fiber loading. It was concluded that addition of glass fiber has improved the tensile properties of kenaf bast fiber based UP composites.

  16. The Mechanical Properties and Microstructure Characters of Hybrid Composite Geopolymers-Pineapple Fiber Leaves (PFL)

    Science.gov (United States)

    Amalia, N.; Hidayatullah, S.; Nurfadilla; Subaer

    2017-03-01

    The objective of this research is to study the influence of organic fibers on the mechanical properties and microstructure characters of hybrid composite geopolymers-pineapple fibers (PFL). Geopolymers were synthesized by using alkali activated of class C-fly ash added manually with short pineapple fiber leaves (PFL) and then cured at 60°C for 1 hour. The resulting composites were stored in open air for 28 days prior to mechanical and microstructure characterizations. The samples were subjected to compressive and flexural strength measurements, heat resistance as well as acid attack (1M H2SO4 solution). The microstructure of the composites were examined by using Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS). The measurement showed that the addition of pineapple fibers was able to improve the compressive and flexural strength of geopolymers. The resulting hybrid composites were able to resist fire to a maximum temperature of 1500°C. SEM examination showed the presence of good bond between geopolymer matrix and pineapple fibers. It was also found that there were no chemical constituents of geopolymers leached out during acid liquid treatment. It is concluded that hybrid composite geopolymers-pineapple fibers are potential composites for wide range applications.

  17. Effects of fibre orientation on mechanical properties of hybrid bamboo/glass fibre polymer composites

    Indian Academy of Sciences (India)

    B Stanly Jones Retnam; M Sivapragash; P Pradeep

    2014-08-01

    The usage of natural fibre as reinforcement in polymer composites have widely increased because of its enhanced properties. The usage of plant fibre cannot alone satisfy all the needs of the composites. Hence, introduction of hybrid plays a vital role in enhancing the mechanical properties of the FRP composites. Fibre orientation contributes significant role in improving the mechanical properties of the FRP composites. In this proposal, hybrid bamboo/glass fibre woven in different orientations such as 0°/90° and ± 45° was used and its effect on mechanical properties were studied. Composites containing hybrid fibres found to possess better mechanical properties, when compared to pure bamboo. In order to justify this, the following mechanical properties such as tensile, flexural, impact and hardness were investigated. SEM analysis shows the bonding between the matrix and reinforcement. All the above test results indicate that the introduction of natural bamboo fibre in glass reduces the overall cost of the composites with no compromise in strength and also attracted several studies covering green technologies.

  18. Effect of probiotic preparation for chemical composition of meat cocks different combinations of hybrid chicks

    Directory of Open Access Journals (Sweden)

    Peter Haščík

    2011-01-01

    Full Text Available In the experiment were verified the application of probiotic preparation through a water supply for feeding of cock’s hybrids Ross 308, Hubbard JV and Cobb 500 in the chemical composition of the most valuable parts of the carcass. Probiotic was based on the strain Lactobacillus fermentum with containing of 1.109 cfu.g−1 and potentially components of maltodextrin and oligofructose in 1% concentration. Length of feeding period was 42 days. Cocks were fed an ad libitum with the same starter mixture HYD-01 to 21th day and from 22nd to 42nd day of feeding with mixture HYD-02 in powdery form. The average of protein content of breast muscle was highest in Hubbard JV hybrid (23.93 g.100 g−1, lower in Cobb 500 hybrid (23.90 g.100 g−1 and lowest in Ross 308 hybrid (23.73 g.100 g−1, without significant differences (P ≥ 0.05 between hybrids and hybrids groups. Effect of probiotics had increased the protein content (P ≥ 0.05 in breast muscle of Ross 308 and Cobb 500 cocks and at the Hubbard JV only lower doses application during the feeding. The average of fat content in 100 g of breast muscle was lowest in Cobb 500 hybrid (1.09 g, higher in Hubbard JV hybrid (1.28 g and highest in Ross 308 hybrid (1.35 g. Effect of probiotic to reduce fat content in breast muscle of cocks was at Ross 308 hybrid (1.33 and 1.23 g.100 g−1, Cobb 500 hybrid (0.98 and 1.02 g.100 g−1 and in second experimental group at Hubbard JV hybrid (1.03 g.100 g−1 statistically significant (P ≥ 0.05 in compared with control group, but significantly (P ≤ 0.05 between hybrids Cobb 500 and Hubbard JV in the first test groups. The average of energy value in 100 g of breast muscle was highest in Hubbard JV hybrid (449.24 kJ, lower in Ross 308 hybrid (448.40 kJ and lowest in Cobb 500 hybrid (441.45 kJ, without significant differences (P ≥ 0.05 between hybrids and hybrids groups. The average of protein content of the femur was highest in Ross 308 hybrid (18.56 g.100

  19. Enhanced dielectric performance in polymer composite films with carbon nanotube-reduced graphene oxide hybrid filler.

    Science.gov (United States)

    Kim, Jin-Young; Kim, TaeYoung; Suk, Ji Won; Chou, Harry; Jang, Ji-Hoon; Lee, Jong Ho; Kholmanov, Iskandar N; Akinwande, Deji; Ruoff, Rodney S

    2014-08-27

    The electrical conductivity and the specific surface area of conductive fillers in conductor-insulator composite films can drastically improve the dielectric performance of those films through changing their polarization density by interfacial polarization. We have made a polymer composite film with a hybrid conductive filler material made of carbon nanotubes grown onto reduced graphene oxide platelets (rG-O/CNT). We report the effect of the rG-O/CNT hybrid filler on the dielectric performance of the composite film. The composite film had a dielectric constant of 32 with a dielectric loss of 0.051 at 0.062 wt% rG-O/CNT filler and 100 Hz, while the neat polymer film gave a dielectric constant of 15 with a dielectric loss of 0.036. This is attributed to the increased electrical conductivity and specific surface area of the rG-O/CNT hybrid filler, which results in an increase in interfacial polarization density between the hybrid filler and the polymer.

  20. Probing Structure and Composition of Nickel/Titanium Carbide Hybrid Interfaces at the Atomic Scale (Preprint)

    Science.gov (United States)

    2010-01-01

    The transition in structure and composition across the titanium carbide /nickel hybrid interface has been determined at near atomic resolution by...coupling high-resolution transmission electron microscopy with three-dimensional atom probe tomography. The titanium carbide phase adopts a rocksalt-type

  1. Degradation of shear stiffness of Nomex honeycomb sandwich panel in laser irradiation

    Science.gov (United States)

    Wang, Jiawei; Jiang, Houman; Wu, Lixiong; Zhu, Yongxiang; Wei, Chenghua; Ma, Zhiliang; Wang, Lijun

    2017-05-01

    Based on the overhanging beam three-point bending method, the experimental system was set up to measure the variety of shear stiffness of Nomex honeycomb sandwich panel in laser irradiation. The shear stiffness of the specimens under different laser power density was measured. The result shows that the thermal effect during the laser irradiation leads to the degradation of mechanical properties of Nomex honeycomb sandwich panel. High temperature rise rate in the specimen is another main reason for the shear stiffness degeneration. This research provides a reference for the degradation of mechanical properties of composite materials in laser irradiation and proposes a new method for the study of laser interaction with matter.

  2. A Maximum Entropy Approach to Assess Debonding in Honeycomb aluminum Plates

    Directory of Open Access Journals (Sweden)

    Viviana Meruane

    2014-05-01

    Full Text Available Honeycomb sandwich structures are used in a wide variety of applications. Nevertheless, due to manufacturing defects or impact loads, these structures can be subject to imperfect bonding or debonding between the skin and the honeycomb core. The presence of debonding reduces the bending stiffness of the composite panel, which causes detectable changes in its vibration characteristics. This article presents a new supervised learning algorithm to identify debonded regions in aluminum honeycomb panels. The algorithm uses a linear approximation method handled by a statistical inference model based on the maximum-entropy principle. The merits of this new approach are twofold: training is avoided and data is processed in a period of time that is comparable to the one of neural networks. The honeycomb panels are modeled with finite elements using a simplified three-layer shell model. The adhesive layer between the skin and core is modeled using linear springs, the rigidities of which are reduced in debonded sectors. The algorithm is validated using experimental data of an aluminum honeycomb panel under different damage scenarios.

  3. Mould design and manufacturing considerations of honeycomb biocomposites with transverse fibre direction for aerospace application

    Science.gov (United States)

    Manan, N. H.; Majid, D. L.; Romli, F. I.

    2016-10-01

    Sandwich structures with honeycomb core are known to significantly improve stiffness at lower weight and possess high flexural rigidity. They have found wide applications in aerospace as part of the primary structures, as well as the interior paneling and floors. High performance aluminum and aramid are the typical materials used for the purpose of honeycomb core whereas in other industries, materials such as fibre glass, carbon fibre, Nomex and also Kevlar reinforced with polymer are used. Recently, growing interest in developing composite structures with natural fibre reinforcement has also spurred research in natural fibre honeycomb material. The majority of the researches done, however, have generally emphasized on the usage of random chopped fibre and only a few are reported on development of honeycomb structure using unidirectional fibre as the reinforcement. This is mainly due to its processing difficulties, which often involve several stages to account for the arrangement of fibres and curing. Since the use of unidirectional fibre supports greater strength compared to random chopped fibre, a single-stage process in conjunction with vacuum infusion is suggested with a mould design that supports fibre arrangement in the direction of honeycomb loading.

  4. Glassy Carbon Coating Deposited on Hybrid Structure of Composite Materials

    Directory of Open Access Journals (Sweden)

    Posmyk A.

    2016-06-01

    Full Text Available This paper presents a method of production metal matrix composites with aluminum oxide foam covered by glassy carbon layer used as reinforcement. The glassy carbon coating was formed for decreasing of friction coefficient and reducing the wear. In first step of technology liquid glassy carbon precursor is on ceramic foam deposited, subsequently cured and carbonated at elevated temperature. In this way ceramic foam is covered with glassy carbon coating with thickness of 2-8 μm. It provides desirable amount of glassy carbon in the structure of the material. In the next step, porous spheres with carbon coating are infiltrated by liquid matrix of Al-Cu-Mg alloy. Thereby, equable distribution of glassy carbon in composite volume is achieved. Moreover, typical problems for composites reinforced by particles like sedimentation, agglomeration and clustering of particles are avoided. Tribological characteristics during friction in air versus cast iron as a counterpart were made. Produced composites with glassy carbon layer are characterised by friction coefficient between 0.08-0.20, thus meeting the typical conditions for solid lubricants.

  5. Tensile stress-strain behavior of hybrid composite laminates

    Science.gov (United States)

    Kennedy, J. M.

    1983-01-01

    A study was made of the stress-strain response of several hybrid laminates, and the damage was correlated with nonlinear stress-strain response and ultimate strength. The fibers used in the laminates were graphite, S-glass, and Kevlar. Some laminates with graphite fibers had perforated Mylar film between plies, which lowered the interlaminar bond strength. The laminate configurations were chosen to be like those of buffer strips in large panels and fracture coupons. Longitudinal and transverse specimens were loaded in tension to failure. Some specimens were radiographed to reveal damage due to edge effects. Stress-strain response is discussed in terms of damage shown by the radiographs. Ultimate strengths are compared with simple failure criteria, one of which account for damage.

  6. Fabrication and development of several heat pipe honeycomb sandwich panel concepts

    Science.gov (United States)

    Tanzer, H. J.

    1982-06-01

    The feasibility of fabricating and processing liquid metal heat pipes in a low mass honeycomb sandwich panel configuration for application on the NASA Langley airframe-integrated Scramjet engine was investigated. A variety of honeycomb panel facesheet and core-ribbon wick concepts was evaluated within constraints dictated by existing manufacturing technology and equipment. The chosen design consists of an all-stainless steel structure, sintered screen facesheets, and two types of core-ribbon; a diffusion bonded wire mesh and a foil-screen composite. Cleaning, fluid charging, processing, and process port sealing techniques were established. The liquid metals potassium, sodium and cesium were used as working fluids. Eleven honeycomb panels 15.24 cm X 15.24 cm X 2.94 cm were delivered to NASA Langley for extensive performance testing and evaluation; nine panels were processed as heat pipes, and two panels were left unprocessed.

  7. Fabrication and development of several heat pipe honeycomb sandwich panel concepts. [airframe integrated scramjet engine

    Science.gov (United States)

    Tanzer, H. J.

    1982-01-01

    The feasibility of fabricating and processing liquid metal heat pipes in a low mass honeycomb sandwich panel configuration for application on the NASA Langley airframe-integrated Scramjet engine was investigated. A variety of honeycomb panel facesheet and core-ribbon wick concepts was evaluated within constraints dictated by existing manufacturing technology and equipment. The chosen design consists of an all-stainless steel structure, sintered screen facesheets, and two types of core-ribbon; a diffusion bonded wire mesh and a foil-screen composite. Cleaning, fluid charging, processing, and process port sealing techniques were established. The liquid metals potassium, sodium and cesium were used as working fluids. Eleven honeycomb panels 15.24 cm X 15.24 cm X 2.94 cm were delivered to NASA Langley for extensive performance testing and evaluation; nine panels were processed as heat pipes, and two panels were left unprocessed.

  8. Effects of different saliva pH on hybrid composite resin surface roughness

    Directory of Open Access Journals (Sweden)

    Nirawati Pribadi

    2011-06-01

    Full Text Available Background: Currently, hybrid composite resin is the mostly used filling material to restore esthetic and function. During function, this material is in contact with various pH from food consumption, which is acidic and alkali which may effect the physical properties of composite resin, including surface roughness. Purpose: The research was conducted to determine the effect of pH in saliva on surface roughness of hybrid composite resin. Methods: This research used artificial saliva and composite resin samples divided into 3 groups based on different pH of immersion (pH 4, pH 7 and pH 10 for 30 days. Results: There were significant differences (p > 0.05 among those three treatment groups of hybrid composites soaked in artificial saliva with different pH for 30 days. And, with LSD test it is also known that there were significant differences between the artificial saliva with pH 4 and pH 7, whereas there was no significant difference between pH 4 and pH 10 and between pH 7 and pH 10. Conclusion: It can concluded that the changes of salivary pH affect the surface roughness of the hybrid composite resin. Acidic pH has increase the surface roughness of hybrid composite resin, whereas alkaline pH has no effects on the surface roughness of hybrid composite resin.Latar belakang: Saat ini tumpatan komposit merupakan bahan tumpatan yang paling sering digunakan untuk memperbaiki estetik dan fungsi. Dalam rongga mulut, bahan ini kontak dengan berbagai macam pH dari konsumsi makanan, baik asam maupun basa yang dapat mempengaruhi perubahan sifat fisik resin komposit, diantaranya yaitu kekasaran permukaan. Tujuan: Penelitian ini dilakukan untuk mengetahui tentang efek pH saliva terhadap kekasaran permukaan tumpatan resin komposit hybrid. Metode: Penelitian ini menggunakan saliva buatan yang dibagi dalam 3 kelompok sampel yaitu masing-masing dengan perendaman pH yang berbeda (pH 4, pH 7 dan pH 10selama 30 hari. Hasil: Terdapat perbedaan yang bermakna (p > 0

  9. Evaluation on mechanical properties of woven aloevera and sisal fibre hybrid reinforced epoxy composites

    Indian Academy of Sciences (India)

    A Shadrach Jeya Sekaran; K Palani Kumar; K Pitchandi

    2015-09-01

    Natural fibres as reinforcement in polymer composite for making low-cost materials are growing day by day. Researcher’s main attention is to apply appropriate technology to utilize these natural fibres as effectively and economically as possible to produce good quality fibre-reinforced polymer composites for various engineering applications. In this research, the experiments of tensile, flexural and impact tests were carried out for woven aloevera and sisal fibre hybrid-reinforced epoxy composites. The hand layup method of fabrication was employed in preparing the composites. The surface morphology of the composites was examined through scanning electron microscope. Due to the low-density and high-specific properties of sisal fibre composites, it offer cost savings when compared with synthetic fibres. Hence it has very good implications in the automotive and transportation industry.

  10. Plant genetics affects arthropod community richness and composition: evidence from a synthetic eucalypt hybrid population.

    Science.gov (United States)

    Dungey, H S; Potts, B M; Whitham, T G; Li, H F

    2000-12-01

    To examine how genetic variation in a plant population affects arthropod community richness and composition, we quantified the arthropod communities on a synthetic population of Eucalyptus amygdalina, E. risdonii, and their F1 and advanced-generation hybrids. Five major patterns emerged. First, the pure species and hybrid populations supported significantly different communities. Second, species richness was significantly greatest on hybrids (F1 > F2 > E. amygdalina > E. risdonii). These results are similar to those from a wild population of the same species and represent the first case in which both synthetic and wild population studies confirm a genetic component to community structure. Hybrids also acted as centers of biodiversity by accumulating both the common and specialist taxa of both parental species (100% in the wild and 80% in the synthetic population). Third, species richness was significantly greater on F1s than the single F2 family, suggesting that the increased insect abundance on hybrids may not be caused by the breakup of coadapted gene complexes. Fourth, specialist arthropod taxa were most likely to show a dominance response to F1 hybrids, whereas generalist taxa exhibited a susceptible response. Fifth, in an analysis of 31 leaf terpenoids that are thought to play a role in plant defense, hybrids were generally intermediate to the parental chemotypes. Within the single F2 family, we found significant associations between the communities of individual trees and five individual oil components, including oil yield, demonstrating that there is a genetic effect on plant defensive chemistry that, in turn, may affect community structure. These studies argue that hybridization has important community-level consequences and that the genetic variation present in hybrid zones can be used to explore the genetic-based mechanisms that structure communities.

  11. Polyetheretherketone Hybrid Composites with Bioactive Nanohydroxyapatite and Multiwalled Carbon Nanotube Fillers

    Directory of Open Access Journals (Sweden)

    Chen Liu

    2016-12-01

    Full Text Available Polyetheretherketone (PEEK hybrid composites reinforced with inorganic nanohydroxyapatite (nHA and multiwalled carbon nanotube (MWNT were prepared by melt-compounding and injection molding processes. The additions of nHA and MWNT to PEEK were aimed to increase its elastic modulus, tensile strength, and biocompatibility, rendering the hybrids suitable for load-bearing implant applications. The structural behavior, mechanical property, wettability, osteoblastic cell adhesion, proliferation, differentiation, and mineralization of the PEEK/nHA-MWNT hybrids were studied. X-ray diffraction and SEM observation showed that both nHA and MWNT fillers are incorporated into the polymer matrix of PEEK-based hybrids. Tensile tests indicated that the elastic modulus of PEEK can be increased from 3.87 to 7.13 GPa by adding 15 vol % nHA and 1.88 vol % MWNT fillers. The tensile strength and elongation at break of the PEEK/(15% nHA-(1.88% MWNT hybrid were 64.48 MPa and 1.74%, respectively. Thus the tensile properties of this hybrid were superior to those of human cortical bones. Water contact angle measurements revealed that the PEEK/(15% nHA-(1.88% MWNT hybrid is hydrophilic due to the presence of nHA. Accordingly, hydrophilic PEEK/(15% nHA-(1.88% MWNT hybrid promoted the adhesion, proliferation, differentiation, and mineralization of murine MC3T3-E1 osteoblasts on its surface effectively on the basis of cell culture, fluorescence microscopy, MTT assay, WST-1 assay, alkaline phosphatase activity, and Alizarin red staining tests. Thus the PEEK/(15% nHA-(1.88% MWNT hybrid has the potential to be used for fabricating load-bearing bone implants.

  12. Analysis of Surface Integrity in Drilling Metal Matrix and Hybrid Metal Matrix Composites

    Institute of Scientific and Technical Information of China (English)

    T. Rajmohan; K. Palanikumar; J. Paulo Davim

    2012-01-01

    Hybrid metal matrix composites consist of at least three constituents-a metal or an alloy matrix and two reinforcements in various forms, bonded together at the atomic level in the composite. Despite their higher specific properties of strength and stiffness, the non homogeneous and anisotropic nature combined with the abrasive reinforcements render their machining difficult. In this paper, the surface integrity of machining in drilling hybrid composites has been discussed. Drilling tests are carried out at different spindle speed, feed rates, and different drill tool materials to investigate the effect of the various cutting parameters on the surface quality and the extent of the deformation of drilled surface due to drilling. Materials used for the present investigation are A1356/IOSIC (wt%) metal matrix and A1356/10SiC-3mica (wt%) hybrid composites. The composites are fabricated using stir casting route. The drilling tests are conducted on vertical computer numeric control (CNC) machining center using carbide, coated carbide and polycrystalline diamond (PCD) drills. The surface roughness decreases with increasing spindle speed and increases with increasing feed rate. The machined surface is analyzed by scanning electron microscopy (SEM). SEM images of the machined surfaces indicate the presence of grooves and pits. Microhardness depth profiles indicate that the subsurface damage is limited to the top of 100-250 μm.

  13. A Study of Hybrid Composite Hydroxyapatite (HA-Geopolymers as a Material for Biomedical Application

    Directory of Open Access Journals (Sweden)

    Saleha

    2017-01-01

    Full Text Available The main purpose of this research is to study the physical properties and microstructure characters of hybrid composites HA-geopolymers as a material for biomedical application. Hybrid composite HA–geopolymers were produced through alkaline activation method of metakaolin as a matrix and HA as the filler. HA was synthesized from eggshell particles by using a precipitation method. The addition of HA in metakaolin paste was varied from 0.5%, 1.0%, 1.5%, and 2.0% relative the weight of metakaolin. FTIR was used to examine the absorption bands the composites. X-ray diffraction (XRD was used to study the crystal structure of the starting and the resulting materials. Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS was used to investigate the surface morphology of the composites. The thermal properties of the samples was examined by means of Differential Scanning Calorimetry (DSC. Capacitance measurement was conducted to investigate the bioactive properties of HA. The study results suggest that hybrid composite HA-geopolymers has a potential to be applied as a biomedical such as biosensor material.

  14. Three-dimensional hybrid-stress finite element analysis of composite laminates with cracks and cutouts

    Science.gov (United States)

    Wang, S. S.

    1985-01-01

    A three-dimensional hybrid-stress finite element analysis of composite laminates containing cutouts and cracks is presented. Fully three-dimensional, hexahedral isoparametric elements of the hybrid-stress model are formulated on the basis of the Hellinger-Reissner variational principle. Traction-free edges, cutouts, and crack surfaces are modeled by imposition of exact traction boundary conditions along element surfaces. Special boundary and surface elements are constructed by introducing proper constraints on assumed stress functions. The Lagrangian multiplier technique is used to enforce ply-interface continuity conditions in hybrid bimaterial composite elements for modeling the interface region in a composite laminate. Two examples are given to illustrate the capability of the present method of approach: (1) the well-known delamination problem in an angle-ply laminate, and (2) the important problem of a composite laminate containing a circular hole. Results are presented in detail for each case. Implications of interlaminar and intralaminar crack initiation, growth and fracture in composites containing cracks and cutouts are discussed.

  15. A Review on Potentiality of Nano Filler/Natural Fiber Filled Polymer Hybrid Composites

    Directory of Open Access Journals (Sweden)

    Naheed Saba

    2014-08-01

    Full Text Available The increasing demand for greener and biodegradable materials leading to the satisfaction of society requires a compelling towards the advancement of nano-materials science. The polymeric matrix materials with suitable and proper filler, better filler/matrix interaction together with advanced and new methods or approaches are able to develop polymeric composites which shows great prospective applications in constructions and buildings, automotive, aerospace and packaging industries. The biodegradability of the natural fibers is considered as the most important and interesting aspects of their utilization in polymeric materials. Nanocomposite shows considerable applications in different fields because of larger surface area, and greater aspect ratio, with fascinating properties. Being environmentally friendly, applications of nanocomposites offer new technology and business opportunities for several sectors, such as aerospace, automotive, electronics, and biotechnology industries. Hybrid bio-based composites that exploit the synergy between natural fibers in a nano-reinforced bio-based polymer can lead to improved properties along with maintaining environmental appeal. This review article intended to present information about diverse classes of natural fibers, nanofiller, cellulosic fiber based composite, nanocomposite, and natural fiber/nanofiller-based hybrid composite with specific concern to their applications. It will also provide summary of the emerging new aspects of nanotechnology for development of hybrid composites for the sustainable and greener environment.

  16. Fabrication and evaluation of mechanical properties of alkaline treated sisal/hemp fiber reinforced hybrid composite

    Science.gov (United States)

    Venkatesha Gupta, N. S.; Akash; Sreenivasa Rao, K. V.; kumar, D. S. Arun

    2016-09-01

    Fiber reinforced polymer composite have acquired a dominant place in variety of applications because of higher specific strength and modulus, the plant based natural fiber are partially replacing currently used synthetic fiber as reinforcement for polymer composites. In this research work going to develop a new material which posses a strength to weight ratio that for exceed any of the present material. The hybrid composite sisal/hemp reinforced with epoxy matrix has been developed by compression moulding technique according to ASTM standards. Sodium hydroxide (NAOH) was used as alkali for treating the fibers. The amount of reinforcement was varied from 10% to 50% in steps of 10%. Prepared specimens were examined for mechanical properties such as tensile strength, flexural strength, and hardness. Hybrid composite with 40wt% sisal/hemp fiber were found to posses higher strength (tensile strength = 53.13Mpa and flexural strength = 82.07Mpa) among the fabricated hybrid composite specimens. Hardness value increases with increasing the fiber volume. Morphological examinations are carried out to analyze the interfacial characteristics, internal structure and fractured surfaces by using scanning electron microscope.

  17. Aerogel Hybrid Composite Materials: Designs and Testing for Multifunctional Applications

    Science.gov (United States)

    Williams, Martha K.; Fesmire, James E.

    2016-01-01

    This webinar will introduce the broad spectrum of aerogel composites and their diverse performance properties such as reduced heat transfer to energy storage, and expands specifically on the aerogel/fiber laminate systems and testing methodologies. The multi-functional laminate composite system, AeroFiber, and its construction is designed by varying the type of fiber (e.g. polyester, carbon, Kevlar®, Spectra® or Innegral(TradeMark) and combinations thereof), the aerogel panel type and thickness, and overall layup configuration. The combination and design of materials may be customized and tailored to achieve a range of desired properties in the resulting laminate system. Multi-functional properties include structural strength, impact resistance, reduction in heat transfer, increased fire resistance, mechanical energy absorption, and acoustic energy dampening. Applications include aerospace, aircraft, automotive, boating, building and construction, lightweight portable structures, liquefied natural gas, cryogenics, transportation and energy, sporting equipment, and military protective gear industries.

  18. Effect of aggressive beverage on the color stability of different nano-hybrid resin based composite

    Directory of Open Access Journals (Sweden)

    Hicham Oday Nuaimi

    2014-01-01

    Full Text Available Background: The purpose of this study was to evaluate the color stability of different types of nano-hybrid resin based composite restorative materials upon exposure to aggressive staining solutions (coffee and tea over time. The color of all specimens before and after storage in the solutions were measured by a spectrophotometer based on CIE Lab system that is recommended by the American Dental Association and the color differences thereby is calculated. Materials and Methods: The color differences of three nano-hybrid composites after immersion for 30 days in tea and coffee as aggressive beverage solutions. Results: Within the limitations of the study, Venus Diamond was found the most color stable in tea, while Ceram X was shown the most color stable in coffee. There were statistically significant differences between Filtek 350 XT in tea and coffee storage (P 0.005. Conclusion: Staining solutions are significant factors that affect color stability of composite resins.

  19. In-service performance and behavior characterization of the hybrid composite bridge system - a case study

    CERN Document Server

    Civitillo, John M; Gheitasi, Amir; Saliba, Mark; Kassner, Bernard L

    2014-01-01

    The Hybrid Composite Beam (HCB) system is an innovative structural technology that has been recently used in bridge construction within the U.S. transportation network. In this system, the superstructure consists of a conventional reinforced concrete deck supported by Hybrid Composite Beams. Each beam is comprised of a glassfiber reinforced polymer (FRP) box shell containing a tied parabolic concrete arch. Inclined stirrups provide shear integrity and enforce composite action between the HCBs and the concrete deck. This paper focuses on evaluating the in-service performance of a newly constructed HCB bridge superstructure located on Route 205 in Colonial Beach, Virginia. A live load test was conducted using tandem axle dump trucks under both quasi-static and dynamic conditions. Results obtained from the experimental investigation were used to determine three key behavior characteristics. Dynamic amplification and lateral load distribution were found to be reasonable in comparison to the assumed design values....

  20. Property Relationship in Organosilanes and Nanotubes Filled Polypropylene Hybrid Composites

    Directory of Open Access Journals (Sweden)

    Alejandra J. Monsiváis-Barrón

    2014-10-01

    Full Text Available Polypropylene composites with different filler contents were prepared by creating a masterbatch containing 3 wt%. filler. A variety of silanol groups were used to synthetized three compounds in different media trough a sol-gel process with acetic acid, formic acid and ammonium hydroxide as catalysts. Besides, four different nanotubular fillers were also used to analyze their behavior and compare it with the effect caused by the silanol groups. These tubular structures comprise: unmodified halloysite, carbon nanotubes and functionalized halloysite and carbon nanotubes. Morphological characterization in SEM and STEM/TEM showed dispersion in the polypropylene matrix. According to TGA and DSC measurements thermal behavior remain similar for all the composites. Mechanical test in tension demonstrate that modulus of the composites increases for all samples with a major impact for materials containing silanol groups synthetized in formic acid. Rheological measurements show a significantly increment in viscosity for samples containing unmodified and modified carbon nanotubes. No difference was found for samples containing silanol groups and halloysite when compared to neat polypropylene. Finally, the oxygen transmission rate increased for all samples showing high barrier properties only for samples containing natural and functionalized halloysite nanotubes.

  1. Hybrid Aluminum Composite Materials Based on Carbon Nanostructures

    Directory of Open Access Journals (Sweden)

    Tatiana S. Koltsova

    2015-09-01

    Full Text Available We investigated formation of carbon nanofibers grown by chemical deposition (CVD method using an acetylene-hydrogen mixture on the surface of micron-sized aluminum powder particles. To obtain uniform distribution of the carbon nanostructures on the particles we deposited nickel catalyst on the surface by spraying from the aqueous solution of nickel nitrate. It was found that increasing the time of the synthesis lowers the rate of growth of carbon nanostructures due to the deactivation of the catalyst. The Raman spectroscopy measurements confirm the presence of disordered carbon corresponding to CNFs in the specimen. X-ray photoelectron spectroscopy showed the presence of aluminum carbide in the hot pressed samples. An aluminum composite material prepared using 1 wt.% CNFs obtained by uniaxial cold pressing and sintering showed 30% increase in the hardness compared to pure aluminum, whereas the composites prepared by hot pressing showed 80% increase in the hardness. Composite materials have satisfactory ductility. Thus, the aluminum based material reinforced with carbon nanostructures should be appropriate for creating high-strength and light compacts for aerospace and automotive applications and power engineering.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7355

  2. Hybrid Composites Based on Carbon Fiber/Carbon Nanofilament Reinforcement

    Directory of Open Access Journals (Sweden)

    Mehran Tehrani

    2014-05-01

    Full Text Available Carbon nanofilament and nanotubes (CNTs have shown promise for enhancing the mechanical properties of fiber-reinforced composites (FRPs and imparting multi-functionalities to them. While direct mixing of carbon nanofilaments with the polymer matrix in FRPs has several drawbacks, a high volume of uniform nanofilaments can be directly grown on fiber surfaces prior to composite fabrication. This study demonstrates the ability to create carbon nanofilaments on the surface of carbon fibers employing a synthesis method, graphitic structures by design (GSD, in which carbon structures are grown from fuel mixtures using nickel particles as the catalyst. The synthesis technique is proven feasible to grow nanofilament structures—from ethylene mixtures at 550 °C—on commercial polyacrylonitrile (PAN-based carbon fibers. Raman spectroscopy and electron microscopy were employed to characterize the surface-grown carbon species. For comparison purposes, a catalytic chemical vapor deposition (CCVD technique was also utilized to grow multiwall CNTs (MWCNTs on carbon fiber yarns. The mechanical characterization showed that composites using the GSD-grown carbon nanofilaments outperform those using the CCVD-grown CNTs in terms of stiffness and tensile strength. The results suggest that further optimization of the GSD growth time, patterning and thermal shield coating of the carbon fibers is required to fully materialize the potential benefits of the GSD technique.

  3. Three-year randomised clinical trial to evaluate the clinical performance, quantitative and qualitative wear patterns of hybrid composite restorations.

