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Sample records for hydroxyapatite reinforced polymers

  1. Hydroxyapatite-reinforced polymer biocomposites for synthetic bone substitutes

    Science.gov (United States)

    Roeder, Ryan K.; Converse, Gabriel L.; Kane, Robert J.; Yue, Weimin

    2008-03-01

    Hydroxyapatite (HA)-reinforced polymer biocomposites offer a robust system to engineer synthetic bone substitutes with tailored mechanical, biological, and surgical functions. The basic design rationale has been to reinforce a tough, biocompatible polymer matrix with a bioactive HA filler. A large number of studies have investigated modifications to the biocomposite structure and composition, aimed at improving the mechanical properties, often through modified or novel processing methods. In this article, the effects of the polymer composition and molecular orientation; the HA/polymer interface; and the HA-reinforcement content, morphology, preferred orientation, and size are reviewed with respect to mechanical properties, drawing frequent comparisons between various HA-reinforced polymer composites and bone tissue.

  2. Glass Fibre Reinforced Polymers

    NARCIS (Netherlands)

    Nikolaou, N.; Karagianni, L.; Sarakiniatti, M.V.

    2014-01-01

    This "designers' manual" is made during the TIDO-course AR0533 Innovation & Sustainability. Fibre reinforced polymers (FRPs) have been used in many applications over the years, from new construction to retrofitting. They are lightweight, no-corrosive, exhibit high specific strength and specific

  3. Mechanically-reinforced electrospun composite silk fibroin nanofibers containing hydroxyapatite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyunryung [School of Mechanical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Che, Lihua; Ha, Yoon [Department of Neurosurgery, College of Medicine, Yonsei University, Seoul 120-749 (Korea, Republic of); Ryu, WonHyoung, E-mail: whryu@yonsei.ac.kr [School of Mechanical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2014-07-01

    Electrospun silk fibroin (SF) scaffolds provide large surface area, high porosity, and interconnection for cell adhesion and proliferation and they may replace collagen for many tissue engineering applications. Despite such advantages, electrospun SF scaffolds are still limited as bone tissue replacement due to their low mechanical strengths. While enhancement of mechanical strengths by incorporating inorganic ceramics into polymers has been demonstrated, electrospinning of a mixture of SF and inorganic ceramics such as hydroxyapatite is challenging and less studied due to the aggregation of ceramic particles within SF. In this study, we aimed to enhance the mechanical properties of electrospun SF scaffolds by uniformly dispersing hydroxyapatite (HAp) nanoparticles within SF nanofibers. HAp nanoaprticles were modified by γ-glycidoxypropyltrimethoxysilane (GPTMS) for uniform dispersion and enhanced interfacial bonding between HAp and SF fibers. Optimal conditions for electrospinning of SF and GPTMS-modified HAp nanoparticles were identified to achieve beadless nanofibers without any aggregation of HAp nanoparticles. The MTT and SEM analysis of the osteoblasts-cultured scaffolds confirmed the biocompatibility of the composite scaffolds. The mechanical properties of the composite scaffolds were analyzed by tensile tests for the scaffolds with varying contents of HAp within SF fibers. The mechanical testing showed the peak strengths at the HAp content of 20 wt.%. The increase of HAp content up to 20 wt.% increased the mechanical properties of the composite scaffolds, while further increase above 20 wt.% disrupted the polymer chain networks within SF nanofibers and weakened the mechanical strengths. - Highlights: • Electrospun composite silk fibroin scaffolds were mechanically-reinforced. • GPTMS enhanced hydroxyapatite distribution in silk fibroin nanofibers. • Mechanical property of composite scaffolds increased up to 20% of hydroxyapatite. • Composite

  4. Sensored fiber reinforced polymer grate

    Science.gov (United States)

    Ross, Michael P.; Mack, Thomas Kimball

    2017-08-01

    Various technologies described herein pertain to a sensored grate that can be utilized for various security fencing applications. The sensored grate includes a grate framework and an embedded optical fiber. The grate framework is formed of a molded polymer such as, for instance, molded fiber reinforced polymer. Further, the grate framework includes a set of elongated elements, where the elongated elements are spaced to define apertures through the grate framework. The optical fiber is embedded in the elongated elements of the grate framework. Moreover, bending or breaking of one or more of the elongated elements can be detected based on a change in a characteristic of input light provided to the optical fiber compared to output light received from the optical fiber.

  5. Mechanical characterization of fiber reinforced Polymer Concrete

    Directory of Open Access Journals (Sweden)

    João Marciano Laredo dos Reis

    2005-09-01

    Full Text Available A comparative study between epoxy Polymer Concrete plain, reinforced with carbon and glass fibers and commercial concrete mixes was made. The fibers are 6 mm long and the fiber content was 2% and 1%, respectively, in mass. Compressive tests were performed at room temperature and load vs. displacement curves were plotted up to failure. The carbon and glass fibers reinforcement were randomly dispersed into the matrix of polymer concrete. An increase in compressive properties was observed as function of reinforcement. The comparison also showed that Polymer Concrete, plain and reinforced, has a better performance than regular market concrete, suggesting that PC is a reliable alternative for construction industry.

  6. Novel porous graphene oxide and hydroxyapatite nanosheets-reinforced sodium alginate hybrid nanocomposites for medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Guangyao [School of Mechanical and Electrical Engineering, East China Jiaotong University, Nanchang 330013 (China); Luo, Honglin [Research Institute of Biomaterials and Transportation, East China Jiaotong University, Nanchang 330013 (China); School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin 300072 (China); Zuo, Guifu [Hebei Provincial Key Laboratory of Inorganic Nonmetallic Materials, College of Materials Science and Engineering, Hebei United University, Tangshan 063009 (China); Ren, Kaijing [Department of Joint Surgery, Tianjin Hospital, Tianjin 300211 (China); Wan, Yizao, E-mail: yzwantju@126.com [Research Institute of Biomaterials and Transportation, East China Jiaotong University, Nanchang 330013 (China); School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin 300072 (China)

    2015-09-15

    Graphene oxide (GO) and hydroxyapatite (HAp) are frequently used as reinforcements in polymers to improve mechanical and biological properties. In this work, novel porous hybrid nanocomposites consisting of GO, HAp, and sodium alginate (SA) have been prepared by facile solution mixing and freeze drying in an attempt to obtain a scaffold with desirable mechanical and biological properties. The as-prepared porous GO/HAp/SA hybrid nanocomposites were characterized by SEM, XRD, FTIR, TGA, and mechanical testing. In addition, preliminary cell behavior was assessed by CCK8 assay. It is found that the GO/HAp/SA nanocomposites show improved compressive strength and modulus over neat SA and HAp/SA nanocomposites. CCK8 results reveal that the GO/HAp/SA nanocomposites show enhanced cell proliferation over neat SA and GO/SA nanocomposite. It has been demonstrated that GO/HAp20/SA holds promise in bone tissue engineering. - Graphical abstract: Display Omitted - Highlights: • Graphene oxide (GO), hydroxyapatite (HAp), and alginate (SA) nanocomposites were fabricated. • The novel porous composites were prepared by solution mixture and freeze drying. • The GO/HAp/SA had porous structure with porosity > 85% and pore size > 150 μm. • The GO/HAp/SA exhibited improved mechanical properties over HAp/SA counterparts. • The GO/HAp/SA showed enhanced cell proliferation over GO/SA counterparts.

  7. Mechanical characterization of fiber reinforced Polymer Concrete

    OpenAIRE

    Reis,João Marciano Laredo dos

    2005-01-01

    A comparative study between epoxy Polymer Concrete plain, reinforced with carbon and glass fibers and commercial concrete mixes was made. The fibers are 6 mm long and the fiber content was 2% and 1%, respectively, in mass. Compressive tests were performed at room temperature and load vs. displacement curves were plotted up to failure. The carbon and glass fibers reinforcement were randomly dispersed into the matrix of polymer concrete. An increase in compressive properties was observed as fun...

  8. Glass Fiber Reinforced Polymer Dowel Bar Evaluation

    Science.gov (United States)

    2012-09-01

    Glass Fiber Reinforced Polymer (GFRP) dowel bars were installed on one new construction project and two dowel bar : retrofit projects to evaluate the performance of this type of dowel bar in comparison to steel dowel bars installed on the same : cont...

  9. Health monitoring of precast bridge deck panels reinforced with glass fiber reinforced polymer (GFRP) bars.

    Science.gov (United States)

    2012-03-01

    The present research project investigates monitoring concrete precast panels for bridge decks that are reinforced with Glass Fiber Reinforced Polymer (GFRP) bars. Due to the lack of long term research on concrete members reinforced with GFRP bars, lo...

  10. Nano polypeptide particles reinforced polymer composite fibers.

    Science.gov (United States)

    Li, Jiashen; Li, Yi; Zhang, Jing; Li, Gang; Liu, Xuan; Li, Zhi; Liu, Xuqing; Han, Yanxia; Zhao, Zheng

    2015-02-25

    Because of the intensified competition of land resources for growing food and natural textile fibers, there is an urgent need to reuse and recycle the consumed/wasted natural fibers as regenerated green materials. Although polypeptide was extracted from wool by alkaline hydrolysis, the size of the polypeptide fragments could be reduced to nanoscale. The wool polypeptide particles were fragile and could be crushed down to nano size again and dispersed evenly among polymer matrix under melt extrusion condition. The nano polypeptide particles could reinforce antiultraviolet capability, moisture regain, and mechanical properties of the polymer-polypeptide composite fibers.

  11. Fiber reinforced polymer composites for bridge structures

    Directory of Open Access Journals (Sweden)

    Alexandra CANTORIU

    2013-12-01

    Full Text Available Rapid advances in construction materials technology have led to the emergence of new materials with special properties, aiming at safety, economy and functionality of bridges structures. A class of structural materials which was originally developed many years ago, but recently caught the attention of engineers involved in the construction of bridges is fiber reinforced polymer composites. This paper provides an overview of fiber reinforced polymer composites used in bridge structures including types, properties, applications and future trends. The results of this study have revealed that this class of materials presents outstanding properties such as high specific strength, high fatigue and environmental resistance, lightweight, stiffness, magnetic transparency, highly cost-effective, and quick assembly, but in the same time high initial costs, lack of data on long-term field performance, low fire resistance. Fiber reinforced polymer composites were widely used in construction of different bridge structures such as: deck and tower, I-beams, tendons, cable stands and proved to be materials for future in this field.

  12. In vitro studies of graphene oxide reinforced hydroxyapatite nanobiocomposite on human erythrocytes

    Science.gov (United States)

    Radha, G.; Rohith Vinod, K.; Venkatesan, Balaji; Vellaichamy, Elangovan; Balakumar, S.

    2017-05-01

    We report the interaction of graphene oxide reinforced hydroxyapatite (GO-HAp) nanocomposites with human erythrocytes. The hemocompatibility of GO-HAp found to be superior as compared to the pristine graphene oxide. It is found that the HAp nanoparticles on GO decrease the disruption of erythrocytes by minimizing the exposure of oxygen groups to phosphatidylcholine surface of erythrocyte membrane and it enhances hemocompatibility. Further, it is also found that the graphene oxide reinforced HAp nanobiocomposite enhances the metabolic activity of osteoblasts-like cells by promoting cell proliferation.

  13. Self-Healing in Nanoparticle-Reinforced Polymers and other Polymer Systems

    NARCIS (Netherlands)

    Picken, S.J.; Mookhoek, S.D.; Fischer, H.R.; Zwaag, S. van der

    2010-01-01

    This chapter aims at combining new insights in the field of (liquid encapsulated) self healing polymer systems as well as nanoparticle reinforced polymers to set the direction for the development of nanoparticle reinforced self healing polymers. In the case of self healing polymers the strategy is

  14. Retrofit of existing reinforced concrete bridges with fiber reinforced polymer composites

    Science.gov (United States)

    2001-12-01

    A two-part research was focused on examining various issues related to the use of fiber reinforced polymer (FRP) composites for strengthening of existing reinforced concrete bridges. A summary of each phase is presented separately.

  15. Invitro Evaluation of Fluoride Release from Hydroxyapatite Reinforced Glass Ionomer with or without Protective Coating.

    Science.gov (United States)

    Tiwari, Shilpi; Nandlal, Bhojraj

    2016-04-01

    Glass Ionomer Cement (GIC) is well known for its fluoride releasing property but has its own drawbacks of poor mechanical properties, sensitivity to initial desiccation and moisture contamination. To overcome these, search led to the reinforcement of hydroxyapatite and application of surface coating agent but their effect on fluoride release is still not clear. To evaluate and compare the release of fluoride from Hydroxyapatite Reinforced Glass Ionomer (HA-GIC) with and without protective coating. Specimens were prepared as follows- Eight percent by weight conventional glass ionomer was replaced by hydroxyapatite powder (HA) and an indigenous product was prepared (HA-GIC). This powder was mixed with liquid of conventional GIC and allowed to set, then G coat plus coating agent was applied in surface coated group and light cured. Fluoride release of the sample was measured every 24 hrs for seven days and weekly from 7(th) to 21(st) day using combination ion selective electrode. Mean values clearly reveal a significant decrease in the fluoride release from day 1 to day 21 for both the groups. Results of repeated measure ANOVA revealed statistically significant difference between two groups (p glass ionomer will allow for slow and steady release of fluoride for a long period of time into oral environment.

  16. Investigation of nanoscale reinforcement into textile polymers

    Science.gov (United States)

    Khan, Mujibur Rahman

    A dual inclusion strategy for textile polymers has been investigated to increase elastic energy storage capacity of fibers used in high velocity impact applications. Commercial fibers such as Spectra and Dyneema are made from ultra high molecular weight polyethylene (UHMWPE). Dynamic elastic energy of these fibers is still low therefore limiting their wholesale application without a secondary metallic or ceramic component. The idea in this investigation is to develop methodologies so that the elastic energy of polyethylene based fibers can be increased by several folds. This would allow manufacturing of an all-fabric system for high impact applications. The dual inclusion consists of a polymer phase and a nanoscale inorganic phase to polyethylene. The polymer phase was nylon-6 and the inorganic phase was carbon nanotubes (CNTs). Nylon-6 was blended as a minor phase into UHMWPE and was chosen because of its large fracture strain -- almost one order higher than that of UHMWPE. On the other hand, CNTs with their very high strength, modulus, and aspect ratio, contributed to sharing of load and sliding of polymer interfaces as they aligned during extrusion and strain hardening processes. A solution spinning process was developed to produce UHMWPE filaments reinforced with CNTs and nylon-6. The procedure involved dispersing of CNTs into paraffin oil through sonication followed by dissolving polymers into paraffin-CNT solution using a homogenizer. The admixture was fed into a single screw extruder for melt mixing and extrusion through an orifice. The extrudate was rinsed via a hexane bath, stabilized through a heater, and then drawn into a filament winder with controlled stretching. In the next step, the as produced filaments were strain-hardened through repeated loading unloading cycles under tension. Neat and reinforced filaments were characterized through DSC (Differential Scanning Calorimetry), XRD (X-ray Diffraction), Raman Spectroscopy, SEM (Scanning Electron

  17. Nanoscale Reinforced, Polymer Derived Ceramic Matrix Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Rajendra Bordia

    2009-07-31

    The goal of this project was to explore and develop a novel class of nanoscale reinforced ceramic coatings for high temperature (600-1000 C) corrosion protection of metallic components in a coal-fired environment. It was focused on developing coatings that are easy to process and low cost. The approach was to use high-yield preceramic polymers loaded with nano-size fillers. The complex interplay of the particles in the polymer, their role in controlling shrinkage and phase evolution during thermal treatment, resulting densification and microstructural evolution, mechanical properties and effectiveness as corrosion protection coatings were investigated. Fe-and Ni-based alloys currently used in coal-fired environments do not possess the requisite corrosion and oxidation resistance for next generation of advanced power systems. One example of this is the power plants that use ultra supercritical steam as the working fluid. The increase in thermal efficiency of the plant and decrease in pollutant emissions are only possible by changing the properties of steam from supercritical to ultra supercritical. However, the conditions, 650 C and 34.5 MPa, are too severe and result in higher rate of corrosion due to higher metal temperatures. Coating the metallic components with ceramics that are resistant to corrosion, oxidation and erosion, is an economical and immediate solution to this problem. Good high temperature corrosion protection ceramic coatings for metallic structures must have a set of properties that are difficult to achieve using established processing techniques. The required properties include ease of coating complex shapes, low processing temperatures, thermal expansion match with metallic structures and good mechanical and chemical properties. Nanoscale reinforced composite coatings in which the matrix is derived from preceramic polymers have the potential to meet these requirements. The research was focused on developing suitable material systems and

  18. In vitro biocompatibility of hydroxyapatite-reinforced polymeric composites manufactured by selective laser sintering.

    Science.gov (United States)

    Zhang, Y; Hao, L; Savalani, M M; Harris, R A; Di Silvio, L; Tanner, K E

    2009-12-15

    The selective laser sintering (SLS) technique was used to manufacture hydroxyapatite-reinforced polyethylene and polyamide composites as potential customized maxillofacial implants. In vitro tests were carried out to assess cellular responses, in terms of cell attachment, morphology, proliferation, differentiation, and mineralized nodule formation, using primary human osteoblast cells. This study showed that the SLS composite processed was biocompatible, with no adverse effects observed on cell viability and metabolic activity, supporting a normal metabolism and growth pattern for osteoblasts. Positive von Kossa staining demonstrated the presence of bone-like mineral on the SLS materials. Higher hydroxyapatite content composites enhanced cell proliferation, increased alkaline phosphatase activity, and produced more osteocalcin. The present findings showed that SLS materials have good in vitro biocompatibility and hence demonstrated biologically the potential of SLS for medical applications.

  19. Seismic Behavior of Substandard RC Columns Retrofitted with Embedded Aramid Fiber Reinforced Polymer (AFRP Reinforcement

    Directory of Open Access Journals (Sweden)

    Engin C. Seyhan

    2015-12-01

    Full Text Available Many existing reinforced concrete structures were constructed with substandard characteristics. Low quality concrete, poor transverse reinforcement details and insufficient flexural strength are among the most common deficiencies. While substandard structures are in need of retrofitting, particularly in seismic areas, problems such as high costs and disturbance to occupants are major obstacles for retrofit interventions. Fiber reinforced polymers can provide feasible retrofit solutions with minimum disturbance to occupants. In this study, the basic aim is to investigate the flexural seismic performance of substandard reinforced concrete columns retrofitted with embedded longitudinal fiber reinforced polymer reinforcement without increasing the original dimensions of the columns. In the experimental study, the reference and retrofitted columns were tested under constant vertical and reversed cyclic lateral loads. Three different connection methods of aramid fiber reinforced polymer reinforcement to the footing were investigated experimentally. A significant enhancement was obtained in lateral flexural strength through the proposed retrofitting method. Furthermore, it was observed that the cyclic lateral drift capacities of the retrofitted columns were as high as 3%, which can be deemed as quite satisfactory against seismic actions. The comparison of the experimental data with analytical calculations revealed that a conventional design approach assuming composite action between concrete and fiber reinforced polymer reinforcement can be used for flexural retrofit design. Experimental results also demonstrated that strain limit for longitudinal fiber reinforced polymer (FRP reinforcement should be remarkably lower in case of reversed cyclic loading conditions.

  20. Hydroxyapatite and bioactive glass surfaces for fiber reinforced composite implants via surface ablation by Excimer laser.

    Science.gov (United States)

    Kulkova, Julia; Moritz, Niko; Huhtinen, Hannu; Mattila, Riina; Donati, Ivan; Marsich, Eleonora; Paoletti, Sergio; Vallittu, Pekka K

    2017-11-01

    In skeletal reconstructions, composites, such as bisphenol-A-glycidyldimethacrylate resin reinforced with glass fibers, are potentially useful alternatives to metallic implants. Recently, we reported a novel method to prepare bioactive surfaces for these composites. Surface etching by Excimer laser was used to expose bioactive glass granules embedded in the resin. The purpose of this study was to analyze two types of bioactive surfaces created by this technique. The surfaces contained bioactive glass and hydroxyapatite granules. The selected processing parameters were adequate for the creation of the surfaces. However, the use of porous hydroxyapatite prevented the complete exposure the granules. In cell culture, for bioactive glass coatings, the pattern of proliferation of MG63 cells was comparable to that in the positive control group (Ti6Al4V) while inferior cell proliferation was observed on the surfaces containing hydroxyapatite granules. Scanning electron microscopy revealed osteointegration of implants with both types of surfaces. The technique is suitable for the exposure of solid bioactive glass granules. However, the long-term performance of the surfaces needs further assessment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Hydroxyapatite Whisker Reinforced 63s Glass Scaffolds for Bone Tissue Engineering

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    Cijun Shuai

    2015-01-01

    Full Text Available Bioactive glass (BG is widely used for bone tissue engineering. However, poor mechanical properties are the major shortcomings. In the study, hydroxyapatite nanowhisker (HANw was used as a reinforcement to improve the mechanical properties. 63s glass/HANw scaffolds were successfully fabricated by selective laser sintering (SLS. It was found that the optimal compressive strength and fracture toughness were achieved when 10 wt.% HANw was added. This led to 36% increase in compressive strength and 83% increase in fracture toughness, respectively, compared with pure 63s glass scaffolds. Different reinforcement mechanisms were analyzed based on the microstructure investigation. Whisker bridging and whisker pulling-out were efficient in absorbing crack propagating energy, resulting in the improvement of the mechanical properties. Moreover, bioactivity and biocompatibility of the scaffolds were evaluated in vitro. The results showed that composite scaffolds with 10 wt.% HANw exhibited good apatite-forming ability and cellular affinity.

  2. Hydrophobicity, surface tension, and zeta potential measurements of glass-reinforced hydroxyapatite composites.

    Science.gov (United States)

    Lopes, M A; Monteiro, F J; Santos, J D; Serro, A P; Saramago, B

    1999-06-15

    Wettability and zeta potential studies were performed to characterize the hydrophobicity, surface tension, and surface charge of P2O5-glass-reinforced hydroxyapatite composites. Quantitative phase analysis was performed by the Rietveld method using GSAS software applied to X-ray diffractograms. Surface charge was assessed by zeta potential measurements. Protein adsorption studies were performed using vitronectin. Contact angles and surface tensions variation with time were determined by the sessile and pendent drop techniques, respectively, using ADSA-P software. The highest (-18.1 mV) and lowest (-28.7 mV) values of zeta potential were found for hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP), respectively, with composite materials presenting values in between. All studied bioceramic materials showed similar solid surface tension. For HA and beta-TCP, solid surface tensions of 46.7 and 45.3 mJ/m2, respectively, were obtained, while composites presented intermediate surface tension values. The dispersive component of surface tension was the predominant one for all materials studied. Adhesion work values between the vitronectin solution and HA and beta-TCP were found to be 79.8 and 88.0 mJ/m2, respectively, while the 4.0 wt % glass composites showed slightly lower values than the 2.5 wt % ones. The presence of beta-TCP influenced surface charge, hydrophobicity, and protein adsorption of the glass-reinforced HA composites, and therefore indirectly affected cell-biomaterial interactions.

  3. Hydroxyapatite reinforced inherent RGD containing silk fibroin composite scaffolds: Promising platform for bone tissue engineering.

    Science.gov (United States)

    Behera, Sibaram; Naskar, Deboki; Sapru, Sunaina; Bhattacharjee, Promita; Dey, Tuli; Ghosh, Ananta K; Mandal, Mahitosh; Kundu, Subhas C

    2017-07-01

    Replacement and repair of ectopic bone defects and traumatized bone tissues are done using porous scaffolds and composites. The prerequisites for such scaffolds include high mechanical strength, osseoconductivity and cytocompatibility. The present work is designed to address such requirements by fabricating a reinforced cytocompatible scaffold. Biocompatible silk protein fibroin collected from tropical non-mulberry tasar silkworm (Antheraea mylitta) is used to fabricate fibroin-hydroxyapatite (HAp) nanocomposite particles using chemical precipitation method. In situ reinforcement of fibroin-HAp nanocomposite and external deposition of HAp particles on fibroin scaffold is carried out for comparative evaluations of bio-physical and biochemical characteristics. HAp deposited fibroin scaffolds provide greater mechanical strength and cytocompatibility, when compared with fibroin-HAp nanoparticles reinforced fibroin scaffolds. Minimal immune responses of both types of composite scaffolds are observed using osteoblast-macrophage co-culture model. Nanocomposite reinforced fibroin scaffold can be tailored further to accommodate different requirements depending on bone type or bone regeneration period. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Development and performance evaluation of fiber reinforced polymer bridge.

    Science.gov (United States)

    2014-03-01

    Fiber reinforced polymers (FRP) have become more popular construction materials in the last decade due to the reduction of : material costs. The installation and performance evaluation of the first FRP-wrapped balsa wood bridge in Louisiana is descri...

  5. Investigation of digital light processing using fibre-reinforced polymers

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; Pedersen, David Bue; Nielsen, Jakob Skov

    2016-01-01

    Literature research shows multiple applications of fibre-reinforced polymers (FRP) respectively in fused deposition modelling and gypsum printing influencing the quality of the products in terms of stress and strain resistance as well as flexibility. So far, applications of fibre......-reinforced polymers in digital light processing (DLP) are limited. Fibre-reinforced polymer composites were manufactured into test objects using digital light processing. Short fibres were used in an unordered manner. An anisotropic property due to fibre orientation within the material was observed. The importance...... of fibre length and shape compared to layer thickness has been investigated including concepts to circumvent clustering of the fibres.This research contributes to the implementation of fibre-reinforced polymers in additive manufacturing technologies. Digital light processing allows generation...

  6. Axial Compression Tests on Corroded Reinforced Concrete Columns Consolidated with Fibre Reinforced Polymers

    Directory of Open Access Journals (Sweden)

    Bin Ding

    2017-06-01

    Full Text Available Reinforced concrete structure featured by strong bearing capacity, high rigidity, good integrity, good fire resistance, and extensive applicability occupies a mainstream position in contemporary architecture. However, with the development of social economy, people need higher requirements on architectural structure; durability, especially, has been extensively researched. Because of the higher requirement on building material, ordinary reinforced concrete structure has not been able to satisfy the demand. As a result, some new materials and structures have emerged, for example, fibre reinforced polymers. Compared to steel reinforcement, fibre reinforced polymers have many advantages, such as high tensile strength, good durability, good shock absorption, low weight, and simple construction. The application of fibre reinforced polymers in architectural structure can effectively improve the durability of the concrete structure and lower the maintenance, reinforcement, and construction costs in severe environments. Based on the concepts of steel tube concrete, fibre reinforced composite material confined concrete, and fibre reinforced composite material tubed concrete, this study proposes a novel composite structure, i.e., fibre reinforced composite material and steel tube concrete composite structure. The structure was developed by pasting fibre around steel tube concrete and restraining core concrete using fibre reinforced composite material and steel tubes. The bearing capacity and ultimate deformation capacity of the structure was tested using column axial compression test.

  7. Structural Behavior of Concrete Beams Reinforced with Basalt Fiber Reinforced Polymer (BFRP) Bars

    Science.gov (United States)

    Ovitigala, Thilan

    The main challenge for civil engineers is to provide sustainable, environmentally friendly and financially feasible structures to the society. Finding new materials such as fiber reinforced polymer (FRP) material that can fulfill the above requirements is a must. FRP material was expensive and it was limited to niche markets such as space shuttles and air industry in the 1960s. Over the time, it became cheaper and spread to other industries such as sporting goods in the 1980-1990, and then towards the infrastructure industry. Design and construction guidelines are available for carbon fiber reinforced polymer (CFRP), aramid fiber reinforced polymer (AFRP) and glass fiber reinforced polymer (GFRP) and they are currently used in structural applications. Since FRP is linear elastic brittle material, design guidelines for the steel reinforcement are not valid for FRP materials. Corrosion of steel reinforcement affects the durability of the concrete structures. FRP reinforcement is identified as an alternative to steel reinforcement in corrosive environments. Although basalt fiber reinforced polymer (BFRP) has many advantages over other FRP materials, but limited studies have been done. These studies didn't include larger BFRP bar diameters that are mostly used in practice. Therefore, larger beam sizes with larger BFRP reinforcement bar diameters are needed to investigate the flexural and shear behavior of BFRP reinforced concrete beams. Also, shear behavior of BFRP reinforced concrete beams was not yet studied. Experimental testing of mechanical properties and bond strength of BFRP bars and flexural and shear behavior of BFRP reinforced concrete beams are needed to include BFRP reinforcement bars in the design codes. This study mainly focuses on the use of BFRP bars as internal reinforcement. The test results of the mechanical properties of BFRP reinforcement bars, the bond strength of BFRP reinforcement bars, and the flexural and shear behavior of concrete beams

  8. Performance of a bridge deck with glass fiber reinforced polymer bars as the top mat of reinforcement.

    Science.gov (United States)

    2005-01-01

    The purpose of this research was to investigate the performance of glass fiber reinforced polymer (GFRP) bars as reinforcement for concrete decks. Today's rapid bridge deck deterioration is calling for a replacement for steel reinforcement. The advan...

  9. optimisation of thickness of fibre reinforced polymer sheets

    African Journals Online (AJOL)

    user

    2017-01-01

    Jan 1, 2017 ... The use of Fiber Reinforced Polymer (FRP) is becoming a widely accepted solution for repairing and strengthening of deteriorated reinforced concrete members, to restore their load carrying capacities. One of the major concerns in the use of FRP is its cost. This therefore calls for the use of efficient and cost ...

  10. Synthesis and Characterization of Collagen Scaffolds Reinforced by Eggshell Derived Hydroxyapatite for Tissue Engineering.

    Science.gov (United States)

    Padmanabhan, Sanosh Kunjalukkal; Salvatore, Luca; Gervaso, Francesca; Catalano, Massimo; Taurino, Antonietta; Sannino, Alessando; Licciulli, Antonio

    2015-01-01

    In this work, we synthesized porous nanohydroxyapatite/collagen composite scaffold (nHA-COL), which resemble extracellular matrices in bone and cartilage tissues. Nano hydroxyapatite (nHA) was successfully nucleated in to the collagen matrix using hen eggshell as calcium biogenic source. Porosity was evaluated by apparent and theoretical density measurement. Porosity of all scaffolds was in the range of 95-98%. XRD and TEM analyses show the purity and size of nucleated HA around 10 nm and selected area electron diffraction (SAED) analysis reveals the polycrystalline nature of nucleated HA. SEM analysis reveals (i) all the scaffolds have interconnected pores with an average pore diameter of 130 micron and (ii) aggregates of hydroxyapatite were strongly embedded in the collagen matrix for both composite scaffolds compared with pure collagen scaffold. EDS analysis shows the Ca/P stoichiometric ratio around 1.67 and FTIR reveals the chemical interaction between the collagen molecule and HA particles. The testing of mechanical properties evidenced that incorporation of HA resulted in up to a two-fold increase in compressive modulus with high reinforcement level (-7 kPa for 50HA-50COL) compared to pure collagen scaffold.

  11. Density and Morphological Properties of Some Reinforced Polymers ...

    African Journals Online (AJOL)

    acer

    Density and Morphological Properties of Some Reinforced Polymers. 1. P.A.P. Mamza* and. 2. B.T. Nwufo. 1.Department of Chemistry ... crystallized polymers are based on two phase systems (crystalline and amorphous) and each .... applications in the industries. REFERENCES. Tager, A. (1978). Physical Chemistry of.

  12. Flows in polymers, reinforced polymers and composites a multi-scale approach

    CERN Document Server

    Binetruy, Christophe; Keunings, Roland

    2015-01-01

    This book gives a detailed and practical introduction to complex flows of polymers and reinforced polymers as well as the flow of simple fluids in complex microstructures. Over the last decades, an increasing number of functional and structural parts, made so far with metals, has been progressively reengineered by replacing metallic materials by polymers, reinforced polymers and composites. The motivation for this substitution may be the weight reduction, the simpler, cheaper or faster forming process, or the ability to exploit additional functionalities. The present Brief surveys modern developments related to the multi-scale modeling and simulation of polymers, reinforced polymers, that involve a flowing microstructure and continuous fiber-reinforced composites, wherein the fluid flows inside a nearly stationary multi-scale microstructure. These developments concern both multi-scale modeling, defining bridges between the micro and macro scales - with special emphasis on the mesoscopic scale at which kinetic...

  13. Saccaharum Cilliare Fiber Reinforced Polymer Composites

    Directory of Open Access Journals (Sweden)

    A. S. Singha

    2008-01-01

    Full Text Available Renewable resources such as natural fibers in the field of fiber reinforced materials with their new range of applications represent an important basis in order to fulfill the ecological objective of creating eco-friendly materials. In views of enormous advantages a study on green composites using Saccaharum cilliare fiber as a reinforcing material and urea-formaldehyde (UF as a novel matrix has been made. First of all urea-formaldehyde resin synthesized was reinforced withSaccaharum cilliare fiber. Reinforcement of the fiber was accomplished in three different forms particle (200 micron reinforcement, short fiber (3 mm. reinforcement and long fiber (6 mm reinforcement. Present work reveals that mechanical properties such as: tensile strength, compressive strength and wear resistance of urea -formaldehyde resin (UF increases to a significant extent when reinforced with Saccaharum cilliare fiber which is found in outsized amount in the Himalayan Region. These mechanical properties mainly depend upon the dimensions of the fiber used. Analysis of results shows that particle reinforcement is more effective as compared to short and long fiber reinforcement. Morphological and thermal studies of these composites have also been carried out.

  14. A REVIEW ON SISAL FIBER REINFORCED POLYMER COMPOSITES

    Directory of Open Access Journals (Sweden)

    Kuruvilla Joseph

    1999-12-01

    Full Text Available ABSTRACT The global demand for wood as a building material is steadily growing, while the availability of this natural resource is diminishing. This situation has led to the development of alternative materials. Of the various synthetic materials that have been explored and advocated, polymer composites claim a major participation as building materials. There has been a growing interest in utilizing natural fibres as reinforcement in polymer composite for making low cost construction materials in recent years. Natural fibres are prospective reinforcing materials and their use until now has been more traditional than technical. They have long served many useful purposes but the application of the material technology for the utilization of natural fibres as reinforcement in polymer matrix took place in comparatively recent years. Economic and other related factors in many developing countries where natural fibres are abundant, demand that scientists and engineers apply appropriate technology to utilize these natural fibres as effectively and economically as possible to produce good quality fibre reinforced polymer composites for housing and other needs. Among the various natural fibres, sisal is of particular interest in that its composites have high impact strength besides having moderate tensile and flexural properties compared to other lignocellulosic fibres. The present paper surveys the research work published in the field of sisal fibre reinforced polymer composites with special reference to the structure and properties of sisal fibre, processing techniques, and the physical and mechanical properties of the composites.

  15. Control of the pore architecture in three-dimensional hydroxyapatite-reinforced hydrogel scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Roman, Jesus; Cabanas, MarIa Victoria; Pena, Juan; Vallet-RegI, MarIa, E-mail: vallet@farm.ucm.es [Departamento de Quimica Inorganica y Bioinorganica, Facultad de Farmacia, Universidad Complutense, 28040-Madrid (Spain)

    2011-08-15

    Hydrogels (gellan or agarose) reinforced with nanocrystalline carbonated hydroxyapatite (nCHA) were prepared by the GELPOR3D technique. This simple method is characterized by compositional flexibility; it does not require expensive equipment, thermal treatment, or aggressive or toxic solvents, and yields a three-dimensional (3D) network of interconnected pores 300-900 {mu}m in size. In addition, an interconnected porosity is generated, yielding a hierarchical porous architecture from the macro to the molecular scale. This porosity depends on both the drying/preservation technology (freeze drying or oven drying at 37 deg. C) and on the content and microstructure of the reinforcing ceramic. For freeze-dried samples, the porosities were approximately 30, 66 and below 3% for pore sizes of 600-900 {mu}m, 100-200 {mu}m and 50-100 nm, respectively. The pore structure depends much on the ceramic content, so that higher contents lead to the disappearance of the characteristic honeycomb structure observed in low-ceramic scaffolds and to a lower fraction of the 100-200-{mu}m-sized pores. The nature of the hydrogel did not affect the pore size distribution but was crucial for the behavior of the scaffolds in a hydrated medium: gellan-containing scaffolds showed a higher swelling degree owing to the presence of more hydrophilic groups.

  16. Experimental analysis of reinforced concrete beams strengthened in bending with carbon fiber reinforced polymer

    Directory of Open Access Journals (Sweden)

    M. M. VIEIRA

    Full Text Available The use of carbon fiber reinforced polymer (CFRP has been widely used for the reinforcement of concrete structures due to its practicality and versatility in application, low weight, high tensile strength and corrosion resistance. Some construction companies use CFRP in flexural strengthening of reinforced concrete beams, but without anchor systems. Therefore, the aim of this study is analyze, through an experimental program, the structural behavior of reinforced concrete beams flexural strengthened by CFRP without anchor fibers, varying steel reinforcement and the amount of carbon fibers reinforcement layers. Thus, two groups of reinforced concrete beams were produced with the same geometric feature but with different steel reinforcement. Each group had five beams: one that is not reinforced with CFRP (reference and other reinforced with two, three, four and five layers of carbon fibers. Beams were designed using a computational routine developed in MAPLE software and subsequently tested in 4-point points flexural test up to collapse. Experimental tests have confirmed the effectiveness of the reinforcement, ratifying that beams collapse at higher loads and lower deformation as the amount of fibers in the reinforcing layers increased. However, the increase in the number of layers did not provide a significant increase in the performance of strengthened beams, indicating that it was not possible to take full advantage of strengthening applied due to the occurrence of premature failure mode in the strengthened beams for pullout of the cover that could have been avoided through the use of a suitable anchoring system for CFRP.

  17. Properties of Fiber Reinforced Polymer Concrete

    Directory of Open Access Journals (Sweden)

    Marinela Bărbuţă

    2008-01-01

    Full Text Available Polymer concrete is a composite material realized with resin and aggregates. In the present study the epoxy resin was used for binding the aggregates. In the composition were introduced near the fly ash, used as filler, the cellulose fibers. The mechanical characteristics such as compressive strength, flexural strength and split tensile strength of polymer concrete with fibers were investigated. The fiber percentage was constant, the epoxy resin and the filler dosages were varied. The cellulose fiber had not improved the mechanical characteristics of the polymer concrete in comparison to that of polymer concrete without cellulose fibers.

  18. FATIGUE PROPERTIES OF SPRING REINFORCES POLYMER GEARS

    Directory of Open Access Journals (Sweden)

    Hilal CAN

    2005-03-01

    Full Text Available Failure of gears, occur surface pressure stress and fracture at base of teeth. For steel gears, it is known that process of carburizing increases fatigue strength. Internal stress on the surface increases of fracture fatigue strength. In this study fatigue properties of polypropylene gear reinforced with 1.2 mm wire diameter metallic springs was investigated. Extension springs were used as reinforcement element and placed into the mould and stretched before injection of polypropylene material into the mould. After injection of polypropylene, stretched springs were loosened in order to obtain pre-stressing. Fatigue tests were performed on the produced gear. Reinforcement increased the strength of gears. At result of experiments, pre-stressing increase in service life 12 times more than that of specimens without reinforcement.

  19. Entanglement network in nanoparticle reinforced polymers.

    Science.gov (United States)

    Riggleman, Robert A; Toepperwein, Gregory; Papakonstantopoulos, George J; Barrat, Jean-Louis; de Pablo, Juan J

    2009-06-28

    Polymer nanocomposites have been widely studied in efforts to engineer materials with mechanical properties superior to those of the pure polymer, but the molecular origins of the sought-after improved properties have remained elusive. An ideal polymer nanocomposite model has been conceived in which the nanoparticles are dispersed throughout the polymeric matrix. A detailed examination of topological constraints (or entanglements) in a nanocomposite glass provides new insights into the molecular origin of the improved properties in polymer nanocomposites by revealing that the nanoparticles impart significant enhancements to the entanglement network. Nanoparticles are found to serve as entanglement attractors, particularly at large deformations, altering the topological constraint network that arises in the composite material.

  20. Properties of Fiber Reinforced Polymer Concrete

    National Research Council Canada - National Science Library

    Marinela Bărbuţă; Maria Harja

    2008-01-01

    .... In the composition were introduced near the fly ash, used as filler, the cellulose fibers. The mechanical characteristics such as compressive strength, flexural strength and split tensile strength of polymer concrete with fibers were investigated...

  1. Porous polymer/hydroxyapatite scaffolds: characterization and biocompatibility investigations.

    NARCIS (Netherlands)

    Douglas, T.E.L.; Pamula, E.; Hauk, D.; Wiltfang, J.; Sivananthan, S.; Sherry, E.; Warnke, P.H.

    2009-01-01

    Poly-lactic-glycolic acid (PLGA) has been widely used as a scaffold material for bone tissue engineering applications. 3D sponge-like porous scaffolds have previously been generated through a solvent casting and salt leaching technique. In this study, polymer-ceramic composite scaffolds were created

  2. Environmental Durability of Reinforced Concrete Deck Girders Strengthened for Shear with Surface-Bonded Carbon Fiber-Reinforced Polymer

    Science.gov (United States)

    2009-05-01

    "This research investigated the durability of carbon fiber-reinforced polymer composites (CFRP) used for shear strengthening reinforced concrete deck girders. Large beams were used to avoid accounting for size effects in the data analysis. The effort...

  3. Environmental durability of reinforced concrete deck girders strengthened for shear with surface bonded carbon fiber-reinforced polymer : final report.

    Science.gov (United States)

    2009-05-01

    This research investigated the durability of carbon fiber-reinforced polymer composites (CFRP) used for shear strengthening reinforced : concrete deck girders. Large beams were used to avoid accounting for size effects in the data analysis. The effor...

  4. Selective laser sintering of hydroxyapatite reinforced polyethylene composites for bioactive implants and tissue scaffold development.

    Science.gov (United States)

    Hao, L; Savalani, M M; Zhang, Y; Tanner, K E; Harris, R A

    2006-05-01

    Selective laser sintering (SLS) has been investigated for the production of bioactive implants and tissue scaffolds using composites of high-density polyethylene (HDPE) reinforced with hydroxyapatite (HA) with the aim of achieving the rapid manufacturing of customized implants. Single-layer and multilayer block specimens made of HA-HDPE composites with 30 and 40 vol % HA were sintered successfully using a CO2 laser sintering system. Laser power and scanning speed had a significant effect on the sintering behaviour. The degree of particle fusion and porosity were influenced by the laser processing parameters, hence control can be attained by varying these parameters. Moreover, the SLS processing allowed exposure of HA particles on the surface of the composites and thereby should provide bioactive products. Pores existed in the SLS-fabricated composite parts and at certain processing parameters a significant fraction of the pores were within the optimal sizes for tissue regeneration. The results indicate that the SLS technique has the potential not only to fabricate HA-HDPE composite products but also to produce appropriate features for their application as bioactive implants and tissue scaffolds.

  5. Environmental Degradation of Fiber-Reinforced Polymer Fasteners in Wood

    Science.gov (United States)

    Samuel L. Zelinka; Douglas R. Rammer

    2013-01-01

    This paper examines the durability of fiber-reinforced polymer (FRP) nails in treated wood. The FRP nails were exposed to four conditions: (1) accelerated weathering, consisting of exposure to ultraviolet light and condensation; (2) 100% relative humidity (RH); (3) being driven into untreated wood and exposed to 100% RH; and (4) being driven into wood treated with...

  6. Mechanical properties of natural fibre reinforced polymer composites

    Indian Academy of Sciences (India)

    In the present communication, a study on the synthesis and mechanical properties of new series of green composites involving Hibiscus sabdariffa fibre as a reinforcing material in urea–formaldehyde (UF) resin based polymer matrix has been reported. Static mechanical properties of randomly oriented intimately mixed ...

  7. Preparation and properties of in-situ growth of carbon nanotubes reinforced hydroxyapatite coating for carbon/carbon composites.

    Science.gov (United States)

    Liu, Shoujie; Li, Hejun; Su, Yangyang; Guo, Qian; Zhang, Leilei

    2017-01-01

    Carbon nanotubes (CNTs) possess excellent mechanical properties for their role playing in reinforcement as imparting strength to brittle hydroxyapatite (HA) bioceramic coating. However, there are few reports relating to the in-situ grown carbon nanotubes reinforced hydroxyapatite (CNTs-HA) coating. Here we demonstrate the potential application in reinforcing biomaterials by an attempt to use in-situ grown of CNTs strengthen HA coating, using a combined method composited of injection chemical vapor deposition (ICVD) and pulsed electrodeposition. The microstructure, phases and chemical compositions of CNTs-HA coatings were characterized by various advanced methods. The scanning electron microscopy (SEM) images indicated that CNTs-HA coatings avoided the inhomogeneous dispersion of CNTs inside HA coating. The result show that the interfacial shear strength between CNTs-HA coating and the C/C composite matrix reaches to 12.86±1.43MPa. Potenitodynamic polarization and electrochemical impedance spectroscopy (EIS) studies show that the content of CNTs affects the corrosion resistance of CNTs-HA coating. Cell culturing and simulated body fluid test elicit the biocompatibility with living cells and bioactivity of CNTs-HA coatings, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Additive manufacturing of short and mixed fibre-reinforced polymer

    Energy Technology Data Exchange (ETDEWEB)

    Lewicki, James; Duoss, Eric B.; Rodriguez, Jennifer Nicole; Worsley, Marcus A.; King, Michael J.

    2018-01-09

    Additive manufacturing of a fiber-reinforced polymer (FRP) product using an additive manufacturing print head; a reservoir in the additive manufacturing print head; short carbon fibers in the reservoir, wherein the short carbon fibers are randomly aligned in the reservoir; an acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin in the reservoir, wherein the short carbon fibers are dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin; a tapered nozzle in the additive manufacturing print head operatively connected to the reservoir, the tapered nozzle produces an extruded material that forms the fiber-reinforced polymer product; baffles in the tapered nozzle that receive the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin with the short carbon fibers dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin; and a system for driving the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin with the short carbon fibers dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin from the reservoir through the tapered nozzle wherein the randomly aligned short carbon fibers in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin are aligned by the baffles and wherein the extruded material has the short carbon fibers aligned in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin that forms the fiber-reinforced polymer product.

  9. Tests on reinforced concrete slabs with cut-out openings strengthened with fibre-reinforced polymers

    OpenAIRE

    Floruţ, Sorin-Codruţ; Sas, Gabriel; Popescu, Cosmin; Stoian, Valeriu

    2014-01-01

    This paper presents the results of experimental investigations on reinforced concrete slabs strengthened using fibre-reinforced polymers (FRP). Eight tests were carried out on four two-way slabs, with and without cut-out openings. Investigations on slabs with cut-outs revealed that the FRP can be placed only around the edges of the cut-out when retrofitting the slabs whereas, in the situation of inserting cut-outs combined with increased demands of capacity, it is necessary to apply FRP compo...

  10. ENVIRONMENTAL IMPACT OF FIBRE-REINFORCED POLYMER STRENGTHENING SOLUTIONS OF REINFORCED CONCRETE COLUMNS

    Directory of Open Access Journals (Sweden)

    Sebastian George MAXINEASA

    2015-11-01

    Full Text Available The construction sector is considered by many as one of the key factors in fulfilling the three dimensions of sustainability. Notwithstanding its indisputable influence over economy and society at large, the statement above is most importantly justified by the massive impact the construction industry exerts over the environment. Strengthening existing reinforced concrete structures with composites and reusing them instead of building new ones is one of the ways by which the impact of the built environment over the natural one can be successfully decreased. This paper aims at determining if the extension of the life span of the reinforced concrete columns by applying different carbon fibre-reinforced polymer (CFRP strengthening systems can be considered a viable solution in terms of the ecological dimension of sustainability. The results obtained after conducting Life Cycle Assessment (LCA studies encourage the usage of the composite systems hereby analysed in the context of achieving the environmental aspect of sustainability in the construction sector.

  11. Flexural strengthening of Reinforced Concrete (RC Beams Retrofitted with Corrugated Glass Fiber Reinforced Polymer (GFRP Laminates

    Directory of Open Access Journals (Sweden)

    Aravind N.

    2015-01-01

    Full Text Available Strengthening the structural members of old buildings using advanced materials is a contemporary research in the field of repairs and rehabilitation. Many researchers used plain Glass Fiber Reinforced Polymer (GFRP sheets for strengthening Reinforced Concrete (RC beams. In this research work, rectangular corrugated GFRP laminates were used for strengthening RC beams to achieve higher flexural strength and load carrying capacity. Type and dimensions of corrugated profile were selected based on preliminary study using ANSYS software. A total of twenty one beams were tested to study the load carrying capacity of control specimens and beams strengthened with plain sheets and corrugated laminates using epoxy resin. This paper presents the experimental and theoretical study on flexural strengthening of Reinforced Concrete (RC beams using corrugated GFRP laminates and the results are compared. Mathematical models were developed based on the experimental data and then the models were validated.

  12. Flexural strengthening of Reinforced Concrete (RC) Beams Retrofitted with Corrugated Glass Fiber Reinforced Polymer (GFRP) Laminates

    Science.gov (United States)

    Aravind, N.; Samanta, Amiya K.; Roy, Dilip Kr. Singha; Thanikal, Joseph V.

    2015-01-01

    Strengthening the structural members of old buildings using advanced materials is a contemporary research in the field of repairs and rehabilitation. Many researchers used plain Glass Fiber Reinforced Polymer (GFRP) sheets for strengthening Reinforced Concrete (RC) beams. In this research work, rectangular corrugated GFRP laminates were used for strengthening RC beams to achieve higher flexural strength and load carrying capacity. Type and dimensions of corrugated profile were selected based on preliminary study using ANSYS software. A total of twenty one beams were tested to study the load carrying capacity of control specimens and beams strengthened with plain sheets and corrugated laminates using epoxy resin. This paper presents the experimental and theoretical study on flexural strengthening of Reinforced Concrete (RC) beams using corrugated GFRP laminates and the results are compared. Mathematical models were developed based on the experimental data and then the models were validated.

  13. New generation fiber reinforced polymer composites incorporating carbon nanotubes

    Science.gov (United States)

    Soliman, Eslam

    The last five decades observed an increasing use of fiber reinforced polymer (FRP) composites as alternative construction materials for aerospace and infrastructure. The high specific strength of FRP attracted its use as non-corrosive reinforcement. However, FRP materials were characterized with a relatively low ductility and low shear strength compared with steel reinforcement. On the other hand, carbon nanotubes (CNTs) have been introduced in the last decade as a material with minimal defect that is capable of increasing the mechanical properties of polymer matrices. This dissertation reports experimental investigations on the use of multi-walled carbon nanotubes (MWCNTs) to produce a new generation of FRP composites. The experiments showed significant improvements in the flexure properties of the nanocomposite when functionalized MWCNTs were used. In addition, MWCNTs were used to produce FRP composites in order to examine static, dynamic, and creep behavior. The MWCNTs improved the off-axis tension, off-axis flexure, FRP lap shear joint responses. In addition, they reduced the creep of FRP-concrete interface, enhanced the fracture toughness, and altered the impact resistance significantly. In general, the MWCNTs are found to affect the behaviour of the FRP composites when matrix failure dominates the behaviour. The improvement in the mechanical response with the addition of low contents of MWCNTs would benefit many industrial and military applications such as strengthening structures using FRP composites, composite pipelines, aircrafts, and armoured vehicles.

  14. A novel surface imprinted polymer/magnetic hydroxyapatite nanocomposite for selective dibenzothiophene scavenging

    Science.gov (United States)

    Ali, Hager R.; El-Maghrabi, Heba H.; Zahran, Fouad; Moustafa, Yasser Mohamed

    2017-12-01

    Highly selective adsorbent for dibenzothiophene (DBT) was successfully designed and prepared. Molecularly imprinted polymer (MIP) and magnetic hydroxyapatite (MHAP) were used as building blocks for the novel nanocomposite adsorbent. MIP/MHAP was synthesized by grafting polymerization and surface molecular imprinting using DBT as a template molecule. The microstructure and morphology of the designed nanoadsorbent were examined via FTIR, SEM and VSM. Specific surface area and pore size distribution were determined by Quantachrome Nova 3200S automated gas sorption apparatus. Additionally, static adsorption experiments, isotherms and selective recognition adsorption studies were carried out. Reversed-phase high performance liquid chromatography (RP-HPLC) was used to determine DBT. The experimental data exhibits excellent adsorption capacity for DBT reaches 247 mg/g within 60 min. Competitive adsorption results proved that MIP/MHAP have a greater affinity towards DBT molecules than benzothiophene analogues. Pseudo-second-order model and the Langmuir isotherm were used to describe the adsorption process.

  15. Highly accelerated lifetime for externally applied bond critical fiber-reinforced polymer (FRP) infrastructure materials.

    Science.gov (United States)

    2014-03-01

    This report describes a research project to investigate accelerated aging protocols for fiber-reinforced : polymer (FRP) reinforcement of concrete. This research was conducted in three stages. In the first : stage, various spectroscopic techniques we...

  16. Fique Fabric: A Promising Reinforcement for Polymer Composites

    Directory of Open Access Journals (Sweden)

    Sergio Neves Monteiro

    2018-02-01

    Full Text Available A relatively unknown natural fiber extracted from the leaves of the fique plant, native of the South American Andes, has recently shown potential as reinforcement of polymer composites for engineering applications. Preliminary investigations indicated a promising substitute for synthetic fibers, competing with other well-known natural fibers. The fabric made from fique fibers have not yet been investigated as possible composite reinforcement. Therefore, in the present work a more thorough characterization of fique fabric as a reinforcement of composites with a polyester matrix was performed. Thermal mechanical properties of fique fabric composites were determined by dynamic mechanical analysis (DMA. The ballistic performance of plain woven fique fabric-reinforced polyester matrix composites was investigated as a second layer in a multilayered armor system (MAS. The results revealed a sensible improvement in thermal dynamic mechanical behavior. Both viscoelastic stiffness and glass transition temperature were increased with the amount of incorporated fique fabric. In terms of ballistic results, the fique fabric composites present a performance similar to that of the much stronger KevlarTM as an MAS second layer with the same thickness. A cost analysis indicated that armor vests with fique fabric composites as an MAS second layer would be 13 times less expensive than a similar creation made with Kevlar™.

  17. Self Healing Fibre-reinforced Polymer Composites: an Overview

    Science.gov (United States)

    Bond, Ian P.; Trask, Richard S.; Williams, Hugo R.; Williams, Gareth J.

    Lightweight, high-strength, high-stiffness fibre-reinforced polymer composite materials are leading contenders as component materials to improve the efficiency and sustainability of many forms of transport. For example, their widespread use is critical to the success of advanced engineering applications, such as the Boeing 787 and Airbus A380. Such materials typically comprise complex architectures of fine fibrous reinforcement e.g. carbon or glass, dispersed within a bulk polymer matrix, e.g. epoxy. This can provide exceptionally strong, stiff, and lightweight materials which are inherently anisotropic, as the fibres are usually arranged at a multitude of predetermined angles within discrete stacked 2D layers. The direction orthogonal to the 2D layers is usually without reinforcement to avoid compromising in-plane performance, which results in a vulnerability to damage in the polymer matrix caused by out-of-plane loading, i.e. impact. Their inability to plastically deform leaves only energy absorption via damage creation. This damage often manifests itself internally within the material as intra-ply matrix cracks and inter-ply delaminations, and can thus be difficult to detect visually. Since relatively minor damage can lead to a significant reduction in strength, stiffness and stability, there has been some reticence by designers for their use in safety critical applications, and the adoption of a `no growth' approach (i.e. damage propagation from a defect constitutes failure) is now the mindset of the composites industry. This has led to excessively heavy components, shackling of innovative design, and a need for frequent inspection during service (Richardson 1996; Abrate 1998).

  18. Finite element analysis of Polymer reinforced CRC columns under close-in detonation

    DEFF Research Database (Denmark)

    Riisgaard, Benjamin

    2007-01-01

    Polymer reinforced Compact Reinforced Composite, PCRC, is a Fiber reinforced Densified Small Particle system, FDSP, combined with a high strength longitudinal flexural rebar arrangement laced together with polymer lacing to avoid shock initiated disintegration of the structural element under blast...... load. Experimental and numerical results of two PCRC columns subjected to close-in detonation are presented in this paper. Additionally, a LS-DYNA material model suitable for predicting the response of Polymer reinforced Compact Reinforced Concrete improved for close-in detonation and a description...

  19. Effects of moisture on glass fiber-reinforced polymer composites

    DEFF Research Database (Denmark)

    Alzamora Guzman, Vladimir Joel; Brøndsted, Povl

    2015-01-01

    Glass fiber polymer composites are used in wind turbine blades because of their high-specific strength and stiffness, good fatigue properties, and low cost. The wind industry is moving offshore to satisfy economies of scale with larger turbines. High humidity in this environment degrades mechanical...... performance of wind turbine blades over their lifetime. Here, environmental moisture conditions were simulated by immersing glass fiber-reinforced polymer specimens in salt water for a period of up to 8 years. The mechanical properties of specimens were analyzed before and after immersion to evaluate...... the degradation mechanisms. Single-fiber tensile testing was also performed at different moisture conditions. The water-diffusion mechanism was studied to quantify the diffusion coefficients as a function of salt concentration, sample geometry, and fiber direction. Three degradation mechanisms were observed...

  20. The effect of nanobioceramic reinforcement on mechanical and biological properties of Co-base alloy/hydroxyapatite nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Bahrami, M., E-mail: m.bahrami@ma.iut.ac.ir; Fathi, M.H.; Ahmadian, M.

    2015-03-01

    The goal of the present research was to fabricate, characterize, and evaluate mechanical and biological properties of Co-base alloy composites with different amounts of hydroxyapatite (HA) nanopowder reinforcement. The powder of Co–Cr–Mo alloy was mixed with different amounts of HA by ball milling and it was then cold pressed and sintered. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used. Microhardness measurement and compressive tests were also carried out. Bioactivity behavior was evaluated in simulated body fluid (SBF). A significant decrease in modulus elasticity and an increase in microhardness of the sintered composites were observed. Apatite formation on the surface of the composites showed that it could successfully convert bioinert Co–Cr–Mo alloy to bioactive type by adding 10, 15, and 20 wt.% HA which have lower modulus elasticity and higher microhardness. - Graphical abstract: The present investigation has been based on the production of composite materials based on Co–Cr–Mo alloy with different amounts of hydroxyapatite nanobioceramic powder using the powder metallurgy route. Mechanical and biological properties of the composites were investigated. A significant increase in microhardness and decrease in modulus elasticity of the sintered composites were observed. - Highlights: • Co-base alloy/hydroxyapatite composites were prepared by powder metallurgy. • Composite microhardness is improved in comparison with Co-base alloy. • Modulus elasticity decrease by about 53–63% in comparison with Co-base alloy. • Apatite nucleus is formed on the surface of composites after soaking test. • Bioinert Co–Cr–Mo alloy is successfully converted to a bioactive type.

  1. Finite element analysis of bond behavior in a steel reinforced concrete structure strengthened carbon fibre reinforced polymer (CFRP) strips

    OpenAIRE

    Pastorek, P.; Novák, P.; P. Kopas; Močilan, M.

    2017-01-01

    The article deals with the analysis of influence of carbon-fibre reinforced polymer (CFRP) on stress distribution in a steel reinforced concrete beam loaded by four-point bending flexural test. Simulation of the delamination is modelled by FEM with a cohesion zone material model. Distribution of cracks with CFRP strengthening is analysed, too. Finally, the fatigue life tests analysis was executed for the steel specimen (W.Nr. 1.0429 – concrete steel), which was used in the reinforced concrete...

  2. Preparation and characterization of mechanical properties of carbon nanotube reinforced hydroxyapatite composites consolidated by spark plasma sintering

    Science.gov (United States)

    Meng, Ye; Qiang, Wenjiang; Pang, Jingqin

    2017-09-01

    Pure hydroxyapatite(HAP) and 0.5,1,2,3,5wt% carbon nanotubes(CNTs) reinforced HAP which mixed by means of magnetic stirring method were consolidated using a spark plasma sintering(SPS) technique at SPS temperature 1273K, pressure 40MPa, and holding time 5min. The mechanical properties of pure HAP and the composites, such as hardness, flexural strength, and fracture toughness were measured. It is demonstrated that 1wt% of CNTs showed the best performance, which density was 95.78%, the Vickers hardness values was 462HV, flexural strength was 69.2MPa. Enhanced strength and toughness are attributed to the pull-out of CNTs and interfacial bonding mechanism between which and HAP during crack propagation. The flexural strength of the composites with 1 to 3wt% of CNTs were at a high level. When the content of CNTs is excessive, the mechanical properties of the material, especially flexural strength, will decrease quickly.

  3. Numerical Simulation of the Curing Process of Fiber Reinforced Polymer Composites

    OpenAIRE

    Hosseini, Amir Haji

    2013-01-01

    The curing process of Fiber reinforced polymer rebars using a two phase curing process is investigated in this work. These rebars are developed as an alternative reinforcing material in reinforced concrete. The chemical resistance and high specific strength and stiffness of these rebars make them an important subject for research

  4. Nonlinear Finite Elements Analysis of Reinforced Concrete Columns Strengthened With Carbon Fiber Reinforced Polymer (CFRP

    Directory of Open Access Journals (Sweden)

    Mazen Dewan Abdulla

    2018-02-01

    Full Text Available This paper presents the results of a study to have better understanding of structural behavior of the reinforced concrete (RC column wrapped by carbon fiber reinforced polymer (CFRP sheets. In this study, 3D F.E model has been presented using ANSYS computer program (Release 16.0 to analyze reinforced concrete columns strengthened with CFRP composites , to evaluate the gain in performance (strength and ductility due to strengthening, and to study the effect of the most important parameters such as: compressive strength of concrete, modulus of elasticity of CFRP and corner radius of square columns. Three dimensional eight-node brick element (SOLID65 was used to represent the concrete, three dimensional spar element (LINK180 represented the steel and using a three dimensional shell element (SHELL41 to represent the CFRP composites. The present study has a comparison between the analytical results from the ANSYS finite element analysis with experimental data. The results of the study show that, external bonded CFRP sheets are very effective in enhancing the axial strength and ductility of the concrete columns. Inspection of

  5. Nondestructive testing of externally reinforced structures for seismic retrofitting using flax fiber reinforced polymer (FFRP) composites

    Science.gov (United States)

    Ibarra-Castanedo, C.; Sfarra, S.; Paoletti, D.; Bendada, A.; Maldague, X.

    2013-05-01

    Natural fibers constitute an interesting alternative to synthetic fibers, e.g. glass and carbon, for the production of composites due to their environmental and economic advantages. The strength of natural fiber composites is on average lower compared to their synthetic counterparts. Nevertheless, natural fibers such as flax, among other bast fibers (jute, kenaf, ramie and hemp), are serious candidates for seismic retrofitting applications given that their mechanical properties are more suitable for dynamic loads. Strengthening of structures is performed by impregnating flax fiber reinforced polymers (FFRP) fabrics with epoxy resin and applying them to the component of interest, increasing in this way the load and deformation capacities of the building, while preserving its stiffness and dynamic properties. The reinforced areas are however prompt to debonding if the fabrics are not mounted properly. Nondestructive testing is therefore required to verify that the fabric is uniformly installed and that there are no air gaps or foreign materials that could instigate debonding. In this work, the use of active infrared thermography was investigated for the assessment of (1) a laboratory specimen reinforced with FFRP and containing several artificial defects; and (2) an actual FFRP retrofitted masonry wall in the Faculty of Engineering of the University of L'Aquila (Italy) that was seriously affected by the 2009 earthquake. Thermographic data was processed by advanced signal processing techniques, and post-processed by computing the watershed lines to locate suspected areas. Results coming from the academic specimen were compared to digital speckle photography and holographic interferometry images.

  6. A Comprehensive Study on the Mechanical and Thermal Properties of Nanoclay Reinforced Polymers at Various Temperatures

    Science.gov (United States)

    2010-03-04

    A Comprehensive Study on the Mechanical and Thermal Properties of Nanoclay Reinforced Polymers at Various Temperatures*† Selen Bayar, Ph.D...thermal properties of nanoclay reinforced polymer resins are investigated at various temperatures. The effect of nanoclay reinforcement was elicited by...The results indicate that the addition of nanoclay to PP leads to a stronger and stiffer nanocomposite. It was also found that the strength and

  7. Nano-Fiber Reinforced Enhancements in Composite Polymer Matrices

    Science.gov (United States)

    Chamis, Christos C.

    2009-01-01

    Nano-fibers are used to reinforce polymer matrices to enhance the matrix dependent properties that are subsequently used in conventional structural composites. A quasi isotropic configuration is used in arranging like nano-fibers through the thickness to ascertain equiaxial enhanced matrix behavior. The nano-fiber volume ratios are used to obtain the enhanced matrix strength properties for 0.01,0.03, and 0.05 nano-fiber volume rates. These enhanced nano-fiber matrices are used with conventional fiber volume ratios of 0.3 and 0.5 to obtain the composite properties. Results show that nano-fiber enhanced matrices of higher than 0.3 nano-fiber volume ratio are degrading the composite properties.

