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Sample records for composite structures crada

  1. CRADA Final Report for CRADA No. ORNL99-0544, Interfacial Properties of Electron Beam Cured Composites

    Energy Technology Data Exchange (ETDEWEB)

    Janke, C.J.

    2005-10-17

    Electron beam (EB) curing is a technology that promises, in certain applications, to deliver lower cost and higher performance polymer matrix composite (PMC) structures compared to conventional thermal curing processes. PMCs enhance performance by making products lighter, stronger, more durable, and less energy demanding. They are essential in weight- and performance-dominated applications. Affordable PMCs can enhance US economic prosperity and national security. US industry expects rapid implementation of electron beam cured composites in aircraft and aerospace applications as satisfactory properties are demonstrated, and implementation in lower performance applications will likely follow thereafter. In fact, at this time and partly because of discoveries made in this project, field demonstrations are underway that may result in the first fielded applications of electron beam cured composites. Serious obstacles preventing the widespread use of electron beam cured PMCs in many applications are their relatively poor interfacial properties and resin toughness. The composite shear strength and resin toughness of electron beam cured carbon fiber reinforced epoxy composites were about 25% and 50% lower, respectively, than those of thermally cured composites of similar formulations. The essential purpose of this project was to improve the mechanical properties of electron beam cured, carbon fiber reinforced epoxy composites, with a specific focus on composite shear properties for high performance aerospace applications. Many partners, sponsors, and subcontractors participated in this project. There were four government sponsors from three federal agencies, with the US Department of Energy (DOE) being the principal sponsor. The project was executed by Oak Ridge National Laboratory (ORNL), NASA and Department of Defense (DOD) participants, eleven private CRADA partners, and two subcontractors. A list of key project contacts is provided in Appendix A. In order to properly

  2. Micromagnetic Code Development of Advanced Magnetic Structures Final Report CRADA No. TC-1561-98

    Energy Technology Data Exchange (ETDEWEB)

    Cerjan, Charles J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shi, Xizeng [Read-Rite Corporation, Fremont, CA (United States)

    2017-11-09

    The specific goals of this project were to: Further develop the previously written micromagnetic code DADIMAG (DOE code release number 980017); Validate the code. The resulting code was expected to be more realistic and useful for simulations of magnetic structures of specific interest to Read-Rite programs. We also planned to further the code for use in internal LLNL programs. This project complemented LLNL CRADA TC-840-94 between LLNL and Read-Rite, which allowed for simulations of the advanced magnetic head development completed under the CRADA. TC-1561-98 was effective concurrently with LLNL non-exclusive copyright license (TL-1552-98) to Read-Rite for DADIMAG Version 2 executable code.

  3. Design and fabrication of a prototype sensor system for waste storage tank characterization. CRADA final report for CRADA Number ORNL92-0094

    International Nuclear Information System (INIS)

    Burks, B.L.; Wagner, J.

    1994-01-01

    On February 15--16 1994, ORNL and MTI presented a technology demonstration showcasing the results of a CRADA between the two organizations. The CRADA project entailed design and development of a structured light mapping system suitable for deployment in underground waste storage tanks. The CRADA expanded upon a system previously designed and deployed at the DOE Fernald site by ORNL. Enhancements in the new system include: a factor of ten increase in mapping speed; radiation and environmental hardening sufficient for use in the Hanford single-shell tanks (up to 5,000 rad/hr, pH = 12, high heat, etc.); capability to map and display data for both vertical surfaces, such as pipes, and horizontal surfaces; rugged, compact design that can be deployed through a ten centimeter riser; and a design that can be decontaminated easily after deployment

  4. High Performance Parallel Processing (HPPP) Finite Element Simulation of Fluid Structure Interactions Final Report CRADA No. TC-0824-94-A

    Energy Technology Data Exchange (ETDEWEB)

    Couch, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ziegler, D. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2018-01-24

    This project was a muki-partner CRADA. This was a partnership between Alcoa and LLNL. AIcoa developed a system of numerical simulation modules that provided accurate and efficient threedimensional modeling of combined fluid dynamics and structural response.

  5. CRADA FINAL REPORT FOR CRADA010393:

    OpenAIRE

    Weber, Adam Z.

    2016-01-01

    This CRADA is established to jointly develop H2/Br2 flow batteries with improved materials sets and understanding between TVN Systems and LBNL. The focus of the activities is the testing and optimization of flow battery components to meet efficiency and power requirements. The proposed work is essentially all experimental where TVN Systems will use their knowledge and expertise in membrane-electrode-assembly (MEA) design and fabrication using novel catalyst and membrane materia...

  6. Cooperative Research and Development Agreement Final Report for Cooperative Research and Development Agreement Number ORNL93-0237 Adhesive Bonding Technologies for Automotive Structural Composites; TOPICAL

    International Nuclear Information System (INIS)

    Boeman, R.G.