    Science.gov (United States)

    Palaniappan, Senthamaraiselvi; Elsen, Liesbeth; Lijnen, Inge; Peumans, Marleen; Van Meerbeek, Bart; Lambrechts, Paul

    2010-08-01

    The aim of the study was to compare the clinical performance, quantitative and qualitative wear patterns of conventional hybrid (Tetric Ceram), micro-filled hybrid (Gradia Direct Posterior) and nano-hybrid (Tetric EvoCeram, TEC) posterior composite restorations in a 3-year randomised clinical trial. Sixteen Tetric Ceram, 17 TEC and 16 Gradia Direct Posterior restorations were placed in human molars and evaluated at baseline, 6, 12, 24 and 36 months of clinical service according to US Public Health Service criteria. The gypsum replicas at each recall were used for 3D laser scanning to quantify wear, and the epoxy resin replicas were observed under scanning electron microscope to study the qualitative wear patterns. After 3 years of clinical service, the three hybrid restorative materials performed clinically well in posterior cavities. Within the observation period, the nano-hybrid and micro-hybrid restorations evolved better in polishability with improved surface gloss retention than the conventional hybrid counterpart. The three hybrid composites showed enamel-like vertical wear and cavity-size dependant volume loss magnitude. Qualitatively, while the micro-filled and nano-hybrid composite restorations exhibited signs of fatigue similar to the conventional hybrid composite restorations at heavy occlusal contact area, their light occlusal contact areas showed less surface pitting after 3 years of clinical service.

  4. Behaviour of hybrid jute-glass/epoxy composite tubes subjected to lateral loading

    Science.gov (United States)

    Khalid, A. A.

    2015-12-01

    Experimental work on hybrid and non-hybrid composite tubes subjected to lateral loading has been carried out using jute, glass and hybrid jute-glass/epoxy materials. Tubes of 200 mm length with 110 mm inner diameter were fabricated by hand lay-up method to investigate the effect of material used and the number of layers on lateral-load-displacement relations and on the failure mode. Crush force efficiency and the specific energy absorption of the composite tubes were calculated. Results show that the six layers glass/epoxy tubes supported load higher 10.6% than that of hybrid jute-glass/ epoxy made of two layers of jute/epoxy four layers of glass/epoxy. It has been found that the specific energy absorption of the glass/epoxy tubes is found higher respectively 11.6% and 46% than hybrid jute-glass/epoxy and jute/epoxy tubes. The increase in the number of layers from two to six increases the maximum lateral load from 0.53KN to 1.22 KN for jute/epoxy and from 1.35 KN to 3.87 KN for the glass/epoxy tubes. The stacking sequence of the hybrid tubes influenced on the maximum lateral load and the absorbed energy. The maximum load obtained for the six layers jute-glass/epoxy tubes of different staking sequence varies between 1.88 KN to 3.46 KN. Failure mechanisms of the laterally loaded composite tubes were also observed and discussed.

  5. Hybrid local FEM/global LISA modeling of damped guided wave propagation in complex composite structures

    Science.gov (United States)

    Shen, Yanfeng; Cesnik, Carlos E. S.

    2016-09-01

    This paper presents a new hybrid modeling technique for the efficient simulation of guided wave generation, propagation, and interaction with damage in complex composite structures. A local finite element model is deployed to capture the piezoelectric effects and actuation dynamics of the transmitter, while the global domain wave propagation and interaction with structural complexity (structure features and damage) are solved utilizing a local interaction simulation approach (LISA). This hybrid approach allows the accurate modeling of the local dynamics of the transducers and keeping the LISA formulation in an explicit format, which facilitates its readiness for parallel computing. The global LISA framework was extended through the 3D Kelvin-Voigt viscoelasticity theory to include anisotropic damping effects for composite structures, as an improvement over the existing LISA formulation. The global LISA framework was implemented using the compute unified device architecture running on graphic processing units. A commercial preprocessor is integrated seamlessly with the computational framework for grid generation and material property allocation to handle complex structures. The excitability and damping effects are successfully captured by this hybrid model, with experimental validation using the scanning laser doppler vibrometry. To demonstrate the capability of our hybrid approach for complex structures, guided wave propagation and interaction with a delamination in a composite panel with stiffeners is presented.

  6. Effect of Moisture Absorption on the Mechanical Properties of Ceramic Filled Jute/Epoxy Hybrid Composites

    Science.gov (United States)

    Tapas Ranjan Swain, Priyadarshi; Biswas, Sandhyarani

    2017-02-01

    The present work emphasizes on the mechanical properties such as micro-hardness, flexural and impact strength of jute fiber and Al2O3 filler based polymer composites at dry and wet conditions. Composite samples reinforced with different wt.% of fibers and filler were prepared by hand lay-up technique. To improve the mechanical properties, jute fiber was hybridized with Al2O3 filler. The maximum flexural strength of 72.94 MPa and impact strength of 1.902 J is obtained for composites with 30 wt.% fiber content and 10 wt.% of filler content. The hardness of composite increases with increase in fiber and filler loading i.e 40 wt.% fiber content and 10 wt.% of filler content. The maximum hardness value is obtained 29.9 Hv. The effect of water absorption on mechanical properties of jute reinforced hybrid polymer composites is also investigated. To determine the influence of water absorption on the mechanical properties, specimens were immersed in distilled water for 10 days before testing. For reference purpose, dry specimens were tested. It is observed that the rate of water absorption depends on the fiber content as well as filler content. All the mechanical properties of composites are decreased after water absorption. Scanning electron microscopy (SEM) is used to characterise the microstructure and failure mechanisms of dry and wet jute fiber reinforced polymer composites.

  7. Morphology-controlled ZnO nanowire arrays for tailored hybrid composites with high damping.

    Science.gov (United States)

    Malakooti, Mohammad H; Hwang, Hyun-Sik; Sodano, Henry A

    2015-01-14

    Hybrid fiber reinforced composites using a nanoscale reinforcement of the interface have not reached their optimal performance in practical applications due to their complex design and the challenging assembly of their multiscale components. One promising approach to the fabrication of hybrid composites is the growth of zinc oxide (ZnO) nanowire arrays on the surface of carbon fibers to provide improved interfacial strength and out of plane reinforcement. However, this approach has been demonstrated mainly on fibers and thus still requires complex processing conditions. Here we demonstrate a simple approach to the fabrication of such composites through the growth of the nanowires on the fabric. The fabricated composites with nanostructured graded interphase not only exhibit remarkable damping enhancement but also stiffness improvement. It is demonstrated that these two extremely important properties of the composite can be controlled by tuning the morphology of the ZnO nanowires at the interface. Higher damping and flexural rigidity of these composites over traditional ones offer practical high-performance composites.

  8. STUDY OF MECHANICAL PROPERTIES OF BANANA-COIR HYBRID COMPOSITE USING EXPERIMENTAL AND FEM TECHNIQUES

    Directory of Open Access Journals (Sweden)

    T. Hariprasad

    2013-06-01

    Full Text Available The use of natural fibers as reinforcement in polymers has gained importance in recent years due to their eco-friendly nature. Thus, an investigation has been undertaken on banana-coir, which is a natural fiber abundantly available in India. Natural fibers are not only strong and lightweight, but also relatively very cheap. Composite plates were prepared with resin 392 g, coir 54 g, and banana 69 g. The purpose of this work is to establish the tensile, flexural, and impact properties of banana-coir reinforced composite materials with a thermo set for treated and untreated fibers. The resin used was epoxy (EP306. The tensile and impact tests showed that treated banana-coir epoxy hybrid composites have higher tensile strength and impact strength than untreated composites. However, untreated fiber composites have greater flexural strength than the treated fiber composites. The finite element analysis (FEA software ANSYS has been employed successfully to evaluate the properties. The stresses at the interface of the banana-coir and matrix, induced by the different loading conditions, were applied to predict the tensile, impact, and flexural properties by using the FEA models. The model output was compared with the experimental results and found to be close. This analysis is useful for realizing the advantages of hybrid fiber reinforced composites in structural applications and for identifying where the stresses are critical and damage the interface under varying loading conditions.

  9. Synthesis and characterization of hybrid silica/PMMA nanoparticles and their use as filler in dental composites.

    Science.gov (United States)

    Canché-Escamilla, G; Duarte-Aranda, S; Toledano, M

    2014-09-01

    The effect of hybrid silica/poly(methylmethacrylate) (PMMA) nanoparticles on the properties of composites for dental restoration was evaluated. Hybrid nanoparticles with silica as core and PMMA as shell were obtained by a seeded emulsion polymerization process. Fourier transform infrared spectrum of the hybrid nanoparticles shows an intense peak at 1,730 cm(-1), corresponding to carbonyl groups (CO) of the ester. The thermal stability of the hybrid particles decreases with increasing amounts of PMMA and the residual mass at 700°C corresponds to the silica content in the hybrid particles. Composites were obtained by dispersing nanoparticles (silica or hybrid), as fillers, in a resin-bis glycidyl dimethacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) (40%/60% (w/w)). The paste was then placed in a mold and polymerized under light irradiation. During the preparation of the composites, with the hybrid nanoparticles, the monomers swell the PMMA shell and after photo-curing, a semi-interpenetrating network (semi-IPN) is obtained around the silica core. The properties of the composites, obtained using the hybrid nanoparticles, depend on the filler content and the amount of PMMA in the semi-IPN matrix. For composites with similar inorganic filler contents, the composites with low amounts of PMMA shell had higher modulus than those in which silica was used as the filler. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Behavior of Aramid Fiber/Ultrahigh Molecular Weight Polyethylene Fiber Hybrid Composites under Charpy Impact and Ballistic Impact

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The aramid fiber/UHMWPE (ultrahigh molecular weight polyethylene) fiber hybrid composites (AF/DF) were manufactured. By Charpy impact, the low velocity impact behavior of AF/DF composite was studied. And the high velocity impact behavior under ballistic impact was also investigated. The influence of hybrid ratio on the performances of low and high velocity impact was analyzed, and hybrid structures with good impact properties under low velocity impact and high velocity were optimized. For Charpy impact, the maximal impact load increased with the accretion of the AF layers for AF/DF hybrid composites. The total impact power was reduced with the decrease of DF layers and the delamination can result in the increase of total impact power. For ballistic impact, the DF ballistic performance was better than that of the AF and the hybrid ratio had a crucial influence. The failure morphology of AF/DF hybrid composite under Charpy impact and ballistic impact was analyzed. The AF/DF hybrid composites in suitable hybrid ratio could attain better performance than AF or DF composites.

  11. Impact strength and flexural properties enhancement of methacrylate silane treated oil palm mesocarp fiber reinforced biodegradable hybrid composites.

    Science.gov (United States)

    Eng, Chern Chiet; Ibrahim, Nor Azowa; Zainuddin, Norhazlin; Ariffin, Hidayah; Yunus, Wan Md Zin Wan

    2014-01-01

    Natural fiber as reinforcement filler in polymer composites is an attractive approach due to being fully biodegradable and cheap. However, incompatibility between hydrophilic natural fiber and hydrophobic polymer matrix restricts the application. The current studies focus on the effects of incorporation of silane treated OPMF into polylactic acid (PLA)/polycaprolactone (PCL)/nanoclay/OPMF hybrid composites. The composites were prepared by melt blending technique and characterize the composites with Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). FTIR spectra indicated that peak shifting occurs when silane treated OPMF was incorporated into hybrid composites. Based on mechanical properties results, incorporation of silane treated OPMF enhances the mechanical properties of unmodified OPMF hybrid composites with the enhancement of flexural and impact strength being 17.60% and 48.43%, respectively, at 10% fiber loading. TGA thermogram shows that incorporation of silane treated OPMF did not show increment in thermal properties of hybrid composites. SEM micrographs revealed that silane treated OPMF hybrid composites show good fiber/matrix adhesion as fiber is still embedded in the matrix and no cavity is present on the surface. Water absorption test shows that addition of less hydrophilic silane treated OPMF successfully reduces the water uptake of hybrid composites.

  12. Impact Strength and Flexural Properties Enhancement of Methacrylate Silane Treated Oil Palm Mesocarp Fiber Reinforced Biodegradable Hybrid Composites

    Directory of Open Access Journals (Sweden)

    Chern Chiet Eng

    2014-01-01

    Full Text Available Natural fiber as reinforcement filler in polymer composites is an attractive approach due to being fully biodegradable and cheap. However, incompatibility between hydrophilic natural fiber and hydrophobic polymer matrix restricts the application. The current studies focus on the effects of incorporation of silane treated OPMF into polylactic acid (PLA/polycaprolactone (PCL/nanoclay/OPMF hybrid composites. The composites were prepared by melt blending technique and characterize the composites with Fourier transform infrared spectroscopy (FTIR, thermogravimetric analysis (TGA, and scanning electron microscopy (SEM. FTIR spectra indicated that peak shifting occurs when silane treated OPMF was incorporated into hybrid composites. Based on mechanical properties results, incorporation of silane treated OPMF enhances the mechanical properties of unmodified OPMF hybrid composites with the enhancement of flexural and impact strength being 17.60% and 48.43%, respectively, at 10% fiber loading. TGA thermogram shows that incorporation of silane treated OPMF did not show increment in thermal properties of hybrid composites. SEM micrographs revealed that silane treated OPMF hybrid composites show good fiber/matrix adhesion as fiber is still embedded in the matrix and no cavity is present on the surface. Water absorption test shows that addition of less hydrophilic silane treated OPMF successfully reduces the water uptake of hybrid composites.

  13. Processing investigation and optimization for hybrid thermoplastic composites

    Institute of Scientific and Technical Information of China (English)

    M Tufail

    2007-01-01

    A thermoplastic based composite material is suitable for automobile and aerospace applications. The recyclability of thermoplastic and clean processing further enhance its use. The only limitation encountered in using this material is its high-melt viscosity. Various techniques have been developed to overcome this problem. Commingled materials are one of such methods adopted for making proper use of thermoplastic. A major problem observed during the use of a commingled material is its de-commingling, wherein, the uniform distribution of fiber and thermoplastic yarn gets disturbed and affects the final quality of the composite. The effects of the braiding process on laminate quality were investigated. Flat plaques were produced by braiding the commingled yarn, using a 48-carrier braiding machine. The braids (and control woven samples) were subsequently heated and consolidated in a nonisothermal compression molding operation. Prior to the manufacture of the 'best quality' plaques, a series of moldings were produced under different consolidation conditions, to study the dependence of properties on the process variables. This enabled a processing window to be established for each material and helped to separate the respective effects of yarn handling, textile processing, and consolidation on laminate properties.

  14. Propagating edge states in strained honeycomb lattices

    Science.gov (United States)

    Salerno, Grazia; Ozawa, Tomoki; Price, Hannah M.; Carusotto, Iacopo

    2017-06-01

    We investigate the helically propagating edge states associated with pseudo-Landau levels in strained honeycomb lattices. We exploit chiral symmetry to derive a general criterion for the existence of these propagating edge states in the presence of only nearest-neighbor hoppings and we verify our criterion using numerical simulations of both uniaxially and trigonally strained honeycomb lattices. We show that the propagation of the helical edge state can be controlled by engineering the shape of the edges. Sensitivity to chiral-symmetry-breaking next-nearest-neighbor hoppings is assessed. Our result opens up an avenue toward the precise control of edge modes through manipulation of the edge shape.

  15. Characterizations of Polystyrene-Based Hybrid Particles Containing Hydrophobic Mg(OH2 Powder and Composites Fabricated by Employing Resultant Hybrid Particles

    Directory of Open Access Journals (Sweden)

    Shuichi Kimura

    2007-01-01

    unchanged, even when the ST-1 powder content increased from 10 to 50 phr. Furthermore, a composite fabricated by employing the hybrid particles achieved homogenous distribution of ST-1 powder and showed a higher oxygen index than that of a composite fabricated by directly mixing of PS pellets and ST-1 powder.

  16. Effect of Coconut Fillers on Hybrid Coconut Kevlar Fiber Reinforced Epoxy Composites

    Directory of Open Access Journals (Sweden)

    S. P. Jani

    2015-12-01

    Full Text Available This project focuses on the conversion of naturally available coconut fibers and shells into a useful composite. In addition to it, some mechanical properties of the resultant composite is determined and also the effect of coconut shell fillers on the composite is also investigated. The few portion of the composite is incorporated with synthetic Kevlar fiber, thus the coconut fiber is hybridized to enhance the mechanical properties of coconut. In this work two types of composite is fabricate, kevelar coconut fibre (kc composite and kevelarcoco nut fibre coconut shell filler (kccsf composite. Coconut fibers have low weight and considerable properties among the natural fibers, while coconut fillers have a good ductile and impact property. The natural fibers and fillers are treated with Na-OH to make it free of organic impurities. Epoxy resin is used as the polymer matrix. Two composite are produced one with fillers and the other without the fillers using compression molding method. Mechanical properties like tensile strength, flexural strength and water absorption tests are done with ASTM standard. It is observed that that the addition of filler materials improves the adhesiveness of the fibers leading to the increase in the above mentioned properties. The density of the composite is also low hence the strength to weight ratio is very high. The water absorption test also showed that the resultant composite had a small adhesion to water and absorption of water.

  17. Effect of Short Fiber Reinforcement on Mechanical Properties of Hybrid Phenolic Composites

    Directory of Open Access Journals (Sweden)

    Sembian Manoharan

    2014-01-01

    Full Text Available Fiber plays an important role in determining the hardness, strength, and dynamic mechanical properties of composite material. In the present work, enhancement of viscoelastic behaviour of hybrid phenolic composites has been synergistically investigated. Five different phenolic composites, namely, C1, C2, C3, C4, and C5, were fabricated by varying the weight percentage of basalt and aramid fiber, namely, 25, 20, 15, 10, and 5% by compensating with barium sulphate (BaSO4 to keep the combined reinforcement concentration at 25 wt%. Hardness was measured to examine the resistance of composites to indentation. The hardness of phenolic composites increased from 72.2 to 85.2 with increase in basalt fiber loading. Composite C1 (25 wt% fiber is 1.2 times harder than composite C5. Compression test was conducted to find out compressive strength of phenolic composites and compressive strength increased with increase in fiber content. Dynamic mechanical analysis (DMA was carried out to assess the temperature dependence mechanical properties in terms of storage modulus (E′, loss modulus (E′′, and damping factor (tan δ. The results indicate great improvement of E′ values and decrease in damping behaviour of composite upon fiber addition. Further X-ray powder diffraction (XRD and energy-dispersive X-ray (EDX analysis were employed to characterize the friction composites.

  18. Studies on Effective Elastic Properties of CNT/Nano-Clay Reinforced Polymer Hybrid Composite

    Science.gov (United States)

    Thakur, Arvind Kumar; Kumar, Puneet; Srinivas, J.

    2016-02-01

    This paper presents a computational approach to predict elastic propertiesof hybrid nanocomposite material prepared by adding nano-clayplatelets to conventional CNT-reinforced epoxy system. In comparison to polymers alone/single-fiber reinforced polymers, if an additional fiber is added to the composite structure, it was found a drastic improvement in resultant properties. In this regard, effective elastic moduli of a hybrid nano composite are determined by using finite element (FE) model with square representative volume element (RVE). Continuum mechanics based homogenization of the nano-filler reinforced composite is considered for evaluating the volumetric average of the stresses and the strains under different periodic boundary conditions.A three phase Halpin-Tsai approach is selected to obtain the analytical result based on micromechanical modeling. The effect of the volume fractions of CNTs and nano-clay platelets on the mechanical behavior is studied. Two different RVEs of nano-clay platelets were used to investigate the influence of nano-filler geometry on composite properties. The combination of high aspect ratio of CNTs and larger surface area of clay platelets contribute to the stiffening effect of the hybrid samples. Results of analysis are validated with Halpin-Tsai empirical formulae.

  19. Tribological performance of Graphene/Carbon nanotube hybrid reinforced Al2O3 composites

    Science.gov (United States)

    Yazdani, Bahareh; Xu, Fang; Ahmad, Iftikhar; Hou, Xianghui; Xia, Yongde; Zhu, Yanqiu

    2015-06-01

    Tribological performance of the hot-pressed pure Al2O3 and its composites containing various hybrid contents of graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) were investigated under different loading conditions using the ball-on-disc method. Benchmarked against the pure Al2O3, the composite reinforced with a 0.5 wt% GNP exhibited a 23% reduction in the friction coefficient along with a promising 70% wear rate reduction, and a hybrid reinforcement consisting of 0.3 wt.% GNPs + 1 wt.% CNTs resulted in even better performance, with a 86% reduction in the wear rate. The extent of damage to the reinforcement phases caused during wear was studied using Raman spectroscopy. The wear mechanisms for the composites were analysed based on the mechanical properties, brittleness index and microstructural characterizations. The excellent coordination between GNPs and CNTs contributed to the excellent wear resistance property in the hybrid GNT-reinforced composites. GNPs played the important role in the formation of a tribofilm on the worn surface by exfoliation; whereas CNTs contributed to the improvement in fracture toughness and prevented the grains from being pulled out during the tribological test.

  20. Quantifying Alumina Nanoparticle Dispersion in Hybrid Carbon Fiber Composites Using Photoluminescent Spectroscopy.

    Science.gov (United States)

    Hanhan, Imad; Selimov, Alex; Carolan, Declan; Taylor, Ambrose C; Raghavan, Seetha

    2017-02-01

    Composites modified with nanoparticles are of interest to many researchers due to the large surface-area-to-volume ratio of nano-scale fillers. One challenge with nanoscale materials that has received significant attention is the dispersion of nanoparticles in a matrix material. A random distribution of particles often ensures good material properties, especially as it relates to the thermal and mechanical performance of composites. Typical methods to quantify particle dispersion in a matrix material include optical, scanning electron, and transmission electron microscopy. These utilize images and a variety of analysis methods to describe particle dispersion. This work describes how photoluminescent spectroscopy can serve as an additional technique capable of quickly and comprehensively quantifying particle dispersion of photoluminescent particles in a hybrid composite. High resolution 2D photoluminescent maps were conducted on the front and back surfaces of a hybrid carbon fiber reinforced polymer containing varying contents of alumina nanoparticles. The photoluminescent maps were analyzed for the intensity of the alumina R1 fluorescence peak, and therefore yielded alumina particle dispersion based on changes in intensity from the embedded nanoparticles. A method for quantifying particle sedimentation is also proposed that compares the photoluminescent data of the front and back surfaces of each hybrid composite and assigns a single numerical value to the degree of sedimentation in each specimen. The methods described in this work have the potential to aid in the manufacturing processes of hybrid composites by providing on-site quality control options, capable of quickly and noninvasively providing feedback on nanoparticle dispersion and sedimentation.

  1. Influence of Hybridizing Flax and Hemp-Agave Fibers with Glass Fiber as Reinforcement in a Polyurethane Composite

    Directory of Open Access Journals (Sweden)

    Pankaj Pandey

    2016-05-01

    Full Text Available In this study, six combinations of flax, hemp, and glass fiber were investigated for a hybrid reinforcement system in a polyurethane (PU composite. The natural fibers were combined with glass fibers in a PU composite in order to achieve a better mechanical reinforcement in the composite material. The effect of fiber hybridization in PU composites was evaluated through physical and mechanical properties such as water absorption (WA, specific gravity (SG, coefficient of linear thermal expansion (CLTE, flexural and compression properties, and hardness. The mechanical properties of hybridized samples showed mixed trends compared to the unhybridized samples, but hybridization with glass fiber reduced water absorption by 37% and 43% for flax and hemp-agave PU composites respectively.

  2. Effect of fibre orientations on the mechanical properties of kenaf–aramid hybrid composites for spall-liner application

    Institute of Scientific and Technical Information of China (English)

    R. YAHAYA; S.M. SAPUAN; M. JAWAID; Z. LEMAN; E.S. ZAINUDIN

    2016-01-01

    This paper presents the effect of kenaf fibre orientation on the mechanical properties of kenaf–aramid hybrid composites for military vehicle's spall liner application. It was observed that the tensile strength of woven kenaf hybrid composite is almost 20.78%and 43.55%higher than that of UD and mat samples respectively. Charpy impact strength of woven kenaf composites is 19.78%and 52.07%higher than that of UD and mat kenaf hybrid composites respectively. Morphological examinations were carried out using scanning electron microscopy. The results of this study indicate that using kenaf in the form of woven structure could produce a hybrid composite material with high tensile strength and impact resistance properties.

  3. Wear Behavior of Aluminum Matrix Hybrid Composites Fabricated through Friction Stir Welding Process

    Institute of Scientific and Technical Information of China (English)

    Halil Ibrahim KURT; Murat ODUNCUOGLU; Ramazan ASMATULU

    2016-01-01

    Effects of friction stir processing (FSP)parameters and reinforcements on the wear behavior of 6061-T6 based hybrid composites were investigated.A mathematical formulation was derived to calculate the wear volume loss of the composites.The experimental results were contrasted with the results of the proposed model.The influ-ences of sliding distance,tool traverse and rotational speeds,as well as graphite (Gr)and titanium carbide (TiC) volume fractions on the wear volume loss of the composites were also investigated using the prepared formulation. The results demonstrated that the wear volume loss of the composites significantly increased with increasing sliding distance,tool traverse speed,and rotational speed;while the wear volume loss decreased with increasing volume fraction of the reinforcements.A minimum wear volume loss for the hybrid composites with complex reinforcements was specified at the inclusion ratio of 50% TiC+50% Al2 O3 because of improved lubricant ability,as well as resist-ance to brittleness and wear.New possibilities to develop wear-resistant aluminum-based composites for different in-dustrial applications were proposed.

  4. Mechanical Characterization and Water Absorption Behaviour of Interwoven Kenaf/PET Fibre Reinforced Epoxy Hybrid Composite

    Directory of Open Access Journals (Sweden)

    Yakubu Dan-mallam

    2015-01-01

    Full Text Available The development of interwoven fabric for composite production is a novel approach that can be adopted to address the challenges of balanced mechanical properties and water absorption behaviour of polymer composites. In this paper, kenaf and PET (polyethylene terephthalate fibre were selected as reinforcing materials to develop the woven fabric, and low viscosity epoxy resin was chosen as the matrix. Vacuum infusion process was adopted to produce the hybrid composite due to its superior advantages over hand lay-up technique. The weight percentage composition of the Epoxy/kenaf/PET hybrid composite was maintained at 70/15/15 and 60/20/20, respectively. A significant increase in tensile strength and elastic modulus of approximately 73% and 53% was recorded in relation to neat epoxy. Similarly, a substantial increase in flexural, impact, and interlaminar properties was also realized in relation to neat epoxy. This enhancement in mechanical properties may be attributed to the interlocking structure of the interwoven fabric, individual properties of kenaf and PET fibres, strong interfacial bonding, and resistance of the fibres to impact loading. The water absorption of the composites was studied by prolonged exposure in distilled water, and the moisture absorption pattern was found to follow Fickian behaviour.

  5. Dry Process for Manufacturing Hybridized Boron Fiber/Carbon Fiber Thermoplastic Composite Materials from a Solution Coated Precursor

    Science.gov (United States)

    Belvin, Harry L. (Inventor); Cano, Roberto J. (Inventor)

    2003-01-01

    An apparatus for producing a hybrid boron reinforced polymer matrix composite from precursor tape and a linear array of boron fibers. The boron fibers are applied onto the precursor tapes and the precursor tape processed within a processing component having an impregnation bar assembly. After passing through variable-dimension forming nip-rollers, the precursor tape with the boron fibers becomes a hybrid boron reinforced polymer matrix composite. A driving mechanism is used to pulled the precursor tape through the method and a take-up spool is used to collect the formed hybrid boron reinforced polymer matrix composite.

  6. Two-year clinical comparison of a flowable-type nano-hybrid composite and a paste-type composite in posterior restoration.

    Science.gov (United States)

    Hirata-Tsuchiya, Shizu; Yoshii, Shinji; Ichimaru-Suematsu, Miki; Washio, Ayako; Saito, Noriko; Urata, Mariko; Hanada, Kaori; Morotomi, Takahiko; Kitamura, Chiaki

    2017-08-01

    The purpose of the present study was to compare the clinical efficacy between a flowable-type nano-hybrid composite and a paste-type composite for posterior restoration. Of 62 posterior teeth in 33 patients (mean age: 34.1 years), 31 were filled with a paste-type composite (Heliomolar [HM] group), and another 31 with a flowable nano-hybrid composite (MI FIL [MI] group). Clinical efficacy was evaluated at 2 years after the restoration. There were no differences for retention, surface texture deterioration, anatomical form change, deterioration of marginal adaptation, and secondary caries, while a statistical difference was found for marginal discoloration, which was significantly greater in the HM group (P composites showed that the flowable nano-hybrid composite could be an effective esthetic material for posterior restoration. © 2016 John Wiley & Sons Australia, Ltd.

  7. Investigation on effect of fibre hybridization and orientation on mechanical behaviour of natural fibre epoxy composite

    Indian Academy of Sciences (India)

    P KALIAPPAN; R KESAVAN; B VIJAYA RAMNATH

    2017-08-01

    Nowadays bio fibre composites play a vital role by replacing conventional materials used in automotive andaerospace industries owing to their high strength to weight ratio, biodegradability and ease of production. This paper aimsto find the effect of fibre hybridization and orientation on mechanical behaviour of composite fabricated with neem, abacafibres and epoxy resin. Here, three varieties of composites are fabricated namely, composite 1 which consists of abaca fibreand glass fibre, composite 2, which consists of neem fibre and glass fibre, whereas composite 3 consists of abaca, neem fibresand glass fibres. In all the above three varieties, fibres are arranged in three types of orientations namely, horizontal (type I),vertical (type II) and 45$^{\\circ}$ inclination (type III). The result shows that composites made up of abaca and neem fibres withinclined orientation (45$^{\\circ}$) have better mechanical properties when compared with other types of composites. In addition, morphological analysis is carried out using scanning electron microscope to know the fibre distribution, fibre pull out, fibre breakage and crack propagation on tested composites.

  8. Randomized controlled split-mouth clinical trial of direct laminate veneers with two micro-hybrid resin composites

    NARCIS (Netherlands)

    Gresnigt, Marco M. M.; Kalk, Warner; Ozcan, M.; Ozcan, Mutlu

    Objectives: This randomized, split-mouth clinical study evaluated the survival rate of direct laminate veneers made of two resin-composite materials. Methods: A total of 23 patients (mean age: 52.4 years old) received 96 direct composite laminate veneers using two micro-hybrid composites in

  9. Randomized controlled split-mouth clinical trial of direct laminate veneers with two micro-hybrid resin composites

    NARCIS (Netherlands)

    Gresnigt, Marco M. M.; Kalk, Warner; Ozcan, M.; Ozcan, Mutlu

    2012-01-01

    Objectives: This randomized, split-mouth clinical study evaluated the survival rate of direct laminate veneers made of two resin-composite materials. Methods: A total of 23 patients (mean age: 52.4 years old) received 96 direct composite laminate veneers using two micro-hybrid composites in combinat

  10. A model updating method for hybrid composite/aluminum bolted joints using modal test data

    Science.gov (United States)

    Adel, Farhad; Shokrollahi, Saeed; Jamal-Omidi, Majid; Ahmadian, Hamid

    2017-05-01

    The aim of this paper is to present a simple and applicable model for predicting the dynamic behavior of bolted joints in hybrid aluminum/composite structures and its model updating using modal test data. In this regards, after investigations on bolted joints in metallic structures which led to a new concept called joint affected region (JAR) published in Shokrollahi and Adel (2016), now, a doubly connective layer is established in order to simulate the bolted joint interfaces in hybrid structures. Using the proposed model, the natural frequencies of the hybrid bolted joint structure are computed and compared to the modal test results in order to evaluate and verify the new model predictions. Because of differences in the results of two approaches, the finite element (FE) model is updated based on the genetic algorithm (GA) by minimizing the differences between analytical model and test results. This is done by identifying the parameters at the JAR including isotropic Young's modulus in metallic substructure and that of anisotropic composite substructure. The updated model compared to the initial model simulates experimental results more properly. Therefore, the proposed model can be used for modal analysis of the hybrid joint interfaces in complex and large structures.

  11. Drilling of Hybrid Titanium Composite Laminate (HTCL with Electrical Discharge Machining

    Directory of Open Access Journals (Sweden)

    M. Ramulu

    2016-09-01

    Full Text Available An experimental investigation was conducted to determine the application of die sinker electrical discharge machining (EDM as it applies to a hybrid titanium thermoplastic composite laminate material. Holes were drilled using a die sinker EDM. The effects of peak current, pulse time, and percent on-time on machinability of hybrid titanium composite material were evaluated in terms of material removal rate (MRR, tool wear rate, and cut quality. Experimental models relating each process response to the input parameters were developed and optimum operating conditions with a short cutting time, achieving the highest workpiece MRR, with very little tool wear were determined to occur at a peak current value of 8.60 A, a percent on-time of 36.12%, and a pulse time of 258 microseconds. After observing data acquired from experimentation, it was determined that while use of EDM is possible, for desirable quality it is not fast enough for industrial application.

  12. High-Temperature Fatigue of a Hybrid Aluminum Metal Matrix Composite

    Science.gov (United States)

    Clark, J. T.; Sanders, P. G.