  8. Micromechanics of diffusion-induced damage evolution in reinforced polymers

    DEFF Research Database (Denmark)

    Abhilash, A.S.; Joshi, Shailendra P.; Mukherjee, Abhijit

    2011-01-01

    In this work we numerically investigate the nucleation and evolution of micromechanical damage in reinforced glassy polymers under transient hygro-mechanical loading. In particular, we demonstrate the role that fiber distribution plays in the evolution of overall damage due to fiber......–matrix interfacial debonding under moisture ingress. The heterogeneity of fiber distribution (clustering) is characterized by the coefficient of variation Cv of the center-to-center distances between interacting fibers, determined by identifying a cut-off radius around a typical fiber. The initial moisture diffusion...... to aggravated damage. The strong dependence of the moisture-induced damage evolution on the fiber arrangement suggests that one should not resort to using simplistic unit cell models that assume regular fiber arrangements in such cases....

  9. Performance of Sprayed Fiber Reinforced Polymer Strengthened Timber Beams

    Directory of Open Access Journals (Sweden)

    S. Talukdar

    2010-01-01

    Full Text Available A study was carried out to investigate the use of Sprayed Fiber Reinforced Polymer (SFRP for retrofit of timber beams. A total of 10-full scale specimens were tested. Two different timber preservatives and two different bonding agents were investigated. Strengthening was characterized using load deflection diagrams. Results indicate that it is possible to enhance load-carrying capacity and energy absorption characteristics using the technique of SFRP. Of the two types of preservatives investigated, the technique appears to be more effective for the case of creosote-treated specimens, where up to a 51% improvement in load-carrying capacity and a 460% increase in the energy absorption capacity were noted. Effectiveness of the bonding agent used was dependent on the type of preservative the specimen had been treated with.

  10. 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.

  11. Tapered Polymer Fiber Sensors for Reinforced Concrete Beam Vibration Detection.

    Science.gov (United States)

    Luo, Dong; Ibrahim, Zainah; Ma, Jianxun; Ismail, Zubaidah; Iseley, David Thomas

    2016-12-16

    In this study, tapered polymer fiber sensors (TPFSs) have been employed to detect the vibration of a reinforced concrete beam (RC beam). The sensing principle was based on transmission modes theory. The natural frequency of an RC beam was theoretically analyzed. Experiments were carried out with sensors mounted on the surface or embedded in the RC beam. Vibration detection results agreed well with Kistler accelerometers. The experimental results found that both the accelerometer and TPFS detected the natural frequency function of a vibrated RC beam well. The mode shapes of the RC beam were also found by using the TPFSs. The proposed vibration detection method provides a cost-comparable solution for a structural health monitoring (SHM) system in civil engineering.

  12. Durability Studies on Confined Concrete using Fiber Reinforced Polymer

    Science.gov (United States)

    Ponmalar, V.; Gettu, R.

    2014-06-01

    In this study, 24 concrete cylinders with a notch at the centre were prepared. Among them six cylinders were wrapped using single and double layers of fiber reinforced polymer; six cylinders were coated with epoxy resin; the remaining cylinders were used as a control. The cylinders were exposed to wet and dry cycling and acid (3 % H2SO4) solution for the period of 120 days. Two different concrete strengths M30 and M50 were considered for the study. It is found that the strength, ductility and failure mode of wrapped cylinders depend on number of layers and the nature of exposure conditions. It was noticed that the damage due to wet and dry cycling and acid attack was severe in control specimen than the epoxy coated and wrapped cylinders.

  13. Tapered Polymer Fiber Sensors for Reinforced Concrete Beam Vibration Detection

    Directory of Open Access Journals (Sweden)

    Dong Luo

    2016-12-01

    Full Text Available In this study, tapered polymer fiber sensors (TPFSs have been employed to detect the vibration of a reinforced concrete beam (RC beam. The sensing principle was based on transmission modes theory. The natural frequency of an RC beam was theoretically analyzed. Experiments were carried out with sensors mounted on the surface or embedded in the RC beam. Vibration detection results agreed well with Kistler accelerometers. The experimental results found that both the accelerometer and TPFS detected the natural frequency function of a vibrated RC beam well. The mode shapes of the RC beam were also found by using the TPFSs. The proposed vibration detection method provides a cost-comparable solution for a structural health monitoring (SHM system in civil engineering.

  14. Bioinspired assembly of nanoplatelets for reinforced polymer nanocomposites

    Science.gov (United States)

    Huang, Wei-Han; Dou, Xuan; Jiang, Peng

    2011-04-01

    Bio-inspired assembly of platelet particles and polyelectrolytes into ordered layered nanocomposites, which mimic the brick-and-mortar nanostructure found in the nacreous layer of mollusk shells, is of great technological importance in developing light-weight reinforced materials, separation membranes, and gas-barrier coatings. Unfortunately, the widely utilized layer-by-layer self-assembly technology is tedious in creating thick multilayered coatings. Here we report a simple filtration technology that enables the scalable production of inorganic nanoplatelets-polymer nanocomposites with layered structures. Water suspended montmorillonite (MTM) nanoclay platelets are pre-mixed with polyvinyl alcohol (PVA) aqueous solution to make stable colloidal suspensions. By using a simple vacuum filtration setup, ordered layered MTM nanoclay-PVA nanocomposites with controlled thickness can be easily prepared. The resulting selfstanding films exhibit higher tensile strength and toughness than those of natural inorganic-organic nanocomposites including nacre, bone, and dentin.

  15. Mechanical modeling of interpenetrating polymer network reinforced acrylic elastomer

    Science.gov (United States)

    Schmidt, Arne; Bergamini, Andrea; Kovacs, Gabor; Mazza, Edoardo

    2010-04-01

    Interpenetrating polymer network reinforced acrylic elastomers (IPN) offer outstanding performance in free-standing contractile dielectric elastomer actuators. This work presents the verification of a recently proposed material model for a VHB 4910 based IPN [1]. The 3D large strain material model was determined from extensive data of multiaxial mechanical experiments and allows to account for the variations in material composition of IPN-membranes. We employed inflation tests to membranes of different material composition to study the materials response in a stress state different from the one that was used to extract the material parameters. By applying the material model to finite element models we successfully validated the material model in a range of material compositions typically used for dielectric elastomer actuator applications. In combination with a characterization of electro-mechanical coupling, this 3D large strain model can be used to model IPN-based dielectric elastomer actuators.

  16. Review of Carbon Fiber Reinforced Polymer Reinforced Material in Concrete Structure

    Directory of Open Access Journals (Sweden)

    Ayuddin Ayuddin

    2016-05-01

    Full Text Available Carbon Fiber Reinforced Polymer (FRP is a material that is lightweight, strong, anti-magnetic and corrosion resistant. This material can be used as an option to replace the steel material in concrete construction or as material to improve the strength of existing construction. CFRP is quite easy to be attached to the concrete structure and proved economically used as a material for repairing damaged structures and increase the resilience of structural beams, columns, bridges and other parts of the structure against earthquakes. CFRP materials can be shaped sheet to be attached to the concrete surface. Another reason is due to the use of CFRP has a higher ultimate strength and lower weight compared to steel reinforcement so that the handling is significantly easier. Through this paper suggests that CFRP materials can be applied to concrete structures, especially on concrete columns. Through the results of experiments conducted proved that the concrete columns externally wrapped with CFRP materials can increase the strength. This treatment is obtained after testing experiments on 130 mm diameter column with a height of 700 mm with concentric loading method to collapse. The experimental results indicate that a column is wrapped externally with CFRP materials can achieve a load capacity of 250 kN compared to the concrete columns externally without CFRP material which only reached 150 kN. If the column is given internally reinforcing steel and given externally CFRP materials can reach 270 kN. It shows that CFRP materials can be used for concrete structures can even replace reinforcing steel that has been widely used in building construction in Indonesia.

  17. Electrospun Polymer Nanofibers Reinforced by Tannic Acid/Fe+++ Complexes

    Directory of Open Access Journals (Sweden)

    Weiqiao Yang

    2016-09-01

    Full Text Available We report the successful preparation of reinforced electrospun nanofibers and fibrous mats of polyvinyl alcohol (PVA via a simple and inexpensive method using stable tannic acid (TA and ferric ion (Fe+++ assemblies formed by solution mixing and pH adjustment. Changes in solution pH change the number of TA galloyl groups attached to the Fe+++ from one (pH < 2 to two (3 < pH < 6 to three (pH < 7.4 and affect the interactions between PVA and TA. At pH ~ 5.5, the morphology and fiber diameter size (FDS examined by SEM are determinant for the mechanical properties of the fibrous mats and depend on the PVA content. At an optimal 8 wt % concentration, PVA becomes fully entangled and forms uniform nanofibers with smaller FDS (p < 0.05 and improved mechanical properties when compared to mats of PVA alone and of PVA with TA (p < 0.05. Changes in solution pH lead to beads formation, more irregular FDS and poorer mechanical properties (p < 0.05. The Fe+++ inclusion does not alter the oxidation activity of TA (p > 0.05 suggesting the potential of TA-Fe+++ assemblies to reinforce polymer nanofibers with high functionality for use in diverse applications including food, biomedical and pharmaceutical.

  18. EXPERIENTIAL INVESTIGATION OF TWO-WAY CONCRETE SLABS WITH OPENINGS REINFORCED WITH GLASS FIBER REINFORCED POLYMER BARS

    Directory of Open Access Journals (Sweden)

    MOHANAD T. ABDULJALEEL

    2017-04-01

    Full Text Available This research had focused on glass fiber reinforced polymer (GFRP reinforced concrete flat plate slabs with symmetrical openings. The results of ten interior slab-column connections were presented and discussed. The test parameters are reinforcement ratio, reinforcement type, and openings location. The specimens had been tested under monotonic concentric loading up to failure. The result showed that increasing the reinforcement ratio resulted in higher punching shear-shear capacity, lower deflection, and lower reinforcement ratio. Existing of openings reduced the punching shear capacity, and increased of the deflection, for instance, when spaced of opening's location form column face up to three times of effective depth, it will be issued to increase 25% of punching strength in slab.

  19. Design Fatigue Lives of Polypropylene Fibre Reinforced Polymer Concrete Composites

    Directory of Open Access Journals (Sweden)

    Raman Bedi

    2014-09-01

    Full Text Available Flexural fatigue behavior of Poly-propylene fibre reinforced polymer concrete composites (PFRPCC has been investigated at various stress levels and the statistical analysis of the data thus obtained has been carried out. Polymer Concrete Composite (PCC samples without addition of any type of fibres were also tested for flexural fatigue.  Forty specimens of PCC and One hundred and Forty One specimens of PFRPCC containing 0.5%, 1.0% and 2.0% polypropylene fibres were tested in fatigue using a MTS servo controlled test system. Fatigue life distributions of PCC as well as PFRPCC are observed to approximately follow a two parameter Weibull distribution with correlation coefficient exceeding 0.9. The parameters of the Weibull distribution have been obtained by various methods. Failure probability, which is an important parameter in the fatigue design of materials, has been used to obtain the design fatigue lives for the material. Comparison of design fatigue life of PCC and PFRPCC has been carried out and it is observed that addition of fibres enhances the design fatigue life of PCC.

  20. Polymer-Reinforced, Non-Brittle, Lightweight Cryogenic Insulation

    Science.gov (United States)

    Hess, David M.

    2013-01-01

    The primary application for cryogenic insulating foams will be fuel tank applications for fueling systems. It is crucial for this insulation to be incorporated into systems that survive vacuum and terrestrial environments. It is hypothesized that by forming an open-cell silica-reinforced polymer structure, the foam structures will exhibit the necessary strength to maintain shape. This will, in turn, maintain the insulating capabilities of the foam insulation. Besides mechanical stability in the form of crush resistance, it is important for these insulating materials to exhibit water penetration resistance. Hydrocarbon-terminated foam surfaces were implemented to impart hydrophobic functionality that apparently limits moisture penetration through the foam. During the freezing process, water accumulates on the surfaces of the foams. However, when hydrocarbon-terminated surfaces are present, water apparently beads and forms crystals, leading to less apparent accumulation. The object of this work is to develop inexpensive structural cryogenic insulation foam that has increased impact resistance for launch and ground-based cryogenic systems. Two parallel approaches will be pursued: a silica-polymer co-foaming technique and a post foam coating technique. Insulation characteristics, flexibility, and water uptake can be fine-tuned through the manipulation of the polyurethane foam scaffold. Silicate coatings for polyurethane foams and aerogel-impregnated polyurethane foams have been developed and tested. A highly porous aerogel-like material may be fabricated using a co-foam and coated foam techniques, and can insulate at liquid temperatures using the composite foam

  1. Selenium-Substituted Hydroxyapatite/Biodegradable Polymer/Pamidronate Combined Scaffold for the Therapy of Bone Tumour

    Directory of Open Access Journals (Sweden)

    Ewa Oledzka

    2015-09-01

    Full Text Available The present study evaluated a new concept of combined scaffolds as a promising bone replacement material for patients with a bone tumour or bone metastasis. The scaffolds were composed of hydroxyapatite doped with selenium ions and a biodegradable polymer (linear or branched, and contained an active substance—bisphosphonate. For this purpose, a series of biodegradable polyesters were synthesized through a ring-opening polymerization of ε-caprolactone or d,l-lactide in the presence of 2-hydroxyethyl methacrylate (HEMA or hyperbranched 2,2-bis(hydroxymethylpropionic acid polyester-16-hydroxyl (bis-MPA initiators, substances often used in the synthesis of medical materials. The polymers were obtained with a high yield and a number-average molecular weight up to 45,300 (g/mol. The combined scaffolds were then manufactured by a direct compression of pre-synthesized hydroxyapatite doped with selenite or selenate ions, obtained polymer and pamidronate as a model drug. It was found that the kinetic release of the drug from the scaffolds tested in vitro under physiological conditions is strongly dependent on the physicochemical properties and average molecular weight of the polymers. Furthermore, there was good correlation with the hydrolytic biodegradation results of the scaffolds fabricated without drug. The preliminary findings suggest that the fabricated combined scaffolds could be effectively used for the sustained delivery of bioactive molecules at bone defect sites.

  2. Effect of overloading on fatigue performance of reinforced concrete beams strengthened with externally post-tensioned carbon-fibre-reinforced polymer tendons

    National Research Council Canada - National Science Library

    Elrefai, Ahmed; West, Jeffrey S; Soudki, Khaled A

    2008-01-01

    This paper presents the results of an experimental and analytical study of the fatigue performance of reinforced concrete beams strengthened with externally post-tensioned carbon-fibre-reinforced polymer (CFRP) tendons...

  3. Environmental durability of reinforced concrete deck girders strengthened for shear with surface-bonded carbon fiber-reinforced polymer : final report.

    Science.gov (United States)

    2009-05-01

    This research investigated the durability of carbon fiber-reinforced polymer composites (CFRP) used for shear strengthening reinforced concrete deck girders. Large beams were used to avoid accounting for size effects in the data analysis. The effort ...

  4. Aramid nanofiber-functionalized graphene nanosheets for polymer reinforcement

    Science.gov (United States)

    Fan, Jinchen; Shi, Zixing; Zhang, Lu; Wang, Jialiang; Yin, Jie

    2012-10-01

    Aramid macroscale fibers, also called Kevlar fibers, exhibit extremely high mechanical performance. Previous studies have demonstrated that bulk aramid macroscale fibers can be effectively split into aramid nanofibers (ANFs) by dissolution in dimethylsulfoxide (DMSO) in the presence of potassium hydroxide (KOH). In this paper, we first introduced the ANFs into the structure of graphene nanosheets through non-covalent functionalization through π-π stacking interactions. Aramid nanofiber-functionalized graphene sheets (ANFGS) were successfully obtained by adding the graphene oxide (GO)/DMSO dispersion into the ANFs/DMSO solution followed by reduction with hydrazine hydrate. The ANFGS, with ANFs absorbed on the surface of the graphene nanosheets, can be easily exfoliated and dispersed in N-methyl-2-pyrrolidone (NMP). Through a combination of these two ultra-strong materials, ANFs and graphene nanosheets (GS), the resultant ANFGS can act as novel nanofillers for polymer reinforcement. We used the ANFGS as an additive for reinforcing the mechanical properties of poly(methyl methacrylate) (PMMA). With a loading of 0.7 wt% of the ANFGS, the tensile strength and Young's modulus of the ANFGS/PMMA composite film approached 63.2 MPa and 3.42 GPa, which are increases of ~84.5% and ~70.6%, respectively. The thermal stabilities of ANFGS/PMMA composite films were improved by the addition of ANFGS. Additionally, the transparencies of the ANFGS/PMMA composite films have a degree of UV-shielding due to the ultraviolet light absorption of the ANFs in the ANFGS.Aramid macroscale fibers, also called Kevlar fibers, exhibit extremely high mechanical performance. Previous studies have demonstrated that bulk aramid macroscale fibers can be effectively split into aramid nanofibers (ANFs) by dissolution in dimethylsulfoxide (DMSO) in the presence of potassium hydroxide (KOH). In this paper, we first introduced the ANFs into the structure of graphene nanosheets through non

  5. Finite element analysis of bond behavior in a steel reinforced concrete structure strengthened carbon fibre reinforced polymer (CFRP strips

    Directory of Open Access Journals (Sweden)

    P. Pastorek

    2017-01-01

    Full Text Available The article deals with the analysis of influence of carbon-fibre reinforced polymer (CFRP on stress distribution in a steel reinforced concrete beam loaded by four-point bending flexural test. Simulation of the delamination is modelled by FEM with a cohesion zone material model. Distribution of cracks with CFRP strengthening is analysed, too. Finally, the fatigue life tests analysis was executed for the steel specimen (W.Nr. 1.0429 – concrete steel, which was used in the reinforced concrete beam. The fatigue test results are used to plot the fatigue life curve.

  6. Characterization and mechanical behaviour of reinforced hydroxyapatite coatings deposited by vacuum plasma spray on SS-316L alloy.

    Science.gov (United States)

    Singh, Amardeep; Singh, Gurbhinder; Chawla, Vikas

    2018-01-10

    Hydroxyapatite powder reinforced individually with 10wt percentage (wt%) of Al2O3 and ZrO2 (HA + 10wt% Al2O3 and HA + 10wt% ZrO2) was thermally sprayed onto SS-316L substrate with a bond coat of Zirconia by vacuum plasma spray (VPS) technique. The resulted coatings were heat treated at 700°C for 1h to study its effects on microstructural and mechanical properties of the deposited coatings. The characterization of the coatings was carried out using scanning electron microscope, x-ray diffraction, porosity, surface roughness and crystallinity using Rietveld analysis. The results indicated that after post coating heat treatment substantial decrease in porosity was witnessed along with significant improvement in crystallinity. Besides, the hardness across the cross-section of the coatings and bond strength was considerably improved; however the hardness of top coat was reduced owing to the loosening of un-melted and partially melted particles by diffusion process which takes place during heat treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Use of fiber reinforced polymer composite cable for post-tensioning application.

    Science.gov (United States)

    2015-08-01

    The primary objective of this research project was to assess the feasibility of the use of innovative carbon fiber reinforced : polymer (CFRP) tendons and to develop guidelines for CFRP in post-tensioned bridge applications, including segmental : bri...

  8. Monitoring long-term in-situs behavior of installed fiber reinforced polymer.

    Science.gov (United States)

    2009-06-01

    The objective of this report is to provide information on state of the art in structural health : monitoring (SHM) and its application to bridges. The most recent trends in SHM with regard to : fiber reinforced polymer (FRP) composites are discussed....

  9. Repair of impact damaged utility poles with fiber reinforced polymers (FRP), phase II.

    Science.gov (United States)

    2015-06-01

    Vehicle collisions with steel or aluminum utility poles are common occurrences that yield substantial but often repairable : damage. This project investigates the use of a fiber-reinforced polymer (FRP) composite system for in situ repair that : mini...

  10. Closed-loop performance of an actuated deformable carbon fiber reinforced polymer mirror

    Science.gov (United States)

    Wilcox, Christopher C.; Jungwirth, Matthew E. L.; Wick, David V.; Baker, Michael S.; Hobart, Clinton G.; Romeo, Robert C.; Martin, Robert N.

    2012-06-01

    The Naval Research Laboratory and Sandia National Laboratories have been actively researching the use of carbon fiber reinforced polymer material as optical elements in many optical systems. Active optical elements can be used to build an optical system capable of changing is optical zoom. We have developed a two-element optical system that uses a large diameter, thin-shelled carbon fiber reinforced polymer mirror, actuated with micro-positioning motors, and a high actuator density micro-electro-mechanical deformable mirror. Combined with a Shack-Hartmann wavefront sensor, we have optimized this actuated carbon fiber reinforced polymer deformable mirror's surface for use with a forthcoming reflective adaptive optical zoom system. In this paper, we present the preliminary results of the carbon fiber reinforced polymer deformable mirror's surface quality and the development of the actuation of it.

  11. Guidelines for using fiber-reinforced polymer composite materials to extend bridge life : research spotlight.

    Science.gov (United States)

    2014-09-01

    With a high strength-to-weight ratio, fiber-reinforced polymer : (FRP) composite fabrics have become a promising technology for : strengthening concrete bridge elements that are starting to deteriorate. : To take full advantage of the benefits of the...

  12. Development of advanced grid stiffened (AGS) fiber reinforced polymer (FRP) tube-encased concrete columns.

    Science.gov (United States)

    2013-03-01

    In this project, a new type of confining device, a latticework of interlacing fiber reinforced polymer (FRP) ribs that are jacketed by a FRP skin, is proposed, manufactured, tested, and modeled to encase concrete cylinders. This systematic study incl...

  13. The development of crashworthy rails for fiber reinforced polymer honeycomb bridge deck system.

    Science.gov (United States)

    2015-07-01

    Fiber reinforced polymer (FRP) honeycomb panels offer an efficient and rapid replacement to : concrete decks. The system consists of FRP honeycomb sandwich panels with adequate guardrails. Although : FRP bridge deck panels have already been designed ...

  14. Assessment of mechanically fastened fiber reinforced polymer (MF-FRP) strips for extending bridge service life.

    Science.gov (United States)

    2015-03-01

    The enhancement of load rating concrete structures by the installation of Fiber reinforced : polymer strips (FRP) is becoming a preferred short-term action. The addition of supplemental : tensile capacity to concrete beams by applying high tensile st...

  15. The development of crashworthy rails for fiber reinforced polymer honeycomb bridge deck system : [summary].

    Science.gov (United States)

    2015-07-01

    Fiber reinforced polymer (FRP) honeycomb panels offer an efficient and rapid : replacement to concrete decks. The system consists of FRP honeycomb sandwich panels : with adequate guardrails. Although FRP bridge deck panels have already been designed ...

  16. Polyurethane foam infill for fiber-reinforced polymer (FRP) bridge deck panels.

    Science.gov (United States)

    2014-05-01

    Although still in their infancy, fiber-reinforced polymer (FRP) bridges have shown great promise in eliminating corrosion : concerns and meeting (or exceeding) FHWAs goal of 100-year life spans for bridges. While FRP bridges are cost-effective in ...

  17. Failure of a Carbon Fiber–Reinforced Polymer Implant Used for Transforaminal Lumbar Interbody Fusion

    National Research Council Canada - National Science Library

    Sardar, Zeeshan; Jarzem, Peter

    2013-01-01

    .... During such procedures, carbon fiber–reinforced polymer (CFRP) cages are frequently utilized to fill the void created between adjacent vertebral bodies, to provide mechanical stability, and to carry graft material...

  18. Thermal diffusivity measurements on porous carbon fiber reinforced polymer tubes

    Science.gov (United States)

    Gruber, Jürgen; Gresslehner, Karl Heinz; Mayr, Günther; Hendorfer, Günther

    2017-02-01

    This work presents the application of methods for the determination of the thermal diffusivity well suited for flat bodies adapted to cylindrical bodies. Green's functions were used to get the temperature time history for small and large times, for the approach of intersecting these two straight lines. To verify the theoretical considerations noise free data are generated by finite element simulations. Furthermore effects of inhomogeneous excitation and the anisotropic heat conduction of carbon fiber reinforced polymers were taken into account in these numerical simulations. It could be shown that the intersection of the two straight lines is suitable for the determination of the thermal diffusivity, although the results have to be corrected depending on the ratio of the cylinders inner and outer radii. Inhomogeneous excitation affects the results of this approach as it lead to multidimensional heat flux. However, based on the numerical simulations a range of the azimuthal angle exists, where the thermal diffusivity is nearly independent of the angle. The method to determine the thermal diffusivity for curved geometries by the well suited Thermographic Signal Reconstruction method and taking into account deviations from the slab by a single correction factor has great advantages from an industrial point of view, just like an easy implementation into evaluation software and the Thermographic Signal Reconstruction methods rather short processing time.

  19. Adhesion between biodegradable polymers and hydroxyapatite: Relevance to synthetic bone-like materials and tissue engineering scaffolds.

    Science.gov (United States)

    Neuendorf, R E; Saiz, E; Tomsia, A P; Ritchie, R O

    2008-09-01

    Many studies are currently underway on the quest to make synthetic bone-like materials with composites of polymeric materials and hydroxyapatite (HA). In the present work, we use wetting experiments and surface tension measurements to determine the work of adhesion between biodegradable polymers and HA, with specific reference to the role of humid environments. All the polymers are found to exhibit low contact angles (polymer-HA bonds, scale directly with the results from the wetting experiments. Short-time aging (up to 30h) in a humid environment, however, has a dramatic influence on such HA/polymer interfacial strengths; specifically, water diffusion through the organic/inorganic interface and degradation of the polymer results in a marked decrease, by some 80-90%, in the bond strengths. These results cast doubt on the use of biodegradable polymers/ceramic composites for load-bearing synthetic bone-like materials, as desired optimal mechanical properties are unlikely to be met in realistic physiological environments.

  20. Multi Scale Modeling of Continuous Aramid Fiber Reinforced Polymer Matrix Composites Used in Ballistic Protection Applications

    Science.gov (United States)

    2014-11-16

    Pandurangan, B., Yen, C-.F., Cheeseman, B. A., Wang, Y., Miao, Y. & Zheng, J. Q. “ Fiber -level Modeling of Dynamic Strength of Kevlar ® KM2 Ballistic...A. “Multi-Length Scale Enriched Continuum-Level Material Model for Kevlar ®- Fiber Reinforced Polymer- Matrix Composites” Journal of Materials Engineering and Performance 22 (2013): 681-695. ... Fiber Reinforced Polymer Matrix Composites Used in Ballistic Protection Applications Clemson University Clemson SC 242 Army Research Laboratory

  1. Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant

    OpenAIRE

    Petersen, Richard C.

    2011-01-01

    Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis. In vivo bone-marrow tests with Sprague-Dawley rats reve...

  2. Nondestructive Evaluation of Advanced Fiber Reinforced Polymer Matrix Composites: A Technology Assessment

    Science.gov (United States)

    Yolken, H. Thomas; Matzkanin, George A.

    2009-01-01

    Because of their increasing utilization in structural applications, the nondestructive evaluation (NDE) of advanced fiber reinforced polymer composites continues to receive considerable research and development attention. Due to the heterogeneous nature of composites, the form of defects is often very different from a metal and fracture mechanisms are more complex. The purpose of this report is to provide an overview and technology assessment of the current state-of-the-art with respect to NDE of advanced fiber reinforced polymer composites.

  3. State-of-the-art of fiber-reinforced polymers in additive manufacturing technologies

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; Pedersen, David Bue; Tosello, Guido

    2017-01-01

    Additive manufacturing technologies have received a lot of attention in recent years for their use in multiple materials such as metals, ceramics, and polymers. The aim of this review article is to analyze the technology of fiber-reinforced polymers and its implementation with additive...... manufacturing. This article reviews recent developments, ideas, and state-of-the-art technologies in this field. Moreover, it gives an overview of the materials currently available for fiber-reinforced material technology....

  4. Proposed Methodology for Design of Carbon Fiber Reinforced Polymer Spike Anchors into Reinforced Concrete

    Energy Technology Data Exchange (ETDEWEB)

    MacFarlane, Eric Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-26

    The included methodology, calculations, and drawings support design of Carbon Fiber Reinforced Polymer (CFRP) spike anchors for securing U-wrap CFRP onto reinforced concrete Tbeams. This content pertains to an installation in one of Los Alamos National Laboratory’s facilities. The anchors are part of a seismic rehabilitation to the subject facility. The information contained here is for information purposes only. The reader is encouraged to verify all equations, details, and methodology prior to usage in future projects. However, development of the content contained here complied with Los Alamos National Laboratory’s NQA-1 quality assurance program for nuclear structures. Furthermore, the formulations and details came from the referenced published literature. This literature represents the current state of the art for FRP anchor design. Construction personnel tested the subject anchor design to the required demand level demonstrated in the calculation. The testing demonstrated the ability of the anchors noted to carry loads in excess of 15 kips in direct tension. The anchors were not tested to failure in part because of the hazards associated with testing large-capacity tensile systems to failure. The calculation, methodology, and drawing originator was Eric MacFarlane of Los Alamos National Laboratory’s (LANL) Office of Seismic Hazards and Risk Mitigation (OSHRM). The checker for all components was Mike Salmon of the LANL OSHRM. The independent reviewers of all components were Insung Kim and Loring Wyllie of Degenkolb Engineers. Note that Insung Kim contributed to the initial formulations in the calculations that pertained directly to his Doctoral research.

  5. Investigations of sewn preform characteristics and quality aspects for the manufacturing of fiber reinforced polymer composites

    OpenAIRE

    Ogale, Amol

    2017-01-01

    Sewn net-shape preform based composite manufacturing technology is widely accepted in combination with liquid composite molding technologies for the manufacturing of fiber reinforced polymer composites. The development of threedimensional dry fibrous reinforcement structures containing desired fiber orientation and volume fraction before the resin infusion is based on the predefined preforming processes. Various preform manufacturing aspects influence the overall composite m...

  6. Hysteretic Behavior of Tubular Steel Braces Having Carbon Fiber Reinforced Polymer Reinforcement Around End Net Sections

    Directory of Open Access Journals (Sweden)

    Cem Haydaroğlu

    2015-12-01

    Full Text Available This study presents an experimental investigation into the seismic retrofit of tubular steel braces using carbon fiber reinforced polymer (CFRP members. CFRP retrofitting of net sections for compact tubes are proposed for delaying potential local net section failure. A total of almost full-scale three (TB-1, TB-2, and TB-3 compact steel tubular specimens were designed per AISC specifications, constructed, and cyclically tested to fracture. Retrofitted braces, when compared to the reference specimen, developed fuller hysteretic curves. Increase in cumulative hysteretic energy dissipation and the elongation in fracture life in the specimen retrofitted with CFRP plates and CFRP sheet wraps at net sections are observed during testing. This resulted in a maximum of 82.5% more dissipated energy for compact tube specimens. Also, this retrofit provided a longer experimental fracture life (maximum 59% more. Due to fracture initiation during the last cycles, significant reductions in strength and stiffness have been obtained. No significant change (maximum 10% in the brace stiffness was observed, which could be desirable in seismic retrofit applications. Pushover analysis per FEMA 356 for the bare specimen shows that FEMA does not represent actual brace behavior in the compression side although pushover and experimental results are in good agreement in the tension side.

  7. Nanomorphology of graphene and CNT reinforced polymer and its effect on damage: Micromechanical numerical study

    DEFF Research Database (Denmark)

    Pontefisso, Alessandro; Mishnaevsky, Leon

    2016-01-01

    of nanocomposites with inclusions of arbitrary and complex shapes. The effect of curved, zigzagged, snakelike shapes of real carbon nanotubes, as well as re-stacking of graphene on the damage evolution was studied in the computational experiments based on the developed code. The potential of hybrid (carbon...... nanotubes and graphene) nanoscale reinforcement was studied with view on its effect of damage resistance. It was demonstrated that idealized, cylinder like models of carbon nanotubes in polymers lead to an underestimation of the stress concentration and damage likelihood in the nanocomposites. The main...... damage mechanisms in CNT reinforced polymers are debonding and pull-out/fiber bridging, while in graphene reinforced polymers the main role is played by crack deviation and stack splitting, with following micro-crack merging. The potential of hybrid (carbon nanotubes and graphene) nanoscale reinforcement...

  8. Challenges and opportunities of fibre-reinforced polymers in additive manufacturing with focus on industrial applications

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; Pedersen, David Bue; Tosello, Guido

    2017-01-01

    Functional parts made by additive manufacturing of polymers have entered the area of industrial applications in recent years providing a wide range of materials with various mechanical, thermal, and electrical properties. These additive manufacturing processes can be combined with known fibre......-reinforcements applying modified material parameters with the use of fibre-reinforced polymers. An increase of tensile strength and Young’s modulus result from the application of short fibres in a polymer matrix opening up perspectives for a variety of industrial applications such as injection moulding, biomedical...

  9. The Effect of Externally Retrofitted Carbon Fiber Reinforced Polymer Composites on the Ductility of Reinforced Concrete Beams

    Science.gov (United States)

    1999-05-04

    conducted in accordance with the specifications on steel tensile tests in ASTM A370 11.4.1 and 11.4.3. 5.4 Carbon Fiber Reinforced Plastics The laminates...provided by manufacturer Tensile tests on samples of both the S512 and the S812 in accordance with ASTM D3039 . The S512 test coupon was 20 in (500mm...A TRIDENT SCHOLAR PROJECT REPORT NO. 268 The Effect of Externally Retrofitted Carbon Fiber Reinforced Polymer Composites on the Ductility of

  10. Reusing recycled fibers in high-value fiber-reinforced polymer composites: Improving bending strength by surface cleaning

    OpenAIRE

    Shi, Jian; Bao, Limin; Kobayashi, Ryouhei; Kato, Jun; Kemmochi, Kiyoshi

    2012-01-01

    Glass fiber-reinforced polymer (GFRP) composites and carbon fiber-reinforced polymer (CFRP) composites were recycled using superheated steam. Recycled glass fibers (R-GFs) and recycled carbon fibers (R-CFs) were surface treated for reuse as fiber-reinforced polymer (FRP) composites. Treated R-GFs (TR-GFs) and treated R-CFs (TR-CFs) were characterized by scanning electron microscopy (SEM) and remanufactured by vacuum-assisted resin transfer molding (VARTM). Most residual resin impurities were ...

  11. A direct borohydride fuel cell based on poly(vinyl alcohol)/hydroxyapatite composite polymer electrolyte membrane

    Science.gov (United States)

    Yang, Chun-Chen; Li, Yingjeng James; Chiu, Shwu-Jer; Lee, Kuo-Tong; Chien, Wen-Chen; Huang, Ching-An

    A new poly(vinyl alcohol)/hydroxyapatite (PVA/HAP) composite polymer membrane was synthesized using a solution casting method. Alkaline direct borohydride fuel cells (DBFCs), consisting of an air cathode based on MnO 2/C inks on Ni-foam, anodes based on PtRu black and Au catalysts on Ni-foam, and the PVA/HAP composite polymer membrane, were assembled and investigated for the first time. It was demonstrated that the alkaline direct borohydride fuel cell comprised of this low-cost PVA/HAP composite polymer membrane showed good electrochemical performance. As a result, the maximum power density of the alkaline DBFC based on the PtRu anode (45 mW cm -2) proved higher than that of the DBFC based on the Au anode (33 mW cm -2) in a 4 M KOH + 1 M KBH 4 solution at ambient conditions. This novel PVA/HAP composite polymer electrolyte membrane with high ionic conductivity at the order of 10 -2 S cm -1 has great potential for alkaline DBFC applications.

  12. Effect of monomer composition of polymer matrix on flexural properties of glass fibre-reinforced orthodontic archwire

    National Research Council Canada - National Science Library

    Ohtonen, J; Vallittu, P K; Lassila, L V J

    2013-01-01

    To compare force levels obtained from glass fibre-reinforced composite (FRC) archwires. Specifically, FRC wires were compared with polymer matrices having different dimethacrylate monomer compositions...

  13. Shear Strengthening of Corbels with Carbon Fibre Reinforced Polymers (CFRP

    Directory of Open Access Journals (Sweden)

    Nawaz, A.

    2010-09-01

    Full Text Available Corbels constitute what are known as “disturbed” regions in concrete structures, where typical shear failure may be anticipated on the grounds of small shear span-to-depth ratios. The concentration of stress induced by the weight of girders on the very small loadbearing areas in corbels often causes cracking in bridges and other structures. Little experimental research can be found in the literature on the shear strengthening of corbels. In the present study, nine such members were tested. Two had no carbon fibre reinforced polymers attached, while CFRP laminates were externally bonded to the other seven, in a number of different spatial arrangements. Ultimate shear strength was found and compared for all specimens. The results showed that CFRP configuration and geometry directly affected corbel shear strength, which was higher in all the CFRPstrengthened corbels than in the controls. The highest strength values were recorded for specimens whose shear-critical area was wrapped in CFRP.

    Las ménsulas constituyen lo que conocemos como regiones de “distorsión” en las estructuras de hormigón, zonas en que pueden preverse roturas por cortante debido a las bajas relaciones luz de cortante-canto presentes en ellas. La concentración de solicitaciones producida por el peso de las vigas sobre superficies de carga muy reducidas en las ménsulas a menudo provoca el agrietamiento de puentes y otras estructuras de obra civil. En la literatura especializada sobre el refuerzo a cortante de las ménsulas existen escasos ejemplos de estudios experimentales. Para la presente investigación se han realizado ensayos con nueve elementos de este tipo. Dos de ellos no incluían polímeros reforzados con fibra de carbono (CFRP, mientras que los siete restantes llevaban láminas externas de CFRP, dispuestas siguiendo distintas configuraciones espaciales. Los resultados indican que la configuración y la disposición geométrica de los CFRP repercuten

  14. Coating nanothickness degradable films on nanocrystalline hydroxyapatite particles to improve the bonding strength between nanohydroxyapatite and degradable polymer matrix.

    Science.gov (United States)

    Nichols, Heather L; Zhang, Ning; Zhang, Jing; Shi, Donglu; Bhaduri, Sarit; Wen, Xuejun

    2007-08-01

    Hydroxyapatite (HA) nanoparticles are similar to bone apatite in size, phase composition, and crystal structure. When compared with micron-size HA particles, nano-HA possesses improved mechanical properties and superior bioactivity for promoting bone growth and regeneration. However, scaffolds fabricated from nano-HA alone cannot meet the mechanical requirements for direct-loading applications. A number of studies suggest that nanostructured composites may offer surface and/or chemical properties of native bone, and therefore represent ideal substrates to support bone regeneration. However, a common problem with nanohydroxyapatite (nano-HA)-polymer composites is the weak binding strength between the nano-HA filler and the polymer matrix since they are two different categories of materials and cannot form covalent bonds between them during the mixing process. Often, the mechanical strength of the composite is compromised due to the phase separation of the HA filler from the polymer matrix during the tissue repair process. To overcome this problem, an ultrathin degradable polymer film was grafted onto the surface of nano-HA using a radio-frequency plasma polymerization technology from acrylic acid monomers. The treated nano-HA powders are expected to bind to the polymer matrix via covalent bonds, thus enhancing the mechanical properties of the resultant composites. High-resolution transmission electron microscopy (HRTEM) experiments showed that an extremely thin polymer film (2 nm) was uniformly deposited on the surfaces of the nanoparticles. The HRTEM results were confirmed by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectroscopy (TOFSIMS). Tensile tests performed on the specimens revealed that the degradable coating had improved elastic and strength properties when compared with the nondegradable and uncoated controls. XPS and TOSIMS data revealed that more functional carboxyl groups were formed on degradable coatings than cross

  15. Experimental Study of Concrete-filled Carbon Fiber Reinforced Polymer Tube with Internal Reinforcement under Axially Loading

    OpenAIRE

    SUN Wenbin; Qiangqiang ZHU; Weizhong HE

    2014-01-01

    Comparing with the circular concrete columns confined with fiber reinforced polymer (FRP) wrap or tube, the rectilinear confined columns were reported much less. Due to the non-uniform distribution of confining pressure in the rectilinear confined columns, the FRP confinement effectiveness was significant reduced. This paper presents findings of an experimental program where nine prefabricated rectangular cross-section CFRP tubes with CFRP integrated crossties filled concrete to form concrete...

  16. Evaluation of post-fire strength of concrete flexural members reinforced with glass fiber reinforced polymer (GFRP) bars

    Science.gov (United States)

    Ellis, Devon S.

    Owing to their corrosion resistance and superior strength to weight ratio, there has been, over the past two decades, increased interest in the use of fiber-reinforced polymer (FRP) reinforcing bars in reinforced concrete structural members. The mechanical behavior of FRP reinforcement differs from that of steel reinforcement. For example, FRP reinforcement exhibit a linear stress-strain behavior until the bar ruptures and the strength, stiffness and bond properties of FRP reinforcement are affected more adversely by elevated temperatures. All structures are subject to the risk of damage by fire and fires continue to be a significant cause of damage to structures. Many structures do not collapse after being exposed to fire. The safety of the structure for any future use is dependent on the ability to accurately estimate the post-fire load capacity of the structure. Assuming that the changes, due to fire exposure, in the mechanical behavior of the GFRP reinforcing bar and concrete, and the bond between the reinforcing bar and the concrete are understood, an analytical procedure for estimating the post-fire strength of GFRP reinforced concrete flexural elements can be developed. This thesis investigates the changes in: a) tensile properties and bond of GFRP bars; and b) the flexural behavior of GFRP reinforced concrete beams flexural after being exposed to elevated temperatures up to 400°C and cooled to ambient temperature. To this end, twelve tensile tests, twelve pullout bond tests and ten four-point beam tests were performed. The data from the tests were used to formulate analytical procedures for evaluating the post-fire strength of GFRP reinforced concrete beams. The procedure produced conservative results when compared with the experimental data. In general, the residual tensile strength and modulus of elasticity of GFRP bars decrease as the exposure temperature increases. The loss in properties is however, smaller than that observed by other researchers when

  17. Articularities of Analysis and Behaviour of Concrete Beams Reinforced with Fibrous Polymer Composite Bars

    Directory of Open Access Journals (Sweden)

    N. Ţăranu

    2006-01-01

    Full Text Available Traditional steel based reinforcement systems for concrete elements are facing with serious problems mainly caused by corrosion due to chemically aggressive environments and salts used in deicing procedures, especially in case of bridge steel reinforced concrete girders. Also in some cases special applications require structural members with magnetic transparency. An alternative to this major problem has recently become the use of fiber reinforced polymer (FPR composite bars as internal reinforcement for concrete beams. The particularities of their mechanical properties are making the design process a difficult task for engineers, numerous research centers being involved in correcting this situation. The general aspects concerning the conceiving of FR.P reinforced concrete beams are firstly analyzed, compared to those reinforced with steel bars. Some results of a Finite Element Analysis, as part of a complex program which also implies full scale testing of FRP reinforced beams subjected to bending, are given and discussed in the paper. The low elasticity modulus presented by glass fiber reinforced polymer (GFRP bars does not justify its use from structural point of view when deflection is the limiting condition but for corrosive resistance reasons and special electromagnetic properties this system can be promoted.

  18. Time-Dependent Behavior of Reinforced Polymer Concrete Columns under Eccentric Axial Loading

    Directory of Open Access Journals (Sweden)

    Valentino Paolo Berardi

    2012-11-01

    Full Text Available Polymer concretes (PCs represent a promising alternative to traditional cementitious materials in the field of new construction. In fact, PCs exhibit high compressive strength and ultimate compressive strain values, as well as good chemical resistance. Within the context of these benefits, this paper presents a study on the time-dependent behavior of polymer concrete columns reinforced with different bar types using a mechanical model recently developed by the authors. Balanced internal reinforcements are considered (i.e., two bars at both the top and bottom of the cross-section. The investigation highlights relevant stress and strain variations over time and, consequently, the emergence of a significant decrease in concrete’s stiffness and strength over time. Therefore, the results indicate that deferred effects due to viscous flow may significantly affect the reliability of reinforced polymer concrete elements over time.

  19. Applications of Fiber-Reinforced Polymers in Additive Manufacturing

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; Pedersen, David Bue; Tosello, Guido

    2017-01-01

    understanding of fiber-reinforcement in additive manufacturing in terms of production and application. Vat polymerization and material extrusion techniques for composite additive manufacturing were investigated with respect of increasing adhesion between the matrix material and the fibers. Process optimization...

  20. Self-healing in single and multiple fiber(s reinforced polymer composites

    Directory of Open Access Journals (Sweden)

    Woldesenbet E.

    2010-06-01

    Full Text Available You Polymer composites have been attractive medium to introduce the autonomic healing concept into modern day engineering materials. To date, there has been significant research in self-healing polymeric materials including several studies specifically in fiber reinforced polymers. Even though several methods have been suggested in autonomic healing materials, the concept of repair by bleeding of enclosed functional agents has garnered wide attention by the scientific community. A self-healing fiber reinforced polymer composite has been developed. Tensile tests are carried out on specimens that are fabricated by using the following components: hollow and solid glass fibers, healing agent, catalysts, multi-walled carbon nanotubes, and a polymer resin matrix. The test results have demonstrated that single fiber polymer composites and multiple fiber reinforced polymer matrix composites with healing agents and catalysts have provided 90.7% and 76.55% restoration of the original tensile strength, respectively. Incorporation of functionalized multi-walled carbon nanotubes in the healing medium of the single fiber polymer composite has provided additional efficiency. Healing is found to be localized, allowing multiple healing in the presence of several cracks.

  1. Carbon nanotube buckypaper reinforced polymer composites: a review

    Directory of Open Access Journals (Sweden)

    Bruno Ribeiro

    2017-09-01

    Full Text Available Abstract This review provides valuable information about the general characteristics, processing conditions and physical properties of carbon nanotube buckypaper (BP and its polymer composites. Vacuum filtration is the most common technique used for manufacturing BP, since the carbon nanotubes are dispersed in aqueous solution with the aid of surfactant. Previous works have reported that mechanical properties of BP prepared by vacuum filtration technique are relatively weak. On the other hand, the incorporation of polymer materials in those nanostructures revealed a significant improvement in their mechanical behavior, since the impregnation between matrix and BP is optimized. Electrical conductivity of BP/polymer composites can reach values as high as 2000 S/m, which are several orders of magnitude greater than traditional CNT/polymer composites. Also, BP can improve remarkably the thermal stability of polymer matrices, opening new perspectives to use this material in fire retardant applications.

  2. Influence of the stacking sequence on the mechanical proprieties of glass fiber reinforced polymer

    Directory of Open Access Journals (Sweden)

    Bere Paul

    2017-01-01

    Full Text Available The reinforced composite materials are in a very impressive development in the last decades. In this paper the influence of the plystacking sequence of glass fiber reinforced polymer on mechanical properties is investigated. Composite material structures consist of layers from glass mat and fabrics with different disposal sequence. The mechanical properties of the manufactured composite materials have been determined by tensile and bending tests. The obtained results are used to design the optimal materials architecture.

  3. Low-Cost Nanocellulose-Reinforced High-Temperature Polymer Composites for Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Ozcan, Soydan [ORNL; Tekinalp, Halil L [ORNL; Love, Lonnie J [ORNL; Kunc, Vlastimil [ORNL; Nelson, Kim [American Process Inc.

    2016-07-13

    ORNL worked with American Process Inc. to demonstrate the potential use of bio-based BioPlus® lignin-coated cellulose nanofibrils (L-CNF) as a reinforcing agent in the development of polymer feedstock suitable for additive manufacturing. L-CNF-reinforced polylactic acid (PLA) testing coupons were prepared and up to 69% increase in tensile strength and 133% increase in elastic modulus were demonstrated.

  4. Optimizing the Flexural Strength of Beams Reinforced with Fiber Reinforced Polymer Bars Using Back-Propagation Neural Networks

    Directory of Open Access Journals (Sweden)

    Bahman O. Taha

    2015-06-01

    Full Text Available The reinforced concrete with fiber reinforced polymer (FRP bars (carbon, aramid, basalt and glass is used in places where a high ratio of strength to weight is required and corrosion is not acceptable. Behavior of structural members using (FRP bars is hard to be modeled using traditional methods because of the high non-linearity relationship among factors influencing the strength of structural members. Back-propagation neural network is a very effective method for modeling such complicated relationships. In this paper, back-propagation neural network is used for modeling the flexural behavior of beams reinforced with (FRP bars. 101 samples of beams reinforced with fiber bars were collected from literatures. Five important factors are taken in consideration for predicting the strength of beams. Two models of Multilayer Perceptron (MLP are created, first with single-hidden layer and the second with two-hidden layers. The two-hidden layer model showed better accuracy ratio than the single-hidden layer model. Parametric study has been done for two-hidden layer model only. Equations are derived to be used instead of the model and the importance of input factors is determined. Results showed that the neural network is successful in modeling the behavior of concrete beams reinforced with different types of (FRP bars.

  5. Finite element analysis and experimental verification of Polymer reinforced CRC improved for close-in detonation

    DEFF Research Database (Denmark)

    Riisgaard, Benjamin; Georgakis, Christos; Stang, Henrik

    2007-01-01

    Compact Reinforced Composite, CRC, is a high-strength cement-based composite that holds an enormous flexural and energy-absorbing capacity due to the close-spaced high strength steel reinforcement and a high-strength cement-based fiber DSP matrix. The material has been used in various constructions...... without breaching. This paper introduces an efficient method for implementing high fractions of polymer shock reinforcement in a CRC element. Experimental tests and explicit finite element analysis is used to demonstrate the potentials of this material. This paper also provides the reader...

  6. Polymer Composites Reinforced by Nanotubes as Scaffolds for Tissue Engineering

    National Research Council Canada - National Science Library

    Wang, Wei; Liao, Susan; Liu, Ming; Zhao, Qian; Zhu, Yuhe

    2014-01-01

    .... We also introduced different preparation methods of CNTs/polymer composites, such as in situ polymerization, solution mixing, melt blending, and latex technology, each of them has its own advantages.

  7. Sensitivity analysis of stress state and bond strength of fiber-reinforced polymer/concrete interface to boundary conditions in single shear pull-out test

    National Research Council Canada - National Science Library

    Mohammadi, Tayyebeh; Wan, Baolin

    2015-01-01

    The bond between fiber-reinforced polymer and concrete substrate plays a key role in the performance of concrete structures after strengthened by externally bonded fiber-reinforced polymer composite materials...

  8. An In-Depth Study on the Mechanical and Thermal Properties of Nanoclay Reinforced Polymers at Various Temperatures

    Science.gov (United States)

    2010-05-18

    Unclassified Distribution A Approved An In-Depth Study on the Mechanical and Thermal Properties of Nanoclay Reinforced Polymers at Various...Warren, Michigan 48397-5000 Abstract In this study, the mechanical properties of nanoclay reinforced polymeric resins are investigated at various...temperatures. In recent years there has been heightened interest to develop nanoclay reinforced composites due to their superior performance

  9. The morphogenetically active polymer, inorganic polyphosphate complexed with GdCl3, as an inducer of hydroxyapatite formation in vitro.

    Science.gov (United States)

    Wang, Xiaohong; Huang, Jian; Wang, Kui; Neufurth, Meik; Schröder, Heinz C; Wang, Shunfeng; Müller, Werner E G

    2016-02-15

    Inorganic polyphosphate (polyP) is a physiological polymer composed of tens to hundreds of phosphate units linked together via phosphoanhydride bonds. Here we compared the biological activity of polyP (chain length of 40 phosphate units), complexed with Gd(3+) (polyP·Gd), with the one caused by polyP (as calcium salt) and by GdCl3 alone, regarding their potencies to induce hydroxyapatite (HA) formation in SaOS-2 cells in vitro. The three compounds, GdCl3, polyP and polyP·Gd were found to be non-toxic at concentrations up to at least 30μM. Selecting a low, 5μM, concentration it was found that polyP·Gd significantly induced HA formation, as determined by Alizarin Red S staining and by quantitative determinations using that dye. Under those conditions polyP·Gd and to a smaller extent also polyP or GdCl3 (5μM each) caused HA crystal formation arranged in a nest-like pattern. Exposure of cells to polyP·Gd resulted in a strong increase in alkaline phosphatase activity; this enzyme did not cause a distinct degradation of polyP but of polyP·Gd which was extensively hydrolyzed. The morphogenetic activity of gadolinium, in the form of polyP·Gd, is underscored by the finding that this polymer causes a strong upregulation of the genes encoding morphogenetic protein-2 (BMP2) as well as collagen type I. It is concluded that polyP·Gd is not an inert polymer but acts as a morphogenetically active polymer and induces HA formation in vitro. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Density and Morphological Properties of Some Reinforced Polymers ...

    African Journals Online (AJOL)

    The morphology of some reinforced blends of Polystyrene (PS) and Polyvinyl Acetate (PVAc) were estimated by density measurements, showing a definite pattern except that the filler composition increases the densities of the blends with 30/70, 20/80 and 10/90, PS/PVAc having highest values than other compositions. Also ...

  11. STUDY OF SINGLE WALLED CARBON NANOTUBE REINFORCED POLYMER COMPOSITES BY HANSEN SOLUBILITY PARAMETERS

    DEFF Research Database (Denmark)

    Ma, Jing

    major challenges which limit the use of SWNTs for reinforced polymer composites. The main objectives of this PhD work are to design, fabricate SWNTs/polymer composites and characterize the mechanical properties of the composite materials. This study uses the Hansen solubility parameters (HSP) to predict...... transfer from polymer matrix to nanotube fillers is evaluated by Raman spectroscopy. The results are compared with the observation of the dispersion and Hansen Solubility Parameters. It is found that a good strain transfer can be obtained when the SWNTs are well dispersed and also when there is a good...

  12. Asset management business model for design, realization, and maintenance of fibre reinforced polymer bridges

    NARCIS (Netherlands)

    Sebastian, R.

    2013-01-01

    This paper particularly addresses the market implementation of Fibre Reinforced Polymer (FRP) for bridges. It presents the concept of demand and supply chain innovation as being investigated within two ongoing European collaborative research projects (FP7) titled Trans-IND and PANTURA. FRP has

  13. Preparation and characterization of glass fibers – polymers (epoxy bars (GFRP reinforced concrete for structural applications

    Directory of Open Access Journals (Sweden)

    Alkjk Saeed

    2016-06-01

    Full Text Available The paper presents some of the results from a large experimental program undertaken at the Department of Civil Engineering of Damascus University. The project aims to study the ability to reinforce and strengthen the concrete by bars from Epoxy polymer reinforced with glass fibers (GFRP and compared with reinforce concrete by steel bars in terms of mechanical properties. Five diameters of GFRP bars, and steel bars (4mm, 6mm, 8mm, 10mm, 12mm tested on tensile strength tests. The test shown that GFRP bars need tensile strength more than steel bars. The concrete beams measuring (15cm wide × 15cm deep × and 70cm long reinforced by GFRP with 0.5 vol.% ratio, then the concrete beams reinforced by steel with 0.89 vol.% ratio. The concrete beams tested on deflection test. The test shown that beams which reinforced by GFRP has higher deflection resistance, than beams which reinforced by steel. Which give more advantage to reinforced concrete by GFRP.

  14. Preparation and characterization of glass fibers - polymers (epoxy) bars (GFRP) reinforced concrete for structural applications

    Science.gov (United States)

    Alkjk, Saeed; Jabra, Rafee; Alkhater, Salem

    2016-06-01

    The paper presents some of the results from a large experimental program undertaken at the Department of Civil Engineering of Damascus University. The project aims to study the ability to reinforce and strengthen the concrete by bars from Epoxy polymer reinforced with glass fibers (GFRP) and compared with reinforce concrete by steel bars in terms of mechanical properties. Five diameters of GFRP bars, and steel bars (4mm, 6mm, 8mm, 10mm, 12mm) tested on tensile strength tests. The test shown that GFRP bars need tensile strength more than steel bars. The concrete beams measuring (15cm wide × 15cm deep × and 70cm long) reinforced by GFRP with 0.5 vol.% ratio, then the concrete beams reinforced by steel with 0.89 vol.% ratio. The concrete beams tested on deflection test. The test shown that beams which reinforced by GFRP has higher deflection resistance, than beams which reinforced by steel. Which give more advantage to reinforced concrete by GFRP.

  15. Shear Capacity of Steel and Polymer Fibre Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Kragh-Poulsen, Jens C.; Hoang, Cao Linh; Goltermann, Per

    2011-01-01

    This paper deals with the application of a plasticity model for shear strength estimation of fibre reinforced concrete beams without stirrups. When using plastic theory to shear problems in structural concrete, the so-called effective strengths are introduced, usually determined by calibrating...... the plastic solutions with tests. This approach is, however, problematic when dealing with fibre reinforced concrete (FRC), as the effective strengths depend also on the type and the amount of fibres. In this paper, it is suggested that the effective tensile strength of FRC can be determined on the basis...... of the tensile stress-crack opening relationship found from wedge splitting tests. To determine the effective compressive strength of FRC, it is proposed to adopt the formula used for conventional concrete and modify it by introducing a fibre enhancement factor to describe the effect of fibres on the compressive...

  16. Mechanical properties of natural fibre reinforced polymer composites

    Indian Academy of Sciences (India)

    Wintec

    In the present communication, a study on the synthesis and mechanical properties of new series of green composites involving .... visual similarity. 3. Results and discussion. The importance of static mechanical analysis (SMA) as a tool in the study of the behaviour of polymer biocompo- sites is of paramount importance.

  17. Polymer Microcapsules with a Fiber-Reinforced Nanocomposite Shell

    NARCIS (Netherlands)

    Sagis, L.M.C.; Ruiter, de R.; Rossier Miranda, F.J.; Ruiter, de J.; Schroën, C.G.P.H.; Aelst, van A.C.; Kieft, H.; Boom, R.M.; Linden, van der E.

    2008-01-01

    Polymer microcapsules can be used as controlled release systems in drugs or in foods. Using layer-by-layer adsorption of common food proteins and polysaccharides, we produced a new type of microcapsule with tunable strength and permeability. The shell consists of alternating layers of pectin and

  18. Electron beam irradiation in natural fibres reinforced polymers (NFRP)

    Science.gov (United States)

    Kechaou, B.; Salvia, M.; Fakhfakh, Z.; Juvé, D.; Boufi, S.; Kallel, A.; Tréheux, D.

    2008-11-01

    This study focuses on the electric charge motion in unsatured polyester and epoxy composites reinforced by natural fibres of Alfa type, treated by different coupling agents. The electric charging phenomenon is studied by scanning electron microscopy mirror effect (SEMME) coupled with the induced current method (ICM). Previously, using the same approach, glass fibre reinforced epoxy (GFRE) was studied to correlate mechanical [B. Kchaou, C. Turki, M. Salvia, Z. Fakhfakh, D. Tréheux, Composites Science and Technology 64 (2004) 1467], or tribological [B. Kchaou, C. Turki, M. Salvia, Z. Fakhfakh, D. Tréheux, Dielectric and friction behaviour of unidirectionalglass fibre reinforced epoxy (GFRE), Wear, 265 (2008) 763.] properties and dielectric properties. It was shown that the dielectric properties of the fibre-matrix interfaces play a significant role in the optimization of the composite. This result seems to be the same for natural fibre composites: the fibre-matrix interfaces allow a diffusion of the electric charges which can delocalize the polarization energy and consequently delay the damage of the composite. However, a non-suited sizing can lead to a new trapping of electric charges along these same interfaces with, as a consequence, a localization of the polarisation energy. The optimum composite is obtained for one sizing which helps, at the same time, to have a strong fibre-matrix adhesion and an easy flow of the electric charges along the interface.

  19. The effect of ion implantation on the tribomechanical properties of carbon fibre reinforced polymers

    Energy Technology Data Exchange (ETDEWEB)

    Mistica, R.; Sood, D.K. [Royal Melbourne Inst. of Tech., VIC (Australia); Janardhana, M.N. [Deakin University, Geelong, VIC (Australia). School of Engineering and Technology

    1993-12-31

    Graphite fibre reinforced epoxy composite material (GFRP) is used extensively in the aerospace and other industries for structural application. The trend is to address the 20 to 30 year life endurance of this material in service. Mechanical joints in air crafts are exposed to dynamic loads during service and wear may be experienced by the composite material joint. Generally it has been shown that graphite fibre reinforced polymers have superior wear and friction properties as compared with the unfilled polymers. In the described experiment, ion implantation was used as a novel surface treatment. Wear and friction of a polymer composite material (GFRP) was studied and ion implantation was used in order to observe the effect on the tribomechanical properties of the material. It was found that ion implantation of C on GFRP sliding against Ti changes the tribological properties of the system, and in particular decreases the coefficient of friction and wear. 4 refs., 2 figs.

  20. Stainless and Galvanized Steel, Hydrophobic Admixture and Flexible Polymer-Cement Coating Compared in Increasing Durability of Reinforced Concrete Structures

    Science.gov (United States)

    Tittarelli, Francesca; Giosuè, Chiara; Mobili, Alessandra

    2017-08-01

    The use of stainless or galvanized steel reinforcements, a hydrophobic admixture or a flexible polymer-cement coating were compared as methods to improve the corrosion resistance of sound or cracked reinforced concrete specimens exposed to chloride rich solutions. The results show that in full immersion condition, negligible corrosion rates were detected in all cracked specimens, except those treated with the flexible polymer-cement mortar as preventive method against corrosion and the hydrophobic concrete specimens. High corrosion rates were measured in all cracked specimens exposed to wet-dry cycles, except for those reinforced with stainless steel, those treated with the flexible polymer-cement coating as restorative method against reinforcement corrosion and for hydrophobic concrete specimens reinforced with galvanized steel reinforcements.

  1. SERIAL SECTIONS THROUGH A CONTINUOUS FIBER-REINFORCED POLYMER COMPOSITE

    Directory of Open Access Journals (Sweden)

    Laurent Bizet

    2011-05-01

    Full Text Available The microstructure of a unidirectional glass-fiber composite material is described seeking especially for the influence of the stitching perpendicular to the reinforcement. Serial cuts are performed through the composite and the microstructure is quantified using global parameters and linear morphological analysis. A key result is that the stitching induces variations in fibers spacing within the yarns and in the matrix volume between the yarns. This can affect noticeably the flow of the resin during the manufacturing process and also the mechanical properties of the composite.

  2. Synthesis, characterization, biocompatibility of hydroxyapatite-natural polymers nanocomposites for dentistry applications.

    Science.gov (United States)

    Chung, Jin-Hwan; Kim, Young Kyung; Kim, Kyo-Han; Kwon, Tae-Yub; Vaezmomeni, Seyede Ziba; Samiei, Mohammad; Aghazadeh, Marzyeh; Davaran, Soodabeh; Mahkam, Mehrdad; Asadi, Ghale; Akbarzadeh, Abolfazl

    2016-01-01

    Hydroxyapatite (HA), the main mineral component of bones and teeth, was synthesized by using the reaction between calcium nitrate tetrahydrate Ca(NO3)2∙4H2O and diammonium hydrogen phosphate (NH4)2HPO4 (DAHP) with a chemical precipitation method. The objective of this study is to utilize novel inorganic-organic nanocomposites for biomedical applications. HA is an inorganic component (75% w) and chitosan, alginate and albumin (Egg white) are organic components of nanocomposites (25% w). Nanocomposites were prepared in deionized water solutions, at room temperature, using a mechanical and magnetic stirrer for 48 h. The microstructure and morphology of sintered n-HAP were tested at different preheating temperature and laser sintering speed with scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR).

  3. Thermal Characteristic Of Waste-Derived Hydroxyapatite (HA) Reinforced Ultra High Molecular Weight Polyethylene (UHMWPE) Composites For Fused Deposition Modeling (FDM) Process

    Science.gov (United States)

    Ansari, Mohamad Helmi Bin Md; Ibrahim, Mohd Halim Irwan Bin

    2017-01-01

    The present study provides a hydrothermal synthesis to obtain Hydroxyapatite (HA) powder from waste eggshells. This waste-derived HA has been characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy analysis. Waste-derived HA will be reinforced the Ultra-High Molecular Weight Polyethylene (UHMWPE) to develop a material composite for biomedical applications because of impressive mechanical properties owned by UHMWPE. Main challenger is UHMWPE has an ultra-high viscosity that renders continuous melt- state processes including one of the additive manufacturing processes which is Fused Deposition Modeling (FDM). To develop this material as feedstock in FDM process, it has been overcome by blending UHMWPE with waste-derived HA as filler. It exhibit the inclusion of 50wt% HA has reduced the degradation temperature in TGA and DSC thus enhances the processability in FDM process.

  4. Size effect of concrete column retrofitted by fiber-reinforced polymer (FRP)

    Science.gov (United States)

    Zhang, Pengpeng; Xu, Xinsheng

    2017-04-01

    At present, the research on the size effect of fiber-reinforced polymer (FRP) reinforced concrete members is not enough, besides the conclusions about size effect are different. It is of great theoretical significance and engineering application value to study the size effect of FRP reinforced concrete members in this field. In this paper, the study status from two aspects containing plain concrete columns and reinforced concrete columns for the retrofitted effect were analyzed and some new problems were put forward in this field. Also the paper mainly discussed the size effect of FRP constraint ratio and column slenderness ratio on FRP retrofitted concrete columns, and the effects of different load forms of FRP reinforced concrete columns under eccentric loading, repeated loading and unloading, and horizontal cyclic loading on the size effect of FRP reinforced concrete columns, and the influence of the single factor change of FRP paste way, type, package type and the concrete strength on the FRP reinforced concrete column. Besides, the changing tendency and regularity of the size effect of FRP strengthened concrete columns under the condition of muti-factors were given.