    2001-01-01

    In 1993, the Oak Ridge National Laboratory (ORNL) entered into a Cooperative Research and Development Agreement (CRADA) with the Automotive Composites Consortium (ACC) to conduct research and development that would overcome technological hurdles to the adhesive bonding of current and future automotive materials. This effort is part of a larger Department of Energy (DOE) program to promote the use of lighter weight materials in automotive structures for the purpose of increasing fuel efficiency and reducing environmental pollutant emissions. In accomplishing this mission, the bonding of similar and dissimilar materials was identified as being of primary importance to the automotive industry since this enabling technology would give designers the freedom to choose from an expanded menu of low mass materials for component weight reduction. The research undertaken under this CRADA addresses the following areas of importance: bulk material characterization, structural fracture mechanics, modeling/characterization, process control and nondestructive evaluation (PC/NDE), manufacturing demonstration, and advanced processing. For the bulk material characterization task, the individual material properties of the adherends and adhesives were characterized. This included generating a database of mechanical and physical properties, after identifying and developing standard test methods to obtain properties. The structural fracture mechanics task concentrated on test development to characterize the fracture toughness of adhesively bonded joints subjected to Mode I, Mode II and mixed-mode conditions. Standard test procedures for quantifying an adhesive/adherend system's resistance to crack growth were developed for use by industry. In the modeling/characterization task, fracture mechanics-based design guidelines and predictive methodologies have been developed which will facilitate iteration on design concepts for bonded joints while alleviating the need for extensive testing

  7. CRADAs: They're Not Just for NCI Anymore | Poster

    Science.gov (United States)

    By Karen Surabian, Thomas Stackhouse, and Jeffrey Thomas, Contributing Writers, and Bruce Crise, Guest Writer Advancing scientific discovery is increasingly dependent on diverse and innovative partnerships, and the Cooperative Research and Development Agreement (CRADA) is an essential tool for establishing partnerships. CRADAs allow a federal laboratory to enter into collaborative research and development (R&D) projects with outside parties (commercial or nonprofit).

  8. Rapid response manufacturing (RRM). Final CRADA report

    Energy Technology Data Exchange (ETDEWEB)

    Cain, W.D. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States); Waddell, W.L. [National Centers for Manufacturing Sciences, Ann Arbor, MI (United States)

    1998-02-10

    US industry is fighting to maintain its competitive edge in the global market place. Markets fluctuate rapidly. Companies have to be able to respond quickly with improved, high quality, cost efficient products. Because companies and their suppliers are geographically distributed, rapid product realization is dependent on the development of a secure integrated concurrent engineering environment operating across multiple business entities. The way products are developed and brought to market can be improved and made more efficient through the proper incorporation of emerging technologies implemented in a secure environment. This documents the work done under this CRADA to develop capabilities, which permit the effective application, incorporation, and use of advanced technologies in a secure environment to facilitate the product realization process. Lockheed Martin Energy Systems (LMES), through a CRADA with the National Center for Manufacturing Sciences (NCMS), worked within a consortium of major industrial firms--Ford, General Motors, Texas Instruments, United Technologies, and Eastman Kodak--and several small suppliers of advanced manufacturing technology--MacNeal-Schwendler Corp., Teknowledge Corp., Cimplex Corp., Concentra, Spatial Technology, and Structural Dynamics Research Corp. (SDRC)--to create infrastructure to support the development and implementation of secure engineering environments for Rapid Response Manufacturing. The major accomplishment achieved under this CRADA was the demonstration of a prototypical implementation of a broad-based generic framework for automating and integrating the design-to-manufacturing activities associated with machined parts in a secure NWC compliant environment. Specifically, methods needed to permit the effective application, incorporation, and use of advanced technologies in a secure environment to facilitate the product realization process were developed and demonstrated. An important aspect of this demonstration was

  9. A national laboratory/private industry cooperative research and development agreement (CRADA)

    International Nuclear Information System (INIS)

    Pritchard, D.A.

    1996-01-01

    This paper provides an overview of the history and process of establishing a cooperative research and development agreement (CRADA) between Sandia National Laboratories and Magnavox Electronic Systems Company for the design, development, and testing of a 360-degree scanning, imaging, intrusion detection sensor. The subject of the CRADA is the Advanced Exterior Sensor (AES). It is intended for exterior use at ranges from 50 to 1,500 meters and uses a combination of three sensing technologies (infrared, visible, and radar) and a new data processing method to provide low false-alarm intrusion detection and tracking combined with immediate visual assessment. The establishment of this CRADA represents a new paradigm in the cooperation between the Department of Defense, the Department of Energy, the National Laboratories and Private Industry. Although a formal document has now been executed, a CRADA is, nonetheless, primarily an agreement to work with each other to achieve goals that might otherwise be unattainable. For the DoD, a program continues in the face of uncertain funding. For the DOE, a CRADA is in place that meets congressionally mandated guidelines. For Sandia, sponsors are in agreement on requirements and synergistic funding. And for Magnavox, an opportunity is in hand to work with researchers in developing advanced security technology

  10. Biodiesel/Cummins CRADA Report

    Science.gov (United States)

    2014-07-01

    dedicated totes). This change provided uncontaminated containers to transport the delivery of biodiesel to the ANT, and better control for dosing as...emissions calculations. Each approach makes assumptions for farming practices, the biodiesel production process, and transportation and distribution... Biodiesel /Cummins CRADA Report Distribution Statement A: Approved for Public Release; distribution is unlimited. July 2014 Report

  11. Electron beam curing of polymer matrix composites

    International Nuclear Information System (INIS)

    Janke, C.J.; Wheeler, D.; Saunders, C.