    2014-01-01

    An aluminum metal matrix composite (MMC) brake drum was tested in fatigue at room temperature and extreme service temperatures. At room temperature, the hybrid composite did not fail and exceeded estimated vehicle service times. At higher temperatures (62 and 73 pct of the matrix eutectic), fatigue of a hybrid particle/fiber MMC exhibited failure consistent with matrix overloading. Overaging of the A356 matrix coupled with progressive fracture of the SiC particles combined to create the matrix overload condition. No evidence of macro-fatigue crack initiation or growth was observed, and the matrix-particle interface appeared strong with no debonding, visible matrix phases, or porosity. An effective medium model was constructed to test the hypothesis that matrix overloading was the probable failure mode. The measured particle fracture rate was fit using realistic values of the SiC Weibull strength and modulus, which in turn predicted cycles to failure within the range observed in fatigue testing.

  13. On the assumption of transverse isotropy of a honeycomb sandwich panel for NDT applications

    Science.gov (United States)

    Schaal, Christoph; Tai, Steffen; Mal, Ajit

    2017-04-01

    Due to their excellent strength-to-weight ratio, honeycomb sandwich panels are being increasingly used in lightweight structures, in particular in aircraft and aerospace industry. Delaminations of individual plies in the composite skins or disbonds of a layer in the multi-layer plate structures often remain undetected during visual inspection. Using guided ultrasonic waves, such hidden defects can be detected. For the successful application of ultrasonic nondestructive testing methods, however, wave propagation characteristics have to be well-understood. Recently developed semi-analytical techniques allow for the calculation of dispersion characteristics for many materials. However, the elastic material behavior is often simplified for these calculations. For example, woven composite laminates are modeled as a homogeneous, transversely isotropic plate. While these simplifications only lead to minor errors, the modeling of aluminum honeycomb core sandwich panels with homogeneous, transversely isotropic layers has yet to be validated. In this paper, an efficient numerical approach is used to determine the dispersion characteristics of a honeycomb core layer with and without simplified material behavior. A full 3D-model, including the honeycomb cells, of a small representative volume element of the material is generated using finite elements, and the resulting dispersion curves are compared to the ones obtained from simplified models. In addition to dispersion curves, the displacement fields of the waves are also analyzed.

  14. Flexural Properties of E Glass and TR50S Carbon Fiber Reinforced Epoxy Hybrid Composites

    Science.gov (United States)

    Dong, Chensong; Sudarisman; Davies, Ian J.

    2013-01-01

    A study on the flexural properties of E glass and TR50S carbon fiber reinforced hybrid composites is presented in this paper. Specimens were made by the hand lay-up process in an intra-ply configuration with varying degrees of glass fibers added to the surface of a carbon laminate. These specimens were then tested in the three-point bend configuration in accordance with ASTM D790-07 at three span-to-depth ratios: 16, 32, and 64. The failure modes were examined under an optical microscope. The flexural behavior was also simulated by finite element analysis, and the flexural modulus, flexural strength, and strain to failure were calculated. It is shown that although span-to-depth ratio shows an influence on the stress-strain relationship, it has no effect on the failure mode. The majority of specimens failed by either in-plane or out-of-plane local buckling followed by kinking and splitting at the compressive GFRP side and matrix cracking combined with fiber breakage at the CFRP tensile face. It is shown that positive hybrid effects exist for the flexural strengths of most of the hybrid configurations. The hybrid effect is noted to be more obvious when the hybrid ratio is small, which may be attributed to the relative position of the GFRP layer(s) with respect to the neutral plane. In contrast to this, flexural modulus seems to obey the rule of mixtures equation.

  15. A review of composite material applications in the automotive industry for the electric and hybrid vehicle

    Science.gov (United States)

    Bauer, J. L.

    1979-01-01

    A review is made of the state-of-the-art in regard to the use of composite materials for reducing the structural mass of automobiles. Reduction of mass provides, in addition to other engineering improvements, increased performance/range advantages that are particularly needed in the electric and hybrid vehicle field. Problems encountered include the attainment of mass production techniques and the prevention of environmental hazards.

  16. Semiconductor Nanocrystals Hybridized with Functional Ligands: New Composite Materials with Tunable Properties

    Directory of Open Access Journals (Sweden)

    Nathan I. Hammer

    2010-01-01

    Full Text Available Semiconductor nanocrystals hybridized with functional ligands represent an important new class of composite nanomaterials. The development of these new nanoscale building blocks has intensified over the past few years and offer significant advantages in a wide array of applications. Functional ligands allow for incorporation of nanocrystals into areas where their unique photophysics can be exploited. Energy and charge transfer between the ligands and the nanocrystal also result in enhanced physical properties that can be tuned by the choice of ligand architecture. Here, progress in the development and applications involving this new class of composite materials will be discussed.

  17. Hybrid composites of monodisperse pi-conjugated rodlike organic compounds and semiconductor quantum particles

    DEFF Research Database (Denmark)

    Hensel, V.; Godt, A.; Popovitz-Biro, R.

    2002-01-01

    Composite materials of quantum particles (Q-particles) arranged in layers within crystalline powders of pi-conjugated, rodlike dicarboxylic acids are reported. The synthesis of the composites, either as three-dimensional crystals or as thin films at the air-water interface, comprises a two...... analysis of the solids and grazing incidence X-ray diffraction analysis of the films on water. 2) Topotactic solid/gas reaction of these salts with H2S to convert the metal ions into Q-particles of CdS or PbS embedded in the organic matrix that consists of the acids 6(H) and 8(H). These hybrid materials...

  18. Inserting Stress Analysis of Combined Hexagonal Aluminum Honeycombs

    Directory of Open Access Journals (Sweden)

    Xiangcheng Li

    2016-01-01

    Full Text Available Two kinds of hexagonal aluminum honeycombs are tested to study their out-of-plane crushing behavior. In the tests, honeycomb samples, including single hexagonal aluminum honeycomb (SHAH samples and two stack-up combined hexagonal aluminum honeycombs (CHAH samples, are compressed at a fixed quasistatic loading rate. The results show that the inserting process of CHAH can erase the initial peak stress that occurred in SHAH. Meanwhile, energy-absorbing property of combined honeycomb samples is more beneficial than the one of single honeycomb sample with the same thickness if the two types of honeycomb samples are completely crushed. Then, the applicability of the existing theoretical model for single hexagonal honeycomb is discussed, and an area equivalent method is proposed to calculate the crushing stress for nearly regular hexagonal honeycombs. Furthermore, a semiempirical formula is proposed to calculate the inserting plateau stress of two stack-up CHAH, in which structural parameters and mechanics properties of base material are concerned. The results show that the predicted stresses of three kinds of two stack-up combined honeycombs are in good agreement with the experimental data. Based on this study, stress-displacement curve of aluminum honeycombs can be designed in detail, which is very beneficial to optimize the energy-absorbing structures in engineering fields.

  19. OUT-OF-PLANE COMPRESSIVE PROPERTIES OF HEXAGONAL PAPER HONEYCOMBS

    Institute of Scientific and Technical Information of China (English)

    WANG Dongmei; WANG Zhiwei

    2007-01-01

    The compressive behaviour of paper honeycombs is studied by means of an experimental analysis. Experiment results show how geometry aspects of hexagonal paper honeycombs, e.g. the height of paper honeycomb, the thickness and length of honeycomb cell-wall, the drawing ratio of hexagonal honeycomb, affect the compressive properties of the paper honeycombs. It is in good agreement with the theory model. The constraint factor K of the critical buckling stress is mainly determined by the length of honeycomb cell-wall. It can be described as K=1.54 for B type paper honeycombs and K=3.32 for D type paper honeycombs. The plateau stress is the power exponent function of the thickness to length ratio of honeycomb cell-wall, and the experiment results show that the constant is 13.2 and the power exponent is 1.77. The research results can be used to characterize and improve efficiently the compressive properties of paper honeycombs.

  20. Physico-mechanical and tribological properties of Grewia Optiva fiber/bio-particulates hybrid polymer composites

    Science.gov (United States)

    Kumar, Sandeep; Gangil, Brijesh; Patel, Vinay Kumar

    2016-05-01

    Lack of resources and increasing environmental issues has received widespread attention for the development of natural fiber/ particulate reinforced hybrid polymer composites. In the present investigation the authors use (GO) Grewia Optiva as the main reinforcement and rice husk/wheat straw as additional particulates for improving the mechanical and wear properties of polymer composites. The samples were prepared by hand layup technique according to ASTM standards. The results indicated that incorporation of wheat straw with GO polymer materials exhibited better hardness (2.5 times harder) and less wear (0.85 times) than mono GO fiber polymer composites (GOFRP). Moreover, Rice husk filled GOFRP shows superior impact energy among the all set of composites. Water absorption behavior was also discussed in this investigation.

  1. Optimization and Static Stress Analysis of Hybrid Fiber Reinforced Composite Leaf Spring

    Directory of Open Access Journals (Sweden)

    Luay Muhammed Ali Ismaeel

    2015-01-01

    Full Text Available A monofiber reinforced composite leaf spring is proposed as an alternative to the typical steel one as it is characterized by high strength-to-weight ratio. Different reinforcing schemes are suggested to fabricate the leaf spring. The composite and the typical steel leaf springs are subjected to the same working conditions. A weight saving of about more than 60% can be achieved while maintaining the strength for the structures under consideration. The objective of the present study was to replace material for leaf spring. This study suggests various materials of hybrid fiber reinforced plastics (HFRP. Also the effects of shear moduli of the fibers, matrices, and the composites on the composites performance and responses are discussed. The results and behaviors of each are compared with each other and verified by comparison with analytical solution; a good convergence is found between them. The elastic properties of the hybrid composites are calculated using rules of mixtures and Halpin-Tsi equation through the software of MATLAB v-7. The problem is also analyzed by the technique of finite element analysis (FEA through the software of ANSYS v-14. An element modeling was done for every leaf with eight-node 3D brick element (SOLID185 3D 8-Node Structural Solid.

  2. MAX Phase Modified SiC Composites for Ceramic-Metal Hybrid Cladding Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yang-Il; Kim, Sun-Han; Park, Dong-Jun; Park, Jeong-Hwan; Park, Jeong-Yong; Kim, Hyun-Gil; Koo, Yang-Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    A metal-ceramic hybrid cladding consists of an inner zirconium tube, and an outer SiC fiber-matrix SiC ceramic composite with surface coating as shown in Fig. 1 (left-hand side). The inner zirconium allows the matrix to remain fully sealed even if the ceramic matrix cracks through. The outer SiC composite can increase the safety margin by taking the merits of the SiC itself. In addition, the outermost layer prevents the dissolution of SiC during normal operation. On the other hand, a ceramic-metal hybrid cladding consists of an outer zirconium tube, and an inner SiC ceramic composite as shown in Fig. 1 (right-hand side). The outer zirconium protects the fuel rod from a corrosion during reactor operation, as in the present fuel claddings. The inner SiC composite, additionally, is designed to resist the severe oxidation under a postulated accident condition of a high-temperature steam environment. Reaction-bonded SiC was fabricated by modifying the matrix as the MAX phase. The formation of Ti{sub 3}SiC{sub 2} was investigated depending on the compositions of the preform and melt. In most cases, TiSi{sub 2} was the preferential phase because of its lowest melting point in the Ti-Si-C system. The evidence of Ti{sub 3}SiC{sub 2} was the connection with the pressurizing.

  3. Strengthening in and fracture behaviour of CNT and carbon-fibrereinforced epoxy–matrix hybrid composite

    Indian Academy of Sciences (India)

    K CHANDRA SHEKAR; B ANJANEYA PRASAD; N ESWARA PRASAD

    2016-12-01

    Advanced materials such as continuous fibre-reinforced polymer matrix composites offer significant enhancements in strength and fracture resistance properties as compared with their bulk, monolithic counterparts. In the present work, mode-I (tensile) fracture behaviour of the neat epoxy (without nano- or hybrid reinforcements), nanocomposite (with amino-functionalized multi-walled carbon nanotube (MWCNT) reinforcement to neat epoxy) and hybrid composite (with amino MWCNT and carbon fibre reinforcements to neat epoxy) along with their flexural strength and interlaminar shear strength has been reported and discussed.Limited topological studies have also been conducted to understand the nature of material fracture and its dependence on the notch orientation. The results thus obtained are analysed and discussed in detail to elucidate:(i) alignment of fibre and its influence on the anisotropy in strength and fracture resistance, (ii) dependence of notch root radii on the apparent fracture toughness and concurrence to strain-controlled fracture and (iii) finally, the nature of J–R curves. The results thus obtained have revealed that the resistance to fracture is significantlyincreased with the addition of amino-functionalized MWCNTs and carbon fibres. In the hybrid composite, fracture resistance is greater in the longitudinal orientation of fibres than in the transverse orientation and it exhibits a significantly higher strength–fracture toughness combination.

  4. Fabrication of copper-ceria hybrid composite electrode for electrocatalytic oxidation of methanol

    Institute of Scientific and Technical Information of China (English)

    LI Jing; LI Lijun; YU Yuting; GAO Yanfang; LIU Jinrong

    2013-01-01

    Copper-ceria hybrid composite electrode prepared by electrochemical co-deposition was examined for their redox process and electrocatalytic activities towards the oxidation of methanol.The structure and morphology of electrodes were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM),respectively.XRD pattern of the copper-ceria hybrid composite electrode exhibited some diffraction peaks of CeO2 and SEM micrograph showed that it was composed of grains and flakes.The energy dispersive spectroscopy (EDS) spectrum of this area also showed the presence of cerium.Cyclic voltammetry,CO stripping and chronoamperometry were performed to characterize electrocatalytic property of the prepared samples.In cyclic voltammetry studies and chronoamperometry,copper-ceria hybrid composite electrode towards oxidation of methanol showed a significantly higher response and long term stability.CO stripping results indicated the facile removal of intermediate poisoning species CO in the presence of CeO2,which was helpful for CO and methanol electro-oxidation.

  5. Processing and study of the wear and friction behaviour of discrete graded Cu hybrid composites

    Indian Academy of Sciences (India)

    T Ram Prabhu

    2015-06-01

    Discrete functionally graded composites are the novel composites which have high potential in the brake friction material applications. In this paper, we have prepared discrete functional graded Cu/10%SiC/20%graphite(Gr)/10%boron nitride (h-BN) hybrid composites by the layer stacking compaction and pressure sintering techniques.We have considered two types of composites based on h-BN particle sizes. The size ranges of h-BN used were 140–180 and 3–25 m. The friction and wear properties of the composites were evaluated in a laboratory scale brake inertial dynamometer at low (5, 10 m s−1) and high sliding speeds (30, 35 m s−1) and, high braking load (2000 N) conditions. In addition, we have performed microstructure characterization, density, hardness and flexural strength measurements.Wear surface morphology studies were also carried out using stereoscope and scanning electron microscope. Our experiments lead to the following important results: (1) the large size h-BN particle improves the densification of the hybridized composite layer and provides higher wear resistance and better braking performance at all sliding speeds, (2) the wear loss (by mass) and the stopping distance/time increase with sliding speeds due to the increase in the braking energy, (3) at low sliding speeds (5, 10 m s−1), abrasive wear is the main wear mechanism, whereas many different wear mechanisms (delamination, oxidation, abrasive) are cooccuring at higher sliding speeds (30, 35 m s−1), (4) the mechanical properties (flexural strength and surface hardness) of composites are not affected by the h-BN particle size, (5) the incorporation of copper layer in the discrete layer structure deflects and arrests the crack at the copper/composite layer interface, thus improving the fracture resistance in addition to improving the bulk thermal conductivity.

  6. Mechanical properties and production quality of hand-layup and vacuum infusion processed hybrid composite materials for GFRP marine structures

    National Research Council Canada - National Science Library

    Kim Sang-Young; Shim Chun Sik; Sturtevant Caleb; Kim Dave (Dae-Wook); Song Ha Cheol

    2014-01-01

    .... This paper aims to investigate the mechanical properties and failure mechanisms of the hybrid GFRP composites, formed by applying the hand lay-up processed exterior and the vacuum infusion processed...

  7. Final report on the Blisk- and Composite-Hybrid Technology project. Final report; Schlussbericht zum Blisk- und Composite-Hybrid-Technologie Vorhaben. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Wenger, U.; Schoth, U.

    2000-04-01

    Blade Integrated Disks (BLISK) have been developed and tested in Rolls-Royce GmbH as part of the German government funded aviation technology program 'Engine 3E' (Environment, Economy and Efficiency). Blisk technology offers up to 30% weight saving potential for compressor rotors. Using modern manufacturing strategies Blisks also offer the opportunity for cost savings of up to 10%. Part life cycle costs are not only manufacturing costs but include also maintenance and repair. Blisks can therefore only be introduced into civil engines if damage can be repaired economically. Therefore, weld repair of Blisks has been investigated during the program. Composite-Hybrid unison rings for variable stator vanes have been found to be another innovative technology for compressors of modern Aero engines. Composite-Hybrid Technology has been adopted for unison rings and demonstrated in rig tests. The weight and cost reductions have been demonstrated. Both technologies have been demonstrated successfully in a core demonstrator. (orig.) [German] Im Rahmen des Luftfahrtforschungs- und -technologieprogramms 'Engine 3E' (Environment, Economy and Efficiency) der Bundesregierung wurde bei der Rolls Royce Deutschland GmbH auf dem Gebiet der Verdichterbauweisen die Technologie zur Auslegung und Herstellung integraler Schaufel-Scheiben (BLade Integrated DiSK - BLISK-) entwickelt und getestet. Diese Technologie bietet das Potential, das Gewicht der Scheiben um bis zu 30% zu reduzieren. Unter Einsatz moderner Fertigungsstrategien bieten integrale Schaufel-Scheiben in ausgewaehlten Einsatzbereichen zusaetzlich Potential fuer bis zu 10% Kostenreduktion. Bei der Betrachtung der Kosten muessen neben den Herstellungskosten auch die gesamten waehrend des Einsatzes des Triebwerkes entstehenden Kosten beruecksichtigt werden. Die Blisktechnologie kann deshalb nur erfolgreich in zivilen Triebwerken eingesetzt werden, wenn Schaeden oekonomisch repariert werden koennen. Als weiterer

  8. Chemical composition of the volatile oil from flowers and leaves of new Passiflora hybrids

    Directory of Open Access Journals (Sweden)

    Jacopo Calevo

    2016-10-01

    Full Text Available Summary. Passiflora is a genus of the Passifloraceae family with more than five hundred species, which are known for their edible fruits, their therapeutic properties and ornamental purposes, and they are very attractive both for the horticultural sector as well as for the herbal and pharmaceutical industry. A detailed chemical composition of Passiflora essential oil has been reported only for few main species (e.g. P. edulis Sims and P. incarnata L.. In this article we evaluated for the first time the essential oil composition of three Passiflora ornamental hybrids, exploring fresh flowers and leaves by GC/FID and GC/MS. Several compounds were identified, with a peculiar distribution in the hybrids: benzyl alcohol (7.6%, geraniol (13.7%, phytol (14,3%, eugenol (3.9%, 2-phenylethanol (4.7%, cis-3-hexenal (2.8% and palmitic acid (2% were the main compounds of the essential oil of fresh leaves of the hybrid P. ‘FSO-040711’; the highest percentages of benzyl alcohol (12.2% and 2-phenylethanol (13.6% were found in fresh flowers of P. ‘FSO-130913’ and  the highest amount of phytol (38.5% was present in the fresh leaves of P. ‘FSO-080415’. Eugenol (5.3% seems to be related to the typical honey/vanilla fragrance of the flowers of P. ‘FSO-040711’. Industrial relevance. The main bulk of constituents of the volatile fractions of Passiflora hybrids were found to be hydrocarbons and alcohols, while terpens and aldehydes occurred in lower amount. We are currently focus on investigating the biological activity of the Passiflora oil extracts for perfumery and cosmetic industry. Keywords. Maracuja; interspecific hybrids; essential oil; gas chromatography

  9. The concept of a novel hybrid smart composite reinforced with radially aligned zigzag carbon nanotubes on piezoelectric fibers

    Science.gov (United States)

    Ray, M. C.

    2010-03-01

    A new hybrid piezoelectric composite (HPZC) reinforced with zigzag single-walled carbon nanotubes (CNTs) and piezoelectric fibers is proposed. The novel constructional feature of this composite is that the uniformly aligned CNTs are radially grown on the surface of piezoelectric fibers. A micromechanics model is derived to estimate the effective piezoelectric and elastic properties. It is found that the effective piezoelectric coefficient e31 of the proposed HPZC, which accounts for the in-plane actuation, is significantly higher than that of the existing 1-3 piezoelectric composite without reinforcement with carbon nanotubes and the previously reported hybrid piezoelectric composite (Ray and Batra 2009 ASME J. Appl. Mech. 76 034503).

  10. Effect of winding layer and speed on kenaf/glass fiber hybrid reinforced acrylonitrile butadiene styrene (ABS) composites

    Science.gov (United States)

    Khoni, Norizzahthul Ainaa Abdul; Sharifah Shahnaz S., B.; Ghazali, Che Mohd Ruzaidi

    2016-07-01

    The usage of natural fiber is becoming significant in composite industries due to their good performance. Single and continuous natural fibers have relatively high mechanical properties; especially their young modulus can be as high as glass fibers. Filament winding is a method to produce technically aligned composites which have high fibers content. The properties of filament winding can be tailored to meet the end product requirements. This research studied the compression properties of kenaf/glass fibers hybrid reinforced composites. Kenaf/glass fibers hybrid composite samples were fabricated by filament winding technique and their properties were compared with the properties of neat kenaf fiber and glass fibers composites. The kenaf/glass fiber hybrid composites exhibited higher strength compared to the neat glass fibers composites. Composites of helical pattern, which produced at low winding speed showed better compression resistance than hoop pattern winding, which produced at high winding speed. As predicted, kenaf composite showed highest water absorption; followed by kenaf/glass fiber hybrid composites while neat glass fiber has lowest water absorption capability.

  11. Effects of biomass type, blend composition, and co-pyrolysis temperature on hybrid coal quality

    Science.gov (United States)

    Sasongko, Dwiwahju; Wulandari, Winny; Rubani, Inga Shaffira; Rusydiansyah, Rifqi

    2017-01-01

    An experimental study on co-pyrolysis of coal with biomass wastes to produce hybrid coal was conducted to investigate the effects of important process variables, namely biomass type (rice husk and sawdust), blend composition, and co-pyrolysis temperature on the quality of hybrid coal. The experiments were carried out using a vertical tubular furnace equipped with temperature controller to maintain the co-pyrolysis reactor at a given temperature. Nitrogen gas was introduced into the furnace to create an inert environment preventing the sample from burning. A known mass of solid sample consisting of manually granulated blend of coal and biomass with binder in spherical shape was contained in a basket made of stainless sieve. After a given residence time, the sample was taken from the furnace. The blend sample prior to experiment and the produced hybrid coal were then characterized for its proximate analysis, ultimate analysis and calorific value. Experimental findings suggested that by increasing co-pyrolysis temperature from 200 to 400 °C, the calorific value of hybrid coal will increase by 14.5-17.7% to be 5585-7060 kcal/kg. It was also showed that 30% increase in the biomass content in the fuel blend would produce a hybrid coal that emitting up to 25.9% less in CO2 when used for combustion, although its calorific value decreased down to 8% compared to the biomass blend. It is shown that hybrid coal obtained from this study is comparable in calorific value to bituminous coal, thus suitable for power plant while being more environmentally friendly.

  12. IJER@2014 Page 21 Prediction of Mechanical Properties of Hybrid Fiber Reinforced Polymer Composites

    Directory of Open Access Journals (Sweden)

    P Sivaraj

    2014-03-01

    Full Text Available Abstract— This work presents a systematic approach to evaluate and study the effect of process parameters on tensile flexural and impact strength of coir and bagasse fiber reinforced polyester-based hybrid composites and also predicts the properties of random oriented hybrid composites. The composite panel was fabricated using hand lay-up method to the size of 300mmx200mmx3mm with various weight percentage of natural fibers namely coir (10, 20 and 30 wt % and bagasse (10, 20 and 30 wt % combined with polyester resin. The mechanical properties testing such as tensile, flexural and impact strength were carried out for the samples cut from the fabricated composite panel to the dimensions as per ASTM standard. The significant contribution of mixing of fiber was determined by analysis of variance. The second-order polynomial curve fitting equations are modelled to predict the mechanical properties such as tensile, flexural and impact strength. Also scanning electron microscopy testing was conducted on tensile test specimen to find the fiber matrix interfacial adhesion.

  13. Ballistic Impact Response of Woven Hybrid Coir/Kevlar Laminated Composites

    Directory of Open Access Journals (Sweden)

    Azrin Hani A.R

    2016-01-01

    Full Text Available The effects of different laminated hybrid composites stacking configuration subjected to ballistic impact were investigated. The hybrid composites consist of woven coir (C and woven Kevlar (K layers laminated together. The samples of woven coir were prepared using handloom device. The composites were produced by stacking the laminated woven coir and Kevlar alternately with the presence of the binder. The samples were tested under ballistic impact with different stacking configuration. The results obtained had successfully achieved the National Institute of Justice (NIJ standard level IIA with energy absorption of 435.6 kJ and 412.2 kJ under the projectile speed of between 330 m/s and 321 m/s respectively. Samples that having Kevlar layer at the front face and woven coir layer as back face achieved partial penetration during projectile impact. This orientation is proven to have good impact energy absorption and able to stop projectile at the second panel of the composites.

  14. Impact Strength and Flexural Properties Enhancement of Methacrylate Silane Treated Oil Palm Mesocarp Fiber Reinforced Biodegradable Hybrid Composites

    OpenAIRE

    Chern Chiet Eng; Nor Azowa Ibrahim; Norhazlin Zainuddin; Hidayah Ariffin; Wan Md Zin Wan Yunus

    2014-01-01

    Natural fiber as reinforcement filler in polymer composites is an attractive approach due to being fully biodegradable and cheap. However, incompatibility between hydrophilic natural fiber and hydrophobic polymer matrix restricts the application. The current studies focus on the effects of incorporation of silane treated OPMF into polylactic acid (PLA)/polycaprolactone (PCL)/nanoclay/OPMF hybrid composites. The composites were prepared by melt blending technique and characterize the composite...

  15. A Randomized 10-year Prospective Follow-up of Class II Nanohybrid and Conventional Hybrid Resin Composite Restorations

    DEFF Research Database (Denmark)

    van Dijken, Jan Wv; Pallesen, Ulla

    2014-01-01

    Purpose: To evaluate the 10-year durability of a nanohybrid resin composite in Class II restorations in a randomized controlled intraindividual comparison with its conventional hybrid resin composite predecessor. Materials and Methods: Each of 52 participants received at least two Class II...... restorations that were as similar as possible. The cavities were chosen at random to be restored with a nanohybrid resin composite (Excite/Tetric EvoCeram (TEC); n = 61) and a conventional hybrid (Excite/Tetric Ceram (TC); n = 61). The restorations were evaluated with slightly modified USPHS criteria...... investigated resin composites. Conclusion: The nanohybrid and the conventional hybrid resin composite showed good clinical effectiveness in extensive Class II restorations during the 10-year study....

  16. Insect damages on structural, morphologic and composition of Bt maize hybrids to silage

    Directory of Open Access Journals (Sweden)

    Geraldo Balieiro Neto

    2013-03-01

    Full Text Available It was aimed to evaluate the effect of insect damage on the morphologic and structural characteristics and chemical composition from maize hybrids DKB 390 and AG 8088 with the Cry1Ab trait versus its nonbiotech counterpart. The GMO did not receive insecticide application and the conventional hybrids received one deltametrina (2.8% application at 42 days. The damages caused bySpodoptera frugiperda and Helicoverpa zea in hybrids with Cry1Ab were smaller than its nonbiotech counterpart. After harvest, 95 days after seedling plants were separated in stalks, ears, leafs, dead leafs and floral pennant. The experimental design was randomized block in factorial arrangement 2 x 2. The height of plant and height of ear, percentage and amount of dead leafs from hybrids with the Cry1Ab were higher than its nonbiotech counterpart. There was higher nutrients transfer from stalks to grain filling and smaller rate stalks:ear on transgenic plant. The quality of the transgenic plants can be better when harvest earlier, by increasing no fiber carbohydrates, but when harvest latter, by increasing stalk percentage and stalk lignin content.

  17. Fracture Toughness of Nanohybrid and Hybrid Composites Stored Wet and Dry up to 60 Days

    Directory of Open Access Journals (Sweden)

    Sookhakiyan M

    2017-03-01

    Full Text Available Statement of Problem: Patients’ demand for tooth-colored restoratives in the posterior region is increasing. Clinicians use universal nanohybrid resin composites for both anterior and posterior regions. There are few published reports comparing fracture toughness of nonohybrids and that of hybrid composite stored wet and dry. Objectives: To investigate the fracture toughness of three nanohybrids compared to that of a hybrid resin composite stored dry or wet up to 60 days, using four- point bending test. Materials and Methods: Four resin composites were used: three nanohybrids; Filtek Supreme (3M, Ice (SDI, TPH3 (Dentsply and one hybrid Filtek P60 (3M. For each material, 40 rectangular notched beam specimens were prepared with dimensions of 30 mm × 5mm × 2mm. The specimens were randomly divided into 4 groups (n = 10 and stored at 37ºC either in distilled water or dry for 1 and 60 days. The specimens were placed on the four-point test jig and subjected to force (N using universal testing machine loaded at a crosshead speed of 0.5mm/min and maximum load at specimen failure was recorded and KIc was calculated. Results: Three-way ANOVA showed a significant interaction between all the factors (all p < .0001. Except for TPH3, all tested materials showed significantly higher KIc when stored dry than stored wet (p < 0.05. After 1 day of dry storage, Ice showed the highest KIc (2.04 ± 0.32 followed by Filtek P60 and the lowest was for Filtek Supreme (1.39 ± 0.13. The effect of time on fracture toughness was material dependent. Conclusions: Wet storage adversely affected the fracture toughness of almost all materials. Keeping the restoration dry in the mouth may increase their fracture toughness. Therefore, using a coating agent on the surface of restoration may protect them from early water uptake and increase their strength during a time period.

  18. Preparation and mechanical properties of TLCP/UP/GF in-situ hybrid composites

    Institute of Scientific and Technical Information of China (English)

    YU Xian-bao; WEI Chun; LU Shao-rong; YU Jing-hong; XU Deng; LU Chi-hua

    2006-01-01

    One kind of novel reactive thermotropic liquid crystalline polymer-methacryloyl copolymer (LCMC) containing polyester mesogenic units was synthesized. Its structure,morphology and properties were investigated systemically by Ubbelohde viscometer,differential scanning calorimetry (DSC),Fourier transform infrared spectroscopy (FTIR),wide-angle X-ray diffractometry (WAXD) and polarizing optical microscopy (POM). The results indicate that it is one kind of nematic thermotropic liquid crystal polymer (TLCP). The impact strength,bending strength and the morphologies of impact fracture surface of LCMC,unsaturated polyester (UP) and glass fiber (GF) in-situ hybrid composites were studied by Izod impact tester,universal testing machine and scanning electron microscopy (SEM),respectively. The results show that the impact and bending strength of composites containing LCMC are improved,especially the composites containing 5% LCMC increases most obviously. These results with SEM results reveal that LCMC plays an important role in the improvement of interfacial adhesive between matrix and fiber.

  19. Cathodoluminescence characterization of polystyrene-BaZrO3 hybrid composites

    Science.gov (United States)

    Savchyn, V. P.; Popov, A. I.; Aksimentyeva, O. I.; Klym, H.; Horbenko, Yu. Yu.; Serga, V.; Moskina, A.; Karbovnyk, I.

    2016-07-01

    The radiation properties and the electronic structure of hybrid composites based on suspension polystyrene (PS) and nanocrystals of BaZrO3 (BZO) (d < 50 nm) have been studied using luminescent spectroscopy and x-ray analysis. A strong cathodoluminescence (CL) in BZO-nanocrystals is observed in temperature range 80-293 K. It is modified in BZO-PS composites: both the low- and a high-energy bands (near 4 eV) appear, together with a significant reduction in the CL intensity. A decrease of the lattice parameter a for BZO phase in the composite and the modification of CL spectra indicate for changes in the nanocrystalline structure induced by the polymer.

  20. Finite-Element Analysis of Jute- and Coir-Fiber-Reinforced Hybrid Composite Multipanel Plates

    Science.gov (United States)

    Nirbhay, M.; Misra, R. K.; Dixit, A.