  5. Measurement of defects in carbon fiber reinforced polymer drilled

    Directory of Open Access Journals (Sweden)

    Pascual Víctor

    2017-01-01

    Full Text Available Increasingly, fiber-reinforced materials are more widely used because of their good mechanical properties. It is usual to join pieces of these materials through screws and rivets, for which it is necessary to make a hole in the piece, usually by drilling. One of the problems of use CFRP resides in the appearance of defects due to the machining. The main defect to be taken into account is the delamination. Delamination implies poor tolerance when assembling parts, reducing the structural integrity of the part, and areas with high wear, as a series of stresses arise when mounting the screws. Much has been published about delamination and the factors that influence its appearance, so we are not going to focus on it. The present study aims to quantify and measure the defects associated with the drilling of compounds reinforced with carbon fibers, in relation to the cutting parameters used in each case. For this purpose, an optical measurement system and a posterior digital image processing will be used through Deltec Vision software.

  6. Remote activation of nanomagnetite reinforced shape memory polymer foam

    Science.gov (United States)

    Vialle, Greg; Di Prima, Matthew; Hocking, Erica; Gall, Ken; Garmestani, Hamid; Sanderson, Terry; Arzberger, Steven C.

    2009-11-01

    Shape memory polymer foams are thermally activated using remote induction of magnetic susceptor filler particles dispersed in the thermoset foam matrix. Material properties and foam performance are characterized and compared over a range of fillers, induction parameters, and packaging configurations. This investigation indicates an improvement in heating performance for increased weight percentage of filler without sacrifice in foam thermo-mechanical properties up to 10 wt% filler. Detailed analysis of the results indicates that the primary factor in improving heating performance is heat transfer between the filler nanoparticles and the bulk foam.

  7. Thermo-oxidative stability studies of PMR-15 polymer matrix composites reinforced with various fibers

    Science.gov (United States)

    Bowles, Kenneth J.

    1990-01-01

    An experimental study was conducted to measure the thermo-oxidative stability of PMR-15 polymer matrix composites reinforced with various fibers and to observe differences in the way they degrade in air. The fibers that were studied included graphite and the thermally stable Nicalon and Nextel ceramic fibers. Weight loss rates for the different composites were assessed as a function of mechanical properties, specimen geometry, fiber sizing, and interfacial bond strength. Differences were observed in rates of weight loss, matrix cracking, geometry dependency, and fiber-sizing effects. It was shown that Celion 6000 fiber-reinforced composites do not exhibit a straight-line Arrhenius relationship at temperatures above 316 C.

  8. Carbon fiber reinforced thermoplastic composites from acrylic polymer matrices: Interfacial adhesion and physical properties

    Directory of Open Access Journals (Sweden)

    H. Kishi

    2017-04-01

    Full Text Available Acrylic polymers have high potential as matrix polymers for carbon fiber reinforced thermoplastic polymers (CFRTP due to their superior mechanical properties and the fact that they can be fabricated at relatively low temperatures. We focused on improving the interfacial adhesion between carbon fibers (CFs and acrylic polymers using several functional monomers for co-polymerization with methyl methacrylate (MMA. The copolymerized acrylic matrices showed good adhesion to the CF surfaces. In particular, an acrylic copolymer with acrylamide (AAm showed high interfacial adhesive strength with CFs compared to pure PMMA, and a hydroxyethyl acrylamide (HEAA copolymer containing both amide and hydroxyl groups showed high flexural strength of the CFRTP. A 3 mol% HEAA-copolymerized CFRTP achieved a flexural strength almost twice that of pure PMMA matrix CFRTP, and equivalent to that of an epoxy matrix CFRP.

  9. Feasibility study of actuators and sensors using electroactive polymers reinforced with carbon nanotubes

    Science.gov (United States)

    Ramaratnam, Arun; Jalili, Nader

    2004-07-01

    Electro-active polymers reinforced with carbon nanotubes have attracted many researchers in the recent years. Recent activities in this area show that conducting polymers with carbon nanotubes in an electrolytic medium possess actuation and sensing properties due to the change in bond length in the carbon atoms. However, their applications are limited due to their operation in a wet medium. In this paper, we explore the feasibility of electro-active polymers with dispersed carbon nanotubes that can be used for actuation and sensing in a dry medium like air to make them viable. Different polymer composites are considered for mixing with single-walled and multi-walled carbon nanotubes manufactured by chemical vapor deposition technique. Various dispersing techniques for aligning the carbon nanotubes like smart blending and chaotic mixing are also explored. The feasibility of actuation and sensing of these composites are verified by experimentation on several macrosystems comprised of these functional nanostructures.

  10. Flexural behavior of reinforced concrete beam with polymer coated pumice

    Science.gov (United States)

    Nainggolan, Christin Remayanti; Wijatmiko, Indradi; Wibowo, Ari

    2017-09-01

    Sustainable development has become an important issue due to the increasing consideration of preserving the nature. Many alternative for coarse aggregate replacement have been investigated ranging from natural and fabricated aggregates. In this study, natural aggregate pumice was investigated since it offers lower density that give paramount benefit in reducing total building weight and hence reducing the earthquake excitation effect and optimizing the structural dimension. However, the characteristic of porous surfaces of pumice causes excessive water absorption during concrete mixing process. Therefore, to reduce the additional water, the pumice aggregates were coated with polymer. The tested specimens consisted of normal concrete beams (NCB), uncoated pumice aggregate concrete beam (UPA) and polymer coated pumice aggregate concrete beam (PCP). The objective of the research was to obtain the effect of coating on the pumice aggregate to the flexural behavior of concrete beams. The lateral load-displacement behavior, ductility and collapse mechanism were studied. The results showed that there were only marginal drop on the load-carrying capacity of the pumice aggregate beam compared to those of normal beam. Additionally, the ductility coefficient of specimens UPA and PCP decreased of 11,97% and 14,03% respectively compared to NCB, and the ultimate load capacity decreased less than 1%. Overall, the pumice aggregate showed good characteristic for replacing normal coarse aggregate.

  11. Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant.

    Science.gov (United States)

    Petersen, Richard C

    2011-05-03

    Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis. In vivo bone-marrow tests with Sprague-Dawley rats revealed far-reaching significant osseoconductivity increases from bisphenyl-polymer/carbon-fiber composites when compared to state-of-the-art titanium-6-4 alloy controls. Midtibial percent bone area measured from the implant surface increased when comparing the titanium alloy to the polymer composite from 10.5% to 41.6% at 0.8 mm, P Carbon-fiber fragments planned to occur in the test designs, instead of producing an inflammation, stimulated bone formation and increased bone integration to the implant. In addition, low-thermal polymer processing allows incorporation of minerals and pharmaceuticals for future major tissue-engineering potential.

  12. Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant

    Directory of Open Access Journals (Sweden)

    Richard C. Petersen

    2011-01-01

    Full Text Available Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis. In vivo bone-marrow tests with Sprague-Dawley rats revealed far-reaching significant osseoconductivity increases from bisphenyl-polymer/carbon-fiber composites when compared to state-of-the-art titanium-6-4 alloy controls. Midtibial percent bone area measured from the implant surface increased when comparing the titanium alloy to the polymer composite from 10.5% to 41.6% at 0.8 mm, P<10−4, and 19.3% to 77.7% at 0.1 mm, P<10−8. Carbon-fiber fragments planned to occur in the test designs, instead of producing an inflammation, stimulated bone formation and increased bone integration to the implant. In addition, low-thermal polymer processing allows incorporation of minerals and pharmaceuticals for future major tissue-engineering potential.

  13. Mussel-inspired catecholamine polymers as new sizing agents for fiber-reinforced composites

    Science.gov (United States)

    Lee, Wonoh; Lee, Jea Uk; Byun, Joon-Hyung

    2015-04-01

    Mussel-inspired catecholamine polymers (polydopamine and polynorepinephrine) were coated on the surface of carbon and glass fibers in order to increase the interfacial shear strength between fibers and polymer matrix, and consequently the interlaminar shear strength of fiber-reinforced composites. By utilizing adhesive characteristic of the catecholamine polymer, fiber-reinforced composites can become mechanically stronger than conventional composites. Since the catecholamine polymer is easily constructed on the surface by the simultaneous polymerization of its monomer under a weak basic circumstance, it can be readily coated on micro-fibers by a simple dipping process without any complex chemical treatments. Also, catecholamines can increase the surface free energy of micro-fibers and therefore, can give better wettability to epoxy resin. Therefore, catecholamine polymers can be used as versatile and effective surface modifiers for both carbon and glass fibers. Here, catecholamine-coated carbon and glass fibers exhibited higher interfacial shear strength (37 and 27% increases, respectively) and their plain woven composites showed improved interlaminar shear strength (13 and 9% increases, respectively) compared to non-coated fibers and composites.

  14. Modal analysis of additive manufactured carbon fiber reinforced polymer composite framework: Experiment and modeling

    Science.gov (United States)

    Dryginin, N. V.; Krasnoveikin, V. A.; Filippov, A. V.; Tarasov, S. Yu.; Rubtsov, V. E.

    2016-11-01

    Additive manufacturing by 3D printing is the most advanced and promising trend for making the multicomponent composites. Polymer-based carbon fiber reinforced composites demonstrate high mechanical properties combined with low weight characteristics of the component. This paper shows the results of 3D modeling and experimental modal analysis on a polymer composite framework obtained using additive manufacturing. By the example of three oscillation modes it was shown the agreement between the results of modeling and experimental modal analysis with the use of laser Doppler vibrometry.

  15. Damage evolution in nanoclay-reinforced polymers: A three-dimensional computational study

    DEFF Research Database (Denmark)

    Dai, Gaoming; Mishnaevsky, Leon

    2013-01-01

    Initiation and growth of microcracks in the nanoclay reinforced polymer composites were analyzed in numerical experiments using 3D micromechanical unit cell models. An original program code for the automatic generation of FE unit cells with multiple disk-shaped nanoplatelets, with high aspect ratio......, clustered or exfoliated, randomly arranged or inclined, was developed. A four phase model of nanocomposites which includes the effective interface between the nanoplatelets and polymer, as well as interplatelet and outer phases, was used in the simulations. Different crack growth criteria were compared...

  16. Bioinspired design and assembly of platelet reinforced polymer films.

    Science.gov (United States)

    Bonderer, Lorenz J; Studart, André R; Gauckler, Ludwig J

    2008-02-22

    Although strong and stiff human-made composites have long been developed, the microstructure of today's most advanced composites has yet to achieve the order and sophisticated hierarchy of hybrid materials built up by living organisms in nature. Clay-based nanocomposites with layered structure can reach notable stiffness and strength, but these properties are usually not accompanied by the ductility and flaw tolerance found in the structures generated by natural hybrid materials. By using principles found in natural composites, we showed that layered hybrid films combining high tensile strength and ductile behavior can be obtained through the bottom-up colloidal assembly of strong submicrometer-thick ceramic platelets within a ductile polymer matrix.

  17. A Review of the Flammability Factors of Kenaf and Allied Fibre Reinforced Polymer Composites

    Directory of Open Access Journals (Sweden)

    C. H. Lee

    2014-01-01

    Full Text Available Natural fibre is a well-known reinforcement fibre in polymer-matrix Composites (PMC lately. Natural fibre has fast growing and abundance properties which make it available at very low cost. For kenaf fibre there is long lists of research projects which have been done regarding its behaviour, and properties and modification made to it. In this paper, fire flammability is the main concern for natural fibre reinforced polymer (NFRP composites especially kenaf fibre. To estimate its flammability, a wide range of factors can be considered such as fibre content, type of matrices, pH conditions, treatment, and fire retardant (FR filler’s type. The most important criteria are the ignition time, rate of propagation, and fire behavior. thermogravimetric analysis (TGA, different scanning calorimetric (DSC, and dynamic mechanical analysis (DMA are the three most famous methods used to investigate the fire behaviour of composites.

  18. Behavior of Concrete Beams with Peel-Plied Aramid-Fiber-Reinforced Polymer Plates

    Science.gov (United States)

    Hong, Sungnam; Park, Sun-Kyu

    2016-03-01

    The effect of fiber-reinforced polymer (FRP) plates, to which a peel-ply was fastened to increase their bonding area, on the behavior of strengthened concrete beams was investigated. A total of six concrete beams were tested. For the FRP plates, aramid-fiber-reinforced polymer (AFRP) ones were used. The test variables included their surface treatment (smooth and deformed), the depth of removal of concrete cover (0 and 10 mm), and the number of the plates. Each beam was tested in four-point bending under displacement control up to failure. Based on the experimental results obtained, the effect of the peel-plied AFRP plates on the flexural behavior of the concrete beams was evaluated.

  19. Interconnectivity of macroporous molecularly imprinted polymers fabricated by hydroxyapatite-stabilized Pickering high internal phase emulsions-hydrogels for the selective recognition of protein.

    Science.gov (United States)

    Sun, Yanhua; Li, Yuqing; Xu, Jiangfeng; Huang, Ling; Qiu, Tianyun; Zhong, Shian

    2017-07-01

    Hydroxyapatite hybridized molecularly imprinted polydopamine polymers with selective recognition of bovine hemoglobin (BHb) were successfully prepared via Pickering oil-in-water high internal phase emulsions-hydrogels and molecularly imprinting technique. The emulsions were stabilized by hydroxyapatite of which the wettability was modified by 3-methacryloxypropyltrimethoxysilane. The materials were characterized by SEM, IR and TGA. The results showed that the BHb imprinted polymers based on Pickering hydrogels (Hydro-MIPs) possess macropores ranging from 20μm to 50μm, and their large numbers of amino groups and hydroxyl groups result in a favorable adsorption capacity for BHb. The maximum adsorption capacity of Hydro-MIPs for BHb was 438mg/g, 3.27 times more than that of the non-imprinted polymers (Hydro-NIPs). The results indicated that Hydro-MIPs possessing well-defined hierarchical porous structures exhibited outstanding recognition behavior towards the target protein molecules. This work provided a promising alternative method for the fabrication of polymer materials with tunable and interconnected pores structures for the separation and purification of protein in vitro. Copyright © 2017. Published by Elsevier B.V.

  20. Warpage Analysis of Electroplated Cu Films on Fiber-Reinforced Polymer Packaging Substrates

    OpenAIRE

    Cheolgyu Kim; Tae-Ik Lee; Min Sung Kim; Taek-Soo Kim

    2015-01-01

    This paper presents a warpage analysis method that predicts the warpage behavior of electroplated Cu films on glass fiber-reinforced polymer (GFRP) packaging substrates. The analysis method is performed using the following sequence: fabricate specimens for scanning 3D contours, transform 3D data into curvatures, compute the built-in stress of the film using a stress-curvature analytic model, and verify it through comparisons of the finite element method (FEM) simulations with the measured da...

  1. Carbon Fiber Reinforced Polymer with Shredded Fibers: Quasi-Isotropic Material Properties and Antenna Performance

    OpenAIRE

    Gerald Artner; Gentner, Philipp K.; Johann Nicolics; Mecklenbräuker, Christoph F.

    2017-01-01

    A carbon fiber reinforced polymer (CFRP) laminate, with the top layer consisting of shredded fibers, is proposed and manufactured. The shredded fibers are aligned randomly on the surface to achieve a more isotropic conductivity, as is desired in antenna applications. Moreover, fiber shreds can be recycled from carbon fiber composites. Conductivity, permittivity, and permeability are obtained with the Nicolson-Ross-Weir method from material samples measured inside rectangular waveguides in the...

  2. Modal analysis of additive manufactured carbon fiber reinforced polymer composite: Experiment and modeling

    Science.gov (United States)

    Krasnoveikin, V. A.; Druzhinin, N. V.; Rubtsov, V. E.; Filippov, A. V.; Tarasov, S. Yu.

    2017-12-01

    Additive manufacturing is a promising process to develop the multicomponent polymer-matrix composites. The carbon-reinforced versions of such composites possess a low weight and a high specific strength. Here we present the results of studies of numerical and experimental modal analyses of a framework structure made of a composite material by both aforementioned approaches. The numerical test results and those obtained from the laser Doppler vibrometry show the good agreement for several oscillation modes.

  3. Bioactive glass microspheres as reinforcement for improving the mechanical properties and biological performance of poly(ε-caprolactone) polymer for bone tissue regeneration.

    Science.gov (United States)

    Lei, Bo; Shin, Kwan-Ha; Noh, Da-Young; Koh, Young-Hag; Choi, Won-Young; Kim, Hyoun-Ee

    2012-05-01

    This study examined the utility of sol-gel-derived bioactive glass microspheres (BGMs) as a reinforcement to improve the mechanical properties and biological performance of poly(ε-caprolactone) (PCL) polymer. All of the PCL-BGMs composites produced, with a variety of BGMs contents (10, 20, and 30 wt %), showed a uniform distribution of the BGMs in the PCL matrix, particularly owing to their spherical shape and small size. This led to a considerable increase in the elastic modulus from 93 ± 12 MPa to 635 ± 179 MPa with increasing BGMs content from 0 to 30 wt %. Furthermore, the addition of the BGMs to the PCL polymer significantly increased the hydrophilicity of the PCL-BGMs composites, which led to a higher water absorption and degradation rate. The PCL-BGMs composite with a BGMs content of 30 wt % showed vigorous growth of apatite crystals with a high aspect ratio on its surface after soaking in the simulated body fluid for 7 days, resulting in the creation of a porous carbonate hydroxyapatite layer. Copyright © 2012 Wiley Periodicals, Inc.

  4. Failure behavior / characteristics of fabric reinforced polymer matrix composite and aluminum6061 on dynamic tensile loading

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Hyejin; Cho, Chongdu [Inha University, Incheon (Korea, Republic of)

    2017-08-15

    Composite materials are composed of multiple types of materials as reinforcement and matrix. Among them, CFRP (Carbon fiber reinforced polymer) is widely used materials in automotive and defense industry. Carbon fibers are used as a reinforcement, of which Young's modulus is in a prepreg form. In automotive industry, especially, high strain rate test is needed to measure dynamic properties, used in dynamic analysis like high inertia included simulation as a car crash. In this paper, a SHTB (Split Hopkinson tensile bar) machine is employed for estimating stress-strain curve under dynamic load condition on aluminum 6061 and CFRP. The strain rate range is about from 100 /s to 1000 /s and the number of prepreg layers of composite specimen is total eight plies which are stacked symmetrically to structure CFRP. As a result, stress / strain point data are obtained and used for simulation into stacked composites.

  5. Mechanical characterization and structural analysis of recycled fiber-reinforced-polymer resin-transfer-molded beams

    Science.gov (United States)

    Tan, Eugene Wie Loon

    1999-09-01

    The present investigation was focussed on the mechanical characterization and structural analysis of resin-transfer-molded beams containing recycled fiber-reinforced polymers. The beams were structurally reinforced with continuous unidirectional glass fibers. The reinforcing filler materials consisted entirely of recycled fiber-reinforced polymer wastes (trim and overspray). The principal resin was a 100-percent dicyclo-pentadiene unsaturated polyester specially formulated with very low viscosity for resin transfer molding. Variations of the resin transfer molding technique were employed to produce specimens for material characterization. The basic materials that constituted the structural beams, continuous-glass-fiber-reinforced, recycled-trim-filled and recycled-overspray-filled unsaturated polyesters, were fully characterized in axial and transverse compression and tension, and inplane and interlaminar shear, to ascertain their strengths, ultimate strains, elastic moduli and Poisson's ratios. Experimentally determined mechanical properties of the recycled-trim-filled and recycled-overspray-filled materials from the present investigation were superior to those of unsaturated polyester polymer concretes and Portland cement concretes. Mechanical testing and finite element analyses of flexure (1 x 1 x 20 in) and beam (2 x 4 x 40 in) specimens were conducted. These structurally-reinforced specimens were tested and analyzed in four-point, third-point flexure to determine their ultimate loads, maximum fiber stresses and mid-span deflections. The experimentally determined load capacities of these specimens were compared to those of equivalent steel-reinforced Portland cement concrete beams computed using reinforced concrete theory. Mechanics of materials beam theory was utilized to predict the ultimate loads and mid-span deflections of the flexure and beam specimens. However, these predictions proved to be severely inadequate. Finite element (fracture propagation

  6. Reinforced concrete T-beams externally prestressed with unbonded carbon fiber-reinforced polymer tendons

    DEFF Research Database (Denmark)

    Bennitz, Anders; Nilimaa, Jonny; Täljsten, Björn

    2012-01-01

    This study describes a series of experiments examining the behavior of seven beams prestressed with unbonded external carbon fiberreinforced polymer (CFRP) tendons anchored using a newly developed anchorage and post-tensioning system. The effects of varying the initial tendon depth, prestressing...... similar effects on the structural behavior of the strengthened beams; the minor differences that were observed are attributed to the difference between the modulus of elasticity of the CFRP and the steel used in the tests. The models predicted the beams' load-bearing behavior accurately but were less...

  7. Preparation, in vitro degradability, cytotoxicity, and in vivo biocompatibility of porous hydroxyapatite whisker-reinforced poly(L-lactide) biocomposite scaffolds.

    Science.gov (United States)

    Xie, Lu; Yu, Haiyang; Yang, Weizhong; Zhu, Zhuoli; Yue, Li

    2016-01-01

    Biodegradable and bioactive scaffolds with interconnected macroporous structures, suitable biodegradability, adequate mechanical property, and excellent biocompatibility have drawn increasing attention in bone tissue engineering. Hence, in this work, porous hydroxyapatite whisker-reinforced poly(L-lactide) (HA-w/PLLA) composite scaffolds with different ratios of HA and PLLA were successfully developed through compression molding and particle leaching. The microstructure, in vitro mineralization, cytocompatibility, hemocompatibility, and in vivo biocompatibility of the porous HA-w/PLLA were investigated for the first time. The SEM results revealed that these HA-w/PLLA scaffolds possessed interconnected pore structures. Compared with porous HA powder-reinforced PLLA (HA-p/PLLA) scaffolds, HA-w/PLLA scaffolds exhibited better mechanical property and in vitro bioactivity, as more formation of bone-like apatite layers were induced on these scaffolds after mineralization in SBF. Importantly, in vitro cytotoxicity displayed that porous HA-w/PLLA scaffold with HA/PLLA ratio of 1:1 (HA-w1/PLLA1) produced no deleterious effect on human mesenchymal stem cells (hMSCs), and cells performed elevated cell proliferation, indicating a good cytocompatibility. Simultaneously, well-behaved hemocompatibility and favorable in vivo biocompatibility determined from acute toxicity test and histological evaluation were also found in the porous HA-w1/PLLA1 scaffold. These findings may provide new prospects for utilizing the porous HA whisker-based biodegradable scaffolds in bone repair, replacement, and augmentation applications.

  8. Manufacturing Energy Intensity and Opportunity Analysis for Fiber-Reinforced Polymer Composites and Other Lightweight Materials

    Energy Technology Data Exchange (ETDEWEB)

    Liddell, Heather; Brueske, Sabine; Carpenter, Alberta; Cresko, Joseph

    2016-09-22

    With their high strength-to-weight ratios, fiber-reinforced polymer (FRP) composites are important materials for lightweighting in structural applications; however, manufacturing challenges such as low process throughput and poor quality control can lead to high costs and variable performance, limiting their use in commercial applications. One of the most significant challenges for advanced composite materials is their high manufacturing energy intensity. This study explored the energy intensities of two lightweight FRP composite materials (glass- and carbon-fiber-reinforced polymers), with three lightweight metals (aluminum, magnesium, and titanium) and structural steel (as a reference material) included for comparison. Energy consumption for current typical and state-of-the-art manufacturing processes were estimated for each material, deconstructing manufacturing process energy use by sub-process and manufacturing pathway in order to better understand the most energy intensive steps. Energy saving opportunities were identified and quantified for each production step based on a review of applied R&D technologies currently under development in order to estimate the practical minimum energy intensity. Results demonstrate that while carbon fiber reinforced polymer (CFRP) composites have the highest current manufacturing energy intensity of all materials considered, the large differences between current typical and state-of-the-art energy intensity levels (the 'current opportunity') and between state-of-the-art and practical minimum energy intensity levels (the 'R&D opportunity') suggest that large-scale energy savings are within reach.

  9. The Impact of the Real Anisotropy Level of Carbon Nanotubes on the Degree of Reinforcement of Polymer Nanocomposites

    Science.gov (United States)

    Kozlov, G. V.; Dolbin, I. V.

    2017-10-01

    The paper examines the mechanism of nanocomposite reinforcement in the case of PMMA / functionalized carbon nanotubes with ultra-small nanofiller content. It shows that the real anisotropy level of carbon nanotubes is determined by their structure formed in the polymer matrix of a nanocomposite. This real anisotropy level, in its turn, determines the higher than normal degree of reinforcement of the examined nanocomposites. It also demonstrates the possibility of modeling the carbon nanotube structure as a macromolecular coil of branched polymer.

  10. Evaluating the mechanical properties of E-Glass fiber/carbon fiber reinforced interpenetrating polymer networks

    Directory of Open Access Journals (Sweden)

    G. Suresh

    2015-02-01

    Full Text Available A series of vinyl ester and polyurethane interpenetrating polymer networks were prepared by changing the component ratios of VER (Vinyl ester and PU (Polyurethane and the polymerization process was confirmed with Fourier Transform infrared spectroscopy. IPN (Inter Penetrating Polymer Network - VER/PU reinforced Glass and carbon fiber composite laminates were made using the Hand lay up technique. The Mechanical properties of the E-glass and carbon fiber specimens were compared from tests including Tensile, Compressive, Flexural, ILSS (Inter Laminar Shear Strength, Impact & Head Deflection Test (HDT. The IPN Reinforced Carbon fiber specimen showed better results in all the tests than E-Glass fibre reinforced IPN laminate with same thickness of the specimen, according to ASTM standards. It was found that the combination of 60%VER and 40%PU IPN exhibits better impact strength and maximum elongation at break, but at the slight expense of mechanical properties such as tensile, compressive, flexural, ILSS properties. The morphology of the unreinforced and reinforced composites was analyzed with help of scanning electron microscopy.

  11. Effect of fabric structure and polymer matrix on flexural strength, interlaminar shear stress, and energy dissipation of glass fiber-reinforced polymer composites

    Science.gov (United States)

    We report the effect of glass fiber structure and the epoxy polymer system on the flexural strength, interlaminar shear stress (ILSS), and energy absorption properties of glass fiber-reinforced polymer (GFRP) composites. Four different GFRP composites were fabricated from two glass fiber textiles of...

  12. Strain Measurement Using Embedded Fiber Bragg Grating Sensors Inside an Anchored Carbon Fiber Polymer Reinforcement Prestressing Rod for Structural Monitoring

    DEFF Research Database (Denmark)

    Kerrouche, Abdelfateh; Boyle, William J.O.; Sun, Tong

    2009-01-01

    Results are reported from a study carried out using a series of Bragg grating based optical fiber sensors written into a very short length (60mm) optical fiber net work and integrated into carbon fiber polymer reinforcement (CFPR) rod. Such rods are used as reinforcements in concrete structures...

  13. Mechanical and in vitro performance of apatite-wollastonite glass ceramic reinforced hydroxyapatite composite fabricated by 3D-printing.

    Science.gov (United States)

    Suwanprateeb, J; Sanngam, R; Suvannapruk, W; Panyathanmaporn, T

    2009-06-01

    In situ hydroxyapatite/apatite-wollastonite glass ceramic composite was fabricated by a three dimensional printing (3DP) technique and characterized. It was found that the as-fabricated mean green strength of the composite was 1.27 MPa which was sufficient for general handling. After varying sintering temperatures (1050-1300 degrees C) and times (1-10 h), it was found that sintering at 1300 degrees C for 3 h gave the greatest flexural modulus and strength, 34.10 GPa and 76.82 MPa respectively. This was associated with a decrease in porosity and increase in densification ability of the composite resulting from liquid phase sintering. Bioactivity tested by soaking in simulated body fluid (SBF) and In Vitro toxicity studies showed that 3DP hydroxyapatite/A-W glass ceramic composite was non-toxic and bioactive. A new calcium phosphate layer was observed on the surface of the composite after soaking in SBF for only 1 day while osteoblast cells were able to attach and attain normal morphology on the surface of the composite.

  14. A Testing Platform for Durability Studies of Polymers and Fiber-reinforced Polymer Composites under Concurrent Hygrothermo-mechanical Stimuli

    Science.gov (United States)

    Gomez, Antonio; Pires, Robert; Yambao, Alyssa; La Saponara, Valeria

    2014-01-01

    The durability of polymers and fiber-reinforced polymer composites under service condition is a critical aspect to be addressed for their robust designs and condition-based maintenance. These materials are adopted in a wide range of engineering applications, from aircraft and ship structures, to bridges, wind turbine blades, biomaterials and biomedical implants. Polymers are viscoelastic materials, and their response may be highly nonlinear and thus make it challenging to predict and monitor their in-service performance. The laboratory-scale testing platform presented herein assists the investigation of the influence of concurrent mechanical loadings and environmental conditions on these materials. The platform was designed to be low-cost and user-friendly. Its chemically resistant materials make the platform adaptable to studies of chemical degradation due to in-service exposure to fluids. An example of experiment was conducted at RT on closed-cell polyurethane foam samples loaded with a weight corresponding to ~50% of their ultimate static and dry load. Results show that the testing apparatus is appropriate for these studies. Results also highlight the larger vulnerability of the polymer under concurrent loading, based on the higher mid-point displacements and lower residual failure loads. Recommendations are made for additional improvements to the testing apparatus. PMID:25548950

  15. A testing platform for durability studies of polymers and fiber-reinforced polymer composites under concurrent hygrothermo-mechanical stimuli.

    Science.gov (United States)

    Gomez, Antonio; Pires, Robert; Yambao, Alyssa; La Saponara, Valeria

    2014-12-11

    The durability of polymers and fiber-reinforced polymer composites under service condition is a critical aspect to be addressed for their robust designs and condition-based maintenance. These materials are adopted in a wide range of engineering applications, from aircraft and ship structures, to bridges, wind turbine blades, biomaterials and biomedical implants. Polymers are viscoelastic materials, and their response may be highly nonlinear and thus make it challenging to predict and monitor their in-service performance. The laboratory-scale testing platform presented herein assists the investigation of the influence of concurrent mechanical loadings and environmental conditions on these materials. The platform was designed to be low-cost and user-friendly. Its chemically resistant materials make the platform adaptable to studies of chemical degradation due to in-service exposure to fluids. An example of experiment was conducted at RT on closed-cell polyurethane foam samples loaded with a weight corresponding to ~50% of their ultimate static and dry load. Results show that the testing apparatus is appropriate for these studies. Results also highlight the larger vulnerability of the polymer under concurrent loading, based on the higher mid-point displacements and lower residual failure loads. Recommendations are made for additional improvements to the testing apparatus.

  16. Structural, compositional, mechanical characterization and biological assessment of bovine-derived hydroxyapatite coatings reinforced with MgF{sub 2} or MgO for implants functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Mihailescu, Natalia [National Institute for Lasers, Plasma and Radiation Physics, Magurele RO-077125 (Romania); Stan, G.E. [National Institute of Materials Physics, Magurele RO-077125 (Romania); Duta, L. [National Institute for Lasers, Plasma and Radiation Physics, Magurele RO-077125 (Romania); Chifiriuc, Mariana Carmen [Department of Microbiology, Faculty of Biology, Bucharest RO-060101 (Romania); Bleotu, Coralia [Stefan S. Nicolau Institute of Virology, 85 Mihai Bravu Avenue, Bucharest RO-030304 (Romania); Sopronyi, M.; Luculescu, C. [National Institute for Lasers, Plasma and Radiation Physics, Magurele RO-077125 (Romania); Oktar, F.N. [Department of Bioengineering, Faculty of Engineering, Marmara University, Goztepe, Istanbul TR-34722 (Turkey); Advance Nanomaterials Research Laboratory, Marmara University, Goztepe, Istanbul TR-34722 (Turkey); Mihailescu, I.N., E-mail: ion.mihailescu@inflpr.ro [National Institute for Lasers, Plasma and Radiation Physics, Magurele RO-077125 (Romania)

    2016-02-01

    Hydroxyapatite (HA) is a consecrated biomaterial for bone reconstruction. In the form of thin films deposited by pulsed laser technologies, it can be used to cover metallic implants aiming to increase biocompatibility and osseointegration rate. HA of animal origin (bovine, BHA) reinforced with MgF{sub 2} (2 wt.%) or MgO (5 wt.%) were used for deposition of thin coatings with improved adherence, biocompatibility and antimicrobial activity. For pulsed laser deposition experiments, a KrF* (λ = 248 nm, τ{sub FWHM} ≤ 25 ns) excimer laser source was used. The deposited structures were characterized from a physical–chemical point of view by X-Ray Diffraction, Fourier Transform Infra-Red Spectroscopy, Scanning Electron Microscopy in top- and cross-view modes, Energy Dispersive X-Ray Spectroscopy and Pull-out adherence tests. The microbiological assay using the HEp-2 cell line revealed that all target materials and deposited thin films are non-cytotoxic. We conducted tests on three strains isolated from patients with dental implants failure, i.e. Microccocus sp., Enterobacter sp. and Candida albicans sp. The most significant anti-biofilm effect against Microcococcus sp. strain, at 72 h, was obtained in the presence of BHA:MgO thin films. For Enterobacter sp. strain a superior antimicrobial activity at 72 h was noticed, in respect with simple BHA or Ti control. The enhanced antimicrobial performances, correlated with good cytocompatibility and mechanical properties recommend these biomaterials as an alternative to synthetic HA for the fabrication of reliable implant coatings for dentistry and other applications. - Highlights: • Novel biological derived HA coatings fabricated by pulsed laser deposition. • Renewable resources • Reinforcement with MgF{sub 2} and MgO improves the HA coatings' bonding strength. • Significant anti-biofilm effect obtained for MgO reinforced HA films. • Alternative low cost solutions for a new generation of dental implants.

  17. Multi-Scale CNT-Based Reinforcing Polymer Matrix Composites for Lightweight Structures

    Science.gov (United States)

    Eberly, Daniel; Ou, Runqing; Karcz, Adam; Skandan, Ganesh; Mather, Patrick; Rodriguez, Erika

    2013-01-01

    Reinforcing critical areas in carbon polymer matrix composites (PMCs), also known as fiber reinforced composites (FRCs), is advantageous for structural durability. Since carbon nanotubes (CNTs) have extremely high tensile strength, they can be used as a functional additive to enhance the mechanical properties of FRCs. However, CNTs are not readily dispersible in the polymer matrix, which leads to lower than theoretically predicted improvement in mechanical, thermal, and electrical properties of CNT composites. The inability to align CNTs in a polymer matrix is also a known issue. The feasibility of incorporating aligned CNTs into an FRC was demonstrated using a novel, yet commercially viable nanofiber approach, termed NRMs (nanofiber-reinforcing mats). The NRM concept of reinforcement allows for a convenient and safe means of incorporating CNTs into FRC structural components specifically where they are needed during the fabrication process. NRMs, fabricated through a novel and scalable process, were incorporated into FRC test panels using layup and vacuum bagging techniques, where alternating layers of the NRM and carbon prepreg were used to form the reinforced FRC structure. Control FRC test panel coupons were also fabricated in the same manner, but comprised of only carbon prepreg. The FRC coupons were machined to size and tested for flexural, tensile, and compression properties. This effort demonstrated that FRC structures can be fabricated using the NRM concept, with an increased average load at break during flexural testing versus that of the control. The NASA applications for the developed technologies are for lightweight structures for in-space and launch vehicles. In addition, the developed technologies would find use in NASA aerospace applications such as rockets, aircraft, aircraft/spacecraft propulsion systems, and supporting facilities. The reinforcing aspect of the technology will allow for more efficient joining of fiber composite parts, thus offering

  18. Morphology, thermal and mechanical properties of poly (ε-caprolactone) biocomposites reinforced with nano-hydroxyapatite decorated graphene.

    Science.gov (United States)

    Zhou, Keqing; Gao, Rui; Jiang, Saihua

    2017-06-15

    In this work, hydroxyapatite (HAP) nanorods decorated on graphene nanosheets (HAP-Gs) was synthesized by a hydrothermal method. The structure, elemental composition and morphology of the HAP-Gs hybrids were characterized by X-ray diffraction, Fourier transform infrared and Transmission electron microscopy. Subsequently, the hybrids were incorporated into poly (ε-caprolactone) (PCL) via a solution blending method. Optical images and scanning electron microscopy observation revealed not only a well dispersion of HAP-Gs hybrids but also a strong interfacial interaction between hybrids and PCL matrix. The influence of HAP-Gs hybrids on the crystallization behavior, crystal structure, thermal stability, mechanical properties and biocompatibility of the PCL nanocomposites was investigated in detail. The results showed that the crystallization temperature of PCL was enhanced obviously, but the crystal structure was not affected by the incorporation of HAP-Gs hybrids. The mechanical properties of PCL bionanocomposites were improved obviously. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. A novel silica nanotube reinforced ionic incorporated hydroxyapatite composite coating on polypyrrole coated 316L SS for implant application

    Energy Technology Data Exchange (ETDEWEB)

    Prem Ananth, K., E-mail: kpananth01@gmail.com [Department of Nanoscience and Technology, Bharathiar University, Coimbatore – 641 046 (India); Joseph Nathanael, A. [Department of Nano, Medical and Polymer Materials, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Jose, Sujin P. [Department of Materials Science and Nano engineering, Rice University, Texas 77005 (United States); School of Physics, Madurai Kamaraj University, Madurai-625021 (India); Oh, Tae Hwan [Department of Nano, Medical and Polymer Materials, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Mangalaraj, D. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore – 641 046 (India)

    2016-02-01

    An attempt has been made to deposit a novel smart ion (Sr, Zn, Mg) substituted hydroxyapatite (I-HAp) and silica nanotube (SiNTs) composite coatings on polypyrrole (PPy) coated surgical grade 316L stainless steel (316L SS) to improve its biocompatibility and corrosion resistance. The I-HAp/SiNTS/PPy bilayer coating on 316L SS was prepared by electrophoretic deposition technique. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies were carried out. These results confirmed the significant improvement of the corrosion resistance of the 316L SS alloy by the I-HAp/SiNTs/PPy bilayer composite coating. The adhesion strength and hardness test confirmed the anticipated mechanical properties of the composite. A low contact angle value revealed the hydrophilic nature. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) was used for the leach out analysis of the samples. Added to this, the bioactivity of the composite was analyzed by observing the apatite formation in the SBF solution for 7, 14, 21 and 28 days of incubation. An enhancement of in vitro osteoblast attachment and cell viability was observed, which could lead to the optimistic orthopedic and dental applications. - Highlights: • Polypyrrole (PPy) coated 316L SS substrates were fabricated using electrodeposition method. • A novel silica nanotube (SiNTs) and ionic substituted (Sr, Zn, Mg) hydroxyapatite composite (I-HAp) were prepared. • The composite (I-HAp/SiNTs) was coated on PPy coated 316L SS substrate using electrophoretic deposition. • These results are favorable for corrosion resistance and enhanced osteoblast cell attachment for bone formation.

  20. Low Velocity Impact Behavior of Basalt Fiber-Reinforced Polymer Composites

    Science.gov (United States)

    Shishevan, Farzin Azimpour; Akbulut, Hamid; Mohtadi-Bonab, M. A.

    2017-06-01

    In this research, we studied low velocity impact response of homogenous basalt fiber-reinforced polymer (BFRP) composites and then compared the impact key parameters with carbon fiber-reinforced polymer (CFRP) homogenous composites. BFRPs and CFRPs were fabricated by vacuum-assisted resin transfer molding (VARTM) method. Fabricated composites included 60% fiber and 40% epoxy matrix. Basalt and carbon fibers used as reinforcement materials were weaved in 2/2 twill textile tip in the structures of BFRP and CFRP composites. We also utilized the energy profile method to determine penetration and perforation threshold energies. The low velocity impact tests were carried out in 30, 60, 80, 100, 120 and 160 J energy magnitudes, and impact response of BFRPs was investigated by related force-deflection, force-time, deflection-time and absorbed energy-time graphics. The related impact key parameters such as maximum contact force, absorbed energy, deflection and duration time were compared with CFRPs for various impact energy levels. As a result, due to the higher toughness of basalt fibers, a better low velocity impact performance of BFRP than that of CFRP was observed. The effects of fabrication parameters, such as curing process, were studied on the low velocity impact behavior of BFRP. The results of tested new fabricated materials show that the change of fabrication process and curing conditions improves the impact behavior of BFRPs up to 13%.

  1. Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    Science.gov (United States)

    Cox, Sarah B.; Lui, Donovan; Gou, Jihua

    2014-01-01

    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200C, beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

  2. Processing and Material Characterization of Continuous Basalt Fiber Reinforced Ceramic Matrix Composites Using Polymer Derived Ceramics.

    Science.gov (United States)

    Cox, Sarah B.

    2014-01-01

    The need for high performance vehicles in the aerospace industry requires materials which can withstand high loads and high temperatures. New developments in launch pads and infrastructure must also be made to handle this intense environment with lightweight, reusable, structural materials. By using more functional materials, better performance can be seen in the launch environment, and launch vehicle designs which have not been previously used can be considered. The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer matrix composites can be used for temperatures up to 260C. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in the composites. In this study, continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. The oxyacetylene torch testing and three point bend testing have been performed on test panels and the test results are presented.

  3. A Review on Natural Fiber Reinforced Polymer Composite and Its Applications

    Directory of Open Access Journals (Sweden)

    Layth Mohammed

    2015-01-01

    Full Text Available Natural fibers are getting attention from researchers and academician to utilize in polymer composites due to their ecofriendly nature and sustainability. The aim of this review article is to provide a comprehensive review of the foremost appropriate as well as widely used natural fiber reinforced polymer composites (NFPCs and their applications. In addition, it presents summary of various surface treatments applied to natural fibers and their effect on NFPCs properties. The properties of NFPCs vary with fiber type and fiber source as well as fiber structure. The effects of various chemical treatments on the mechanical and thermal properties of natural fibers reinforcements thermosetting and thermoplastics composites were studied. A number of drawbacks of NFPCs like higher water absorption, inferior fire resistance, and lower mechanical properties limited its applications. Impacts of chemical treatment on the water absorption, tribology, viscoelastic behavior, relaxation behavior, energy absorption flames retardancy, and biodegradability properties of NFPCs were also highlighted. The applications of NFPCs in automobile and construction industry and other applications are demonstrated. It concluded that chemical treatment of the natural fiber improved adhesion between the fiber surface and the polymer matrix which ultimately enhanced physicomechanical and thermochemical properties of the NFPCs.

  4. Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    Science.gov (United States)

    Cox, Sarah B.; Lui, Donovan; Wang, Xin; Gou, Jihua

    2014-01-01

    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000 deg C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200 deg C, Beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

  5. Experimental data on the properties of natural fiber particle reinforced polymer composite material

    Directory of Open Access Journals (Sweden)

    D. Chandramohan

    2017-08-01

    Full Text Available This paper presents an experimental study on the development of polymer bio-composites. The powdered coconut shell, walnut shells and Rice husk are used as reinforcements with bio epoxy resin to form hybrid composite specimens. The fiber compositions in each specimen are 1:1 while the resin and hardener composition 10:1 respectively. The fabricated composites were tested as per ASTM standards to evaluate mechanical properties such as tensile strength, flexural strength, shear strength and impact strength are evaluated in both with moisture and without moisture. The result of test shows that hybrid composite has far better properties than single fibre glass reinforced composite under mechanical loads. However it is found that the incorporation of walnut shell and coconut shell fibre can improve the properties.

  6. Self-reinforcement of liquid-crystal polymers at static and dynamic loading

    Science.gov (United States)

    Kudryavtseva, S. E.; Kovriga, V. V.

    1995-07-01

    The self-reinforcement effect of a solid uniaxially oriented SVM-K liquid-crystal polyamide and a copolyester of hydroxybenzoic and hydroxynaphthoic acids has been investigated by tensile-strength, stress-relaxation, and dynamic methods. The samples were prepared by spinning from lyotropic solution (SVM-K) and from a thermotropic melt (polyester). The tensile-strength and stress-relaxation tests were performed on complex fibers and the dynamic test on single fibers. The set of stress-strain curves, changing from a convex shape with two linear sections (at room temperature) to a concave shape (at high temperatures) is shown for both materials in Fig. 1. There is a pronounced difference between the deformation mechanisms at low and high strains in the stability of rigidity. At high temperatures the rigidity becomes less than the initial one during deformation and the current modulus at high strains has the same value within large ranges of temperatures and strains (Fig. 2). A low-deformation transition of another physical parameter than the yield-stress has been found. The stress-strain diagram for both investigated polymers has been generalized by using the constant value of the current modulus for the normalization of the stress value (Fig. 3). The stress-relaxation phenomena are shown to be anomalous. At high temperatures the stress-relaxation intensity decreases with increasing deformation, i.e., after deformation the polymer is characterized by a stability of rigidity which is higher than the initial value (Fig. 4). The dynamic modulus appears to increase with increasing deformation rate (Fig. 5). Due to these peculiarities the liquid-crystal polymers must be considered not only as normal high-modulus reinforcements for composite materials but also as materials, self-reinforcing under loading.

  7. Space environmental effects on LDEF low Earth orbit exposed graphite reinforced polymer matrix composites

    Science.gov (United States)

    George, Pete

    1992-01-01

    The Long Duration Exposure Facility (LDEF) was deployed on April 7, 1984 in low earth orbit (LEO) at an altitude of 482 kilometers. On board experiments experienced the harsh LEO environment including atomic oxygen (AO), ultraviolet radiation (UV), and thermal cycling. During the 5.8 year mission, the LDEF orbit decayed to 340 kilometers where significantly higher AO concentrations exist. LDEF was retrieved on January 12, 1990 from this orbit. One experiment on board LDEF was M0003, Space Effects on Spacecraft Materials. As a subset of M0003 nearly 500 samples of polymer, metal, and glass matrix composites were flown as the Advanced Composites Experiment M0003-10. The Advanced Composites Experiment is a joint effort between government and industry with the Aerospace Corporation serving as the experiment integrator. A portion of the graphite reinforced polymer matrix composites were furnished by the Boeing Defense and Space Group, Seattle, Washington. Test results and discussions for the Boeing portion of M0003-10 are presented. Experiment and specimen location on the LDEF are presented along with a quantitative summary of the pertinent exposure conditions. Matrix materials selected for the test were epoxy, polysulfone, and polyimide. These composite materials were selected due to their suitability for high performance structural capability in spacecraft applications. Graphite reinforced polymer matrix composites offer higher strength to weight ratios along with excellent dimensional stability. The Boeing space exposed and corresponding ground control composite specimens were subjected to post flight mechanical, chemical, and physical testing in order to determine any changes in critical properties and performance characteristics. Among the more significant findings are the erosive effect of atomic oxygen on leading edge exposed specimens and microcracking in non-unidirectionally reinforced flight specimens.

  8. Nano-hydroxyapatite reinforced AZ31 magnesium alloy by friction stir processing: a solid state processing for biodegradable metal matrix composites.

    Science.gov (United States)

    Ratna Sunil, B; Sampath Kumar, T S; Chakkingal, Uday; Nandakumar, V; Doble, Mukesh

    2014-04-01

    Friction stir processing (FSP) was successfully adopted to fabricate nano-hydroxyapatite (nHA) reinforced AZ31 magnesium alloy composite as well as to achieve fine grain structure. The combined effect of grain refinement and the presence of embedded nHA particles on enhancing the biomineralization and controlling the degradation of magnesium were studied. Grain refinement from 56 to ~4 and 2 μm was observed at the stir zones of FSP AZ31 and AZ31-nHA composite respectively. The immersion studies in super saturated simulated body fluid (SBF 5×) for 24 h suggest that the increased wettability due to fine grain structure and nHA particles present in the AZ31-nHA composite initiated heterogeneous nucleation which favored the early nucleation and growth of calcium-phosphate mineral phase. The nHA particles as nucleation sites initiated rapid biomineralization in the composite. After 72 h of immersion the degradation due to localized pitting was observed to be reduced by enhanced biomineralization in both the FSPed AZ31 and the composite. Also, best corrosion behavior was observed for the composite before and after immersion test. MTT assay using rat skeletal muscle (L6) cells showed negligible toxicity for all the processed and unprocessed samples. However, cell adhesion was observed to be more on the composite due to the small grain size and incorporated nHA.

  9. Development of a glass reinforced hydroxyapatite with enhanced mechanical properties. The effect of glass composition on mechanical properties and its relationship to phase changes.

    Science.gov (United States)

    Knowles, J C; Bonfield, W

    1993-12-01

    Utilizing glasses of the types xNa2O-(1-x)P2O5 and xCaO-(1-x)P2O5 (where x = 0.2, 0.3, and 0.5), a systematic study of the effect of increasing network modifying oxides in glasses was made on the mechanical properties of a glass reinforced hydroxyapatite, at glass additions of 2.5 and 5 wt%. For the soda type glass, phase changes were promoted much more readily compared to the lime type glass. This was true for both 2.5 and 5 wt% additions of glass. For the lime type glass, considerable differences between the effects of 2.5 and 5 wt% additions were seen. At 5 wt%, the increased amount of liquid phase present promotes an increased level of phase inversion to alpha and beta tricalcium phosphate. At 2.5 wt%, a larger percentage of the HA remains stable at higher temperatures. Furthermore, the effect of the composition may be seen. As the mol% of network forming oxide increases, (i.e., the Ca/P ratio moves towards 1.67, (the ratio for HA) the HA remains more stable. This is seen in the maintenance of both the HA phase and also the enhanced mechanical properties.

  10. A Smart Eddy Current Sensor Dedicated to the Nondestructive Evaluation of Carbon Fibers Reinforced Polymers.

    Science.gov (United States)

    Naidjate, Mohammed; Helifa, Bachir; Feliachi, Mouloud; Lefkaier, Iben-Khaldoun; Heuer, Henning; Schulze, Martin

    2017-08-31

    This paper propose a new concept of an eddy current (EC) multi-element sensor for the characterization of carbon fiber-reinforced polymers (CFRP) to evaluate the orientations of plies in CFRP and the order of their stacking. The main advantage of the new sensors is the flexible parametrization by electronical switching that reduces the effort for mechanical manipulation. The sensor response was calculated and proved by 3D finite element (FE) modeling. This sensor is dedicated to nondestructive testing (NDT) and can be an alternative for conventional mechanical rotating and rectangular sensors.

  11. Development of PLA hybrid yarns for biobased self-reinforced polymer composites

    Science.gov (United States)

    Köhler, T.; Gries, T.; Seide, G.

    2017-10-01

    Lightweight materials are a necessity in various industries. Lightweight design is in the key interest of the mobility sector, e.g. the automotive and aerospace industry. This trend applies also for the consumer industries, e.g. sporting goods. In addition, the worldwide demand for replacing fossil-based materials has led to a significant growth of bioplastics. Due to their low mechanical performance and durability, their use is still limited. Therefore, it is necessary to develop biobased, sustainable polymeric materials with high stiffness, high impact and high durability without impairing recyclability at a similar price level of non-biobased solutions. Biobased self-reinforced polymer composites offer these unique properties.

  12. Modeling of nano-reinforced polymer composites: Microstructure effect on Young’s modulus

    DEFF Research Database (Denmark)

    Peng, R.D.; Zhou, H.W.; Wang, H.W.

    2012-01-01

    A computational numerical-analytical model of nano-reinforced polymer composites is developed taking into account the interface and particle clustering effects. The model was employed to analyze the interrelationships between microstructures and mechanical properties of nanocomposites. An improved...... effective interface model which is based on Mori–Tanaka approach and includes the nanoparticle geometry and clustering effects was developed. A program code for the automatic generation of two-dimensional multiparticle unit cell models of nanocomposites and finite element meshes on the basis of “grid method...... strong influence on the mechanical properties of nanocomposite....

  13. A novel silica nanotube reinforced ionic incorporated hydroxyapatite composite coating on polypyrrole coated 316L SS for implant application.

    Science.gov (United States)

    Prem Ananth, K; Joseph Nathanael, A; Jose, Sujin P; Oh, Tae Hwan; Mangalaraj, D

    2016-02-01

    An attempt has been made to deposit a novel smart ion (Sr, Zn, Mg) substituted hydroxyapatite (I-HAp) and silica nanotube (SiNTs) composite coatings on polypyrrole (PPy) coated surgical grade 316L stainless steel (316L SS) to improve its biocompatibility and corrosion resistance. The I-HAp/SiNTS/PPy bilayer coating on 316L SS was prepared by electrophoretic deposition technique. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies were carried out. These results confirmed the significant improvement of the corrosion resistance of the 316L SS alloy by the I-HAp/SiNTs/PPy bilayer composite coating. The adhesion strength and hardness test confirmed the anticipated mechanical properties of the composite. A low contact angle value revealed the hydrophilic nature. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) was used for the leach out analysis of the samples. Added to this, the bioactivity of the composite was analyzed by observing the apatite formation in the SBF solution for 7, 14, 21 and 28days of incubation. An enhancement of in vitro osteoblast attachment and cell viability was observed, which could lead to the optimistic orthopedic and dental applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Monitoring stress changes in carbon fiber reinforced polymer composites with GHz radiation.

    Science.gov (United States)

    Schemmel, Peter; Moore, Andrew J

    2017-08-01

    We performed proof of concept experiments to demonstrate that the reflected power of GHz illumination from the surface of carbon fiber reinforced polymer (CFRP) composites is linearly related to the stress in the material. We introduce a stress coefficient to describe the change in normalized power with applied stress, analogous to the stress-optic coefficient, because the effect is attributed to changes in the refractive index of the effective medium comprising the polymer matrix and carbon fibers. Stress coefficients of -0.549±0.134/GPa and -0.154±0.024/GPa were measured for two different composite materials, both linear in the measurement range of 40 MPa and 100 Mpa, respectively. This technique opens up the possibility of non-destructive evaluation of stresses in CFRP components for quality assurance in manufacturing and in structural health monitoring of in-service aerospace and automotive parts.

  15. Liquid crystalline polymer nanocomposites reinforced with in-situ reduced graphene oxide

    Directory of Open Access Journals (Sweden)

    D. Pedrazzoli

    2015-08-01

    Full Text Available In this work liquid-crystalline polymer (LCP nanocomposites reinforced with in-situ reduced graphene oxide are investigated. Graphene oxide (GO was first synthesized by the Hummers method, and the kinetics of its thermal reduction was assessed. GO layers were then homogeneously dispersed in a thermotropic liquid crystalline polymer matrix (Vectran®, and an in-situ thermal reduction of GO into reduced graphene oxide (rGO was performed. Even at low rGO amount, the resulting nanocomposites exhibited an enhancement of both the mechanical properties and the thermal stability. Improvements of the creep stability and of the thermo-mechanical behavior were also observed upon nanofiller incorporation. Furthermore, in-situ thermal reduction of the insulating GO into the more electrically conductive rGO led to an important surface resistivity decrease in the nanofilled samples.

  16. Thermographic inspection of bond defects in Fiber Reinforced Polymer applied to masonry structures

    Science.gov (United States)

    Masini, N.; Aiello, M. A.; Capozzoli, L.; Vasanelli, E.

    2012-04-01

    Nowadays, externally bonded Fiber Reinforced Polymers (FRP) are extensively used for strengthening and repairing masonry and reinforced concrete existing structures; they have had a rapid spread in the area of rehabilitation for their many advantages over other conventional repair systems, such as lightweight, excellent corrosion and fatigue resistance, high strength, etc. FRP systems applied to masonry or concrete structures are typically installed using a wet-layup technique.The method is susceptible to cause flaws or defects in the bond between the FRP system and the substrate, which may reduce the effectiveness of the reinforcing systems and the correct transfer of load from the structure to the composite. Thus it is of primary importance to detect the presence of defects and to quantify their extension in order to eventually provide correct repair measurements. The IR thermography has been cited by the several guidelines as a good mean to qualitatively evaluate the presence of installation defects and to monitor the reinforcing system with time.The method is non-destructive and does not require contact with the composite or other means except air to detect the reinforcement. Some works in the literature have been published on this topic. Most of the researches aim at using the IR thermography technique to characterize quantitatively the defects in terms of depth, extension and type in order to have an experimental database on defect typology to evaluate the long term performances of the reinforcing system. Nevertheless, most of the works in the literature concerns with FRP applied to concrete structures without considering the case of masonry structures. In the present research artificial bond defects between FRP and the masonry substrate have been reproduced in laboratory and the IR multi temporal thermography technique has been used to detect them. Thermographic analysis has been carried out on two wall samples having limited dimensions (100 x 70 cm) both

  17. Experimental Study of Concrete-filled Carbon Fiber Reinforced Polymer Tube with Internal Reinforcement under Axially Loading

    Directory of Open Access Journals (Sweden)

    Wenbin SUN

    2014-12-01

    Full Text Available Comparing with the circular concrete columns confined with fiber reinforced polymer (FRP wrap or tube, the rectilinear confined columns were reported much less. Due to the non-uniform distribution of confining pressure in the rectilinear confined columns, the FRP confinement effectiveness was significant reduced. This paper presents findings of an experimental program where nine prefabricated rectangular cross-section CFRP tubes with CFRP integrated crossties filled concrete to form concrete-filled FRP tube (CFFT short columns and three plain concrete control specimens were tested. All specimens were axially loaded until failure. The rest results showed that the stress-strain curves of CFFTs consisted of two distinct branches, an ascending branch before the concrete peak stress was reaches and a second branch that terminated when the tube ruptured, and that the CFFTs with integrated crossties experienced most uniform confinement pressure distribution. Test research also found that the stress-strain curves of CFFTs indicated an increase in ductility. These demonstrate that this confinement system can produce higher lateral confinement stiffness. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6035

  18. Durability of carbon fiber reinforced shape memory polymer composites in space

    Science.gov (United States)

    Jang, Joon Hyeok; Hong, Seok Bin; Ahn, Yong San; Kim, Jin-Gyun; Nam, Yong-Youn; Lee, Geun Ho; Yu, Woong-Ryeol

    2016-04-01

    Shape memory polymer (SMP) is one of smart polymers which exhibit shape memory effect upon external stimuli. Recently, shape memory polymer composites (SMPCs) have been considered for space structure instead of shape memory alloys due to their deformability, lightweight and large recovery ratio, requiring characterization of their mechanical properties against harsh space environment and further prediction of the durability of SMPCs in space. As such, the durability of carbon fiber reinforced shape memory polymer composites (CF-SMPCs) was investigated using accelerated testing method based on short-term testing of CF-SMPCs in harsh condition. CF-SMPCs were prepared using woven carbon fabrics and a thermoset SMP via vacuum assisted resin transfer molding process. Bending tests with constant strain rate of CF-SMPCs were conducted using universal tensile machine (UTM) and Storage modulus test were conducted using dynamic mechanical thermal analysis (DMTA). Using the results, a master curve based on time-temperature superposition principle was then constructed, through which the mechanical properties of CF-SMPCs at harsh temperature were predicted. CF-SMPCs would be exposed to simulated space environments under ultra-violet radiations at various temperatures. The mechanical properties including flexural and tensile strength and shape memory properties of SMPCs would be measured using UTM before and after such exposures for comparison. Finally, the durability of SMPCs in space would be assessed by developing a degradation model of SMPC.

  19. The Impact Resistance of Fiber-Reinforced Polymer Composites: A Review

    Directory of Open Access Journals (Sweden)

    Mahmood Mehrdad Shokrieh

    2012-12-01

    Full Text Available Fiber reinforced composites are widely used instead of traditional materials in various technological applications. Therefore, by considering the extensive applications of these materials, a proper knowledge of their impact behavior (from low- to high-velocity as well as their static behavior is necessary. In order to study the effects of strain rates on the behavior of these materials, special testing machines are needed. Most of the research efforts in this feld are focused on application of real loading and gripping boundary conditions on the testing specimens. In this paper, a detailed review of different types of impact testing techniques and the strain rate dependence of mechanical and strength properties of polymer composite materials  are presented. In this respect, an attempt is made to present and summarize the methods of impact tests and the strain rate effects on the tensile, compressive, shear and bending properties of the fber-reinforced polymer composite materials. Moreover, a classifcation of the state-of-the-art of the testing techniques to characterize composite material properties in a wide range of strain rates are also given.

  20. Fiber reinforced shape-memory polymer composite and its application in a deployable hinge

    Science.gov (United States)

    Lan, Xin; Liu, Yanju; Lv, Haibao; Wang, Xiaohua; Leng, Jinsong; Du, Shanyi

    2009-02-01

    This paper investigates the shape recovery behavior of thermoset styrene-based shape-memory polymer composite (SMPC) reinforced by carbon fiber fabrics, and demonstrates the feasibility of using an SMPC hinge as a deployable structure. The major advantages of shape-memory polymers (SMPs) are their extremely high recovery strain, low density and low cost. However, relatively low modulus and low strength are their intrinsic drawbacks. A fiber reinforced SMPC which may overcome the above-mentioned disadvantages is studied here. The investigation was conducted by three types of test, namely dynamic mechanical analysis (DMA), a shape recovery test, and optical microscopic observations of the deformation mechanism for an SMPC specimen. Results reveal that the SMPC exhibits a higher storage modulus than that of a pure SMP. At/above Tg, the shape recovery ratio of the SMPC upon bending is above 90%. The shape recovery properties of the SMPC become relatively stable after some packaging/deployment cycles. Additionally, fiber microbuckling is the primary mechanism for obtaining a large strain in the bending of the SMPC. Moreover, an SMPC hinge has been fabricated, and a prototype of a solar array actuated by the SMPC hinge has been successfully deployed.

  1. Multifunctional fiber reinforced polymer composites using carbon and boron nitride nanotubes

    Science.gov (United States)

    Ashrafi, Behnam; Jakubinek, Michael B.; Martinez-Rubi, Yadienka; Rahmat, Meysam; Djokic, Drazen; Laqua, Kurtis; Park, Daesun; Kim, Keun-Su; Simard, Benoit; Yousefpour, Ali

    2017-12-01

    Recent progress in nanotechnology has made several nano-based materials available with the potential to address limitations of conventional fiber reinforced polymer composites, particularly in reference to multifunctional structures. Carbon nanotubes (CNTs) are the most prevalent case and offer amazing properties at the individual nanotube level. There are already a few high-profile examples of the use of CNTs in space structures to provide added electrical conductivity for static dissipation and electromagnetic shielding. Boron nitride nanotubes (BNNTs), which are structurally analogous to CNTs, also present a range of attractive properties. Like the more widely explored CNTs, individual BNNTs display remarkable mechanical properties and high thermal conductivity but with contrasting functional attributes including substantially higher thermal stability, high electrical insulation, polarizability, high neutron absorption and transparency to visible light. This presents the potential of employing either or both BNNTs and CNTs to achieve a range of lightweight, functional composites for space structures. Here we present the case for application of BNNTs, in addition to CNTs, in space structures and describe recent advances in BNNT production at the National Research Council Canada (NRC) that have, for the first time, provided sufficiently large quantities to enable commercialization of high-quality BNNTs and accelerate development of chemistry, composites and applications based on BNNTs. Early demonstrations showing the fabrication and limited structural testing of polymer matrix composites, including glass fiber-reinforced composite panels containing BNNTs will be discussed.

  2. Characterizing the self-sensing performance of carbon nanotube-enhanced fiber-reinforced polymers

    Science.gov (United States)

    Loyola, Bryan R.; La Saponara, Valeria; Loh, Kenneth J.

    2010-04-01

    The increased usage of fiber-reinforced polymers (FRP) in recent decades has created a need to monitor the unique response of these materials to impact and fatigue damage. As most traditional nondestructive evaluation methods are illsuited to detecting damage in FRPs, new methods must be created without compromising the high strength-to-weight aspects of FRPs. This paper describes the characterization of carbon nanotube-polyelectrolyte thin films applied to glass fiber substrates as a means for in situ strain sensing in glass fiber-reinforced polymers (GFRP). The layer-by-layer deposition process employed is capable of depositing individual and small bundles of carbon nanotubes within a polyelectrolyte matrix and directly onto glass fiber matrices. Upon film fabrication, the nanocomposite-coated GFRP specimens are mounted in a load frame for characterizing their electromechanical performance. This preliminary results obtained from this study has shown that these thin films exhibit bilinear piezoresistivity. Time- and frequency-domain techniques are utilized to characterize the nanocomposite strain sensing response. An equivalent circuit is also derived from electrical impedance spectroscopic analysis of thin film specimens.