    1998-01-01

    The purpose of the CRADA was to conduct research and development activities to better understand and utilize the electron beam PMC curing technology. This technology will be used to replace or supplement existing PMC thermal curing processes in Department of Energy (DOE) Defense Programs (DP) projects and American aircraft and aerospace industries. This effort involved Lockheed Martin Energy Systems, Inc./Lockheed Martin Energy Research Corp. (Contractor), Sandia National Laboratories, and ten industrial Participants including four major aircraft and aerospace companies, three advanced materials companies, and three electron beam processing organizations. The technical objective of the CRADA was to synthesize and/or modify high performance, electron beam curable materials that meet specific end-use application requirements. There were six tasks in this CRADA including: Electron beam materials development; Electron beam database development; Economic analysis; Low-cost Electron Beam tooling development; Electron beam curing systems integration; and Demonstration articles/prototype structures development. The contractor managed, participated and integrated all the tasks, and optimized the project efforts through the coordination, exchange, and dissemination of information to the project participants. Members of the Contractor team were also the principal inventors on several electron beam related patents and a 1997 R and D 100 Award winner on Electron-Beam-Curable Cationic Epoxy Resins. The CRADA achieved a major breakthrough for the composites industry by having successfully developed high-performance electron beam curable cationic epoxy resins for use in composites, adhesives, tooling compounds, potting compounds, syntactic foams, etc. UCB Chemicals, the world's largest supplier of radiation-curable polymers, has acquired a license to produce and sell these resins worldwide

  12. Exploring synchrotron radiation capabilities: The ALS-Intel CRADA

    International Nuclear Information System (INIS)

    Gozzo, F.; Cossy-Favre, A.; Padmore, H.

    1997-01-01

    Synchrotron radiation spectroscopy and spectromicroscopy were applied, at the Advanced Light Source, to the analysis of materials and problems of interest to the commercial semiconductor industry. The authors discuss some of the results obtained at the ALS using existing capabilities, in particular the small spot ultra-ESCA instrument on beamline 7.0 and the AMS (Applied Material Science) endstation on beamline 9.3.2. The continuing trend towards smaller feature size and increased performance for semiconductor components has driven the semiconductor industry to invest in the development of sophisticated and complex instrumentation for the characterization of microstructures. Among the crucial milestones established by the Semiconductor Industry Association are the needs for high quality, defect free and extremely clean silicon wafers, very thin gate oxides, lithographies near 0.1 micron and advanced material interconnect structures. The requirements of future generations cannot be met with current industrial technologies. The purpose of the ALS-Intel CRADA (Cooperative Research And Development Agreement) is to explore, compare and improve the utility of synchrotron-based techniques for practical analysis of substrates of interest to semiconductor chip manufacturing. The first phase of the CRADA project consisted in exploring existing ALS capabilities and techniques on some problems of interest. Some of the preliminary results obtained on Intel samples are discussed here

  13. Surface Inspection Machine Infrared (SIMIR). Final CRADA report

    Energy Technology Data Exchange (ETDEWEB)

    Powell, G.L. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States); Neu, J.T.; Beecroft, M. [Surface Optics Corp., San Diego, CA (United States)

    1997-02-28

    This Cooperative Research and Development Agreement was a one year effort to make the surface inspection machine based on diffuse reflectance infrared spectroscopy (Surface Inspection Machine-Infrared, SIMIR), being developed by Surface Optics Corporation, perform to its highest potential as a practical, portable surface inspection machine. The design function of the SIMIR is to inspect metal surfaces for cleanliness (stains). The system is also capable of evaluating graphite-resin systems for cure and heat damage, and for measuring the effects of moisture exposure on lithium hydride, corrosion on uranium metal, and the constituents of and contamination on wood, paper, and fabrics. Over the period of the CRADA, extensive experience with the use of the SIMIR for surface cleanliness measurements have been achieved through collaborations with NASA and the Army. The SIMIR was made available to the AMTEX CRADA for Finish on Yarn where it made a very significant contribution. The SIMIR was the foundation of a Forest Products CRADA that was developed over the time interval of this CRADA. Surface Optics Corporation and the SIMIR have been introduced to the chemical spectroscopy on-line analysis market and have made staffing additions and arrangements for international marketing of the SIMIR as an on-line surface inspection device. LMES has been introduced to a wide range of aerospace applications, the research and fabrication skills of Surface Optics Corporation, has gained extensive experience in the areas of surface cleanliness from collaborations with NASA and the Army, and an extensive introduction to the textile and forest products industries. The SIMIR, marketed as the SOC-400, has filled an important new technology need in the DOE-DP Enhanced Surveillance Program with instruments delivered to or on order by LMES, LANL, LLNL, and Pantex, where extensive collaborations are underway to implement and improve this technology.