    2015-09-01

    Natural-fiber-reinforced polymer composite materials are rapidly gaining interest worldwide both in terms of research and industrial applications. The present work includes the characterization and modeling of jute- and coir-fiber-reinforced hybrid composite materials. The mechanical behavior of a two-panel plate and a sixpanel box structure is analyzed under various loading regimes by using the finite-element software ABAQUS®. Exhaustive parametric studies are also performed to obtain a clear insight into the relationships between various parameters and deflections of the panels and stress distributions in them. Deflections of both the structures are compared and found to be in good agreement with published results. To determine the mechanical behavior of natural-fiber-reinforced composite panels, a finite-element analysis is performed.

  1. Pseudo-elastic Hysteresis Damping Characteristics of SMA Hybrid Composite Lamina

    Institute of Scientific and Technical Information of China (English)

    SUN Shuangshuang; JIANG Xiance; SUN Guojun

    2008-01-01

    The longitudinal mechanical behavior of shape memory alloy (SMA) composite lamina subjected to longitudinally strain or stress controlled cyclic loading is investigated. The SMA is under pseudo-elastic condition and the fibers are embedded (bonded) to the host material. The influences of temperature, volume fraction of SMA and longitudinal modulus of the host material on the stress-strain relation and energy dissipation of the SMA hybrid composite lamina are discussed. The results indicate that the stress-strain curve of the lamina per cycle shows a hysteresis loop. The hysteresis damping decreases with increasing temperature and with decreasing volume fractions of SMA. In addition, the hysteresis damping is nearly independent of the longitudinal modulus of the host material under strain controlled loading. However, it depends dramatically on the longitudinal modulus of the host material under stress controlled loading, which shows the SMA composite lamina has high pseudo-elastic hysteresis damping when the longitudinal modulus of the host material is low.

  2. Synthesis and Characterization of the Graphene-Fe3O4 Hybrid Composite.

    Science.gov (United States)

    Myekhlai, Munkhshur; Lee, Taejin; Lee, Sinil; Kim, Junhyo; Kang, Donghoon; Noh, Jungpil; Huh, Sunchul; Chung, Hanshik; Jeong, Hyomin

    2015-03-01

    Graphene and iron oxide composites have attracted huge attention in the fields of nanoelectronics and nanodevices due to their superior magnetic and electric characteristics. However, their synthesis methods are composed of many steps and use toxic chemical reactants. Accordingly, in this study, a GN-Fe3O4 NP hybrid composite was prepared using an eco-friendly and facile method. Its morphological and structural characteristics were then investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffractometer and UV-visible spectroscopy. The results indicated that the GN structures as well as Fe3O4 NPs were significantly associated with the composite of GN-Fe3O4 NPs.

  3. Influence of Stacking Sequence on the Impact and Postimpact Bending Behavior of Hybrid Sandwich Composites

    Science.gov (United States)

    Özen, M.

    2017-01-01

    A new hybrid sandwich structure was developed by using carbon, e-glass, and s-glass fabrics as reinforcement materials, an epoxy resin as the matrix material for face sheets, and a PVC foam as the core material. Six different configurations were prepared. Sandwich composites plates with different stacking sequences were subjected to low-speed impacts will energies of 7.5, 15, and 22.5 J. Their impact response is analyzed and reported in terms of the peak load as a function of impact energy. After impact tests, 3-point bending tests were conducted to determine the bending behavior of the sandwich composites after impacts in terms of their flexural strength. The results obtained showed that the use of carbon fabrics in the face sheets increased the peak loads for all the impact energies considered. The presence of carbon fibers in skin regions increased the flexural strength of the composites, but e-glass fibers decreased this strength.

  4. The Electrical Properties of Hybrid Composites Based on Multiwall Carbon Nanotubes with Graphite Nanoplatelets

    Science.gov (United States)

    Perets, Yulia; Aleksandrovych, Lyudmila; Melnychenko, Mykola; Lazarenko, Oleksandra; Vovchenko, Lyudmila; Matzui, Lyudmila

    2017-06-01

    In the present work, we have investigated the concentration dependences of electrical conductivity of monopolymer composites with graphite nanoplatelets or multiwall carbon nanotubes and hybrid composites with both multiwall carbon nanotubes and graphite nanoplatelets. The latter filler was added to given systems in content of 0.24 vol%. The content of multiwall carbon nanotubes is varied from 0.03 to 4 vol%. Before incorporation into the epoxy resin, the graphite nanoplatelets were subjected to ultraviolet ozone treatment for 20 min. It was found that the addition of nanocarbon to the low-viscosity suspension (polymer, acetone, hardener) results in formation of two percolation transitions. The percolation transition of the composites based on carbon nanotubes is the lowest (0.13 vol%).

  5. Influence of light-polymerization modes on the degree of conversion and mechanical properties of resin composites: a comparative analysis between a hybrid and a nanofilled composite.

    Science.gov (United States)

    da Silva, Eduardo Moreira; Poskus, Laiza Tatiana; Guimarães, José Guilherme Antunes

    2008-01-01

    This study analyzed the influence of the light polymerization mode on the degree of conversion (DC) and mechanical properties of two resin composites: a hybrid (Filtek P60) and a nanofilled composite (Filtek Supreme). The composites were light activated by three light polymerization modes (Standard-S: 650 mW/cm2 for 30 seconds; High intensity-H: 1000 mW/cm2 for 20 seconds and Gradual-G: 100 up to 1000 mW/cm2 for 10 seconds + 1000 mW/cm2 for 10 seconds). The DC (%) was measured by FT-Raman spectroscopy. Flexural strength and flexural modulus were obtained from bar-shaped specimens (1 x 2 x 10 mm) submitted to the three-point bending test. Microhardness was evaluated by Knoop indentation (KHN). Data were analyzed by ANOVA and Student-Newman-Keuls multiple range test and linear regression analysis. The results showed the following DC: H > S > G (p hybrid > nanofilled (p S = G (p hybrid composite presented higher flexural strength and flexural modulus than the nanofilled composite (p composites (p = 0.1605). The results suggest that nanofilled composites may present a lower degree of conversion and reduced mechanical properties compared to hybrid composites.

  6. Featureless quantum insulator on the honeycomb lattice

    Science.gov (United States)

    Kim, Panjin; Lee, Hyunyong; Jiang, Shenghan; Ware, Brayden; Jian, Chao-Ming; Zaletel, Michael; Han, Jung Hoon; Ran, Ying

    2016-08-01

    We show how to construct fully symmetric states without topological order on a honeycomb lattice for S =1/2 spins using the language of projected entangled pair states. An explicit example is given for the virtual bond dimension D =4 . Four distinct classes differing by lattice quantum numbers are found by applying the systematic classification scheme introduced by two of the authors [S. Jiang and Y. Ran, Phys. Rev. B 92, 104414 (2015), 10.1103/PhysRevB.92.104414]. Lack of topological degeneracy or other conventional forms of symmetry breaking in the proposed wave functions are checked by numerical calculations of the entanglement entropy and various correlation functions. Exponential decay of all correlation functions measured are strongly indicative of the energy gap for the putative parent Hamiltonian of the state. Our work provides the first explicit realization of a featureless quantum state for spin-1/2 particles on a honeycomb lattice.

  7. Traffic gridlock on a honeycomb city

    CERN Document Server

    Olmos, L E

    2016-01-01

    As a clear signature of modern urban design concepts, urban street networks in dense populated zones are evolving nowadays towards grid-like layouts with rectangular shapes, and most studies on traffic flow assume street networks as square lattices. However, ideas from forgotten design schools bring unexplored alternatives that might improve traffic flow in many circumstances. Inspired on an old and almost in oblivion urban plan, we report the behavior of the Biham-Middleton-Levine model (BML) \\-- a paradigm for studying phase transitions of traffic flow \\-- on a hypothetical city with a perfect honeycomb street network. In contrast with the original BML model on a square lattice, the same model on a honeycomb does not show any anisotropy or intermediate states, but a single continuous phase transition between free and totally congested flow, a transition that can be completely characterized by the tools of classical percolation. Although the transition occurs at a lower density than for the conventional BML,...

  8. Hydrogen storage behaviors of Ni-doped graphene Oxide/MIL-101 hybrid composites.

    Science.gov (United States)

    Lee, Seul-Yi; Park, Soo-Jin

    2013-01-01

    In this work, Ni-doped graphene oxide/MIL-101 hybrid composites (Ni--GO/MIL) were prepared to investigate their hydrogen storage behaviors. Ni--GO/MIL was synthesized by adding Ni--GO in situ during the synthesis of MIL-101 using a hydrothermal process, which was conducted by conventional convection heating with Cr(III) ion as a metal center and telephthalic acid as organic ligands. The crystalline structures and morphologies were measured by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The specific surface area and micropore volume were investigated by N2/77 K adsorption isotherms using the Brunauer-Emmett-Teller (BET) method and Dubinin-Radushkevic (D-R) equation, respectively. The hydrogen storage capacity was investigated by BEL-HP at 77 K and 1 bar. The obtained results show that Ni--GO/MIL presents new directions for achieving novel hybrid materials with higher hydrogen storage capacity.

  9. A hybrid method based upon nonlinear Lamb wave response for locating a delamination in composite laminates.

    Science.gov (United States)

    Yelve, Nitesh P; Mitra, Mira; Mujumdar, P M; Ramadas, C

    2016-08-01

    A new hybrid method based upon nonlinear Lamb wave response in time and frequency domains is introduced to locate a delamination in composite laminates. In Lamb wave based nonlinear method, the presence of damage is shown by the appearance of higher harmonics in the Lamb wave response. The proposed method not only uses this spectral information but also the corresponding temporal response data, for locating the delamination. Thus, the method is termed as a hybrid method. The paper includes formulation of the method and its application to locate a Barely Visible Impact Damage (BVID) induced delamination in a Carbon Fiber Reinforced Polymer (CFRP) laminate. The method gives the damage location fairly well. It is a baseline free method, as it does not need data from the pristine specimen.

  10. Projected equations of motion approach to hybrid quantum/classical dynamics in dielectric-metal composites

    CERN Document Server

    McMillan, Ryan J; Grüning, Myrta

    2016-01-01

    We introduce a hybrid method for dielectric-metal composites that describes the dynamics of the metallic system classically whilst retaining a quantum description of the dielectric. The time-dependent dipole moment of the classical system is mimicked by the introduction of projected equations of motion (PEOM) and the coupling between the two systems is achieved through an effective dipole-dipole interaction. To benchmark this method, we model a test system (semiconducting quantum dot-metal nanoparticle hybrid). We begin by examining the energy absorption rate, showing agreement between the PEOM method and the analytical rotating wave approximation (RWA) solution. We then investigate population inversion and show that the PEOM method provides an accurate model for the interaction under ultrashort pulse excitation where the traditional RWA breaks down.

  11. SimConcept: a hybrid approach for simplifying composite named entities in biomedical text.

    Science.gov (United States)

    Wei, Chih-Hsuan; Leaman, Robert; Lu, Zhiyong

    2015-07-01

    One particular challenge in biomedical named entity recognition (NER) and normalization is the identification and resolution of composite named entities, where a single span refers to more than one concept (e.g., BRCA1/2). Previous NER and normalization studies have either ignored composite mentions, used simple ad hoc rules, or only handled coordination ellipsis, making a robust approach for handling multitype composite mentions greatly needed. To this end, we propose a hybrid method integrating a machine-learning model with a pattern identification strategy to identify the individual components of each composite mention. Our method, which we have named SimConcept, is the first to systematically handle many types of composite mentions. The technique achieves high performance in identifying and resolving composite mentions for three key biological entities: genes (90.42% in F-measure), diseases (86.47% in F-measure), and chemicals (86.05% in F-measure). Furthermore, our results show that using our SimConcept method can subsequently improve the performance of gene and disease concept recognition and normalization. SimConcept is available for download at: http://www.ncbi.nlm.nih.gov/CBBresearch/Lu/Demo/SimConcept/.

  12. Numerical Homogenization of Protective Ceramic Composite Layers using the Hybrid Finite-Discrete Element Methods

    Directory of Open Access Journals (Sweden)

    Zainorizuan Mohd Jaini

    2013-12-01

    Full Text Available Innovative technologies have resulted in more effective ceramic composite as high rate loading-resistance and protective layer. The ceramic composite layer consists of ceramic frontal plate that bonded by softer-strong reinforced polymer network, consequently gains the heterogeneous condition. These materials serve specific purposes of defeating high rate loading and maintaining the structural integrity of the layer. Further due to the lack of a constituent material and tedious problem in heterogonous material modelling, a numerical homogenization is employed to analyse the isotropic material properties of ceramic composite layer in homogenous manner. The objective of this study is to derive a constitutive law of the ceramic composite using the multi-scale analysis. Two-dimensional symmetric macrostructure of the ceramic composite was numerically modelled using the hybrid finite-discrete element method to investigate the effective material properties and strength profile. The macrostructure was modelled as brittle material with nonlinear material properties. The finite element method is incorporated with a Rankine-Rotating Crack approach and discrete element to model the fracture onset. The prescribed uniaxial and biaxial loadings were imposed along the free boundaries to create different deformations. Due to crack initiation on the macrostructure, the averaged stresses were calculated to plot the stress-strain curves and the effective yield stress surface. From the multi-scale analysis, the rate-dependency of Mohr-Coulomb constitutive law was derived for the ceramic composite layer.

  13. SimConcept: A Hybrid Approach for Simplifying Composite Named Entities in Biomedicine.

    Science.gov (United States)

    Wei, Chih-Hsuan; Leaman, Robert; Lu, Zhiyong

    Many text-mining studies have focused on the issue of named entity recognition and normalization, especially in the field of biomedical natural language processing. However, entity recognition is a complicated and difficult task in biomedical text. One particular challenge is to identify and resolve composite named entities, where a single span refers to more than one concept(e.g., BRCA1/2). Most bioconcept recognition and normalization studies have either ignored this issue, used simple ad-hoc rules, or only handled coordination ellipsis, which is only one of the many types of composite mentions studied in this work. No systematic methods for simplifying composite mentions have been previously reported, making a robust approach greatly needed. To this end, we propose a hybrid approach by integrating a machine learning model with a pattern identification strategy to identify the antecedent and conjuncts regions of a concept mention, and then reassemble the composite mention using those identified regions. Our method, which we have named SimConcept, is the first method to systematically handle most types of composite mentions. Our method achieves high performance in identifying and resolving composite mentions for three fundamental biological entities: genes (89.29% in F-measure), diseases (85.52% in F-measure) and chemicals (84.04% in F-measure). Furthermore, our results show that, using our SimConcept method can subsequently help improve the performance of gene and disease concept recognition and normalization.

  14. Effect of weathering on the properties of hybrid composite based on polyethylene, woodflour, and nanoclay

    Directory of Open Access Journals (Sweden)

    Amir Eshraghi

    2013-02-01

    Full Text Available Hybrid composites of polyethylene/wood flour/nanoclay with different concentrations of nanoclay were fabricated using melt compounding followed by injection molding. Composites were weathered in a xenon-arc type accelerated weathering apparatus for 2000 h. Physical properties of the composites were evaluated by colorimetery and water absorption before and after weathering. Changes in surface chemistry were monitored using spectroscopic techniques. The results indicated that water absorption of the composites increased after weathering, but nanoclay can reduce the intensity of weathering to some extent by decreasing water absorption. Weathering increased the degree of color change and lightness of the samples; however, the lightness of the samples containing nanoclay was less than that of neat wood-plastic composites. Fourier transform infrared spectroscopy revealed a lower carbonyl index of composites containing nanoclay. X-ray diffraction patterns revealed that the nanocomposites formed were intercalated. The order of intercalation for samples containing 2 wt% nanoclay was higher than that of 4 wt% at the same maleic anhydride grafted polyethylene content, due to some agglomeration of the nanoclay.

  15. Hybrid carbon-glass fiber/toughened epoxy thick composites subject to drop-weight and ballistic impacts

    Science.gov (United States)

    Sevkat, Ercan

    The goals of this study are to investigate the low velocity and ballistic impact response of thick-section hybrid fiber composites at room temperature. Plain-woven S2-Glass and IM7 Graphite fabrics are chosen as fiber materials reinforcing the SC-79 epoxy. Four different types of composites consisting of alternating layers of glass and graphite woven fabric sheets are considered. Tensile tests are conducted using 98 KN (22 kip) MTS testing machine equipped with environmental chamber. Low-velocity impact tests are conducted using an Instron-Dynatup 8250 impact test machine equipped with an environmental chamber. Ballistic impact tests are performed using helium pressured high-speed gas-gun. Tensile tests results were used to define the material behavior of the hybrid and non-hybrid composites in Finite Element modeling. The low velocity and ballistic impact tests showed that hybrid composites performance was somewhere between non-hybrid woven composites. Using woven glass fabrics as outer skin improved the impact performance of woven graphite composite. However hybrid composites are prone to delamination especially between dissimilar layers. The ballistic limit velocity V50 hybrid composites were higher that of woven graphite composite and lower than that of woven glass composite. Both destructive cross-sectional micrographs and nondestructive ultrasonic techniques are used to evaluate the damage created by impact. The Finite Element code LS-DYNA is chosen to perform numerical simulations of low velocity and ballistic impact on thick-section hybrid composites. The damage progression in these composites shows anisotropic nonlinearity. The material model to describe this behavior is not available in LS-DYNA material library. Initially, linear orthotropic material with damage (Chan-Chan Model) is employed to simulate some of the experimental results. Then, user-defined material subroutine is incorporated into LS-DYNA to simulate the nonlinear behavior. The

  16. Porous-core honeycomb bandgap THz fiber

    DEFF Research Database (Denmark)

    Nielsen, Kristian; Rasmussen, Henrik K.; Jepsen, Peter Uhd

    2011-01-01

    In this Letter we propose a novel (to our knowledge) porous-core honeycomb bandgap design. The holes of the porous core are the same size as the holes in the surrounding cladding, thereby giving the proposed fiber important manufacturing benefits. The fiber is shown to have a 0:35-THz......-wide fundamental bandgap centered at 1:05 THz. The calculated minimum loss of the fiber is 0:25 dB=cm....

  17. Pretransitional Clusters in Multicolor Liquid Crystalline Honeycombs

    Science.gov (United States)

    Ungar, Goran; Zeng, Xiangbing; Liu, Feng; Kieffer, Robert; Nürnberger, Constance; Tschierske, Carsten; Gehring, Gillian

    2012-02-01

    X-shaped tetraphilic molecules consisting of a rod-like core with two hydrogen-bonding terminal groups and two mutually incompatible side-chains A and B form a range of honeycomb-like structures in which the rods act as bricks in the walls of polygonal cylinder cells containing the fluid side-chains. Some of these systems exhibit a 2nd-order transition from the high-temperature mixed (``1-color'') phase to a low-temperature phase in which the side-chains are separated in A and B cells (``2-color''). This is the situation with triangular, rectangular and square honeycombs. Strong pre-transitional 2-color domains formation is observed above the transition temperature. Particularly interesting is the case of the hexagonal honeycomb, where no fully phase-separated ground state can exist. Here the 2-color ``ordered'' phase consists of [A] cells and [A(1/4)B(3/4)] cells. The situation is similar to frustrated ferro- and antiferromagnets on a kagome lattice. Instead of the spins flipping, it is the molecules that undergo 180 degree rotations about the axis of their rod-like cores [Science 331, 1302 (2011)].

  18. High-precision CTE measurement of hybrid C/SiC composite for cryogenic space telescopes

    CERN Document Server

    Enya, K; Imai, T; Tange, Y; Kaneda, H; Katayama, H; Kotani, M; Maruyama, K; Naitoh, M; Nakagawa, T; Onaka, T; Suganuma, M; Ozaki, T; Kume, M; Krodel, M R

    2011-01-01

    This paper presents highly precise measurements of thermal expansion of a "hybrid" carbon-fiber reinforced silicon carbide composite, HB-Cesic\\textregistered - a trademark of ECM, in the temperature region of \\sim310-10K. Whilst C/SiC composites have been considered to be promising for the mirrors and other structures of space-borne cryogenic telescopes, the anisotropic thermal expansion has been a potential disadvantage of this material. HB-Cesic\\textregistered is a newly developed composite using a mixture of different types of chopped, short carbon-fiber, in which one of the important aims of the development was to reduce the anisotropy. The measurements indicate that the anisotropy was much reduced down to 4% as a result of hybridization. The thermal expansion data obtained are presented as functions of temperature using eighth-order polynomials separately for the horizontal (XY-) and vertical (Z-) directions of the fabrication process. The average CTEs and their dispersion (1{\\sigma}) in the range 293-10...

  19. Hybrid carbon fiber/carbon nanotube composites for structural damping applications

    Science.gov (United States)

    Tehrani, M.; Safdari, M.; Boroujeni, A. Y.; Razavi, Z.; Case, S. W.; Dahmen, K.; Garmestani, H.; Al-Haik, M. S.

    2013-04-01

    Carbon nanotubes (CNTs) were grown on the surface of carbon fibers utilizing a relatively low temperature synthesis technique; graphitic structures by design (GSD). To probe the effects of the synthesis protocols on the mechanical properties, other samples with surface grown CNTs were prepared using catalytic chemical vapor deposition (CCVD). The woven graphite fabrics were thermally shielded with a thin film of SiO2 and CNTs were grown on top of this film. Raman spectroscopy and electron microscopy revealed the grown species to be multi-walled carbon nanotubes (MWCNTs). The damping performance of the hybrid CNT-carbon fiber-reinforced epoxy composite was examined using dynamic mechanical analysis (DMA). Mechanical testing confirmed that the degradations in the strength and stiffness as a result of the GSD process are far less than those encountered through using the CCVD technique and yet are negligible compared to the reference samples. The DMA results indicated that, despite the minimal degradation in the storage modulus, the loss tangent (damping) for the hybrid composites utilizing GSD-grown MWCNTs improved by 56% compared to the reference samples (based on raw carbon fibers with no surface treatment or surface grown carbon nanotubes) over the frequency range 1-60 Hz. These results indicated that the energy dissipation in the GSD-grown MWCNTs composite can be primarily attributed to the frictional sliding at the nanotube/epoxy interface and to a lesser extent to the stiff thermal shielding SiO2 film on the fiber/matrix interface.

  20. Effect of different polishing systems on the surface roughness of nano-hybrid composites

    Directory of Open Access Journals (Sweden)

    Brijesh Patel

    2016-01-01

    Full Text Available Objective: The study aimed to investigate the influence of different polishing systems on the surface roughness of nano-hybrid composite resins. Background: Different shapes of polishing systems are available according to the site of work. To minimize variability, a new system with single shape is developed that can be utilized in both anterior as well as posterior teeth. Materials and Methods: Seventy composite discs were fabricated using Teflon well (10 mm × 3 mm. Two main group of nano-hybrid composite Group I - Filtek Z350 and Group II - Tetric N-Ceram were used (n = 35 for each group. Both groups were further divided into four subgroups. Subgroup a - OneGloss (n = 10, Subgroup b - PoGo (n = 10, Subgroup c - Sof-Lex spiral (n = 10, Subgroup d - Mylar strip (control, n = 5. Samples were polished according to the manufacturer′s recommendations. Surface roughness test was performed using contact profilometer. The obtained data were analyzed using the one-way analysis of variance test. Result: Tetric N-Ceram produced smoother surfaces than Filtek Z350 (P < 0.05. Mylar strip and "PoGo" created equally smooth surfaces, while significantly rougher surfaces were obtained after applications of "Sof-Lex spiral" and "OneGloss" (P < 0.05. Conclusion: Polishing ability of Tetric N-Ceram is better than Filtek Z350 XT. "PoGo" seems to be a better polishing system than "OneGloss" and "Sof-Lex Spiral."

  1. Synergetic Effects of Mechanical Properties on Graphene Nanoplatelet and Multiwalled Carbon Nanotube Hybrids Reinforced Epoxy/Carbon Fiber Composites

    OpenAIRE

    Pin-Ning Wang; Tsung-Han Hsieh; Chin-Lung Chiang; Ming-Yuan Shen

    2015-01-01

    Graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) are novel nanofillers possessing attractive characteristics, including robust compatibility with most polymers, high absolute strength, and cost effectiveness. In this study, an outstanding synergetic effect on the grapheme nanoplatelets (GNPs) and multiwalled carbon nanotubes (CNTs) hybrids were used to reinforce epoxy composite and epoxy/carbon fiber composite laminates to enhance their mechanical properties. The mechanical propertie...

  2. Investigation of the mechanical properties and failure modes of hybrid natural fiber composites for potential bone fracture fixation plates.

    Science.gov (United States)

    Manteghi, Saeed; Mahboob, Zia; Fawaz, Zouheir; Bougherara, Habiba

    2017-01-01

    The purpose of this study is to investigate the mechanical feasibility of a hybrid Glass/Flax/Epoxy composite material for bone fracture fixation such as fracture plates. These hybrid composite plates have a sandwich structure in which the outer layers are made of Glass/Epoxy and the core from Flax/Epoxy. This configuration resulted in a unique structure compared to prior composites proposed for similar clinical applications. In order to evaluate the mechanical properties of this hybrid composite, uniaxial tension, compression, three-point bending and Rockwell Hardness tests were conducted. In addition, water absorption tests were performed to investigate the rate of water absorption for the specimens. This study confirms that the proposed hybrid composite plates are significantly more flexible axially compared to conventional metallic plates. Furthermore, they have considerably higher ultimate strength in tension, compression and flexion. Such high strength will ensure good stability of bone-implant construct at the fracture site, immobilize adjacent bone fragments and carry clinical-type forces experienced during daily normal activities. Moreover, this sandwich structure with stronger and stiffer face sheets and more flexible core can result in a higher stiffness and strength in bending compared to tension and compression. These qualities make the proposed hybrid composite an ideal candidate for the design of an optimized fracture fixation system with much closer mechanical properties to human cortical bone.

  3. High-Fidelity Modeling for Health Monitoring in Honeycomb Sandwich Structures

    Science.gov (United States)

    Luchinsky, Dimitry G.; Hafiychuk, Vasyl; Smelyanskiy, Vadim; Tyson, Richard W.; Walker, James L.; Miller, Jimmy L.

    2011-01-01

    High-Fidelity Model of the sandwich composite structure with real geometry is reported. The model includes two composite facesheets, honeycomb core, piezoelectric actuator/sensors, adhesive layers, and the impactor. The novel feature of the model is that it includes modeling of the impact and wave propagation in the structure before and after the impact. Results of modeling of the wave propagation, impact, and damage detection in sandwich honeycomb plates using piezoelectric actuator/sensor scheme are reported. The results of the simulations are compared with the experimental results. It is shown that the model is suitable for analysis of the physics of failure due to the impact and for testing structural health monitoring schemes based on guided wave propagation.

  4. Bioinspired bioartifical polymer hybrid composites for propolis vaginal delivery II: formulation and characterization

    Directory of Open Access Journals (Sweden)

    M. Glavas-Dodov

    2014-12-01

    Full Text Available In our previous work Box-Behnken experimental design was applied for formulation optimization of the thermoreversible mucoadhesive in situ vaginal hydrogels with propolis and optimized batches were identified. Optimized batches of bioartificial polymer hybrid composites (chitosan, Lutrol® F-127 and Lutrol® F-68 mixture (CP1, CP2, CP3 were prepared using so-called cold method. Formulation P3 (chitosan free was prepared in order to evaluate the effect of chitosan on the physico-chemical and biopharmaceutical properties of the polymer hybrid composites (gels. The pH values of the gels were 4-4.5. The gelation temperature for all formulations was in a range of 29-33 o C. Total flavonoids content was above 95%. Increase in concentration of Lutrol® F-127 and Lutrol® F-68/Lutrol® F-127 ratio lead to a higher viscosity values and slower gel erosion/dissolution. The presence of chitosan increased gel viscosity and hence slow-down erossion/dissoluiton. Propolis release rate was the highest in P3 which released propolis within 5 h, corresponding to time of complete erosion. The same correlation between erosion process and drug release rate was observed in CP1-CP3, where prolonged propolis release for more than 10 h was achieved. Microbiological quality was in accordance with the requirements of Ph. Eur. 7. All formulations demonstrated adequate stability at 5 ± 3 °C during 6 months. Based on overall results it can be anticipated that bioartificial blended bioinspired polymer hybrid composites for propolis vaginal delivery could represent intelligent delivery systems with physicochemical and biopharmaceutical properties in favor or efficacious and safe therapy of vaginal infections.

  5. Thermal Expansion and Thermal Conductivity Behaviors of Al-Si/SiC/graphite Hybrid Metal Matrix Composites (MMCs

    Directory of Open Access Journals (Sweden)

    S. Cem OKUMUS

    2012-12-01

    Full Text Available Aluminum-silicon based hybrid composites reinforced with silicon carbide and graphite particles were prepared by liquid phase particle mixing (melt stirring and squeeze casting. The thermal expansion and thermal conductivity behaviors of hybrid composites with various graphite contents (5.0; 7.5; 10 wt.% and different silicon carbide particle sizes (45 µm and 53 µm were investigated. Results indicated that increasing the graphite content improved the dimensional stability, and there was no obvious variation between the thermal expansion behaviors of the 45 µm and the 53 µm silicon carbide reinforced composites. The thermal conductivity of hybrid composites was reduced due to the enrichment of the graphite component.DOI: http://dx.doi.org/10.5755/j01.ms.18.4.3093

  6. Hybrid Finite Element Analysis of Free Edge Effect in Symmetric Composite Laminates

    Science.gov (United States)

    1983-06-01

    ANALYSIS OF FREE EDGE EFFECT IN L AUTHOR(S 61102F S.W. Lee237B J.J. Rhiu S.C. Won,, I ~ 7. PENOAMnG ORGANIZATION NAME(S) AND ADORES4 S) L. PERFORMING...ANALYSIS OF FREE EDGE EFFECT IN SYMMETRIC COMPOSITE LAMINATES S. W. Lee I 3. Phi S. C. Wong Department of Aerospace Engineering University of Maryland...collocation method. In this report, we present an efficient hybrid finite element method for analysis of interlaminar stress or free edge effect in

  7. A Gallium Oxide-Graphene Oxide Hybrid Composite for Enhanced Photocatalytic Reaction

    Directory of Open Access Journals (Sweden)

    Seungdu Kim

    2016-07-01

    Full Text Available Hybrid composites (HCs made up of gallium oxide (GaO and graphene oxide (GO were investigated with the intent of enhancing a photocatalytic reaction under ultraviolet (UV radiation. The material properties of both GaO and GO were preserved, even after the formation of the HCs. The incorporation of the GO into the GaO significantly enhanced the photocatalytic reaction, as indicated by the amount of methylene blue (MB degradation. The improvements in the reaction were discussed in terms of increased surface area and the retarded recombination of generated charged carriers.

  8. On the Fracture Toughness and Crack Growth Resistance of Bio-Inspired Thermal Spray Hybrid Composites

    Science.gov (United States)

    Resnick, Michael Murray

    the values of a real nacre. Although, the fracture toughness was primary property of this study and the values were well matched, the fracture behavior found to be somewhat different between the hybrid composite and nacre. In particular, the hybrid composite was unable to exhibit any significant toughness under slow crack growth conditions, which is the most attractive feature of nacre. This thesis focuses on first investigating the toughness in the sprayed hybrid composites by using standard resistance curve (R-curve) measurements. The study then focused on developing thermal spray modified hybrid composites with improved toughness, as well as with higher application temperatures, beyond the limitation of epoxy.

  9. A hybrid state vector approach to aeroelastic analysis with application to composite lifting surfaces

    Science.gov (United States)

    Lehman, L. L.

    1981-01-01

    A computational technique has been developed for performing preliminary design aeroelastic analyses of large aspect ratio lifting surfaces. This technique, applicable to both fixed and rotating wing configurations, is based upon a formulation of the structural equilibrium equations in terms of a hybrid state vector containing generalized force and displacement variables. An integrating matrix is employed to solve these equations for divergence and flutter eigenvalues and steady aeroelastic deformation. Results are presented for simple examples which verify the technique and demonstrate how it can be applied to analyze lifting surfaces, including those constructed from composite materials.

  10. Carbon Nanotube Enhanced Aerospace Composite Materials A New Generation of Multifunctional Hybrid Structural Composites

    CERN Document Server

    Kostopoulos, V

    2013-01-01

    The well documented increase in the use of high performance composites as structural materials in aerospace components is continuously raising the demands in terms of dynamic performance, structural integrity, reliable life monitoring systems and adaptive actuating abilities. Current technologies address the above issues separately; material property tailoring and custom design practices aim to the enhancement of dynamic and damage tolerance characteristics, whereas life monitoring and actuation is performed with embedded sensors that may be detrimental to the structural integrity of the component. This publication explores the unique properties of carbon nanotubes (CNT) as an additive in the matrix of Fibre Reinforced Plastics (FRP), for producing structural composites with improved mechanical performance as well as sensing/actuating capabilities. The successful combination of the CNT properties and existing sensing actuating technologies leads to the realization of a multifunctional FRP structure. The curre...