  3. Full Scale RC Beam-Column Joints Strengthened with Steel Reinforced Polymer Systems

    Science.gov (United States)

    De Vita, Alessandro; Napoli, Annalisa; Realfonzo, Roberto

    2017-07-01

    This paper presents the results of an experimental campaign performed at the Laboratory of Materials and Structural Testing of the University of Salerno (Italy) in order to investigate the seismic performance of RC beam-column joints strengthened with Steel Reinforced Polymer (SRP) systems. With the aim to represent typical façade frames’ beam-column subassemblies found in existing RC buildings, specimens were provided with two short beam stubs orthogonal to the main beam and were designed with inadequate seismic details. Five members were strengthened by using two different SRP layouts while the remaining ones were used as benchmarks. Once damaged, two specimens were also repaired, retrofitted with SRP and subjected to cyclic test again. The results of cyclic tests performed on SRP strengthened joints are examined through a comparison with the outcomes of the previous experimental program including companion specimens not provided with transverse beam stubs and strengthened by Carbon Fiber Reinforced Polymer (CFRP) systems. In particular, both qualitative and quantitative considerations about the influence of the confining effect provided by the secondary beams on the joint response, the suitability of all the adopted strengthening solutions (SRP/CFRP systems), the performances and the failure modes experienced in the several cases studied are provided.

  4. Effect of fiber reinforcement on thermo-oxidative stability and mechanical properties of polymer matrix composites

    Science.gov (United States)

    Bowles, K. J.

    1992-01-01

    A number of studies have investigated the thermooxidative behavior of polymer matrix composites. Two significant observations have been made from these research efforts: (1) fiber reinforcement has a significant effect on composite thermal stability; and (2) geometric effects must be considered when evaluating thermal aging data. The polyimide PMR-15 was the matrix material used in these studies. The control composite material was reinforced with Celion 6000 graphite fiber. T-4OR graphite fibers, along with some very stable ceramic fibers were selected as reinforcing fibers because of their high thermal stability. The ceramic fibers were Nicalon (silicon carbide) and Nextel 312 (alumina-silica-boron oxide). The mechanical properties of the two graphite fiber composites were significantly different, probably owing to variations in interfacial bonding between the fibers and the polyimide matrix. Three oxidation mechanisms were observed: (1) the preferential oxidation of the Celion 6000 fiber ends at cut surfaces, leaving a surface of matrix material with holes where the fiber ends were originally situated; (2) preferential oxidation of the composite matrix; and (3) interfacial degradation by oxidation. The latter two mechanisms were also observed on fiber end cut surfaces. The fiber and interface attacks appeared to initiate interfiber cracking along these surfaces.

  5. Compressive Strength of Post Fire Exposed Concrete Column Wrapped with Fiber Reinforced Polymer

    Directory of Open Access Journals (Sweden)

    Dwi Agus Setiawan Wardaya

    2017-09-01

    Full Text Available In this study, behaviour of reinforced concrete columns strengthened using fiber reinforced polymer (FRP; glass fiber and carbon fiber after fire exposure are discussed. After being exposed to fire as high as 720oC for 180 minutes, the specimens showed concrete and  reinforcement strength degradation, even though there was no carbonation. It was found that specimens wrapped by carbon fiber showed better compressive strength but less ductility compared to specimens wrapped by glass fiber. It was also found that the low initial compressive strength did not decrease FRP confinement effectiveness. Increase of wrapped concrete com­pressive strength was evident despite the low initial strength (<17 MPa. Strength esti­mation using ACI 440.2R-08 formula, which is originally for wrapped plain concrete without fire heat exposure, underestimated the compressive strength. In the proposed formula, the initial compressive strength (f’co should be adjusted by considering the modulus elasticity and strain limitation to have more precise estimation.

  6. Thermal and Mechanical Behavior of Hybrid Polymer Nanocomposite Reinforced with Graphene Nanoplatelets

    Directory of Open Access Journals (Sweden)

    Minh-Tai Le

    2015-08-01

    Full Text Available In the present investigation, we successfully fabricate a hybrid polymer nanocomposite containing epoxy/polyester blend resin and graphene nanoplatelets (GNPs by a novel technique. A high intensity ultrasonicator is used to obtain a homogeneous mixture of epoxy/polyester resin and graphene nanoplatelets. This mixture is then mixed with a hardener using a high-speed mechanical stirrer. The trapped air and reaction volatiles are removed from the mixture using high vacuum. The hot press casting method is used to make the nanocomposite specimens. Tensile tests, dynamic mechanical analysis (DMA and thermogravimetric analysis (TGA are performed on neat, 0.2 wt %, 0.5 wt %, 1 wt %, 1.5 wt % and 2 wt % GNP-reinforced epoxy/polyester blend resin to investigate the reinforcement effect on the thermal and mechanical properties of the nanocomposites. The results of this research indicate that the tensile strength of the novel nanocomposite material increases to 86.8% with the addition of a ratio of graphene nanoplatelets as low as 0.2 wt %. DMA results indicate that the 1 wt % GNP-reinforced epoxy/polyester nanocomposite possesses the highest storage modulus and glass transition temperature (Tg, as compared to neat epoxy/polyester or the other nanocomposite specimens. In addition, TGA results verify thethermal stability of the experimental specimens, regardless of the weight percentage of GNPs.

  7. Visual classification of braided and woven fiber bundles in X-ray computed tomography scanned carbon fiber reinforced polymer specimens

    OpenAIRE

    Weissenböck, Johannes; Bhattacharya, Arindam; Plank, Bernhard; Heinzl, Christoph; Kastner, Johann

    2016-01-01

    In recent years, advanced composite materials such as carbon fiber reinforced polymers (CFRP) are used in many fields of application (e.g., automotive, aeronautic and leisure industry). These materials are characterized by their high stiffness and strength, while having low weight. Especially, woven carbon fiber reinforced materials have outstanding mechanical properties due to their fabric structure. To analyze and develop the fabrics, it is important to understand the course of the individu...

  8. PERBAIKAN KEKUATAN DAN DAKTILITAS KOLOM BETON BERTULANG YANG MENDAPAT BEBAN GEMPA MENGGUNAKAN GLASS FIBER REINFORCED POLYMER

    Directory of Open Access Journals (Sweden)

    Parmo Parmo

    2014-05-01

    Full Text Available Repairing the Strength and Ductility of Reinforced Concrete Column That Got Earthquake using Gla­ss Fiber Reinforced Polymer. This study aims to identify the additional strength and ductility of reinforced concrete columns af­ter being re­­­­tro­fitted using glass fiber reinforced polymer (GFRP and got the brunt of the earth­quake. This study uses two objects tested columns, which are being tested for three times. Each column size is 350 x 350 x 1100 mm with f'c = 20.34 MPa and fy = 549.94 MPa. The tes­t­ing is performed by giving a constant axial load of 748 kN and cyclic lateral load using con­trol displacement method in order to simulate the brunt of earth­quake. The results show an in­crea­se in lateral capacity of co­lumn by 43.96%. Re­tro­­fitting the column with GFRP has a duc­tile property, which is shown by the increase of the displacement ductility by 129.14% and curvature ductility by 118.27%.   Penelitian ini ber­tujuan untuk mengetahui penambahan kekuatan dan dak­ti­li­­­­tas kolom beton bertulang se­telah diretrofit menggunakan glass fiber reinforced po­ly­­­mer (GFRP dan mendapat be­ban gempa. Penelitian ini menggunakan benda ­uji dua buah kolom dengan tiga kali pengujian. Masing-masing ukuran kolom 350 x 350 x 1100 mm dengan f’c = 20,34 MPa dan fy = 549,94 MPa. Pengujian dilakukan de­ngan memberikan beban ak­sial konstan 748 kN dan beban lateral siklik yang meng­gu­nakan metode di­splacemet con­trol untuk mensimulasikan beban gempa. Hasil pe­ne­­­litian menunjukkan pe­ningkatan kapasitas lateral pada kolom sebesar 43,96%. Retrofit kolom dengan GFRP bersifat dak­tail yang ditunjukkan dengan meningkatnya daktilitas per­pindahan sebesar 129,14% dan dak­­­tilitas kurvatur se­besar 118,27%.

  9. On complexities of impact simulation of fiber reinforced polymer composites: a simplified modeling framework.

    Science.gov (United States)

    Alemi-Ardakani, M; Milani, A S; Yannacopoulos, S

    2014-01-01

    Impact modeling of fiber reinforced polymer composites is a complex and challenging task, in particular for practitioners with less experience in advanced coding and user-defined subroutines. Different numerical algorithms have been developed over the past decades for impact modeling of composites, yet a considerable gap often exists between predicted and experimental observations. In this paper, after a review of reported sources of complexities in impact modeling of fiber reinforced polymer composites, two simplified approaches are presented for fast simulation of out-of-plane impact response of these materials considering four main effects: (a) strain rate dependency of the mechanical properties, (b) difference between tensile and flexural bending responses, (c) delamination, and (d) the geometry of fixture (clamping conditions). In the first approach, it is shown that by applying correction factors to the quasistatic material properties, which are often readily available from material datasheets, the role of these four sources in modeling impact response of a given composite may be accounted for. As a result a rough estimation of the dynamic force response of the composite can be attained. To show the application of the approach, a twill woven polypropylene/glass reinforced thermoplastic composite laminate has been tested under 200 J impact energy and was modeled in Abaqus/Explicit via the built-in Hashin damage criteria. X-ray microtomography was used to investigate the presence of delamination inside the impacted sample. Finally, as a second and much simpler modeling approach it is shown that applying only a single correction factor over all material properties at once can still yield a reasonable prediction. Both advantages and limitations of the simplified modeling framework are addressed in the performed case study.

  10. On Complexities of Impact Simulation of Fiber Reinforced Polymer Composites: A Simplified Modeling Framework

    Science.gov (United States)

    Alemi-Ardakani, M.; Milani, A. S.; Yannacopoulos, S.

    2014-01-01

    Impact modeling of fiber reinforced polymer composites is a complex and challenging task, in particular for practitioners with less experience in advanced coding and user-defined subroutines. Different numerical algorithms have been developed over the past decades for impact modeling of composites, yet a considerable gap often exists between predicted and experimental observations. In this paper, after a review of reported sources of complexities in impact modeling of fiber reinforced polymer composites, two simplified approaches are presented for fast simulation of out-of-plane impact response of these materials considering four main effects: (a) strain rate dependency of the mechanical properties, (b) difference between tensile and flexural bending responses, (c) delamination, and (d) the geometry of fixture (clamping conditions). In the first approach, it is shown that by applying correction factors to the quasistatic material properties, which are often readily available from material datasheets, the role of these four sources in modeling impact response of a given composite may be accounted for. As a result a rough estimation of the dynamic force response of the composite can be attained. To show the application of the approach, a twill woven polypropylene/glass reinforced thermoplastic composite laminate has been tested under 200 J impact energy and was modeled in Abaqus/Explicit via the built-in Hashin damage criteria. X-ray microtomography was used to investigate the presence of delamination inside the impacted sample. Finally, as a second and much simpler modeling approach it is shown that applying only a single correction factor over all material properties at once can still yield a reasonable prediction. Both advantages and limitations of the simplified modeling framework are addressed in the performed case study. PMID:25431787

  11. Corrosion of steel members strengthenened with carbon fiber reinforced polymer sheets

    Science.gov (United States)

    Bumadian, Ibrahim

    Due to many years of service at several cases of exposure at various environments there are many of steel bridges which are in need of rehabilitation. The infrastructure needs upgrading, repair or maintenance, and also strengthening, but by using an alternative as retrofits methods. The alternative retrofit method, which used fiber reinforced polymer (FRP) composite materials which their strength materials comes largely from the fiber such as carbon, glass, and aramid fiber. Of the most important materials used in the rehabilitation of infrastructure is a composite material newly developed in bonded externally carbon fiber and polymer (CFRP) sheets, which has achieved remarkable success in the rehabilitation and upgrading of structural members. This technique has many disadvantages one of them is galvanic corrosion. This study presents the effect of galvanic corrosion on the interfacial strength between carbon fiber reinforced polymer (CFRP) sheets and a steel substrate. A total of 35 double-lap joint specimens and 19 beams specimens are prepared and exposed to an aggressive service environment in conjunction with an electrical potential method accelerating corrosion damage. Six test categories are planned at a typical exposure interval of 12 hours, including five specimens per category for double-lap joint specimens. And six test categories are planned at a typical exposure interval of 12 hours, including three specimens per category for Beam section specimens. In addition one beam section specimen is control. The degree of corrosion is measured. Fourier transform infrared (FTIR) reflectance spectroscopy has been used to monitor and confirm the proposed corrosion mechanisms on the surface of CFRP. In this study we are using FTIR-spectroscopic measurement systems in the mid infrared (MIR) wavelength region (4000 - 400) cm-1 to monitor characteristic spectral features. Upon completion of corrosion processes, all specimens are monotonically loaded until failure

  12. Numerical Simulation of Thermal Performance of Glass-Fibre-Reinforced Polymer

    Science.gov (United States)

    Zhao, Yuchao; Jiang, Xu; Zhang, Qilin; Wang, Qi

    2017-10-01

    Glass-Fibre-Reinforced Polymer (GFRP), as a developing construction material, has a rapidly increasing application in civil engineering especially bridge engineering area these years, mainly used as decorating materials and reinforcing bars for now. Compared with traditional construction material, these kinds of composite material have obvious advantages such as high strength, low density, resistance to corrosion and ease of processing. There are different processing methods to form members, such as pultrusion and resin transfer moulding (RTM) methods, which process into desired shape directly through raw material; meanwhile, GFRP, as a polymer composite, possesses several particular physical and mechanical properties, and the thermal property is one of them. The matrix material, polymer, performs special after heated and endue these composite material a potential hot processing property, but also a poor fire resistance. This paper focuses on thermal performance of GFRP as panels and corresponding researches are conducted. First, dynamic thermomechanical analysis (DMA) experiment is conducted to obtain the glass transition temperature (Tg) of the object GFRP, and the curve of bending elastic modulus with temperature is calculated according to the experimental data. Then compute and estimate the values of other various thermal parameters through DMA experiment and other literatures, and conduct numerical simulation under two condition respectively: (1) the heat transfer process of GFRP panel in which the panel would be heated directly on the surface above Tg, and the hot processing under this temperature field; (2) physical and mechanical performance of GFRP panel under fire condition. Condition (1) is mainly used to guide the development of high temperature processing equipment, and condition (2) indicates that GFRP’s performance under fire is unsatisfactory, measures must be taken when being adopted. Since composite materials’ properties differ from each other

  13. Electrochemical performance of an air-breathing direct methanol fuel cell using poly(vinyl alcohol)/hydroxyapatite composite polymer membrane

    Science.gov (United States)

    Yang, Chun-Chen; Chiu, Shwu-Jer; Lin, Che-Tseng

    A novel composite polymer membrane based on poly(vinyl alcohol)/hydroxyapatite (PVA/HAP) was successfully prepared by a solution casting method. The characteristic properties of the PVA/HAP composite polymer membranes were examined by thermal gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), micro-Raman spectroscopy and AC impedance method. An air-breathing DMFC, comprised of an air cathode electrode with MnO 2/BP2000 carbon inks on Ni-foam, an anode electrode with PtRu black on Ti-mesh, and the PVA/HAP composite polymer membrane, was assembled and studied. It was found that this alkaline DMFC showed an improved electrochemical performance at ambient temperature and pressure; the maximum peak power density of an air-breathing DMFC in 8 M KOH + 2 M CH 3OH solution is about 11.48 mW cm -2. From the application point of view, these composite polymer membranes show a high potential for the DMFC applications.

  14. Synthesis and character investigation of new collagen Hydrolysate/polyvinyl alcohol/hydroxyapatite Polymer-Nano-Porous Membranes: I. Experimental design optimization in thermal and structural properties.

    Science.gov (United States)

    Imanieh, Hossein; Aghahosseini, Hamideh

    2013-12-01

    Development of bioorganic-inorganic composites has drawn eyes to extensive attention in biomedical fields and tissue engineering. So many attempts to prepare hydroxyapatite (HA), in conjunction with various binders including polyvinyl alcohol (PVA), and collagen has performed for late 20 years. We applied a method based on the phase separation for making of polymer porous membranes. This procedure is induced through the addition of a small quantity of water (polymer-rich phase) to a solution with HA precursors (polymer-poor phase). Thermal and structural composite properties of collagen Hydrolysate (CH)-PVA/HA Polymer-Nano-Porous Membranes were analyzed by Design of experiment that was undertaken using D-optimal approach, to select the optimal combination of nano composites precursor. The resulted composite characters were investigated by Fourier transform infrared, scanning electron microscopy (SEM) and thermal gravimetric analysis. Based on the SEM images, this new method could be clearly concluded to porous CH-PVA/HA hybrid materials. Finally the hemocompatibility of nanocomposite membranes were evaluated by the hemolysis study.

  15. Electrical and Mechanical Performance of Carbon Fiber-Reinforced Polymer Used as the Impressed Current Anode Material.

    Science.gov (United States)

    Zhu, Ji-Hua; Zhu, Miaochang; Han, Ningxu; Liu, Wei; Xing, Feng

    2014-07-24

    An investigation was performed by using carbon fiber-reinforced polymer (CFRP) as the anode material in the impressed current cathodic protection (ICCP) system of steel reinforced concrete structures. The service life and performance of CFRP were investigated in simulated ICCP systems with various configurations. Constant current densities were maintained during the tests. No significant degradation in electrical and mechanical properties was found for CFRP subjected to anodic polarization with the selected applied current densities. The service life of the CFRP-based ICCP system was discussed based on the practical reinforced concrete structure layout.

  16. Electrical and Mechanical Performance of Carbon Fiber-Reinforced Polymer Used as the Impressed Current Anode Material

    Directory of Open Access Journals (Sweden)

    Ji-Hua Zhu

    2014-07-01

    Full Text Available An investigation was performed by using carbon fiber-reinforced polymer (CFRP as the anode material in the impressed current cathodic protection (ICCP system of steel reinforced concrete structures. The service life and performance of CFRP were investigated in simulated ICCP systems with various configurations. Constant current densities were maintained during the tests. No significant degradation in electrical and mechanical properties was found for CFRP subjected to anodic polarization with the selected applied current densities. The service life of the CFRP-based ICCP system was discussed based on the practical reinforced concrete structure layout.

  17. Ion pair reinforced semi-interpenetrating polymer network for direct methanol fuel cell applications.

    Science.gov (United States)

    Fang, Chunliu; Julius, David; Tay, Siok Wei; Hong, Liang; Lee, Jim Yang

    2012-06-07

    This paper describes the synthesis of ion-pair-reinforced semi-interpenetrating polymer networks (SIPNs) as proton exchange membranes (PEMs) for the direct methanol fuel cells (DMFCs). Specifically, sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO), a linear polymer proton source, was immobilized in a brominated PPO (BPPO) network covalently cross-linked by ethylenediamine (EDA). The immobilization of SPPO in the SIPN network was accomplished not only by the usual means of mechanical interlocking but also by ion pair formation between the sulfonic acid groups of SPPO and the amine moieties formed during the cross-linking reaction of BPPO with EDA. Through the ion pair interactions, the immobilization of SPPO polymer in the BPPO network was made more effective, resulting in a greater uniformity of sulfonic acid cluster distribution in the membrane. The hydrophilic amine-containing cross-links also compensated for some of the decrease in proton conductivity caused by ion pair formation. The SIPN membranes prepared as such showed good proton conductivity, low methanol permeability, good mechanical properties, and dimensional stability. Consequently, the PPO based SIPN membranes were able to deliver a higher maximum power density than Nafion, demonstrating the potential of the SIPN structure for PEM designs.

  18. Experimental Investigation on the Durability of Glass Fiber-Reinforced Polymer Composites Containing Nanocomposite

    Directory of Open Access Journals (Sweden)

    Weiwen Li

    2013-01-01

    Full Text Available Nanoclay layers incorporated into polymer/clay nanocomposites can inhibit the harmful penetration of water and chemicals into the material, and thus the durability of glass fiber-reinforced polymer (GFRP composites should be enhanced by using polymer/clay nanocomposite as the matrix material. In this study, 1.5 wt% vinyl ester (VE/organoclay and 2 wt% epoxy (EP/organoclay nanocomposites were prepared by an in situ polymerization method. The dispersion states of clay in the nanocomposites were studied by performing XRD analysis. GFRP composites were then fabricated with the prepared 1.5 wt% VE/clay and 2.0 wt% EP/clay nanocomposites to investigate the effects of a nanocomposite matrix on the durability of GFRP composites. The durability of the two kinds of GFRP composites was characterized by monitoring tensile properties following degradation of GFRP specimens aged in water and alkaline solution at 60°C, and SEM was employed to study fracture behaviors of aged GFRP composites under tension. The results show that tensile properties of the two types of GFRP composites with and without clay degrade significantly with aging time. However, the GFRP composites with nanoclay show a lower degradation rate compared with those without nanoclay, supporting the aforementioned hypothesis. And the modification of EP/GFRP enhanced the durability more effectively.

  19. Elastomeric Polymers for Retrofitting of Reinforced Concrete Structures against the Explosive Effects of Blast

    Directory of Open Access Journals (Sweden)

    S. N. Raman

    2012-01-01

    Full Text Available The main distinction of blast load from other types of dynamic loadings is its impulsive nature, where the loads usually act for a very short duration but transmit very high impulsive pressures. This paper presents an overview of the present retrofitting techniques in use to enhance the capacity of structural elements to withstand the effects of blast loads, and introduces an alternative retrofitting approach by utilizing polymer coatings. The authors have demonstrated the positive effects of this approach by conducting a numerical investigation on the behavior of an unretrofitted reinforced concrete panel subjected to the blast load from a 2 kg charge at 1.6 m stand-off distance, and subsequently comparing its performance with several polymer coated panels. The analysis was performed by using an explicit nonlinear finite element (FE code. The results demonstrate the contributions of this technique in terms of panel displacement control and energy dissipation. Considering that the polymer coating can also act as a protective layer in improving the durability of structural materials, this technique can also be optimized favorably to enhance the overall sustainability of structures.

  20. Structural, compositional, mechanical characterization and biological assessment of bovine-derived hydroxyapatite coatings reinforced with MgF2 or MgO for implants functionalization.

    Science.gov (United States)

    Mihailescu, Natalia; Stan, G E; Duta, L; Chifiriuc, Mariana Carmen; Bleotu, Coralia; Sopronyi, M; Luculescu, C; Oktar, F N; Mihailescu, I N

    2016-02-01

    Hydroxyapatite (HA) is a consecrated biomaterial for bone reconstruction. In the form of thin films deposited by pulsed laser technologies, it can be used to cover metallic implants aiming to increase biocompatibility and osseointegration rate. HA of animal origin (bovine, BHA) reinforced with MgF2 (2wt.%) or MgO (5wt.%) were used for deposition of thin coatings with improved adherence, biocompatibility and antimicrobial activity. For pulsed laser deposition experiments, a KrF* (λ=248nm, τFWHM≤25ns) excimer laser source was used. The deposited structures were characterized from a physical-chemical point of view by X-Ray Diffraction, Fourier Transform Infra-Red Spectroscopy, Scanning Electron Microscopy in top- and cross-view modes, Energy Dispersive X-Ray Spectroscopy and Pull-out adherence tests. The microbiological assay using the HEp-2 cell line revealed that all target materials and deposited thin films are non-cytotoxic. We conducted tests on three strains isolated from patients with dental implants failure, i.e. Microccocus sp., Enterobacter sp. and Candida albicans sp. The most significant anti-biofilm effect against Microcococcus sp. strain, at 72h, was obtained in the presence of BHA:MgO thin films. For Enterobacter sp. strain a superior antimicrobial activity at 72h was noticed, in respect with simple BHA or Ti control. The enhanced antimicrobial performances, correlated with good cytocompatibility and mechanical properties recommend these biomaterials as an alternative to synthetic HA for the fabrication of reliable implant coatings for dentistry and other applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Polydopamine-Templated Hydroxyapatite Reinforced Polycaprolactone Composite Nanofibers with Enhanced Cytocompatibility and Osteogenesis for Bone Tissue Engineering.

    Science.gov (United States)

    Gao, Xiang; Song, Jinlin; Ji, Ping; Zhang, Xiaohong; Li, Xiaoman; Xu, Xiao; Wang, Mengke; Zhang, Siqi; Deng, Yi; Deng, Feng; Wei, Shicheng

    2016-02-10

    Nanohydroxyapatite (HA) synthesized by biomimetic strategy is a promising nanomaterial as bone substitute due to its physicochemical features similar to those of natural nanocrystal in bone tissue. Inspired by mussel adhesive chemistry, a novel nano-HA was synthesized in our work by employing polydopamine (pDA) as template under weak alkaline condition. Subsequently, the as-prepared pDA-templated HA (tHA) was introduced into polycaprolactone (PCL) matrix via coelectrospinning, and a bioactive tHA/PCL composite nanofiber scaffold was developed targeted at bone regeneration application. Our research showed that tHA reinforced PCL composite nanofibers exhibited favorable cytocompatibility at given concentration of tHA (0-10 w.t%). Compared to pure PCL and traditional nano-HA enriched PCL (HA/PCL) composite nanofibers, enhanced cell adhesion, spreading and proliferation of human mesenchymal stem cells (hMSCs) were observed on tHA/PCL composite nanofibers on account of the contribution of pDA present in tHA. More importantly, tHA nanoparticles exposed on the surface of composite nanofibers could further promote osteogenesis of hMSCs in vitro even in the absence of osteogenesis soluble inducing factors when compared to traditional HA/PCL scaffolds, which was supported by in vivo test as well according to the histological analysis. Overall, our study demonstrated that the developed tHA/PCL composite nanofibers with enhanced cytocompatibility and osteogenic capacity hold great potential as scaffolds for bone tissue engineering.

  2. Automatic design of the flexural strengthening of reinforced concrete beams using fiber reinforced polymers (FRP - doi: 10.4025/actascitechnol.v34i2.8318

    Directory of Open Access Journals (Sweden)

    Rafael Alves de Souza

    2012-03-01

    Full Text Available Changing the functions of a building, the presence of some design or construction errors, the incidence of seismic actions and even the updating of design codes may demand the strengthening of certain structures. In the specific case of reinforced concrete structures it is desirable the application of a technique of strengthening which is fast, economic and efficient, in order to provide advantages when an intervention is necessary. The technique of strengthening chosen must provide less disorder as possible as well as the guaranty of safety. Taking into account this scenery, fiber reinforced polymers have been working as a very attractive alternative for rehabilitating in-service structures. In that way, the present study aims at presenting the main properties of this new material as well as the design routines for flexural strengthening of reinforced concrete beams. Finally, a package-software developed into the MATLAB platform is presented, intending to generate a simple tool for the automatic design using fiber reinforced polymers.

  3. Effect of Al2O3 Reinforcement and Al2O3–13 wt% TiO2 Bond Coat on Plasma Sprayed Hydroxyapatite Coating

    OpenAIRE

    Manoj Mittal; Nath, S K; Satya Prakash

    2012-01-01

    In present work an attempt has been made to enhance mechanical properties of plasma sprayed hydroxyapatite coating by addition of 10 wt% aluminum oxide. A bond coat of Al2O3-13TiO2 has been  applied to improve strength of hydroxyapatite composite coating. Mechanical properties of coatings with addition of alumina and with incorporation of bond coat have been investigated in accordance with the ASTM C 633-79. Results indicate that the tensile bond strength of hydroxyapatite coating increased b...

  4. Water sorption and dimensional changes of denture base polymer reinforced with glass fibers in continuous unidirectional and woven form.

    Science.gov (United States)

    Cal, N E; Hersek, N; Sahin, E

    2000-01-01

    The aim of this study was to determine the dimensional accuracy and water sorption of a denture base polymer that was reinforced with glass fibers in continuous unidirectional and woven form in different weight fractions. Ten rhombic brass plates were prepared with reference points, and 70 heat-cured denture base polymer specimens were produced using these brass models. Ten of 70 were used for controls, and 60 were reinforced with glass fibers in continuous parallel and woven form. The dimensional changes of polymer and fiber-reinforced composite specimens after processing, drying for 4 days at 37 degrees C, and storage in 37 degrees C water for 90 days were calculated by the change of the distance vector. The measurements were made between the reference points on the specimens and were compared with those on the brass model at 4 different stages. The water sorption calculations were made at 10 different time intervals on 70 specimens, which were immersed in a 37 degrees C distilled water bath and weighed. The polymerization shrinkage and water sorption of denture base polymers is lower when the specimens are reinforced with glass fibers in continuous unidirectional and woven form. The highest fiber content showed the smallest dimensional change (0.069 mm, or 0.25%), and the unreinforced group showed the largest change (0.139 mm, or 0.54%). Water sorption occurred mainly during the first 14 days. As the fiber content increases, the dimensional change and water sorption decrease.

  5. Fiber reinforced polymer (FRP) composite piles used on pier rehabilitation, Little Diamond Island, Casco Bay, Portland, Maine.

    Science.gov (United States)

    2012-10-01

    Fiber reinforced polymer (FRP) composite piles were used on a pier rehabilitation project at : Little Diamond Island in Casco Bay near Portland Maine. The project was the replacement : of an aging wooden pier at the ferry berthing terminal. The FRP p...

  6. Cellulose Nanocrystals vs. Cellulose Nanofibrils: A Comparative study on Their Microstructures and Effects as Polymer Reinforcing Agents

    Science.gov (United States)

    Xuezhu Xu; Fei Liu; Long Jiang; J.Y. Zhu; Darrin Haagenson; Dennis P. Wiesenborn

    2013-01-01

    Both cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) are nanoscale cellulose fibers that have shown reinforcing effects in polymer nanocomposites. CNCs and CNFs are different in shape, size and composition. This study systematically compared their morphologies, crystalline structure, dispersion properties in polyethylene oxide (PEO) matrix, interactions...

  7. Development of advanced grid stiffened (AGS) fiber reinforced polymer (FRP) tube-encased concrete columns : [technical summary].

    Science.gov (United States)

    2013-03-01

    In recent years, the use of fi ber reinforced polymer (FRP) tube-encased concrete columns for new construction and rebuilding : of engineering structures has increased. The purpose in FRP tube-encased concrete columns is to replace the steel rebar by...

  8. Nondestructive evaluation of defects in carbon fiber reinforced polymer (CFRP) composites

    Science.gov (United States)

    Ngo, Andrew C. Y.; Goh, Henry K. H.; Lin, Karen K.; Liew, W. H.

    2017-04-01

    Carbon fiber reinforced polymer (CFRP) composites are increasingly used in aerospace applications due to its superior mechanical properties and reduced weight. Adhesive bonding is commonly used to join the composite parts since it is capable of joining incompatible or dissimilar components. However, insufficient adhesive or contamination in the adhesive bonds might occur and pose as threats to the integrity of the plane during service. It is thus important to look for suitable nondestructive testing (NDT) techniques to detect and characterize the sub-surface defects within the CFRP composites. Some of the common NDT techniques include ultrasonic techniques and thermography. In this work, we report the use of the abovementioned techniques for improved interpretation of the results.

  9. A Lamb waves based statistical approach to structural health monitoring of carbon fibre reinforced polymer composites.

    Science.gov (United States)

    Carboni, Michele; Gianneo, Andrea; Giglio, Marco

    2015-07-01

    This research investigates a Lamb-wave based structural health monitoring approach matching an out-of-phase actuation of a pair of piezoceramic transducers at low frequency. The target is a typical quasi-isotropic carbon fibre reinforced polymer aeronautical laminate subjected to artificial, via Teflon patches, and natural, via suitable low velocity drop weight impact tests, delaminations. The performance and main influencing factors of such an approach are studied through a Design of Experiment statistical method, considering both Pulse Echo and Pitch Catch configurations of PZT sensors. Results show that some factors and their interactions can effectively influence the detection of a delamination-like damage. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Low-velocity impact damage characterization of carbon fiber reinforced polymer (CFRP) using infrared thermography

    Science.gov (United States)

    Li, Yin; Zhang, Wei; Yang, Zheng-wei; Zhang, Jin-yu; Tao, Sheng-jie

    2016-05-01

    Carbon fiber reinforced polymer (CFRP) after low-velocity impact is detected using infrared thermography, and different damages in the impacted composites are analyzed in the thermal maps. The thermal conductivity under pulse stimulation, frictional heating and thermal conductivity under ultrasonic stimulation of CFRP containing low-velocity impact damage are simulated using numerical simulation method. Then, the specimens successively exposed to the low-velocity impact are respectively detected using the pulse infrared thermography and ultrasonic infrared thermography. Through the numerical simulation and experimental investigation, the results obtained show that the combination of the above two detection methods can greatly improve the capability for detecting and evaluating the impact damage in CFRP. Different damages correspond to different infrared thermal images. The delamination damage, matrix cracking and fiber breakage are characterized as the block-shape hot spot, line-shape hot spot, and

  11. In Plan Shear Retrofit of Masonry Walls with Fibre Reinforced Polymer Composites Experimental Investigations

    Directory of Open Access Journals (Sweden)

    Tamás Nagy-György

    2006-01-01

    Full Text Available The paper presents the results from tests on clay brick masonry walls strengthened using fiber reinforced polymer (FRP composites. Five 1.50x1.50 m wall specimens have been subjected to pure in plan shear loads up to failure and then retrofitted on one side, with different types, percentages and lay-ups of the fiber sheets. Based on the experi¬mental results, it was proven the effectiveness of using externally bonded composites for retrofitting brick masonry walls, with less disruption during strengthening, and in this way with reduced costs compared with other conventional repairing and strengthening tech¬niques. Performances of the different strengthening configurations were compared in terms of ultimate load, strain in composite and failure mechanism.

  12. Recycling carbon fibre reinforced polymers for structural applications: technology review and market outlook.

    Science.gov (United States)

    Pimenta, Soraia; Pinho, Silvestre T

    2011-02-01

    Both environmental and economic factors have driven the development of recycling routes for the increasing amount of carbon fibre reinforced polymer (CFRP) waste generated. This paper presents a review of the current status and outlook of CFRP recycling operations, focusing on state-of-the-art fibre reclamation and re-manufacturing processes, and on the commercialisation and potential applications of recycled products. It is shown that several recycling and re-manufacturing processes are reaching a mature stage, with implementations at commercial scales in operation, production of recycled CFRPs having competitive structural performances, and demonstrator components having been manufactured. The major challenges for the sound establishment of a CFRP recycling industry and the development of markets for the recyclates are summarised; the potential for introducing recycled CFRPs in structural components is discussed, and likely promising applications are investigated. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Strength Analysis of the Carbon-Fiber Reinforced Polymer Impeller Based on Fluid Solid Coupling Method

    Directory of Open Access Journals (Sweden)

    Jinbao Lin

    2014-01-01

    Full Text Available Carbon-fiber reinforced polymer material impeller is designed for the centrifugal pump to deliver corrosive, toxic, and abrasive media in the chemical and pharmaceutical industries. The pressure-velocity coupling fields in the pump are obtained from the CFD simulation. The stress distribution of the impeller couple caused by the flow water pressure and rotation centrifugal force of the blade is analyzed using one-way fluid-solid coupling method. Results show that the strength of the impeller can meet the requirement of the centrifugal pumps, and the largest stress occurred around the blades root on a pressure side of blade surface. Due to the existence of stress concentration at the blades root, the fatigue limit of the impeller would be reduced greatly. In the further structure optimal design, the blade root should be strengthened.

  14. Carbon Fiber Reinforced Polymer with Shredded Fibers: Quasi-Isotropic Material Properties and Antenna Performance

    Directory of Open Access Journals (Sweden)

    Gerald Artner

    2017-01-01

    Full Text Available A carbon fiber reinforced polymer (CFRP laminate, with the top layer consisting of shredded fibers, is proposed and manufactured. The shredded fibers are aligned randomly on the surface to achieve a more isotropic conductivity, as is desired in antenna applications. Moreover, fiber shreds can be recycled from carbon fiber composites. Conductivity, permittivity, and permeability are obtained with the Nicolson-Ross-Weir method from material samples measured inside rectangular waveguides in the frequency range of 4 to 6 GHz. The decrease in material anisotropy results in negligible influence on antennas. This is shown by measuring the proposed CFRP as ground plane material for both a narrowband wire monopole antenna for 5.9 GHz and an ultrawideband conical monopole antenna for 1–10 GHz. For comparison, all measurements are repeated with a twill-weave CFRP.

  15. Improved Bond Equations for Fiber-Reinforced Polymer Bars in Concrete

    Science.gov (United States)

    Pour, Sadaf Moallemi; Alam, M. Shahria; Milani, Abbas S.

    2016-01-01

    This paper explores a set of new equations to predict the bond strength between fiber reinforced polymer (FRP) rebar and concrete. The proposed equations are based on a comprehensive statistical analysis and existing experimental results in the literature. Namely, the most effective parameters on bond behavior of FRP concrete were first identified by applying a factorial analysis on a part of the available database. Then the database that contains 250 pullout tests were divided into four groups based on the concrete compressive strength and the rebar surface. Afterward, nonlinear regression analysis was performed for each study group in order to determine the bond equations. The results show that the proposed equations can predict bond strengths more accurately compared to the other previously reported models. PMID:28773859

  16. Improved Bond Equations for Fiber-Reinforced Polymer Bars in Concrete

    Directory of Open Access Journals (Sweden)

    Sadaf Moallemi Pour

    2016-08-01

    Full Text Available This paper explores a set of new equations to predict the bond strength between fiber reinforced polymer (FRP rebar and concrete. The proposed equations are based on a comprehensive statistical analysis and existing experimental results in the literature. Namely, the most effective parameters on bond behavior of FRP concrete were first identified by applying a factorial analysis on a part of the available database. Then the database that contains 250 pullout tests were divided into four groups based on the concrete compressive strength and the rebar surface. Afterward, nonlinear regression analysis was performed for each study group in order to determine the bond equations. The results show that the proposed equations can predict bond strengths more accurately compared to the other previously reported models.

  17. Nondestructive Evaluation of Carbon Fiber Reinforced Polymer Composites Using Reflective Terahertz Imaging

    Directory of Open Access Journals (Sweden)

    Jin Zhang

    2016-06-01

    Full Text Available Terahertz (THz time-domain spectroscopy (TDS imaging is considered a nondestructive evaluation method for composite materials used for examining various defects of carbon fiber reinforced polymer (CFRP composites and fire-retardant coatings in the reflective imaging modality. We demonstrate that hidden defects simulated by Teflon artificial inserts are imaged clearly in the perpendicular polarization mode. The THz TDS technique is also used to measure the thickness of thin fire-retardant coatings on CFRP composites with a typical accuracy of about 10 micrometers. In addition, coating debonding is successfully imaged based on the time-delay difference of the time-domain waveforms between closely adhered and debonded sample locations.

  18. Study on acoustic emission of carbon fiber reinforced polymer fracture under noisy environment

    Science.gov (United States)

    Tao, Deng; Jianhui, Lin; Yan, Huang

    2017-05-01

    A new method of High Speed Train Fiber Reinforced Polymer AE signal extraction based on Modified Ensemble Empirical Mode Decomposition (MEEMD) was presented here. Because EMD acts as a dyadic filter bank, in this method, amplitude of the added noise in accordance with a Linear-Sinusoidal (L-S) spectrum, and expound how to assemble the noise. The sifting number was set by frequency from high to low. Calculate IMF's Segment sample entropy along the timeline, which take a larger proportion was identified as an AE events. The experimental result shows that the L-S noise spectrum and sifting number could restrain the mode mixing and the little wave vanish. MEEMD obtains a tangible physical meaning and improved results compared with the original EEMD. Segment sample entropy could captured the AE events in a continuous monitoring data. The AE signals was intuitive reflect in the Hilbert spectrogram.

  19. Electrical impedance spectroscopy for measuring the impedance response of carbon-fiber-reinforced polymer composite laminates

    KAUST Repository

    Almuhammadi, Khaled

    2017-02-16

    Techniques that monitor the change in the electrical properties of materials are promising for both non-destructive testing and structural health monitoring of carbon-fiber-reinforced polymers (CFRPs). However, achieving reliable monitoring using these techniques requires an in-depth understanding of the impedance response of these materials when subjected to an alternating electrical excitation, information that is only partially available in the literature. In this work, we investigate the electrical impedance spectroscopy response at various frequencies of laminates chosen to be representative of classical layups employed in composite structures. We clarify the relationship between the frequency of the electrical current, the conductivity of the surface ply and the probing depth for different CFRP configurations for more efficient electrical signal-based inspections. We also investigate the effect of the amplitude of the input signal.

  20. Influence of attenuation on acoustic emission signals in carbon fiber reinforced polymer panels.

    Science.gov (United States)

    Asamene, Kassahun; Hudson, Larry; Sundaresan, Mannur

    2015-05-01

    Influence of attenuation on acoustic emission (AE) signals in Carbon Fiber Reinforced Polymer (CFRP) crossply and quasi-isotropic panels is examined in this paper. Attenuation coefficients of the fundamental antisymmetric (A0) and symmetric (S0) wave modes were determined experimentally along different directions for the two types of CFRP panels. In the frequency range from 100 kHz to 500 kHz, the A0 mode undergoes significantly greater changes due to material related attenuation compared to the S0 mode. Moderate to strong changes in the attenuation levels were noted with propagation directions. Such mode and frequency dependent attenuation introduces major changes in the characteristics of AE signals depending on the position of the AE sensor relative to the source. Results from finite element simulations of a microscopic damage event in the composite laminates are used to illustrate attenuation related changes in modal and frequency components of AE signals. Published by Elsevier B.V.

  1. Antibacterial Efficiency of Hydroxyapatite Biomaterials with Biodegradable Polylactic Acid and Polycaprolactone Polymers Saturated with Antibiotics / Bionoārdāmu Polimēru Saturošu Un Ar Antibiotiskajām Vielām Piesūcinātu Biomateriālu Antibakteriālās Efektivitātes Noteikšana

    Directory of Open Access Journals (Sweden)

    Kroiča Juta

    2016-08-01

    Full Text Available Infections continue to spread in all fields of medicine, and especially in the field of implant biomaterial surgery, and not only during the surgery, but also after surgery. Reducing the adhesion of bacteria could decrease the possibility of biomaterial-associated infections. Bacterial adhesion could be reduced by local antibiotic release from the biomaterial. In this in vitro study, hydroxyapatite biomaterials with antibiotics and biodegradable polymers were tested for their ability to reduce bacteria adhesion and biofilm development. This study examined the antibacterial efficiency of hydroxyapatite biomaterials with antibiotics and biodegradable polymers against Staphylococcus epidermidis and Pseudomonas aeruginosa. The study found that hydroxyapatite biomaterials with antibiotics and biodegradable polymers show longer antibacterial properties than hydroxyapatite biomaterials with antibiotics against both bacterial cultures. Therefore, the results of this study demonstrated that biomaterials that are coated with biodegradable polymers release antibiotics from biomaterial samples for a longer period of time and may be useful for reducing bacterial adhesion on orthopedic implants.

  2. Development of multifunctional fiber reinforced polymer composites through ZnO nanowire arrays

    Science.gov (United States)

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

    2016-04-01

    Piezoelectric nanowires, in particular zinc oxide (ZnO) nanowires, have been vastly used in the fabrication of electromechanical devices to convert wasted mechanical energy into useful electrical energy. Over recent years, the growth of vertically aligned ZnO nanowires on various structural fibers has led to the development of fiber-based nanostructured energy harvesting devices. However, the development of more realistic energy harvesters that are capable of continuous power generation requires a sufficient mechanical strength to withstand typical structural loading conditions. Yet, a durable, multifunctional material system has not been developed thoroughly enough to generate electrical power without deteriorating the mechanical performance. Here, a hybrid composite energy harvester is fabricated in a hierarchical design that provides both efficient power generating capabilities while enhancing the structural properties of the fiber reinforced polymer composite. Through a simple and low-cost process, a modified aramid fabric with vertically aligned ZnO nanowires grown on the fiber surface is embedded between woven carbon fabrics, which serve as the structural reinforcement as well as the top and the bottom electrodes of the nanowire arrays. The performance of the developed multifunctional composite is characterized through direct vibration excitation and tensile strength examination.

  3. Dual Function Behavior of Carbon Fiber-Reinforced Polymer in Simulated Pore Solution

    Directory of Open Access Journals (Sweden)

    Ji-Hua Zhu

    2016-02-01

    Full Text Available The mechanical and electrochemical performance of carbon fiber-reinforced polymer (CFRP were investigated regarding a novel improvement in the load-carrying capacity and durability of reinforced concrete structures by adopting CFRP as both a structural strengthener and an anode of the impressed current cathodic protection (ICCP system. The mechanical and anode performance of CFRP were investigated in an aqueous pore solution in which the electrolytes were available to the anode in a cured concrete structure. Accelerated polarization tests were designed with different test durations and various levels of applied currents in accordance with the international standard. The CFRP specimens were mechanically characterized after polarization. The measured feeding voltage and potential during the test period indicates CFRP have stable anode performance in a simulated pore solution. Two failure modes were observed through tensile testing. The tensile properties of the post-polarization CFRP specimens declined with an increased charge density. The CFRP demonstrated success as a structural strengthener and ICCP anode. We propose a mathematic model predicting the tensile strengths of CFRP with varied impressed charge densities.

  4. Performance of reinforced polymer ablators exposed to a solid rocket motor exhaust. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Boyer, C.; Burgess, T.; Bowen, J.; Deloach, K.; Talmy, I.

    1992-10-01

    Summarized in this report is the effort by the Naval Surface Warfare Center Dahlgren Division (NSWCDD) and FMC Corporation (a launcher manufacturer) to identify new high performance ablators suitable for use on Navy guided missile launchers (GML) and ships' structures. The goal is to reduce ablator erosion by 25 to 50 percent compared to that of the existing ablators such as MXBE350 (rubbermodified phenolic containing glass fiber reinforcement). This reduction in erosion would significantly increase the number of new missiles with higher-thrust, longer burn rocket motors that can be launched prior to ablator refurbishment. In fact, there are a number of new Navy missiles being considered for development and introduction into existing GML: e.g., the Antisatellite Missile (ASM) and the Theater High-Altitude Area Defense (THAAD) Missile. The U.S. Navy experimentally evaluated the eight best fiber-reinforced, polymer composites from a possible field of 25 off-the-shelf ablators previously screened by FMC Corporation. They were tested by the Navy in highly aluminized solid rocket motor exhaust plumes to determine their ability to resist erosion and to insulate.... Ablator, Guided Missile Launchers, Erosion, Tactical missiles, Convective heating, Solid rocket motors, Aluminum oxide particles.

  5. Dual Function Behavior of Carbon Fiber-Reinforced Polymer in Simulated Pore Solution.

    Science.gov (United States)

    Zhu, Ji-Hua; Guo, Guanping; Wei, Liangliang; Zhu, Miaochang; Chen, Xianchuan

    2016-02-06

    The mechanical and electrochemical performance of carbon fiber-reinforced polymer (CFRP) were investigated regarding a novel improvement in the load-carrying capacity and durability of reinforced concrete structures by adopting CFRP as both a structural strengthener and an anode of the impressed current cathodic protection (ICCP) system. The mechanical and anode performance of CFRP were investigated in an aqueous pore solution in which the electrolytes were available to the anode in a cured concrete structure. Accelerated polarization tests were designed with different test durations and various levels of applied currents in accordance with the international standard. The CFRP specimens were mechanically characterized after polarization. The measured feeding voltage and potential during the test period indicates CFRP have stable anode performance in a simulated pore solution. Two failure modes were observed through tensile testing. The tensile properties of the post-polarization CFRP specimens declined with an increased charge density. The CFRP demonstrated success as a structural strengthener and ICCP anode. We propose a mathematic model predicting the tensile strengths of CFRP with varied impressed charge densities.

  6. Fabrication Of Carbon-Boron Reinforced Dry Polymer Matrix Composite Tape

    Science.gov (United States)

    Belvin, Harry L.; Cano, Roberto J.; Treasure, Monte; Shahood, Thomas W.

    1999-01-01

    Future generation aerospace vehicles will require specialized hybrid material forms for component structure fabrication. For this reason, high temperature composite prepregs in both dry and wet forms are being developed at NASA Langley Research Center (LaRC). In an attempt to improve compressive properties of carbon fiber reinforced composites, a hybrid carbon-boron tape was developed and used to fabricate composite laminates which were subsequently cut into flexural and compression specimens and tested. The hybrid material, given the designation HYCARB, was fabricated by modifying a previously developed process for the manufacture of dry polymer matrix composite (PMC) tape at LaRC. In this work, boron fibers were processed with IM7/LaRC(TradeMark)IAX poly(amide acid) solution-coated prepreg to form a dry hybrid tape for Automated Tow Placement (ATP). Boron fibers were encapsulated between two (2) layers of reduced volatile, low fiber areal weight poly(amide acid) solution-coated prepreg. The hybrid prepreg was then fully imidized and consolidated into a dry tape suitable for ATP. The fabrication of a hybrid boron material form for tow placement aids in the reduction of the overall manufacturing cost of boron reinforced composites, while realizing the improved compression strengths. Composite specimens were press-molded from the hybrid material and exhibited excellent mechanical properties.

  7. An Experimental Study on Concrete Flat Slabs Prestressed with Carbon Fibre Reinforced Polymer Sheets

    Directory of Open Access Journals (Sweden)

    Yin Shen

    2015-01-01

    Full Text Available Carbon fibre reinforced polymer (CFRP is currently used to reinforce buildings in civil engineering in the common forms of sheets, while the utilization efficiency of a CFRP materials greatly decreased when the CFRP material is directly bonded to the structure because of the lack of the effect of the exertion of a prestress. A paper spool-inspired anchoring method is proposed to overcome the shearing problem in the anchoring system through the friction between layers. Anchoring and jack-up tensioning devices for CFRP sheets are also designed and produced. A prestress is successfully applied to single and multiple CFRP sheets (80% tensioning strength is achieved, thus verifying the tensioning effect of the prestress. Based on these results, prestressed concrete flat slabs were designed with pretensioned CFRP sheets. The corresponding mechanical properties of the concrete flat slabs are tested to verify the feasibility of using CFRP sheets to apply a prestress. The results show that the uniformity of the fibre stress during the tensioning of the CFRP sheet is the key to the success of the application of the prestress.

  8. Investigation of Crack Resistance in Single Walled Carbon Nanotube Reinforced Polymer Composites Based on FEM

    Directory of Open Access Journals (Sweden)

    Hosein Hemmatian

    2012-10-01

    Full Text Available Carbon nanotube (CNT is considered as a new generation of material possessing superior mechanical, thermal and electrical properties. The applications of CNT, especially in composite materials, i.e. carbon nanotube reinforced polymer have received great attention and interest in recent years. To characterize the influence of CNT on the stress intensity factor of nanocomposites, three fracture modes (opening, shearing and tearing are considered. The stress intensity factor of nanocomposites is evaluated using a representative volume element (RVE based on the continuum mechanics and finite element method (FEM. Inter-atomic interactions of CNT are simulated by beam elements in the finite element (FE model. Non-linear springbased line elements are employed to simulate the van der Waals (vdW bonds. In all fracture modes, the stress intensity factor was determined for pure matrix and matrix reinforced with single-walled carbon nanotube (SWCNT. Numerical results indicate that the load carrying capacities of the CNTs in a matrix are evident. Addition of CNTs in a matrix can increase the stiffness of the composite. Finally, the results showed that utilizing of SWCNT decreased the stress intensity factor and improved crack resistance.

  9. Double-Sided Terahertz Imaging of Multilayered Glass Fiber-Reinforced Polymer

    Directory of Open Access Journals (Sweden)

    Przemyslaw Lopato

    2017-06-01

    Full Text Available Polymer matrix composites (PMC play important roles in modern industry. Increasing the number of such structures in aerospace, construction, and automotive applications enforces continuous monitoring of their condition. Nondestructive inspection of layered composite materials is much more complicated process than evaluation of homogenous, (mostly metallic structures. Several nondestructive methods are utilized in this case (ultrasonics, shearography, tap testing, acoustic emission, digital radiography, infrared imaging but none of them gives full description of evaluated structures. Thus, further development of NDT techniques should be studied. A pulsed terahertz method seems to be a good candidate for layered PMC inspection. It is based on picosecond electromagnetic pulses interacting with the evaluated structure. Differences of dielectric parameters enables detection of a particular layer in a layered material. In the case of multilayered structures, only layers close to surface can be detected. The response of deeper ones is averaged because of multiple reflections. In this paper a novel inspection procedure with a data processing algorithm is introduced. It is based on a double-sided measurement, acquired signal deconvolution, and data combining. In order to verify the application of the algorithm stress-subjected glass fiber-reinforced polymer (GFRP was evaluated. The obtained results enabled detection and detailed analysis of delaminations introduced by stress treatment and proved the applicability of the proposed algorithm.

  10. Preparation and Properties of Polymer/Vermiculite Hybrid Superabsorbent Reinforced by Fiber for Enhanced Oil Recovery

    Directory of Open Access Journals (Sweden)

    Fayang Jin

    2014-01-01

    Full Text Available A series of polymer/clay hybrid superabsorbent composites (SACFs comprising acrylamide, acrylic acid, sodium 2-acrylamido-tetradecyl sulfonate, fiber, and vermiculite by in situ intercalation and exfoliated method was successfully synthesized. The structure of SACFs was characterized by IR, SXRD, and SEM measurements. Much notable absorbency for SACF-2 was observed compared to that for SACF-1 in the absence of hydrophobic group in the high cationic solution due to the alkyl carbon chain and sulfonic acid group of hydrophobic moistures protecting the cations from attacking the carboxylate groups. What is more, high temperature fiber which acts as bridge connection for the polymeric network structure enhanced both toughness and strength for SACF-4 in the harsh conditions. At the total dissolved substance of 212000 mg/L for Tarim Basin injected water and the temperature of 120°C, desired absorbency as well as water retaining property for SACF-4 was observed during the long period of thermal ageing. Core flooding experiments demonstrated that SACFs could migrate as amoeba in the porous medium and accumulated in the narrow channel to adjust injection profile, promoting the subsequent water diverting into the unswept zones. Finally, characteristic parameters for SACFs calculated from flooding experiment further confirmed these polymer/clay hybrid composites reinforced by fiber would have robust application in the mature oilfield for profile control.

  11. Parametric Study of Strain Rate Effects on Nanoparticle-Reinforced Polymer Composites

    Directory of Open Access Journals (Sweden)

    B. Soltannia

    2016-01-01

    Full Text Available Crashworthiness, energy absorption capacity, and safety are important factors in the design of lightweight vehicles made of fiber-reinforced polymer composite (FRP components. The relatively recent emergence of the nanotechnology industry has presented a novel means to augment the mechanical properties of various materials. As a result, recent attempts have contemplated the use of nanoparticles to further improve the resiliency of resins, especially when resins are used for mating FRP components. Therefore, a comprehensive understanding of the response of nanoreinforced polymer composites, subjected to various rates of loading, is of paramount importance for developing reliable structures. In this paper, the effects of nanoreinforcement on the mechanical response of a commonly used epoxy resin subjected to four different strain rates, are systematically investigated. The results are then compared to those of the neat resin. To characterize the mechanical properties of the nanocomposite, a combination of the strain rate-dependent mechanical (SRDM model of Goldberg and his coworkers and Halpin-Tsai’s micromechanical approach is employed. Subsequently, a parametric study is conducted to ascertain the influences of particle type and their weight percentage. Finally, the numerical results are compared to the experimental data obtained from testing of the neat and the nanoreinforced epoxy resin.

  12. A carbon fiber reinforced polymer cage for vertebral body replacement: technical note.

    Science.gov (United States)

    Ciappetta, P; Boriani, S; Fava, G P

    1997-11-01

    We analyzed the surgical technique used for the replacement of damaged vertebral bodies of the thoracolumbar spine and the carbon fiber reinforced polymer (CFRP) cages that are used to replace the pathological vertebral bodies. We also evaluated the biomechanical properties of carbon composite materials used in spinal surgery. The surgical technique of CFRP implants may be divided into two distinct steps, i.e., assembling the components that will replace the pathological vertebral bodies and connecting the cage to an osteosynthetic system to immobilize the cage. The CFRP cages, made of Ultrapek polymer and AS-4 pyrolytic carbon fiber (AcroMed, Rotterdam, The Netherlands), are of different sizes and may be placed one on top of the other and fixed together with a titanium rod. These components are hollow to allow fragments of bone to be pressed manually into them and present threaded holes at 15, 30, and 90 degrees on the external surface, permitting the insertion of screws to connect the cage to an anterior or posterior osteosynthetic system. To date, we have used CFRP cages in 13 patients undergoing corporectomies and 10 patients undergoing spondylectomies. None of our patients have reported complications. CFRP implants offer several advantages compared with titanium or surgical grade stainless steel implants, demonstrating high versatility and outstanding biological and mechanical properties. Furthermore, CFRP implants are radiolucent and do not hinder radiographic evaluation of bone fusion, allowing for better follow-up studies.

  13. Carbon Nanotubes Reinforced Composites for Biomedical Applications

    National Research Council Canada - National Science Library

    Wang, Wei; Zhu, Yuhe; Liao, Susan; Li, Jiajia

    2014-01-01

    .... The review introduced fabrication of CNTs reinforced composites (CNTs reinforced metal matrix composites, CNTs reinforced polymer matrix composites, and CNTs reinforced ceramic matrix composites...

  14. Effect of Thermal Cycling on the Tensile Behavior of Polymer Composites Reinforced by Basalt and Carbon Fibers

    Science.gov (United States)

    Khalili, S. Mohammad Reza; Najafi, Moslem; Eslami-Farsani, Reza

    2017-01-01

    The aim of the present work was to investigate the effect of thermal cycling on the tensile behavior of three types of polymer-matrix composites — a phenolic resin reinforced with woven basalt fibers, woven carbon fibers, and hybrid basalt and carbon fibers — in an ambient environment. For this purpose, tensile tests were performed on specimens previously subjected to a certain number of thermal cycles. The ultimate tensile strength of the specimen reinforced with woven basalt fibers had by 5% after thermal cycling, but the strength of the specimen with woven carbon fibers had reduced to a value by 11% higher than that before thermal cycling.

  15. Analysis of acoustic emission cumulative signal strength of steel fibre reinforced concrete (SFRC) beams strengthened with carbon fibre reinforced polymer (CFRP)

    Science.gov (United States)

    Abdul Hakeem, Z.; Noorsuhada, M. N.; Azmi, I.; Noor Syafeekha, M. S.; Soffian Noor, M. S.

    2017-12-01

    In this study, steel fibre reinforced concrete (SFRC) beams strengthened with carbon fibre reinforced polymer (CFRP) were investigated using acoustic emission (AE) technique. Three beams with dimension of 150 mm width, 200 mm depth and 1500 mm length were fabricated. The results generated from AE parameters were analysed as well as signal strength and cumulative signal strength. Three relationships were produced namely load versus deflection, signal strength versus time and cumulative signal strength with respect to time. Each relationship indicates significant physical behaviour as the crack propagated in the beams. It is found that an addition of steel fibre in the concrete mix and strengthening of CFRP increase the ultimate load of the beam and the activity of signal strength. Moreover, the highest signal strength generated can be identified. From the study, the occurrence of crack in the beam can be predicted using AE signal strength.

  16. Effects of the Amount and Shape of Carbon Fiber-Reinforced Polymer Strengthening Elements on the Ductile Behavior of Reinforced Concrete Beams

    Science.gov (United States)

    Hong, Sungnam

    2014-09-01

    A series of beam tests were performed to evaluate the ductility of reinforced concrete (RC) beams strengthened with carbon-fiber-reinforced polymer (CFRP) elements. A total of nine RC beams were produced and loaded up to failure in three-point bending under deflection control. In addition, the amount and shape of the CFRP elements (plates/sheets) were considered as the key test variables. Test results revealed that the strengthening with CFRP elements in the width direction was more effective than the strengthening across their height. The energy method used in an analysis showed that the energy ratio of the beams strengthened with CFRP plates were half or less than half of the energy ratio of the beams strengthened with CFRP sheets. In addition, the ductility of the beams decreased as the strengthening ratio of the CFRP elements increased.

  17. Buckling of Carbon Nanotube-Reinforced Polymer Laminated Composite Materials Subjected to Axial Compression and Shear Loadings

    Science.gov (United States)

    Riddick, J. C.; Gates, T. S.; Frankland, S.-J. V.

    2005-01-01

    A multi-scale method to predict the stiffness and stability properties of carbon nanotube-reinforced laminates has been developed. This method is used in the prediction of the buckling behavior of laminated carbon nanotube-polyethylene composites formed by stacking layers of carbon nanotube-reinforced polymer with the nanotube alignment axes of each layer oriented in different directions. Linking of intrinsic, nanoscale-material definitions to finite scale-structural properties is achieved via a hierarchical approach in which the elastic properties of the reinforced layers are predicted by an equivalent continuum modeling technique. Solutions for infinitely long symmetrically laminated nanotube-reinforced laminates with simply-supported or clamped edges subjected to axial compression and shear loadings are presented. The study focuses on the influence of nanotube volume fraction, length, orientation, and functionalization on finite-scale laminate response. Results indicate that for the selected laminate configurations considered in this study, angle-ply laminates composed of aligned, non-functionalized carbon nanotube-reinforced lamina exhibit the greatest buckling resistance with 1% nanotube volume fraction of 450 nm uniformly-distributed carbon nanotubes. In addition, hybrid laminates were considered by varying either the volume fraction or nanotube length through-the-thickness of a quasi-isotropic laminate. The ratio of buckling load-to-nanotube weight percent for the hybrid laminates considered indicate the potential for increasing the buckling efficiency of nanotube-reinforced laminates by optimizing nanotube size and proportion with respect to laminate configuration.

  18. Mechanical Property Evaluation of Palm/Glass Sandwiched Fiber Reinforced Polymer Composite in Comparison with few natural composites

    Science.gov (United States)

    Raja Dhas, J. Edwin; Pradeep, P.

    2017-10-01

    Natural fibers available plenty can be used as reinforcements in development of eco friendly polymer composites. The less utilized palm leaf stalk fibers sandwiched with artificial glass fibers was researched in this work to have a better reinforcement in preparing a green composite. The commercially available polyester resin blend with coconut shell filler in nano form was used as matrix to sandwich these composites. Naturally available Fibers of palm leaf stalk, coconut leaf stalk, raffia and oil palm were extracted and treated with potassium permanganate solution which enhances the properties. For experimentation four different plates were fabricated using these fibers adopting hand lay-up method. These sandwiched composite plates are further machined to obtain ASTM standards Specimens which are mechanically tested as per standards. Experimental results reveal that the alkali treated palm leaf stalk fiber based polymer composite shows appreciable results than the others. Hence the developed composite can be recommended for fabrication of automobile parts.

  19. Life cycle strain monitoring in glass fibre reinforced polymer laminates using embedded fibre Bragg grating sensors from manufacturing to failure

    DEFF Research Database (Denmark)

    Nielsen, Michael Wenani; Schmidt, Jacob Wittrup; Høgh, Jacob Herold

    2013-01-01

    A holistic approach to strain monitoring in fibre-reinforced polymer composites is presented using embedded fibre Bragg grating sensors. Internal strains are monitored in unidirectional E-glass/epoxy laminate beams during vacuum infusion, curing, post-curing and subsequent loading in flexure until...... failure. The internal process-induced strain development is investigated through use of different cure schedules and tool/part interactions. The fibre Bragg grating sensors successfully monitor resin flow front progression during infusion, and strain development during curing, representative...... of the different cure temperatures and tool/part interfaces used. Substantial internal process-induced strains develop in the transverse fibre direction, which should be taken into consideration when designing fibre-reinforced polymer laminates. Flexure tests indicate no significant difference in the mechanical...

  20. Studies on single polymer composites of poly(methyl methacrylate) reinforced with electrospun nanofibers with a focus on their dynamic mechanical properties

    CSIR Research Space (South Africa)

    Matabola, KP

    2011-07-01

    Full Text Available The dynamic mechanical properties of single polymer composites of poly(methyl methacrylate) (PMMA) reinforced with electrospun PMMA nanofibers of different diameters are reported. The effect of electrospinning parameters on the morphology...

  1. Semiempirical Methodology for Estimating the Service Life of Concrete Deck Panels Strengthened with Fiber-Reinforced Polymer

    OpenAIRE

    Eon-Kyoung Kim; Hongseob Oh; Jongsung Sim

    2014-01-01

    Deterioration of concrete bridge decks affects their durability, safety, and function. It is therefore necessary to conduct structural rehabilitation of damaged concrete decks by strengthening them with fiber-reinforced polymer. Of the recent studies on the strengthened structures, most have focused on static behavior; only a few studies have investigated fatigue behavior. Accurate analysis of fatigue in concrete deck performance requires a more realistic simulated moving load. This study dev...

  2. Structure and properties of short fiber reinforced polymer composite and hybrid composite fabricated by injection molding process

    OpenAIRE

    Uawongsuwan, Putinun

    2015-01-01

    Short fiber reinforced polymer composites have found extensive applications in many fields due to their low cost, easy processing and superior mechanical properties over the neat thermoplastics. For interpreting the mechanical properties of composite by several variable parameters, additional measurements are required when changes occur in the composite system variables. Thus, experiments may be time consuming and cost prohibitive. Therefore, theoretical models of determining composite proper...