  14. Surface Inspection Machine Infrared (SIMIR). Final CRADA report

    International Nuclear Information System (INIS)

    Powell, G.L.; Neu, J.T.; Beecroft, M.

    1997-01-01

    This Cooperative Research and Development Agreement was a one year effort to make the surface inspection machine based on diffuse reflectance infrared spectroscopy (Surface Inspection Machine-Infrared, SIMIR), being developed by Surface Optics Corporation, perform to its highest potential as a practical, portable surface inspection machine. The design function of the SIMIR is to inspect metal surfaces for cleanliness (stains). The system is also capable of evaluating graphite-resin systems for cure and heat damage, and for measuring the effects of moisture exposure on lithium hydride, corrosion on uranium metal, and the constituents of and contamination on wood, paper, and fabrics. Over the period of the CRADA, extensive experience with the use of the SIMIR for surface cleanliness measurements have been achieved through collaborations with NASA and the Army. The SIMIR was made available to the AMTEX CRADA for Finish on Yarn where it made a very significant contribution. The SIMIR was the foundation of a Forest Products CRADA that was developed over the time interval of this CRADA. Surface Optics Corporation and the SIMIR have been introduced to the chemical spectroscopy on-line analysis market and have made staffing additions and arrangements for international marketing of the SIMIR as an on-line surface inspection device. LMES has been introduced to a wide range of aerospace applications, the research and fabrication skills of Surface Optics Corporation, has gained extensive experience in the areas of surface cleanliness from collaborations with NASA and the Army, and an extensive introduction to the textile and forest products industries. The SIMIR, marketed as the SOC-400, has filled an important new technology need in the DOE-DP Enhanced Surveillance Program with instruments delivered to or on order by LMES, LANL, LLNL, and Pantex, where extensive collaborations are underway to implement and improve this technology

  15. Development of a Commercial Prototype of the Autonomous Pathogen Detection System Final Report CRADA No. TC-02077-04

    Energy Technology Data Exchange (ETDEWEB)

    Dzenitis, J. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Haigh, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-27

    This was a collaborative effort between The Regents of the University of California, Lawrence Livermore National Laboratory (LLNL), and GE Ion Track, Inc. (GEIT) to develop a commercial prototype of the Autonomous Pathogen Detection System (APDS), an instrument that monitors the air for all three biological threat agents (bacteria, viruses and toxins). This was originally a one year CRADA project, with the cost of the work at LLNL being funded by the Department of Homeland Security's Office of National Laboratories. The original project consisted of five major tasks and deliverables. The CRADA was then amended, converting the CRADA from a programmatically funded CRADA to a funds-in CRADA, extending the project for an additional 14 months, and adding four new tasks and deliverable to the project.

  16. Hydrothermal Liquefaction of Agricultural and Biorefinery Residues Final Report – CRADA #PNNL/277

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.; Neuenschwander, Gary G.; Hart, Todd R.; Rotness, Leslie J.; Zacher, Alan H.; Fjare, K. A.; Dunn, B. C.; McDonald, S. L.; Dassor, G.

    2010-07-28

    This project was performed as a Cooperative Research and Development Agreement (CRADA) with the participants: Archer-Daniels-Midland Company (ADM), ConocoPhillips (COP), and Pacific Northwest National Laboratory (PNNL). Funding from the federal government was provided by the Office of the Biomass Program within the Energy Efficiency and Renewable Energy assistant secretariat as part of the Thermochemical Conversion Platform. The three-year project was initiated in August 2007 with formal signing of the CRADA (#PNNL/277) in March 3, 2008 with subsequent amendments approved in November of 2008 and August of 2009. This report describes the results of the work performed by PNNL and the CRADA partners ADM and COP. It is considered Protected CRADA Information and is not available for public disclosure. The work conducted during this project involved developing process technology at PNNL for hydrothermal liquefaction (HTL) of agricultural and biorefinery residues and catalytic hydrothermal gasification (CHG) of the aqueous byproduct from the liquefaction step. Related work performed by the partners included assessment of aqueous phase byproducts, hydroprocessing of the bio-oil product and process analysis and economic modeling of the technology.

  17. Development of Charge Drain Coatings: Final CRADA Report

    Energy Technology Data Exchange (ETDEWEB)

    Elam, Jeffrey W. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-01-17

    The primary goal of this CRADA project was to develop and optimize tunable resistive coatings prepared by atomic layer deposition (ALD) for use as charge-drain coatings on the KLA-Tencor digital pattern generators (DPGs).

  18. CRADA Payment Options | NCI Technology Transfer Center | TTC

    Science.gov (United States)

    NCI TTC CRADA PAYMENT OPTIONS: Electronic Payments by Wire Transfer via Fedwire, Mail a check to the Institute or Center, or Automated Clearing House (ACH)/Electronic Funds Transfer (ETF) payments via Pay.gov (NCI ONLY).