  11. Advanced radiator concepts utilizing honeycomb panel heat pipes (stainless steel)

    Science.gov (United States)

    Fleischman, G. L.; Tanzer, H. J.

    1985-08-01

    The feasibility of fabricating and processing moderate temperature range heat pipes in a low mass honeycomb sandwich panel configuration for highly efficient radiator fins for the NASA space station was investigated. A variety of honeycomb panel facesheet and core-ribbon wick concepts were evaluated within constraints dictated by existing manufacturing technology and equipment. Concepts evaluated include: type of material, material and panel thicknesses, wick type and manufacturability, liquid and vapor communication among honeycomb cells, and liquid flow return from condenser to evaporator facesheet areas. In addition, the overall performance of the honeycomb panel heat pipe was evaluated analytically.

  12. Self-powered pH sensor based on a flexible organic-inorganic hybrid composite nanogenerator.

    Science.gov (United States)

    Saravanakumar, Balasubramaniam; Soyoon, Shin; Kim, Sang-Jae

    2014-08-27

    In this study, we developed an innovative, flexible, organic-inorganic hybrid composite nanogenerator, which was used to drive a self-powered microwire-based pH sensor. The hybrid composite nanogenerator was fabricated using ZnO nanowire and piezoelectric polymer poly(vinylidene fluoride), through a simple, inexpensive solution-casting technique. The fabricated hybrid composite nanogenerator delivered a maximum open-circuit voltage of 6.9 V and a short-circuit current of 0.96 μA, with an output power of 6.624 μW under uniaxial compression. This high-performance, electric poling free composite nanogenerator opens up the possibility of industrial-scale fabrication. The hybrid nanogenerator demonstrated its ability to drive five green LEDs simultaneously, without using an energy-storage device. Additionally, we constructed a self-powered pH sensor, using a ZnO microwire powered with our hybrid nanogenerator. The output voltage varied according to changes in the pH level. This study demonstrates the feasibility of using a hybrid nanogenerator as a self-powered device that can be extended for use as a biosensor for environmental monitoring and/or as a smart, wearable, vibration sensor in future applications.

  13. Thermoplastic impact property improvement in hybrid natural fibre epoxy composite bumper beam

    Energy Technology Data Exchange (ETDEWEB)

    Davoodi, M M; Sapuan, S M; Ali, Aidy [Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia 43400 UPM Serdang, Selangor (Malaysia); Ahmad, D; Khalina, A, E-mail: makinejadm2@asme.org [Department of Biological and Agricultural Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia)

    2010-05-15

    Utilization of thermoset resin as a bumper beam composite matrix is currently more dominated in car manufacturer suppliers, because of availability, easy processing, low material cost and production equipment investment. Moreover, low viscosity, shrinkage and excellent flow facilitate better fibre impregnation and proper surface resin wetting. Three-dimensional cross linking curing increase impact, creep and environmental stress cracking resistance properties. Low impact properties of natural fibre epoxy composite, are main issues in its employment for automotive structural components. Impact properties in epoxy composite bumper beam could be increased by modifying the resin, reinforcement and manufacturing process as well as geometry parameters such as cross section, thickness, added ribs and fixing method optimizations could strengthen impact resistance. There are two main methods, flexibilisation and toughening, as modifying the resin in order to improve the impact properties of epoxy composite, which form single phase or two-phase morphology to make modifier as epoxy or from separate phase to keep the thermo-mechanical properties. Liquid rubber, thermoplastic, core shell particle and rigid particle are different methods of toughening improvements. In this research, thermoplastic toughening has used to improve impact properties in hybrid natural fibre epoxy composite for automotive bumper beam and has achieved reasonable impact improvements.

  14. RTA-treated carbon fiber/copper core/shell hybrid for thermally conductive composites.

    Science.gov (United States)

    Yu, Seunggun; Park, Bo-In; Park, Cheolmin; Hong, Soon Man; Han, Tae Hee; Koo, Chong Min

    2014-05-28

    In this paper, we demonstrate a facile route to produce epoxy/carbon fiber composites providing continuous heat conduction pathway of Cu with a high degree of crystal perfection via electroplating, followed by rapid thermal annealing (RTA) treatment and compression molding. Copper shells on carbon fibers were coated through electroplating method and post-treated via RTA technique to reduce the degree of imperfection in the Cu crystal. The epoxy/Cu-plated carbon fiber composites with Cu shell of 12.0 vol % prepared via simple compression molding, revealed 18 times larger thermal conductivity (47.2 W m(-1) K(-1)) in parallel direction and 6 times larger thermal conductivity (3.9 W m(-1) K(-1)) in perpendicular direction than epoxy/carbon fiber composite. Our novel composites with RTA-treated carbon fiber/Cu core/shell hybrid showed heat conduction behavior of an excellent polymeric composite thermal conductor with continuous heat conduction pathway, comparable to theoretical values obtained from Hatta and Taya model.

  15. Thermoplastic impact property improvement in hybrid natural fibre epoxy composite bumper beam

    Science.gov (United States)

    Davoodi, M. M.; Sapuan, S. M.; Ali, Aidy; Ahmad, D.; Khalina, A.

    2010-05-01

    Utilization of thermoset resin as a bumper beam composite matrix is currently more dominated in car manufacturer suppliers, because of availability, easy processing, low material cost and production equipment investment. Moreover, low viscosity, shrinkage and excellent flow facilitate better fibre impregnation and proper surface resin wetting. Three-dimensional cross linking curing increase impact, creep and environmental stress cracking resistance properties. Low impact properties of natural fibre epoxy composite, are main issues in its employment for automotive structural components. Impact properties in epoxy composite bumper beam could be increased by modifying the resin, reinforcement and manufacturing process as well as geometry parameters such as cross section, thickness, added ribs and fixing method optimizations could strengthen impact resistance. There are two main methods, flexibilisation and toughening, as modifying the resin in order to improve the impact properties of epoxy composite, which form single phase or two-phase morphology to make modifier as epoxy or from separate phase to keep the thermo-mechanical properties. Liquid rubber, thermoplastic, core shell particle and rigid particle are different methods of toughening improvements. In this research, thermoplastic toughening has used to improve impact properties in hybrid natural fibre epoxy composite for automotive bumper beam and has achieved reasonable impact improvements.

  16. Preparation and characterization of phosphorylated Zr-doped hybrid silica/PSF composite membrane.

    Science.gov (United States)

    Zhang, Yuqing; Jin, Zhenhua; Shan, Xing; Sunarso, Jaka; Cui, Ping

    2011-02-15

    Polysulfone (PSF) membranes are broadly applied in many fields owing to good physicochemical stability, resistance to oxidation and chlorine. But when treated with wastewater containing oil, PSF membranes are easy to be contaminated for its hydrophobicity, which can result in the declining of flux and lifespan of the membrane and limit their application in large scale. To enhance the capability of PSF membrane in the above circumstances, phosphorylated Zr-doped hybrid silica particles (SZP particles) were firstly prepared. SZP particles have various point defects inside their structure and lots of hydroxide radicals on their surface. SZP particles were added to the porous matrix of PSF to prepare a novel composite membrane (SZP/PSF) through a phase inversion process. Finally, the optimum preparation conditions of SZP/PSF composite membranes were determined. The optimum conditions are: the mass ratio of PSF, PEG400 and SZP is 12:10:10; ultrasound 10 min inside each 30 min; the pre-evaporating time is 10s. Optimized SZP/PSF composite membrane was characterized by scanning electron microscope (SEM) and ultrafiltration experiment. The results indicate that SZP particles can be uniformly dispersed in SZP/PSF composite membranes with excellent hydrophilic property, antifouling capability and tensile strength. Therefore, it can be concluded that the optimized SZP/PSF composite membrane is desirable in the treatment of wastewater containing oil and wastewater.

  17. Synthesis and characterization of insulin/zirconium phosphate@TiO2 hybrid composites for enhanced oral insulin delivery applications.

    Science.gov (United States)

    Safari, Mostafa; Kamari, Younes; Ghiaci, Mehran; Sadeghi-Aliabadi, Hojjat; Mirian, Mina

    2017-05-01

    In this work, a series of composites of insulin (Ins)/zirconium phosphate (ZrP) were synthesized by intercalation method, then, these composites were coated with TiO2 by sol-gel method to prepare Ins/ZrP@TiO2 hybrid composites and the drug release of the composites was investigated by using UV-Vis spectroscopy. Ins/ZrP (10, 30, 60 wt%) composites were prepared by intercalation of insulin into the ZrP layers in water. Then Ins/ZrP composites were coated with different amounts of TiO2 (30, 50, 100 wt %) by using titanium tetra n-butoxide, as precursor. Formation of intercalated Ins/ZrP and Ins/ZrP@TiO2 hybrid composites was characterized by FT-IR, FE-SEM, BET and XRD analysis. Zeta potential of the optimized Ins/ZrP@TiO2 hybrid composite was determined -27.2 mV. Cytotoxic effects of the optimized Ins/ZrP@TiO2 hybrid composite against HeLa and Hek293T cell lines were evaluated using MTT assay and the results showed that designed drug delivery system was not toxic in biological environment. Compared to the Ins/ZrP composites, incorporation of TiO2 coating enhanced the drug entrapment considerably, and reduced the drug release. The Ins/ZrP composites without TiO2 coating released the whole drug after 30 min in pH 7.4 (phosphate buffer solution) while the TiO2-coated composites released the entrapped drug after 20 h. In addition to increasing the shelf life of hormone, this nanoencapsulation and nanocoating method can convert the insulin utilization from injection to oral and present a painless and more comfortable treatment for diabetics.

  18. Optimization of process parameters in drilling of fibre hybrid composite using Taguchi and grey relational analysis

    Science.gov (United States)

    Vijaya Ramnath, B.; Sharavanan, S.; Jeykrishnan, J.

    2017-03-01

    Nowadays quality plays a vital role in all the products. Hence, the development in manufacturing process focuses on the fabrication of composite with high dimensional accuracy and also incurring low manufacturing cost. In this work, an investigation on machining parameters has been performed on jute-flax hybrid composite. Here, the two important responses characteristics like surface roughness and material removal rate are optimized by employing 3 machining input parameters. The input variables considered are drill bit diameter, spindle speed and feed rate. Machining is done on CNC vertical drilling machine at different levels of drilling parameters. Taguchi’s L16 orthogonal array is used for optimizing individual tool parameters. Analysis Of Variance is used to find the significance of individual parameters. The simultaneous optimization of the process parameters is done by grey relational analysis. The results of this investigation shows that, spindle speed and drill bit diameter have most effect on material removal rate and surface roughness followed by feed rate.

  19. Examining of abrasion resistance of hybrid composites reinforced with SiC and Cgr particles

    Directory of Open Access Journals (Sweden)

    M. Łągiewka

    2008-08-01

    Full Text Available The presented work discusses the influence of the type and volume percentage of particulate reinforcement consisting of mixed silicon carbide and graphite on the abrasion wear of hybrid composites with AlMg10 matrix. Also the macro photos of frictional surfaces have been shown and the results of hardness measurements have been presented. The performed examinations have allowed for stating that the mixture of SiC and Cgr particles changes in favour the tribological properties of the matrix alloy. It has been also proved that introducing hard reinforcing particles along with soft lubricating ones allows for achieving the material exhibiting high abrasion resistance, and moreover, the graphite particles protect the abraded surface from the destructive action of silicon carbide particles. Also hardness measurements have been performed and the resulting conclusion is that the composite hardness increases with an increase in volume fraction of the reinforcing particles.

  20. On the Design, Characterization and Simulation of Hybrid Metal-Composite Interfaces

    Science.gov (United States)

    Kießling, R.; Ihlemann, J.; Pohl, M.; Stommel, M.; Dammann, C.; Mahnken, R.; Bobbert, M.; Meschut, G.; Hirsch, F.; Kästner, M.

    2017-02-01

    Multi-material lightweight designs are a key feature for the development of innovative and resource-efficient products. In the development of a hybrid composite, the interface between the joined components has to be considered in detail as it represents a typical location of the initialization of failure. This contribution gives an overview of the simulative engineering of metal-composite interfaces. To this end, several design aspects on the microscale and macroscale are explained and methods to model the mechanical behavior of the interface within finite element simulations. This comprises the utilization of cohesive elements with a continuum description of the interface. Likewise, traction-separation based cohesive elements, i.e. a zero-thickness idealization of the interface, are outlined and applied to a demonstration example. Within these finite element simulations, the constitutive behavior of the connected components has to be described by suitable material models. Therefore, inelastic material models at large strains are formulated based on rheological models.

  1. Measurement and Prediction of the Thermomechanical Response of Shape Memory Alloy Hybrid Composite Beams

    Science.gov (United States)

    Davis, Brian; Turner, Travis L.; Seelecke, Stefan

    2008-01-01

    An experimental and numerical investigation into the static and dynamic responses of shape memory alloy hybrid composite (SMAHC) beams is performed to provide quantitative validation of a recently commercialized numerical analysis/design tool for SMAHC structures. The SMAHC beam specimens consist of a composite matrix with embedded pre-strained SMA actuators, which act against the mechanical boundaries of the structure when thermally activated to adaptively stiffen the structure. Numerical results are produced from the numerical model as implemented into the commercial finite element code ABAQUS. A rigorous experimental investigation is undertaken to acquire high fidelity measurements including infrared thermography and projection moire interferometry for full-field temperature and displacement measurements, respectively. High fidelity numerical results are also obtained from the numerical model and include measured parameters, such as geometric imperfection and thermal load. Excellent agreement is achieved between the predicted and measured results of the static and dynamic thermomechanical response, thereby providing quantitative validation of the numerical tool.

  2. Investigation of the Thermomechanical Response of Shape Memory Alloy Hybrid Composite Beams

    Science.gov (United States)

    Davis, Brian A.

    2005-01-01

    Previous work at NASA Langley Research Center (LaRC) involved fabrication and testing of composite beams with embedded, pre-strained shape memory alloy (SMA) ribbons. That study also provided comparison of experimental results with numerical predictions from a research code making use of a new thermoelastic model for shape memory alloy hybrid composite (SMAHC) structures. The previous work showed qualitative validation of the numerical model. However, deficiencies in the experimental-numerical correlation were noted and hypotheses for the discrepancies were given for further investigation. The goal of this work is to refine the experimental measurement and numerical modeling approaches in order to better understand the discrepancies, improve the correlation between prediction and measurement, and provide rigorous quantitative validation of the numerical model. Thermal buckling, post-buckling, and random responses to thermal and inertial (base acceleration) loads are studied. Excellent agreement is achieved between the predicted and measured results, thereby quantitatively validating the numerical tool.

  3. Numerical estimation of structure composition in laser-arc hybrid welded joints

    Directory of Open Access Journals (Sweden)

    W. Piekarska

    2010-10-01

    Full Text Available This work presents results of numerical estimation of the structure composition in laser-arc hybrid welded joints. Temperature field wasobtained by the solution of the heat transfer equation with activity of inner heat sources. Convective motion of liquid metal in the welding pool, latent heat of fusion and latent heat of phase transformation were taken into account in the algorithms for numerical analysis of the temperature field. The volumetric fractions of arising phases were determined on the basis of Johnson - Mehl - Avrami (JMA model for diffusive transformations and Koistinen - Marburger (KM model for martensitic transformation. On the basis of calculated temperature distribution the structure composition in welded joint was numerically estimated, taking into account CHT and CCT diagrams for S355 steel.

  4. Measurement and Prediction of the Thermomechanical Response of Shape Memory Alloy Hybrid Composite Beams

    Science.gov (United States)

    Davis, Brian; Turner, Travis L.; Seelecke, Stefan

    2008-01-01

    An experimental and numerical investigation into the static and dynamic responses of shape memory alloy hybrid composite (SMAHC) beams is performed to provide quantitative validation of a recently commercialized numerical analysis/design tool for SMAHC structures. The SMAHC beam specimens consist of a composite matrix with embedded pre-strained SMA actuators, which act against the mechanical boundaries of the structure when thermally activated to adaptively stiffen the structure. Numerical results are produced from the numerical model as implemented into the commercial finite element code ABAQUS. A rigorous experimental investigation is undertaken to acquire high fidelity measurements including infrared thermography and projection moire interferometry for full-field temperature and displacement measurements, respectively. High fidelity numerical results are also obtained from the numerical model and include measured parameters, such as geometric imperfection and thermal load. Excellent agreement is achieved between the predicted and measured results of the static and dynamic thermomechanical response, thereby providing quantitative validation of the numerical tool.

  5. On the Design, Characterization and Simulation of Hybrid Metal-Composite Interfaces

    Science.gov (United States)

    Kießling, R.; Ihlemann, J.; Pohl, M.; Stommel, M.; Dammann, C.; Mahnken, R.; Bobbert, M.; Meschut, G.; Hirsch, F.; Kästner, M.

    2016-09-01

    Multi-material lightweight designs are a key feature for the development of innovative and resource-efficient products. In the development of a hybrid composite, the interface between the joined components has to be considered in detail as it represents a typical location of the initialization of failure. This contribution gives an overview of the simulative engineering of metal-composite interfaces. To this end, several design aspects on the microscale and macroscale are explained and methods to model the mechanical behavior of the interface within finite element simulations. This comprises the utilization of cohesive elements with a continuum description of the interface. Likewise, traction-separation based cohesive elements, i.e. a zero-thickness idealization of the interface, are outlined and applied to a demonstration example. Within these finite element simulations, the constitutive behavior of the connected components has to be described by suitable material models. Therefore, inelastic material models at large strains are formulated based on rheological models.

  6. Development of SnS2/RGO nanosheet composite for cost-effective aqueous hybrid supercapacitors

    Science.gov (United States)

    Chauhan, Himani; Singh, Manoj K.; Kumar, Praveen; Hashmi, Safir Ahmad; Deka, Sasanka

    2017-01-01

    The development of low cost supercapacitor cells with unique capacitive properties is essential for many domestic and industrial purposes. Here we report the first ever application of SnS2-reduced graphene oxide (SnS2/RGO) layered nanocomposite as a superior electrode material for symmetric aqueous hybrid supercapacitors. We synthesized SnS2/RGO nanocomposite comprised of nanosheets of SnS2 and graphene oxide via a one-pot hydrothermal approach. in situ as-synthesized SnS2/RGO is devised for the first time to give high specific capacitance 500 Fg-1, energy density 16.67 Wh kg-1 and power density 488 W kg-1. The cell retains 95% charge/discharge cycle stability up to 1000 cycles. In-short, the SnS2/RGO nanosheet composite presented is a novel and advanced material for application in high stability moderate value hybrid supercapacitors. All the currently available surveys in literature state the potential applicability of SnS2 as the anode material for reversible lithium/sodium ion batteries (LIBs/NIBs) but there is a lack of equivalent studies on electrochemical capacitors. We filled up this knowledge gap by the use of the same material in a cost-effective, highly active hybrid supercapacitor application by utilizing its pseudocapacitance property combined with the layered capacitance property of graphene sheets.

  7. Evaluation of microleakage in hybrid composite restoration with different intermediate layers and curing cycles

    Directory of Open Access Journals (Sweden)

    Mohan R Sakri

    2016-01-01

    Full Text Available Objective: To evaluate the impact of bulk or incremental curing of hybrid composite resin with different intermediate layers on interfacial microleakage. Materials and Methods: The recently extracted, sixty noncarious human mandibular molars were selected for the study. The standardized mesio-occluso-distal cavity with the occlusal cavity of 2 mm depth, 3 mm buccolingual width and proximal box dimension of 4 mm buccolingual width and 2 mm depth was prepared on all experimental teeth. The samples were divided into six groups of ten each. Group I was without an intermediate layer. Group II and III had 1 mm flowable composite liner, with incremental and bulk curing cycle, respectively. The Group IV, V, and VI had a self-cure composite liner with incremental and bulk curing. The teeth subjected to thermocycling and kept in 0.5% basic fuchsine dye for 24 h. The teeth were sectioned and observed under a stereomicroscope to grade them according to the extent of microleakage. The obtained data were statistically analyzed with Kruskal–Wallis and post hoc comparison test to understand the difference between the groups. Results: The Group II with flowable composite along incremental curing showed the least microleakage at both enamel (0.30 and cementum surface (0.50. The groups with self-cure composite liner were less effective than flowable composite. The microleakage at the enamel interface was less compared cementum interface across the groups. The groups with bulk curing were more prone to microleakage than incremental curing cycle. Conclusions: Within the limitation of the study, it was concluded that intermediate flowable composite with incremental curing was better suited to reduce microleakage.

  8. SERS of semiconducting nanoparticles (TiO{sub 2} hybrid composites).

    Energy Technology Data Exchange (ETDEWEB)

    Musumeci, A.; Gosztola, D.; Schiller, T.; Dimitrijevic, N.; Mujica, V.; Martin, D.; Rajh, T. (Center for Nanoscale Materials)

    2009-04-13

    Raman scattering of molecules adsorbed on the surface of TiO{sub 2} nanoparticles was investigated. We find strong enhancement of Raman scattering in hybrid composites that exhibit charge transfer absorption with TiO{sub 2} nanoparticles. An enhancement factor up to {approx}10{sup 3} was observed in the solutions containing TiO{sub 2} nanoparticles and biomolecules, including the important class of neurotransmitters such as dopamine and dopac (3,4-dihydroxy-phenylacetic acid). Only selected vibrations are enhanced, indicating molecular specificity due to distinct binding and orientation of the biomolecules coupled to the TiO{sub 2} surface. All enhanced modes are associated with the asymmetric vibrations of attached molecules that lower the symmetry of the charge transfer complex. The intensity and the energy of selected vibrations are dependent on the size and shape of nanoparticle support. Moreover, we show that localization of the charge in quantized nanoparticles (2 nm), demonstrated as the blue shift of particle absorption, diminishes SERS enhancement. Importantly, the smallest concentration of adsorbed molecules shows the largest Raman enhancements suggesting the possibility for high sensitivity of this system in the detection of biomolecules that form a charge transfer complex with metal oxide nanoparticles. The wavelength-dependent properties of a hybrid composite suggest a Raman resonant state. Adsorbed molecules that do not show a charge transfer complex show weak enhancements probably due to the dielectric cavity effect.

  9. Fe3O4/carbon coated silicon ternary hybrid composite as supercapacitor electrodes

    Science.gov (United States)

    Oh, Ilgeun; Kim, Myeongjin; Kim, Jooheon

    2015-02-01

    In this study, Fe3O4/carbon-coated Si ternary hybrid composites were fabricated. A carbon layer was directly formed on the surface of Si by the thermal vapor deposition. The carbon-coating layer not only prevented the contact between Si and reactive electrolyte but also provided anchoring sites for the deposition of Fe3O4. Fe3O4 nanoparticles were deposited on the surface of carbon-coated Si by the hydrazine reducing method. The morphology and structure of Fe3O4 and carbon layer were characterized via X-ray diffractometry, field emission scanning electron microscopy, field emission transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analyses. These characterizations indicate that a carbon layer was fully coated on the Si particles, and Fe3O4 particles were homogeneously deposited on the carbon-coated Si particles. The Fe3O4/carbon-coated Si electrode exhibited enhanced electrochemical performance, attributed to the high conductivity and stability of carbon layer and pseudocapacitive reaction of Fe3O4. The proposed ternary-hybrid composites may be potentially useful for the fabrication of high-performance electrodes.

  10. Optimization of CNC Turning Parameters on Aluminum 7015 Hybrid Metal Matrix Composite Using Taguchi Robust Design

    Directory of Open Access Journals (Sweden)

    SENTHIL KUMAR. M.P

    2014-08-01

    Full Text Available The Aluminum Hybrid Metal Matrix Composites (Al-HMMC are finding numerous applications in many areas like Automobile, Piston and Cylinder and Aerospace, etc. Adding a third element into the metal matrix composite makes it hybrid. The Reinforcement of SiC and Graphite used in this Al-HMMC improves its strength. The present investigation is to find the optimum machining parameter of CNC turning centre on Al-HMMC. The main objective is to find the optimum cutting parameters to achieve low value of surface roughness and high Material Removal Rate (MRR. The cutting parameters considered in this experimental investigation are cutting speed, feed rate and depth of cut. Taguchi L27 orthogonal array was chosen to conduct the experiments. Signal to Noise ratio (S/N and Analysis of Variance (ANOVA were used to analyze the effect of cutting parameters on surface roughness and MRR. The contribution by each cutting parameter to surface roughness and MRR was also determined.

  11. Investigations to Model and Analyse the OHC Strength of Hybrid Composites

    Directory of Open Access Journals (Sweden)

    B. Siddeswarappa

    2009-01-01

    Full Text Available In recent years, the utilization of hybrid polymer matrix composite materials in many engineering fields has increasedtremendously. The present investigation is devoted on fabric-reinforced hybrid composite laminates with different volumefractions of the constituent materials; epoxy resin, plain-woven glass fabric, and textile satin fabric. Fracture toughness ofa material has immense importance in the determination of the resistance of the material to crack propagation. Hence thisarticle explores the findings of the experimentation on the compressive strength and fracture toughness of fabric-reinforcedlaminates with 0/90O & ± 45O orientation with five notch configurations. The fracture toughness has been found to increasecontinuously with increased volumes of glass fabric and it is less dependent on notch size upto certain limit. Data collectedduring experimentations are validated using analysis of variance (ANOVA technique. Percentage contribution of each parameterwas evaluated using ANOVA technique with fiber content, orientation and notch size as input parameters, while theoutput parameter being the OHC strength of the laminate

  12. Complex roles of hybrid lipids in the composition, order, and size of lipid membrane domains.

    Science.gov (United States)

    Hassan-Zadeh, Ebrahim; Baykal-Caglar, Eda; Alwarawrah, Mohammad; Huang, Juyang

    2014-02-11

    Hybrid lipids (HL) are phospholipids with one saturated chain and one unsaturated chain. HL are hypothesized to act as linactants (i.e., 2D surfactants) in cell membranes, reducing line tension and creating nanoscopic lipid domains. Here we compare three hybrid lipids of different chain unsaturation (16:0-18:1PC (POPC), 16:0-18:2PC (PLPC), and 16:0-20:4PC (PAPC)) in their abilities to alter the composition, line tension, order, and compactness of lipid domains. We found that the liquid-ordered (Lo) and liquid-disordered (Ld) lipid domains in PAPC/di18:0PC(DSPC)/cholesterol and PLPC/DSPC/cholesterol mixtures are micrometer-sized, and only the POPC/DSPC/cholesterol system has nanoscopic domains. The results indicate that some HLs with polyunsaturated chains are not linactants, and the monounsaturated POPC displays both properties of weak linactants and "Ld-phase" lipids such as di18:1PC (DOPC). The obtained phase boundaries from giant unilamellar vesicles (GUV) show that both POPC and PLPC partition well in the Lo phases. Our MD simulations reveal that these hybrid lipids decrease the order and compactness of Lo domains. Thus, hybrid lipids distinguish themselves from other lipid groups in this combined "partitioning and loosening" ability, which could explain why the Lo domains of GUVs, which often do not contain HL, are more compact than the raft domains in cell membranes. Our line tension measurement and Monte Carlo simulation both show that even the monounsaturated POPC is a weak linactant with only modest ability to occupy domain boundaries and reduce line tension. A more important property of HLs is that they can reduce physical property differences of Lo and Ld bulk domains, which also reduces line tension at domain boundaries.

  13. EFFECT OF CLIMATIC FACTOR ON THE MECHANICAL BEHAVIOUR OF AEOLIAN BLADES: APPLICATION OF HYBRID COMPOSITE MATERIALS

    Directory of Open Access Journals (Sweden)

    F. Mili

    2015-08-01

    Full Text Available The great interest which the wind power brings in the development of the various economic sectors encourages to contribute in the improvement of the hydrothermal and mechanical performances of the blades of wind rotors with horizontal axis. The use of composite materials involves a profit of substantial weight, strength to the directional constraints that the blade will undergo during its work and a reduction of the aerodynamic and mechanical losses. The adoption of composite materials with unidirectional reinforcement carbon/epoxy makes it possible to get for the structure a high wear resistance and a reduction of the phenomenon of bearing pressure created around the airfoil of the blade moving relative compared to the speed of the wind. The evaluation of the behavior of such composites with [+θ/- θ]4S stacking sequence, with the combined effect of the temperature, the moisture and the tensile effort constitutes the principal axis of this contribution. In order to minimize the costs, our analysis will direct towards hybrid composite materials glass-carbon/epoxy being presented in the form of symmetrical laminates [+q/0°]2S and antisymmetric [+q/0°/90°/-q]. The results obtained showed that their use contributes to the improvement of their thermomechanical behavior by involving profits of performance, weight, cost savings and energy.

  14. α MnMoO₄/graphene hybrid composite: high energy density supercapacitor electrode material.

    Science.gov (United States)

    Ghosh, Debasis; Giri, Soumen; Moniruzzaman, Md; Basu, Tanya; Mandal, Manas; Das, Chapal Kumar

    2014-07-28

    A unique and cost effective hydrothermal procedure has been carried out for the synthesis of hexahedron shaped α MnMoO4 and its hybrid composite with graphene using three different weight percentages of graphene. Characterization techniques, such as XRD, Raman and FTIR analysis, established the phase and formation of the composite. The electrochemical characterization of the pseudocapacitive MnMoO4 and the MnMoO4/graphene composites in 1 M Na2SO4 displayed highest specific capacitances of 234 F g(-1) and 364 F g(-1), respectively at a current density of 2 A g(-1). Unlike many other pseudocapacitive electrode materials our prepared materials responded in a wide range of working potentials of (-)1 V to (+)1 V, which indeed resulted in a high energy density without substantial loss of power density. The highest energy densities of 130 Wh kg(-1) and 202.2 Wh kg(-1) were achieved, respectively for the MnMoO4 and the MnMoO4/graphene composite at a constant power delivery rate of 2000 W kg(-1). The synergistic effect of the graphene with the pseudocapacitive MnMoO4 caused an increased cycle stability of 88% specific capacitance retention after 1000 consecutive charge discharge cycles at 8 A g(-1) constant current density, which was higher than the virgin MnMoO4 with 84% specific capacitance retention.

  15. Effects of hybrid composition of LCP and glass fibres on abrasive wear of reinforced LLDPE

    Indian Academy of Sciences (India)

    S A R Hashmi; Ajay Naik; Navin Chand

    2006-02-01

    The hybrid of liquid crystalline polymer (LCP) fibres and glass fibres (GF) provide a combination of modulus and toughness to semi-crystalline linear-low-density-polyethylene (LLDPE). LCP and GF fibres reinforced composites were studied using two-body abrasion tester under different applied loads. Two sets of fibre reinforced LLDPE, 10 and 20 vol%, were investigated. The contents of LCP and glass fibres were varied as 25, 50, 75 and 100 vol% of overall volume of fibres in LLDPE. The effect of replacing glass fibre with LCP fibre on wear is reported. Wear loss increased with the applied loads and glass fibre contents in LLDPE. The replacements of glass fibres with LCP fibres improved abrasive wear resistance of composite. The composite containing 20 vol% of glass fibres in LLDPE showed the specific wear rate nearly double to that of LCP fibre reinforced LLDPE. Incorporation of LCP fibre improved wear resistance of glass fibre reinforced LLDPE. Worn surfaces were studied using SEM. Glass fibres were broken in small debris and removed easily whereas LCP fibres yielded to fibrillation during abrasive action. The overall wear rate was governed by the composition and test conditions.

  16. A Numerical Study on Electrical Percolation of Polymer-Matrix Composites with Hybrid Fillers of Carbon Nanotubes and Carbon Black

    Directory of Open Access Journals (Sweden)

    Yuli Chen

    2014-01-01

    Full Text Available The electrical percolation of polymer-matrix composites (PMCs containing hybrid fillers of carbon nanotubes (CNTs and carbon black (CB is estimated by studying the connection possibility of the fillers using Monte Carlo simulation. The 3D simulation model of CB-CNT hybrid filler is established, in which CNTs are modeled by slender capped cylinders and CB groups are modeled by hypothetical spheres with interspaces because CB particles are always agglomerated. The observation on the effects of CB and CNT volume fractions and dimensions on the electrical percolation threshold of hybrid filled composites is then carried out. It is found that the composite electrical percolation threshold can be reduced by increasing CNT aspect ratio, as well as increasing the diameter ratio of CB groups to CNTs. And adding CB into CNT composites can decrease the CNT volume needed to convert the composite conductivity, especially when the CNT volume fraction is close to the threshold of PMCs with only CNT filler. Different from previous linear assumption, the nonlinear relation between CB and CNT volume fractions at composite percolation threshold is revealed, which is consistent with the synergistic effect observed in experiments. Based on the nonlinear relation, the estimating equation for the electrical percolation threshold of the PMCs containing CB-CNT hybrid fillers is established.