  3. Fiber Reinforced Polymer and Polypropylene Composite Retrofitting Technique for Masonry Structures

    Directory of Open Access Journals (Sweden)

    Saleem Muhammad Umair

    2015-05-01

    Full Text Available In the current research work, an attempt is made to increase the seismic capacity of unreinforced masonry (URM structures by proposing a new composite material which can improve shear strength and deformation capacity of URM wall systems. Fiber Reinforced Polymer (FRP having high tensile and shear stiffness can significantly increase in-plane and out-of-plane strength of masonry walls, but, inherently, FRP strengthened wall systems exhibit brittle failure under extreme seismic loading. Polypropylene (PP-band is a low cost material with sufficient ductility and deformation capacity. Keeping in view the behavior of FRP and PP-band, a composite of FRP and PP-band is proposed for retrofitting of URM walls. Mechanical behavior of the proposed composite material is assessed by carrying out an in-plane diagonal compression test and an out-of-plane bending test on twenty-five 1/4-scaled masonry wall panels. Experimental plan for each panel, URM, PP-band retrofitted, FRP retrofitted and FRP + PP-band retrofitted masonry, is diagonal compression test and three-point bending test. Experimental results have determined that FRP + PP-band composite increased, not only the initial peak strength, but also the ductility, deformation capacity and residual strength of URM wall systems.

  4. Warpage Analysis of Electroplated Cu Films on Fiber-Reinforced Polymer Packaging Substrates

    Directory of Open Access Journals (Sweden)

    Cheolgyu Kim

    2015-06-01

    Full Text Available This paper presents a warpage analysis method that predicts the warpage behavior of electroplated Cu films on glass fiber-reinforced polymer (GFRP packaging substrates. The analysis method is performed using the following sequence: fabricate specimens for scanning 3D contours, transform 3D data into curvatures, compute the built-in stress of the film using a stress-curvature analytic model, and verify it through comparisons of the finite element method (FEM simulations with the measured data. The curvature is used to describe the deflection and warpage modes and orientations of the specimen. Two primary factors that affect the warpage behavior of the electroplated Cu film on FRP substrate specimens are investigated. The first factor is the built-in stress in a Cu film that explains the room temperature warpage of the specimen under no thermal process. The second factor is the misfit of the coefficient of thermal expansion (CTE between the Cu and FRP layer, which is a dominant factor during the temperature change. The calculated residual stress, and predicted curvatures using FEM simulation throughout the reflow process temperature range between 25 and 180 °C are proven to be accurate by the comparison of the FEM simulations and experiment measurements.

  5. Optimal Electrode Selection for Electrical Resistance Tomography in Carbon Fiber Reinforced Polymer Composites

    Science.gov (United States)

    Escalona Galvis, Luis Waldo; Diaz-Montiel, Paulina; Venkataraman, Satchi

    2017-01-01

    Electrical Resistance Tomography (ERT) offers a non-destructive evaluation (NDE) technique that takes advantage of the inherent electrical properties in carbon fiber reinforced polymer (CFRP) composites for internal damage characterization. This paper investigates a method of optimum selection of sensing configurations for delamination detection in thick cross-ply laminates using ERT. Reduction in the number of sensing locations and measurements is necessary to minimize hardware and computational effort. The present work explores the use of an effective independence (EI) measure originally proposed for sensor location optimization in experimental vibration modal analysis. The EI measure is used for selecting the minimum set of resistance measurements among all possible combinations resulting from selecting sensing electrode pairs. Singular Value Decomposition (SVD) is applied to obtain a spectral representation of the resistance measurements in the laminate for subsequent EI based reduction to take place. The electrical potential field in a CFRP laminate is calculated using finite element analysis (FEA) applied on models for two different laminate layouts considering a set of specified delamination sizes and locations with two different sensing arrangements. The effectiveness of the EI measure in eliminating redundant electrode pairs is demonstrated by performing inverse identification of damage using the full set and the reduced set of resistance measurements. This investigation shows that the EI measure is effective for optimally selecting the electrode pairs needed for resistance measurements in ERT based damage detection. PMID:28772485

  6. Prediction of failure in notched carbon-fibre-reinforced-polymer laminates under multi-axial loading.

    Science.gov (United States)

    Tan, J L Y; Deshpande, V S; Fleck, N A

    2016-07-13

    A damage-based finite-element model is used to predict the fracture behaviour of centre-notched quasi-isotropic carbon-fibre-reinforced-polymer laminates under multi-axial loading. Damage within each ply is associated with fibre tension, fibre compression, matrix tension and matrix compression. Inter-ply delamination is modelled by cohesive interfaces using a traction-separation law. Failure envelopes for a notch and a circular hole are predicted for in-plane multi-axial loading and are in good agreement with the observed failure envelopes from a parallel experimental study. The ply-by-ply (and inter-ply) damage evolution and the critical mechanisms of ultimate failure also agree with the observed damage evolution. It is demonstrated that accurate predictions of notched compressive strength are obtained upon employing the band broadening stress for microbuckling, highlighting the importance of this damage mode in compression. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'. © 2016 The Author(s).

  7. Finite strain formulation of viscoelastic damage model for simulation of fabric reinforced polymers under dynamic loading

    Directory of Open Access Journals (Sweden)

    Treutenaere S.

    2015-01-01

    Full Text Available The use of fabric reinforced polymers in the automotive industry is growing significantly. The high specific stiffness and strength, the ease of shaping as well as the great impact performance of these materials widely encourage their diffusion. The present model increases the predictability of explicit finite element analysis and push the boundaries of the ongoing phenomenological model. Carbon fibre composites made up various preforms were tested by applying different mechanical load up to dynamic loading. This experimental campaign highlighted the physical mechanisms affecting the initial mechanical properties, namely intra- and interlaminar matrix damage, viscoelasticty and fibre failure. The intralaminar behaviour model is based on the explicit formulation of the matrix damage model developed by the ONERA as the given damage formulation correlates with the experimental observation. Coupling with a Maxwell-Wiechert model, the viscoelasticity is included without losing the direct explicit formulation. Additionally, the model is formulated under a total Lagrangian scheme in order to maintain consistency for finite strain. Thus, the material frame-indifference as well as anisotropy are ensured. This allows reorientation of fibres to be taken into account particularly for in-plane shear loading. Moreover, fall within the framework of the total Lagrangian scheme greatly makes the parameter identification easier, as based on the initial configuration. This intralaminar model thus relies upon a physical description of the behaviour of fabric composites and the numerical simulations show a good correlation with the experimental results.

  8. Asset Management Business Model for Design, Realization, and Maintenance of Fibre Reinforced Polymer Bridges

    Directory of Open Access Journals (Sweden)

    Rizal Sebastian

    2013-01-01

    Full Text Available This paper particularly addresses the market implementation of Fibre Reinforced Polymer (FRP for bridges. It presents the concept of demand and supply chain innovation as being investigated within two ongoing European collaborative research projects (FP7 titled Trans-IND and PANTURA. FRP has emerged as a real alternative structural material based on various sustainability considerations, among others the reduced life-cycle cost due to less maintenance needs, longer lifetime, and easiness to repair, replace, or recycle the components. The Trans-IND research project aims to develop and demonstrate new industrialized processes to use FRP for civil infrastructure projects at a large scale. In order to be cost effective, a new value-chain strategy for the design, realization, and maintenance of FRP bridges is required to replace the fragmented supply chain and the one-off approach to a construction project. This paper focuses on the development of new business models based on asset management strategy, which covers the entire demand and supply chains. Research on new business models is supported by the insight into the market and regulatory frameworks in different EU countries. This is based on field surveys across the EU that have been carried out as a part of the Trans-IND and PANTURA collaborative research projects.

  9. Fretting Fatigue Behaviour of Pin-Loaded Thermoset Carbon-Fibre-Reinforced Polymer (CFRP Straps

    Directory of Open Access Journals (Sweden)

    Fabio Baschnagel

    2016-04-01

    Full Text Available This paper focuses on the fretting fatigue behaviour of pin-loaded carbon-fibre-reinforced polymer (CFRP straps studied as models for rigging systems in sailing yachts, for suspenders of arch bridges and for pendent cables in cranes. Eight straps were subjected to an ultimate tensile strength test. In total, 26 straps were subjected to a fretting fatigue test, of which ten did not fail. An S–N curve was generated for a load ratio R of 0.1 and a frequency f of 10 Hz, showing a fatigue limit stress of the straps around the matrix fatigue limit, corresponding to 46% of the straps’ ultimate tensile strength (σUTS. The fatigue limit was defined as 3 million load cycles (N = 3 × 106, but tests were even conducted up to N = 11.09 × 106. Catastrophic failure of the straps was initiated in their vertex areas. Investigations on the residual strength and stiffness properties of straps tested around the fatigue limit stress (for N ≥ 1 × 106 showed little influence of the fatigue loading on these properties. Quasi-static finite element analyses (FEA were conducted. The results obtained from the FEA are in good agreement with the experiments and demonstrate a fibre parallel stress concentration in the vertex area of factor 1.3, under the realistic assumption of a coefficient of friction (cof between pin and strap of 0.5.

  10. Flexural Strength of Carbon Fiber Reinforced Polymer Repaired Cracked Rectangular Hollow Section Steel Beams

    Directory of Open Access Journals (Sweden)

    Tao Chen

    2015-01-01

    Full Text Available The flexural behavior of rectangular hollow section (RHS steel beams with initial crack strengthened externally with carbon fiber reinforced polymer (CFRP plates was studied. Eight specimens were tested under three-point loading to failure. The experimental program included three beams as control specimens and five beams strengthened with CFRP plates with or without prestressing. The load deflection curves were graphed and failure patterns were observed. The yield loads and ultimate loads with or without repairing were compared together with the strain distributions of the CFRP plate. It was concluded that yield loads of cracked beams could be enhanced with repairing. Meanwhile, the ultimate loads were increased to some extent. The effect of repair became significant with the increase of the initial crack depth. The failure patterns of the repaired specimens were similar to those of the control ones. Mechanical clamping at the CFRP plate ends was necessary to avoid premature peeling between the CFRP plate and the steel beam. The stress levels in CFRP plates were relatively low during the tests. The use of prestressing could improve the utilization efficiency of CFRP plates. It could be concluded that the patching repair could be used to restore the load bearing capacity of the deficient steel beams.

  11. AE analysis of delamination crack propagation in carbon fiber-reinforced polymer materials

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Sang Jae; Arakawa, Kazuo [Kyushu University, kasuga (Japan); Chen, Dingding [National University of Defense Technology, Changsha (China); Han, Seung Wook; Choi, Nak Sam [Hanyang University, Seoul (Korea, Republic of)

    2015-01-15

    Delamination fracture behavior was investigated using acoustic emission (AE) analysis on carbon fiber-reinforced polymer (CFRP) samples manufactured using vacuum-assisted resin transfer molding (VARTM). CFRP plate was fabricated using unidirectional carbon fiber fabric with a lay-up of six plies [+30/-30]6 , and a Teflon film was inserted as a starter crack. Test pieces were sectioned from the inlet and vent of the mold, and packed between two rectangular epoxy plates to load using a universal testing machine. The AE signals were monitored during tensile loading using two sensors. The average tensile load of the inlet specimens was slightly larger than that of the vent specimens; however, the data exhibited significant scattering due to non-uniform resin distribution, and there was no statistically significant different between the strength of the samples sectioned from the inlet or outlet of the mold. Each of the specimens exhibited similar AE characteristics, regardless of whether they were from the inlet or vent of the mold. Four kinds of damage mechanism were observed: micro-cracking, fiber-resin matrix debonding, fiber pull-out, and fiber failure; and three stages of the crack propagation process were identified.

  12. Mechanical behavior of connection of pultruded glass fiber reinforced polymer plates using FRP bolts and adhesive

    Science.gov (United States)

    Nhut, Phan Viet; Matsumoto, Yukihiro; Hashimoto, Kunitaro; Kitane, Yasuo

    2017-10-01

    Pultruded Fiber Reinforced Polymers (FRPs) have been increasingly used in civil infrastructure applications due to advanced properties such as high specific strength, lightweight and especially high corrosion resistance. In highly corrosive environment such as chemical and acid environment where metallic by-products are prone to corrosion, the use of adhesive bonding in addition to FRP bolts not only decreases the structure's weight, limits the impacts of aggressive environment but also increases the ultimate strength of the connection and improves the connection stiffness. In this paper, mechanical behavior of pultruded FRP double-lap specimens combined by only FRP bolt as well as both FRP bolt and adhesive under tension tests was investigated by finite element method and experimental data. Two kinds of used adhesive were high strength adhesive and low elastic one. Results show that comparing with bolt-only specimens, connections with both FRP bolt and adhesive had the higher joint strength. Specimens with high strength adhesive had the highest joint strength but the shear out failure and delamination at FRP plates happened suddenly while the low elastic adhesive specimens witnessed the debonding failure and shear out failure alternately in the both sides of connections. Moreover, the stress distributions in the GFRP plates were also investigated and there were good agreements between finite element analysis (FEA) and experimental data achieved in this paper.

  13. Sodium alginate-assisted exfoliation of MoS2 and its reinforcement in polymer nanocomposites.

    Science.gov (United States)

    Xuan, Dandan; Zhou, Yifeng; Nie, Wangyan; Chen, Pengpeng

    2017-01-02

    In this work, molybdenum disulfide (MoS2) nanosheets were facilely prepared by direct exfoliation of MoS2 in aqueous media with the assistance of sodium alginate (SA). Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectra results showed that the raw MoS2 was successfully exfoliated into few-layer MoS2 nanosheets (SA-MoS2). FTIR and thermal gravimetric analysis (TGA) investigations showed that the obtained MoS2 nanosheets were modified by SA after exfoliation and improved dispersion in water were achieved. The obtained SA-MoS2 nanosheets were employed to reinforce the water-soluble polymer SA. No obvious macroscopic phase separation could be found from the SA/SA-MoS2 films. Dynamic mechanical analysis (DMA) results showed that almost 9 times enhancement for the storage modulus of SA was achieved with the incorporation of only 0.5wt% of SA-MoS2, and the thermal stability of SA was also found improved with the addition of SA-MoS2 according to the thermal gravimetric analysis TGA results. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Bond Behavior of Historical Clay Bricks Strengthened with Steel Reinforced Polymers (SRP).

    Science.gov (United States)

    Grande, Ernesto; Imbimbo, Maura; Sacco, Elio

    2011-03-21

    In the strengthening interventions of past and historical masonry constructions, the non-standardized manufacture processes, the ageing and the damage of masonry units, could significantly affect the properties of the surfaces where strengthening materials are applied. This aspect requires particular care in evaluating the performance of externally bonded strengthening layers, especially with reference to the detachment mechanism. The bond response of old masonries could be very different from that occurring in new masonry units which are the ones generally considered in most of the bond tests available in technical literature. The aim of the present paper is the study of the bond behavior of historical clay bricks strengthened with steel reinforced polymers (SRP) materials. In particular, the results of an experimental study concerning new manufactured clay bricks and old bricks extracted from different historical masonry buildings are presented. The obtained results, particularly in terms of bond resistance, detachment mechanism and strain distributions, are discussed for the purpose of analyzing the peculiarities of the historical bricks in comparison with new manufactured ones. Some considerations on the efficacy of the theoretical formulations of the recent Italian code are also carried out.

  15. Effects of machining conditions on the specific cutting energy of carbon fibre reinforced polymer composites

    Science.gov (United States)

    Azmi, A. I.; Syahmi, A. Z.; Naquib, M.; Lih, T. C.; Mansor, A. F.; Khalil, A. N. M.

    2017-10-01

    This article presents an approach to evaluate the effects of different machining conditions on the specific cutting energy of carbon fibre reinforced polymer composites (CFRP). Although research works in the machinability of CFRP composites have been very substantial, the present literature rarely discussed the topic of energy consumption and the specific cutting energy. A series of turning experiments were carried out on two different CFRP composites in order to determine the power and specific energy constants and eventually evaluate their effects due to the changes in machining conditions. A good agreement between the power and material removal rate using a simple linear relationship. Further analyses revealed that a power law function is best to describe the effect of feed rate on the changes in the specific cutting energy. At lower feed rate, the specific cutting energy increases exponentially due to the nature of finishing operation, whereas at higher feed rate, the changes in specific cutting energy is minimal due to the nature of roughing operation.

  16. Shear Strengthening of RC Beams Using Sprayed Glass Fiber Reinforced Polymer

    Directory of Open Access Journals (Sweden)

    Sayed Mohamad Soleimani

    2012-01-01

    Full Text Available The effectiveness of externally bonded sprayed glass fiber reinforced polymer (Sprayed GFRP in shear strengthening of RC beams under quasi-static loading is investigated. Different techniques were utilized to enhance the bond between concrete and Sprayed GFRP, involving the use of through bolts and nuts paired with concrete surface preparation through sandblasting and through the use of a pneumatic chisel prior to Sprayed GFRP application. It was found that roughening the concrete surface using a pneumatic chisel and using through bolts and nuts were the most effective techniques. Also, Sprayed GFRP applied on 3 sides (U-shaped was found to be more effective than 2-sided Sprayed GFRP in shear strengthening. Sprayed GFRP increased the shear load-carrying capacity and energy absorption capacities of RC beams. It was found that the load-carrying capacity of strengthened RC beams was related to an effective strain of applied Sprayed GFRP. This strain was related to Sprayed GFRP configuration and the technique used to enhance the concrete-FRP bond. Finally, an equation was proposed to calculate the contribution of Sprayed GFRP in the shear strength of an RC beam.

  17. Parametric Study on Dynamic Response of Fiber Reinforced Polymer Composite Bridges

    Directory of Open Access Journals (Sweden)

    Woraphot Prachasaree

    2015-01-01

    Full Text Available Because of high strength and stiffness to low self-weight ratio and ease of field installation, fiber reinforced polymer (FRP composite materials are gaining popularity as the materials of choice to replace deteriorated concrete bridge decks. FRP bridge deck systems with lower damping compared to conventional bridge decks can lead to higher amplitudes of vibration causing dynamically active bridge deck leading serviceability problems. The FRP bridge models with different bridge configurations and loading patterns were simulated using finite element method. The dynamic response results under varying FRP deck system parameters were discussed and compared with standard specifications of bridge deck designs under dynamic loads. In addition, the dynamic load allowance equation as a function of natural frequency, span length, and vehicle speed was proposed in this study. The proposed dynamic load allowance related to the first flexural frequency was presented herein. The upper and lower bounds’ limits were established to provide design guidance in selecting suitable dynamic load allowance for FRP bridge systems.

  18. Detection of Bond Defects in Carbon Fiber Reinforced Polymer Strengthened Concrete Using Pulse Phase Thermography

    Science.gov (United States)

    Mabry, Nehemiah James

    As externally bonded fiber-reinforced polymers (FRP) are finding regular use in the strengthening of existing concrete structures, common installation practices still allow for the likelihood of defects forming at the interface of these bond-critical systems. Though published guidelines exist to provide recommendations for handling this issue in the field, significant research is still needed to determine critical defects, their identification using rapid methods of nondestructive evaluation (NDE) techniques, and the effect of such defects on the overall performance. This dissertation examines the use of pulsed phase infrared thermography (PPT) as a method to determine the location, size and depth of bond defects in wet lay-up carbon FRP (CFRP) systems. A series of small scale, single lap shear pull-tests were also performed to examine the effect detectable defects have on the strength of the CFRP strengthened concrete joints. Environmental conditioning protocols, namely submersion and freeze-thaw cycles, were also subjected to a subsample of specimens in order to observe durability effects on ultimate loads and strains. Results from PPT inspection and structural tests were then compared to present an effective approach for monitoring and evaluation. Finally a set of conclusions were presented regarding PPT inspection and the criticality of defects found in CFRP strengthened concrete governed by the common debonding mechanism.

  19. Failure of a carbon fiber-reinforced polymer implant used for transforaminal lumbar interbody fusion.

    Science.gov (United States)

    Sardar, Zeeshan; Jarzem, Peter

    2013-12-01

    Lumbar interbody fusion is a common procedure owing to the high prevalence of degenerative spinal disorders. During such procedures, carbon fiber-reinforced polymer (CFRP) cages are frequently utilized to fill the void created between adjacent vertebral bodies, to provide mechanical stability, and to carry graft material. Failure of such implants can lead to significant morbidity. We discuss the possible causes leading to the failure of a CFRP cage in a patient with rheumatoid arthritis. Review of a 49-year-old woman who underwent revision anterior lumbar interbody fusion 2 years after posterior instrumentation and transforaminal lumbar interbody fusion at L4-L5 and L5-S1. The patient developed pseudarthrosis at the two previously fused levels with failure of the posterior instrumentation. Revision surgery reveled failure with fragmentation of the CFRP cage at the L5-S1 level. CFRP implants can break if mechanical instability or nonunion occurs in the spinal segments, thus emphasizing the need for optimizing medical management and meticulous surgical technique in achieving stability.

  20. Self-monitoring fiber reinforced polymer strengthening system for civil engineering infrastructures

    Science.gov (United States)

    Jiang, Guoliang; Dawood, Mina; Peters, Kara; Rizkalla, Sami

    2008-03-01

    Fiber reinforced polymer (FRP) materials are currently used for strengthening civil engineering infrastructures. The strengthening system is dependant on the bond characteristics of the FRP to the external surface of the structure to be effective in resisting the applied loads. This paper presents an innovative self-monitoring FRP strengthening system. The system consists of two components which can be embedded in FRP materials to monitor the global and local behavior of the strengthened structure respectively. The first component of the system is designed to evaluate the applied load acting on a structure based on elongation of the FRP layer along the entire span of the structure. Success of the global system has been demonstrated using a full-scale prestressed concrete bridge girder which was loaded up to failure. The test results indicate that this type of sensor can be used to accurately determine the load prior to failure within 15 percent of the measured value. The second sensor component consists of fiber Bragg grating sensors. The sensors were used to monitor the behavior of steel double-lap shear splices tested under tensile loading up to failure. The measurements were used to identify abnormal structural behavior such as epoxy cracking and FRP debonding. Test results were also compared to numerical values obtained from a three dimensional shear-lag model which was developed to predict the sensor response.

  1. Shear Strength of Unreinforced Masonry Wall Retrofitted with Fiber Reinforced Polymer and Hybrid Sheet

    Directory of Open Access Journals (Sweden)

    Yun-Cheul Choi

    2015-01-01

    Full Text Available Unreinforced masonry (URM structures represent a significant portion of existing historical structures around the world. Recent earthquakes have shown the need for seismic retrofitting for URM structures. Various types of strengthening methods have been used for URM structures. In particular, a strengthening technique using externally bonded (EB fiber reinforced polymer (FRP composites has attracted engineers since EB FRP materials effectively enhance the shear strength of URM walls with negligible change to cross-sectional area and weight of the walls. Research has been extensively conducted to determine characteristics of URM walls strengthened with EB FRP materials. However, it is still difficult to determine an appropriate retrofitting level due to the complexity of mechanical behavior of strengthened URM walls. In this study, in-plane behavior under lateral loading was, therefore, investigated on a full-scale nonstrengthened URM wall and URM walls retrofitted with two different FRP materials: carbon (CFRP and hybrid (HFRP sheets. The test results indicated that both FRP composites were effective in increasing shear strength in comparison with the control specimen. However, better performance was obtained with HFRP compared to CFRP. In addition, an equation for estimating effective strain was proposed, and the theoretical results were in good agreement with the experimental ones.

  2. Glass Fiber Reinforced Polymer (GFRP Bars for Enhancing the Flexural Performance of RC Beams Using Side-NSM Technique

    Directory of Open Access Journals (Sweden)

    Md. Akter Hosen

    2017-05-01

    Full Text Available Reinforced concrete (RC structures require strengthening for numerous factors, such as increased load, modification of the structural systems, structural upgrade or errors in the design and construction stages. The side near-surface mounted (SNSM strengthening technique with glass fiber-reinforced polymer (GFRP bars is a relatively new emerging technique for enhancing the flexural capacities of existing RC elements. Nine RC rectangular beams were flexurally strengthened with this technique and tested under four-point bending loads until failure. The main goal of this study is to optimize the structural capacity of the RC beams by varying the amount of strengthening reinforcement and bond length. The experimental test results showed that strengthening with SNSM GFRP bars significantly enhanced the flexural responses of the specimens compared with the control specimen. The first cracking and ultimate loads, energy absorption capacities, ductility and stiffness were remarkably enhanced by the SNSM technique. It was also confirmed that the bond length of the strengthened reinforcement greatly influences the energy absorption capacities, ductility and stiffness. The effect of the bond length on these properties is more significant compared to the amount of strengthening reinforcement.

  3. Surface characterization of carbon fiber reinforced polymers by picosecond laser induced breakdown spectroscopy

    Science.gov (United States)

    Ledesma, Rodolfo; Palmieri, Frank; Connell, John; Yost, William; Fitz-Gerald, James

    2018-02-01

    Adhesive bonding of composite materials requires reliable monitoring and detection of surface contaminants as part of a vigorous quality control process to assure robust and durable bonded structures. Surface treatment and effective monitoring prior to bonding are essential in order to obtain a surface which is free from contaminants that may lead to inferior bond quality. In this study, the focus is to advance the laser induced breakdown spectroscopy (LIBS) technique by using pulse energies below 100 μJ (μLIBS) for the detection of low levels of silicone contaminants in carbon fiber reinforced polymer (CFRP) composites. Various CFRP surface conditions were investigated by LIBS using ∼10 ps, 355 nm laser pulses with pulse energies below 30 μJ. Time-resolved analysis was conducted to optimize the gate delay and gate width for the detection of the C I emission line at 247.9 nm to monitor the epoxy resin matrix of CFRP composites and the Si I emission line at 288.2 nm for detection of silicone contaminants in CFRP. To study the surface sensitivity to silicone contamination, CFRP surfaces were coated with polydimethylsiloxane (PDMS), the active ingredient in many mold release agents. The presence of PDMS was studied by inspecting the Si I emission lines at 251.6 nm and 288.2 nm. The measured PDMS areal densities ranged from 0.15 to 2 μg/cm2. LIBS measurements were performed before and after laser surface ablation. The results demonstrate the successful detection of PDMS thin layers on CFRP using picosecond μLIBS.

  4. Exposure Assessment of a High-energy Tensile Test With Large Carbon Fiber Reinforced Polymer Cables.

    Science.gov (United States)

    Schlagenhauf, Lukas; Kuo, Yu-Ying; Michel, Silvain; Terrasi, Giovanni; Wang, Jing

    2015-01-01

    This study investigated the particle and fiber release from two carbon fiber reinforced polymer cables that underwent high-energy tensile tests until rupture. The failing event was the source of a large amount of dust whereof a part was suspected to be containing possibly respirable fibers that could cause adverse health effects. The released fibers were suspected to migrate through small openings to the experiment control room and also to an adjacent machine hall where workers were active. To investigate the fiber release and exposure risk of the affected workers, the generated particles were measured with aerosol devices to obtain the particle size and particle concentrations. Furthermore, particles were collected on filter samples to investigate the particle shape and the fiber concentration. Three situations were monitored for the control room and the machine hall: the background concentrations, the impact of the cable failure, and the venting of the exposed rooms afterward. The results showed four important findings: The cable failure caused the release of respirable fibers with diameters below 3 μm and an average length of 13.9 μm; the released particles did migrate to the control room and to the machine hall; the measured peak fiber concentration of 0.76 fibers/cm(3) and the overall fiber concentration of 0.07 fibers/cm(3) in the control room were below the Permissible Exposure Limit (PEL) for fibers without indication of carcinogenicity; and the venting of the rooms was fast and effective. Even though respirable fibers were released, the low fiber concentration and effective venting indicated that the suspected health risks from the experiment on the affected workers was low. However, the effect of long-term exposure is not known therefore additional control measures are recommended.

  5. Nanostructured Carbon Nitride Polymer-Reinforced Electrolyte To Enable Dendrite-Suppressed Lithium Metal Batteries.

    Science.gov (United States)

    Hu, Jiulin; Tian, Jing; Li, Chilin

    2017-04-05

    Lithium metal batteries (LMBs) containing S, O2, and fluoride cathodes are attracting increasing attention owing to their much higher energy density than that of Li-ion batteries. However, current limitation for the progress of LMBs mainly comes from the uncontrolled formation and growth of Li dendrites at the anode side. In order to suppress dendrite growth, exploring novel nanostructured electrolyte of high modulus without degradation of Li-electrolyte interface appears to be a potential solution. Here we propose a lightweight polymer-reinforced electrolyte based on graphitic carbon nitride (g-C3N4) mesoporous microspheres as electrolyte filler [bis(trifluoromethanesulfonimide) lithium salt/di(ethylene glycol) dimethyl ether mixed with g-C3N4, denoted as LiTFSI-DGM-C3N4] for the first time. This nanostructured electrolyte can effectively suppress lithium dendrite growth during cycling, benefiting from the high mechanical strength and nanosheet-built hierarchical structure of g-C3N4. The Li/Li symmetrical cell based on this slurrylike electrolyte enables long-term cycling of at least 120 cycles with a high capacity of 6 mA·h/cm2 and small plating/stripping overpotential of ∼100 mV at a high current density of 2 mA/cm2. g-C3N4 filling also enables a separator(Celgard)-free Li/FeS2 cell with at least 400 cycles. The 3D geometry of g-C3N4 shows advantages on interfacial resistance and Li plating/stripping stability compared to its 2D geometry.

  6. Monoclinic hydroxyapatite.

    Science.gov (United States)

    Elliott, J C; Mackie, P E; Young, R A

    1973-06-08

    The existence of a monoclinic phase of hydroxyapatite, Ca(2)(PO(4))(4)OH, has been confirmed, by single-crystal structure analysis (weighted "reliability" factor = 3.9 percent on |F|(2)). The structure has space group P21/b, a = 9.4214(8) angstroms, b = 2a, c = 6.8814(7) angstroms, and gamma = 120 degrees , and is analogous to that of chlorapatite. The distortions from the hexagonal structure with which the monoclinic structure is pseudosymmetric are similar to those in chlorapatite, including enlargement of that triangular array of oxygen atoms in which the chlorine ion or, in hydroxyapatite, the hydroxyl hydrogen ion is approximately centered. The hydroxyapatite specimen was prepared by the conversion of a single crystal of chlorapatite in steam at 1200 degrees C, was mimetically twinned, and was approximately 37 percent monoclinic.

  7. Effect of Moisture Absorption Behavior on Mechanical Properties of Basalt Fibre Reinforced Polymer Matrix Composites

    OpenAIRE

    Amuthakkannan Pandian; Manikandan Vairavan; Winowlin Jappes Jebbas Thangaiah; Marimuthu Uthayakumar

    2014-01-01

    The study of mechanical properties of fibre reinforced polymeric materials under different environmental conditions is much important. This is because materials with superior ageing resistance can be satisfactorily durable. Moisture effects in fibre reinforced plastic composites have been widely studied. Basalt fibre reinforced unsaturated polyester resin composites were subjected to water immersion tests using both sea and normal water in order to study the effects of water absorption behavi...

  8. Time-frequency analysis of acoustic emission signals generated by the Glass Fibre Reinforced Polymer Composites during the tensile test

    Science.gov (United States)

    Świt, G.; Adamczak, A.; Krampikowska, A.

    2017-10-01

    Fibre reinforced polymer composites are currently dominating in the composite materials market. The lack of detailed knowledge about their properties and behaviour in various conditions of exposure under load significantly limits the broad possibilities of application of these materials. Occurring and accumulation of defects in material during the exploitation of the construction lead to the changes of its technical condition. The necessity to control the condition of the composite is therefore justified. For this purpose, non-destructive method of acoustic emission can be applied. This article presents an example of application of acoustic emission method based on time analysis and time-frequency analysis for the evaluation of the progress of the destructive processes and the level of degradation of glass fibre reinforced composite tapes that were subject to tensile testing.

  9. A review of the application Acoustic Emission (AE) incorporating mechanical approach to monitor Reinforced concrete (RC) strengthened with Fiber Reinforced Polymer (FRP) properties under fracture

    Science.gov (United States)

    Syed Mazlan, S. M. S.; Abdullah, S. R.; Shahidan, S.; Noor, S. R. Mohd

    2017-11-01

    Concrete durability may be affected by so many factors such as chemical attack and weathering action that reduce the performance and the service life of concrete structures. Low durability Reinforced concrete (RC) can be greatly improved by using Fiber Reinforce Polymer (FRP). FRP is a commonly used composite material for repairing and strengthening RC structures. A review on application of Acoustic Emission (AE) techniques of real time monitoring for various mechanical tests for RC strengthened with FRP involving four-point bending, three-point bending and cyclic loading was carried out and discussed in this paper. Correlations between each AE analyses namely b-value, sentry and intensity analysis on damage characterization also been critically reviewed. From the review, AE monitoring involving RC strengthened with FRP using b-value, sentry and intensity analysis are proven to be successful and efficient method in determining damage characterization. However, application of AE analysis using sentry analysis is still limited compared to b-value and intensity analysis in characterizing damages especially for RC strengthened with FRP specimen.

  10. The Impact of Methods of Forming on the Mechanical Properties of Fiber-reinforced Polymer-matrix Composite Materials

    Directory of Open Access Journals (Sweden)

    Piernik Krzysztof

    2015-11-01

    Full Text Available The aim of this paper was to analyze how different techniques of production of fibrous composite materials affect the quality and strength properties of composite laminates. In this study, we use experimental data concerning a composite fabricated with the by hand lay-up and vacuum bagging method. The composites have a polyester matrix (Firestop 8175-w-1 reinforced with mate-glass fiber fabric [0/90/0/90] E glass fiber, respectively. The process parameters and criteria were determined before the samples were cut, namely the amount and soaking time of the composite with the polymer resin.

  11. Electrical Resistance Based Damage Modeling of Multifunctional Carbon Fiber Reinforced Polymer Matrix Composites

    Science.gov (United States)

    Hart, Robert James

    In the current thesis, the 4-probe electrical resistance of carbon fiber-reinforced polymer (CFRP) composites is utilized as a metric for sensing low-velocity impact damage. A robust method has been developed for recovering the directionally dependent electrical resistivities using an experimental line-type 4-probe resistance method. Next, the concept of effective conducting thickness was uniquely applied in the development of a brand new point-type 4-probe method for applications with electrically anisotropic materials. An extensive experimental study was completed to characterize the 4-probe electrical resistance of CFRP specimens using both the traditional line-type and new point-type methods. Leveraging the concept of effective conducting thickness, a novel method was developed for building 4-probe electrical finite element (FE) models in COMSOL. The electrical models were validated against experimental resistance measurements and the FE models demonstrated predictive capabilities when applied to CFRP specimens with varying thickness and layup. These new models demonstrated a significant improvement in accuracy compared to previous literature and could provide a framework for future advancements in FE modeling of electrically anisotropic materials. FE models were then developed in ABAQUS for evaluating the influence of prescribed localized damage on the 4-probe resistance. Experimental data was compiled on the impact response of various CFRP laminates, and was used in the development of quasi- static FE models for predicting presence of impact-induced delamination. The simulation-based delamination predictions were then integrated into the electrical FE models for the purpose of studying the influence of realistic damage patterns on electrical resistance. When the size of the delamination damage was moderate compared to the electrode spacing, the electrical resistance increased by less than 1% due to the delamination damage. However, for a specimen with large

  12. Characterization of a carbon fiber reinforced polymer repair system for structurally deficient steel piping

    Science.gov (United States)

    Wilson, Jeffrey M.

    This Dissertation investigates a carbon fiber reinforced polymer repair system for structurally deficient steel piping. Numerous techniques exist for the repair of high-pressure steel piping. One repair technology that is widely gaining acceptance is composite over-wraps. Thermal analytical evaluations of the epoxy matrix material produced glass transition temperature results, a cure kinetic model, and a workability chart. These results indicate a maximum glass transition temperature of 80°C (176°F) when cured in ambient conditions. Post-curing the epoxy, however, resulted in higher glass-transition temperatures. The accuracy of cure kinetic model presented is temperature dependent; its accuracy improves with increased cure temperatures. Cathodic disbondment evaluations of the composite over-wrap show the epoxy does not breakdown when subjected to a constant voltage of -1.5V and the epoxy does not allow corrosion to form under the wrap from permeation. Combustion analysis of the composite over-wrap system revealed the epoxy is flammable when in direct contact with fire. To prevent combustion, an intumescent coating was developed to be applied on the composite over-wrap. Results indicate that damaged pipes repaired with the carbon fiber composite over-wrap withstand substantially higher static pressures and exhibit better fatigue characteristics than pipes lacking repair. For loss up to 80 percent of the original pipe wall thickness, the composite over-wrap achieved failure pressures above the pipe's specified minimum yield stress during monotonic evaluations and reached the pipe's practical fatigue limit during cyclical pressure testing. Numerous repairs were made to circular, thru-wall defects and monotonic pressure tests revealed containment up to the pipe's specified minimum yield strength for small diameter defects. The energy release rate of the composite over-wrap/steel interface was obtained from these full-scale, leaking pipe evaluations and results

  13. Three-dimensional smoothed particle hydrodynamics simulation for injection molding flow of short fiber-reinforced polymer composites

    Science.gov (United States)

    He, Liping; Lu, Gang; Chen, Dachuan; Li, Wenjun; Lu, Chunsheng

    2017-07-01

    This paper investigates the three-dimensional (3D) injection molding flow of short fiber-reinforced polymer composites using a smoothed particle hydrodynamics (SPH) simulation method. The polymer melt was modeled as a power law fluid and the fibers were considered as rigid cylindrical bodies. The filling details and fiber orientation in the injection-molding process were studied. The results indicated that the SPH method could effectively predict the order of filling, fiber accumulation, and heterogeneous distribution of fibers. The SPH simulation also showed that fibers were mainly aligned to the flow direction in the skin layer and inclined to the flow direction in the core layer. Additionally, the fiber-orientation state in the simulation was quantitatively analyzed and found to be consistent with the results calculated by conventional tensor methods.

  14. Recycling high-performance carbon fiber reinforced polymer composites using sub-critical and supercritical water

    Science.gov (United States)

    Knight, Chase C.

    Carbon fiber reinforced plastics (CFRP) are composite materials that consist of carbon fibers embedded in a polymer matrix, a combination that yields materials with properties exceeding the individual properties of each component. CFRP have several advantages over metals: they offer superior strength to weight ratios and superior resistance to corrosion and chemical attack. These advantages, along with continuing improvement in manufacturing processes, have resulted in rapid growth in the number of CFRP products and applications especially in the aerospace/aviation, wind energy, automotive, and sporting goods industries. Due to theses well-documented benefits and advancements in manufacturing capabilities, CFRP will continue to replace traditional materials of construction throughout several industries. However, some of the same properties that make CFRP outstanding materials also pose a major problem once these materials reach the end of service life. They become difficult to recycle. With composite consumption in North America growing by almost 5 times the rate of the US GDP in 2012, this lack of recyclability is a growing concern. As consumption increases, more waste will inevitably be generated. Current composite recycling technologies include mechanical recycling, thermal processing, and chemical processing. The major challenge of CFRP recycling is the ability to recover materials of high-value and preserve their properties. To this end, the most suitable technology is chemical processing, where the polymer matrix can be broken down and removed from the fiber, with limited damage to the fibers. This can be achieved using high concentration acids, but such a process is undesirable due to the toxicity of such materials. A viable alternative to acid is water in the sub-critical and supercritical region. Under these conditions, the behavior of this abundant and most environmentally friendly solvent resembles that of an organic compound, facilitating the breakdown

  15. Double-Sided Terahertz Imaging of Multilayered Glass Fiber-Reinforced Polymer

    National Research Council Canada - National Science Library

    Przemyslaw Lopato

    2017-01-01

    Polymer matrix composites (PMC) play important roles in modern industry. Increasing the number of such structures in aerospace, construction, and automotive applications enforces continuous monitoring of their condition...

  16. CNT-based Reinforcing Polymer Matrix Composites for Lightweight Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Carbon Polymer Matrix Composites (PMCs) are attractive structural materials for NASA applications due to their high strength to weight ratio, mechanical properties...

  17. Polyurethane foam infill for fiber-reinforced polymer (FRP) bridge deck panels.

    Science.gov (United States)

    2014-05-01

    The objective of the proposed research is to develop, test, and evaluate fiber-reinforced, polyurethane foams to replace the costly : honeycomb construction currently used to manufacture FRP bridge deck panels. The effort will focus on developing an ...

  18. Development and performance evaluation of fiber reinforced polymer bridge : [technical summary].

    Science.gov (United States)

    2014-03-01

    Conventionally, highway bridge decks in the US are predominantly made of steel-reinforced concrete. However, repair and : maintenance costs of these bridges incurred at the federal and state levels are overwhelming. As a result, for many years, there...

  19. Geometrical Effect on Thermal Conductivity of Unidirectional Fiber-Reinforced Polymer Composite along Different In-plane Orientations

    Science.gov (United States)

    Fang, Zenong; Li, Min; Wang, Shaokai; Li, Yanxia; Wang, Xiaolei; Gu, Yizhuo; Liu, Qianli; Tian, Jie; Zhang, Zuoguang

    2017-11-01

    This paper focuses on the anisotropic characteristics of the in-plane thermal conductivity of fiber-reinforced polymer composite based on experiment and simulation. Thermal conductivity along different in-plane orientations was measured by laser flash analysis (LFA) and steady-state heat flow method. Their heat transfer processes were simulated to reveal the geometrical effect on thermal conduction. The results show that the in-plane thermal conduction of unidirectional carbon-fiber-reinforced polymer composite is greatly influenced by the sample geometry at an in-plane orientation angle between 0° to 90°. By defining radius-to-thickness as a dimensionless shape factor for the LFA sample, the apparent thermal conductivity shows a dramatic change when the shape factor is close to the tangent of the orientation angle (tanθ). Based on finite element analysis, this phenomenon was revealed to correlate with the change of the heat transfer process. When the shape factor is larger than tanθ, the apparent thermal conductivity is consistent with the estimated value according to the theoretical model. For a sample with a shape factor smaller than tanθ, the apparent thermal conductivity shows a slow growth around a low value, which seriously deviates from the theory estimation. This phenomenon was revealed to correlate with the change of the heat transfer process from a continuous path to a zigzag path. These results will be helpful in optimizing the ply scheme of composite laminates for thermal management applications.

  20. Strengthening of concrete structures using carbon fibre reinforced polymers and cement-based adhesives

    OpenAIRE

    Hashemi, Siavash

    2017-01-01

    The research project conducted in this study concerns the investigation of the application of cement-based adhesives in CFRP strengthening of reinforced concrete members. The results demonstrate that mineral-based adhesives can provide the desired matrices for CFRP reinforcement. The literature review covers the background of CFRP application with conventional techniques. The bond characteristics of CFRP to concrete substrate, the flexural performance of retrofitted RC beams, and the fa...

  1. Dispersion and Reinforcement of Nanotubes in High Temperature Polymers for Ultrahigh Strength and Thermally Conductive Nanocomposites

    Science.gov (United States)

    2007-10-03

    System PBO are a class of heterocyclic polymers of excellent thermal stability with the decompose temperature Td around 650C. The Young’s modulus is...substitute HBr to form vinyl polymer. From FTIR shown in Figure34, we observe that around 880~950 cm-1 there is a peak of absorption. This represents

  2. RETROVIT KOLOM PENDEK BETON BERTULANG PERSEGI DENGAN PERKUATAN EKSTERNAL CARBON FIBER-REINFORCED POLYMER DI BAWAH PENGARUH PEMBEBANAN SIKLIK

    Directory of Open Access Journals (Sweden)

    Agus Sulistiawan

    2014-01-01

    Full Text Available The retrofit of non-slender square concrete column with an external strength­ener of carbon fiber-reinforced polymer (CFRP under the influence of cyclic load. The purpose of this study is to know the increase of strength and ductility of a column structure element that has an initial damage, then it is fixed and strengthened by CFRP external strengthening. The column structure element is tested by giving a constant axial load and varying the cyclic load using a displacement control. In this research, two specimens t are used, C-1 column (original column and C-1RC column (retrofit column. The results of the study show that (1 the effectiveness of the C-1CR’s restraint and moment of force are increased by 1.58 times and 52.78% compared to the C-1’s ones, and (2 the installation of CFRP reinforcement increases the strength in accepting lateral load by 52.15% and decreases of ductility by 52.12%.   Tujuan penelitian ini mengetahui peningkatan kekuatan dan daktilitas ele­men struktur kolom yang mengalami kerusakan awal, kemudian diperbaiki, dan diperkuat dengan perkuatan eksternal carbon fiber-reinforced polymer (CFRP. Pengujian ter­hadap elemen struktur kolom dilakukan dengan memberikan beban aksial yang konstan dan memvariasikan beban siklik dengan kontrol perpindahan. Dalam penelitian ini digunakan dua spesimen yaitu kolom C-1 (kolom original dan kolom C-1RC (kolom retrofit. Hasil penelitian menunjukkan (1 efektifitas pengekangan C-1CR meningkat 1,58 kali dan kekuatan terhadap momen meningkat sebesar 52,78% dibanding kolom C-1, dan (2  pemasangan perkuatan CFRP memberikan peningkatan kekuatan dalam menerima beban lateral sebesar 52,15% dan penurunan daktilitas sebesar -52,12%.

  3. Mechanical analysis of carbon fiber reinforced shape memory polymer composite for self-deployable structure in space environment

    Science.gov (United States)

    Hong, Seok Bin; Ahn, Yong San; Jang, Joon Hyeok; Kim, Jin-Gyun; Goo, Nam Seo; Yu, Woong-Ryeol

    2016-04-01

    Shape memory polymer (SMP) is one of smart polymers which exhibit shape memory effect upon external stimuli. Reinforcements as carbon fiber had been used for making shape memory polymer composite (CF-SMPC). This study investigated a possibility of designing self-deployable structures in harsh space condition using CF-SMPCs and analyzed their shape memory behaviors with constitutive equation model.CF-SMPCs were prepared using woven carbon fabrics and a thermoset epoxy based SMP to obtain their basic mechanical properties including actuation in harsh environment. The mechanical and shape memory properties of SMP and CF-SMPCs were characterized using dynamic mechanical analysis (DMA) and universal tensile machine (UTM) with an environmental chamber. The mechanical properties such as flexural strength and tensile strength of SMP and CF-SMPC were measured with simple tensile/bending test and time dependent shape memory behavior was characterized with designed shape memory bending test. For mechanical analysis of CF-SMPCs, a 3D constitutive equation of SMP, which had been developed using multiplicative decomposition of the deformation gradient and shape memory strains, was used with material parameters determined from CF-SMPCs. Carbon fibers in composites reinforced tensile and flexural strength of SMP and acted as strong elastic springs in rheology based equation models. The actuation behavior of SMP matrix and CF-SMPCs was then simulated as 3D shape memory bending cases. Fiber bundle property was imbued with shell model for more precise analysis and it would be used for prediction of deploying behavior in self-deployable hinge structure.

  4. Retrofitting Of RCC Piles By Using Basalt Fiber Reinforced Polymer BFRP Composite Part 1 Review Papers On RCC Structures And Piles Retrofitting Works.

    Directory of Open Access Journals (Sweden)

    R. Ananda Kumar

    2015-01-01

    Full Text Available Abstract Retrofitting works are immensely essential for deteriorated and damaged structures in Engineering and Medical fields in order to keep or return to the originality for safe guarding the structures and consumers. In this paper different types of methods of retrofitting review notes are given based on the experimental numerical and analytical methods results on strengthening the Reinforced cement concrete RCC structures including RCC piles. Soil-pile interaction on axial load lateral load reviews are also presented. This review paper is prepared to find out the performance of basalt fibre reinforced polymer BFRP composite retrofitted reinforced cement concrete single end bearing piles.

  5. Effect of monomer composition of polymer matrix on flexural properties of glass fibre-reinforced orthodontic archwire.

    Science.gov (United States)

    Ohtonen, J; Vallittu, P K; Lassila, L V J

    2013-02-01

    To compare force levels obtained from glass fibre-reinforced composite (FRC) archwires. Specifically, FRC wires were compared with polymer matrices having different dimethacrylate monomer compositions. FRC material (E-glass provided by Stick Tech Ltd, Turku, Finland) with continuous unidirectional glass fibres and four different types of dimethacrylate monomer compositions for the resin matrix were tested. Cross-sectionally round FRC archwires fitting into the 0.3 mm slot of a bracket were divided into 16 groups with six specimens in each group. Glass fibres were impregnated by the manufacturer, and they were initially light-cured by hand light-curing unit or additionally post-cured in light-curing oven. The FRC archwire specimens were tested at 37°C according to a three-point bending test in dry and wet conditions using a span length of 10 mm and a crosshead speed of 1.0 mm/minute. The wires were loaded until final failure. The data were statistically analysed using analysis of variance (ANOVA). The dry FRC archwire specimens revealed higher load values than water stored ones, regardless of the polymer matrix. A majority of the FRC archwires showed higher load values after being post-cured. ANOVA revealed that the polymer matrix, curing method, and water storage had a significant effect (P composition, curing method, and water storage affected the flexural properties and thus, force level and working range which could be obtained from the FRC archwire.

  6. Synthetic Effect of Vivid Shark Skin and Polymer Additive on Drag Reduction Reinforcement

    Directory of Open Access Journals (Sweden)

    Huawei Chen

    2014-06-01

    Full Text Available Natural shark skin has a well-demonstrated drag reduction function, which is mainly owing to its microscopic structure and mucus on the body surface. In order to improve drag reduction, it is necessary to integrate microscopic drag reduction structure and drag reduction agent. In this study, two hybrid approaches to synthetically combine vivid shark skin and polymer additive, namely, long-chain grafting and controllable polymer diffusion, were proposed and attempted to mimic such hierarchical topography of shark skin without waste of polymer additive. Grafting mechanism and optimization of diffusion port were investigated to improve the efficiency of the polymer additive. Superior drag reduction effects were validated, and the combined effect was also clarified through comparison between drag reduction experiments.

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

    Directory of Open Access Journals (Sweden)

    Bakri Bakri

    2017-03-01

    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

  8. Effect of Moisture Absorption Behavior on Mechanical Properties of Basalt Fibre Reinforced Polymer Matrix Composites

    Directory of Open Access Journals (Sweden)

    Amuthakkannan Pandian

    2014-01-01

    Full Text Available The study of mechanical properties of fibre reinforced polymeric materials under different environmental conditions is much important. This is because materials with superior ageing resistance can be satisfactorily durable. Moisture effects in fibre reinforced plastic composites have been widely studied. Basalt fibre reinforced unsaturated polyester resin composites were subjected to water immersion tests using both sea and normal water in order to study the effects of water absorption behavior on mechanical properties. Composites specimens containing woven basalt, short basalt, and alkaline and acid treated basalt fibres were prepared. Water absorption tests were conducted by immersing specimens in water at room temperature for different time periods till they reached their saturation state. The tensile, flexural, and impact properties of water immersed specimens were conducted and compared with dry specimens as per the ASTM standard. It is concluded that the water uptake of basalt fibre is considerable loss in the mechanical properties of the composites.

  9. 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.

  10. Thermo-oxidative stability studies of PMR-15 polymer matrix composites reinforced with various continuous fibers

    Science.gov (United States)

    Bowles, Kenneth J.

    1990-01-01

    An experimental study was conducted to measure the thermooxidative stability of PMR-15 composites reinforced with various fibers and to observe differences in the way they degrade in air. The fibers studied include graphite and the thermally stable Nicalon and Nextel ceramic fibers. Weight-loss rates for the different composites were assessed as a function of mechanical properties, specimen geometry, fiber sizing, and interfacial bond strength. Differences were observed in rates of weight loss, matrix cracking, geometry dependency, and fiber sizing effects. It was shown that Celion 6000 fiber-reinforced composites do not exhibit a straight-line Arrhenius relationship at temperatures above 316 C.

  11. Research on Sliding Wear Behavior of TiO2 Filled Glass Fiber Reinforced Polymer Composite

    OpenAIRE

    S. Srinivasa Moorthy; K. Manonmani

    2014-01-01

    In this study, Titanium Oxide (TiO2) particulate filled e-glass fiber reinforced composites in the unsaturated polyester resin matrix were prepared and its dry sliding wear behavior was optimized. Composites of varying fiber lengths of 1, 2 and 3 cm, respectively with different fiber content of 30, 40 and 50 wt. %, respectively were made. The particulate was varied with 2, 5 and 9 wt. %, respectively. The hybrid reinforced composites were prepared by hand layup method and the wear was measure...

  12. PENGGUNAAN CARBON FIBER-REINFORCED POLYMER SEBAGAI PERKUATAN KOLOM BETON BERTULANG AKIBAT BEBAN SIKLIK UNTUK MENINGKATKAN DAKTILITAS PERPINDAHAN STRUKTUR

    Directory of Open Access Journals (Sweden)

    Karmila Achmad

    2014-01-01

    Full Text Available The use of carbon fiber-reinforced polymer (CFRP as a concrete column re­inforcement in order to improve the structure displacement ductility caused by a cyclic load. The aim of this research is to improve the displacement ductility of a column specimen by giving CFRP strengthener (Carbon Fiber Reinforced Polymer. Two full-scale specimens are used, C-1 (original column and C-1C (column with CFRP strengthener 1 layer. The tests on C-1 and C-1C are respectively shown on the following results: Pmax is 278.9 kN and 432.2 kN, dmax is 53.24 mm and 96.46 mm, and Mmax is 328.04 kNm and 509.63 kNm. The displacement ductility of C-1 are 6.70, 6.11 and 5.44, and the displacement ductility of C-1C are 11.02, 12.75, and 11.89. The percentages of the increase of displacement ductility in column C-1C compared to C-1 are 64.48%, 108.74% and 118.68%  respectivelyfor plastic hinge zone, half high of the column effectiveness and as high as the column effectiveness.   Penelitian ini bertujuan untuk meningkatkan daktilitas perpindahan pada spe­simen kolom yang diberi perkuatan CFRP (Carbon Fiber Reinforced Polymer. Ada dua spesimen kolom skala penuh yang digunakan, yaitu C-1 (kolom original dan C-1C (kolom dengan perkuatan CFRP 1 lapis. Hasil penelitian untuk masing-masing C-1 dan C-1C adalah Pmax sebesar 278,9 kN dan 432,2 kN, dmax sebesar 53,24 mm dan 96,46 mm, serta Mmax sebesar 328,04 kNm dan 509,63 kNm. Hasil daktilitas perpindahan untuk C-1 adalah 6,70; 6,11 dan 5,44, sedang C-1C adalah 11,02; 12,75 dan 11,89. Peningkatan persentase daktilitas per­pindahan kolom C-1C terhadap C-1 adalah 64,48%, 108,74% dan 118,68% masing-masing untuk zona sendi plastis, setengah tinggi efektif kolom dan setinggi efektif kolom.

  13. Strain measurement in a concrete beam by use of the Brillouin-scattering-based distributed fiber sensor with single-mode fibers embedded in glass fiber reinforced polymer rods and bonded to steel reinforcing bars.

    Science.gov (United States)

    Zeng, Xiaodong; Bao, Xiaoyi; Chhoa, Chia Yee; Bremner, Theodore W; Brown, Anthony W; DeMerchant, Michael D; Ferrier, Graham; Kalamkarov, Alexander L; Georgiades, Anastasis V

    2002-08-20

    The strain measurement of a 1.65-m reinforced concrete beam by use of a distributed fiber strain sensor with a 50-cm spatial resolution and 5-cm readout resolution is reported. The strain-measurement accuracy is +/-15 microepsilon (microm/m) according to the system calibration in the laboratory environment with non-uniform-distributed strain and +/-5 microepsilon with uniform strain distribution. The strain distribution has been measured for one-point and two-point loading patterns for optical fibers embedded in pultruded glass fiber reinforced polymer (GFRP) rods and those bonded to steel reinforcing bars. In the one-point loading case, the strain deviations are +/-7 and +/-15 microepsilon for fibers embedded in the GFRP rods and fibers bonded to steel reinforcing bars, respectively, whereas the strain deviation is +/-20 microepsilon for the two-point loading case.

  14. The effect of polymer coated pumice to the stiffness and flexural strength of reinforce concrete beam

    Directory of Open Access Journals (Sweden)

    Wijatmiko Indradi

    2017-01-01

    Full Text Available Pumice has been proven as substitution material aggregate in lightweight aggregate concrete (LWAC. However due to its characteristic, pumice has the disadvantages of its excessive water absorption during preparation of concrete mixture which may reduce concrete strength. Therefore in order to eliminate this additional water absorption, this study investigate the effect of coated pumice in concrete mixture to the beam flexural strength and stiffness. This study performed flexural strength test on three types of sample: 1 normal reinforce concrete beam, 2 reinforce concrete beam with uncoated pumice and 3 reinforce concrete beam with coated pumice. The result showed that the lightest weight concrete occurred on the coated pumice specimen, with the reduction of water absorption was 4% compared to the uncoated pumice specimen. The stiffness of the reinforce beam with coated pumice was lower compared to the uncoated ones, this was due to the reduction of adhesion action between cement and aggregates. However, the use of coated pumice increased the flexural strength compare to the uncoated ones with 2.58%.

  15. Mineral-Ground Micro-Fibrillated Cellulose Reinforcement for Polymer Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, Jon [Fiberlean Technologies; Ireland, Sean [Fiberlean Technologies; Skuse, David [Imerys; Edwards, Martha [Imerys; Mclain, Leslie [Imerys; Tekinalp, Halil L [ORNL; Love, Lonnie J [ORNL; Kunc, Vlastimil [ORNL; Ozcan, Soydan [ORNL

    2017-01-01

    ORNL worked with Imerys to demonstrate reinforcement of additive manufacturing feedstock materials using mineral-ground microfibrillated cellulose (MFC). Properly prepared/dried mineral-ground cellulose microfibrils significantly improved mechanical properties of both ABS and PLA resins. While tensile strength increases up to ~40% were observed, elastic modulus of the both resins doubled with the addition of 30% MFC.

  16. Reinforcement effect of soy protein/carbohydrate ratio in styrene-butadiene polymer

    Science.gov (United States)

    Soy protein and carbohydrate at different ratios were blended with latex to form composites. The variation of protein to carbohydrate ratio has a sifnificant effect on the composite properties and the results from dynamic mechanical method showed a substantial reinforcement effect. The composites ...

  17. New Textile Sensors for In Situ Structural Health Monitoring of Textile Reinforced Thermoplastic Composites Based on the Conductive Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) Polymer Complex.

    Science.gov (United States)

    Jerkovic, Ivona; Koncar, Vladan; Grancaric, Ana Marija

    2017-10-10

    Many metallic structural and non-structural parts used in the transportation industry can be replaced by textile-reinforced composites. Composites made from a polymeric matrix and fibrous reinforcement have been increasingly studied during the last decade. On the other hand, the fast development of smart textile structures seems to be a very promising solution for in situ structural health monitoring of composite parts. In order to optimize composites' quality and their lifetime all the production steps have to be monitored in real time. Textile sensors embedded in the composite reinforcement and having the same mechanical properties as the yarns used to make the reinforcement exhibit actuating and sensing capabilities. This paper presents a new generation of textile fibrous sensors based on the conductive polymer complex poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) developed by an original roll to roll coating method. Conductive coating for yarn treatment was defined according to the preliminary study of percolation threshold of this polymer complex. The percolation threshold determination was based on conductive dry films' electrical properties analysis, in order to develop highly sensitive sensors. A novel laboratory equipment was designed and produced for yarn coating to ensure effective and equally distributed coating of electroconductive polymer without distortion of textile properties. The electromechanical properties of the textile fibrous sensors confirmed their suitability for in situ structural damages detection of textile reinforced thermoplastic composites in real time.

  18. New Textile Sensors for In Situ Structural Health Monitoring of Textile Reinforced Thermoplastic Composites Based on the Conductive Poly(3,4-ethylenedioxythiophene-poly(styrenesulfonate Polymer Complex

    Directory of Open Access Journals (Sweden)

    Ivona Jerkovic

    2017-10-01

    Full Text Available Many metallic structural and non-structural parts used in the transportation industry can be replaced by textile-reinforced composites. Composites made from a polymeric matrix and fibrous reinforcement have been increasingly studied during the last decade. On the other hand, the fast development of smart textile structures seems to be a very promising solution for in situ structural health monitoring of composite parts. In order to optimize composites’ quality and their lifetime all the production steps have to be monitored in real time. Textile sensors embedded in the composite reinforcement and having the same mechanical properties as the yarns used to make the reinforcement exhibit actuating and sensing capabilities. This paper presents a new generation of textile fibrous sensors based on the conductive polymer complex poly(3,4-ethylenedioxythiophene-poly(styrenesulfonate developed by an original roll to roll coating method. Conductive coating for yarn treatment was defined according to the preliminary study of percolation threshold of this polymer complex. The percolation threshold determination was based on conductive dry films’ electrical properties analysis, in order to develop highly sensitive sensors. A novel laboratory equipment was designed and produced for yarn coating to ensure effective and equally distributed coating of electroconductive polymer without distortion of textile properties. The electromechanical properties of the textile fibrous sensors confirmed their suitability for in situ structural damages detection of textile reinforced thermoplastic composites in real time.

  19. New Textile Sensors for In Situ Structural Health Monitoring of Textile Reinforced Thermoplastic Composites Based on the Conductive Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) Polymer Complex

    Science.gov (United States)

    Jerkovic, Ivona; Koncar, Vladan; Grancaric, Ana Marija

    2017-01-01

    Many metallic structural and non-structural parts used in the transportation industry can be replaced by textile-reinforced composites. Composites made from a polymeric matrix and fibrous reinforcement have been increasingly studied during the last decade. On the other hand, the fast development of smart textile structures seems to be a very promising solution for in situ structural health monitoring of composite parts. In order to optimize composites’ quality and their lifetime all the production steps have to be monitored in real time. Textile sensors embedded in the composite reinforcement and having the same mechanical properties as the yarns used to make the reinforcement exhibit actuating and sensing capabilities. This paper presents a new generation of textile fibrous sensors based on the conductive polymer complex poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) developed by an original roll to roll coating method. Conductive coating for yarn treatment was defined according to the preliminary study of percolation threshold of this polymer complex. The percolation threshold determination was based on conductive dry films’ electrical properties analysis, in order to develop highly sensitive sensors. A novel laboratory equipment was designed and produced for yarn coating to ensure effective and equally distributed coating of electroconductive polymer without distortion of textile properties. The electromechanical properties of the textile fibrous sensors confirmed their suitability for in situ structural damages detection of textile reinforced thermoplastic composites in real time. PMID:28994733

  20. Experimental Research Into the Effect Of External Actions and Polluting Environments on the Serviceablity of Fiber-Reinforced Polymer Composite Materials

    Science.gov (United States)

    Lobanov, D. S.; Vildeman, V. E.; Babin, A. D.; Grinev, M. A.

    2015-03-01

    The results of mechanical tests of fiberglass and CFRP specimens in transverse bending and interlaminar shear (the short-beam method) and of sandwich panels in tension and compression are presented. The effect of external polluting environments on the mechanical properties of fiber-reinforced polymer composite materials and structures is estimated. Stress-strain diagrams are constructed.

  1. A new system for posterior restorations: a combination of ceramic optimized polymer and fiber-reinforced composite.

    Science.gov (United States)

    Rosenthal, L; Trinkner, T; Pescatore, C

    1997-01-01

    Due to the need for increased strength characteristics and enhanced aesthetic expectations of the patients, metal-free, aesthetic restorative systems for the anterior and posterior dentition are currently available. A new "space-age" restorative material has been developed that is a combination of a ceramic optimized polymer (Ceromer) (Targis/Vectris, Ivoclar Williams, Amherst, NY) and a fiber-reinforced composite framework material. The purpose of this article is to discuss the qualities that render this material particularly suitable for a variety of indications, including laboratory-fabricated restorations for the stress-bearing posterior regions. The material lends itself to diversification. Its indication for inlays, onlays, full-coverage crown restorations, and conservative single pontic inlay bridges is presented.

  2. Fiber-Reinforced Polymer-Packaged Optical Fiber Bragg Grating Strain Sensors for Infrastructures under Harsh Environment

    Directory of Open Access Journals (Sweden)

    Zhi Zhou

    2016-01-01

    Full Text Available Optical fiber Bragg grating (FBG has been recognized as an outstanding high-performance local monitoring sensor and is largely applied in structural health monitoring (SHM. This paper proposes a series of fiber-reinforced polymer- (FRP- packaged optical fiber Bragg grating strain sensors to completely meet the requirements of rough civil engineering infrastructures, and their sensing performance under normal environment and harsh environment is experimentally investigated. It is experimentally and theoretically proved that FRP-packaged FBG strain sensors maintain excellent sensing performance as the bare FBG sensor under a harsh environment, and their durability is significantly enhanced due to the FRP materials. These FRP-packaged FBG strain sensors are successfully applied in the SHM system of Aizhai Bridge.