  19. Development of XRMF techniques for measurement of multi-layer film thicknesses on semiconductors for VLSI and ULSI integrated circuits. Final CRADA report for CRADA number Y-1292-0130

    International Nuclear Information System (INIS)

    Carpenter, D.A.; Golijanin, D.L.; Wherry, D.

    1997-01-01

    A CRADA with Kevex Instruments was carried out to develop improved XRMF instrumentation for the nondestructive analysis of electronic components during manufacture. Experiments conducted at Y-12 proved the feasibility of a new Kevex x-ray tube design. Tests also show that the current commercial supply of straight glass capillaries is unreliable; however, other vendors of tapered single and multiple glass capillaries were identified. The stability of the Y-12 x-ray microprobe was significantly enhanced as a result of this CRADA

  20. 78 FR 28866 - Cooperative Research and Development Agreement (CRADA) Opportunity With the Department of...

    Science.gov (United States)

    2013-05-16

    ... commercialization access to critical assay components such as the recombinant 3ABC* protein (* indicates that the 3C... and Mouth Disease virus (FMDV) non-structural proteins (NSP): 3A, 3B, or 3C. This new FMDV 3ABC ELISA... this CRADA will be to develop and validate the FMDV 3ABC ELISA assay in collaboration with DHS S&T and...

  1. Molecular engineering of polymer alloys: A final report of results obtained on CRADA No. 1078

    Energy Technology Data Exchange (ETDEWEB)

    Curro, J.G. [Sandia National Labs., Albuquerque, NM (United States); Schweizer, K.S. [Univ. of Illinois, Urbana, IL (United States). Dept. of Materials Science and Engineering; Honeycutt, J.D. [BIOSYM Technologies, San Diego, CA (United States)

    1995-12-01

    This report summarizes the technical progress made in the past three years on CRADA No. 1078, Molecular Engineering of Polymer Alloys. The thrust of this CRADA was to start with the basic ideas of PRISM theory and develop it to the point where it could be applied to modeling of polymer alloys. In this program, BIOSYM, Sandia and the University of Illinois worked jointly to develop the theoretical techniques and numerical formalisms necessary to implement the theoretical ideas into commercial software aimed at molecular engineering of polymer alloys. This CRADA focused on developing the techniques required to make the transition from theory to practice. These techniques were then used by BIOSYM to incorporate PRISM theory and other new developments into their commercial software.

  2. In-service testing of Ni{sub 3}Al coupons and trays in carburizing furnaces at Delphi Saginaw. CRADA final report

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.; Santella, M.L.; Viswanathan, S.; Swindeman, R.W. [Oak Ridge National Lab., TN (United States); Chatterjee, M. [General Motors Corporaion, Saginaw Division (United States)

    1998-08-01

    This Cooperative Research and Development Agreement (CRADA) report deals with the development of nickel aluminide alloy for improved longer life heat-resistant fixture assemblies for batch and continuous pusher carburizing furnaces. The nickel aluminide development was compared in both coupon and component testing with the currently used Fe-Ni-Cr heat-resisting alloy known as HU. The specific goals of the CRADA were: (1) casting process development, (2) characterization and possible modification of the alloy composition to optimize its manufacturing ability and performance under typical furnace operating conditions, and (3) testing and evaluation of specimens and prototype fixtures. In support of the CRADA objectives, coupons of nickel aluminide and the HU alloy were installed in both batch and pusher furnaces. The coupons were taken from two silicon levels and contained welds made with two different filler compositions (IC-221LA and IC-221W). Both nickel-aluminide and HU coupons were removed from the batch and pusher carburizing furnace at time intervals ranging from one month to one year. The exposed coupons were cut and mounted for metallographic, hardness, and microprobe analysis. The results of the microstructural analysis have been transmitted to General Motors Corporation, Saginaw Division (Delphi Saginaw) through reports that were presented at periodic CRADA review meetings. Based on coupon testing and verification of the coupon results with the testing of trays, Delphi Saginaw moved forward with the use of six additional trays in a batch furnace and two assemblies in a pusher furnace. Fifty percent of the trays and fixtures are in the as-cast condition and the remaining trays and fixtures are in the preoxidized condition. The successful operating experience of two assemblies in the pusher furnace for nearly a year formed the basis for a production run of 63 more assemblies. The production run required melting of 94 heats weighing 500 lb. each. Twenty

  3. Development of a Landmine Detection Sensor Final Report CRADA No. TC02133.0

    Energy Technology Data Exchange (ETDEWEB)

    Romero, C. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sheppard, C. [First Alliance Technologies, LLC, San Ramon, CA (United States)

    2017-09-06

    This was one of two CRADAs between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and First Alliance Technologies, LLC (First Alliance), to conduct research and development activity toward an integrated system for the detecting, locating, and destroying of landmines and unexploded ordinance using a laser to destroy landmines and unexploded ordinance and First Alliance’s Land Mine Locator (LML) system. The focus of this CRADA was on developing a sensor system that accurately detects landmines, and provides exact location information in a timely manner with extreme reliability.