  17. Sliding Wear Properties of Hybrid Aluminium Composite Reinforced by Particles of Palm Shell Activated Carbon and Slag

    Directory of Open Access Journals (Sweden)

    Zamri Yusoff

    2011-09-01

    Full Text Available In present work, dry sliding wear tests were conducted on hybrid composite reinforced with natural carbon based particles such as palm shell activated carbon (PSAC and slag. Hybrid composites containing 5 -20 wt.% of both reinforcements with average particles sizes about 125μm were prepared by conventional powder metallurgy technique, which involves the steps of mixing, compacting and sintering. Dry sliding experiments were conducted in air at room temperature using a pin-on-disc self-built attach to polisher machine. The disc which acted as the mating surface material was made of mild steel (120 HV cut from commercial mild steel sheet (2 mm thickness into 100mm diameter. The influence of the applied load was investigated under a constant sliding velocity of 0.1m/s with the applied loads at 3N, 11N and 51N. The contribution of the reinforcement content and the applied load as well as the sliding distance on the wear process and the wear rate have been investigated. The contribution of synergic factors such as applied load, sliding distance and reinforcement content (wt.% have been studied using analysis of variance (ANOVA. All synergic factors contribute to the wear process of all tested composites. Among synergic factors, the applied load is the highest contribution to wear process on both composites (Al/PSAC and Al/Slag and hybrid composite. The degree of improvement of wear resistance of hybrid composite is strongly dependent on the reinforcement content.

  18. Relationship between the degree of conversion, solubility and salivary sorption of a hybrid and a nanofilled resin composite.

    Science.gov (United States)

    da Silva, Eduardo Moreira; Almeida, Giselle Soares; Poskus, Laiza Tatiana; Guimarães, José Guilherme Antunes

    2008-01-01

    This study analyzed the relationship between the degree of conversion (DC), solubility, and salivary sorption of a hybrid (Filtek P 60) and a nanofilled resin composite (Filtek Supreme), and evaluated the influence of the light-activation mode on these properties. Two light-activation modes were used: Conventional (C; 850 mW/cm(2) for 20 s) and Soft-start (SS; 100-1,000 mW/cm(2) for 10 s + 1,000 mW/cm(2) for 10 s). The DC (%) was evaluated by FT-Raman spectroscopy. The solubility and salivary sorption were measured after immersion in artificial saliva for 7 days. Data were analyzed by ANOVA and Student-Newman-Keuls' test and linear regression analysis (a = 0.05). The DC varied from 50.52% (nanofilled composite) to 57.15% (hybrid composite), and was influenced by the light-activation mode: C > SS. The solubility (0.45 microg/mm(3)) and salivary sorption (8.04 microg/mm(3)) of the nanofilled composite were greater than those of the hybrid composite (0.40 microg/mm(3) / 6.87 microg/mm(3)), and were influenced by the light-activation mode: SS > C. Correlation was found between DC and solubility (r = - 0.89, pcomposites may present higher degradation in the oral environment than hybrid ones. Soft-start light-activation mode may increase the solubility of resin composites.

  19. Investigation of Mechanical and Electrical Properties of Hybrid Composites Reinforced with Carbon Nanotubes and Micrometer-Sized Silica Particles

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Yun; You, Byeong Il; Ahn, Ji Ho; Lee, Gyo Woo [Chonbuk Nat’l Univ., Junju (Korea, Republic of)

    2016-12-15

    In this study, to enhance the electrical insulation of composite specimens in addition to the improved mechanical properties, the epoxy composite were reinforced with carbon nanotubes and silica particles. Tensile strength, Young's modulus, dynamic mechanical behavior, and electrical resistivity of the specimens were measured with varied contents of the two fillers. The mechanical and electrical properties were discussed, and the experimental results related to the mechanical properties of the specimens were compared with those from several micromechanics models. The hybrid composites specimens with 0.6 wt% of carbon nanotubes and 50 wt% of silica particles showed improved mechanical properties, with increase in tensile strength and Young's modulus up to 11% and 35%, respectively, with respect to those of the baseline specimen. The electrical conductivity of the composite specimens with carbon nanotubes filler also improved. Further, the electrical insulation of the hybrid composites specimens with the two fillers improved in addition to the improvement in mechanical properties.

  20. Characterization of exposures to nanoscale particles and fibers during solid core drilling of hybrid carbon nanotube advanced composites.

    Science.gov (United States)

    Bello, Dhimiter; Wardle, Brian L; Zhang, Jie; Yamamoto, Namiko; Santeufemio, Christopher; Hallock, Marilyn; Virji, M Abbas

    2010-01-01

    This work investigated exposures to nanoparticles and nanofibers during solid core drilling of two types of advanced carbon nanotube (CNT)-hybrid composites: (1) reinforced plastic hybrid laminates (alumina fibers and CNT); and (2) graphite-epoxy composites (carbon fibers and CNT). Multiple real-time instruments were used to characterize the size distribution (5.6 nm to 20 microm), number and mass concentration, particle-bound polyaromatic hydrocarbons (b-PAHs), and surface area of airborne particles at the source and breathing zone. Time-integrated samples included grids for electron microscopy characterization of particle morphology and size resolved (2 nm to 20 microm) samples for the quantification of metals. Several new important findings herein include generation of airborne clusters of CNTs not seen during saw-cutting of similar composites, fewer nanofibers and respirable fibers released, similarly high exposures to nanoparticles with less dependence on the composite thickness, and ultrafine (composite material.

  1. Comparative analysis of the mechanical and thermal properties of polyester hybrid composites reinforced by jute and glass fiber.

    Directory of Open Access Journals (Sweden)

    Braga, R. A

    2015-05-01

    Full Text Available This work describes the study to investigate and compare the mechanical and thermal properties of raw jute and glass fiber reinforced polyester hybrid composites. To improve the mechanical properties, jute fiber was hybridized with glass fiber. Polyester resin, jute and glass fibers were laminated in three weight ratios(77/23/0, 68/25/7 and 56/21/23 respectively to form composites. The tensile, flexural, impact, density, thermal and water absorption tests were carried out using hybrid composite samples. This study shows that the addition of jute fiber and glass fiber in polyester, increase the density, the impact energy, the tensile strength and the flexural strength, but decrease the loss mass in function of temperature and the water absorption. Morphological analysis was carried out to observe fracture behavior and fiber pull-out of the samples using scanning electron microscope.

  2. Analysis of the mechanical and thermal properties of jute and glass fiber as reinforcement epoxy hybrid composites.

    Science.gov (United States)

    Braga, R A; Magalhaes, P A A

    2015-11-01

    This work describes the study to investigate and compare the mechanical and thermal properties of raw jute and glass fiber reinforced epoxy hybrid composites. To improve the mechanical properties, jute fiber was hybridized with glass fiber. Epoxy resin, jute and glass fibers were laminated in three weight ratios (69/31/0, 68/25/7 and 64/18/19) respectively to form composites. The tensile, flexural, impact, density, thermal and water absorption tests were carried out using hybrid composite samples. This study shows that the addition of jute fiber and glass fiber in epoxy, increases the density, the impact energy, the tensile strength and the flexural strength, but decreases the loss mass in function of temperature and the water absorption. Morphological analysis was carried out to observe fracture behavior and fiber pull-out of the samples using scanning electron microscope. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Repair bond strength of resin composite to a novel CAD/CAM hybrid ceramic using different repair systems.

    Science.gov (United States)

    Elsaka, Shaymaa E

    2015-01-01

    This study evaluated the repair bond strength of a nanohybrid resin composite to a novel CAD/CAM hybrid ceramic based on four intraoral ceramic repair systems. Vita Enamic (VE) CAD/CAM hybrid ceramic was used in this study. Specimens were divided into five test groups according to the repair method performed on the ceramic surface: Gr C (No treatment; control); Gr CZ (Cimara Zircon); Gr PR (Porcelain Repair); Gr CR (Clearfil Repair); and Gr CS (CoJet system). Nanohybrid resin composite (GrandioSO) was packed onto treated ceramic surfaces for adhesion testing using microtensile bond strength test. Debonded specimens were examined with a stereomicroscope and SEM to determine the fracture mode. Data were analyzed using ANOVA and Tukey's HSD test. PR and CZ repair systems significantly enhanced the bond strength of nanohybrid resin composite to VE CAD/CAM hybrid ceramic when compared with the other tested repair systems.

  4. Mechanical properties and production quality of hand-layup and vacuum infusion processed hybrid composite materials for GFRP marine structures

    Directory of Open Access Journals (Sweden)

    Sang-Young Kim

    2014-09-01

    Full Text Available Glass Fiber Reinforced Plastic (GFRP structures are primarily manufactured using hand lay-up or vacuum infusion techniques, which are cost-effective for the construction of marine vessels. This paper aims to investigate the mechanical properties and failure mechanisms of the hybrid GFRP composites, formed by applying the hand lay-up processed exterior and the vacuum infusion processed interior layups, providing benefits for structural performance and ease of manufacturing. The hybrid GFRP composites contain one, two, and three vacuum infusion processed layer sets with consistent sets of hand lay-up processed layers. Mechanical properties assessed in this study include tensile, compressive and in-plane shear properties. Hybrid composites with three sets of vacuum infusion layers showed the highest tensile mechanical properties while those with two sets had the highest mechanical properties in compression. The batch homogeneity, for the GFRP fabrication processes, is evaluated using the experimentally obtained mechanical properties.

  5. Influence of weave structures on the tribological properties of hybrid Kevlar/PTFE fabric composites

    Science.gov (United States)

    Gu, Dapeng; Yang, Yulin; Qi, Xiaowen; Deng, Wei; Shi, Lei

    2012-09-01

    The existing research of the woven fabric self-lubricating liner mainly focus on the tribological performance improvements and the service life raised by changing different fiber type combinations, adding additive modification, and performing fiber surface modification. As fabric composites, the weave structures play an important role in the mechanical and tribological performances of the liners. However, hardly any literature is available on the friction and wear behavior of such composites with different weave structures. In this paper, three weave structures (plain, twill 1/3 and satin 8/5) of hybrid Kevlar/PTFE fabric composites are selected and pin-on-flat linear reciprocating wear studies are done on a CETR tester under different pressures and different frequencies. The relationship between the tensile strength and the wear performance are studied. The morphologies of the worn surfaces under the typical test conditions are analyzed by means of scanning electron microscopy (SEM). The analysis results show that at 10 MPa, satin 8/5 performs the best in friction-reduction and antiwear performance, and plain is the worst. At 30 MPa, however, the antiwear performance is reversed and satin 8/5 does not even complete the 2 h wear test at 16 Hz. There is no clear evidence proving that the tensile strength has an influence on the wear performance. So the different tribological performance of the three weave structures of fabric composites may be attributed to the different PTFE proportions in the fabric surface and the different wear mechanisms. The fabric composites are divided into three regions: the lubrication region, the reinforced region and the bonding region. The major mechanisms are fatigue wear and the shear effects of the friction force in the lubrication region. In the reinforced region fiber-matrix de-bonding and fiber breakage are involved. The proposed research proposes a regional wear model and further indicates the wear process and the wear mechanism

  6. Computational modeling and relevance of numerical convergence for the investigation of thermal expansion behavior for aluminium hybrid composites

    Science.gov (United States)

    Krishna, S. A. Mohan; Shridhar, T. N.; Krishnamurthy, L.

    2016-06-01

    The thermal characterization and analysis of composite materials has been increasingly important in a wide range of applications. The coefficient of thermal expansion (CTE) is one of the most important properties of metal matrix composites (MMCs). Since nearly all MMCs are used in various temperature ranges, measurement of CTE as a function of temperature is necessary in order to know the behavior of the material. In this research paper, the evaluation of CTE or thermal expansivity has been accomplished for Al 6061, silicon carbide and graphite hybrid MMCs from room temperature to 300∘C. Aluminium-based composites reinforced with silicon carbide and graphite particles have been prepared by stir casting technique. The thermal expansivity behavior of hybrid composites with different percentage compositions of reinforcements has been investigated. The results have indicated that the thermal expansivity of different compositions of hybrid MMCs decrease by the addition of graphite with silicon carbide and Al 6061. Empirical models have been validated for the evaluation of thermal expansivity of composites. Numerical convergence test has been accomplished to investigate the thermal expansion behavior of composites.

  7. The effect of mouthrinses on salivary sorption, solubility and surface degradation of a nanofilled and a hybrid resin composite.

    Science.gov (United States)

    Almeida, Giselle Soares; Poskus, Laiza Tatiana; Guimarães, José Guilherme Antunes; da Silva, Eduardo Moreira

    2010-01-01

    This in vitro study evaluated the effect of mouth rinses on salivary sorption (Sp), solubility (Sl) and surface degradation of a nanofilled (Z350) and hybrid (P60) resin composite. Specimens (6 mm in diameter and 1 mm thick) of a nanofilled and hybrid resin composite were immersed in artificial saliva at 37 degrees C for seven days. Twice a day, the samples (n = 5) were immersed in 20 ml of three mouth rinses: Listerine, Plax Mint and Plax. A control group was maintained in artificial saliva. Sp and Sl were evaluated based on ISO 4049:2000(E) and surface degradation by scanning electron microscopy-SEM. The degree of conversion (DC%) of resin composites was obtained by using an FT-IR spectrometer equipped with an attenuated total reflectance crystal (ATR). The data were analyzed using the Student's t-test, ANOVA and Tukey test for multiple comparisons. No significant difference in DC% was found between the two resin composites (p composite exposed to Listerine (p hybrid composite in the control group (artificial saliva) and Plax presented the lowest sorption (p composites exposed to Listerine (p composite.

  8. Investigation of Tribological Behavior of a Novel Hybrid Composite Prepared with Al-Coconut Shell Ash Mixed with Graphite

    Science.gov (United States)

    Siva Sankara Raju, R.; Panigrahi, M. K.; Ganguly, R. I.; Srinivasa Rao, G.

    2017-08-01

    The present investigation develops a next-generation hybrid Al metal matrix composite using coconut shell ash (CSA) and graphite (Gr) reinforcement. Stir-casting is adapted to prepare an Al-1100-based composite. Three other composites of Al-Al2O3, Al-Al2O3-Gr, and Al-CSA are prepared that contain equivalent volume fractions of Al2O3, CSA, and Gr. These assist in comparisons among the three composites and the developed hybrid Al-CSA-Gr composite. The study reveals that the addition of 3 pct Gr improves the specific strength, toughness, and tribological properties. The Al-CSA composite shows better mechanical properties, such as tensile strength and hardness, than the other three composites. Gr addition helps the hybrid Al-CSA-Gr composite to attain better tribological properties with a slightly lower specific strength. Scanning electron microscopy studies of the worn material surfaces corroborate the findings of the abrasion testing. Elemental analyses by energy-dispersive X-ray spectroscopy of the debris from the counter-face of the tribo surface confirm the presence of Al, O, Si, Fe, Mn, and C.

  9. Enhanced mechanical properties and biocompatibility of novel hydroxyapatite/TOPAS hybrid composite for bone tissue engineering applications.

    Science.gov (United States)

    Ain, Qurat Ul; Khan, Ahmad Nawaz; Nabavinia, Mahboubeh; Mujahid, Mohammad

    2017-06-01

    The bioactivity and mechanical properties of hybrid composites of hydroxyapatite (HA) in cyclic olefinic copolymer (COC) also known commercially as TOPAS are investigated, first time, for regeneration and repair of the bone tissues. HA is synthesized to obtain the spherically shaped nanoparticles in the size range of 60±20nm. Various concentrations of HA ranging from 1 to 30wt% are dispersed in TOPAS using sodium dodecyl sulfate (SDS) coupling agent for better dispersion and interaction of hydrophilic HA with hydrophobic TOPAS. Scanning electron microscope shows the uniform dispersion of HA≤10wt% in TOPAS and at higher concentrations >10wt%, agglomeration occurs in the hybrid composites. Tunable mechanical properties are achieved as the compressive modulus and strength are increased around 140% from 6.4 to 15.3MPa and 185% from 0.26 to 0.74MPa, respectively. Such increase in the mechanical properties of TOPAS is attributed to the anchoring of the polymer chains in the vicinity of HA nanoparticles owing to better dispersion and interfacial interactions. In comparison to neat TOPAS, hybrid composites of TOPAS/HA promoted the cell adhesion and proliferation significantly. The cell density and proliferation of TOPAS/HA hybrid composites is enhanced 9 and 3 folds, respectively, after 1day culturing in preosteoblasts cells. Moreover, the morphology of cells changed from spherical to flattened spread morphology demonstrating clearly the migration of the cells for the formation of interconnected cellular network. Additionally, very few dead cells are found in hybrid composites showing their cytocompatibility. Overall, the hybrid composites of TOPAS/HA exhibited superior strength and stiffness along with enhanced cytocompatibility for bone tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Hybrid carbon fiber/carbon nanotube composites for structural damping applications.

    Science.gov (United States)

    Tehrani, M; Safdari, M; Boroujeni, A Y; Razavi, Z; Case, S W; Dahmen, K; Garmestani, H; Al-Haik, M S

    2013-04-19

    Carbon nanotubes (CNTs) were grown on the surface of carbon fibers utilizing a relatively low temperature synthesis technique; graphitic structures by design (GSD). To probe the effects of the synthesis protocols on the mechanical properties, other samples with surface grown CNTs were prepared using catalytic chemical vapor deposition (CCVD). The woven graphite fabrics were thermally shielded with a thin film of SiO2 and CNTs were grown on top of this film. Raman spectroscopy and electron microscopy revealed the grown species to be multi-walled carbon nanotubes (MWCNTs). The damping performance of the hybrid CNT-carbon fiber-reinforced epoxy composite was examined using dynamic mechanical analysis (DMA). Mechanical testing confirmed that the degradations in the strength and stiffness as a result of the GSD process are far less than those encountered through using the CCVD technique and yet are negligible compared to the reference samples. The DMA results indicated that, despite the minimal degradation in the storage modulus, the loss tangent (damping) for the hybrid composites utilizing GSD-grown MWCNTs improved by 56% compared to the reference samples (based on raw carbon fibers with no surface treatment or surface grown carbon nanotubes) over the frequency range 1-60 Hz. These results indicated that the energy dissipation in the GSD-grown MWCNTs composite can be primarily attributed to the frictional sliding at the nanotube/epoxy interface and to a lesser extent to the stiff thermal shielding SiO2 film on the fiber/matrix interface.

  11. Study of Two-Dimensional Materials with Honeycomb Geometry

    NARCIS (Netherlands)

    Boneschanscher, M.P.

    2014-01-01

    Honeycomb structures have already fascinated mankind since ancient times. They were observed in various natural occurring phenomena, from the structure of the beehive of the honeybee that granted the structure its name, to the inner structure of butterfly wings, bones, and insect eyes. The honeycomb

  12. Clean Electrical-Discharge Machining Of Delicate Honeycomb

    Science.gov (United States)

    Johnson, Clarence S.

    1993-01-01

    Precise recesses in fragile metal honeycomb blocks formed in special electrical-discharge machining process. Special tooling used, and recesses bored with workpiece in nonstandard alignment. Cutting electrode advances into workpiece along x axis to form pocket of rectangular cross section. Deionized water flows from fitting, along honeycomb tubes of workpiece, to electrode/workpiece interface.

  13. Wear behaviour of Al/(Al{sub 2}O{sub 3} + ZrB{sub 2} + TiB{sub 2}) hybrid composites fabricated by hot pressing

    Energy Technology Data Exchange (ETDEWEB)

    Farhadinia, Faranak; Sedghi, Arman [Imam Khomeini International University, Qazvin (Iran, Islamic Republic of). Materials Engineering Dept.

    2015-02-15

    The dry sliding wear behaviour of Al/(Al{sub 2}O{sub 3} + ZrB{sub 2} + TiB{sub 2}) hybrid composite was tested by using a pin-on-disc testing machine at room temperature and 300 C. Hybrid reinforcement was fabricated by mechanically activated combustion synthesis, and the composites were prepared by hot pressing of aluminium powder and hybrid reinforcement. The effect of sliding distance, hybrid reinforcement content and temperature on the wear properties of the composites has been investigated. For comparison, the same tests were conducted on Al/Al{sub 2}O{sub 3} composite and pure aluminium. Hybrid composites have higher wear resistance than pure aluminium and Al/Al{sub 2}O{sub 3} composites at room temperature and 300 C. A study of wear surfaces showed that plastic deformation induced wear and adhesive wear are the dominant mechanisms at room and high temperature, respectively.

  14. Effects of leached components from a hybrid resin composite on the reproductive system of male mice

    Directory of Open Access Journals (Sweden)

    Taher Akbari Saeed

    2012-01-01

    Full Text Available Background and Aims: There is concern that leached components from dental composites may cause adverse changes in the reproductive health. This study aimed to assess the effects of leached components from a hybrid resin composite on the reproductive system of male mice.Materials and Methods: In the present animal study, twenty adult Syrian male mice were divided into two groups of 10 mice each. In the test group, components which leached from samples made from Filtek Z250 resin composite into 75% ethanol were daily administered to the mice for 28 days. In the control group, the procedure was repeated in the same way as the test group but without placing composite samples in the solution. Then, the body weight, weights of paired testes, Gonado Somatic Index, sperm viability, sperm motility, epididymal sperm reserve and daily sperm production were recorded. Four male mice in each group were mated with untreated female mice for 10 days. After that, the number of pregnant females and number of infants were recorded. The data were analyzed using repeated measures ANOVA, Chi-square test and t-test.Results: There was a significant reduction in the sperm viability and sperm motility of male mice in the test group compared to the control group (P=0.001. There was no any significant differences in other parameters between two groups (P>0.05.Conclusion: This study showed that the leached components from resin composites cannot cause infertility but they could potentially cause some adverse effects on the reproductive system of male mice.

  15. EFFECT OF SURFACE SEALING ON STAIN RESISTANCE OF A NANO-HYBRID RESIN COMPOSITE*

    Directory of Open Access Journals (Sweden)

    Günçe SAYGI

    2015-04-01

    Full Text Available Purpose: This study investigated the influence of sealant application on stain resistance of a nanohybrid resin composite compared to the efficacy of a bonding agent used as a surface sealant on prolonging color stability of the resin composite. Materials and Methods: 28 disc-shaped materials were prepared from a nano-hybrid resin composite Filtek Z550 and assigned to four groups: G1K: nonsealed; G2:Adper Single Bond; G3: Fortify ; G4: Biscover LV. After 24 h storage in distilled water at 37˚C, all specimens were subjected to thermocycling and immersed into coffee solution. Color measurements were performed using spectrophotometer (VITA Easyshade; Vident according to CIEL*a*b* system. Results: Color change values were significantly different among the groups in each evaluation period except for after thermocycling (p<0.05. For 7 days evaluation period, the difference between G3 and G4 group was statistically significant while G4 exhibited statistically significant differences (p<0.05 and p<0.0001 respectively compared to control (G1 in 14 day whereas no significant difference was found between GI and GII in 28-day evaluation period. However, ΔE values of sealed specimens (GIII, GIV differed significantly from non-sealed (GI specimens after 28 days of immersion in coffee solution (p<0.05 and p<0.0001 respectively. Conclusion: It may be concluded that using a bonding agent as a surface sealant does not increase stain resistance of resin composites of the sealants evaluated. Biscover LV showed the highest efficacy to prolong color stability of the resin composite.

  16. Some Exploitation Properties of Wood Plastic Hybrid Composites Based on Polypropylene and Plywood Production Waste

    Science.gov (United States)

    Kajaks, Janis; Kalnins, Karlis; Uzulis, Sandris; Matvejs, Juris

    2015-12-01

    polypropylenewood hybrid composites (WPHC) physical-mechanical and other exploitation properties.

  17. Ultralightweight silver nanowires hybrid polyimide composite foams for high-performance electromagnetic interference shielding.

    Science.gov (United States)

    Ma, Jingjing; Zhan, Maosheng; Wang, Kai

    2015-01-14

    Ultralightweight silver nanowires (AgNWs) hybrid polyimide (PI) composite foams with microcellular structure and low density of 0.014-0.022 g/cm(3) have been fabricated by a facile and effective one-pot liquid foaming process. The tension flow generated during the cell growth induced the uniform dispersion of AgNWs throughout the cell walls. The interconnected AgNWs network in the cell walls combined with the large 3D AgNWs network caused by 3D structure of foams provided fast electron transport channels inside foams. The electromagnetic interference (EMI) shielding effectiveness (SE) of these foams increased with increasing AgNWs loading as well as the nanowire aspect ratio due to the increasing connections of the conduction AgNWs network. Appropriate surface treatment like etching or spraying facilitated the construction of the seamlessly interconnected 2D AgNWs network on the surface, which could effectively reflect electromagnetic waves. Maximum specific EMI SE of values of 1210 dB·g(-1)·cm(3) at 200 MHz, 957 dB·g(-1)·cm(3) at 600 MHz, and 772 dB·g(-1)·cm(3) at 800-1500 MHz were achieved in sprayed composite foams containing composite materials. The reflections of interconnected AgNWs networks on the surface and inside foams combined with the multiple reflections at interfaces contributed to the shielding effect.

  18. Interlocked graphene-Prussian blue hybrid composites enable multifunctional electrochemical applications.

    Science.gov (United States)

    Zhang, Minwei; Hou, Chengyi; Halder, Arnab; Ulstrup, Jens; Chi, Qijin

    2017-03-15

    There has been increasing interest recently in mixed-valence inorganic nanostructure functionalized graphene composites, represented by Prussian blue, because they can cost-effectively apply to biosensors and energy devices. In this work, we present a one-pot green method to synthesize interlocked graphene-Prussian Blue hybrid composites as high-performance materials for biosensors and supercapacitor electrodes. Given the fact that graphene oxide (GO) can act as an electron acceptor, we used iron(II) and glucose as co-reducing agents to reduce GO under mild reaction conditions without introducing toxic agents. High quality Prussian blue nanocubes with no or little coordinated water were generated simultaneously. Reduced graphene oxide (rGO) was thus functionalized by Prussian blue nanocubes via chemical bonding to form a kind of interlocked microstructure with high stability and good conductivity. The as-synthesized composites were tested for biosensing of hydrogen peroxide (H2O2) and as supercapacitor electrode materials. The specific capacitance of the microcomposite based electrodes can reach 428Fg(-1), with good cycling stability. The microcomposite also displays high performance catalysis towards electroreduction of H2O2 with a high sensitivity of 1.5Acm(-2)M(-1).

  19. Dependence of SERS enhancement on the chemical composition and structure of Ag/Au hybrid nanoparticles.

    Science.gov (United States)

    Chaffin, Elise; O'Connor, Ryan T; Barr, James; Huang, Xiaohua; Wang, Yongmei

    2016-08-01

    Noble metal nanoparticles (NPs) such as silver (Ag) and gold (Au) have unique plasmonic properties that give rise to surface enhanced Raman scattering (SERS). Generally, Ag NPs have much stronger plasmonic properties and, hence, provide stronger SERS signals than Au NPs. However, Ag NPs lack the chemical stability and biocompatibility of comparable Au NPs and typically exhibit the most intense plasmonic resonance at wavelengths much shorter than the optimal spectral region for many biomedical applications. To overcome these issues, various experimental efforts have been devoted to the synthesis of Ag/Au hybrid NPs for the purpose of SERS detections. However, a complete understanding on how the SERS enhancement depends on the chemical composition and structure of these nanoparticles has not been achieved. In this study, Mie theory and the discrete dipole approximation have been used to calculate the plasmonic spectra and near-field electromagnetic enhancements of Ag/Au hybrid NPs. In particular, we discuss how the electromagnetic enhancement depends on the mole fraction of Au in Ag/Au alloy NPs and how one may use extinction spectra to distinguish between Ag/Au alloyed NPs and Ag-Au core-shell NPs. We also show that for incident laser wavelengths between ∼410 nm and 520 nm, Ag/Au alloyed NPs provide better electromagnetic enhancement than pure Ag, pure Au, or Ag-Au core-shell structured NPs. Finally, we show that silica-core Ag/Au alloy shelled NPs provide even better performance than pure Ag/Au alloy or pure solid Ag and pure solid Au NPs. The theoretical results presented will be beneficial to the experimental efforts in optimizing the design of Ag/Au hybrid NPs for SERS-based detection methods.

  20. Degree of conversion of micro-hybrid, nano-hybrid and Ormocer composites using LED and QTH light-curing units

    Directory of Open Access Journals (Sweden)

    Seied Mostafa Fatemi

    2012-01-01

    Full Text Available Background and Aims: The aim of this study was to measure the degree of conversion (DC of three types of composite resins (micro-hybrid, nano-hybrid and Ormocer with different light curing units (LED LCU and QTH LCU in two depths.Materials and Methods: Three commercially available dental resin composites were used in this study: (Tetric Ceram, Ivoclar Vivadent, Liechtenstein-A2 shade, (Tetric Evoceram, Ivoclar Vivadent, Liechtenstein-A2 shade, (Ceram X, Dentsply, Germany-M2 shade. Specimens were divided into two groups, 5 specimens were photo-activated by QTH unit (Coltolux 75-Colten and the other five specimens were cured by LED (Demi-Kerr. Then each specimen was sectioned at the top surface and at 2-mm depth. The DC was measured by FT-IR(Bruker-tensor 27. The data were analyzed by 3-way ANOVA test.Results: There was significant difference between tested composite resins (P<0.001. The results of top surfaces were significantly different from those observed at 2-mm depth (P<0.001. The type of curing unit affected the polymerization of Ceram X resin composite.Conclusion: This study showed a significant difference in the degree of conversion in different thicknesses within three groups of resin composites.

  1. Effect of organic-inorganic hybrid P123-em-SBA15 on lithium transport properties of composite polymer electrolyte

    Institute of Scientific and Technical Information of China (English)

    XI Jingyu; HUANG Xiaobin; TANG Xiaozhen

    2004-01-01

    A novel PEO-based composite polymer electrolyte by using organic-inorganic hybrid EO20PO70EO20-em- mesoporous silica (P123-em-SBA15) as the filler has been developed. The experiment results show that P123-em- SBA15 can enhance the lithium-ion transference number of the composite polymer electrolyte, which is induced by the special topology structure of P123 in P123-em-SBA15 hybrid. In addition, room temperature ionic conductivity of the composite polymer electrolyte can also be increased by about two orders of magnitude. The excellent lithium transport properties suggest that PEO-LiClO4-P123-em-SBA15 composite polymer electrolyte can be used as electrolyte materials for all solid-state rechargeable lithium polymer batteries.

  2. Hybrid Nano composite Membranes for PEMFC Applications; Conception et elaboration de membranes hybrides nanocomposites pour l'application pile a combustible PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Niepceron, F.

    2008-03-15

    This work aims at validating a new concept of hybrid materials for the realization of proton exchange membranes, an essential constituent of PEM fuel cells. The originality of this nano-composite hybrid concept corresponds to a separation of the membrane's properties. We investigated the preparation of composite materials based on an inert, relatively low cost, polymer matrix (PVDF-HFP) providing the mechanical stability embedding inorganic fillers providing the necessary properties o f proton-conduction and water retention. The first step of this work consisted in the modification of fumed silica to obtain a proton-conducting filler. An ionic exchange capacity (CEI) equal to 3 meq/g was obtained by the original grafting of sodium poly(styrene-sulfonate) chains from the surface of particles. Nano-composite hybrid membranes PVDF-HFP/functionalized silica were accomplished by a film casting process. The coupling of the morphological and physicochemical analyses validated the percolation of the inorganic phase for 30 wt.% of particles. Beyond 40 % of loading, measured protonic conductivity is higher than the reference membrane Nafion 112. Finally, these membranes presented high performances, above 0.8 W/cm{sup 2}, in single-cell fuel cell tests. A compromise is necessary according to the rate of loading between performances in fuel cell and mechanical properties of the membrane. 50 % appeared as best choice with, until 90 C, a remarkable thermal stability of the performances. (author)

  3. The effect of fibre layering pattern in resisting bending loads of natural fibre-based hybrid composite materials

    Directory of Open Access Journals (Sweden)

    Jusoh Muhamad Shahirul Mat

    2016-01-01

    Full Text Available The effect of fibre layering pattern and hybridization on the flexural properties of composite hybrid laminates between natural fibres of basalt, jute and flax with synthetic fibre of E-glass reinforced epoxy have been investigated experimentally. Results showed that the effect fibre layering pattern was highly significant on the flexural strength and modulus, which were strongly dependent on the hybrid configuration between sandwich-like (SL and intercalation (IC sequence of fibre layers. In addition, specific modulus based on the variation densities of the hybrid laminates was used to discover the best combination either basalt, jute or flax with E-glass exhibits superior properties concerning on the strength to weight-ratio. Generally, SL sequence of glass/basalt exhibited superior strength and stiffness compared with glass/jute and glass/flax in resisting bending loads. In terms of hybridization effect, glass/jute was found to be the best combination with E-glass compared to the rest of natural fibres investigated in the present study. Hence, the proper stacking sequences and material selection are among predominant factors that influence on mechanical properties and very crucial in designing composite hybrid system to meet the desired requirements.