  3. Prestressing Effects on the Performance of Concrete Beams with Near-surface-mounted Carbon-fiber-reinforced Polymer Bars

    Science.gov (United States)

    Hong, Sungnam; Park, Sun-Kyu

    2016-07-01

    The effects of various prestressing levels on the flexural behavior of concrete beams strengthened with prestressed near-surface-mounted (NSM) carbon-fiber-reinforced polymer (CFRP) bars were investigated in this study. Four-point flexural tests up to failure were performed using a total of six strengthened prestressed and nonprestressed concrete beams. The nonprestressed strengthened beam failed by premature debonding at the interface of concrete and the epoxy adhesive, but the prestressed one failed owing due to rupture of the CFRP bar. As the prestressing level of the CFRP bar increased, the cracking and yield loads of the prestressed beams increased, but its effect on their deflections was insignificant. The ultimate load was constant regardless of prestressing level, but the ultimate deflection was almost inversely proportional to the level.

  4. Modified Johnston Failure Criterion from Rock Mechanics to Predict the Ultimate Strength of Fiber Reinforced Polymer (FRP Confined Columns

    Directory of Open Access Journals (Sweden)

    Zehra Canan Girgin

    2013-12-01

    Full Text Available The failure criteria from rock mechanics, Hoek-Brown and Johnston failure criteria, may be extended and modified to assess the ultimate compressive strength of axially loaded circular fiber reinforced polymer (FRP-confined concrete columns. In addition to the previously modified Hoek-Brown criterion, in this study, the Johnston failure criterion is extended to scope of FRP-confined concrete, verified with the experimental data and compared with the significant relationships from the current literature. Wide-range compressive strengths from 7 to 108 MPa and high confinement ratios up to 2.0 are used to verify the ultimate strengths in short columns. The results are in good agreement with experimental data for all confinement levels and concrete strengths.

  5. Applying CFD in Manufacturing of Polymer Composite Reinforced with Shape Memory Alloy via Resin Transfer Molding Process

    Directory of Open Access Journals (Sweden)

    S Silva

    2017-03-01

    Full Text Available This paper aims to study the manufacturing process of polymer composite reinforced with shape memory metal alloys by RTM process using ANSYS CFX® software. The mathematical modeling consists of mass and momentum conservation equations applied to a metal mold with dimensions 0.3 × 0.3 × 0.002 m³ containing ten NiTi alloy wires 0.0005 m diameter. Results of the flow front position of the resin (polyester resin mixed with calcium carbonate particles, pressure, streamlines and resin velocity fields during the process are presented and discussed. We conclude that the addition of calcium carbonate resulted in increased resin viscosity and greater inlet pressure obtained at the entrance of the mold which resulted in short time to full fill the mold and the highest pressures at the NiTi alloy wire surface were obtained in the central region and near the mold entrance.

  6. Waste Materials from Tetra Pak Packages as Reinforcement of Polymer Concrete

    Directory of Open Access Journals (Sweden)

    Miguel Martínez-López

    2015-01-01

    Full Text Available Different concentrations (from 1 to 6 wt% and sizes (0.85, 1.40, and 2.36 mm of waste Tetra Pak particles replaced partially silica sand in polymer concrete. As is well known, Tetra Pak packages are made up of three raw materials: cellulose (75%, low density polyethylene (20%, and aluminum (5%. The polymer concrete specimens were elaborated with unsaturated polyester resin (20% and silica sand (80% and irradiated by using gamma rays at 100 and 200 kGy. The obtained results have shown that compressive and flexural strength and modulus of elasticity decrease gradually, when either Tetra Pak particle concentration or particle size is increased, as regularly occurs in composite materials. Nevertheless, improvements of 14% on both compressive strength and flexural strength as well as 5% for modulus of elasticity were obtained when polymer concrete is irradiated.

  7. Waste Materials from Tetra Pak Packages as Reinforcement of Polymer Concrete

    OpenAIRE

    Miguel Martínez-López; Gonzalo Martínez-Barrera; Carlos Barrera-Díaz; Fernando Ureña-Núñez; Witold Brostow

    2015-01-01

    Different concentrations (from 1 to 6 wt%) and sizes (0.85, 1.40, and 2.36 mm) of waste Tetra Pak particles replaced partially silica sand in polymer concrete. As is well known, Tetra Pak packages are made up of three raw materials: cellulose (75%), low density polyethylene (20%), and aluminum (5%). The polymer concrete specimens were elaborated with unsaturated polyester resin (20%) and silica sand (80%) and irradiated by using gamma rays at 100 and 200 kGy. The obtained results have shown t...

  8. Short glass fiber-reinforced composite with a semi-interpenetrating polymer network matrix for temporary crowns and bridges.

    Science.gov (United States)

    Garoushi, Sufyan K; Vallittu, Pekka K; Lassila, Lippo V J

    2008-01-01

    The purpose of this study was to investigate the reinforcement effect of short E-glass fiber fillers on some mechanical properties of temporary crown and bridge (TCB) composite resin with a semi-interpenetrating polymer network (semi-IPN). Experimental temporary fiber reinforced (TFC) composite resin was prepared by mixing 15 wt% of short E-glass fibers (3 mm in length) with a 35 wt% of semi-IPN-resin (dual or chemical cure) with 50 wt% of silane treated particulate silica fillers using a high speed mixing device. Temporary crowns (n=6) and test specimens (2 x 2 x 25 mm3) (n=6) were made from the experimental TFC and conventional TCB composite (control, Protemp Garant, 3M-ESPE, St. Paul, MN, USA). A three-point bending test was done according to ISO standard 10477, and a compression loading test was carried out using a steel ball (Ø 3.0 mm) with a speed of 1.0 mm/min until fracture occurred. The degree of monomer conversion (DC%) of both composites was determined by Fourier transfer infrared (FTIR) spectrometry. The analysis of variance (ANOVA) revealed both dual and chemical cure experimental TFC composite resins had statistically significant (p<0.05) higher flexural strengths (117 and 99 MPa, respectively) and compressive load-bearing capacity (730 and 623 N, respectively) compared to the control TCB composite resin (72 MPa, 549 N). The use of short fiber fillers with semi-IPN polymer matrix yielded an improved mechanical performance compared to a conventional TCB composite resin.

  9. Hydroxyapatite for keratoprosthesis biointegration.

    Science.gov (United States)

    Wang, Liqiang; Jeong, Kyung Jae; Chiang, Homer H; Zurakowski, David; Behlau, Irmgard; Chodosh, James; Dohlman, Claes H; Langer, Robert; Kohane, Daniel S

    2011-09-22

    Integration of keratoprosthesis with the surrounding cornea is very important in preventing bacterial invasion, which may cause ocular injury. Here the authors investigated whether hydroxyapatite (HAp) coating can improve keratoprosthesis (KPro) biointegration, using polymethyl methacrylate (PMMA)--the principal component of the Boston KPro--as a model polymer. HAp coatings were induced on PMMA discs after treatment with concentrated NaOH and coating with poly-dopamine (PDA) or polydopamine and then with 11-mercaptoundecanoic acid (11-MUA). Coatings were characterized chemically (Fourier transform infrared spectroscopy [FTIR], energy dispersive X-ray spectroscopy [EDX]) and morphologically (SEM) and were used as substrates for keratocyte growth in vitro. Cylinders of coated PMMA were implanted in porcine corneas ex vivo for 2 weeks, and the force required to pull them out was measured. The inflammatory reaction to coated discs was assessed in the rabbit cornea in vivo. FTIR of the coatings showed absorption bands characteristic of phosphate groups, and EDX showed that the Ca/P ratios were close to those of HAp. By SEM, each method resulted in morphologically distinct HAp films; the 11-MUA group had the most uniform coating. The hydroxyapatite coatings caused comparable enhancement of keratocyte proliferation compared with unmodified PMMA surfaces. HAp coating significantly increased the force and work required to pull PMMA cylinders out of porcine corneas ex vivo. HAp coating of implants reduced the inflammatory response around the PMMA implants in vivo. These results are encouraging for the potential of HAp-coated surfaces for use in keratoprostheses.

  10. Novel meloxicam releasing electrospun polymer/ceramic reinforced biodegradable membranes for periodontal regeneration applications

    Energy Technology Data Exchange (ETDEWEB)

    Yar, Muhammad, E-mail: drmyar@ciitlahore.edu.pk [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Farooq, Ariba [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Shahzadi, Lubna; Khan, Abdul Samad [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Mahmood, Nasir [Department of Allied Health Sciences and Chemical Pathology, Department of Human Genetics and Molecular Biology, University of Health Sciences, Lahore (Pakistan); Rauf, Abdul [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Chaudhry, Aqif Anwar [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Rehman, Ihtesham ur [Interdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Department of Materials Science and Engineering, The Kroto Research Institute, The University of Sheffield, North Campus, Broad Lane, Sheffield S3 7HQ (United Kingdom)

    2016-07-01

    Periodontal disease is associated with the destruction of periodontal tissues, along with other disorders/problems including inflammation of tissues and severe pain. This paper reports the synthesis of meloxicam (MX) immobilized biodegradable chitosan (CS)/poly(vinyl alcohol) (PVA)/hydroxyapatite (HA) based electrospun (e-spun) fibers and films. Electrospinning was employed to produce drug loaded fibrous mats, whereas films were generated by solvent casting method. In-vitro drug release from materials containing varying concentrations of MX revealed that the scaffolds containing higher amount of drug showed comparatively faster release. During initial first few hours fast release was noted from membranes and films; however after around 5 h sustained release was achieved. The hydrogels showed good swelling property, which is highly desired for soft tissue engineered implants. To investigate the biocompatibility of our synthesized materials, VERO cells (epithelial cells) were selected and cell culture results showed that these all materials were non-cytotoxic and also these cells were very well proliferated on these synthesized scaffolds. These properties along with the anti-inflammatory potential of our fabricated materials suggest their effective utilization in periodontital treatments. - Highlights: • NSAIDs releasing scaffolds for periodontal regeneration applications • Meloxicam immobilized biodegradable nanocomposite electrospun membranes and films • Good swelling properties • Controlled drug release • VERO cells were very well proliferated and synthesized materials were found to be non-cytotoxic.

  11. Visual classification of braided and woven fiber bundles in X-ray computed tomography scanned carbon fiber reinforced polymer specimens

    Directory of Open Access Journals (Sweden)

    Johannes Weissenböck

    2016-11-01

    Full Text Available In recent years, advanced composite materials such as carbon fiber reinforced polymers (CFRP are used in many fields of application (e.g., automotive, aeronautic and leisure industry. These materials are characterized by their high stiffness and strength, while having low weight. Especially, woven carbon fiber reinforced materials have outstanding mechanical properties due to their fabric structure. To analyze and develop the fabrics, it is important to understand the course of the individual fiber bundles. Industrial 3D X-ray computed tomography (XCT as a nondestructive testing method allows resolving these individual fiber bundles. In this paper, we show our findings when applying the method of Bhattacharya et al. [6] for extracting fiber bundles on two new types of CFRP specimens. One specimen contains triaxial braided plies in an RTM6 resin and another specimen woven bi-diagonal layers. Furthermore, we show the required steps to separate the individual bundles and the calculation of the individual fiber bundles characteristics which are essential for the posterior visual analysis and exploration. We further demonstrate the classification of the individual fiber bundles within the fabrics to support the domain experts in perceiving the weaving structure of XCT scanned specimens.

  12. UV-Assisted 3D Printing of Glass and Carbon Fiber-Reinforced Dual-Cure Polymer Composites

    Directory of Open Access Journals (Sweden)

    Marta Invernizzi

    2016-07-01

    Full Text Available Glass (GFR and carbon fiber-reinforced (CFR dual-cure polymer composites fabricated by UV-assisted three-dimensional (UV-3D printing are presented. The resin material combines an acrylic-based photocurable resin with a low temperature (140 °C thermally-curable resin system based on bisphenol A diglycidyl ether as base component, an aliphatic anhydride (hexahydro-4-methylphthalic anhydride as hardener and (2,4,6,-tris(dimethylaminomethylphenol as catalyst. A thorough rheological characterization of these formulations allowed us to define their 3D printability window. UV-3D printed macrostructures were successfully demonstrated, giving a clear indication of their potential use in real-life structural applications. Differential scanning calorimetry and dynamic mechanical analysis highlighted the good thermal stability and mechanical properties of the printed parts. In addition, uniaxial tensile tests were used to assess the fiber reinforcing effect on the UV-3D printed objects. Finally, an initial study was conducted on the use of a sizing treatment on carbon fibers to improve the fiber/matrix interfacial adhesion, giving preliminary indications on the potential of this approach to improve the mechanical properties of the 3D printed CFR components.

  13. An experimental study of non-destructive testing on glass fibre reinforced polymer composites after high velocity impact event

    Science.gov (United States)

    Razali, N.; Sultan, M. T. H.; Cardona, F.

    2016-10-01

    A non-destructive testing method on Glass Fibre Reinforced Polymer (GFRP) after high velocity impact event using single stage gas gun (SSGG) is presented. Specimens of C- type and E-type fibreglass reinforcement, which were fabricated with 6mm, 8mm, 10mm and 12mm thicknesses and size 100 mm x 100 mm, were subjected to a high velocity impact with three types of bullets: conical, hemispherical and blunt at various gas gun pressure levels from 6 bar to 60 bar. Visual observation techniques using a lab microscope were used to determine the infringed damage by looking at the crack zone. Dye penetrants were used to inspect the area of damage, and to evaluate internal and external damages on the specimens after impact. The results from visual analysis of the impacted test laminates were discussed and presented. It was found that the impact damage started with induced delamination, fibre cracking and then failure, simultaneously with matrix cracking and breakage, and finally followed by the fibres pulled out. C-type experienced more damaged areas compared to E-type of GFRP.

  14. Rigid spine reinforced polymer microelectrode array probe and method of fabrication

    Science.gov (United States)

    Tabada, Phillipe; Pannu, Satinderpall S

    2014-05-27

    A rigid spine-reinforced microelectrode array probe and fabrication method. The probe includes a flexible elongated probe body with conductive lines enclosed within a polymeric material. The conductive lines connect microelectrodes found near an insertion end of the probe to respective leads at a connector end of the probe. The probe also includes a rigid spine, such as made from titanium, fixedly attached to the probe body to structurally reinforce the probe body and enable the typically flexible probe body to penetrate and be inserted into tissue, such as neural tissue. By attaching or otherwise fabricating the rigid spine to connect to only an insertion section of the probe body, an integrally connected cable section of the probe body may remain flexible.

  15. Statistical Analysis of the Progressive Failure Behavior for Fiber-Reinforced Polymer Composites under Tensile Loading

    Directory of Open Access Journals (Sweden)

    Fang Wang

    2014-01-01

    Full Text Available An analytical approach with the help of numerical simulations based on the equivalent constraint model (ECM was proposed to investigate the progressive failure behavior of symmetric fiber-reinforced composite laminates damaged by transverse ply cracking. A fracture criterion was developed to describe the initiation and propagation of the transverse ply cracking. This work was also concerned with a statistical distributions of the critical fracture toughness values with due consideration given to the scale size effect. The Monte Carlo simulation technique coupled with statistical analysis was applied to study the progressive cracking behaviors of composite structures, by considering the effects of lamina properties and lay-up configurations. The results deduced from the numerical procedure were in good agreement with the experimental results obtained for laminated composites formed by unidirectional fiber reinforced laminae with different orientations.

  16. Design and Development of Glass Fiber Reinforced Polymer Matrix Composites for Engineering Application

    OpenAIRE

    Vijayakumar, R.; , Dr.H.Maheshappa; Dr.Sarath Kumar Maharana; Dr.Yogananda

    2017-01-01

    An experimental investigation has been carried out to develop new PMC using commercially available Epoxy and Polyurethane resin systems. These resin systems would be reinforced with glass fibers, filler materials and aluminium foils. Laminates are prepared by using the hand lay-up techniques of eight layers and mechanical test such as tensile test and compression test have been conducted. This work has been carried out to identify the appropriate resin systems, filler materials and glass fibe...

  17. State-of-Practice on the Dynamic Response of Structures Strengthened with Fiber Reinforced Polymers (FRPs)

    Science.gov (United States)

    2015-07-01

    reinforced concrete beam using a nitrogen-gas, hydraulic loading ram. The tests were conducted at the U.S. Army Waterways Experiment Station, known today...specimens were subjected to cyclic lateral loads with load, horizontal drift, and strain at the splice bars and in the hoop direction of the FRP jacked ...a hydraulic actuator to simulate an earthquake load. The results of this study showed that all the retrofitted specimens had higher stiffnesses

  18. Carbon nanotube reinforced polymer composites–A state of the art

    Indian Academy of Sciences (India)

    Because of their high mechanical strength, carbon nanotubes (CNTs) are being considered as nanoscale fibres to enhance the performance of polymer composite materials. Novel CNT-based composites have been fabricated using different methods, expecting that the resulting composites would possess enhanced or ...

  19. Carbon nanotube reinforced polymer composites–A state of the art

    Indian Academy of Sciences (India)

    TECS

    Abstract. Because of their high mechanical strength, carbon nanotubes (CNTs) are being considered as nanoscale fibres to enhance the performance of polymer composite materials. Novel CNT-based composites have been fabricated using different methods, expecting that the resulting composites would possess ...

  20. Shrinkage Behaviour of Fibre Reinforced Concrete with Recycled Tyre Polymer Fibres

    Directory of Open Access Journals (Sweden)

    Marijana Serdar

    2015-01-01

    Full Text Available Different types of fibres are often used in concrete to prevent microcracking due to shrinkage, and polypropylene fibres are among the most often used ones. If not prevented, microcracks can lead to the development of larger cracks as drying shrinkage occurs, enabling penetration of aggressive substances from the environment and reducing durability of concrete structures. The hypothesis of the present research is that polypropylene fibres, used in concrete for controlling formation of microcracks due to shrinkage, can be replaced with recycled polymer fibres obtained from end-of-life tyres. To test the hypothesis, concrete mixtures containing polypropylene fibres and recycled tyre polymer fibres were prepared and tested. Experimental programme focused on autogenous, free, and restrained shrinkage. It was shown that PP fibres can be substituted with higher amount of recycled tyre polymer fibres obtaining concrete with similar shrinkage behaviour. The results indicate promising possibilities of using recycled tyre polymer fibres in concrete products. At the same time, such applications would contribute to solving the problem of waste tyre disposal.

  1. Optimisation of Fabric Reinforced Polymer Composites Using a Variant of Genetic Algorithm

    Science.gov (United States)

    Axinte, Andrei; Taranu, Nicolae; Bejan, Liliana; Hudisteanu, Iuliana

    2017-03-01

    Fabric reinforced polymeric composites are high performance materials with a rather complex fabric geometry. Therefore, modelling this type of material is a cumbersome task, especially when an efficient use is targeted. One of the most important issue of its design process is the optimisation of the individual laminae and of the laminated structure as a whole. In order to do that, a parametric model of the material has been defined, emphasising the many geometric variables needed to be correlated in the complex process of optimisation. The input parameters involved in this work, include: widths or heights of the tows and the laminate stacking sequence, which are discrete variables, while the gaps between adjacent tows and the height of the neat matrix are continuous variables. This work is one of the first attempts of using a Genetic Algorithm (GA) to optimise the geometrical parameters of satin reinforced multi-layer composites. Given the mixed type of the input parameters involved, an original software called SOMGA (Satin Optimisation with a Modified Genetic Algorithm) has been conceived and utilised in this work. The main goal is to find the best possible solution to the problem of designing a composite material which is able to withstand to a given set of external, in-plane, loads. The optimisation process has been performed using a fitness function which can analyse and compare mechanical behaviour of different fabric reinforced composites, the results being correlated with the ultimate strains, which demonstrate the efficiency of the composite structure.

  2. A Study of Bond of Structural Timber and Carbon Fiber Reinforced Polymer Plate

    Directory of Open Access Journals (Sweden)

    Yongtaeg LEE

    2015-11-01

    Full Text Available The increase of well-being culture of problem related to environmental depletion of resource is not the growing interest in timber the natural material of construction markets. Also, the perception for historic preservation has been increased in respond to heightened interest. However, it is fairly difficult for architectural properties to maintain their durability because it was made by timber construction. Preventing traditional structure from damage and structural performance reduction is paramount in maintenance problem. A number of studies of reinforced method have been conducted in order to solve such a problem. In this paper, external bonded reinforcement and near-surface mounted was used as a way to reinforce timber structure’s durability. Bond strength for specimens with different bond length was investigated. As a result showed, maximum bond strength in bond length 300 mm from all method, was found to be not increased of bond strength over the certain bond length.DOI: http://dx.doi.org/10.5755/j01.ms.21.4.9702

  3. Optimisation of Fabric Reinforced Polymer Composites Using a Variant of Genetic Algorithm

    Science.gov (United States)

    Axinte, Andrei; Taranu, Nicolae; Bejan, Liliana; Hudisteanu, Iuliana

    2017-12-01

    Fabric reinforced polymeric composites are high performance materials with a rather complex fabric geometry. Therefore, modelling this type of material is a cumbersome task, especially when an efficient use is targeted. One of the most important issue of its design process is the optimisation of the individual laminae and of the laminated structure as a whole. In order to do that, a parametric model of the material has been defined, emphasising the many geometric variables needed to be correlated in the complex process of optimisation. The input parameters involved in this work, include: widths or heights of the tows and the laminate stacking sequence, which are discrete variables, while the gaps between adjacent tows and the height of the neat matrix are continuous variables. This work is one of the first attempts of using a Genetic Algorithm ( GA) to optimise the geometrical parameters of satin reinforced multi-layer composites. Given the mixed type of the input parameters involved, an original software called SOMGA (Satin Optimisation with a Modified Genetic Algorithm) has been conceived and utilised in this work. The main goal is to find the best possible solution to the problem of designing a composite material which is able to withstand to a given set of external, in-plane, loads. The optimisation process has been performed using a fitness function which can analyse and compare mechanical behaviour of different fabric reinforced composites, the results being correlated with the ultimate strains, which demonstrate the efficiency of the composite structure.

  4. From dilute to entangled fiber suspensions involved in reinforced polymers and composites

    Science.gov (United States)

    Perez-Miguel, M.; Abisset-Chavanne, E.; Chinesta, F.; Keunings, R.

    2017-10-01

    In SMC processes, a charge of a composite material - which typically consists of a matrix reinforced with chopped glass fibres or carbon fibre bundles and fillers - is placed on the bottom half of a preheated mould. The upper half of the mould is then closed rapidly at a high speed, causing the charge to flow inside the cavity, the reinforcing fibres are carried by the resin and experience a change of configuration, which strongly influences the mechanical properties of the final part. Then, the process simulation must track the entire fluid flow history in order to be able to predict the final reinforcement structure, and predict the defects that compression moulding can generate. All along the process, the fiber concentration increases leading to a change in the flow regimes: (i) at very low concentrations, the fiber and the fluid are moving with the same velocity, (ii) when the concentration is extremely high, fibers cannot move anymore and the fluid flows throughout the quasi-rigid entangled fibers skeleton, (iii) in between these two cases, fibers move with a velocity lower than the one of the suspending fluid. The process simulations must then be able to take into account all these regimes and go from one to the other. Even if the two first regimes (dilute and highly concentrated) are well known and described using Jeffery's [4] and Darcy's equations, the transition between the two is still badly modeled. In this work a general model able to adapt continuously to all these scenarios is elaborated.

  5. Semiempirical Methodology for Estimating the Service Life of Concrete Deck Panels Strengthened with Fiber-Reinforced Polymer

    Directory of Open Access Journals (Sweden)

    Eon-Kyoung Kim

    2014-01-01

    Full Text Available Deterioration of concrete bridge decks affects their durability, safety, and function. It is therefore necessary to conduct structural rehabilitation of damaged concrete decks by strengthening them with fiber-reinforced polymer. Of the recent studies on the strengthened structures, most have focused on static behavior; only a few studies have investigated fatigue behavior. Accurate analysis of fatigue in concrete deck performance requires a more realistic simulated moving load. This study developed a theoretical live-load model to reflect the effect of moving vehicle loads, based on a statistical approach to the measurement of real traffic loads over various time periods in Korea. It assessed the fatigue life and strengthening effect of bridge decks strengthened with either carbon fiber sheets or grid carbon fiber polymer plastic using probabilistic and reliability analyses. It used extrapolations and simulations to derive maximum load effects for time periods ranging from 1 day to 75 years. Limited fatigue tests were conducted and probabilistic and reliability analyses were carried out on the strengthened concrete bridge deck specimens to predict the extended fatigue life. Analysis results indicated that strengthened concrete decks provide sufficient resistance against increasing truck loads during the service life of a bridge.

  6. Deformation behavior of carbon-fiber reinforced shape-memory-polymer composites used for deployable structures (Conference Presentation)

    Science.gov (United States)

    Lan, Xin; Liu, Liwu; Li, Fengfeng; Pan, Chengtong; Liu, Yanju; Leng, Jinsong

    2017-04-01

    Shape memory polymers (SMPs) are a new type of smart material, they perform large reversible deformation with a certain external stimulus (e.g., heat and electricity). The properties (e.g., stiffness, strength and other mechanically static or quasi-static load-bearing capacity) are primarily considered for conventional resin-based composite materials which are mainly used for structural materials. By contrast, the mechanical actuating performance with finite deformation is considered for the shape memory polymers and their composites which can be used for both structural materials and functional materials. For shape memory polymers and their composites, the performance of active deformation is expected to further promote the development in smart active deformation structures, such as deployable space structures and morphing wing aircraft. The shape memory polymer composites (SMPCs) are also one type of High Strain Composite (HSC). The space deployable structures based on carbon fiber reinforced shape memory polymer composites (SMPCs) show great prospects. Considering the problems that SMPCs are difficult to meet the practical applications in space deployable structures in the recent ten years, this paper aims to research the mechanics of deformation, actuation and failure of SMPCs. In the overall view of the shape memory polymer material's nonlinearity (nonlinearity and stress softening in the process of pre-deformation and recovery, relaxation in storage process, irreversible deformation), by the multiple verifications among theory, finite element and experiments, one obtains the deformation and actuation mechanism for the process of "pre-deformation, energy storage and actuation" and its non-fracture constraint domain. Then, the parameters of SMPCs will be optimized. Theoretical analysis is realized by the strain energy function, additionally considering the interaction strain energy between the fiber and the matrix. For the common resin-based or soft

  7. Degradation of Carbon Fiber Reinforced Polymer and Graphite by Laser Heating

    Science.gov (United States)

    2016-08-01

    divided into oxidative treatments (gas-phase, chemical, electrochemical, catalytic ) and non- oxidative treatments (carbon deposition, polymer grafting...planar and are more widely spaced, a form called turbostratic. These layers and the microdomains they form split , twist and fold among themselves to...transition temperature (approximately 120 °C). In the first degradation stage (250-300 °C), water is eliminated through a dehydration process, forming

  8. Wavelet Analysis of Acoustic Emissions during Tensile Test of Carbon Fibre Reinforced Polymer Composites

    Science.gov (United States)

    Świt, Grzegorz; Adamczak, Anna; Krampikowska, Aleksandra

    2017-10-01

    The increase of the interest in polymer composites in technology and in people’s everyday lives has been noticed in the recent years. Producing new materials with polymer matrix of particular properties that cannot be achieved by traditional construction materials contributed to high interest in fibre composite materials. However, a wider use of these materials is limited because of the lack of detailed knowledge about their properties and behaviour in various conditions of exposure under load. Mechanical degradation of polymer composites, which is caused by prolonged permanent loads, is connected with the changes of the material structure that are local or that include the whole volume of the element’s body. These changes are in the form of various types of discontinuity, including: deboning, matrix and fibers cracks and delamination. The article presents the example of the application of acoustic emission method based on the analysis of the waves through the use of wavelet analysis for the evaluation of the progress of the destructive processes and the level of the degradation of composite tapes that were subject to tensile testing.

  9. Design and Fabrication of Graphene Reinforced Polymer Conductive Patch-Based Inset Fed Microstrip Antenna

    Science.gov (United States)

    Deepak, A.; Kannan, P. Muthu; Shankar, P.

    This work explores the design and fabrication of graphene reinforced polyvinylidene fluoride (PVDF) patch-based microstrip antenna. Primarily, antenna was designed at 6GHz frequency and simulation results were obtained using Ansoft HFSS tool. Later fabrication of antenna was carried out with graphene-PVDF films as conducting patch deposited on bakelite substrate and copper as ground plane. Graphene-PVDF films were prepared using solvent casting process. The radiation efficiency of fabricated microstrip patch antenna was 48% entailing it to be adapted as a practically functional antenna. Both simulated and the practical results were compared and analyzed.

  10. Preparation of microstructured hydroxyapatite microspheres using ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Hydroxyapatite (HAP) microspheres with peculiar spheres-in-sphere morphology were prepared by using oil-in-water emulsions and solvent evaporation technique. Ethylene vinyl acetate co-polymer (EVA) was used as the binder material. Preparation of HAP/EVA microspheres was followed by the thermal de-.

  11. Reinforced poly(propylene oxide)- a very soft and extensible dielectric electroactive polymer

    DEFF Research Database (Denmark)

    Goswami, Kaustav; Galantini, F.; Mazurek, Piotr Stanislaw

    2013-01-01

    Poly(propylene oxide) (PPO), a novel soft elastomeric material, and its composites were investigated as a new dielectric electroactive polymer (EAP). The PPO networks were obtained from thiol-ene chemistry by photochemical crosslinking of ,!-diallyl PPO with a tetra-functional thiol. The elastomer...... of the otherwise mechanically weak pure PPO network. Dielectric spectroscopy revealed high relative dielectric permittivity of PPO at 103 Hz of 5.6. The relative permittivity was decreased slightly upon addition of fillers, but remained higher than the commonly used acrylic EAP material VHB4910...

  12. An integrated computational framework for simulating the failure response of carbon fiber reinforced polymer composites

    Science.gov (United States)

    Ahmadian, Hossein; Liang, Bowen; Soghrati, Soheil

    2017-12-01

    A new computational framework is introduced for the automated finite element (FE) modeling of fiber reinforced composites and simulating their micromechanical behavior. The proposed methodology relies on a new microstructure reconstruction algorithm that implements the centroidal Voronoi tessellation (CVT) to generate an initial uniform distribution of fibers with desired volume fraction and size distribution in a repeating unit cell of the composite. The genetic algorithm (GA) is then employed to optimize locations of fibers such that they replicate the target spatial arrangement. We also use a non-iterative mesh generation algorithm, named conforming to interface structured adaptive mesh refinement (CISAMR), to create FE models of the CFRPC. The CVT-GA-CISAMR framework is then employed to investigate the appropriate size of the composite's representative volume element. We also study the strength and failure mechanisms in the CFRPC subject to varying uniaxial and mixed-mode loadings.

  13. An integrated computational framework for simulating the failure response of carbon fiber reinforced polymer composites

    Science.gov (United States)

    Ahmadian, Hossein; Liang, Bowen; Soghrati, Soheil

    2017-08-01

    A new computational framework is introduced for the automated finite element (FE) modeling of fiber reinforced composites and simulating their micromechanical behavior. The proposed methodology relies on a new microstructure reconstruction algorithm that implements the centroidal Voronoi tessellation (CVT) to generate an initial uniform distribution of fibers with desired volume fraction and size distribution in a repeating unit cell of the composite. The genetic algorithm (GA) is then employed to optimize locations of fibers such that they replicate the target spatial arrangement. We also use a non-iterative mesh generation algorithm, named conforming to interface structured adaptive mesh refinement (CISAMR), to create FE models of the CFRPC. The CVT-GA-CISAMR framework is then employed to investigate the appropriate size of the composite's representative volume element. We also study the strength and failure mechanisms in the CFRPC subject to varying uniaxial and mixed-mode loadings.

  14. Damage Tolerance Enhancement of Carbon Fiber Reinforced Polymer Composites by Nanoreinforcement of Matrix

    Science.gov (United States)

    Fenner, Joel Stewart

    Nanocomposites are a relatively new class of materials which incorporate exotic, engineered nanoparticles to achieve superior material properties. Because of their extremely small size and well-ordered structure, many nanoparticles possess properties that exceed those offered by a wide range of other known materials, making them attractive candidates for novel materials engineering development. Their small size is also an impediment to their practical use, as they typically cannot be employed by themselves to realize those properties in large structures. Furthermore, nanoparticles typically possess strong self-affinity, rendering them difficult to disperse uniformly into a composite. However, contemporary research has shown that, if well-dispersed, nanoparticles have great capacity to improve the mechanical properties of composites, especially damage tolerance, in the form of fracture toughness, fatigue life, and impact damage mitigation. This research focuses on the development, manufacturing, and testing of hybrid micro/nanocomposites comprised of woven carbon fibers with a carbon nanotube reinforced epoxy matrix. Material processing consisted of dispersant-and-sonication based methods to disperse nanotubes into the matrix, and a vacuum-assisted wet lay-up process to prepare the hybrid composite laminates. Various damage tolerance properties of the hybrid composite were examined, including static strength, fracture toughness, fatigue life, fatigue crack growth rate, and impact damage behavior, and compared with similarly-processed reference material produced without nanoreinforcement. Significant improvements were obtained in interlaminar shear strength (15%), Mode-I fracture toughness (180%), shear fatigue life (order of magnitude), Mode-I fatigue crack growth rate (factor of 2), and effective impact damage toughness (40%). Observations by optical microscopy, scanning electron microscopy, and ultrasonic imaging showed significant differences in failure behavior

  15. In vitro bioactivity of polymer matrices reinforced with a bioactive glass phase

    Directory of Open Access Journals (Sweden)

    Oréfice Rodrigo L.

    2000-01-01

    Full Text Available Composites that can mimic the in vitro bioactive behavior of bioactive glasses were designed to fulfill two main features of bioactive glasses that are responsible for their high bond-to-bone rates: (1 capability of providing ions such as calcium and phosphate to the nearby environment and (2 ideal surface structure that allows fast heterogeneous precipitation of hydroxy-carbonate-apatite (HCA. The novel composites were prepared by incorporating bioactive glass particles into polymer matrices. The in vitro bioactivity test was performed by introducing samples into a buffered solution as well as into a simulated body fluid solution. FTIR was used to evaluate the kinetics of HCA (hydroxy-carbonate-apatite precipitation. The results showed that the obtained composites can supply ions, such as silicates and phosphates in rates and concentrations comparable or superior than bulk bioactive glasses. Moreover, the surface chemistry of the composites was altered to mimic the surface of bioactive glasses. It was demonstrated that the in vitro bioactivity of the composites was enhanced by chemically modifying polymer surfaces through the introduction of special alkoxysilane groups.

  16. On acoustic emission for damage detection and failure prediction in fiber reinforced polymer rods using pattern recognition analysis

    Science.gov (United States)

    Shateri, Mohammadhadi; Ghaib, Maha; Svecova, Dagmar; Thomson, Douglas

    2017-06-01

    Fiber reinforced polymer (FRP) rods are used for pre-stressing and reinforcing in civil engineering applications. Damage in FRP rods can lead to sudden brittle failure, therefore, a reliable method that provides indicators of damage progression and potential failure in FRP rods is highly desirable. Acoustic emission (AE) signal analysis has been used for damage detection and monitoring of FRP materials. In this study, a new AE event detection algorithm, utilizing the root mean square envelope of AE signal, is applied to AE data to isolate each AE event separately, even when AE events are nearly coincident. A fuzzy c-means (FCM) clustering algorithm is used to classify these isolated AE events into 3 clusters. Scanning electron microscopy images of FRP rod cross-sections also show 3 types of damage. The hypothesis in this study is that each cluster represents a damage mechanism. The number of events in each cluster is monitored versus the percent of the ultimate load. The ratio of the number of AE events in one of the FCM clusters to the number of AE events in another FCM cluster was useful for providing an indication of when the stress levels have reached the point where the loads may cause the FRP rod to fail. The results of applying this parameter to four FRP rods show a significant slope change (factor of 10) in this ratio at around 40% and 60% of the ultimate load for glass FRP rods and carbon FRP rods, respectively. This method may prove useful in damage progression and failure prediction of the FRP rods in prefabricated structures where pre-stressed FRP is used and in field monitoring of FRP materials.

  17. UTILIZATION OF MICRO SISAL FIBERS AS REINFORCEMENT AGENT AND POLYPROPYLENE OR POLYLACTIC ACID AS POLYMER MATRICES IN BIOCOMPOSITES MANUFACTURE

    Directory of Open Access Journals (Sweden)

    Subyakto Subyakto

    2013-06-01

    Full Text Available Sisal (Agave sisalana as a perennial tropical plant grows abundantly in Indonesia. Its fibers can be used as the reinforcement agent of biocomposite products. Utilization of sisal as natural fiber has some notable benefits compared to synthetic fibers, such as renewable, light in weight, and low in cost. Manufacture of biocomposite requires the use of matrix such as thermoplastic polymer, e.g. polypropylene (PP and polylactic acid (PLA to bond together with the reinforcement agent (e.g. sisal fibers. In relevant, experiment was conducted on biocomposites manufacture that comprised sisal fibers and PP as well as PLA. Sisal fibers were converted into pulp, then refined to micro-size fibrillated fibers such that their diameter reduced to about 10 μm, and dried in an oven. The dry microfibrillated sisal pulp fibers cellulose (MSFC were thoroughly mixed with either PP or PLA with varying ratios of MSFC/PP as well as MSFC/PLA, and then shaped into the mat (i.e. MSFC-PP and MSFC-PLA biocomposites. Two kinds of shaping was employed, i.e. hot-press molding and injection molding. In the hot-press molding, the ratio of  MSFC/PP as well as MSFC/PLA ranged about 30/70-50/50. Meanwhile in the injection (employed only on assembling the MSFC-PLA biocomposite, the ratio of MSFC/PLA varied about 10/90-30/70. The resulting shaped MSFC-PP and MSFC-PLA biocomposites were then tested of its physical and mechanical properties. With the hot-press molding device, the physical and mechanical (strength properties of MSFC-PLA biocomposite were higher than those of  MSFC-PP biocomposite. The optimum ratio of  MSFC/PP as well as MSFC/PLA reached concurrently at 40/60. The strengths of MSFC-PP as well as MSFC-PLA biocomposites were greater than those of individual polymer (PP and PLA. With the injection molding device, only the MSFC-PLA  biocomposite  was formed  and its strengths  reached  maximum  at 30/70  ratio.  The particular strengths (MOR and MOE of MSFC

  18. Understanding the Stress Relaxation Behavior of Polymers Reinforced with Short Elastic Fibers.

    Science.gov (United States)

    Obaid, Numaira; Kortschot, Mark T; Sain, Mohini

    2017-04-28

    Although it has been experimentally shown that the addition of short-fibers slows the stress relaxation process in composites, the underlying phenomenon is complex and not well understood. Previous studies have proposed that fibers slow the relaxation process by either hindering the movement of nearby polymeric chains or by creating additional covalent bonds at the fiber-matrix interface that must be broken before bulk relaxation can occur. In this study, we propose a simplified analytical model that explicitly accounts for the influence of polymer viscoelasticity on shear stress transfer to the fibers. This model adequately explains the effect of fiber addition on the relaxation behavior without the need to postulate structural changes at the fiber-matrix interface. The model predictions were compared to those from Monte Carlo finite-element simulations, and good agreement between the two was observed.

  19. Surface characterization of alumina reinforced with niobium carbide obtained by polymer precursor

    Directory of Open Access Journals (Sweden)

    Wilson Acchar

    2006-09-01

    Full Text Available Active filler controlled pyrolysis of polymers (AFCOP is a recent method for obtaining near-net shaped ceramic bodies. Alumina based composites have been developed for use as cutting tools, so knowledge of the surface composition is extremely important because it is directly related to the hardness and wear resistance Samples containing a fixed concentration of 60 wt. (% of polysiloxane and a mixture of metallic niobium and alumina powder were homogenized, uniaxially warm pressed at 80 °C and subsequently pyrolyzed in flowing argon at 1200, 1400 and 1500 °C. Analysis of the surface composition was carried out by X ray photoelectron spectroscopy, infrared spectroscopy, X ray diffraction and scanning electron microscopy. The results have indicated that the formation of the phases on the surface depends strongly on the niobium/carbon ratio in the raw materials.

  20. Mechanical and durability characteristics of externally GFRP reinforced unsaturated polyester polymer concrete

    Science.gov (United States)

    Bouguessir, H.; Harkati, E.; Rokbi, M.; Priniotakis, G.; Vassiliadis, S.

    2017-10-01

    The last decades of the XXe century cognized a huge extent of composite materials uses to almost all everyday life’s applications, replacing the conventional materials, due to their outstanding properties especially highest strength-to-weight ratio and the ability to be designed to satisfy specific performance requirements. To get the most out of these wonder materials, a new concept, combining polymer concrete and composite laminates, is currently used in Algeria. This research work has the aim to investigate applicability of this concept in civil engineering through tensile and bending tests. On the other hand, the influence of various chemicals (Sodium hydroxide, Potassium Hydroxide and Calcium Carbonates) on our material and its tensile properties retention over long-time exposure was examined. The mechanical properties obtained indicate the convenience of this material for use in civil engineering thanks to its very good tensile and flexural performances in addition to its sufficient residual strength after theoretically 56 years.

  1. Effect of oil palm empty fruit bunches fibers reinforced polymer recycled

    Science.gov (United States)

    Hermawan, B.; Nikmatin, S.; Sudaryanto; Alatas, H.; Sukaryo, S. G.

    2017-07-01

    The aim of this research is to process the OPEFB to become fiber with various sizes which will be used as a filler of polymer matrix recycled acrylonitrile butadiene styrene (ABS). Molecular analysis and mechanical test have been done to understand the influence of fiber size toward material capability to receive outer deformation. Single screw extruder formed a biocomposites granular continued with injection moulding to shaped test pieces. Maleic anhydride was added as coupling agent between filler and matrix. Filler concentration were 10 and 20% in fiber size respectively with constant additif. Two kind of fiber glass (10%) were used as comparator. In order to analyze the results of the mechanical test Fisher least significant difference (LSD) in ANOVA method was performed (-with α=0,05-).

  2. Investigation on Mechanical Properties of Coir Fiber Reinforced Polymer Resin Composites Saturated with Different Filling Agents

    Science.gov (United States)

    Nallusamy, S.; Suganthini Rekha, R.; Karthikeyan, A.

    2017-08-01

    The main objective of this research article is to assess the mechanical properties and fracture analysis of bone and sea shell powders independently integrated with coir fiber polymer composites. The specimen was fabricated with coir fiber at various dimensions of coir fiber like diameter, length, content and mesh size of the powder. Tensile, compressive, flexural and impact tests were conducted in the prepared composite materials as per the techniques of ASTM standard. The fracture faces were explored with the help of SEM images. From the final results it was concluded that the sea shell powder composite provides good tensile and flexural strength than bone powder composite, while bone powder composite material gives good compressive and impact strength than sea shell powder composite material.

  3. Mechanical and thermal properties of Posidonia oceanica cellulose nanocrystal reinforced polymer.

    Science.gov (United States)

    Bettaieb, Fedia; Khiari, Ramzi; Dufresne, Alain; Mhenni, Mohamed Farouk; Belgacem, Mohamed Naceur

    2015-06-05

    In the present study, cellulose nanocrystals (CNC) were isolated from Posidonia oceanica balls and leaves. CNC was prepared from this marine biomass by sulfuric acid hydrolysis (H2SO4) treatment. The raw fibers were firstly isolated by a delignification-bleaching process then the acid hydrolysis treatment was performed at 55°C during 40min under mechanical stirring. The ensuing CNCs were characterized by their morphological and thermal properties using transmission electron microscopy (TEM) and thermal gravimetric analysis (TGA), respectively. Nanocomposite materials using the CNC extracted from marine biomass were obtained by casting and evaporating a mixture of this suspension with poly(styrene-co-butyl acrylate). The effect of CNC loading on mechanical and thermal properties was studied. Dynamic mechanical analysis (DMA) results showed a strong reinforcing effect of CNC that depends on their origin (balls or leaves). The difference was attributed not only to differences in the aspect ratio of CNC but also to the stiffness of the percolating network of nanoparticles. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Preparation and characterization of ramie-glass fiber reinforced polymer matrix hybrid composites

    Directory of Open Access Journals (Sweden)

    Daiane Romanzini

    2012-06-01

    Full Text Available The use of ramie fibers as reinforcement in hybrid composites is justified considering their satisfactory mechanical properties if compared with other natural fibers. This study aims to verify changes in chemical composition and thermal stability of the ramie fibers after washing with distilled water. One additional goal is to study glass fiber and washed ramie fiber composites focusing on the effect of varying both the fiber length (25, 35, 45 and 55 mm and the fiber composition. The overall fiber loading was maintained constant (21 vol.%. Based on the results obtained, the washed ramie fiber may be considered as an alternative for the production of these composites. The higher flexural strength presented being observed for 45 mm fiber length composite, although this difference is not significant for lower glass fiber volume fractions: (0:100 and (25:75. Also, by increasing the relative volume fraction of glass fiber until an upper limit of 75%, higher flexural and impact properties were obtained.

  5. Mechanical properties of neat polymer matrix materials and their unidirectional carbon fiber-reinforced composites

    Science.gov (United States)

    Zimmerman, Richard S.; Adams, Donald F.

    1988-01-01

    The mechanical properties of two neat resin systems for use in carbon fiber epoxy composites were characterized. This included tensile and shear stiffness and strengths, coefficients of thermal and moisture expansion, and fracture toughness. Tests were conducted on specimens in the dry and moisture-saturated states, at temperatures of 23, 82 and 121 C. The neat resins tested were American Cyanamid 1806 and Union Carbide ERX-4901B(MPDA). Results were compared to previously tested neat resins. Four unidirectional carbon fiber reinforced composites were mechanically characterized. Axial and transverse tension and in-plane shear strengths and stiffness were measured, as well as transverse coefficients of thermal and moisture expansion. Tests were conducted on dry specimens only at 23 and 100 C. The materials tested were AS4/3502, AS6/5245-C, T300/BP907, and C6000/1806 unidirectional composites. Scanning electron microscopic examination of fracture surfaces was performed to permit the correlation of observed failure modes with the environmental test conditions.

  6. Flexure Behavior of Hybrid Continuous Deep Beam Strengthened by Carbon Fiber Reinforced Polymer

    Directory of Open Access Journals (Sweden)

    Hayder M.K.Al-Mutairee

    2017-08-01

    Full Text Available This study present an experimental investigation for overall flexure behavior of reinforced concrete continuous deep beams (RCCDB made of hybrid concrete, normal strength concrete (NSC and high strength concrete (HSC at different location and percentage. The experimental work includes testing of sixteen specimens of RCCDB under two points loads. The effects of HSC layer thickness and CFRP on strength of RCCDB had been studied. The experimental results showed that the strengthening of RCCDB by HSC layer from top is better than from bottom, where the increment in the ultimate flexural strength increased by (14,21,27% for top strengthening and (12,15,13% for bottom strengthening for (25,50,75% thickness of total depth of beam respectively. The optimal strengthening of RCCDB by HSC layer at top was of 25%. The results also proved that the strengthening of hybrid RCCDB by (10,15cm CFRP strip at the bottom for flexure gave increment in the ultimate strength by (32, 29% respectively, and the strengthening by CFRP strip for flexure at the bottom is better than at top for hybrid RCCDB. The shear strengthening of hybrid RCCDB increases the ultimate strength by 23.4% and 13.8% if the strengthening has O and U shape respectively

  7. An investigation into minimising total energy consumption and total completion time in a flexible job shop for recycling carbon fiber reinforced polymer

    OpenAIRE

    Liu, Ying; Tiwari, Ashutosh

    2015-01-01

    The increased use of carbon fiber reinforced polymer (CFRP) in industry coupled with European Union restrictions on landfill disposal has resulted in a need to develop relevant recycling technologies. Several methods, such as mechanical grinding, thermolysis and solvolysis, have been tried to recover the carbon fibers. Optimisation techniques for reducing energy consumed by above processes have also been developed. However, the energy efficiency of recycling CFRP at the workshop leve...

  8. Glass fiber-reinforced polymer packaged fiber Bragg grating sensors for low-speed weigh-in-motion measurements

    Science.gov (United States)

    Al-Tarawneh, Mu'ath; Huang, Ying

    2016-08-01

    The weight of rolling trucks on roads is one of the critical factors for the management of road networks due to the continuous increase in truck weight. Weigh-in-motion (WIM) sensors have been widely used for weight enforcement. A three-dimensional glass fiber-reinforced polymer packaged fiber Bragg grating sensor (3-D GFRP-FBG) is introduced for in-pavement WIM measurement at low vehicle passing speed. A sensitivity study shows that the developed sensor is very sensitive to the sensor installation depth and the longitudinal and transverse locations of the wheel loading position. The developed 3-D GFRP-FBG sensor is applicable for most practical pavements with a panel length larger than 6 ft, and it also shows a very good long-term durability. For the three components in 3-D of the developed sensor, the longitudinal component has the highest sensitivity for WIM measurements, followed by the transverse and vertical components. Field testing validated the sensitivity and repeatability of the developed 3-D GFRP-FBG sensor. The developed sensor provides the transportation agency one alternative solution for WIM measurement, which could significantly improve the measurement efficiency and long-term durability.

  9. Computational modeling of the electromagnetic characteristics of carbon fiber-reinforced polymer composites with different weave structures

    Science.gov (United States)

    Hassan, A. M.; Douglas, J. F.; Garboczi, E. J.

    2014-02-01

    Carbon fiber reinforced polymer composites (CFRPC) are of great interest in the aerospace and automotive industries due to their exceptional mechanical properties. Carbon fibers are typically woven and inter-laced perpendicularly in warps and wefts to form a carbon fabric that can be embedded in a binding matrix. The warps and wefts can be interlaced in different patterns called weaving structures. The primary weaving structures are the plain, twill, and satin weaves, which give different mechanical composite properties. The goal of this work is to computationally investigate the dependence of CFRPC microwave and terahertz electromagnetic characteristics on weave structure. These bands are good candidates for the Nondestructive Evaluation (NDE) of CFRPC since their wavelengths are comparable to the main weave features. 3D full wave electromagnetic simulations of several different weave models have been performed using a finite element (FEM) simulator, which is able to accurately model the complex weave structure. The computational experiments demonstrate that the reflection of electromagnetic waves from CFRPC depend sensitively on weave structure. The reflection spectra calculated in this work can be used to identify the optimal frequencies for the NDE of each weave structure.

  10. Coupling of a structural analysis and flow simulation for short-fiber-reinforced polymers: property prediction and transfer of results

    Science.gov (United States)

    Kröner, C.; Altenbach, H.; Naumenko, K.

    2009-05-01

    The aim of this paper is to discuss the basic theories of interfaces able to transfer the results of an injection molding analyis of fiber-reinforced polymers, performed by using the commercial computer code Moldflow, to the structural analysis program ABAQUS. The elastic constants of the materials, such as Young's modulus, shear modulus, and Poisson's ratio, which depend on both the fiber content and the degree of fiber orientation, were calculated not by the usual method of "orientation averaging," but with the help of linear functions fitted to experimental data. The calculation and transfer of all needed data, such as material properties, geometry, directions of anisotropy, and so on, is performed by an interface developed. The interface is suit able for midplane elements in Moldflow. It calculates and transfers to ABAQUS all data necessary for the use of shell elements. In addition, a method is described how a nonlinear orthotropic behavior can be modeled starting from the generalized Hooke's law. It is also shown how such a model can be implemented in ABAQUS by means of a material subroutine. The results obtained according to this subroutine are compared with those based on an orthotropic, linear, elastic simulation.

  11. Effect of fabrication processes on mechanical properties of glass fiber reinforced polymer composites for 49 meter (160 foot recreational yachts

    Directory of Open Access Journals (Sweden)

    Dave (Dae-Wook Kim

    2010-03-01

    Full Text Available Polymer composite materials offer high strength and stiffness to weight ratio, corrosion resistance, and total life cost reductions that appeal to the marine industry. The advantages of composite construction have led to their incorporation in U.S. yacht hull structures over 46 meters (150 feet in length. In order to construct even larger hull structures, higher quality composites with lower cost production techniques need to be developed. In this study, the effect of composite hull fabrication processes on mechanical properties of glass fiber reinforced plastic (GFRP composites is presented. Fabrication techniques investigated during this study are hand lay-up (HL, vacuum infusion (VI, and hybrid (HL + VI processes. Mechanical property testing includes: tensile, compressive, and ignition loss sample analysis. Results demonstrate that the vacuum pressure implemented during composite fabrication has an effect on mechanical properties. The VI processed GFRP yields improved mechanical properties in tension/compression strengths and tensile modulus. The hybrid GFRP composites, however, failed in a sequential manor, due to dissimilar failure modes in the HL and VI processed sides. Fractography analysis was conducted to validate the mechanical property testing results.

  12. Combined Effects of Sustained Loads and Wet-Dry Cycles on Durability of Glass Fiber Reinforced Polymer Composites

    Directory of Open Access Journals (Sweden)

    Mengting Li

    2017-01-01

    Full Text Available This paper deals with durability of glass fiber reinforced polymer (GFRP composites under the combined effects of sustained tensile loads and wet-dry (WD cycles. Two different solutions (distilled water and saltwater were used to imitate the freshwater and marine environments, respectively. Tensile properties of the unconditioned and conditioned specimens were measured to study the durability of GFRP composites under these 2 effects. The response indicated that both tensile strength and elastic modulus increased initially upon WD cycles, which was attributed to both the postcuring of resin and the sustained tensile stress allowing for fastec cure. Further exposure to WD cycles in distilled water or saltwater led to a steady decrease in tensile strength and modulus. WD cycles of saltwater and distilled water have similar effects on the degradation of the tensile properties for unstressed specimens. However, the elastic modulus and elongation at rupture of stressed specimens under WD cycles of saltwater decreased more than those specimens under WD cycles of distilled water. Moreover, increase of sustained loads led to a decrease in tensile strength. Based on Arrhenius method, a prediction model which accounted for the effects of postcure processes was developed. The predicted results of tensile strength and elastic modulus agree well with those obtained from the experiments.

  13. Carbon fiber reinforced polymer dimensional stability investigations for use on the laser interferometer space antenna mission telescope.

    Science.gov (United States)

    Sanjuán, J; Preston, A; Korytov, D; Spector, A; Freise, A; Dixon, G; Livas, J; Mueller, G

    2011-12-01

    The laser interferometer space antenna (LISA) is a mission designed to detect low frequency gravitational waves. In order for LISA to succeed in its goal of direct measurement of gravitational waves, many subsystems must work together to measure the distance between proof masses on adjacent spacecraft. One such subsystem, the telescope, plays a critical role as it is the laser transmission and reception link between spacecraft. Not only must the material that makes up the telescope support structure be strong, stiff, and light, but it must have a dimensional stability of better than 1 pm Hz(-1/2) at 3 mHz and the distance between the primary and the secondary mirrors must change by less than 2.5 μm over the mission lifetime. Carbon fiber reinforced polymer is the current baseline material; however, it has not been tested to the pico meter level as required by the LISA mission. In this paper, we present dimensional stability results, outgassing effects occurring in the cavity and discuss its feasibility for use as the telescope spacer for the LISA spacecraft.

  14. An overview of the Oil Palm Empty Fruit Bunch (OPEFB potential as reinforcing fibre in polymer composite for energy absorption applications

    Directory of Open Access Journals (Sweden)

    Faizi M.K.

    2017-01-01

    Full Text Available The oil palm empty fruit bunch (OPEFB natural fibres were comprehensively reviewed to assess their potential as reinforcing materials in polymer composites for energy absorption during low-velocity impact. The typical oil palm wastes include trunks, fronds, kernel shells, and empty fruit bunches. This has a tendency to burden the industry players with disposal difficulties and escalates the operating cost. Thus, there are several initiatives have been employed to convert these wastes into value added products. The objective of this study is to review the potential of oil palm empty fruit bunch (OPEFB as natural fibre polymer composite reinforcement to absorb the energy during low-velocity impact as another option for value added products. Initially, this paper reviewed the local oil palm waste issues. Previous research works on OPEFB polymer composite, and their mechanical characterization is appraised. Their potential for energy absorption in low-velocity impact application was also elaborated. The review suggests high potential applications of OPEFB as reinforcing materials in composite structures. Furthermore, it is wisely to utilize the oil palm biomass waste into a beneficial composite, hence, promotes the green environment.

  15. Biodegradable polymer films from seaweed polysaccharides: A review on cellulose as a reinforcement material

    Directory of Open Access Journals (Sweden)

    H. P. S. Abdul Khalil

    2017-04-01

    Full Text Available Seaweed and cellulose are promising natural polymers. This article reviews the basic information and recent developments of both seaweed and cellulose biopolymer materials as well as analyses the feasible formation of seaweed/cellulose composite films. Seaweed and cellulose both exhibit interesting film-forming properties. Nevertheless, seaweed has poor water vapour barrier and mechanical properties, whereas cellulose is neither meltable nor soluble in water or common organic solvents due to its highly crystalline structure. Therefore, modification of these hydrocolloids has been done to exploit their useful properties. Blending of biopolymers is a must recommended approach to improve the desired characteristics. From the review, seaweed is well compatible with cellulose, which possesses excellent mechanical strength and water resistance properties. Moreover, seaweed/cellulose composite films can prolong a product’s shelf life while maintaining its biodegradability. Additionally, the films show potential in contributing to the bioeconomy. In order to widen seaweed and cellulose in biocomposite application across various industries, some of the viewpoints are highlighted to be focused for future developments and applications.

  16. Reinforcing Germanium Electrode with Polymer Matrix Decoration for Long Cycle Life Rechargeable Lithium Ion Batteries.

    Science.gov (United States)

    Sun, Xiaolei; Lu, Xueyi; Huang, Shaozhuan; Xi, Lixia; Liu, Lixiang; Liu, Bo; Weng, Qunhong; Zhang, Lin; Schmidt, Oliver G

    2017-11-08

    Germanium is a promising anode material for lithium ion batteries because of its high theoretical specific capacity and low operation voltage. However, a significant challenge in using Ge-based anodes is the large volume variation during cycling that causes pulverization and capacity fade. Despite intense studies in the past decade, unsatisfactory cycling stability of the Ge-based electrodes still impedes their widespread applications. In this study, we demonstrate a high-performance electrode through the synergistic combination of a high-capacity Ge film grown on a three-dimensional current collector and an in situ formed poly(vinylidene fluoride)-hexafluoropropene/SiO2 protective layer. Specifically, the polymer matrix is in continuous contact with the surface of the Ge shell, which provides improved mechanical and ionic transport properties. As a highlight, we present impressive cycling stability over 3000 cycles at 1 C rate with a capacity retention as high as 95.7%. Furthermore, the LiCoO2-Ge full battery operates at an average voltage of 3.3 V at 0.5 C and maintains good electrochemical performance, suggesting great potential for applications in energy storage and conversion devices.

  17. Influence of Cutting Temperature on the Tensile Strength of a Carbon Fiber-Reinforced Polymer

    Directory of Open Access Journals (Sweden)

    Jérémy Delahaigue

    2017-12-01

    Full Text Available Carbon fiber-reinforced plastics (CFRP have seen a significant increase in use over the years thanks to their specific properties. Despite continuous improvements in the production methods of laminated parts, a trimming operation is still necessary to achieve the functional dimensions required by engineering specifications. Laminates made of carbon fibers are very abrasive and cause rapid tool wear, and require high cutting temperatures. This creates damage to the epoxy matrix, whose glass-transition temperature is often recognized to be about 180 °C. This study aims to highlight the influence of the cutting temperature generated by tool wear on the surface finish and mechanical properties obtained from tensile tests. Trimming operations were performed on a quasi-isotropic 24-ply carbon/epoxy laminate, of 3.6 mm thickness, with a 6 flutes diamond-coated (CVD cutter. The test specimens of 6 mm and 12 mm wide were obtained by trimming. The reduced width of the coupons allowed amplification of the effect of defects on the measured properties by increasing the proportion of coupon cross-section occupied by the defects. A new tool and a tool in an advanced state of wear were used to generate different cutting temperatures. Results showed a cutting temperature of 300 °C for the new tool and 475 °C for the worn tool. The analysis revealed that the specimens machined with the new tool have no thermal damage and the cut is clean. The plies oriented at −45° presented the worst surface finish according to the failure mode of the fiber. For the worn tool, the surface was degraded and the matrix was carbonized. After cutting, observations showed a degraded resin spread on the machined surface, which reduced the surface roughness and hid the cutting defects. In support of these observations, the tensile tests showed no variation of the mechanical properties for the 12 mm-wide specimens, but did show a 10% loss in mechanical properties for the 6 mm

  18. Effect of high energy electron beam (10MeV) on specific heat capacity of low-density polyethylene/hydroxyapatite nano-composite.

    Science.gov (United States)

    Soltani, Z; Ziaie, F; Ghaffari, M; Beigzadeh, A M

    2017-02-01

    In the present work, thermal properties of low density polyethylene (LDPE) and its nano composites are investigated. For this purpose LDPE reinforced with different weight percents of hydroxyapatite (HAP) powder which was synthesized via hydrolysis method are produced. The samples were irradiated with 10MeV electron beam at doses of 75 to 250kGy. Specific heat capacity measurement have been carried out at different temperatures, i.e. 25, 50, 75 and 100°C using modulated temperature differential scanning calorimetry (MTDSC) apparatus and the effect of three parameters include of temperature, irradiation dose and the amount of HAP nano particles as additives on the specific heat capacity of PE/HAP have been investigated precisely. The MTDSC results indicate that the specific heat capacity have decreased by addition of nano sized HAP as reinforcement for LDPE. On the other hand, the effect of radiation dose is reduction in the specific heat capacity in all materials including LDPE and its nano composites. The HAP nano particles along with cross-link junctions due to radiation restrain the movement of the polymer chains in the vicinity of each particle and improve the immobility of polymer chains and consequently lead to reduction in specific heat capacity. Also, the obtained results confirm that the radiation effect on the specific heat capacity is more efficient than the reinforcing effect of nano-sized hydroxyapatite. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Experimental Study of the Flexural and Compression Performance of an Innovative Pultruded Glass-Fiber-Reinforced Polymer-Wood Composite Profile

    Science.gov (United States)

    Qi, Yujun; Xiong, Wei; Liu, Weiqing; Fang, Hai; Lu, Weidong

    2015-01-01

    The plate of a pultruded fiber-reinforced polymer or fiber-reinforced plastic (FRP) profile produced via a pultrusion process is likely to undergo local buckling and cracking along the fiber direction under an external load. In this study, we constructed a pultruded glass-fiber-reinforced polymer-light wood composite (PGWC) profile to explore its mechanical performance. A rectangular cross-sectional PGWC profile was fabricated with a paulownia wood core, alkali-free glass fiber filaments, and unsaturated phthalate resin. Three-point bending and short column axial compression tests were conducted. Then, the stress calculation for the PGWC profile in the bending and axial compression tests was performed using the Timoshenko beam theory and the composite component analysis method to derive the flexural and axial compression rigidity of the profile during the elastic stress stage. The flexural capacity for this type of PGWC profile is 3.3-fold the sum of the flexural capacities of the wood core and the glass-fiber-reinforced polymer (GFRP) shell. The equivalent flexural rigidity is 1.5-fold the summed flexural rigidity of the wood core and GFRP shell. The maximum axial compressive bearing capacity for this type of PGWC profile can reach 1.79-fold the sum of those of the wood core and GFRP shell, and its elastic flexural rigidity is 1.2-fold the sum of their rigidities. These results indicate that in PGWC profiles, GFRP and wood materials have a positive combined effect. This study produced a pultruded composite material product with excellent mechanical performance for application in structures that require a large bearing capacity. PMID:26485431

  20. A Retrofit Theory to Prevent Fatigue Crack Initiation in Aging Riveted Bridges Using Carbon Fiber-Reinforced Polymer Materials

    Directory of Open Access Journals (Sweden)

    Elyas Ghafoori

    2016-08-01

    Full Text Available Most research on fatigue strengthening of steel has focused on carbon fiber-reinforced polymer (CFRP strengthening of steel members with existing cracks. However, in many practical cases, aging steel members do not yet have existing cracks but rather are nearing the end of their designed fatigue life. Therefore, there is a need to develop a “proactive” retrofit solution that can prevent fatigue crack initiation in aging bridge members. Such a proactive retrofit approach can be applied to bridge members that have been identified to be deficient, based on structural standards, to enhance their safety margins by extending the design service life. This paper explains a proactive retrofit design approach based on constant life diagram (CLD methodology. The CLD approach is a method that can take into account the combined effect of alternating and mean stress magnitudes to predict the high-cycle fatigue life of a material. To validate the retrofit model, a series of new fatigue tests on steel I-beams retrofitted by the non-prestressed un-bonded CFRP plates have been conducted. Furthermore, this paper attempts to provide a better understanding of the behavior of un-bonded retrofit (UR and bonded retrofit (BR systems. Retrofitting the steel beams using the UR system took less than half of the time that was needed for strengthening with the BR system. The results show that the non-prestressed un-bonded ultra-high modulus (UHM CFRP plates can be effective in preventing fatigue crack initiation in steel members.

  1. Multi-scale bending, buckling and vibration analyses of carbon fiber/carbon nanotube-reinforced polymer nanocomposite plates with various shapes

    Science.gov (United States)

    Ahmadi, M.; Ansari, R.; Rouhi, H.