  4. Electron beam curing of composites in North America

    International Nuclear Information System (INIS)

    Berejka, Anthony J.; Eberle, Cliff

    2002-01-01

    Electron beam curing of fiber-reinforced composites was explored over 30 years ago. Since then there have been developments in accelerator technology, in processes for handling materials presented to an accelerator, and in materials that can be used as matrix binders. In recent years in North America, Cooperative Research and Development Agreements (CRADAs) have been formed involving collaboration amongst materials suppliers, accelerator manufacturers and service providers, national laboratories, such as Oak Ridge National Laboratory, and interested potential users. The scope and status of these CRADAs are reviewed along with other recent developments in the electron beam curing of composites in North America. Innovative and proprietary materials technology has been developed and progress made toward implementing commercial practice. Significant market interest has developed in the military/aerospace industries that are finding the process and performance of electron beam cured composites to offer significant benefits

  5. High Density, Insensitive Oxidizer With RDX Performance Final Report CRADA No. TC02178.0

    Energy Technology Data Exchange (ETDEWEB)

    Pagoria, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Preda, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-25

    This was a collaborative effort between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and Physical Sciences, Inc. (PSI), to develop a synthesis and evaluate a novel high density, insensitive oxidizer with RDX performance. This CRADA resulted from the award of a Phase I STTR ("STTR") from DOD. In recent years, the synthesis of new energetic heterocyclic compounds to replace the energetic materials currently in the stockpile has received a great amount of attention. The Office of the Secretary of Defense has identified that there is a need to incorporate new energetic materials in current and future weapon systems in an effort to increase performance and decrease sensitivity. For many of the future weapon systems, incorporation of energetic compounds currently in the stockpile will not provide the desired performance and sensitivity goals. The success of this CRADA may lead to a Phase I option STTR from DOD and to a Phase II STTR from DOD. The goal of this CRADA was to produce and test a novel oxidizer, 2,5,8-trinitroheptazine (TNH).

  6. Enhanced control and sensing for the REMOTEC ANDROS Mk VI robot. CRADA final report

    International Nuclear Information System (INIS)

    Spelt, P.F.; Harvey, H.W.

    1998-01-01

    This Cooperative Research and Development Agreement (CRADA) between Lockheed Martin Energy Systems, Inc., and REMOTEC, Inc., explored methods of providing operator feedback for various work actions of the ANDROS Mk VI teleoperated robot. In a hazardous environment, an extremely heavy workload seriously degrades the productivity of teleoperated robot operators. This CRADA involved the addition of computer power to the robot along with a variety of sensors and encoders to provide information about the robot's performance in and relationship to its environment. Software was developed to integrate the sensor and encoder information and provide control input to the robot. ANDROS Mk VI robots are presently used by numerous electric utilities to perform tasks in reactors where substantial exposure to radiation exists, as well as in a variety of other hazardous environments. Further, this platform has potential for use in a number of environmental restoration tasks, such as site survey and detection of hazardous waste materials. The addition of sensors and encoders serves to make the robot easier to manage and permits tasks to be done more safely and inexpensively (due to time saved in the completion of complex remote tasks). Prior research on the automation of mobile platforms with manipulators at Oak Ridge National Laboratory's Center for Engineering Systems Advanced Research (CESAR, B ampersand R code KC0401030) Laboratory, a BES-supported facility, indicated that this type of enhancement is effective. This CRADA provided such enhancements to a successful working teleoperated robot for the first time. Performance of this CRADA used the CESAR laboratory facilities and expertise developed under BES funding

  7. Application of a Barrier Filter at a High Purity Synthetic Graphite Plant, CRADA 99-F035, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    National Energy Technology Laboratory

    2000-08-31

    Superior Graphite Company and the US Department of Energy have entered into a Cooperative Research and Development Agreement (CRADA) to study the application of ceramic barrier filters at its Hopkinsville, Kentucky graphite plant. Superior Graphite Company is a worldwide leader in the application of advanced thermal processing technology to produce high purity graphite and carbons. The objective of the CRADA is to determine the technical and economic feasibility of incorporating the use of high-temperature filters to improve the performance of the offgas treatment system. A conceptual design was developed incorporating the ceramic filters into the offgas treatment system to be used for the development of a capital cost estimate and economic feasibility assessment of this technology for improving particulate removal. This CRADA is a joint effort of Superior Graphite Company, Parsons Infrastructure and Technology Group, and the National Energy Technology Laboratory (NETL) of the US Department of Energy (DOE).

  8. Brain Implants for Prediction and Mitigation of Epileptic Seizures - Final CRADA Report

    Energy Technology Data Exchange (ETDEWEB)

    Gopalsami, Nachappa

    2016-09-29

    This is a CRADA final report on C0100901 between Argonne National Laboratory and Flint Hills Scientific, LLC of Lawrence, Kansas. Two brain implantable probes, a surface acoustic wave probe and a miniature cooling probe, were designed, built, and tested with excellent results.