  4. Bioactive Hybrid Composite Membrane with Enhanced Antimicrobial Properties for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Abin Davis

    2016-06-01

    Full Text Available   Azadirachta indica extract has been explored as an antibiotic in hygienic chitosan matrix system to enhance antimicrobial and medicinal property in a cost effective manner. The hygienic composite system has been successfully fabricated via solvent casting. The antibacterial activities of the hybrid system were examined by agar diffusion method against gram positive S.aureus and gram negative K. pneumoniae. From conventional antibacterial test for 24 h, the system exhibited an excellent antimicrobial activity against both bacterial strains in ranges of 1.2 cm - 1.5 cm for S. aureus and 1.8 cm - 2.3 cm for K. pneumoniae Fourier transform infrared spectroscopy revealed successfully embedded A. indica on the chitosan substrate via weak electrostatic interaction, resulting in the easy release of the additive. Moreover, atomic force microscopy showed a membrane roughness of 0.084 nm which confirms the uniform distribution of the additive throughout the membrane. These hybrid membranes have potential applications in skin tissue engineering, wound healing and as coatings for implantable scaffold material.

  5. Bioactivity and degradability of hybrids nano-composites materials with great application as bone tissue substitutes

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Téllez, D.A.; Téllez-Jurado, L.; Chávez-Alcalá, J.F., E-mail: fchaveza@hotmail.com

    2014-12-05

    Highlights: • pH has an effect on the degradation process of the hybrid materials. • Weight loss depends on the change of pH during the degradation process. • Bioactivity in the materials is strongly related to calcium and pH. - Abstract: In this work, hybrids with great application as bioactive materials having different compositions based on siloxane network were prepared. In vitro bioactivity and in vitro degradability tests were carried out in the materials by soaking them into simulated body fluid (SBF) and into phosphate buffer solution (PBS) to prove their apatite-forming ability and to show their degradation process, respectively. In both in vitro tests, measurements of pH and loss weight were made to observe bioactivity and degradation processes. To prove growth of HA, the materials were characterized through X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. The results showed that some samples have better bioactivity than others. It was found that the incorporation of CaO component into the network of the materials results in an increase of the apatite-forming ability in SBF. Moreover, during the degradation tests, all the samples presented weight loss, especially the ones that contain CaO.

  6. Mechanical properties of composites made of hybrid fabric impregnated with silica nanoparticles and epoxy resin

    Science.gov (United States)

    Kordani, N.; Alizadeh, M.; Lohrasby, F.; Khajavi, R.; Baharvandi, H. R.; Rezanejad, M.; Ahmadzadeh, M.

    2017-09-01

    In this study, the mechanical properties of composites will be examined which were made from Kenaf and hybrid fabric with a simple structure that was coated with epoxy resin and nano silica particles. This fabric cotton has a different situation in terms of yarn score and the type of fiber that is used in textiles. Nano silica particles of 200 nm, polyethylene glycol with 200 molecular weights and ethanol with mechanical weight molecular with ratio of 6:1 will be mixed. Suspension of 60% was chosen according to the silica particles. The D6264 standard test for concentrated force was carried out through the cone edge to determine the strength of each of the samples. Increasing of resistance against penetration in the Kenaf samples from the raw until impregnated with the shear thickening fluid is less than the hybrid samples. Slippage of the fibers with the change of round edge indenter to cone edge indenter has changed. Penetration by cone edge to the cloth is done with lower force and it shows the effect of slippage of fibers on the resistance of the penetration. Samples impregnated with the shear thickening fluid in comparison with epoxy resin have lower resistance. Slippage of natural fibers in comparison with synthetic fibers is lower and on the other hand the average of friction between fibers in the natural fibers is more than synthetic fibers.

  7. Optimization of woven jute/glass fibre-reinforced polyester hybrid composite solar parabolic trough collector

    Science.gov (United States)

    Reddy, K. S.; Singla, Hitesh

    2017-07-01

    In the present work, structural analysis of 5.77m × 4m woven jute (J)/glass (G) fibre-reinforced polyester hybrid composite solar parabolic trough is carried out based on trough parameters to obtain the minimum RMS local slope deviation, termed as SDx value under gravity loading. The optimization is done by varying parameters viz. direction and size of reinforced conduits, stacking number and sequence of hybrid trough laminate at fibre orientation of Δθ=45° and Δθ=60° amongst the layers at 0° collector angle. The analysis revealed that the configuration in which the conduits are placed in both X and Y directions is preferred over other configurations to scale down the effect of wind loads. Furthermore it has been observed that laminate of the order [0°G/45°G/-45°J/90°J]s undergoes minimum surface deformation amongst all the other configurations at conduit reinforcement in both X and Y directions for a conduit thickness of 0.75 mm and radius of 10 mm and obtains the overall SDx value of 1.3492 mrad. The results shows that proposed trough model is very promising and evolves a cost effective system.

  8. Synthesis and Gas Transport Properties of Hyperbranched Polyimide–Silica Hybrid/Composite Membranes

    Directory of Open Access Journals (Sweden)

    Masako Miki

    2013-12-01

    Full Text Available Hyperbranched polyimide–silica hybrids (HBPI–silica HBDs and hyperbranched polyimide–silica composites (HBPI–silica CPTs were prepared, and their general and gas transport properties were investigated to clarify the effect of silica sources and preparation methods. HBPI–silica HBDs and HBPI–silica CPTs were synthesized by two-step polymerization of A2 + B3 monomer system via polyamic acid as precursor, followed by hybridizing or blending silica sources. Silica components were incorporated by the sol-gel reaction with tetramethoxysilane (TMOS or the addition of colloidal silica. In HBPI-silica HBDs, the aggregation of silica components is controlled because of the high affinity of HBPI and silica caused by the formation of covalent bonds between HBPI and silica. Consequently, HBPI-silica HBDs had good film formability, transparency, and mechanical properties compared with HBPI-silica CPTs. HBPI-silica HBD and CPT membranes prepared via the sol-gel reaction with TMOS showed specific gas permeabilities and permselectivities for CO2/CH4 separation, that is, both CO2 permeability and CO2/CH4 selectivity increased with increasing silica content. This result suggests that gas transport can occur through a molecular sieving effect of the porous silica network derived from the sol-gel reaction and/or through the narrow interfacial region between the silica networks and the organic matrix.

  9. Hybrid photovoltaic devices from regioregular polythiophene and ZnO nanoparticles composites

    Energy Technology Data Exchange (ETDEWEB)

    Das, Narayan Ch. [Indiana University Cyclotron Facility, 2401 Milo B Sampson Lane, Bloomington, IN 47408 (United States); Sokol, Paul E. [Indiana University Cyclotron Facility, 2401 Milo B Sampson Lane, Bloomington, IN 47408 (United States); Department of Physics, Indiana University, Bloomington, IN 47405 (United States)

    2010-12-15

    The nano size zinc oxide (ZnO) was successfully synthesized at low temperature solution method. The structural characterization, size and distribution of synthesized ZnO particles were performed using X-ray diffraction (XRD) and neutron scattering technique. The hybrid polymer-metal oxide bulk heterojunction solar cell has been fabricated by blending of ZnO and regioregular poly(3-hexylthiophene) (P3HT) through solution process and flow coating on the flexible substrate. The decrease in the photoluminescence (PL) emission intensity more than 79% for ZnO:P3HT composites film indicates high charge generation efficiency. The cell shows the V{sub oc} and I{sub sc} of 0.33 V and 6.5 mA/cm{sup 2}, respectively. The performance and stability of cell were investigated using UV illumination of white light. (author)

  10. Evaluation of mechanical properties of natural hybrid fibers, reinforced polyester composite materials

    Directory of Open Access Journals (Sweden)

    S. Kasiviswanathan

    2015-12-01

    Full Text Available The composite materials are replacing the traditional materials, because of its superior properties such as high tensile strength, low thermal expansion, high strength to weight ratio. The developments of new materials are on the anvil and are growing day by day. In this work the effect of glass fibre hybridization with the randomly oriented natural fibers has been evaluated. The sisal (S, banana (B, E-glass synthetic fibers were chopped and reinforced with polyester matrix. Six layers were prepared in the following stacking sequence of S/B/G, S/G/B, G/S/B, G/S/B/G/S/B/G, S/G/B//S/G/B, B/G/S/B/G/S. The mechanical properties like impact strength, flexural strength and tensile strength were investigated and compared. It was observed that the addition of two and three layer of glass fiber can improve the mechanical properties like tensile, Flexural and impact strength.

  11. Magnetic composites based on hybrid spheres of aluminum oxide and superparamagnetic nanoparticles of iron oxides

    Energy Technology Data Exchange (ETDEWEB)

    Braga, Tiago P. [Langmuir - Laboratorio de Adsorcao e Catalise, Departamento de Quimica Analitica e Fisico-Quimica, Universidade Federal do Ceara, CP 6021, CEP 60455-970 Campus do Pici, Fortaleza (Brazil); Vasconcelos, Igor F. [Departamento de Engenharia Metalurgica e de Materiais, Universidade Federal do Ceara, Fortaleza (Brazil); Sasaki, Jose M. [Laboratorio de Raios X, Departamento de Fisica, Universidade Federal do Ceara, Campus do Pici, Fortaleza, CE (Brazil); Fabris, J.D.; Oliveira, Diana Q.L. de [Departamento de Quimica, Universidade Federal de Minas Gerais, Belo Horizonte (Brazil); Valentini, Antoninho, E-mail: valent@ufc.b [Langmuir - Laboratorio de Adsorcao e Catalise, Departamento de Quimica Analitica e Fisico-Quimica, Universidade Federal do Ceara, CP 6021, CEP 60455-970 Campus do Pici, Fortaleza (Brazil)

    2010-03-15

    Materials containing hybrid spheres of aluminum oxide and superparamagnetic nanoparticles of iron oxides were obtained from a chemical precursor prepared by admixing chitosan and iron and aluminum hydroxides. The oxides were first characterized with scanning electron microscopy, X-ray diffraction, and Moessbauer spectroscopy. Scanning electron microscopy micrographs showed the size distribution of the resulting spheres to be highly homogeneous. The occurrence of nano-composites containing aluminum oxides and iron oxides was confirmed from powder X-ray diffraction patterns; except for the sample with no aluminum, the superparamagnetic relaxation due to iron oxide particles were observed from Moessbauer spectra obtained at 298 and 110 K; the onset six line-spectrum collected at 20 K indicates a magnetic ordering related to the blocking relaxation effect for significant portion of small spheres in the sample with a molar ratio Al:Fe of 2:1.

  12. Fabrication of alumina filled hybrid buckypaper composites and their enhancement of microwave absorbing performance

    Science.gov (United States)

    Miao, Hsin-Yuan; Liu, Jih-Hsin; Saravanan, L.

    2015-06-01

    Alumina (Al2O3)-filled multiwalled carbon nanotube buckypapers (BPs) with different Al2O3 loadings (5-50 wt%) were successfully synthesised. Structural and morphological analysis performed with x-ray diffraction and field-emission scanning electron microscopy, respectively, confirmed the presence of stable α-phase Al2O3 particles in the Al2O3-BP composites. The formation of flexible Al2O3-BP hybrid nanocomposites (5-15 wt%) was attributed to the strong interfacial polarisation and high conductivity; compared with pure Al2O3 and BP. The nanocomposites with optimised alumina loadings demonstrated enhanced microwave absorption (>90%) and a broader absorption bandwidth in the investigated high-frequency region.

  13. Special hybrid stress element for stress analyses around circular cutouts in laminated composites

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A 3-dimensional hybrid stress element with a traction-free cylindrical surface based on amodified complementary energy principle has been derived for efficient and accurate analysis of stressconcentration around circular cutouts in thin to thick laminated composites. New expressions of sixstress components are developed by using three stress-functions in cylindrical co-ordinates, so that thehomogeneous equilibrium equations, the interlayer surface transverse-stresses and the traction-freeboundary condition on the cylindrical surface are satisfied exactly, while the interelement traction conti-nuity has been relaxed via the Lagrange multiplier method. Transverse-shear deformation effects areincorporated in each layer with displacement continuity enforced along interlayer surface. Selected ex-amples are used to demonstrate the efficiency and accuracy of the present special element.

  14. Effect of Impact Damage and Open Hole on Compressive Strength of Hybrid Composite Laminates

    Science.gov (United States)

    Hiel, Clement; Brinson, H. F.

    1993-01-01

    Impact damage tolerance is a frequently listed design requirement for composites hardware. The effect of impact damage and open hole size on laminate compressive strength was studied on sandwich beam specimens which combine CFRP-GFRP hybrid skins and a syntactic foam core. Three test specimen configurations have been investigated for this study. The first two were sandwich beams which were loaded in pure bending (by four point flexure). One series had a skin damaged by impact, and the second series had a circular hole machined through one of the skins. The reduction of compressive strength with increasing damage (hole) size was compared. Additionally a third series of uniaxially loaded open hole compression coupons were tested to generate baseline data for comparison with both series of sandwich beams.

  15. Hybrid composite laminates reinforced with Kevlar/carbon/glass woven fabrics for ballistic impact testing.

    Science.gov (United States)

    Randjbaran, Elias; Zahari, Rizal; Jalil, Nawal Aswan Abdul; Majid, Dayang Laila Abang Abdul

    2014-01-01

    Current study reported a facile method to investigate the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption by running the ballistic test at the high velocity ballistic impact conditions. The velocity and absorbed energy were accordingly calculated as well. The specimens were fabricated from Kevlar, carbon, and glass woven fabrics and resin and were experimentally investigated under impact conditions. All the specimens possessed equal mass, shape, and density; nevertheless, the layers were ordered in different stacking sequence. After running the ballistic test at the same conditions, the final velocities of the cylindrical AISI 4340 Steel pellet showed how much energy was absorbed by the samples. The energy absorption of each sample through the ballistic impact was calculated; accordingly, the proper ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterise the material properties for the different layers.

  16. Hybrid Composite Laminates Reinforced with Kevlar/Carbon/Glass Woven Fabrics for Ballistic Impact Testing

    Directory of Open Access Journals (Sweden)

    Elias Randjbaran

    2014-01-01

    Full Text Available Current study reported a facile method to investigate the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption by running the ballistic test at the high velocity ballistic impact conditions. The velocity and absorbed energy were accordingly calculated as well. The specimens were fabricated from Kevlar, carbon, and glass woven fabrics and resin and were experimentally investigated under impact conditions. All the specimens possessed equal mass, shape, and density; nevertheless, the layers were ordered in different stacking sequence. After running the ballistic test at the same conditions, the final velocities of the cylindrical AISI 4340 Steel pellet showed how much energy was absorbed by the samples. The energy absorption of each sample through the ballistic impact was calculated; accordingly, the proper ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterise the material properties for the different layers.

  17. Structural Acoustic Response of a Shape Memory Alloy Hybrid Composite Panel (Lessons Learned)

    Science.gov (United States)

    Turner, Travis L.

    2002-01-01

    This study presents results from an effort to fabricate a shape memory alloy hybrid composite (SMAHC) panel specimen and test the structure for dynamic response and noise transmission characteristics under the action of thermal and random acoustic loads. A method for fabricating a SMAHC laminate with bi-directional SMA reinforcement is described. Glass-epoxy unidirectional prepreg tape and Nitinol ribbon comprise the material system. Thermal activation of the Nitinol actuators was achieved through resistive heating. The experimental hardware required for mechanical support of the panel/actuators and for establishing convenient electrical connectivity to the actuators is presented. Other experimental apparatus necessary for controlling the panel temperature and acquiring structural acoustic data are also described. Deficiency in the thermal control system was discovered in the process of performing the elevated temperature tests. Discussion of the experimental results focuses on determining the causes for the deficiency and establishing means for rectifying the problem.

  18. Highly efficient ultrasonic vibrothermography for detecting impact damage in hybrid composites

    Science.gov (United States)

    Derusova, D. A.; Vavilov, V. P.; Sfarra, S.; Sarasini, F.; Druzhinin, N. V.; Nekhoroshev, V. O.

    2017-05-01

    The use of wide frequency band piezoelectric transducers in ultrasonic infrared thermography allows analyzing material structural defects under low power ultrasonic stimulation compared to single-frequency stimulation which is performed, for example, by means of powerful magnetostrictive stimulation. Defect resonance frequencies can be determined through the detailed analysis of material surface vibrations by using a technique of laser vibrometry in a wide range of frequencies. This paper describes the approach to analyze ultrasonic resonances in samples with hidden defects by using resonant piezoelectric transducers. The effectiveness of the method is assessed by discussing some key examples of impact damaged graphite/epoxy composite samples hybridized with flax fibers. Optical and powerful ultrasonic stimulation have been also used as alternative inspection techniques.

  19. A novel organic-inorganic hybrid composition for controllably synthesizing AgI nanocrystals

    Science.gov (United States)

    Liu, Junxue; He, Sheng; An, Changhua; Zhang, Jun

    2017-05-01

    The ability to control the shape and morphology of semiconductor macro/nanocrystals is critical to applications such as photocatalysis, electrocatalysis, photonics and nanoelectronics. Despite significant advances in controlling the shapes by thermal decomposition and solvothermal methods, rigorous shape control by low temperature and aqueous phase controlling remains challenging. Herein, a facile synthetic method based on ethylenediamine assisted precursor transformation technique has been developed for the fabrication of AgI nanocrystals. The central features of our approach are the use of ethylenediamine (en) as complexant and the use of polyvinylpyrrolidone (PVP) as capping surfactants to form Ag(en)xI precursor, which is followed by removing en to form AgI crystals. This work provides new insights into the use of a novel organic-inorganic hybrid composition as precursors for nanocrystals synthesis and offers a potential route to achieve well-defined morphology of inorganic nanostructures with uniform shape and size.

  20. Electrical properties of NiO/PVC nano hybrid composites for organic field effect transistors

    Science.gov (United States)

    Hayati, A.; Bahari, A.

    2015-01-01

    In this study, NiO/PVC nano hybrid composites have been synthesized through sol-gel method. Nano crystallites phases, crystallinity and electrical properties have been characterized using X-ray diffraction, Fourier transfer infrared radiation, scanning electron microscopy and atomic force microscopy techniques. The dielectric constant of the samples has been calculated through measuring the capacity of samples by application of GPS 132 A. Obtained results have indicated that an NiO/PVC sample with 5 g NiO and 0.02 g PVC, equivalent to 0.4 %wt PVC, in weight synthesis, at a temperature of 80 °C has a higher dielectric constant, better surface morphology, less rough surface, less leakage current, and thus has potential to be suggested as a possible gate dielectric material for future organic field effect transistor devices.

  1. Nanoporous metal organic frameworks as hybrid polymer-metal composites for drug delivery and biomedical applications.

    Science.gov (United States)

    Beg, Sarwar; Rahman, Mahfoozur; Jain, Atul; Saini, Sumant; Midoux, Patrick; Pichon, Chantal; Ahmad, Farhan Jalees; Akhter, Sohail

    2017-04-01

    Metal organic frameworks (MOFs), porous hybrid polymer-metal composites at the nanoscale, are recent innovations in the field of chemistry; they are novel polymeric materials with diverse biomedical applications. MOFs are nanoporous materials, consisting of metal ions linked together by organic bridging ligands. The unique physical and chemical characteristics of MOFs have attracted wider attention from the scientific community, exploring their utility in the field of material science, biology, nanotechnology and drug delivery. The practical feasibility of MOFs is possible owing to their abilities for biodegradability, excellent porosity, high loading capacity, ease of surface modification, among others. In this regard, this review provides an account of various types of MOFs, their physiochemical characteristics and use in diverse disciplines of biomedical sciences - with special emphasis on drug delivery and theranostics. Moreover, this review also highlights the stability and toxicity issues of MOFs, along with their market potential for biomedical applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Multifunctional hybrids for electromagnetic absorption

    Energy Technology Data Exchange (ETDEWEB)

    Huynen, I. [Research Center in Micro and Nanoscopic Materials and Electronic Devices, CeRMiN, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Information and Communications Technologies, Electronics and Applied Mathematics (ICTEAM), Microwave Laboratory, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Quievy, N. [Institute of Condensed Matter and Nanosciences (IMCN), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Bailly, C. [Research Center in Micro and Nanoscopic Materials and Electronic Devices, CeRMiN, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Condensed Matter and Nanosciences (IMCN), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Mechanics, Materials and Civil Engineering (iMMC), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Bollen, P. [Information and Communications Technologies, Electronics and Applied Mathematics (ICTEAM), Microwave Laboratory, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Condensed Matter and Nanosciences (IMCN), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Mechanics, Materials and Civil Engineering (iMMC), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Detrembleur, C. [Center for Education and Research on Macromolecules (CERM), University of Liege, Sart-Tilman B6a, 4000 Liege (Belgium); Eggermont, S.; Molenberg, I. [Information and Communications Technologies, Electronics and Applied Mathematics (ICTEAM), Microwave Laboratory, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Thomassin, J.M.; Urbanczyk, L. [Center for Education and Research on Macromolecules (CERM), University of Liege, Sart-Tilman B6a, 4000 Liege (Belgium)

    2011-05-15

    Highlights: > EM absorption requires low dielectric constant and {approx}1 S/m electrical conductivity. > New hybrids were processed with CNT-filled polymer foam inserted in Al honeycomb. > The EM absorption in the GHz range is superior to any known material. > A closed form model is used to guide the design of the hybrid. > The architectured material is light with potential for thermal management. - Abstract: Electromagnetic (EM) interferences are ubiquitous in modern technologies and impact on the reliability of electronic devices and on living cells. Shielding by EM absorption, which is preferable over reflection in certain instances, requires combining a low dielectric constant with high electrical conductivity, which are antagonist properties in the world of materials. A novel class of hybrid materials for EM absorption in the gigahertz range has been developed based on a hierarchical architecture involving a metallic honeycomb filled with a carbon nanotube-reinforced polymer foam. The waveguide characteristics of the honeycomb combined with the performance of the foam lead to unexpectedly large EM power absorption over a wide frequency range, superior to any known material. The peak absorption frequency can be tuned by varying the shape of the honeycomb unit cell. A closed form model of the EM reflection and absorption provides a tool for the optimization of the hybrid. This designed material sets the stage for a new class of sandwich panels combining high EM absorption with mass efficiency, stiffness and thermal management.

  3. Field Testing and Load Rating Report for Bridge No. 4, Hybrid Composite Beam Span, at Fort Knox, Kentucky

    Science.gov (United States)

    2016-09-01

    metal guardrail as the military vehicles crossed the structure ; especially during the first tests run near the structure’s edges (Test Paths Y1 & Y3...were the first time these details were heavily loaded. In general, this type of behavior is common for newer structures and does not affect the...Composite Beams for Bridges for Project F12-AR15, “Corrosion-Resistant Hybrid Composite Bridge Beams for Structural Applications” Monitored by

  4. Thermo-mechanical performance of an ablative/ceramic composite hybrid thermal protection structure for re-entry applications

    OpenAIRE

    Triantou, K.; Mergia, K; Florez, S.; Perez, B.; Bárcena, Jorge; Rotärmel, W.; Pinaud, G.; Fischer, W.P.P.

    2015-01-01

    Hybrid thermal protection systems for aerospace applications based on ablative material (ASTERM (TM)) and ceramic matrix composite (SICARBON (TM)) have been investigated. The ablative material and the ceramic matrix composite were joined using graphite and zirconia zirconium silicate based commercial high temperature adhesives. The thermo-mechanical performance of the structures was assessed from room temperature up to 900 degrees C. In all the joints there is a decrease of shear strength wit...

  5. Al6061 Hybrid Metal Matrix Composite Reinforced with Alumina and Molybdenum Disulphide

    Directory of Open Access Journals (Sweden)

    G. Pitchayyapillai

    2016-01-01

    Full Text Available Aluminum Hybrid Reinforcement Technology is a response to the dynamic ever-increasing service requirement of industries such as transportation, aerospace, automobile, and marine, due to its attractive properties like high ductility, highly conductivity, light weight, and high strength to weight ratio. In this evolution, an attempt has been made to investigate the wear rate of Al6061 hybrid metal matrix composite reinforced with the hard ceramic alumina (4, 8, and 12 wt.% of Al2O3 and soft solid lubricant of molybdenum disulphide (2, 4, and 6 wt.% of MoS2 is fabricated by using stir casting method. The unlubricated pins on disc wear tests were conducted to examine the wear behaviour of Al6061/12 wt.% of Al2O3/MoS2 composites. The sliding wear tests were carried out at various loads of 15, 30, and 45 N, sliding velocity (1.25, 2.50, and 3.25 m/sec, and different MoS2 wt.% (2, 4, and 6 wt.%. In addition, the CNC turning experiments were conducted on Al6061/12 wt.% Al2O3/6 wt.% MoS2 using CNMG 120408 uncoated carbide cutting tool under cutting of 100, 150, and 200 m/min, feed of 0.1, 0.2, and 0.3 mm/rev, and depth of cut of 1, 1.5, and 2 mm.

  6. Compression After Impact Experiments and Analysis on Honeycomb Core Sandwich Panels with Thin Facesheets

    Science.gov (United States)

    McQuigg, Thomas D.

    2011-01-01

    A better understanding of the effect of impact damage on composite structures is necessary to give the engineer an ability to design safe, efficient structures. Current composite structures suffer severe strength reduction under compressive loading conditions, due to even light damage, such as from low velocity impact. A review is undertaken to access the current state-of-development in the areas of experimental testing, and analysis methods. A set of experiments on honeycomb core sandwich panels, with thin woven fiberglass cloth facesheets, is described, which includes detailed instrumentation and unique observation techniques.

  7. Static and Fatigue Characterization of Nomex Honeycomb Sandwich Panels

    Directory of Open Access Journals (Sweden)

    Keskes Boualem

    2013-07-01

    Full Text Available The main benefits of using the sandwich concept in structural components are the high stiffness, good fatigue resistance and low weight ratios. Recent advances in materials and construction techniques have resulted in further improvement and increased uniformity of the sandwich composite properties. In order to use these materials in different applications, the knowledge of simply their static properties alone is not sufficient but additional information on their fatigue properties and durability are required. In this paper, first static and fatigue tests on four points bending of nomex honeycomb composite sandwich panels have been performed. Load/displacement and S-N fatigue curves are presented and analysed. Fatigue failure and damage modes are observed with an optical microscope and are discussed. The second is to address such fatigue behaviour by using a damage model and check it by experimentation. This fatigue damage model is based on stiffness degradation, which is used as a damage indicator. Two non-linear cumulative damage models derived from the chosen stiffness degradation equation are examined with assumption of linear Miner's damage summation. Predicted results are compared with available experimental data.

  8. Static and Fatigue Characterization of Nomex Honeycomb Sandwich Panels

    Directory of Open Access Journals (Sweden)

    Keskes Boualem

    2013-07-01

    Full Text Available The main benefits of using the sandwich concept in structural components are the high stiffness, good fatigue resistance and low weight ratios. Recent advances in materials and construction techniques have resulted in further improvement and increased uniformity of the sandwich composite properties. In order to use these materials in different applications, the knowledge of simply their static properties alone is not sufficient but additional information on their fatigue properties and durability are required. In this paper, first static and fatigue tests on four points bending of nomex honeycomb composite sandwich panels have been performed. Load/displacement and S-N fatigue curves are presented and analysed. Fatigue failure and damage modes are observed with an optical microscope and are discussed. The second is to address such fatigue behaviour by using a damage model and check it by experimentation. This fatigue damage model is based on stiffness degradation, which is used as a damage indicator. Two non-linear cumulative damage models derived from the chosen stiffness degradation equation are examined with assumption of linear Miner's damage summation. Predicted results are compared with available experimental data.

  9. Evaluation of Internal Defect of Composite Laminates Using A Novel Hybrid Laser Generation/Air-Coupled Detection Ultrasonic System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joon Hyun; Lee, Seung Joon [Pusan National University, Busan (Korea, Republic of); Byun, Joon Hyung [KIMM, Daejeon (Korea, Republic of)

    2008-02-15

    Ultrasonic C-scan technique is one of very popular techniques being used for detection of flaws in polymer matrix composite(PMC). However, the application of this technique is very limited for evaluation of defects in PMC fabricated by the automated fiber placement process. The purpose of this study is to develop a novel ultrasonic hybrid system based on nondestructive and non-contact ultrasonic techniques for evaluation of delamination in carbon/epoxy and carbon/PPS composite laminates. It was shown that the newly developed ultrasonic hybrid system based on dual air-coupled pitch-catch technique with ultrasonic scattering reflection concept could provide excellent image with higher resolution of delamination in PMC compared with the conventional pitch-catch method. It is expected that this ultrasonic hybrid technique can be applied for on-line inspection of flaws in PMC during the fabrication process

  10. Optimizing Thermal-Elastic Properties of C/C–SiC Composites Using a Hybrid Approach and PSO Algorithm

    Directory of Open Access Journals (Sweden)

    Yingjie Xu

    2016-03-01

    Full Text Available Carbon fiber-reinforced multi-layered pyrocarbon–silicon carbide matrix (C/C–SiC composites are widely used in aerospace structures. The complicated spatial architecture and material heterogeneity of C/C–SiC composites constitute the challenge for tailoring their properties. Thus, discovering the intrinsic relations between the properties and the microstructures and sequentially optimizing the microstructures to obtain composites with the best performances becomes the key for practical applications. The objective of this work is to optimize the thermal-elastic properties of unidirectional C/C–SiC composites by controlling the multi-layered matrix thicknesses. A hybrid approach based on micromechanical modeling and back propagation (BP neural network is proposed to predict the thermal-elastic properties of composites. Then, a particle swarm optimization (PSO algorithm is interfaced with this hybrid model to achieve the optimal design for minimizing the coefficient of thermal expansion (CTE of composites with the constraint of elastic modulus. Numerical examples demonstrate the effectiveness of the proposed hybrid model and optimization method.

  11. Synthesis and Properties of Cellulose-Functionalized POSS-SiO2/TiO2 Hybrid Composites.

    Science.gov (United States)

    Hong, Gwang-Wook; Ramesh, Sivalingam; Kim, Joo-Hyung; Kim, Hyeon-Ju; Lee, Ho-Saeng

    2015-10-01

    The mechanical, thermal, optical, electrical and morphological properties of cellulose, an excellent natural biomaterial, can be improved by organic-inorganic hybrid composite methods. Based on the pristine properties of cellulose, the preparation of cellulose-metal oxide hybrid nanocomposites using a dispersion process of nanoparticles into the cellulose host matrix by traditional methods, has limitations. Recently, the functionalized cellulose-polymer-based materials were considered to be an important class of high-performance materials, providing the synthesis of various functional hybrid nanocomposites using a sol-gel method. Transparent cellulose-POSS-amine-silica/titania hybrids were prepared by an in-situ sol-gel process in the presence of γ-aminopropyltrimethoxylsilane (γ-APTES). The methodology involves the formation of covalent bonding between the cellulose-POSS amine and SiO2/TiO2 hybrid nanocomposite material. An analysis of the synthesized hybrid material by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, differential thermal calorimetry, scanning electron microscopy, and transmission electron microscopy indicated that the silica/titania nanoparticles were bonded covalently and dispersed uniformly into the cellulose-POSS amine matrix. In addition, biological properties of the cellulose-POSS-silica/titania hybrid material were examined using an antimicrobial test against pathogenic bacteria, such as Bacillus cereus (F481072) and E. coli (ATCC35150) for the bacterial effect.

  12. 49 CFR 587.15 - Verification of aluminum honeycomb crush strength.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Verification of aluminum honeycomb crush strength... Deformable Barrier § 587.15 Verification of aluminum honeycomb crush strength. The following procedure is used to ascertain the crush strength of the main honeycomb block and the bumper element honeycomb,...

  13. Studies on the chemical resistance and mechanical properties of natural polyalthia cerasoides woven fabric/glass hybridized epoxy composites

    CSIR Research Space (South Africa)

    Jayaramudu, J

    2015-01-01

    Full Text Available In the present work, natural Polyalthiacerasoide woven fabrics were extracted from the bark of the tree and using these woven fabrics/glass fibre as reinforcements and epoxy as matrix the hybrid composites were prepared by the hand lay-up technique...

  14. Tensile Mechanical Properties and Strengthening Mechanism of Hybrid Carbon Nanotube and Silicon Carbide Nanoparticle-Reinforced Magnesium Alloy Composites

    National Research Council Canada - National Science Library

    Zhou, Xia; Su, Depeng; Wu, Chengwei; Liu, Liming

    2012-01-01

    .... The results showed that grains of the matrix in the AZ91/(CNT + SiC) composites were obviously refined after adding hybrid CNTs and SiC nanoparticles to the AZ91 alloy, and the room-temperature mechanical properties of AZ91/(CNT + SiC...