    2017-09-01

    Using a finite element-based multi-scale modeling approach, the bending, buckling and free vibration of hybrid polymer matrix composites reinforced by carbon fibers and carbon nanotubes (CF/CNT-RP) are analyzed herein. Thick composite plates with rectangular, circular, annular and elliptical shapes are considered. First, the equivalent material properties of CF/CNT-RP are calculated for different volume fractions of CF and CNT. To accomplish this aim, a two-step procedure is presented through which the coupled effects of nano- and micro-scale are taken into account. In the first step, modeling of dispersion of CNTs into the polymer matrix is done with considering interphase formed by their chemical interaction with the matrix, and the equivalent properties of resulting composite material are determined accordingly. CFs are then dispersed into CNT-RP which is considered a homogenous material in this step. Both distributions of CNTs and CFs are assumed to be random. After computing the equivalent properties of CF/CNT-RP for different volume fractions of its constituents, the bending, buckling and free vibration analyses of plates with different shapes are performed. It is shown that the reinforcement of the polymer matrix with both CF and CNT significantly affects the bending, buckling and free vibration characteristics of plates.

  2. Effect of finish line variants on marginal accuracy and fracture strength of ceramic optimized polymer/fiber-reinforced composite crowns.

    Science.gov (United States)

    Cho, LeeRa; Choi, JongMi; Yi, Yang Jin; Park, Chan Jin

    2004-06-01

    Ceramic optimized polymer (Ceromer)/fiber-reinforced composite (FRC) crowns have been promoted as alternatives to conventional crowns. However, little is known regarding the ideal tooth preparation for this type of crown. This in vitro study evaluated the marginal adaptation and fracture strength of ceromer/FRC crowns with respect to the various types of finish lines. Four metal dies with different finish lines (0.9-mm chamfer, 1.2-mm chamfer, 1.2-mm rounded shoulder, and 1.2-mm shoulder) were prepared. Forty (10 for each finish line) Targis/Vectris crowns were fabricated on duplicated base metal alloy dies. The restorations were stereoscopically evaluated at 56 points along the entire circumferential margin for measuring the margin adaptation before and after cementation with a resin luting agent. The specimens were then compressively loaded to failure using a universal testing machine. The marginal adaptation (microm) was analyzed with the Kruskal-Wallis test and post-hoc Dunnett test (alpha=.05). The fracture load (N) was analyzed with a 1-way analysis of the variance and the Scheffe adjustment (alpha=.05). The fractured surfaces of the crowns were examined with a scanning electron microscope to determine the mode of fracture. The marginal adaptation of crowns with a shoulder finish line was significantly better than crowns with a chamfer finish line before and after cementation (P<.001). The increased marginal gap after cementation was the lowest in the 1.2-mm rounded shoulder group. The fracture strength of the crowns with the 0.9-mm chamfer and crowns with 1.2-mm chamfer was significantly greater than those of the crowns with the 1.2-mm shoulder or rounded shoulder (P=.011, P=.049, respectively). The mean fracture load of all crowns, regardless of the finish line design, was 1646 N. The fractured surface of the crown revealed adhesive failure and 3 types of cohesive failure (fracture of the Targis and Vectris, Targis fracture with a crack in the Vectris layer

  3. Acoustic emission and acousto-ultrasonic signature analysis of failure mechanisms in carbon fiber reinforced polymer materials

    Science.gov (United States)

    Carey, Shawn Allen

    Fiber reinforced polymer composite materials, particularly carbon (CFRPs), are being used for primary structural applications, particularly in the aerospace and naval industries. Advantages of CFRP materials, compared to traditional materials such as steel and aluminum, include: light weight, high strength to weight ratio, corrosion resistance, and long life expectancy. A concern with CFRPs is that despite quality control during fabrication, the material can contain many hidden internal flaws. These flaws in combination with unseen damage due to fatigue and low velocity impact have led to catastrophic failure of structures and components. Therefore a large amount of research has been conducted regarding nondestructive testing (NDT) and structural health monitoring (SHM) of CFRP materials. The principal objective of this research program was to develop methods to characterize failure mechanisms in CFRP materials used by the U.S. Army using acoustic emission (AE) and/or acousto-ultrasonic (AU) data. Failure mechanisms addressed include fiber breakage, matrix cracking, and delamination due to shear between layers. CFRP specimens were fabricated and tested in uniaxial tension to obtain AE and AU data. The specimens were designed with carbon fibers in different orientations to produce the different failure mechanisms. Some specimens were impacted with a blunt indenter prior to testing to simulate low-velocity impact. A signature analysis program was developed to characterize the AE data based on data examination using visual pattern recognition techniques. It was determined that it was important to characterize the AE event , using the location of the event as a parameter, rather than just the AE hit (signal recorded by an AE sensor). A back propagation neural network was also trained based on the results of the signature analysis program. Damage observed on the specimens visually with the aid of a scanning electron microscope agreed with the damage type assigned by the

  4. Whiskers and fibers of hydroxyapatite; Whiskers e fibras de hidroxiapatita

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, G.B.C.; Motisuke, M.; Zavaglia, C.A.C., E-mail: guicardoso@fem.unicamp.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Engenharia de Materiais; Arruda, A.C.F. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Engenharia de Petroleo

    2009-07-01

    Hydroxyapatite is a bioactive ceramic, which acts in tissue engineering by attracting bone cells. Occasionally it can be used as a biocompatible reinforcement. The mechanical role of this biomaterial can be defined depending of some characteristics analyzed by scanning electron microscope and X ray power diffraction. It can be classified in whiskers and fibers; each one has their own properties, which were discussed in this work. For its use as reinforcement it is necessary matrix with specific characteristics. (author)

  5. Hydroxyapatite scaffolds infiltrated with thermally crosslinked polycaprolactone fumarate and polycaprolactone itaconate

    NARCIS (Netherlands)

    Sharifi, Shahriar; Shafieyan, Yousef; Mirzadeh, Hamid; Bagheri-Khoulenjani, Shadab; Rabiee, Sayed Mahmood; Imani, Mohammad; Atai, Mohammad; Shokrgozar, Mohammad Ali; Hatampoor, Ali

    In this work, two unsaturated derivatives of polycaprolactone (PCL), polycaprolactone fumarate (PCLF), and polycaprolactone itaconate (PCLI), have been synthesized and used as an infiltrating polymer to improve the mechanical properties of brittle hydroxyapatite (HA) scaffolds. PCLF and PCLI were

  6. Physical characterization of hydroxyapatite porous scaffolds for tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, S., E-mail: smsilva@ineb.up.pt [INEB - Instituto de Engenharia Biomedica, Divisao de Biomateriais, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto (Portugal); Universidade do Porto, Faculdade de Engenharia, Departamento de Engenharia Metalurgica e Materiais, Porto (Portugal); Rodriguez, M.A.; Pena, P.; De Aza, A.H.; De Aza, S. [Instituto de Ceramica y Vidrio, CSIC, 28049-Cantoblanco, Madrid (Spain); Ferraz, M.P. [INEB - Instituto de Engenharia Biomedica, Divisao de Biomateriais, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto (Portugal); Faculdade de Ciencias da Saude da Universidade Fernando Pessoa, Rua Carlos da Maia, 296, 4200-150 Porto (Portugal); Monteiro, F.J. [INEB - Instituto de Engenharia Biomedica, Divisao de Biomateriais, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto (Portugal); Universidade do Porto, Faculdade de Engenharia, Departamento de Engenharia Metalurgica e Materiais, Porto (Portugal)

    2009-06-01

    The present study refers to the preparation and characterization of porous hydroxyapatite scaffolds to be used as matrices for bone regeneration or as specific release vehicles. Ceramics are widely used for bone tissue engineering purposes and in this study, hydroxyapatite porous scaffolds were produced using the polymer replication method. Polyurethane sponges were used as templates and impregnated with a ceramic slurry at different ratios, and sintered at 1300 deg. C following a specific thermal cycle. The characteristics of the hydroxyapatite porous scaffolds and respective powder used as starting material, were investigated by using scanning electron microscopy, particle size distribution, X-ray diffraction, Fourier transformed infrared spectroscopy and compressive mechanical testing techniques. It was possible to produce highly porous hydroxyapatite scaffolds presenting micro and macropores and pore interconnectivity.

  7. Fracture behavior of block copolymer and graphene nanoplatelet modified epoxy and fiber reinforced/epoxy polymer composites

    Science.gov (United States)

    Kamar, Nicholas T.

    Glass and carbon fiber reinforced/epoxy polymer composites (GFRPs and CFRPs) have high strength-to-weight and stiffness-to-weight ratios. Thus, GFRPs and CFRPs are used to lightweight aircraft, marine and ground vehicles to reduce transportation energy utilization and cost. However, GFRP and CFRP matrices have a low resistance to crack initiation and propagation; i.e. they have low fracture toughness. Current methods to increase fracture toughness of epoxy and corresponding GFRP and CFRPs often reduce composite mechanical and thermomechanical properties. With the advent of nanotechnology, new methods to improve the fracture toughness and impact properties of composites are now available. The goal of this research is to identify the fracture behavior and toughening mechanisms of nanoparticle modified epoxy, GFRPs and CFRPs utilizing the triblock copolymer poly(styrene)-block-poly(butadiene)-block-poly(methylmethacrylate) (SBM) and graphene nanoplatelets (GnPs) as toughening agents. The triblock copolymer SBM was used to toughen the diglycidyl ether of bisphenol-A (DGEBA) resin cured with m-phenylenediamine (mPDA) and corresponding AS4-12k CFRPs. SBM self assembled in epoxy to form nanostructured domains leading to larger increases in fracture toughness, KQ (MPa*m 1/2) than the traditional, phase separating carboxyl-terminated butadiene-acrylonitrile (CTBN) rubber. Additionally, SBM increased the mode-I fracture toughness, GIc (J/m2) of CFRPs without corresponding reductions in composite three-point flexural properties and glass transition temperature (Tg). Fractography of SBM modified epoxy and CFRPs via scanning electron microscopy (SEM) showed that sub 100 nm spherical micelles cavitated to induce void growth and matrix shear yielding toughening mechanisms. Furthermore, SBM did not suppress epoxy Tg, while CTBN decreased Tg with both increasing concentration and acrylonitrile content. Graphene nanoplatelets (GnPs) consist of a few layers of graphene sheets, which

  8. Bending and Shear Behavior of Pultruded Glass Fiber Reinforced Polymer Composite Beams With Closed and Open Sections

    Science.gov (United States)

    Estep, Daniel Douglas

    Several advantages, such as high strength-to-weight ratio, high stiffness, superior corrosion resistance, and high fatigue and impact resistance, among others, make FRPs an attractive alternative to conventional construction materials for use in developing new structures as well as rehabilitating in-service infrastructure. As the number of infrastructure applications using FRPs grows, the need for the development of a uniform Load and Resistance Factor Design (LRFD) approach, including design procedures and examples, has become paramount. Step-by-step design procedures and easy-to-use design formulas are necessary to assure the quality and safety of FRP structural systems by reducing the possibility of design and construction errors. Since 2008, the American Society of Civil Engineers (ASCE), in coordination with the American Composites Manufacturers Association (ACMA), has overseen the development of the Pre-Standard for Load and Resistance Factor Design (LRFD) of Pultruded Fiber Reinforced Polymer (FRP) Structures using probability-based limit states design. The fifth chapter of the pre-standard focuses on the design of members in flexure and shear under different failure modes, where the current failure load prediction models proposed within have been shown to be highly inaccurate based on experimental data and evaluation performed by researchers at the West Virginia University Constructed Facilities Center. A new prediction model for determining the critical flexural load capacity of pultruded GFRP square and rectangular box beams is presented within. This model shows that the type of failure can be related to threshold values of the beam span-to-depth ratio (L/h) and total flange width-to-thickness ratio (bf /t), resulting in three governing modes of failure: local buckling failure in the compression flange (4 ≤ L/h web-flange junction (6 ≤ L/h ≤ 10), and bending failure in the tension flange (10 < L/h ≤ 42). Broadly, the proposed equations are

  9. Effect of surface treatment of hydroxyapatite whiskers on the mechanical properties of bis-GMA-based composites

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Hongquan; Zhang Ming, E-mail: htmzhang@polyu.edu.h [Department of Health Technology and Informatics, Hong Kong Polytechnic University (Hong Kong)

    2010-10-01

    The mechanical properties of bis-GMA-based composites filled with hydroxyapatite (HA) particles or whiskers are characterized in this paper. The inherent properties of reinforcements, the bonding strength of the filler-matrix interface and their dispersibility in a polymer matrix were intimately associated with the mechanical performance of the composites. Silanization of both particles and whiskers effectively improved the bonding of the filler-matrix interface, their dispersibility in matrix monomers and filler loading. The particle- and whisker-filled composites showed highly significant differences in both flexural strength and fracture toughness. HA whiskers prepared by hydrothermal homogeneous precipitation had superior dispersibility and wettability in the polymer matrix; no aggregation and entanglement were found in both the products before and after silanization and the resin composites. These features conferred the whiskers having good interface bonding with the polymer matrix and superior reinforcing and toughening effects. For the particulate filler, the addition of HA led to a decrease in the flexural strength for both silane-treated and untreated fillers. Cracks propagated easily through the micropores and voids in the HA aggregates, leading to lower flexural strength and low toughness. However, silanization of HA did not show obvious effects on the elastic modulus of the composites.

  10. The Study of Thermal, Mechanical and Shape Memory Properties of Chopped Carbon Fiber-Reinforced TPI Shape Memory Polymer Composites

    National Research Council Canada - National Science Library

    Zhenqing Wang; Jingbiao Liu; Jianming Guo; Xiaoyu Sun; Lidan Xu

    2017-01-01

    Trans-l,4-polyisoprene (TPI) shape memory polymer composites with different chopped carbon fiber mass fractions were prepared to study the effects of different chopped carbon fiber mass fractions and temperatures on the TPI...

  11. A new biotechnology for articular cartilage repair: subchondral implantation of a composite of interconnected porous hydroxyapatite, synthetic polymer (PLA-PEG), and bone morphogenetic protein-2 (rhBMP-2).

    Science.gov (United States)

    Tamai, Noriyuki; Myoui, Akira; Hirao, Makoto; Kaito, Takashi; Ochi, Takahiro; Tanaka, Junzo; Takaoka, Kunio; Yoshikawa, Hideki

    2005-05-01

    Articular cartilage repair remains a major obstacle in tissue engineering. We recently developed a novel tool for articular cartilage repair, consisting of a triple composite of an interconnected porous hydroxyapatite (IP-CHA), recombinant human bone morphogenetic protein-2 (rhBMP-2), and a synthetic biodegradable polymer [poly-d,l-lactic acid/polyethylene glycol (PLA-PEG)] as a carrier for rhBMP-2. In the present study, we evaluated the capacity of the triple composite to induce the regeneration of articular cartilage. Full-thickness cartilage defects were created in the trochlear groove of 52 New Zealand White rabbits. Sixteen defects were filled with the bone morphogenetic protein (BMP)/PLA-PEG/IP-CHA composite (group I), 12 with PLA-PEG/IP-CHA (group II), 12 with IP-CHA alone (group III), and 12 were left empty (group IV). The animals were killed 1, 3, and 6 weeks after surgery, and the gross appearance of the defect sites was assessed. The harvested tissues were examined radiographically and histologically. One week after implantation with the BMP/PLA-PEG/IP-CHA composite (group I), vigorous repair had occurred in the subchondral defect. It contained an agglomeration of mesenchymal cells which had migrated from the surrounding bone marrow either directly, or indirectly via the interconnecting pores of the IP-CHA scaffold. At 6 weeks, these defects were completely repaired. The regenerated cartilage manifested a hyaline-like appearance, with a mature matrix and a columnar organization of chondrocytes. The triple composite of rhBMP-2, PLA-PEG, and IP-CHA promotes the repair of full-thickness articular cartilage defects within as short a period as 3 weeks in the rabbit model. Hence, this novel cell-free implant biotechnology could mark a new development in the field of articular cartilage repair.

  12. Electrical conductivity, dielectric response and space charge dynamics of an electroactive polymer with and without nanofiller reinforcement

    Science.gov (United States)

    Kochetov, R.; Tsekmes, I. A.; Morshuis, P. H. F.

    2015-07-01

    Electroactive polymers have gained considerable attention over the last 20 years for exhibiting a large displacement in response to electrical stimulation. The promising fields of application include wave energy converters, muscle-like actuators, sensors, robotics, and biomimetics. For an electrical engineer, electroactive polymers can be seen as a dielectric elastomer film or a compliant capacitor with a highly deformable elastomeric medium. If the elastomer is pre-stretched and pre-charged, a reduction of the tensile force lets the elastomer revert to its original form and increases the electrical potential. The light weight of electroactive polymers, low cost, high intrinsic breakdown strength, cyclical way of operation, reliable performance, and high efficiency can be exploited to utilize the elastomeric material as a transducer. The energy storage for a linear dielectric polymer is determined by its relative permittivity and the applied electric field. The latter is limited by the dielectric breakdown strength of the material. Therefore, to generate a high energy density of a flexible capacitor, the film must be used at the voltage level close to the material’s breakdown or inorganic particles with high dielectric permittivity which can be introduced into the polymer matrix. In the present study, silicone-titania elastomer nanocomposites were produced and the influence of nanoparticles on the macroscopic dielectric properties of the neat elastomer including space charge dynamics, complex permittivity, and electrical conductivity, were investigated.

  13. Time dependence of mesoscopic strain distribution for triaxial woven carbon-fiber-reinforced polymer under creep loading measured by digital image correlation

    Science.gov (United States)

    Koyanagi, Jun; Nagayama, Hideo; Yoneyama, Satoru; Aoki, Takahira

    2016-06-01

    This paper presents the time dependence of the mesoscopic strain of a triaxial woven carbon-fiber-reinforced polymer under creep loading measured using digital image correlation (DIC). Two types of DIC techniques were employed for the measurement: conventional subset DIC and mesh DIC. Static tensile and creep tests were carried out, and the time dependence of the mesoscopic strain distribution was investigated by applying these techniques. The ultimate failure of this material is dominated by inter-bundle decohesion caused by relative rigid rotation and relating shear stress. Therefore, these were focused on in the present study. During the creep tests, the fiber directional strain, shear strain, and rotation were monitored using the DIC, and the mechanism for the increase in the specimen's macro-strain over time was investigated based on the results obtained by the DIC measurement.

  14. Influence of Layup and Curing on the Surface Accuracy in the Manufacturing of Carbon Fiber Reinforced Polymer (CFRP) Composite Space Mirrors

    Science.gov (United States)

    Yang, Zhiyong; Zhang, Jianbao; Xie, Yongjie; Zhang, Boming; Sun, Baogang; Guo, Hongjun

    2017-03-01

    Carbon fiber reinforced polymer, CFRP, composite materials have been used to fabricate space mirror. Usually the composite space mirror can completely replicate the high-precision surface of mould by replication process, but the actual surface accuracy of replicated space mirror is always reduced, still needed further study. We emphatically studied the error caused by layup and curing on the surface accuracy of space mirror through comparative experiments and analyses, the layup and curing influence factors include curing temperature, cooling rate of curing, method of prepreg lay-up, and area weight of fiber. Focusing on the four factors, we analyzed the error influence rule and put forward corresponding control measures to improve the surface figure of space mirror. For comparative analysis, six CFRP composite mirrors were fabricated and surface profile of mirrors were measured. Four guiding control measures were described here. Curing process of composite space mirror is our next focus.

  15. Short fiber reinforced thermoplastic blends

    NARCIS (Netherlands)

    Malchev, P.G.

    2008-01-01

    The present thesis investigates the potential of short fiber reinforced thermoplastic blends, a combination of an immiscible polymer blend and a short fiber reinforced composite, to integrate the easy processing solutions available for short fiber reinforced composites with the high mechanical

  16. Multi-Length Scale-Enriched Continuum-Level Material Model for Kevlar®-Fiber-Reinforced Polymer-Matrix Composites

    Science.gov (United States)

    Grujicic, M.; Pandurangan, B.; Snipes, J. S.; Yen, C.-F.; Cheeseman, B. A.

    2013-03-01

    Fiber-reinforced polymer matrix composite materials display quite complex deformation and failure behavior under ballistic/blast impact loading conditions. This complexity is generally attributed to a number of factors such as (a) hierarchical/multi-length scale architecture of the material microstructure; (b) nonlinear, rate-dependent and often pressure-sensitive mechanical response; and (c) the interplay of various intrinsic phenomena and processes such as fiber twisting, interfiber friction/sliding, etc. Material models currently employed in the computational engineering analyses of ballistic/blast impact protective structures made of this type of material do not generally include many of the aforementioned aspects of the material dynamic behavior. Consequently, discrepancies are often observed between computational predictions and their experimental counterparts. To address this problem, the results of an extensive set of molecular-level computational analyses regarding the role of various microstructural/morphological defects on the Kevlar® fiber mechanical properties are used to upgrade one of the existing continuum-level material models for fiber-reinforced composites. The results obtained show that the response of the material is significantly affected as a result of the incorporation of microstructural effects both under quasi-static simple mechanical testing condition and under dynamic ballistic-impact conditions.

  17. Preparation and characterization of corn reinforced polymer sheet of fibers; Obtencao e caracterizacao de polimero reforcado com fibras da folha de milho

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Tatiana Martinez; Seo, Emilia Satoshi Miyamaru, E-mail: tatianaltda@hotmail.com, E-mail: esmiyseo@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2016-10-15

    There is a global trend in seeking plant fibers to replace the synthetic fibers to obtain reinforced composites aimed at the use of renewable resources. In this context, this paper aims to develop the process of preparing maize leaf fibers, characterizing them and adapting them for applications in the construction industry and develop a reinforced polymer composite with these fibers. Corn leaves were dried in environmental temperature, treated by mercerizing, then neutralized with acid solution and washed in running water. The characterization of the corn leaf fibers was carried out by X-ray diffraction, X-ray fluorescence, scanning electron microscopy, specific surface area, thermogravimetry and specific mass. The mercerizing treatment was effective, because the maize fibers have characteristics similar to synthetic fibers, leading to a possibility of new technological uses. The polymeric composite material was developed by extrusion processes and injection and tested for tensile testing, differential scanning calorimetry and scanning electron microscopy, thus reused an organic waste that would be disposed of by inserting it in a technological process, contributing to the research and development of new polymeric materials as well as to reduce waste discarded as scrap. (author)

  18. Implementation of a finite element analysis procedure for structural analysis of shape memory behaviour of fibre reinforced shape memory polymer composites

    Science.gov (United States)

    Azzawi, Wessam Al; Epaarachchi, J. A.; Islam, Mainul; Leng, Jinsong

    2017-12-01

    Shape memory polymers (SMPs) offer a unique ability to undergo a substantial shape deformation and subsequently recover the original shape when exposed to a particular external stimulus. Comparatively low mechanical properties being the major drawback for extended use of SMPs in engineering applications. However the inclusion of reinforcing fibres in to SMPs improves mechanical properties significantly while retaining intrinsic shape memory effects. The implementation of shape memory polymer composites (SMPCs) in any engineering application is a unique task which requires profound materials and design optimization. However currently available analytical tools have critical limitations to undertake accurate analysis/simulations of SMPC structures and slower derestrict transformation of breakthrough research outcomes to real-life applications. Many finite element (FE) models have been presented. But majority of them require a complicated user-subroutines to integrate with standard FE software packages. Furthermore, those subroutines are problem specific and difficult to use for a wider range of SMPC materials and related structures. This paper presents a FE simulation technique to model the thermomechanical behaviour of the SMPCs using commercial FE software ABAQUS. Proposed technique incorporates material time-dependent viscoelastic behaviour. The ability of the proposed technique to predict the shape fixity and shape recovery was evaluated by experimental data acquired by a bending of a SMPC cantilever beam. The excellent correlation between the experimental and FE simulation results has confirmed the robustness of the proposed technique.

  19. Hydroxyapatite synthesis using EDTA

    Science.gov (United States)

    Kang, Nak Heon; Kim, Soon Je; Song, Seung Han; Choi, Sang mun; Choi, Sik Young; Kim, Youn Jung

    2013-01-01

    Bone comprises structure of body and is consisted of inorganic substances. It exists in an organic structure in the body. Even though it is firm and has self healing mechanism, it can be damaged by trauma, cancer, or bone diseases. Allograft can be an alternative solution for autologous bone graft. Hydroxyapatite(Ca10(PO4)6(OH)2), an excellent candidate for allograft, can be applied to bone defect area. There are several methods to produce hydroxyapatite, however economical cost and time consuming make the production difficult. In this study we synthesized the hydroxyapatite with Ethyenediamine tetraacetic acid. Freeze Dried Bone Allograft(Hans Biomed) was used to be a control group. Synthesized hydroxyapatite was a rod shape, white powdery type substance with 2 ~ 5 μm length and 0.5 ~ 1 μm width. X-ray diffraction showed the highest sharp peak at 32° and high peaks at 25.8°, 39.8°, 46.8°, 49.5°, and 64.0° indicating a similar substance to the freeze Dried Bone Allograft. 3 days after the cell growth of synthesized hydroxyapatite showed 1.5 fold more than the Bone Allograft. Cellular and media alkaline phosphate activity increased similar to the bone alloagraft. In this study we came up with a new method to produce the hydroxyapatite. It is a convenient method that can be held in room temperature and low pressure. Also the the product can be manufactured in large quantity. It can be also transformed into scaffold structure which will perform a stronger configuration. The manufacturing method will help the bony defect patients and make future medical products. PMID:23714942

  20. Particulate Composite Materials: Numerical Modeling of a Cross-Linked Polymer Reinforced With Alumina-Based Particles

    Science.gov (United States)

    Máša, B.; Náhlík, L.; Hutař, P.

    2013-09-01

    The macroscopic mechanical properties of a particulate composite under uniaxial tensile loading have been estimated. The composite studied consisted of a polymer matrix in a rubbery state (polymethylmethacrylate - PMMA) and alumina-based particles (Al2O3). A numerical modeling by using the finite-element method (FEM) was performed to determine the stress-strain behavior of the particulate composite. The numerical simulation took into account the hyperelastic properties of the cross-linked polymer matrix, which was described by the three-parameter Mooney-Rivlin material model. A representative volume element (RVE) was chosen for FE analyses to model the microstructure of the composite. Various compositions of particles and their different shape and orientation were considered in the study. Various directions of loading of the RVE were also investigated. A progressive damage model was implemented into the numerical models. The mechanical characteristics obtained from computations, which included the damage model, were compared with experimental data, and a good agreement has been found to exist between them. The procedure presented can be used for estimating the mechanical properties of new particulate composites with a cross-linked polymer matrix, and it also contributes to the clarification of damage development and failure in composites of the type studied.

  1. Behavior of reinforced concrete beams reinforced with GFRP bars

    Directory of Open Access Journals (Sweden)

    D. H. Tavares

    Full Text Available The use of fiber reinforced polymer (FRP bars is one of the alternatives presented in recent studies to prevent the drawbacks related to the steel reinforcement in specific reinforced concrete members. In this work, six reinforced concrete beams were submitted to four point bending tests. One beam was reinforced with CA-50 steel bars and five with glass fiber reinforced polymer (GFRP bars. The tests were carried out in the Department of Structural Engineering in São Carlos Engineering School, São Paulo University. The objective of the test program was to compare strength, reinforcement deformation, displacement, and some anchorage aspects between the GFRP-reinforced concrete beams and the steel-reinforced concrete beam. The results show that, even though four GFRP-reinforced concrete beams were designed with the same internal tension force as that with steel reinforcement, their capacity was lower than that of the steel-reinforced beam. The results also show that similar flexural capacity can be achieved for the steel- and for the GFRP-reinforced concrete beams by controlling the stiffness (reinforcement modulus of elasticity multiplied by the bar cross-sectional area - EA and the tension force of the GFRP bars.

  2. Characterization and dynamic mechanical analysis of selective laser sintered hydroxyapatite-filled polymeric composites.

    Science.gov (United States)

    Zhang, Y; Hao, L; Savalani, M M; Harris, R A; Tanner, K E

    2008-09-01

    Selective laser sintering (SLS) is a manufacturing technique which enables the final product to be made directly and rapidly, without tooling or additional machining. For biomedical applications, SLS permits the fabrication of implants and scaffolds with complex geometry accurately and economically. In this study, hydroxyapatite-reinforced polyethylene and polyamide composites were fabricated using SLS. The SLS samples were characterized in terms of their internal structure, morphology, and porosity. The mechanical properties were examined by dynamic mechanical analysis. The effects of SLS processing conditions, including particle size and laser power, were investigated, and the results were compared with conventional compression-molded and machined specimens. The internal structure of sintered samples was porous, with open interconnected pores, and the pore size was up to 200 microm. Particle size and laser energy play a key role in the final density and mechanical properties of the sintered components. In the parameter range used, the use of smaller particles produced higher density and stiffness, and the laser-induced energy could also be varied to optimize the manufacturing process. This study demonstrated that high-HA-content reinforced polymer composite can be successfully manufactured by SLS with controlled porosity features.

  3. REVIEW OF STRENGTHENING REINFORCED CONCRETE BEAMS USING CFRP LAMINATE

    OpenAIRE

    SAGATOV BAHODIR UKTAMOVICH; SHODMONOV ANARQUL YULDASHEVICH; ALIYEV MASHRAB RAHMONQULOVICH; DJURAYEV UKTAM URALBAYEVICH

    2016-01-01

    This paper presents the Literature Review of carbon fiber reinforced polymer (CFRP) strips to reinforced concrete (RC) as a strengthening solution for T-beams. Although a great deal of research has been carried out on Rectangular beams strengthened with Fibre-Reinforced Polymer composites (FRP), Fiber reinforced polymer (FRP) composites have been increasingly studied for their application in the flexural or shear strengthening of reinforced concrete (RC) members. A detailed discussion of the ...

  4. In-situ solvothermal processing of polycaprolactone/hydroxyapatite nanocomposites with enhanced mechanical and biological performance for bone tissue engineering

    Directory of Open Access Journals (Sweden)

    Saeed Moeini

    2017-09-01

    Full Text Available The interest in biodegradable polymer-matrix nanocomposites with bone regeneration potential has been increasing in recent years. In the present work, a solvothermal process is introduced to prepare hydroxyapatite (HA nanorod-reinforced polycaprolactone in-situ. A non-aqueous polymer solution containing calcium and phosphorous precursors is prepared and processed in a closed autoclave at different temperatures in the range of 60–150 °C. Hydroxyapatite nanorods with varying aspect ratios are formed depending on the processing temperature. X-ray diffraction analysis and field-emission scanning electron microscopy indicate that the HA nanorods are semi-crystalline. Energy-dispersive X-ray spectroscopy and Fourier transform infrared spectrometry determine that the ratio of calcium to phosphorous increases as the processing temperature increases. To evaluate the effect of in-situ processing on the mechanical properties of the nanocomposites, highly porous scaffolds (>90% containing HA nanorods are prepared by employing freeze drying and salt leaching techniques. It is shown that the elastic modulus and strength of the nanocomposites prepared by the in-situ method is superior (∼15% to those of the ex-situ samples (blended HA nanorods with the polymer solution. The enhanced bone regeneration potential of the nanocomposites is shown via an in vitro bioactivity assay in a saturated simulated body fluid. An improved cell viability and proliferation is also shown by employing (3-(4,5- dimethylthiazol-2-yl-2, 5-diphenyl tetrazolium bromide (MTT assay in human osteosarcoma cell lines. The prepared scaffolds with in vitro regeneration capacity could be potentially useful for orthopaedic applications and maxillofacial surgery.

  5. Multiscale modeling of the effect of carbon nanotube orientation on the shear deformation properties of reinforced polymer-based composites

    Science.gov (United States)

    Montazeri, A.; Sadeghi, M.; Naghdabadi, R.; Rafii-Tabar, H.

    2011-04-01

    A combination of molecular dynamics (MD), continuum elasticity and FEM is used to predict the effect of CNT orientation on the shear modulus of SWCNT-polymer nanocomposites. We first develop a transverse-isotropic elastic model of SWCNTs based on the continuum elasticity and MD to compute the transverse-isotropic elastic constants of SWCNTs. These constants are then used in an FEM-based simulation to investigate the effect of SWCNT alignment on the shear modulus of nanocomposites. Furthermore, shear stress distributions along the nanotube axis and over its cross-sectional area are investigated to study the effect of CNT orientation on the shear load transfer.

  6. Long-term performance of GFRP reinforcement : technical report.

    Science.gov (United States)

    2009-12-01

    Significant research has been performed on glass fiber-reinforced polymer (GFRP) concrete reinforcement. : This research has shown that GFRP reinforcement exhibits high strengths, is lightweight, can decrease time of : construction, and is corrosion ...

  7. Nanoclays reinforced glass ionomer cements: dispersion and interaction of polymer grade (PG) montmorillonite with poly(acrylic acid).

    Science.gov (United States)

    Fareed, Muhammad A; Stamboulis, Artemis

    2014-01-01

    Montmorillonite nanoclays (PGV and PGN) were dispersed in poly(acrylic acid) (PAA) for utilization as reinforcing filler in glass ionomer cements (GICs). Chemical and physical interaction of PAA and nanoclay (PGV and PGN) was studied. PAA–PGV and PAA–PGN solutions were prepared in different weight percent loadings of PGV and PGN nanoclay (0.5-8.0 wt%) via exfoliation-adsorption method. Characterization was carried out by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and fourier transform infrared (FTIR) spectroscopy. XRD results of PAA–PGN demonstrated that the interlayer space expanded from 12.83 to 16.03 Å indicating intercalation whereas the absence of the peak at d(001) in PAA–PGV indicated exfoliation. XPS scans of PGV and PGN nanoclays depicted the main peak of O 1s photoelectron due to Si–O–M (M = Mg, Al, Fe) whereas, Si–O–Al linkages were identified by Si 2p or Si 2s and Al 2p or Al 2s peaks. The disappearance of the Na peak confirmed that PAA molecules exchanged sodium ions present on surface of silicate layers and significantly reduced the electrostatic van-der-Waals forces between silicate plates resulting in intercalation or exfoliation. FTIR spectra of PAA–nanoclay suspensions demonstrated the presence of a new peak at 1,019 cm(-1) associated with Si–O– stretching vibrations which increased with increasing nanoclays concentration. Information concerning the dispersion of nanoclay in PAA aqueous solutions, chemical reaction and increase interlayer space in montmorillonite nanoclay is particularly useful regarding dispersion and reinforcement of nanoclay in PAA.

  8. Study of the reflective behaviour of carbon fibres reinforced polymer composite up to 450°C

    Science.gov (United States)

    Le Louët, Violaine; Rousseau, Benoit; Le Corre, Steven; Boyard, Nicolas; Tardif, Xavier; Delmas, Jérôme; Delaunay, Didier

    2017-10-01

    This study aims at characterizing the radiative properties of a carbon/PEEK composite, a material known to be opaque for usual thicknesses and to scatter thermal radiation in the infrared spectral range. The scattering behaviour is probed here at room temperature with a variable angle reflectivity unit linked to a Fourier Transform InfraRed Spectrometer (0.6-25 µm), for different fibre orientations and various angles of incidence. Moreover, in order to study the influence of temperature, particularly of the polymer matrix melting, a compact cell, based on a customized resistive heater, is adapted to the sample compartment of the spectrometer to measure the thermal dependency of the normal reflectivity. The new sample holder can be used at a temperature ranging between 20 and 450°C and with a temperature stability lower than 0.1 K. For the carbon/PEEK composite, the effects of the polymer phase change are observed to be small, confirming the predominant role of carbon on those composites optical properties.

  9. Obtention and dynamical mechanical behavior of polymer matrix carbon fire reinforced composites; Obtencao e comportamento mecanodinamico de compositos com matriz polimerica reforcada com fibras de carbono

    Energy Technology Data Exchange (ETDEWEB)

    Da Silva, Nelson Marques

    2001-07-01

    Polymer matrix composites reinforced with carbon fibres have been extensively used in the nuclear, aeronautics, automotive and leisure industry. This is due to their superior performance when compared to conventional materials in terms of specific strength and specific modulus (3 to 4 times higher than that of mild steels). However, these materials are anisotropic, requiring characterisation for each process and particular application. In the present work, the evaluation of epoxy resin reinforced with unidirectional and continuous carbon fibres was carried out. The composites materials were obtained by filament winding, with three different cure cycles, with two types of carbon fibres (6000 and 12000 filaments per strand) and with fibres volumetric fraction around 60 %. The evaluation of the composites was undertaken using following techniques: scanning electron microscopy (SEM); dynamic mechanical analysis (DMA); thermogravimetric analysis (TGA), and differential scanning calorimeter (DSC). These techniques allowed the evaluation and comparison of storage modulus, internal energy dissipation, glass transition region and glass transition temperature - Tg, cure cycling. Besides, void volumetric fraction was measured. The results indicate that the DMA is a good alternative technique to DSC and TGA. It provides an indication of the quality of the produced composite, both thermal and mechanical. The technique can assist the quality control of composite components by measuring mechanical and thermal properties - modulus and Tg. The DMA technique was sensitive to cure cycling evaluation. Regarding the obtained composites, the results showed the need for the development of specific cure cycle for each application, establishing a compromise between properties such as storage modulus and internal energy dissipation, and involved costs. The results demonstrated differences between the storage modulus and internal energy dissipation for the two types of used fibres. (author)

  10. Investigation of Mechanical and Thermal Properties of Polymer Composites Reinforced by Multi-Walled Carbon Nanotube for Reduction of Residual Stresses

    Directory of Open Access Journals (Sweden)

    Ahmad Reza Ghasemi

    2014-08-01

    Full Text Available The micromechanical models are used to investigate mechanical and thermal properties of a polymer matrix nanocomposite containing multi-walled carbon nanotubes (MWCNT in their effects to reduce residual stresses in nanocomposites. To do this, first nanotubes with different weights and volume fractions were dispersed in ML-506 epoxy resin. By using different micromechanical models, the effect additional nanotubes on elastic modulus and coefficient of thermal expansion (CTE of nanotubes/epoxy were studied as critical parameters. Comparing the model and available experimental results, the modified Halpin-Tsai model and the modified Schapery model were chosen to calculate the mechanical and thermal properties of the nanocomposites. Then, using the matrix reinforced with MWCNT and classical micromechanics models the elastic modulus and coefficients of thermal expansion of the nanocomposites were determined for a single orthotropic ply. The results showed that the rule of mixture (ROM and Hashin-Rosen model to determine the longitudinal and transverse elastic moduli and Van Fo Fy model to calculate the coefficient of thermal expansion were in good agreements with the experimental results of a single-layer nanocomposite. Finally, the classical laminated plate theory (CLPT was used to calculate the residual stresses of the CNT/carbon fiber/epoxy composites with different weights and volume fractions of MWCNT for angle-ply, cross-ply and quasi-isotropic laminated composite materials. The results showed that residual stresses were reduced using a maximum of 1% wt or 0.675% volume fraction of the MWCNT in polymer composites. Also, the highest reduction in residual stresses was observed in [02/902] cross-ply laminated composite materials.

  11. Hydroxyapatite coatings for biomedical applications

    CERN Document Server

    Zhang, Sam

    2013-01-01

    Hydroxyapatite coatings are of great importance in the biological and biomedical coatings fields, especially in the current era of nanotechnology and bioapplications. With a bonelike structure that promotes osseointegration, hydroxyapatite coating can be applied to otherwise bioinactive implants to make their surface bioactive, thus achieving faster healing and recovery. In addition to applications in orthopedic and dental implants, this coating can also be used in drug delivery. Hydroxyapatite Coatings for Biomedical Applications explores developments in the processing and property characteri

  12. CNTs, Al2O3 and SiO2 Reinforced Epoxy: Tribological Properties of Polymer Nanocomposites

    Directory of Open Access Journals (Sweden)

    M.A. Ramadan,

    2017-09-01

    Full Text Available The present work studied the effect of filling epoxy matrix by different types and concentrations of nanoparticles on the friction and wear behaviors. Various concentrations (0.2 %, 0.4 %, 0.6 %, 0.8 % and 1 wt.% of multi walled carbon nano tubes (MWCNTs, aluminum oxide (Al2O3, and silica (SiO2 nanoparticles were used to reinforce epoxy matrix. These epoxy nanocomposites are widely used as indoor flooring tiles in schools, boutiques, hospitals, offices, conference rooms, homes, trade fair stands and homes for the aged. Experiments involved sliding of the epoxy nanocomposite specimens against rotating steel disc at dry sliding condition. Experiments were carried out using a test rig of pin-on-disc, designed and manufactured for the test. The friction force was measured using load cell which connected with a digital screen to detect the friction force. All experiments were done at room temperature and carried out at constant normal load (7 N, constant speed (0.93 m/sec and constant running time (300 seconds. The worn surfaces were investigated with back scattered scanning electron microscopy (SEM. Based on the observations in the present work, it was found that addition of the tested filling nanoparticles have greatly affected the friction and highly improves wear resistance.

  13. Mechanical characterization of a short fiber-reinforced polymer at room temperature: experimental setups evaluated by an optical measurement system

    Science.gov (United States)

    Röhrig, C.; Scheffer, T.; Diebels, S.

    2017-09-01

    Composite materials are of great interest for industrial applications because of their outstanding properties. Each composite material has its own characteristics due to the large number of possible combinations of matrix and filler. As a result of their compounding, composites usually show a complex material behavior. This work is focused on the experimental testing of a short fiber-reinforced thermoplastic composite at room temperature. The characteristic behavior of this material class is often based on a superposition of typical material effects. The predicted characteristic material properties such as elasto-plasticity, damage and anisotropy of the investigated material are obtained from results of cyclic uniaxial tensile tests at constant strain rate. Concerning the manufacturing process as well as industrial applications, the experimental investigations are extended to multiaxial loading situations. Therefore, the composite material is examined with a setup close to a deep-drawing process, the Nakajima test (Nakazima et al. in Study on the formability of steel sheets. Yawate Technical Report No. 264, pp 8517-8530, 1968). The evaluation of the experimental investigations is provided by an optical analysis system using a digital image correlation software. Finally, based on the results of the uniaxial tensile tests, a one-dimensional macroscopic model is introduced and first results of the simulation are provided.

  14. Assessing the Environmental Impact of Flax Fibre Reinforced Polymer Composite from a Consequential Life Cycle Assessment Perspective

    Directory of Open Access Journals (Sweden)

    Yelin Deng

    2015-08-01

    Full Text Available The study implements the consequential life cycle assessment (CLCA to provide a market based perspective on how overall environmental impact will change when shifting glass fibres to flax fibres as reinforcements in composite fabrication. With certain assumptions, the marginal flax fibre supply is identified to be a combination of Chinese flax fibre (70% and French flax fibre (30%. Due to inferior cultivars and coal-fired electricity in Chinese flax cultivation, the CLCA study reveals that flax mat-PP has 0.8–2 times higher environmental impact values than the glass mat-PP in most environmental impact categories over the production and end-of-life (EoL phases. For purpose of providing potential trajectories of marginal flax fibre supply, additional scenarios: the “all French fibre”, and “all Chinese fibre” are evaluated formulating the lower and upper boundaries in terms of environmental impact change, respectively. A “the attributional fibre supply mix” scenario is supplied as well. All of these scenarios are useful for policy analysis.

  15. The Effects of Fiber Orientation and Adhesives on Tensile Properties of Carbon Fiber Reinforced Polymer Matrix Composite with Embedded Nickel-Titanium Shape Memory Alloys

    Science.gov (United States)

    Quade, Derek J.; Jana, Sadhan C.; Morscher, Gregory N.; Kannan, Manigandan; McCorkle, Linda S.

    2017-01-01

    Nickel-titanium (NiTi) shape memory alloy (SMA) sections were embedded within carbon fiber reinforced polymer matrix composite (CFRPPMC) laminates and their tensile properties were evaluated with simultaneous monitoring of modal acoustic emissions. The test specimens were fabricated in three different layup configurations and two different thin film adhesives were applied to bond the SMA with the PMC. A trio of acoustic sensors were attached to the specimens during tensile testing to monitor the modal acoustic emission (AE) as the materials experienced mechanical failure. The values of ultimate tensile strengths, strains, and moduli were obtained. Cumulative AE energy of events and specimen failure location were determined. In conjunction, optical and scanning electron microscopy techniques were used to examine the break areas of the specimens. The analysis of AE data revealed failure locations within the specimens which were validated from the microscopic images. The placement of 90 deg plies in the outer ply gave the strongest acoustic signals during break as well as the cleanest break of the samples tested. Overlapping 0 deg ply layers surrounding the SMA was found to be the best scenario to prevent failure of the specimen itself.

  16. EVITA Project: Comparison Between Traditional Non-Destructive Techniques and Phase Contrast X-Ray Imaging Applied to Aerospace Carbon Fibre Reinforced Polymer

    Science.gov (United States)

    Gresil, Matthieu; Revol, Vincent; Kitsianos, Konstantinos; Kanderakis, Georges; Koulalis, Ilias; Sauer, Marc-Olivier; Trétout, Hervé; Madrigal, Ana-Maria

    2017-04-01

    The EU-project EVITA (Non-Destructive EValuation, Inspection and Testing of Primary Aeronautical Composite Structures Using Phase Contrast X-Ray Imaging) aims at bringing Grating-based Phase Contrast X-ray imaging technology to Non-Destructive Evaluation and Inspection of advanced primary and/or complex aerospace composite structures. Grating-based Phase Contrast X-Ray Imaging is based on the so-called Talbot-Lau interferometer, which is made of the combination of a standard X-ray apparatus with three transmission gratings as documented in the literature. This paper presents a comparison of two traditional non-destructive techniques (NDT): ultrasonic through transmission (immersed and water jet) and ultrasonic phased-array pulse echo, with the developed phase contrast X-Ray Imaging applied to advanced aerospace carbon fibre reinforced polymer. Typical defects produced during manufacture is examined as part of the testing and validation procedure. The following defects have been identified as being those most likely to be detected more effectively by the Grating-based Phase Contrast X-Ray Imaging process than other state of the art industrial NDT techniques: porosity, foreign objects, cracks, resin rich, cut fibres, and wavy fibres. The introduction of this innovative methodology is expected to provide the aeronautical industry with a reliable and detailed insight of the integrity of thin and thick composite structures as well as of complex geometry ones, such as integrated closed boxes and sandwiches.

  17. Machinability study of Carbon Fiber Reinforced Polymer in the longitudinal and transverse direction and optimization of process parameters using PSO–GSA

    Directory of Open Access Journals (Sweden)

    K. Shunmugesh

    2016-09-01

    Full Text Available Carbon Fiber Reinforced Polymer (CFRP composites are widely used in aerospace industry in lieu of its high strength to weight ratio. This study is an attempt to evaluate the machinability of Bi-Directional Carbon Fiber–Epoxy composite and optimize the process parameters of cutting speed, feed rate and drill tool material. Machining trials were carried using drill bits made of high speed steel, TiN and TiAlN at different cutting speeds and feed rates. Output parameters of thrust force and torque were monitored using Kistler multicomponent dynamometer 9257B and vibrations occurring during machining normal to the work surface were measured by a vibration sensor (Dytran 3055B. Linear regression analysis was carried out by using Response Surface Methodology (RSM, to correlate the input and output parameters in drilling of the composite in the longitudinal and transverse directions. The optimization of process parameters were attempted using Genetic Algorithm (GA and Particle Swarm Optimization–Gravitational Search Algorithm (PSO–GSA techniques.

  18. Cross-Sectional Unification on the Stress-Strain Model of Concrete Subjected to High Passive Confinement by Fiber-Reinforced Polymer

    Directory of Open Access Journals (Sweden)

    Yu-Gui Cao

    2016-05-01

    Full Text Available The stress-strain behavior of concrete can be improved by providing a lateral passive confining pressure, such as fiber-reinforced polymer (FRP wrapping. Many axial stress-strain models have been proposed for FRP-confined concrete columns. However, few models can predict the stress-strain behavior of confined concrete columns with more than two specified cross-sections. A stress-strain model of FRP-confined concrete columns with cross-sectional unification was developed in this paper based on a database from the existing literature that includes circular, square, rectangular and elliptical concrete columns that are highly confined by FRP jackets. Using the database, the existing theoretical models were evaluated. In addition, the ultimate stress and strain models with cross-sectional unification were proposed using two parameters: the cross-sectional aspect ratio and corner radius ratio. The elliptical cross-section can be considered as a rectangular one with a special corner radius for the model calculations. A simple and accurate model of the equivalent corner radius ratio for elliptical columns was proposed. Compared to the other existing models and experimental data, the proposed models show good performance.

  19. Finite strain anisotropic elasto-plastic model for the simulation of the forming and testing of metal/short fiber reinforced polymer clinch joints at room temperature

    Science.gov (United States)

    Dean, A.; Rolfes, R.; Behrens, A.; Bouguecha, A.; Hübner, S.; Bonk, C.; Grbic, N.

    2017-10-01

    There is a strong trend in the automotive industry to reduce car body-, chassis- and power-train mass in order to lower carbon emissions. More wide spread use of lightweight short fiber reinforced polymer (SFRP) is a promising approach to attain this goal. This poses the challenge of how to integrate new SFRP components by joining them to traditional sheet metal structures. Recently (1), the clinching technique has been successfully applied as a suitable joining method for dissimilar material such as SFRP and Aluminum. The material pairing PA6GF30 and EN AW 5754 is chosen for this purpose due to their common application in industry. The current contribution presents a verification and validation of a finite strain anisotropic material model for SFRP developed in (2) for the FE simulation of the hybrid clinching process. The finite fiber rotation during forming and separation, and thus the change of the preferential material direction, is represented in this model. Plastic deformations in SFRP are considered in this model via an invariant based non-associated plasticity formulation following the multiplicative decomposition approach of the deformation gradient where the stress-free intermediate configuration is introduced. The model allows for six independent characterization curves. The aforementioned material model allows for a detailed simulation of the forming process as well as a simulative prediction of the shear test strength of the produced joint at room temperature.

  20. Artifacts in spine magnetic resonance imaging due to different intervertebral test spacers: an in vitro evaluation of magnesium versus titanium and carbon-fiber-reinforced polymers as biomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Ernstberger, Thorsten [Klinikum Bad Bramstedt, Center for Spinal Surgery, Bad Bramstedt (Germany); Buchhorn, Gottfried [University of Gottingen, Biomaterial Laboratory, Department of Orthopedic Surgery, Goettingen (Germany); Heidrich, Gabert [University of Gottingen, Department of Diagnostic Radiology, Goettingen (Germany)

    2009-08-15

    Intervertebral spacers are made of different materials, which can affect the postfusion magnetic imaging (MRI) scans. Susceptibility artifacts especially for metallic implants can decrease the image quality. This study aimed to determine whether magnesium as a lightweight and biocompatible metal is suitable as a biomaterial for spinal implants based on its MRI artifacting behavior. To compare artifacting behaviors, we implanted into one porcine cadaveric spine different test spacers made of magnesium, titanium, and carbon-fiber-reinforced polymers (CFRP). All test spacers were scanned using two T1-TSE MRI sequences. The artifact dimensions were traced on all scans and statistically analyzed. The total artifact volume and median artifact area of the titanium spacers were statistically significantly larger than magnesium spacers (p < 0.001), while magnesium and CFRP spacers produced almost identical artifacting behaviors (p > 0.05). Our results suggest that spinal implants made with magnesium alloys will behave more like CFRP devices in MRI scans. Given its osseoconductive potential as a metal, implant alloys made with magnesium would combine the advantages to the two principal spacer materials currently used but without their limitations, at least in terms of MRI artifacting. (orig.)

  1. Cadmium immobilization by hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Smičiklas Ivana D.

    2003-01-01

    Full Text Available The contamination of air, soil and water by cadmium is a great environmental problem. If cadmium occurs in nature in ionic form, soluble in water, it easily enters into the food chain. Hydroxyapatite (HAP, Ca-o(POAe(OH2 is a sparingly soluble salt and an excellent matrix for the removal of heavy metals from solutions. Considerable research attention has been paid to the bond between Cc/2+ ions and synthetic hydroxyapatite of known composition. The sorption mechanism is complex. The dominant process is ion exchange, but surface adsorption, surface complexation and coprecipitation can also contribute to the overall mechanism. The sorption capacity depends on the characteristics of hydroxyapatite itself and on the experimental conditions. Under optimum conditions a maximum capacity of 0.8 mol Cd2+/mol HAP can be achieved. HAP is a potential sorbent for the remediation of contaminated water and soil, for industrial waste treatment, and it is also referenced as a material that can be used as a barrier around waste depositories.

  2. Preparation and characterization of silane-modified SiO2particles reinforced resin composites with fluorinated acrylate polymer.

    Science.gov (United States)

    Liu, Xue; Wang, Zengyao; Zhao, Chengji; Bu, Wenhuan; Na, Hui

    2018-01-10

    A series of fluorinated dental resin composites were prepared with two kinds of SiO 2 particles. Bis-GMA (bisphenol A-glycerolate dimethacrylate)/4-TF-PQEA (fluorinated acrylate monomer)/TEGDMA (triethylene glycol dimethacrylate) (40/30/30, wt/wt/wt) was introduced as resin matrix. SiO 2 nanopartices (30nm) and SiO 2 microparticles (0.3µm) were silanized with 3-methacryloxypropyl trimethoxysilane (γ-MPS) and used as fillers. After mixing the resin matrix with 0%, 10%, 20%, 30% SiO 2 nanopartices and 0%, 10%, 20%, 30%, 40%, 50% SiO 2 microparticles, respectively, the fluorinated resin composites were obtained. Properties including double bond conversion (DC), polymerization shrinkage (PS), water sorption (W p ), water solubility (W y ), mechanical properties and cytotoxicity were investigated in comparison with those of neat resin system. The results showed that, filler particles could improve the overall performance of resin composites, particularly in improving mechanical properties and reducing PS of composites along with the addition of filler loading. Compared to resin composites containing SiO 2 microparticles, SiO 2 nanoparticles resin composites had higher DC, higher mechanical properties, lower PS and lower W p under the same filler content. Especially, 50% SiO 2 microparticles reinforced resins exhibited the best flexural strength (104.04 ± 7.40MPa), flexural modulus (5.62 ± 0.16GPa), vickers microhardness (37.34 ± 1.13 HV), compressive strength (301.54 ± 5.66MPa) and the lowest polymerization (3.42 ± 0.22%). Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. [Fixed angle carbon fiber reinforced polymer composite plate for treatment of distal radius fractures : Pilot study on clinical applications].

    Science.gov (United States)

    Behrendt, P; Kruse, E; Klüter, T; Fitschen-Oestern, S; Weuster, M; Menzdorf, L; Finn, J; Varoga, D; Seekamp, A; Müller, M; Lippross, S

    2017-02-01

    The clinical implementation of a new carbon-fiber-reinforced polyetheretherketon (PEEK) plate for distal radius fractures might offer advantageous properties over the conventional metallic devices. This includes similar elastic modulus to cortical bone, radiolucency, low artifacts on MRI scans and the lack of metal allergies. The aim of this study was to evaluate the clinical results at 6-week and 12-month follow-up using either a new fixed angle (monoaxial) PEEK plate system or a fixed angle (polyaxial) titanium plate. We included 26 patients (mean age 59.3) with displaced fractures of the distal radius (all AO types). Radiological and functional outcomes were measured prospectively at a 6-week and 12 month follow-up. We documented no cases of hardware breakage or significant loss of the surgically achieved fracture reduction with the usage oft the new PEEK device. Operating time was 101.0 min using PEEK versus 109.3 min in titanium plates, recorded times were including preparation, draping, and postoperative processing (ns, p 0.156). At the 6-week follow up the PEEK plate showed a trend for better range of motion and functional results (DASH-score, Mayo-wrist score, VAS) with no statistical significance. Results of 12 month follow up with PEEK showed comparable results with corresponding studies examining titanium plate after this period. First experience with PEEK plate osteosynthesis demonstrate quick clinical implementation with good clinical outcome and the advantage of excellent postoperative radiological assessment. At early follow-up PEEK even showed a trend for improved functional results.

  4. GFRP reinforced concrete bridge decks.

    Science.gov (United States)

    2000-07-01

    This report investigates the application of glass fiber reinforced polymer (GFRP) rebars in concrete bridge decks as a potential replacement or supplement to conventional steel rebars. Tests were conducted to determine the material properties of the ...

  5. Mechanical Properties of Chitosan-Starch Composite Filled Hydroxyapatite Micro- and Nanopowders

    Directory of Open Access Journals (Sweden)

    Jafar Ai

    2011-01-01

    Full Text Available Hydroxyapatite is a biocompatible ceramic and reinforcing material for bone implantations. In this study, Starch-chitosan hydrogel was produced using the oxidation of starch solution and subsequently cross-linked with chitosan via reductive alkylation method (weight ratio (starch/chitosan: 0.38. The hydroxyapatite micropowders and nanopowders synthesized by sol-gel method (10, 20, 30, 40 %W were composited to hydrogels and were investigated by mechanical analysis. The results of SEM images and Zetasizer experiments for synthesized nanopowders showed an average size of 100 nm. The nanoparticles distributed as uniform in the chitosan-starch film. The tensile modulus increased for composites containing hydroxyapatite nano-(size particle: 100 nanometer powders than composites containing micro-(size particle: 100 micrometer powders. The swelling percentage decreased for samples containing hydroxyapatite nanopowder than the micropowders. These nanocomposites could be applied for hard-tissue engineering.

  6. Short and long term behaviour of externally bonded fibre reinforced polymer laminates with bio-based resins for flexural strengthening of concrete beams

    Science.gov (United States)

    McSwiggan, Ciaran

    The use of bio-based resins in composites for construction is emerging as a way to reduce of embodied energy produced by a structural system. In this study, two types of bio-based resins were explored: an epoxidized pine oil resin blend (EP) and a furfuryl alcohol resin (FA) derived from corn cobs and sugar cane. Nine large-scale reinforced concrete beams strengthened using externally bonded carbon and glass fibre reinforced bio-based polymer (CFRP and GFRP) sheets were tested. The EP resin resulted in a comparable bond strength to conventional epoxy (E) when used in wet layup, with a 7% higher strength for CFRP. The FA resin, on the other hand, resulted in a very weak bond, likely due to concrete alkalinity affecting curing. However, when FA resin was used to produce prefabricated cured CFRP plates which were then bonded to concrete using conventional epoxy paste, it showed an excellent bond strength. The beams achieved an increase in peak load ranging from 18-54% and a 9-46% increase in yielding load, depending on the number of FRP layers and type of fibres and resin. Additionally, 137 concrete prisms with a mid-span half-depth saw cut were used to test CFRP bond durability, and 195 CFRP coupons were used to examine tensile strength durability. Specimens were conditioned in a 3.5% saline solution at 23, 40 or 50°C, for up to 240 days. Reductions in bond strength did not exceed 15%. Bond failure of EP was adhesive with traces of cement paste on CFRP, whereas that of FA was cohesive with a thicker layer of concrete on CFRP, suggesting that the bond between FA and epoxy paste is excellent. EP tension coupons had similar strength and modulus to E resin, whereas FA coupons had a 9% lower strength and 14% higher modulus. After 240 days of exposure, maximum reductions in tensile strength were 8, 19 and 10% for EP, FA and E resins, respectively. Analysis of Variance (ANOVA) was also performed to assess the significance of the reductions observed. High degrees of

  7. Polypropylene Biocomposites with Boron Nitride and Nanohydroxyapatite Reinforcements

    Directory of Open Access Journals (Sweden)

    Kai Wang Chan

    2015-03-01

    Full Text Available In this study, we develop binary polypropylene (PP composites with hexagonal boron nitride (hBN nanoplatelets and ternary hybrids reinforced with hBN and nanohydroxyapatite (nHA. Filler hybridization is a sound approach to make novel nanocomposites with useful biological and mechanical properties. Tensile test, osteoblastic cell culture and dimethyl thiazolyl diphenyl tetrazolium (MTT assay were employed to investigate the mechanical performance, bioactivity and biocompatibility of binary PP/hBN and ternary PP/hBN-nHA composites. The purpose is to prepare biocomposite nanomaterials with good mechanical properties and biocompatibility for replacing conventional polymer composites reinforced with large hydroxyapatite microparticles at a high loading of 40 vol%. Tensile test reveals that the elastic modulus of PP composites increases, while tensile elongation decreases with increasing hBN content. Hybridization of hBN with nHA further enhances elastic modulus of PP. The cell culture and MTT assay show that osteoblastic cells attach and proliferate on binary PP/hBN and ternary PP/hBN-20%nHA nanocomposites.

  8. The life times of polymer composites in construction

    Science.gov (United States)

    Meier, Urs

    2016-05-01

    This paper discusses examples that prove the long-term reliability of Fiber Reinforced Polymers (FRP) under extreme loading conditions and outdoor weathering. Results of polymer/steel-composite anchorage systems, Glass Fiber Reinforced Polymer (GFRP) plates and shells, GFRP box girders, Carbon Fiber Reinforced Polymer (CFRP) post-tensioning tendons and CFRP stays are going to be presented.

  9. Nonlinear Progressive Damage Analysis of Notched or Bolted Fibre-Reinforced Polymer (FRP Laminates Based on a Three-Dimensional Strain Failure Criterion

    Directory of Open Access Journals (Sweden)

    Yue Liu

    2014-03-01

    Full Text Available Notching and bolting are commonly utilised in connecting fibre-reinforced polymer (FRP laminates. These mechanical methods are usually superior to other connections, particularly when joining thick composite laminates. Stress distributions, damage modes and ultimate strengths in notched or bolted FRP laminate designs are of particular interest to the industrial community. To predict the ultimate strengths and the failure processes of notched or bolted composite laminates, nonlinear progressive damage analyses (PDA based on the finite element method (FEM at the meso-scale level are performed in this paper. A three-dimensional strength criterion in terms of strains, which can distinguish different damage modes, was developed and adopted in the analysis model to detect damage initiation in the laminates. Different material degradation methods and the influence of cohesive layers were discussed and compared with results of verification experiments. The results showed that the analysis model that used the succinct strength criterion proposed in this paper could properly predict the damage initiation and the ultimate strengths of notched or bolted FRP laminates. The errors between the numerical results and experimental data were small. The material degradation method with continuum damage mechanics (CDM-based exponential damage factors using the damage index as the independent variable achieved greater accuracy and convergence than the method with CDM-based exponential damage factors using the square index as the independent variable or than the method with constant damage factors. Adding cohesive layers in the model had negligible influence on the final results, largely because the succinct analysis model proposed in this paper is sufficiently accurate in cases of small delamination.

  10. Carbon nanotubes reinforced composites for biomedical applications.

    Science.gov (United States)

    Wang, Wei; Zhu, Yuhe; Liao, Susan; Li, Jiajia

    2014-01-01

    This review paper reported carbon nanotubes reinforced composites for biomedical applications. Several studies have found enhancement in the mechanical properties of CNTs-based reinforced composites by the addition of CNTs. CNTs reinforced composites have been intensively investigated for many aspects of life, especially being made for biomedical applications. The review introduced fabrication of CNTs reinforced composites (CNTs reinforced metal matrix composites, CNTs reinforced polymer matrix composites, and CNTs reinforced ceramic matrix composites), their mechanical properties, cell experiments in vitro, and biocompatibility tests in vivo.

  11. Colloidal liquid crystal reinforced nanocomposites

    OpenAIRE

    Ozdilek, C.

    2006-01-01

    The main objective of this research is to investigate the use of colloidal Boehmite rods as reinforcement filler for polymer nanocomposites and to introduce them as an alternative to the well-known clay systems. Since Boehmite rods have been studied for many years as a model nematic system, the motivation was to explore some additional properties which could arise from their nematic behaviour in a polymer matrix. The Boehmite system was expected to retain the nematic behavior in the polymer m...

  12. Fiber reinforced polymer bridge decks.

    Science.gov (United States)

    2011-01-01

    The overarching goal of this study was to perform a comprehensive evaluation of various issues related to the strength and serviceability : of the FRP deck panels that are available in the industry. Specific objectives were to establish critical limi...

  13. Design of fibre reinforced PV concepts for building integrated applications

    NARCIS (Netherlands)

    Reinders, Angelina H.M.E.; de Wit, H.; de Boer, Andries; Ossenbrink Sinke, W.; Helm, P.

    2009-01-01

    Fibre reinforced polymers present an interesting encapsulation medium for PV-modules. Glass fibres can provide increased strength and stiffness to thin polymer layers overcoming the brittleness and limited deformability of glass-panes. Glass fibre reinforced polymers allows for transparency over a

  14. Al(OH)3 facilitated synthesis of water-soluble, magnetic, radiolabelled and fluorescent hydroxyapatite nanoparticles

    NARCIS (Netherlands)

    Cui, X.; Green, M.A.; Blower, P.J.; Zhou, D.; Yan, Y.; Zhang, W.; Djanashvili, K.; Mathe, D.; Veres, D.S.; Szigeti, K.