  9. Application of a Barrier Filter at a High Purity Synthetic Graphite Plant, CRADA 99-F035, Final Report; FINAL

    International Nuclear Information System (INIS)

    National Energy Technology Laboratory

    2000-01-01

    Superior Graphite Company and the US Department of Energy have entered into a Cooperative Research and Development Agreement (CRADA) to study the application of ceramic barrier filters at its Hopkinsville, Kentucky graphite plant. Superior Graphite Company is a worldwide leader in the application of advanced thermal processing technology to produce high purity graphite and carbons. The objective of the CRADA is to determine the technical and economic feasibility of incorporating the use of high-temperature filters to improve the performance of the offgas treatment system. A conceptual design was developed incorporating the ceramic filters into the offgas treatment system to be used for the development of a capital cost estimate and economic feasibility assessment of this technology for improving particulate removal. This CRADA is a joint effort of Superior Graphite Company, Parsons Infrastructure and Technology Group, and the National Energy Technology Laboratory (NETL) of the US Department of Energy (DOE)

  10. Pulsed Plasma Processing of Diesel Engine Exhaust Final Report CRADA No. TC-0336-92-1-C

    Energy Technology Data Exchange (ETDEWEB)

    Merritt, Bernard T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Broering, Louis [Cummins Engine Company, Inc., Columbus, IN (United States)

    2017-11-09

    The goal was to develop an exhaust-gas treatment process for the reduction of NOx and hydrocarbon from diesel engines. The project began believing that direct chemical reduction on NOx was possible through the use of non-thermal plasmas. The original CRADA began in 1993 and was scheduled to finish in 1996. It had as its goals three metrics: 1) remove two grams/brake-horse-power-hour of NOx, 2) have no more than five percent energy penalty, and 3) cost no more than ten percent of the engine cost. These goals were all aimed at heavy-duty diesel trucks. This CRADA had its Defense Program funding eliminated by DOE prior to completion in 1995. Prior to loss of funding from DOE, LLNL discovered that due to the large oxygen content in diesel exhaust, direct chemical reduction was not possible. In understanding why, a breakthrough was achieved that combined the use of a non-thermal plasma and a catalyst. This process was named Plasma Assisted Catalytic Reduction (P ACR). Because of this breakthrough, the CRADA became a funds-in only CRADA, once DOE DP funding ended. As a result, the funding decreased from about 1M dollars per year to about $400k per year. Subsequently, progress slowed as well. The CRADA was amended several times to reflect the funds-in nature. At each amendment, the deliverables were modified; the goals remained the same but the focus changed from heavy-duty to lightduty to SUVs. The diesel-engine NOx problem is similar to the furnace and boiler NOx emission problem with the added constraint that ammonia-like additives are impractical for a mobile source. Lean-burning gasoline engines are an additional area of application because the standard three-way catalyst is rendered ineffective by the presence of oxygen. In the P ACR process an electrical discharge is used to create a non-thermal plasma that contains oxidative radicals O and OH. These oxidative radicals convert NO to NO2. Selective catalytic

  11. Development of an X-Ray Catheter Final Report CRADA No. TC-1265-96

    Energy Technology Data Exchange (ETDEWEB)

    Trebes, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schlossberg, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-11-01

    Toe goal of this CRADA project was to develop a catheter-based x-ray source to provide treatment of restenosis in arteries with a radiation source which can be precisely controlled and turned on and off at will.

  12. Nano-Filament Field Emission Cathode Development Final Report CRADA No. TSB-0731-93

    Energy Technology Data Exchange (ETDEWEB)

    Bernhardt, Tony [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fahlen, Ted [Candescent Technologies Corporation, San Jose, CA (United States)

    2018-01-17

    At the time the CRADA was established, Silicon Video Corporation, of Cupertino, CA was a one-year-old rapidly growing start-up company. SVC was developing flat panel displays (FPDs) to replace Cathode Ray Terminals (CRTs) for personal computers, work stations and televisions. They planned to base their products on low cost and energy efficient field emission technology. It was universally recognized that the display was both the dominant cost item and differentiating feature of many products such as laptop computers and hand-held electronics and that control of the display technology through U.S. sources was essential to success in these markets. The purpose of this CRADA project was to determine if electrochemical planarization would be a viable, inexpensive alternative to current optical polishing techniques for planarizing the surface of a ceramic backplate of a thin film display.

  13. First Principles Diffusion Modeling Final Report CRADA No. TC-1540-98

    Energy Technology Data Exchange (ETDEWEB)

    delaRubia, T. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Foad, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Giles, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-10-19

    The CRADA participants built on the capabilities LLNL had already developed for ab initio diffusion modeling, extending them to higher doping and damage levels, and applying them to improve the understanding of implant and annealing tradeoffs for technology-relevant conditions. The calculation results and some of the simulation capabilities developed here were transferred to Intel and Applied Materials.