  15. Direct electrochemistry of horseradish peroxidase immobilized on the layered calcium carbonate-gold nanoparticles inorganic hybrid composite.

    Science.gov (United States)

    Li, Feng; Feng, Yan; Wang, Zhen; Yang, Limin; Zhuo, Linhai; Tang, Bo

    2010-06-15

    A mediator-free hydrogen peroxide (H(2)O(2)) biosensor was fabricated based on immobilization of horseradish peroxidase (HRP) on layered calcium carbonate-gold nanoparticles (CaCO(3)-AuNPs) inorganic hybrid composite. The proposed biosensor showed a strong electrocatalytic activity toward the reduction of H(2)O(2), which could be attributed to the favored orientation of HRP in the well-confined surface as well as the high electrical conductivity of the resulting CaCO(3)-AuNPs inorganic hybrid composite. The hybrid composite was obtained by the adsorption of AuNPs onto the surfaces of layered CaCO(3) through electrostatic interaction. The key analytical parameters relative to the biosensor performance such as pH and applied potential were optimized. The developed biosensor also exhibited a fast amperometric response (3s), a good linear response toward H(2)O(2) over a wide range of concentration from 5.0x10(-7) to 5.2x10(-3)M, and a low detection limit of 1.0x10(-7)M. The facile, inexpensive and reliable sensing platform based on layered CaCO(3)-AuNPs inorganic hybrid composite should hold a huge potential for the fabrication of more other biosensors.

  16. Variability in fatty acid and triacylglycerol composition of the oil of coconut (Cocos nucifera L.) hybrids and their parentals.

    Science.gov (United States)

    Laureles, Lucita R; Rodriguez, Felicito M; Reaño, Consorcia E; Santos, Gerardo A; Laurena, Antonio C; Mendoza, Evelyn Mae Tecson

    2002-03-13

    The fatty acid profiles and triacylglycerol (TAG) compositions of oils from the solid endosperm of different Philippine coconut hybrids and their parentals were determined by using gas chromatography (GC) and high-performance liquid chromatography (HPLC). In general, varietal differences in fatty acid composition were observed. Lauric acid (C12) content was significantly higher in the hybrids PCA 15-8 (50.45%) and PCA 15-9 (50.26%) by about 3.16% points as compared to other hybrids, and higher in Tacunan Green Dwarf (50.50%) among the parentals. Among the fatty acids, lauric acid exhibited the least variation. In general, none of the hybrids had higher fatty acid content than their parentals. The HPLC chromatogram of triacylglycerols (TAG) showed 8 major peaks which differ in carbon number (CN) by two: identified as TAG CN 30, 32, 34, 36, 38, 40, 42, and 44. TAGs CN 30 (4.08%) and CN 34 (19.20%) were found to be significantly higher in PCA 15-9 than in the other hybrids. CN 36 was highest (21.94-23.66%) in all hybrids and parentals. The TAG CNs varied significantly among hybrids and parents, i.e., in CN 30, 32, and 34, which are high in medium chain triacylglycerols (MCTs), and in CN 30 (for parentals only), 40, 42, and 44 (the latter two for parentals only), and none in CN 36. MCTs calculated for two hybrids and their parents ranged from 13.81% to 20.55%.

  17. Hot Extrusion of A356 Aluminum Metal Matrix Composite with Carbon Nanotube/Al2O3 Hybrid Reinforcement

    Science.gov (United States)

    Kim, H. H.; Babu, J. S. S.; Kang, C. G.

    2014-05-01

    Over the years, the attention of material scientists and engineers has shifted from conventional composite materials to nanocomposite materials for the development of light weight and high-performance devices. Since the discovery of carbon nanotubes (CNTs), many researchers have tried to fabricate metal matrix composites (MMCs) with CNT reinforcements. However, CNTs exhibit low dispersibility in metal melts owing to their poor wettability and large surface-to-volume ratio. The use of an array of short fibers or hybrid reinforcements in a preform could overcome this problem and enhance the dispersion of CNTs in the matrix. In this study, multi-walled CNT/Al2O3 preform-based aluminum hybrid composites were fabricated using the infiltration method. Then, the composites were extruded to evaluate changes in its mechanical properties. In addition, the dispersion of reinforcements was investigated using a hardness test. The required extrusion pressure of hybrid MMCs increased as the Al2O3/CNT fraction increased. The deformation resistance of hybrid material was over two times that of the original A356 aluminum alloy material due to strengthening by the Al2O3/CNTs reinforcements. In addition, an unusual trend was detected; primary transition was induced by the hybrid reinforcements, as can be observed in the pressure-displacement curve. Increasing temperature of the material can help increase formability. In particular, temperatures under 623 K (350 °C) and over-incorporating reinforcements (Al2O3 20 pct, CNTs 3 pct) are not recommended owing to a significant increase in the brittleness of the hybrid material.

  18. Flexural Behavior of Aluminum Honeycomb Core Sandwich Structure

    Science.gov (United States)

    Matta, Vidyasagar; Kumar, J. Suresh; Venkataraviteja, Duddu; Reddy, Guggulla Bharath Kumar

    2017-05-01

    This project is concerned with the fabrication and flexural testing of aluminium honey comb sandwich structure which is a special case of composite materials that is fabricated by attaching two thin but stiff skins to a light weight but thick core. The core material is normally low density material but its high thickness provide the sandwich composite with high bonding stiffness. Honeycomb core are classified into two types based on the materials and structures. Hexagonal shape has a unique properties i.e has more bonding strength and less formation time based on the cell size and sheet thickness. Sandwich structure exhibit different properties such as high load bearing capacity at low weight and has excellent thermal insulation. By considering the above properties it has tendency to minimize the structural problem. So honey comb sandwich structure is choosed. The core structure has a different applications such as aircraft, ship interiors, construction industries. As there is no proper research on strength characteristics of sandwich structure. So, we use light weight material to desire the strength. There are different parameters involved in this structure i.e cell size, sheet thickness and core height. In this project we considered 3 level of comparison among the 3 different parameters cell size of 4, 6 and 8 mm, sheet thickness of 0.3, 0.5 and 0.7 mm, and core height of 20,25 and 30 mm. In order to reduce the number of experiment we use taguchi design of experiment, and we select the L8 orthogonal array is the best array for this type of situation, which clearly identifies the parameters by independent of material weight to support this we add the minitab software, to identify the main effective plots and regression equation which involves the individual response and corresponding parameters. Aluminium material is used for the fabrication of Honeycomb sandwich structure among the various grades of aluminium we consider the AL6061 which is light weight material

  19. Relationship between the degree of conversion, solubility and salivary sorption of a hybrid and a nanofilled resin composite

    Directory of Open Access Journals (Sweden)

    Eduardo Moreira da Silva

    2008-04-01

    Full Text Available This study analyzed the relationship between the degree of conversion (DC, solubility, and salivary sorption of a hybrid (Filtek P 60 and a nanofilled resin composite (Filtek Supreme, and evaluated the influence of the light-activation mode on these properties. Two light-activation modes were used: Conventional (C; 850 mW/cm² for 20 s and Soft-start (SS; 100-1,000 mW/cm² for 10 s + 1,000 mW/cm² for 10 s. The DC (% was evaluated by FT-Raman spectroscopy. The solubility and salivary sorption were measured after immersion in artificial saliva for 7 days. Data were analyzed by ANOVA and Student-Newman-Keuls' test and linear regression analysis (a = 0.05. The DC varied from 50.52% (nanofilled composite to 57.15% (hybrid composite, and was influenced by the light-activation mode: C > SS. The solubility (0.45 mg/mm³ and salivary sorption (8.04 mg/mm³ of the nanofilled composite were greater than those of the hybrid composite (0.40 mg/mm³ / 6.87 mg/mm³, and were influenced by the light-activation mode: SS > C. Correlation was found between DC and solubility (r = - 0.89, p<0.05, as well as between solubility and salivary sorption (r = 0.95. These findings suggest that nanofilled composites may present higher degradation in the oral environment than hybrid ones. Soft-start light-activation mode may increase the solubility of resin composites.

  20. Wear Characteristics of Hybrid Composites Based on Za27 Alloy Reinforced With Silicon Carbide and Graphite Particles

    Directory of Open Access Journals (Sweden)

    S. Mitrović

    2014-06-01

    Full Text Available The paper presents the wear characteristics of a hybrid composite based on zinc-aluminium ZA27 alloy, reinforced with silicon-carbide and graphite particles. The tested sample contains 5 vol.% of SiC and 3 vol.% Gr particles. Compocasting technique has been used to prepare the samples. The experiments were performed on a “block-on-disc” tribometer under conditions of dry sliding. The wear volumes of the alloy and the composite were determined by varying the normal loads and sliding speeds. The paper contains the procedure for preparation of sample composites and microstructure of the composite material and the base ZA27 alloy. The wear surface of the composite material was examined using the scanning electronic microscope (SEM and energy dispersive spectrometry (EDS. Conclusions were obtained based on the observed impact of the sliding speed, normal load and sliding distance on tribological behaviour of the observed composite.

  1. The Effect of Lamina Intraply Hybrid Composites on the Tensile Properties of Various Weave Designs

    Science.gov (United States)

    Yuhazri, M. Y.; Amirhafizan, M. H.; Abdullah, A.; Sihombing, H.; Nirmal, U.; Saarah, A. B.; Fadzol, O. M.

    2016-11-01

    The topic of natural fiber is one of the most active areas in thermoset composite research today. This paper will focuses on the effect of weave designs on the mechanical behaviour of lamina intraply hybrid composites. Twelve specimens were used and they were made of kenaf fibre and glass fibre as a reinforcement and unsaturated polyester resin as a matrix in various weave designs which were plain, twill, satin, basket, mock leno, and leno weave. Vacuum infusion technique was used due to its superior advantages over hand lay-up. The specimens were produced in two types which were kenaf fibre in warp direction interlace with glass fibre in weft direction (WK-WG) and glass fibre in warp direction interlace with kenaf fibre in weft direction (WG-WK). Various weave designs were found to affect the tensile properties. Glass fibre in warp direction has a greater effect on tensile strength compared to kenaf fibre in warp direction. Mock leno weave exhibited better mechanical properties for WK-WG and WG-WK, about 54.74 MPa and 99.46 MPa respectively.

  2. Spin-triplet electron transport in hybrid superconductor heterostructures with a composite ferromagnetic interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Sheyerman, A. E., E-mail: karen@hitech.cplire.ru; Constantinian, K. Y.; Ovsyannikov, G. A.; Kislinskii, Yu. V.; Shadrin, A. V. [Russian Academy of Sciences, Kotelnikov Institute of Radio Engineering and Electronics (Russian Federation); Kalabukhov, A. V. [Chalmers University of Technology (Sweden); Khaydukov, Yu. N. [Max-Planck Institute for Solid State Research (Germany)

    2015-06-15

    Hybrid YBa{sub 2}Cu{sub 3}O{sub 7−x}/SrRuO{sub 3}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/Au-Nb superconductor mesastructures with a composite manganite-ruthenate ferromagnetic interlayer are studied using electrophysical, magnetic, and microwave methods. The supercurrent in the mesastructure is observed when the interlayer thickness is much larger than the coherence length of ferromagnetic materials. The peak on the dependence of the critical current density on the interlayer material thickness corresponds to the coherence length, which is in qualitative agreement with theoretical predictions for a system with spit-triplet superconducting correlations. The magnetic-field dependence of the critical current is determined by penetration of magnetic flux quanta and by the magnetic domain structure, as well as by the field dependence of disorientation of the magnetization vectors of the layers in the composite magnetic interlayer. It is found that the supercurrent exists in magnetic fields two orders of magnitude stronger than the field corresponding to entry of a magnetic flux quantum into the mesastructure. The current-phase relation (CPR) of the supercurrent of mesastructures is investigated upon a change in the magnetic field from zero to 30 Oe; the ratio of the second CPR harmonic to the first, determined from the dependence of the Shapiro steps on the microwave radiation amplitude, does not exceed 50%.

  3. Polysiloxane/PVA-glutaraldehyde hybrid composite as solid phase for immunodetections by ELISA

    Directory of Open Access Journals (Sweden)

    A.E. Lima Barros

    2002-04-01

    Full Text Available We developed an efficient method to prepare a hybrid inorganic-organic composite based on polyvinyl alcohol (PVA and polysiloxane using the sol-gel disc technique. Antigen obtained from Yersinia pestis was covalently immobilized onto these discs with glutaraldehyde and used as solid phase in ELISA for antibody detection in serum of rabbits experimentally immunized with plague. Using 1.25 µg antigen per disc, a peroxidase conjugate dilution of 1:4,000 and a serum dilution of 1:200 were adequate for the establishment of the procedure. These values are similar to those used for PVA-glutaraldehyde discs, plasticized filter paper discs and the polyaniline-Dacron composite discs. This procedure is comparable to that which utilizes the adsorption of the antigen to conventional PVC plates, with the amount of antigen being one fourth that employed in conventional PVC plates (5 µg/well. In addition to the performance of the polysiloxane/PVA-glutaraldehyde disc as a matrix for immunodetection, its easy synthesis and low cost are additional advantages for commercial application.

  4. Sequential fault diagnosis for mechatronics system using diagnostic hybrid bond graph and composite harmony search

    Directory of Open Access Journals (Sweden)

    Ming Yu

    2015-12-01

    Full Text Available This article proposes a sequential fault diagnosis method to handle asynchronous distinct faults using diagnostic hybrid bond graph and composite harmony search. The faults under consideration include fault mode, abrupt fault, and intermittent fault. The faults can occur in different time instances, which add to the difficulty of decision making for fault diagnosis. This is because the earlier occurred fault can exhibit fault symptom which masks the fault symptom of latter occurred fault. In order to solve this problem, a sequential identification algorithm is developed in which the identification task is reactivated based on two conditions. The first condition is that the latter occurred fault has at least one inconsistent coherence vector element which is consistent in coherence vector of the earlier occurred fault, and the second condition is that the existing fault coherence vector has the ability to hide other faults and the second-level residual exceeds the threshold. A new composite harmony search which is capable of handling continuous variables and binary variables simultaneously is proposed for identification purpose. Experiments on a mobile robot system are conducted to assess the proposed sequential fault diagnosis algorithm.

  5. Preparation and characterization of functional material based on hybrid polymer composites

    Science.gov (United States)

    Agusu, La; Amiruddin; Taswito, Chen Chen; Herdianto; Zamrun, Muh.

    2016-08-01

    The microstructures and properties of hybrid polymer composites based on polyaniline (PANi)/γ-Fe2O3 nanoparticles/TiO2/carbon have been investigated for multifunctional applications such as heavy metal removal and initial study for radar absorbing material application. γ-Fe2O3 nanoparticles with spherical shape were synthetized by a coprecipitation method from iron sand. By activating the polyethylene glycol (PEG-400) coated carbon of coconut shell, the homogenous shape and size of carbon was achieved. Then, γ- Fe2O3, TiO2, and carbon were mixed with PANi by an in situ polymerization method at low temperature 0-5 oC. Characterization process involved XRD, SEM, FTIR, VSM, and DC conductivity measurements. For radar absorber application, the functionalized polymer composites showed good electrical conductivity 0.45 S/cm to absorb the incoming electromagnetic energy. An efficient and effective reduction of Pb2+ ion from the water has been achieved by using this material.

  6. A hybrid matching method for geospatial services in a composition-oriented environment

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    With the development of Internet and GIS,large volumes of spatial data,powerful computing resources and many spatial data processing functions are published in the form of Web services.Finding suitable geospatial services in the composition-oriented environment is a crucial task.The semantic Web provides a kind of technology to find and compose various service resources automatically through the Web.This paper proposes a hybrid method for the semantic matching of geospatial services.The method includes two parts.Part 1 puts forward a multi-level semantic matching approach,which matches single geospatial service at four levels:classification,input/output,precondition/effect and the quality of service(QoS).This multi-level matching approach makes single service matching quicker and more accurate.Part 2 puts forward a matching algorithm for a geospatial service chain based on the context.The algorithm adopts a trace algorithm,taking account of the effect of the context.It restricts the input/output parameters of the current service by the input/output parameters of service chain,pre-service and sub-service.It matches the atomic service dynamically in a composition-oriented environment,and accurately converts the abstract model of geospatial services into an executable geospatial service chain.A case study of the flood analysis for the Poyang Lake illustrates the effectiveness of our context-based matching method for geospatial services.

  7. Design, fabrication, and testing of a SMA hybrid composite jet engine chevron

    Science.gov (United States)

    Turner, Travis L.; Cabell, Randolph H.; Cano, Roberto J.; Fleming, Gary A.

    2006-01-01

    Control of jet noise continues to be an important research topic. Exhaust nozzle chevrons have been shown to reduce jet noise, but parametric effects are not well understood. Additionally, thrust loss due to chevrons at cruise suggests significant benefit from deployable chevrons. The focus of this study is development of an active chevron concept for the primary purpose of parametric studies for jet noise reduction in the laboratory and technology development to leverage for full scale systems. The active chevron concept employed in this work consists of a laminated composite structure with embedded shape memory alloy (SMA) actuators, termed a SMA hybrid composite (SMAHC). The actuators are embedded on one side of the middle surface such that thermal excitation generates a moment and deflects the structure. A brief description of the chevron design is given followed by details of the fabrication approach. Results from bench top tests are presented and correlated with numerical predictions from a model for such structures that was recently implemented in MSC.Nastran and ABAQUS. Excellent performance and agreement with predictions is demonstrated. Results from tests in a representative flow environment are also presented. Excellent performance is again achieved for both open- and closed-loop tests, the latter demonstrating control to a specified immersion into the flow. The actuation authority and immersion performance is shown to be relatively insensitive to nozzle pressure ratio (NPR). Very repeatable immersion control with modest power requirements is demonstrated.

  8. Analysis of SMA Hybrid Composite Structures in MSC.Nastran and ABAQUS

    Science.gov (United States)

    Turner, Travis L.; Patel, Hemant D.

    2005-01-01

    A thermoelastic constitutive model for shape memory alloy (SMA) actuators and SMA hybrid composite (SMAHC) structures was recently implemented in the commercial finite element codes MSC.Nastran and ABAQUS. The model may be easily implemented in any code that has the capability for analysis of laminated composite structures with temperature dependent material properties. The model is also relatively easy to use and requires input of only fundamental engineering properties. A brief description of the model is presented, followed by discussion of implementation and usage in the commercial codes. Results are presented from static and dynamic analysis of SMAHC beams of two types; a beam clamped at each end and a cantilever beam. Nonlinear static (post-buckling) and random response analyses are demonstrated for the first specimen. Static deflection (shape) control is demonstrated for the cantilever beam. Approaches for modeling SMAHC material systems with embedded SMA in ribbon and small round wire product forms are demonstrated and compared. The results from the commercial codes are compared to those from a research code as validation of the commercial implementations; excellent correlation is achieved in all cases.

  9. Hybrid-Wing-Body Vehicle Composite Fuselage Analysis and Case Study

    Science.gov (United States)

    Mukhopadhyay, Vivek

    2014-01-01

    Recent progress in the structural analysis of a Hybrid Wing-Body (HWB) fuselage concept is presented with the objective of structural weight reduction under a set of critical design loads. This pressurized efficient HWB fuselage design is presently being investigated by the NASA Environmentally Responsible Aviation (ERA) project in collaboration with the Boeing Company, Huntington Beach. The Pultruded Rod-Stiffened Efficient Unitized Structure (PRSEUS) composite concept, developed at the Boeing Company, is approximately modeled for an analytical study and finite element analysis. Stiffened plate linear theories are employed for a parametric case study. Maximum deflection and stress levels are obtained with appropriate assumptions for a set of feasible stiffened panel configurations. An analytical parametric case study is presented to examine the effects of discrete stiffener spacing and skin thickness on structural weight, deflection and stress. A finite-element model (FEM) of an integrated fuselage section with bulkhead is developed for an independent assessment. Stress analysis and scenario based case studies are conducted for design improvement. The FEM model specific weight of the improved fuselage concept is computed and compared to previous studies, in order to assess the relative weight/strength advantages of this advanced composite airframe technology

  10. Measurement and Prediction of the Thermomechanical Response of Shape Memory Alloy Hybrid Composite Beams

    Science.gov (United States)

    Davis, Brian; Turner, Travis L.; Seelecke, Stefan

    2005-01-01

    Previous work at NASA Langley Research Center (LaRC) involved fabrication and testing of composite beams with embedded, pre-strained shape memory alloy (SMA) ribbons within the beam structures. That study also provided comparison of experimental results with numerical predictions from a research code making use of a new thermoelastic model for shape memory alloy hybrid composite (SMAHC) structures. The previous work showed qualitative validation of the numerical model. However, deficiencies in the experimental-numerical correlation were noted and hypotheses for the discrepancies were given for further investigation. The goal of this work is to refine the experimental measurement and numerical modeling approaches in order to better understand the discrepancies, improve the correlation between prediction and measurement, and provide rigorous quantitative validation of the numerical analysis/design tool. The experimental investigation is refined by a more thorough test procedure and incorporation of higher fidelity measurements such as infrared thermography and projection moire interferometry. The numerical results are produced by a recently commercialized version of the constitutive model as implemented in ABAQUS and are refined by incorporation of additional measured parameters such as geometric imperfection. Thermal buckling, post-buckling, and random responses to thermal and inertial (base acceleration) loads are studied. The results demonstrate the effectiveness of SMAHC structures in controlling static and dynamic responses by adaptive stiffening. Excellent agreement is achieved between the predicted and measured results of the static and dynamic thermomechanical response, thereby providing quantitative validation of the numerical tool.

  11. Tartaric Acid-Assisted Self-Assembly of Hybrid Block Copolymer Composites

    Science.gov (United States)

    Yao, Li; Lin, Ying; Watkins, James

    2014-03-01

    Enantiopure tartaric acid was used as an additive to increase the segregation strength of poly(ethylene oxide-block-tert-butyl acrylate) (PEO-b-PtBA) copolymers through strong, selective interactions with one of the polymer chain segments. Addition of tartaric acid to PEO-b-PtBA exhibiting cylindrical morphologies resulted in the formation of helical superstructures as observed by transmission electron microscopy. It was also found that this small acid additive can also enable phase-selective ultra-high loading of nanoparticles (NPs) into target domains of the block copolymer composites. The loading of tartaric acid can increase enthalpically favorable interactions between the nanoparticle ligands and the host domain and mitigate entropic penalties associated with NP incorporation into the target domain. A metal content of over 40 weight percent by mass of the resulting well ordered composites was achieved as measured by thermal gravimetric analysis in PEO-b-PtBA/tartaric acid/4-hydroxythiophenol functionalized Au NP hybrid system. Funding from Center for Hierarchical Manufacturing (CHM); Facility support from Materials Research Science and Engineering Center at UMass Amherst.

  12. Structural considerations in friction welding of hybrid Al2O3-reinforced aluminum composites

    Institute of Scientific and Technical Information of China (English)

    In-Duck PARK; Choon-Tae LEE; Hyur-Soo KIM; Woo-Jin CHOI; Myung-Chang KANG

    2011-01-01

    Comparative studies on the relationship between the welding parameters and joining efficiency in the friction welding of hybrid Al2O3-reinforced aluminum composites were conducted. Metal matrix composites (MMCs) with 37% (volume fraction)aluminum particle were joined by friction welding. The results show that the effects of the rotation speed on the reduction rate of particle size are greater than those of the upset pressure, and the area of the MMC weld zone decreases as the joining efficiency increases, while it is considered that the joining efficiency does not increase as the reduction rate of particle size decreases. During the macro-examination of the bonding interface. a gray discolored region was observed on the bonding interface, and the center of the region was dark gray. After the micro-examination of the bonding interface, base metal made some second particulate formed by condensed alumina particulate but discoloration part distributed minute alumina particulate without second particulate. Consequently,it was also observed that rotational speed of 3 000 r/min and upset pressure of 63.6 MPa showed a very good joint.

  13. World Automata: a compositional approach to model implicit communication in hierarchical Hybrid Systems

    Directory of Open Access Journals (Sweden)

    Marta Capiluppi

    2013-08-01

    Full Text Available We propose an extension of Hybrid I/O Automata (HIOAs to model agent systems and their implicit communication through perturbation of the environment, like localization of objects or radio signals diffusion and detection. The new object, called World Automaton (WA, is built in such a way to preserve as much as possible of the compositional properties of HIOAs and its underlying theory. From the formal point of view we enrich classical HIOAs with a set of world variables whose values are functions both of time and space. World variables are treated similarly to local variables of HIOAs, except in parallel composition, where the perturbations produced by world variables are summed. In such way, we obtain a structure able to model both agents and environments, thus inducing a hierarchy in the model and leading to the introduction of a new operator. Indeed this operator, called inplacement, is needed to represent the possibility of an object (WA of living inside another object/environment (WA.

  14. Damping capacity in shape memory alloy honeycomb structures

    Science.gov (United States)

    Boucher, M.-A.; Smith, C. W.; Scarpa, F.; Miller, W.; Hassan, M. R.

    2010-04-01

    SMA honeycombs have been recently developed by several Authors [1, 2] as innovative cellular structures with selfhealing capability following mechanical indentation, unusual deformation (negative Poisson's ratio [3]), and possible enhanced damping capacity due to the natural vibration dissipation characteristics of SMAs under pseudoelastic and superelastic regime. In this work we describe the nonlinear damping effects of novel shape memory alloy honeycomb assemblies subjected to combine mechanical sinusoidal and thermal loading. The SMA honeycomb structures made with Ni48Ti46Cu6 are designed with single and two-phase polymeric components (epoxy), to enhance the damping characteristics of the base SMA for broadband frequency vibration.

  15. Crystallography of rare galactic honeycomb structure near supernova 1987a

    Science.gov (United States)

    Noever, David A.

    1994-01-01

    Near supernova 1987a, the rare honeycomb structure of 20-30 galactic bubbles measures 30 x 90 light years. Its remarkable regularity in bubble size suggests a single-event origin which may correlate with the nearby supernova. To test the honeycomb's regularity in shape and size, the formalism of statistical crystallography is developed here for bubble sideness. The standard size-shape relations (Lewis's law, Desch's law, and Aboav-Weaire's law) govern area, perimeter and nearest neighbor shapes. Taken together, they predict a highly non-equilibrium structure for the galactic honeycomb which evolves as a bimodal shape distribution without dominant bubble perimeter energy.

  16. CHEMICAL COMPOSITION AND IN VITRO FERMENTATION OF SILAGES FROM DIFFERENT SORGHUM HYBRIDS CULTIVATED IN THREE PILOT FARMS

    Directory of Open Access Journals (Sweden)

    Mirko Cattani

    2015-09-01

    Full Text Available This experiment compared silages obtained from ten hybrids of sorghum grown in three farms of the Po Valley, in terms of in vitro degradability, gas production (GP, and energy value. Hybrids were sown on 30 experimental plots (three plots per each hybrid, harvested at late-milk stage of maturity and ensiled for 60 d into 30 mini-silos (3 silos×10 hybrids. After ensiling, silages were analyzed for proximate composition, pH, ammonia N, and fermentation acid profile. Degradability of NDF (NDFd and of true dry matter (TDMd was determined after 48 h of incubation using sequentially DaisyII incubator and Ankom220 Fibre Analyzer. Two incubation runs (at 48 h were carried out to evaluate in vitro GP of silages, and to estimate their energy content. All data were submitted to ANOVA considering “hybrid” and “farm” as sources of variation. The interaction between hybrid and farm was never significant and it was excluded from the statistical model. The contents of dry matter and NDF of silages were influenced by hybrid and farm (P<0.05. In vitro parameters (NDFd after 48 h and GP at 24 and 48 h of incubation were influenced by hybrid and farm (P<0.001 and P<0.01 respectively. Among hybrids and farms, large differences (P<0.001 were also found out as regard to net energy content of sorghum silages. Because of this large variability, sorghum silages can be included successfully in ruminant diets considering the peculiarities of each hybrid with respect to the energy requirements of dairy cows.

  17. Simulation of the honeycomb construction process

    Science.gov (United States)

    Yuanzhang, Zhang

    2010-06-01

    The construction process of the honeycomb by bees is an astonishing process. The original structure which the bees built is nothing more than a lot of rough cylinders. But keeping the beeswax semi-flow for a certain time, those rough structures become perfect hexahedral columns. A modified, simplified particle method was used here to simulate the semi-flow state of the material. Although the parameters used here were still rather subjective, the simulation still could demonstrate some behavior of that sort of material like beeswax. And the method that the bees used to build their honey comb, could be an efficient method to imitate when we are trying to manufacture cellular materials.

  18. Compression After Impact on Honeycomb Core Sandwich Panels with Thin Facesheets, Part 2: Analysis

    Science.gov (United States)

    Mcquigg, Thomas D.; Kapania, Rakesh K.; Scotti, Stephen J.; Walker, Sandra P.

    2012-01-01

    A two part research study has been completed on the topic of compression after impact (CAI) of thin facesheet honeycomb core sandwich panels. The research has focused on both experiments and analysis in an effort to establish and validate a new understanding of the damage tolerance of these materials. Part 2, the subject of the current paper, is focused on the analysis, which corresponds to the CAI testings described in Part 1. Of interest, are sandwich panels, with aerospace applications, which consist of very thin, woven S2-fiberglass (with MTM45-1 epoxy) facesheets adhered to a Nomex honeycomb core. Two sets of materials, which were identical with the exception of the density of the honeycomb core, were tested in Part 1. The results highlighted the need for analysis methods which taken into account multiple failure modes. A finite element model (FEM) is developed here, in Part 2. A commercial implementation of the Multicontinuum Failure Theory (MCT) for progressive failure analysis (PFA) in composite laminates, Helius:MCT, is included in this model. The inclusion of PFA in the present model provided a new, unique ability to account for multiple failure modes. In addition, significant impact damage detail is included in the model. A sensitivity study, used to assess the effect of each damage parameter on overall analysis results, is included in an appendix. Analysis results are compared to the experimental results for each of the 32 CAI sandwich panel specimens tested to failure. The failure of each specimen is predicted using the high-fidelity, physicsbased analysis model developed here, and the results highlight key improvements in the understanding of honeycomb core sandwich panel CAI failure. Finally, a parametric study highlights the strength benefits compared to mass penalty for various core densities.

  19. Continuous Carbon Nanotube-Ultrathin Graphite Hybrid Foams for Increased Thermal Conductivity and Suppressed Subcooling in Composite Phase Change Materials.

    Science.gov (United States)

    Kholmanov, Iskandar; Kim, Jaehyun; Ou, Eric; Ruoff, Rodney S; Shi, Li

    2015-12-22

    Continuous ultrathin graphite foams (UGFs) have been actively researched recently to obtain composite materials with increased thermal conductivities. However, the large pore size of these graphitic foams has resulted in large thermal resistance values for heat conduction from inside the pore to the high thermal conductivity graphitic struts. Here, we demonstrate that the effective thermal conductivity of these UGF composites can be increased further by growing long CNT networks directly from the graphite struts of UGFs into the pore space. When erythritol, a phase change material for thermal energy storage, is used to fill the pores of UGF-CNT hybrids, the thermal conductivity of the UGF-CNT/erythritol composite was found to increase by as much as a factor of 1.8 compared to that of a UGF/erythritol composite, whereas breaking the UGF-CNT bonding in the hybrid composite resulted in a drop in the effective room-temperature thermal conductivity from about 4.1 ± 0.3 W m(-1) K(-1) to about 2.9 ± 0.2 W m(-1) K(-1) for the same UGF and CNT loadings of about 1.8 and 0.8 wt %, respectively. Moreover, we discovered that the hybrid structure strongly suppresses subcooling of erythritol due to the heterogeneous nucleation of erythritol at interfaces with the graphitic structures.

  20. Mechanical Property Analysis on Sandwich Structured Hybrid Composite Made from Natural Fibre, Glass Fibre and Ceramic Fibre Wool Reinforced with Epoxy Resin

    Science.gov (United States)

    Bharat, K. R.; Abhishek, S.; Palanikumar, K.

    2017-06-01

    Natural fibre composites find wide range of applications and usage in the automobile and manufacturing industries. They find lack in desired properties, which are required for present applications. In current scenario, many developments in composite materials involve the synthesis of Hybrid composite materials to overcome some of the lacking properties. In this present investigation, two sandwich structured hybrid composite materials have been made by reinforcing Aloe Vera-Ceramic Fibre Wool-Glass fibre with Epoxy resin matrix and Sisal fibre-Ceramic Fibre Wool-Glass fibre with Epoxy resin matrix and its mechanical properties such as Tensile, Flexural and Impact are tested and analyzed. The test results from the two samples are compared and the results show that sisal fibre reinforced hybrid composite has better mechanical properties than aloe vera reinforced hybrid composite.