    2015-01-01

    Magnetic and fluorescent hydroxyapatite nanoparticles were synthesised using Al(OH)3-stabilised MnFe2O4 or Fe3O4 nanoparticles as precursors. They were readily and efficiently radiolabelled with 18F. Bisphosphonate polyethylene glycol polymers were utilised to endow the nanoparticles with excellent

  15. Al(OH)3 facilitated synthesis of water-soluble, magnetic, radiolabelled and fluorescent hydroxyapatite nanoparticles.

    Science.gov (United States)

    Cui, X; Green, M A; Blower, P J; Zhou, D; Yan, Y; Zhang, W; Djanashvili, K; Mathe, D; Veres, D S; Szigeti, K

    2015-06-07

    Magnetic and fluorescent hydroxyapatite nanoparticles were synthesised using Al(OH)3-stabilised MnFe2O4 or Fe3O4 nanoparticles as precursors. They were readily and efficiently radiolabelled with (18)F. Bisphosphonate polyethylene glycol polymers were utilised to endow the nanoparticles with excellent colloidal stability in water and to incorporate cyclam for high affinity labelling with (64)Cu.

  16. Definition of key sustainability performance indicators and multicriteria evaluation of recycling sector for carbon fiber reinforced polymers from the aerospace industry

    OpenAIRE

    Pillain, Baptiste

    2017-01-01

    The global consumption of carbon-fiber reinforced plastic (CFRP) is constantly growing since the last decade, leading to the need to create a recycling sector able to manage the amount of carbon fibers currently consumed and representing the amount of waste to be treated in the future. This thesis focus on the creation of a methodology for evaluating the sustainability potential for the implementation of a carbon fiber reinforced plastics recycling (CFRP) sector. CFRP coming from the aeronaut...

  17. In Vitro Degradation of PHBV Scaffolds and nHA/PHBV Composite Scaffolds Containing Hydroxyapatite Nanoparticles for Bone Tissue Engineering

    OpenAIRE

    Naznin Sultana; Tareef Hayat Khan

    2012-01-01

    This paper investigated the long-term in vitro degradation properties of scaffolds based on biodegradable polymers and osteoconductive bioceramic/polymer composite materials for the application of bone tissue engineering. The three-dimensional porous scaffolds were fabricated using emulsion-freezing/freeze-drying technique using poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) which is a natural biodegradable and biocompatible polymer. Nanosized hydroxyapatite (nHA) particles were successfully...

  18. Variability of hydroxyapatite preparations.

    Science.gov (United States)

    Young, R A; Holcomb, D W

    1982-01-01

    Hydroxyapatite synthesized by various "standard" ways exhibits marked differences with preparation method. Specimens were prepared with two precipitation methods, a reflux method, a hydrothermal method, a high-temperature (1000 degrees C) solid-state reaction method, and by conversion of chlorapatite at 1000 degrees C. They were compared in detail by use of several techniques, the major ones being x-ray diffraction including Rietveld structure refinements, quantitative i.r. analyses, and deuteration kinetics studies. At least some of the specimens differed with respect to each of the approximately 14 properties measured. The major lattice parameter differences could be largely accounted for by structurally incorporated H2O, CO2-3, and + O2- for 2(OH)-. Deuterizability was used as an indicator of ease of diffusion along the X-ion channels, a property that may be related to dissolution kinetics. The differently prepared specimens differed in deuterizability by at least two orders of magnitude. The high-temperature preparations, which were monoclinic, deuterated little at 110 degrees C, even in 1000 h. The precipitated and reflux specimens deuterated readily. There were general indications of correlation between ease of diffusion and features providing passing sites for the diffusing species, e.g., OH- disorder, vacancies, and distortions in the walls of the X-ion channels (mostly by CO3 for PO4), and possibly OH- vacancies. Correlation of structural H2O, present in the aqueous preparations, with ease of diffusion is still ambiguous.

  19. Antibacterial effects of silver-doped hydroxyapatite thin films sputter deposited on titanium

    Energy Technology Data Exchange (ETDEWEB)

    Trujillo, Nathan A. [Dept. of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523-1374 (United States); School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523-1376 (United States); Oldinski, Rachael A. [College of Engineering and Mathematical Science, University of Vermont, Burlington, VT 05405 (United States); Dept. of Bioengineering, University of Washington, Seattle, WA 98195-5061 (United States); Ma, Hongyan; Bryers, James D. [Dept. of Bioengineering, University of Washington, Seattle, WA 98195-5061 (United States); Williams, John D. [Dept. of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523-1374 (United States); Popat, Ketul C., E-mail: Ketul.Popat@colostate.edu [Dept. of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523-1374 (United States); School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523-1376 (United States)

    2012-12-01

    Since many orthopedic implants fail as a result of loosening, wear, and inflammation caused by repeated loading on the joints, coatings such as hydroxyapatite (HAp) on titanium with a unique topography have been shown to improve the interface between the implant and the natural tissue. Another serious problem with long-term or ideally permanent implants is infection. It is important to prevent initial bacterial colonization as existing colonies have the potential to become encased in an extracellular matrix polymer (biofilm) that is resistant to antibacterial agents. In this study, plasma-based ion implantation was used to examine the effects of pre-etching on plain titanium. Topographical changes to the titanium samples were examined and compared via scanning electron microscopy. Hydroxyapatite and silver-doped hydroxyapatite thin films were then sputter deposited on titanium substrates etched at - 700 eV. For silver-doped films, two concentrations of silver ({approx} 0.5 wt.% and {approx} 1.5 wt.%) were used. Silver concentrations in the film were determined using energy dispersive X-ray spectroscopy. Hydroxyapatite film thicknesses were determined by measuring the surface profile using contact profilometry. Staphylococcus epidermidis and Pseudomonas aeruginosa adhesion studies were performed on plain titanium, titanium coated with hydroxyapatite, titanium coated with {approx} 0.5 wt.% silver-doped hydroxyapatite, and titanium coated with {approx} 1.5 wt.% silver-doped hydroxyapatite. Results indicate that less bacteria adhered to surfaces containing hydroxyapatite and silver; further, as the hydroxyapatite films delaminated, silver ions were released which killed bacteria in suspension. - Highlights: Black-Right-Pointing-Pointer We have developed a combination of plasma-based ion implantation and ion beam sputter deposition technique. Black-Right-Pointing-Pointer Silver-doped hydroxyapatite thin films on titanium were developed. Black-Right-Pointing-Pointer The

  20. Structural transformation of synthetic hydroxyapatite under simulated in vivo conditions studied with ATR-FTIR spectroscopic imaging

    Science.gov (United States)

    Sroka-Bartnicka, Anna; Borkowski, Leszek; Ginalska, Grazyna; Ślósarczyk, Anna; Kazarian, Sergei G.

    2017-01-01

    Hydroxyapatite and carbonate-substituted hydroxyapatite are widely used in bone tissue engineering and regenerative medicine. Both apatite materials were embedded into recently developed ceramic/polymer composites, subjected to Simulated Body Fluid (SBF) for 30 days and characterized using ATR-FTIR spectroscopic imaging to assess their behaviour and structures. The specific aim was to detect the transition phases between both types of hydroxyapatite during the test and to analyze the surface modification caused by SBF. ATR-FTIR spectroscopic imaging was successfully applied to characterise changes in the hydroxyapatite lattice due to the elastic properties of the scaffolds. It was observed that SBF treatment caused a replacement of phosphates in the lattice of non-substituted hydroxyapatite by carbonate ions. A detailed study excluded the formation of pure A type carbonate apatite. In turn, CO32- content in synthetic carbonate-substituted hydroxyapatite decreased. The usefulness of ATR-FTIR spectroscopic imaging studies in the evaluation of elastic and porous β-glucan hydroxyapatite composites has been demonstrated.

  1. Evaluation of Hydroxyapatite-Forsterite Glass Composite Nanopowder Prepared via Sol-Gel Method

    Science.gov (United States)

    Mazrooei Sebdani, Maryam; Fathi, Mohammadhossein

    In spite of attractive bioactivity of bioactive ceramics i.e. hydroxyapatite and bioactive glasses, their poor mechanical properties have restricted their clinical applications. To overcome these limitations, an alternative approach suggested is preparation a composite including these bioactive ceramics with others. It is expected that a ceramic reinforcement with reduced grain size below 100 nm promotes theirs. The aim of this work was fabrication and characterization of hydroxyapatite-forsterite-bioglass composite nanopowder. Novel hydroxyapatite-forsterite-bioglass composite nanopowder was synthesized by incorporation of the forsterite and bioactive glass in hydroxyapatite matrix via a sol-gel process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and fourier transform infrared (FTIR) spectroscopy techniques were utilized in order to evaluate the phase composition, agglomerates size distribution, morphology and particle size and functional groups of synthesized. The effects of sintering temperature and time were also investigated. Results showed that the appropriate temperature for calcination was 600°C and the particle size of composite nanopowder was about 60-70nm. The decomposition of hydroxyapatite was increased with the increase of the sintering temperature and sintering time. Obtained results indicate that prepared composite nanopowder could be a good candidate for medical applications.

  2. Hydroxyapatite-alginate nanocomposite as drug delivery matrix for sustained release of ciprofloxacin.

    Science.gov (United States)

    Venkatasubbu, G Devanand; Ramasamy, S; Ramakrishnan, V; Kumar, J

    2011-12-01

    Hydroxyapatite is a bioceramic which has a wide range of medical application for bone diseases. To enhance its usage, we have prepared ciprofloxacin loaded nano hydroxyapatite (HA) composite with a natural polymer, alginate, using wet chemical method at low temperature. The prepared composites were analyzed by various physicochemical methods. The results show that the nano HA crystallites are well intact with the alginate macromolecules. For the composite system FT-IR and micro Raman results are reported in this paper. Studies on the drug loading and drug release have been done. The drug is pre-adsorbed onto the ceramic particle before the formation of composite. The thermal behavior of composite has been studied using thermo gravimetric analysis (TGA). This work, reports that the nanocomposite prepared under optimum condition could prolong the release of ciprofloxacin compared with the ciprofloxacin loaded hydroxyapatite.

  3. Biodegradable magnesium-hydroxyapatite metal matrix composites.

    Science.gov (United States)

    Witte, Frank; Feyerabend, Frank; Maier, Petra; Fischer, Jens; Störmer, Michael; Blawert, Carsten; Dietzel, Wolfgang; Hort, Norbert

    2007-04-01

    Recent studies indicate that there is a high demand to design magnesium alloys with adjustable corrosion rates and suitable mechanical properties. An approach to this challenge might be the application of metal matrix composite (MMC) based on magnesium alloys. In this study, a MMC made of magnesium alloy AZ91D as a matrix and hydroxyapatite (HA) particles as reinforcements have been investigated in vitro for mechanical, corrosive and cytocompatible properties. The mechanical properties of the MMC-HA were adjustable by the choice of HA particle size and distribution. Corrosion tests revealed that HA particles stabilised the corrosion rate and exhibited more uniform corrosion attack in artificial sea water and cell solutions. The phase identification showed that all samples contained hcp-Mg, Mg(17)Al(12), and HA before and after immersion. After immersion in artificial sea water CaCO3 was found on MMC-HA surfaces, while no formation of CaCO3 was found after immersion in cell solutions with and without proteins. Co-cultivation of MMC-HA with human bone derived cells (HBDC), cells of an osteoblasts lineage (MG-63) and cells of a macrophage lineage (RAW264.7) revealed that RAW264.7, MG-63 and HBDC adhere, proliferate and survive on the corroding surfaces of MMC-HA. In summary, biodegradable MMC-HA are cytocompatible biomaterials with adjustable mechanical and corrosive properties.

  4. Immobilisation of hydroxyapatite-collagen on polydopamine grafted stainless steel 316L: Coating adhesion and in vitro cells evaluation.

    Science.gov (United States)

    Tapsir, Zafirah; Jamaludin, Farah H; Pingguan-Murphy, Belinda; Saidin, Syafiqah

    2018-02-01

    The utilisation of hydroxyapatite and collagen as bioactive coating materials could enhance cells attachment, proliferation and osseointegration. However, most methods to form crystal hydroxyapatite coating do not allow the incorporation of polymer/organic compound due to production phase of high sintering temperature. In this study, a polydopamine film was used as an intermediate layer to immobilise hydroxyapatite-collagen without the introduction of high sintering temperature. The surface roughness, coating adhesion, bioactivity and osteoblast attachment on the hydroxyapatite-collagen coating were assessed as these properties remains unknown on the polydopamine grafted film. The coating was developed by grafting stainless steel 316L disks with a polydopamine film. Collagen type I fibres were then immobilised on the grafted film, followed by the biomineralisation of hydroxyapatite. The surface roughness and coating adhesion analyses were later performed by using AFM instrument. An Alamar Blue assay was used to determine the cytotoxicity of the coating, while an alkaline phosphatase activity test was conducted to evaluate the osteogenic differentiation of human fetal osteoblasts on the coating. Finally, the morphology of cells attachment on the coating was visualised under FESEM. The highest RMS roughness and coating adhesion were observed on the hydroxyapatite-collagen coating (hydroxyapatite-coll-dopa). The hydroxyapatite-coll-dopa coating was non-toxic to the osteoblast cells with greater cells proliferation, greater level of alkaline phosphate production and more cells attachment. These results indicate that the immobilisation of hydroxyapatite and collagen using an intermediate polydopamine is identical to enhance coating adhesion, osteoblast cells attachment, proliferation and differentiation, and thus could be implemented as a coating material on orthopaedic and dental implants.

  5. Can Plant-Based Natural Flax Replace Basalt and E-Glass for Fiber-Reinforced Polymer Tubular Energy Absorbers? A Comparative Study on Quasi-Static Axial Crushing

    Directory of Open Access Journals (Sweden)

    Libo Yan

    2017-12-01

    Full Text Available Using plant-based natural fibers to substitute glass fibers as reinforcement of composite materials is of particular interest due to their economic, technical, and environmental significance. One potential application of plant-based natural fiber reinforced polymer (FRP composites is in automotive engineering as crushable energy absorbers. Current study experimentally investigated and compared the energy absorption efficiency of plant-based natural flax, mineral-based basalt, and glass FRP (GFRP composite tubular energy absorbers subjected to quasi-static axial crushing. The effects of number of flax fabric layer, the use of foam filler and the type of fiber materials on the crashworthiness characteristics, and energy absorption capacities were discussed. In addition, the failure mechanisms of the hollow and foam-filled flax, basalt, and GFRP tubes in quasi-static axial crushing were analyzed and compared. The test results showed that the energy absorption capabilities of both hollow and foam-filled energy absorbers made of flax were superior to the corresponding energy absorbers made of basalt and were close to energy absorbers made of glass. This study, therefore, indicated that flax fiber has the great potential to be suitable replacement of basalt and glass fibers for crushable energy absorber application.

  6. OPTIMISATION OF THICKNESS OF FIBRE REINFORCED ...

    African Journals Online (AJOL)

    The use of Fiber Reinforced Polymer (FRP) is becoming a widely accepted solution for repairing and strengthening of deteriorated reinforced concrete members, to restore their load carrying capacities. One of the major concerns in the use of FRP is its cost. This therefore calls for the use of efficient and cost effective design ...

  7. Organic Polymers Modified with Inorganic Polyhedra

    National Research Council Canada - National Science Library

    Haddad, Timothy

    2002-01-01

    ...) macromers into organic polymers. These hybrid inorganic/organic thermoplastics based on styrenes, acrylics, imides, norbornenes or siloxanes, are reinforced by covalently linking monodisperse inorganic POSS clusters to the polymer backbone...

  8. Nanofiber generation of hydroxyapatite and fluor-hydroxyapatite bioceramics.

    Science.gov (United States)

    Kim, Hae-Won; Kim, Hyoun-Ee

    2006-05-01

    In this study, we produced hydroxyapatite (HA) and fluor-hydroxyapatite (FHA) bioceramics as a novel geometrical form, the nanoscale fiber, for the biomedical applications. Based on the sol-gel precursors of the apatites, an electrospinning technique was introduced to generate nanoscale fibers. The diameter of the fibers was exploited in the range of a few micrometers to hundreds of nanometers (1.55 microm-240 nm) by means of adjusting the concentration of the sols. Through the fluoridation of apatite, the solubility of the fiber was tailored and the fluorine ions were well released from the FHA. The HA and FHA nanofibers produced in this study are considered to find potential applications in the biomaterials and tissue engineering fields. (c) 2005 Wiley Periodicals, Inc.

  9. Colloidal liquid crystal reinforced nanocomposites

    NARCIS (Netherlands)

    Ozdilek, C.

    2006-01-01

    The main objective of this research is to investigate the use of colloidal Boehmite rods as reinforcement filler for polymer nanocomposites and to introduce them as an alternative to the well-known clay systems. Since Boehmite rods have been studied for many years as a model nematic system, the

  10. Evaluation of the effect of home bleaching agents on surface microhardness of different glass-ionomer cements containing hydroxyapatite.

    Science.gov (United States)

    Sharafeddin, Farahnaz; Kowkabi, Mahsa; Shoale, Soodabe

    2017-09-01

    Home bleaching agents may exert some negative effects on surface hardness of restorative materials such as glass-ionomer cements (GICs). Since some studies have shown that some components such as hydroxyapatite (HA), as a bioactive glass, can improve the mechanical properties of dental materials, the effect of bleaching agents on surface hardness of GICs containing hydroxyapatite is questionable. This study was designed to evaluate the effect of home bleaching agents on the surface hardness of two different commercially available GICs containing hydroxyapatite. 80 disk-shaped specimens were made from two different GICs, including resin modified glass-ionomer and Zirconomer. Each material was divided into four groups (n=10): 1. control, 2. 20 %wt. hydroxyapatite-containing, 3. bleached and 4. bleached 20 %wt. hydroxyapatite-containing. Group 1 and 2 specimens were stored in distilled water for 2 weeks while group 3 and 4 specimens were treated with 15% carbamide peroxide in that period. Surface hardness was tested with Vickers surface hardness tester. Data were analyzed with 3-way ANOVA and mean comparison done by post hoc Tukey tests (pGlass-ionomer cement, surface hardness, Zirconia-reinforced glass ionomer, hydroxyapatite.

  11. Sulfobetaine as a zwitterionic mediator for 3D hydroxyapatite mineralization

    Science.gov (United States)

    Liu, Pingsheng; Song, Jie

    2013-01-01

    Both positively and negatively charged residues play pivotal roles in recruiting precursor ions or ion clusters, and lowering interfacial energy in natural biomineralization process. Synergistic utilization of opposite charges, however, has rarely been implemented in the design of cytocompatible synthetic scaffolds promoting hydroxyapatite (HA)-mineralization and osteointegration. We report the use of cytocompatible zwitterionic sulfobetaine ligands to enable 3-dimensional in vitro mineralization of HA across covalently crosslinked hydrogels. The overall charge-neutral zwitterionic hydrogel effectively recruited oppositely charged precursor ions while overcame excessive swelling exhibited by anionic and cationic hydrogels under physiological conditions, resulting in denser and structurally well-integrated mineralized composites. Further controls over the size, content, and spatial distribution of the mineral domains within the zwitterionic hydrogel are accomplished by facile adjustments of hydrogel crosslinking densities and the supersaturation rate governing heterogeneous mineral nucleation and growth. These findings should inspire many creative uses of zwitterionic polymers and polymer coatings for skeletal tissue repair and regeneration. PMID:23332320

  12. Biopolymers for Medical Applications: Polyglycerol Sebacate (PGS) doped Hydroxyapatite (HA)

    Science.gov (United States)

    Teruel, Maria; Kuthirummal, Narayanan; Levi, Nicole; Wake College Team

    2011-04-01

    In the investigation to engineer the ideal scaffolding device for cleft palate repair, polyglycerol sebacate (PGS) doped with hydroxyapatite (HA) were chosen for their elastomeric and biodegradable properties, as well as their cost-effective synthesis. Hydroxyapatite was integrated into the PGS to form a composite with high porosity and improved mechanical properties yielding a good substrate for cell attachment during the repair process. FT-IR scans were performed to characterize the composite polymer. Differential Scanning Calorimetry (DSC) was utilized to identify an acceptable glass transition temperature (Tg), between -18 and - 21°C. At this Tg, it was determined that the material was sufficiently polymerized to a point where it was durable yet pliable enough to use for cleft palate devices. In the synthesis of PGS 3% and 5% HA, a Tg of - 20.10°C and - 21.72°C, respectively, was achieved and further analytical tests were then performed on the polymers. Methods of analysis included X-Ray Diffraction and Tensile Strength Testing. Acknowledgements to the Research Department of Plastic and Reconstructive Surgery, Wake Forest University and College of Charleston.

  13. 3D silicon doped hydroxyapatite scaffolds decorated with Elastin-like Recombinamers for bone regenerative medicine.

    Science.gov (United States)

    Vila, Mercedes; García, Ana; Girotti, Alessandra; Alonso, Matilde; Rodríguez-Cabello, Jose Carlos; González-Vázquez, Arlyng; Planell, Josep A; Engel, Elisabeth; Buján, Julia; García-Honduvilla, Natalio; Vallet-Regí, María

    2016-11-01

    The current study reports on the manufacturing by rapid prototyping technique of three-dimensional (3D) scaffolds based on silicon substituted hydroxyapatite with Elastin-like Recombinamers (ELRs) functionalized surfaces. Silicon doped hydroxyapatite (Si-HA), with Ca10(PO4)5.7(SiO4)0.3(OH)1.7h0.3 nominal formula, was surface functionalized with two different types of polymers designed by genetic engineering: ELR-RGD that contain cell attachment specific sequences and ELR-SNA15/RGD with both hydroxyapatite and cells domains that interact with the inorganic phase and with the cells, respectively. These hybrid materials were subjected to in vitro assays in order to clarify if the ELRs coating improved the well-known biocompatible and bone regeneration properties of calcium phosphates materials. The in vitro tests showed that there was a total and homogeneous colonization of the 3D scaffolds by Bone marrow Mesenchymal Stromal Cells (BMSCs). In addition, the BMSCs were viable and able to proliferate and differentiate into osteoblasts. Bone tissue engineering is an area of increasing interest because its main applications are directly related to the rising life expectancy of the population, which promotes higher rates of several bone pathologies, so innovative strategies are needed for bone tissue regeneration therapies. Here we use the rapid prototyping technology to allow moulding ceramic 3D scaffolds and we use different bio-polymers for the functionalization of their surfaces in order to enhance the biological response. Combining the ceramic material (silicon doped hydroxyapatite, Si-HA) and the Elastin like Recombinamers (ELRs) polymers with the presence of the integrin-mediate adhesion domain alone or in combination with SNA15 peptide that possess high affinity for hydroxyapatite, provided an improved Bone marrow Mesenchymal Stromal Cells (BMSCs) differentiation into osteoblastic linkage. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights

  14. Cementless Hydroxyapatite Coated Hip Prostheses

    Science.gov (United States)

    Herrera, Antonio; Mateo, Jesús; Gil-Albarova, Jorge; Lobo-Escolar, Antonio; Ibarz, Elena; Gabarre, Sergio; Más, Yolanda

    2015-01-01

    More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality. PMID:25802848

  15. Cementless Hydroxyapatite Coated Hip Prostheses

    Directory of Open Access Journals (Sweden)

    Antonio Herrera

    2015-01-01

    Full Text Available More than twenty years ago, hydroxyapatite (HA, calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality.

  16. One- and three-dimensional growth of hydroxyapatite nanowires during sol-gel-hydrothermal synthesis.

    Science.gov (United States)

    Costa, Daniel O; Dixon, S Jeffrey; Rizkalla, Amin S

    2012-03-01

    Nanoscale hydroxyapatite (HA) is an optimal candidate biomaterial for bone tissue engineering because of its bioactive and osteoconductive properties. In this study, micro- and nanoscale HA particles with rod- and wirelike morphology were synthesized by a novel sol-gel-hydrothermal process. Sol-gel chemistry was used to produce a dry gel containing amorphous calcium phosphate (ACP), which was used as a precursor material in a hydrothermal process. The sol-gel-hydrothermal products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) to determine particle morphology, crystal structure, and the presence of chemical functional groups. A pure HA crystal was synthesized, which underwent both one- and three-dimensional growth, resulting in tunable microrod and nanorod, and wire morphologies. The effects of solution pH and reaction time on particle diameter and length were assessed. Particle diameter ranged from 25 to 800 nm and decreased with an increase in solution pH, whereas both particle length and diameter increased as the hydrothermal process was prolonged. Nanowire HA powders (10-50 wt %) were mixed with poly(ε-caprolactone) (PCL) to produce PCL/HA composites. Fracture surfaces of PCL/HA composites showed a well-dispersed and homogeneous distribution of HA nanowires within the PCL matrix. Mechanical testing revealed a significant (p < 0.05) increase in the Young's and compressive moduli of PCL/HA composites compared to PCL alone, with 50 wt % HA producing a 3-fold increase in Young's modulus from 193 to 665 MPa and 2-fold increase in compressive modulus from 230 to 487 MPa. These HA nanowires can be used to reinforce polymer composites and are excellent biomaterials for tissue engineering of bone. © 2012 American Chemical Society

  17. Shear Behavior of Concrete Beams Reinforced with GFRP Shear Reinforcement

    Directory of Open Access Journals (Sweden)

    Heecheul Kim

    2015-01-01

    Full Text Available This paper presents the shear capacities of concrete beams reinforced with glass fiber reinforced polymer (GFRP plates as shear reinforcement. To examine the shear performance, we manufactured and tested a total of eight specimens. Test variables included the GFRP strip-width-to-spacing ratio and type of opening array. The specimen with a GFRP plate with a 3×2 opening array showed the highest shear strength. From the test results, the shear strength increased as the strip-width-to-strip-spacing ratio increased. Also, we used the experimental results to evaluate whether the shear strength equations of ACI 318-14 and ACI 440.1R can be applied to the design of GFRP shear reinforcement. In the results, the ACI 440 equation underestimated the experimental results more than that of ACI 318.

  18. Flexural Reinforcement of Autoclaved Aerated Concrete (AAC) with ...

    African Journals Online (AJOL)

    The FRP composite material was made of carbon reinforcing fabrics embedded in an epoxy resin matrix. The carbon fiber reinforced polymer (CFRP) reinforcement was applied on the top and bottom faces of the AAC panel and several innovative processing techniques were used including hand lay up as well as VARTM ...

  19. Graphene reinforced nanocomposites: 3D simulation of damage and fracture

    DEFF Research Database (Denmark)

    Dai, Gaoming; Mishnaevsky, Leon

    2014-01-01

    sheets of graphene demonstrate much lower Young modulus and strength as compared with the composites with the aligned graphene sheet reinforcement. It was further concluded that the structural imperfections of graphene reinforcement (like crumpling shape or random misalignment) have considerable effect......3D computational model of graphene reinforced polymer composites is developed and applied to the analysis of damage and fracture mechanisms in the composites. The graphene/polymer interface properties are determined using the inverse modeling approach. The effect of composite structure...

  20. Silica reinforced triblock copolymer gels

    DEFF Research Database (Denmark)

    Theunissen, E.; Overbergh, N.; Reynaers, H.

    2004-01-01

    The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has been investigated. Different types of chemically modified silica have been compared in order...... to evaluate the influence of the compatibility between gel and filler. Time-resolved SANS and small-angle X-ray scattering (SAXS) shows that the presence of silica particles affects the ordering of the polystyrene domains during gelsetting. The scattering pattern of silica-reinforced gels reveals strong...... scattering at very low q, but no structure and formfactor information. However, on heating above the viscoelastic to plastic transition, the 'typical' scattering pattern of the copolymer gel builds-up. All reinforced gels are strengthened by the addition of the reinforcing agent. The transitions from...

  1. Electrospun Nanocomposite Materials, A Novel Synergy of Polyurethane and Bovine Derived Hydroxyapatite

    Science.gov (United States)

    Bozkurt, Y.; Sahin, A.; Sunulu, A.; Aydogdu, M. O.; Altun, E.; Oktar, F. N.; Ekren, N.; Gunduz, O.

    2017-04-01

    Polyurethane (PU) is a synthetic polymer that is used for construction of scaffold in tissue engineering applications in order to obtain desirable mechanical, physical and chemical properties like elasticity and durability. Bovine derived hydroxyapatite (BHAp) is a ceramic based natural polymer that is used as the most preferred implant material in orthopedics and dentistry due to their chemically and biologically similarity to the mineral phase found in the human bone structure. PU and bovine derived hydroxyapatite (BHAp) solutions with different concentrations were prepared with dissolving polyurethane and BHAp in Dimethylformamide (DMF) and Tetrahydrofuran (THF) solutions. Blended PU-BHAp solutions in different concentrations were used for electrospinning technique to create nanofiber scaffolds and new biocomposite material together. SEM, FTIR and physical analysis such as viscosity, electrical conductivity, density measurement and tensile strength measurement tests were carried out after production process.

  2. A new injectable biphasic hydrogel based on partially hydrolyzed polyacrylamide and nano hydroxyapatite, crosslinked with chromium acetate, as scaffold for cartilage regeneration

    Science.gov (United States)

    Koushki, N.; Tavassoli, H.; Katbab, A. A.; Katbab, P.; Bonakdar, S.

    2015-05-01

    Polymer scaffolds are applied in the field of tissue engineering as three dimensional structures to organize cells and present stimuli to direct generation of a desired damaged tissue. In situ gelling scaffolds have attracted great attentions, as they are structurally similar to the extra cellular matrix (ECM). In the present work, attempts have been made to design and fabricate a new injectable and crosslinkable biphasic hydrogel based on partially hydrolyzed polyacrylamide (HPAM), chromium acetate as crosslink agent and nanocrystalline hydroxyapatite (nHAp) as reinforcing and bioactive agent for repair and regeneration of damaged cartilage. The distinct characteristic of HPAM is the presence of carboxylate anion groups on its backbone which allows to engineer the structure of the hydrogel for the desired bioactivity with appropriate cells differentiation towards both soft and hard (bone) tissues. The synthesized hydrogel exhibited bifunctional behavior which was derived by its biphasic structure in which one phase was loaded with nano hydroxyapatite to provide integration capability by subchondral bones and fix the hydrogel at cartilage defect without a need for suturing. The other phase differentiates the rabbit adipogenic mesenchymal stem cells (MSCs) towards soft tissue. Rheomechanical spectrometry (RMS) was employed to study the kinetic of the gelation including induction time and rate, as well as to measure the ultimate elastic modulus of the optimum crosslinked hydrogel. Surface tension measurement was also performed to tailor the surface characteristics of the gels. In vitro culturing of the cells inside the crosslinked hydrogel revealed high viability and high differentiation of the encapsulated rabbit stem cells, providing that the chromium acetate level was kept below 0.2 wt%. Based on the obtained results, the designed and fabricated biphasic hydrogel exhibited high potential as carrier for the stem cells for cartilage tissue engineering application

  3. Synthesis of nanocrystalline fluorinated hydroxyapatite by ...

    Indian Academy of Sciences (India)

    Synthetic hydroxyapatite, (Ca10(PO4)6(OH)2, HA), is an important material used for orthopedic and dental implant applications. The biological hydroxyapatite in the human bone and tooth is of nanosize and differs in composition from the stoichiometric HA by the presence of other ions such as carbonate, magnesium, ...

  4. Molecular mechanics of tropocollagen-hydroxyapatite biomaterials

    Science.gov (United States)

    Dubey, Devendra Kumar

    Hard biomaterials such as bone, dentin, and nacre show remarkable mechanical performance and serve as inspiration for development of next generation of composite materials with high strength and toughness. Such materials have primarily an organic phase (e.g. tropocollagen (TC) or chitin) and a mineral phase (e.g. hydroxyapatite (HAP) or aragonite) arranged in a staggered arrangement at nanoscopic length scales. Interfacial interactions between the organic phases and the mineral phases and structural effects arising due to the staggered and hierarchical arrangements are identified to be the two most important determinants for high mechanical performance of such biomaterials. Effects of these determinants in such biomaterials are further intertwined with factors such as loading configuration, chemical environment, mineral crystal shape, and residue sequences in polymer chains. Atomistic modeling is a desired approach to investigate such sub nanoscale issues as experimental techniques for investigations at such small scale are still in nascent stage. For this purpose, explicit three dimensional (3D) molecular dynamics (MD) and ab initio MD simulations of quasi-static mechanical deformations of idealized Tropocollagen-Hydroxyapatite (TC-HAP) biomaterials with distinct interfacial arrangements and different loading configurations are performed. Focus is on developing insights into the molecular level mechanics of TC-HAP biomaterials at fundamental lengthscale with emphasis on interface phenomenon. Idealized TC-HAP atomistic models are analyzed for their mechanical strength and fracture failure behavior from the viewpoint of interfacial interactions between TC and HAP and associated molecular mechanisms. In particular, study focuses on developing an understanding of factors such as role of interfacial structural arrangement, hierarchical structure design, influence of water, effect of changes in HAP crystal shape, and mutations in TC molecule on the mechanical strength

  5. Introducing the fluorine doped natural hydroxyapatite-titania nanobiocomposite ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Karamian, Ebrahim [Advanced Materials Research Center, Faculty of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of); Abdellahi, Majid, E-mail: M.Abdellahi@Pa.iut.ac.ir [Advanced Materials Research Center, Faculty of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of); Khandan, Amirsalar [Young Researchers and Elite Club, Khomeinishahr Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Abdellah, Sana [Advanced Materials Research Center, Faculty of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of)

    2016-09-15

    In the present research, natural hydroxyapatite (NHA) was synthesized from bovine bones and then fluorine was doped into the NHA matrix to produce fluorine doped NHA (FNHA; natural fluor-hydroxyapatite) in optimum conditions. At the end an FNHA-TiO{sub 2} nanobiocomposite ceramic with excellent biocompatibility and good chemical stability was synthesized through a mechanochemical route and a subsequent two step sintering (TSS) process. Thermal gravimetric analysis (TGA), Differential scanning calorimetry (DSC), X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), inductive coupled plasma (ICP), and energy-dispersive X-ray spectroscopy (EDX) were used as the means for gathering and analysis of the results. According to the obtained results, TiO{sub 2} can prevent early decomposition of FNHA by the formation of the CaTiO{sub 3} phases and hence strengthen the interactions between the apatite particles which results in the increase of the mechanical properties. Besides, TiO{sub 2} provides more Si−OH nucleation sites for the formation of the apatite layers and hence more bioactivity. - Highlights: • This work begins with preparing natural hydroxyapatite from bovine bones via a simple method. • With increasing the TiO{sub 2} content reinforced in FNHA matrix, the compaction increases. • TiO{sub 2} can prevent early decomposition of FNHA by the formation of CaTiO{sub 3} phase. • TiO{sub 2} can strengthen the interactions between the apatite particles and increase of compaction. • With increasing TiO{sub 2} content, the Si−OH nucleation sites increases lead to more bioactivity.

  6. Study on the Effect of Surface Energy of Polypropylene/Polyamide12 polymer Hybrid Matrix Reinforced with Virgin and Recycled Carbon Fiber

    Science.gov (United States)

    Sena Maia, Bruno

    The presented work is focused on characterization of thermal treated recycled and virgin carbon fibers. Their thermal performances, chemical surface composition and its influence on interfacial adhesion phenomena on PP/PA12 hybrid matrix were compared using TGA, FTIR and XPS analysis. Additionally, differences between hybrid matrix structural performances of PP/PA12 using both surface modifiers PMPPIC and MAPP were investigated. Final mechanical properties improvements between 8% up to 17% were reached by addition of PMPPIC in PP/PA12 hybrid matrix. For PP/PA12 matrix reinforcement using virgin and recycled carbon fibers, impact energy was improved up to 98% compared with MAPP modified matrix leading to a novel composite with good energy absorption. Finally, wettability studies and surface free energy analysis of all materials studied support the effect of the addition of PMPPIC, MAPP and carbon fibers in final composite surface thermodynamics bringing important data correlation between interfacial adhesion mechanisms and final composite performance.

  7. Effect of anodic surface treatment on PAN-based carbon fiber and its relationship to the fracture toughness of the carbon fiber-reinforced polymer composites

    DEFF Research Database (Denmark)

    Sarraf, Hamid; Skarpova, Ludmila

    2008-01-01

    The effect of anodic surface treatment on the polyacrylonitrile (PAN)-based carbon fibers surface properties and the mechanical behavior of the resulting carbon fiber-polymer composites has been studied in terms of the contact angle measurements of fibers and the fracture toughness of composites....... Results from contact angle measurements revealed that the angle of electrolyte solution largely decreases with increasing current densities of treatments up to 0.4-0.5 A m(-2). The results obtained from the evolution of K-IC with flexure of the composites as a function of electric current density shown...... that the K-IC of the composite continually increases with increased current densities of the treatments up to 0.5 A m(-2), and a maximum strength value is found about 294 MPa cm(1/2) at the anodic treatment of 0.5 A m(-2). It can be concluded that the anodic surface treatment is largely influenced...

  8. Hydroxyapatite-TiO2-SiO2-Coated 316L Stainless Steel for Biomedical Application

    Science.gov (United States)

    Sidane, Djahida; Khireddine, Hafit; Bir, Fatima; Yala, Sabeha; Montagne, Alex; Chicot, Didier

    2017-07-01

    This study investigated the effectiveness of titania (TiO2) as a reinforcing phase in the hydroxyapatite (HAP) coating and silica (SiO2) single layer as a bond coat between the TiO2-reinforced hydroxyapatite (TiO2/HAP) top layer and 316L stainless steel (316L SS) substrate on the corrosion resistance and mechanical properties of the underlying 316L SS metallic implant. Single layer of SiO2 film was first deposited on 316L SS substrate and studied separately. Water contact angle measurements, X-ray photoelectron spectroscopy, and Fourier transform infrared spectrophotometer analysis were used to evaluate the hydroxyl group reactivity at the SiO2 outer surface. The microstructural and morphological results showed that the reinforcement of HAP coating with TiO2 and SiO2 reduced the crystallite size and the roughness surface. Indeed, the deposition of 50 vol pct TiO2-reinforced hydroxyapatite layer enhanced the hardness and the elastic modulus of the HAP coating, and the introduction of SiO2 inner layer on the surface of the 316L SS allowed the improvement of the bonding strength and the corrosion resistance as confirmed by scratch studies, nanoindentation, and cyclic voltammetry tests.

  9. Ostrich eggshell as calcium source for the synthesis of hydroxyapatite and hydroxyapatite partially substituted with zinc

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, J.R.M.; Louro, L.H.L.; Costa, A.M.; Silva, M.H. Prado da [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Campos, J.B. de, E-mail: josericardo@r-crio.com, E-mail: louro@ime.eb.br, E-mail: andrea@r-crio.com, E-mail: brantjose@gmail.com, E-mail: marceloprado@ime.eb.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil)

    2016-10-15

    In the present study, hydroxyapatite and Zn-substituted hydroxyapatite powders were synthesized using ostrich eggshell as a calcium source. The samples were analyzed by scanning electron microscopy with field emission gun, and X-ray diffraction (XRD) to identify the present phases, and X-ray fluorescence spectroscopy for quantitative chemical analysis of the synthesized and heat treated powders. The Fourier transform infrared spectroscopy technique was used before and after heat treatments at 700, 900 and 1100 °C in order to identify the functional groups present, as an additional technique to the XRD analysis. The results presented in this study represent a promising method for synthesis of hydroxyapatite and hydroxyapatite partially substituted with zinc, since the results showed no undesirable phases or impurities in the produced powders. It was observed that Zn-substituted hydroxyapatite showed higher thermal stability, when compared to pure hydroxyapatite. (author)

  10. a comparison of bond perform with reinforcements from son of bond ...

    African Journals Online (AJOL)

    User

    ame size reinforcement, whilst with 25 steel reinforcement, the difference. 30% indicating the influence of ize and concrete quality on the bond susceptibility of reinforcement to attendant weakening effect on bond to loss of adhesion, has made elop different methods of protecting with steel fibre reinforced polymer.

  11. Caracterización de bentonitas y zeolitas sin tratamiento como refuerzo en materiales compuestos de matriz polimérica//Characterization of untreated zeolites and bentonites as reinforcement in polymer matrix composites

    Directory of Open Access Journals (Sweden)

    Francisco Jesús Mondelo‐García

    2014-01-01

    Full Text Available Las bentonitas con microestructuras compuestas de placas silicio aluminosas. Se logró el objetivo de caracterizar las bentonitas sódicas de Wyoming, USA, Patagonia de Argentina, nordeste de Brasil, así como las bentonitas policatiónicas de Brasil, la cálcica activada con sodio y zeolita de Cuba no organofilizadas para emplearlas como refuerzo en materiales compuestos de matriz polimérica. Estosmateriales se evaluaron usando técnicas físico-químicas como fluorescencia de rayos X, difracción de rayos X, microscopia electrónica de barrido, humedad, capacidad de intercambio catiónico, absorción e hinchabilidad en diluyente acuoso. Los resultados confirmaron rangos variables de intercambio catiónico,hinchamiento y absorciòn en agua entre las bentonitas analizadas, debido a su naturaleza química estructural en hidratación, logrando mayores valores las sódicas, luego la cálcica activada y con menor valor las policatiónicas, pero permiten usarlas como carga en polímeros.Palabras claves: bentonita, zeolita, matriz polimérica, organofilizada, materiales compuestos._____________________________________________________________________________AbstractBentonites with aluminous silicon microstructure composed of plates. The work accomplished to characterize the sodium bentonites in Wyoming USA, Patagonia Argentina, Northeast Brazil and the Brazilian polycationic bentonites, calcium-activated sodium zeolite from Cuba without organic modificationnot organophilized to employ as reinforcing in composite materials of polymer matrix. These materials were evaluated for physical and chemical assay techniques such as X-ray fluorescence, X-ray diffraction, scanning electron microscopy, moisture, cation exchange capacity, absorption and swelling aqueousdiluent. The results confirmed variables ranges of cationic exchange, swelling and water absorption from the bentonites tested, due to its chemical-structural hydration, achieving higher values nature

  12. Substituted Hydroxyapatites with Antibacterial Properties

    Directory of Open Access Journals (Sweden)

    Joanna Kolmas

    2014-01-01

    Full Text Available Reconstructive surgery is presently struggling with the problem of infections located within implantation biomaterials. Of course, the best antibacterial protection is antibiotic therapy. However, oral antibiotic therapy is sometimes ineffective, while administering an antibiotic at the location of infection is often associated with an unfavourable ratio of dosage efficiency and toxic effect. Thus, the present study aims to find a new factor which may improve antibacterial activity while also presenting low toxicity to the human cells. Such factors are usually implemented along with the implant itself and may be an integral part of it. Many recent studies have focused on inorganic factors, such as metal nanoparticles, salts, and metal oxides. The advantages of inorganic factors include the ease with which they can be combined with ceramic and polymeric biomaterials. The following review focuses on hydroxyapatites substituted with ions with antibacterial properties. It considers materials that have already been applied in regenerative medicine (e.g., hydroxyapatites with silver ions and those that are only at the preliminary stage of research and which could potentially be used in implantology or dentistry. We present methods for the synthesis of modified apatites and the antibacterial mechanisms of various ions as well as their antibacterial efficiency.

  13. Development of the experimental procedure to examine the response of carbon fiber-reinforced polymer composites subjected to a high-intensity pulsed electric field and low-velocity impact.

    Science.gov (United States)

    Hart, Robert J; Zhupanska, Olesya I

    2016-01-01

    A new fully automated experimental setup has been developed to study the response of carbon fiber reinforced polymer (CFRP) composites subjected to a high-intensity pulsed electric field and low-velocity impact. The experimental setup allows for real-time measurements of the pulsed electric current, voltage, impact load, and displacements on the CFRP composite specimens. The setup includes a new custom-built current pulse generator that utilizes a bank of capacitor modules capable of producing a 20 ms current pulse with an amplitude of up to 2500 A. The setup enabled application of the pulsed current and impact load and successfully achieved coordination between the peak of the current pulse and the peak of the impact load. A series of electrical, impact, and coordinated electrical-impact characterization tests were performed on 32-ply IM7/977-3 unidirectional CFRP composites to assess their ability to withstand application of a pulsed electric current and determine the effects of the pulsed current on the impact response. Experimental results revealed that the electrical resistance of CFRP composites decreased with an increase in the electric current magnitude. It was also found that the electrified CFRP specimens withstood higher average impact loads compared to the non-electrified specimens.

  14. Effect of the Volume Fraction of Jute Fiber on the Interlaminar Shear Stress and Tensile Behavior Characteristics of Hybrid Glass/Jute Fiber Reinforced Polymer Composite Bar for Concrete Structures

    Directory of Open Access Journals (Sweden)

    Chan-Gi Park

    2016-01-01

    Full Text Available Hybrid glass/jute fiber reinforced polymer (HGJFRP composite bars were manufactured for concrete structures, and their interlaminar shear stress and tensile performance were evaluated. HGJFRP composite bars were manufactured using a combination of pultrusion and braiding processes. Jute fiber was surface-treated with a silane coupling agent. The mixing ratio of the fiber to the vinyl ester used in the HGJFRP composite bars was 7 : 3. Jute fiber was used to replace glass fiber in proportions of 0, 30, 50, 70, and 100%. The interlaminar shear stress decreased as the proportion of jute fiber increased. Fractures appeared due to delamination between the surface-treated component and the main part of the HGJFRP composite bar. Tensile load-strain curves with 50% jute fiber exhibited linear behavior. With a jute fiber volume fraction of 70%, some plastic deformation occurred. A jute fiber mixing ratio of 100% resulted in a display of linear elastic brittle behavior from the fiber; however, when the surface of the fiber was coated with poly(vinyl acetate, following failure, the jute fiber exhibited partial load resistance. The tensile strength decreased as the jute fiber content increased; however, the tensile strength did not vary linearly with jute fiber content.

  15. Finite element modeling of reinforced concrete structures strengthened with FRP laminates : final report.

    Science.gov (United States)

    2001-05-01

    Linear and non-linear finite element method models were developed for a reinforced concrete bridge that had been strengthened with fiber reinforced polymer composites. ANSYS and SAP2000 modeling software were used; however, most of the development ef...

  16. Research notes : non-destructive evaluation of FRP-strengthened reinforced concrete.

    Science.gov (United States)

    2005-04-01

    Many reinforced concrete structures across the country are being strengthened with fiber reinforced polymer (FRP) composites to increase the load capacity. In many cases, composites provide the most cost effective strengthening option, and they do no...

  17. Synthesis and characterization of chitosan-multiwalled carbon nanotubes/hydroxyapatite nanocomposites for bone tissue engineering.

    Science.gov (United States)

    Chen, Li; Hu, Jingxiao; Shen, Xinyu; Tong, Hua

    2013-08-01

    Chitosan-multiwalled carbon nanotubes/hydroxyapatite nanocomposites were synthesized by a novel in situ precipitation method. The electrostatic adsorption between multiwalled carbon nanotubes and chitosan was investigated and explained by Fourier transform infrared spectroscopy analysis. Morphology studies showed that uniform distribution of hydroxyapatite particles and multiwalled carbon nanotubes in the polymer matrix was observed. In chitosan-multiwalled carbon nanotubes/hydroxyapatite nanocomposites, the diameters of multiwalled carbon nanotubes were about 10 nm. The mechanical properties of the composites were evaluated by measuring their compressive strength and elastic modulus. The elastic modulus and compressive strength increased sharply from 509.9 to 1089.1 MPa and from 33.2 to 105.5 MPa with an increase of multiwalled carbon/chitosan weight ratios from 0 to 5 %, respectively. Finally, the cell biocompatibility of the composites was tested in vitro, which showed that they have good biocompatibility. These results suggest that the chitosan-multiwalled carbon nanotubes/hydroxyapatite nanocomposites are promising biomaterials for bone tissue engineering.

  18. Enhanced osteoconductivity of sodium-substituted hydroxyapatite by system instability.

    Science.gov (United States)

    Sang Cho, Jung; Um, Seung-Hoon; Su Yoo, Dong; Chung, Yong-Chae; Hye Chung, Shin; Lee, Jeong-Cheol; Rhee, Sang-Hoon

    2014-07-01

    The effect of substituting sodium for calcium on enhanced osteoconductivity of hydroxyapatite was newly investigated. Sodium-substituted hydroxyapatite was synthesized by reacting calcium hydroxide and phosphoric acid with sodium nitrate followed by sintering. As a control, pure hydroxyapatite was prepared under identical conditions, but without the addition of sodium nitrate. Substitution of calcium with sodium in hydroxyapatite produced the structural vacancies for carbonate ion from phosphate site and hydrogen ion from hydroxide site of hydroxyapatite after sintering. The total system energy of sodium-substituted hydroxyapatite with structural defects calculated by ab initio methods based on quantum mechanics was much higher than that of hydroxyapatite, suggesting that the sodium-substituted hydroxyapatite was energetically less stable compared with hydroxyapatite. Indeed, sodium-substituted hydroxyapatite exhibited higher dissolution behavior of constituent elements of hydroxyapatite in simulated body fluid (SBF) and Tris-buffered deionized water compared with hydroxyapatite, which directly affected low-crystalline hydroxyl-carbonate apatite forming capacity by increasing the degree of apatite supersaturation in SBF. Actually, sodium-substituted hydroxyapatite exhibited markedly improved low-crystalline hydroxyl-carbonate apatite forming capacity in SBF and noticeably higher osteoconductivity 4 weeks after implantation in calvarial defects of New Zealand white rabbits compared with hydroxyapatite. In addition, there were no statistically significant differences between hydroxyapatite and sodium-substituted hydroxyapatite on cytotoxicity as determined by BCA assay. Taken together, these results indicate that sodium-substituted hydroxyapatite with structural defects has promising potential for use as a bone grafting material due to its enhanced osteoconductivity compared with hydroxyapatite. © 2013 Wiley Periodicals, Inc.

  19. Photo-Healable Metallosupramolecular Polymers

    Science.gov (United States)

    2014-01-09

    Ohio Invited Lecture: Structurally Dynamic Polymers as a Route to Stimuli-Responsive Materials Apr. 2013 ACS PMSE /Chinese Chemical Society meeting...Mark Burnworth, Liming Tang, Stuart J. Rowan, Christoph Weder. Reinforcement of Self- Healing Polymer Films with Cellulose Nanowhiskers, ACS PMSE

  20. Biodegradable and Biocompatible Systems Based on Hydroxyapatite Nanoparticles

    Directory of Open Access Journals (Sweden)

    Pau Turon

    2017-01-01

    Full Text Available Composites of hydroxyapatite (HAp are widely employed in biomedical applications due to their biocompatibility, bioactivity and osteoconductivity properties. In fact, the development of industrially scalable hybrids at low cost and high efficiency has a great impact, for example, on bone tissue engineering applications and even as drug delivery systems. New nanocomposites constituted by HAp nanoparticles and synthetic or natural polymers with biodegradable and biocompatible characteristics have constantly been developed and extensive works have been published concerning their applications. The present review is mainly focused on both the capability of HAp nanoparticles to encapsulate diverse compounds as well as the preparation methods of scaffolds incorporating HAp. Attention has also been paid to the recent developments on antimicrobial scaffolds, bioactive membranes, magnetic scaffolds, in vivo imaging systems, hydrogels and coatings that made use of HAp nanoparticles.

  1. Silk fibroin/hydroxyapatite composites for bone tissue engineering.

    Science.gov (United States)

    Farokhi, Mehdi; Mottaghitalab, Fatemeh; Samani, Saeed; Shokrgozar, Mohammad Ali; Kundu, Subhas C; Reis, Rui L; Fatahi, Yousef; Kaplan, David L

    2017-10-07

    Silk fibroin (SF) is a natural fibrous polymer with strong potential for many biomedical applications. SF has attracted interest in the field of bone tissue engineering due to its extraordinary characteristics in terms of elasticity, flexibility, biocompatibility and biodegradability. However, low osteogenic capacity has limited applications for SF in the orthopedic arena unless suitably functionalized. Hydroxyapatite (HAp) is a well-established bioceramic with biocompatibility and appropriate for constructing orthopedic and dental substitutes. However, HAp ceramics tend to be brittle which can restrict applications in the repair of load-bearing tissues such as bones. Therefore, blending SF and HAp combines the useful properties of both materials as bone constructs for tissue engineering, the subject of this review. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Biomimetic hydroxyapatite particulate nanofiber modified silicon: in vitro bioactivity.

    Science.gov (United States)

    Aryal, Santosh; Bajgai, Madhab Prasad; Khil, Myung Seob; Kang, Hyung-Sub; Kim, Hak Yong

    2009-02-01

    A novel particulate nanofibrous hydroxyapatite (HA), which mimics the bone matrix, is presented as a surface functional material to modify silicon wafers by the electrospinning method. The HA precursors were treated with viscous polymer solution, and then electrospun under controlled conditions. After successive calcinations, the powder X-ray diffraction patterns of the samples revealed reflection toward the (300) HA plane that is linear with temperature. This prominent reflection suggests the crystallographic purity of the HA. Biocompatibility, cell proliferation, and microstructure were examined using AFM and FE-SEM. Morphology showed cell spreading and penetration instead of cell aggregation. The surface roughness as well as adhesion force was calculated using contact mode AFM. The results show that the composite matrix holds promise for use as a bone implant material.

  3. Modelling anisotropic water transport in polymer composite ...

    Indian Academy of Sciences (India)

    This work reports anisotropic water transport in a polymer composite consisting of an epoxy matrix reinforced with aligned triangular bars made of vinyl ester. By gravimetric experiments, water diffusion in resin and polymer composites were characterized. Parameters for Fickian diffusion and polymer relaxation models were ...

  4. Modelling anisotropic water transport in polymer composite ...

    Indian Academy of Sciences (India)

    Abstract. This work reports anisotropic water transport in a polymer composite consisting of an epoxy matrix reinforced with aligned triangular bars made of vinyl ester. By gravimetric experiments, water diffusion in resin and polymer composites were characterized. Parameters for Fickian diffusion and polymer relaxation ...

  5. Improving Fatigue Strength of polymer concrete using nanomaterials.

    Science.gov (United States)

    2016-11-30

    Polymer concrete (PC) is that type of concrete where the cement binder is replaced with polymer. PC is often used to improve friction and protect structural substrates in reinforced concrete and orthotropic steel bridges. However, its low fatigue per...

  6. The comparison study of bioactivity between composites containing synthetic non-substituted and carbonate-substituted hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Borkowski, Leszek, E-mail: leszek.borkowski@umlub.pl [Chair and Department of Biochemistry and Biotechnology, Medical University of Lublin, Chodźki 1, 20-093 Lublin (Poland); Sroka-Bartnicka, Anna [Department of Biopharmacy, Medical University of Lublin, Chodźki 4a, 20-093 Lublin (Poland); Drączkowski, Piotr [Department of Synthesis and Chemical Technology of Pharmaceutical Substances, Medical University of Lublin, Chodźki 4a, 20-093 Lublin (Poland); Ptak, Agnieszka [Chair and Department of Biochemistry and Biotechnology, Medical University of Lublin, Chodźki 1, 20-093 Lublin (Poland); Zięba, Emil [SEM Laboratory, Department of Zoology and Ecology, John Paul II Catholic University of Lublin, Al. Kraśnicka 102, 20-718 Lublin (Poland); Ślósarczyk, Anna [Faculty of Materials Science and Ceramics, AGH-University of Science and Technology, Mickiewicza 30, 30-059 Krakow (Poland); Ginalska, Grażyna [Chair and Department of Biochemistry and Biotechnology, Medical University of Lublin, Chodźki 1, 20-093 Lublin (Poland)

    2016-05-01

    Apatite forming ability of hydroxyapatite (HAP) and carbonate hydroxyapatite (CHAP) containing composites was compared. Two composite materials, intended for filling bone defects, were made of polysaccharide polymer and one of two types of hydroxyapatite. The bioactivity of the composites was evaluated in vitro by soaking in a simulated body fluid (SBF), and the formation of the apatite layer was determined by scanning electron microscopy with energy-dispersive spectrometer and Raman spectroscopy. The results showed that both the composites induced the formation of apatite layer on their surface after soaking in SBF. In addition, the sample weight changes and the ion concentration of the SBF were scrutinized. The results showed the weight increase for both materials after SBF treatment, higher weight gain and higher uptake of calcium ions by HAP containing scaffolds. SBF solution analysis indicated loss of calcium and phosphorus ions during experiment. All these results indicate apatite forming ability of both biomaterials and suggest comparable bioactive properties of composite containing pure hydroxyapatite and carbonate-substituted one. - Highlights: • Bioactivity of two calcium phosphates (HAP and CHAP) was compared. • Two novel ceramic-polymer composite materials were developed. • We examined apatite forming ability of scaffolds in SBF solution. • We report comparable bioactive properties between both materials.

  7. Synthesis, characterization and biocompatibility evaluation of hydroxyapatite - gelatin polyLactic acid ternary nanocomposite

    Directory of Open Access Journals (Sweden)

    Z. Nabipour

    2016-04-01

    Full Text Available Objective(s: The current study reports the production and biocompatibility evaluation of a ternary nanocomposite consisting of HA, PLA, and gelatin for biomedical application.Materials and Methods: Hydroxyapatite nanopowder (HA: Ca10(PO46(OH2 was produced by burning the bovine cortical bone within the temperature range of 350-450 oC followed by heating in an oven at 800. Synthesis of the ternary nanocomposite was carried out in two steps: synthesis of gelatin-hydroxyapatite binary nanocomposite and addition of poly lactic acid with different percentages to the resulting composition. The crystal structure was determined by X-ray diffraction (XRD, while major elements and impurities of hydroxyapatite were identified by elemental analysis of X-ray fluorescence (XRF. Functional groups were determined by Fourier transform infrared spectroscopy (FTIR. Morphology and size of the nanocomposites were evaluated using field emission scanning electron microscope (FE-SEM.Biocompatibility of nanocomposites was investigated by MTT assay. Results: XRD patterns verified the ideal crystal structure of the hydroxyapatite, which indicated an appropriate synthesis process and absence of disturbing phases. Results of FTIR analysis determined the polymers’ functional groups, specified formation of the polymers on the hydroxyapatite surface, and verified synthesis of nHA/PLA/Gel composite. FESEM images also indicated the homogeneous structure of the composite in the range of 50 nanometers. MTT assay results confirmed the biocompatibility of nanocomposite samples.Conclusion: This study suggested that the ternary nanocomposite of nHA/PLA/Gel can be a good candidate for biomedical application such as drug delivery systems, but for evaluation of its potential in hard tissue replacement, mechanical tests should be performed.

  8. Nanocomposite materials based on hydroxyapatite and sodium alginate: synthesis and characteristics

    Directory of Open Access Journals (Sweden)

    О. О. Мартинюк

    2015-10-01

    Full Text Available This work is devoted to the development and optimization of the synthesis methodof nanostructured biopolymer-apatite composite materials for medical applications with different ratios of polymer (sodium alginate, SA and inorganic (hydroxyapatite, HA phases and research their properties. Composition, structure and morphology of the samples by FTIR spectroscopy, X-ray diffraction and transmission electron microscopy (TEM were characterized. Porosity, degree of swelling and in vitro response on bioactivity in physiological solution obtained compositesweredetermined. The formation in the presence of sodium alginate hydroxyapatite phase with needle structure and average crystallite size 23 nm with simultaneous formation biopolymer matrix due to the interaction of positively charged calcium ions (Ca2+ and negatively charged carboxyl groups (COO- by instrumental methodswasconfirmed. The pH changing of physiological solution in the presence of samples testifies their bioactivit

  9. Synthesis and Characterization of Hydroxyapatite/Fullerenol Nanocomposites.

    Science.gov (United States)

    Djordjevic, Aleksandar; Ignjatovic, Nenad; Seke, Mariana; Jovic, Danica; Uskokovic, Dragan; Rakocevic, Zlatko

    2015-02-01

    Fullerenols are polyhydroxylated, water soluble derivatives of fullerene C60, with potential application in medicine as diagnostic agents, antioxidants or nano drug carriers. This paper describes synthesis and physical characterization of a new nanocomposite hydroxyapatite/fullerenol. Surface of the nanocomposite hydroxyapatite/fullerenol is inhomogeneous with the diameter of the particles in the range from 100 nm to 350 nm. The ζ potential of this nanocomposite is ten times lower when compared to hydroxyapatite. Surface phosphate groups of hydroxyapatite are prone to forming hydrogen bonds, when in close contact with hydroxyl groups, which could lead to formation of hydrogen bonds between hydroxyapatite and hydroxyl groups of fullerenol. The surface of hydroxyapatite particles (-2.5 mV) was modified by fullerenol particles, as confirmed by the obtained ζ potential value of the nanocomposite biomaterial hydroxyapatite/fullerenol (-25.0 mV). Keywords: Hydroxyapatite, Fullerenol, Nanocomposite, Surface Analysis.

  10. The Effect of Zirconia in Hydroxyapatite on Staphylococcus epidermidis Growth

    Directory of Open Access Journals (Sweden)

    Widowati Siswomihardjo

    2012-01-01

    . Conclusion. The addition of zirconia into hydroxyapatite affected the growth of S. epidermidis. Hydroxyapatite with 20% zirconia proved to be an effective concentration to inhibit the growth of S. epidermidis colony.

  11. GLASS-FIBRE REINFORCED COMPOSITES: THE EFFECT OF ...

    African Journals Online (AJOL)

    HOD

    materials in many engineering application have enhanced the corrosion resistance and improved strength of ... glass fibre in various engineering practises, only restricted information is available on the application of ..... fiber reinforced polymer composites for automobile accessories," American Journal of Environmental.

  12. Behavior of concrete specimens reinforced with composite materials : laboratory study

    Science.gov (United States)

    2000-02-01

    The main objective of this study was to investigate the interaction between FRP composite and concrete by addressing the most important : variables in terms of FRP (fiber reinforced polymer) properties. Type of fibers, thickness of the laminates, fib...

  13. Surface Modification of Exfoliated Graphite Nano-Reinforcements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Nano forms of graphite and carbon, such as flakes, worms, and tubes, can significantly modify the properties of polymers when used as reinforcements. Challenges...

  14. Drastic Improvements in Bonding of Fiber Reinforced Multifunctional Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Achievement of a dramatic increase in the bond strength in the composite/adhesive interfaces of existing fiber reinforced polymer (FRP) composite material joints and...

  15. REINFORCED COMPOSITE PANEL

    DEFF Research Database (Denmark)

    2003-01-01

    A composite panel having front and back faces, the panel comprising facing reinforcement, backing reinforcement and matrix material binding to the facing and backing reinforcements, the facing and backing reinforcements each independently comprising one or more reinforcing sheets, the facing...... by matrix material, the facing and backing reinforcements being interconnected to resist out-of-plane relative movement. The reinforced composite panel is useful as a barrier element for shielding structures, equipment and personnel from blast and/or ballistic impact damage....

  16. Characteristics of porous zirconia coated with hydroxyapatite as ...

    Indian Academy of Sciences (India)

    Since hydroxyapatite has excellent biocompatibility and bone bonding ability, porous hydroxyapatite ceramics have been intensively studied. However, porous hydroxyapatite bodies are mechanically weak and brittle, which makes shaping and implantation difficult. One way to solve this problem is to introduce a strong ...

  17. Durability of GFRP reinforcing bars and their bond in concrete

    OpenAIRE

    Rolland, Arnaud; Chataigner, Sylvain; Quiertant, Marc; Benzarti, Karim; Argoul, Pierre

    2015-01-01

    The use of composite reinforcing bars (rebars) for the reinforcement of concrete appears as an attractive solution to prevent corrosion, which is the main pathology encountered on concrete structures. Although such rebars are being used for more than ten years, there is a clear lack of knowledge regarding their durability, especially under alkaline environment. This paper aims at investigating the evolutions of tensile properties and bond in concrete of GFRP (Glass Fiber Reinforced Polymer...

  18. 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.

  19. Characterization,Mechanical, and In Vitro Bioactivity Properties of Hydroxyapatite/Bioactive Glass Composite

    Directory of Open Access Journals (Sweden)

    Israa Kahatan Sabree

    2016-12-01

    Full Text Available Bioactive ceramic materials can help bone reparation and regeneration by offering support to bone growth. Biological hydroxyapatite powder was prepared by burning animal bone followed by studying the mechanical properties of hydroxyapatite (HA/ (20wt.%, and 40wt.% of binary bioactive glass (70% SiO2- 30% CaO in order to evaluate the influence of composition on the compressive strength and hardness. HA-composite material exhibited increasing density, microhardness, and compressive strength with increasing amount of glass addition. X-ray diffraction after sintering at 1200°C showed no alter of HA to secondary phases while the hydroxyapatite/ bioactive glass composites contained a HA phase and different amounts of wollastonite phase, depending on the amount of bioglass added. In vitro tests, the samples were soaked in simulated body fluid (SBF for ten days in order to evaluate the change in compression strength, weight loss, and pH. The HA composite reinforced with 40 wt % bioglass showed highest compression strength, and lowest weight loss

  20. Testing of full-size reinforced concrete beams strengthened with FRP composites : experimental results and design methods verification

    Science.gov (United States)

    2000-06-01

    In 1997, a load rating of an historic reinforced concrete bridge in Oregon, Horsetail Creek Bridge, indicated substandard shear and moment capacities of the beams. As a result, the Bridge was strengthened with fiber reinforced : polymer composites as...