  14. Trinitromethyl Heterocyclic Oxidizers as a Solid Propellant Ingredient Final Report CRADA No TC02146.0

    Energy Technology Data Exchange (ETDEWEB)

    Pagoria, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Racoveanu, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-15

    This was a collaborative effort between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and Physical Sciences, Inc. (PSI), to develop a synthesis of two novel energetic heterocyclic oxidizers as possible replacements for ammonium perchlorate (AP) in rocket propellant formulations. This CRADA resulted from the award of the Phase I Small Business Technology Transfer (STTR) from DOD. The CRADA consisted of two phases. The goal for Phase 1 was to produce a new oxidizer called TNMDNP. Phase 2 is optional (based on the success of Phase 1) and the goal of Phase 2 (optional) was to produce a new oxidizer called TNMDNT. Phase 2 tasks would be performed based on the successful results of Phase 1.

  15. Electron Beam Curing of Polymer Matrix Composites - CRADA Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Janke, C. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howell, Dave [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Norris, Robert E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    1997-05-01

    The major cost driver in manufacturing polymer matrix composite (PMC) parts and structures, and one of the elements having the greatest effect on their quality and performance, is the standard thermal cure process. Thermal curing of PMCs requires long cure times and high energy consumption, creates residual thermal stresses in the part, produces volatile toxic by-products, and requires expensive tooling that is tolerant of the high cure temperatures.

  16. Mobile Ocean Test Berth Support: Cooperative Research and Development Final Report, CRADA Number CRD-10-413

    Energy Technology Data Exchange (ETDEWEB)

    LiVecchi, Albert [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-12-01

    The Northwest National Marine Renewable Energy Center (NNMREC), headquartered at the Oregon State University, is establishing the capabilities to test prototype wave energy conversion devices in the ocean. This CRADA will leverage the technical expertise and resources at NREL in the wind industry and in ocean engineering to support and enhance the development of the NNMREC Mobile Ocean Test Berth (MOTB). This CRADA will provide direct support to NNMREC by providing design evaluation and review of the MOTB, developing effective protocols for testing of the MOTB and wave energy conversion devices in the ocean, assisting in the specification of appropriate instrumentation and data acquisition packages, and providing guidance on obtaining and maintaining A2LA (American Association for Laboratory Accreditation) accreditation.

  17. Data summary report for M.W. Kellogg Z-sorb sorbent tests. CRADA 92-008 Final report

    Energy Technology Data Exchange (ETDEWEB)

    Everett, C E; Monaco, S J

    1994-05-01

    A series of tests were undertaken from August 6, 1992 through July 6, 1993 at METC`s High Pressure Bench-Scale Hot Gas Desulfurization Unit to support a Cooperative Research and Development Agreement (CRADA) between METC`s Sorbent Development Cluster and M.W. Kellogg. The M.W. Kellogg Company is currently developing a commercial offering of a hot gas clean-up system to be used in Integrated Gasification Combined Cycle (IGCC) systems. The intent of the CRADA agreement was to identify a suitable zinc-based desulfurization sorbent for the Sierra Pacific Power Company Clean Coal Technology Project, to identify optimum operating conditions for the sorbent, and to estimate potential sorbent loss per year. This report presents results pertaining to Phillips Petroleum`s Z-Sorb III sorbent.

  18. Complex Multi-Chamber Airbag Performance Simulation Final Report CRADA No. TSB-961-94

    Energy Technology Data Exchange (ETDEWEB)

    Kay, Gregory [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kithil, Philip [Advanced Safety Concepts, Inc. (ASCI), Santa Fe, NM (United States)

    2018-01-22

    The purpose of this small business CRADA was to evaluate the performance of new airbag concepts which were developed by the Advanced Safety Concepts, Inc. (ASCI). These new airbag concepts, if successful, could have major potential savings to society in terms of fewer injuries, lost time and lives.

  19. 78 FR 42532 - Cooperative Research and Development Agreement (CRADA) Opportunity With the Department of...

    Science.gov (United States)

    2013-07-16

    ... DEPARTMENT OF HOMELAND SECURITY Cooperative Research and Development Agreement (CRADA) Opportunity With the Department of Homeland Security for the Development of a Foot-and-Mouth Disease 3ABC ELISA Diagnostic Kit; Correction AGENCY: Science and Technology Directorate, Plum Island Animal Disease Center...

  20. Non-Invasive Pneumothorax Detector Final Report CRADA No. TC02110.0

    Energy Technology Data Exchange (ETDEWEB)

    Chang, J. T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Purcell, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-29

    This was a collaborative effort between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and ElectroSonics Medical Inc. (formerly known as BIOMEC, Inc.), to develop a non-invasive pneumothorax detector based upon the micropower impulse radar technology invented at LLNL. Under a Work for Others Subcontract (L-9248), LLNL and ElectroSonics successfully demonstrated the feasibility of a novel device for non-invasive detection of pneumothorax for emergency and long-term monitoring. The device is based on Micropower Impulse Radar (MIR) Ultra Wideband (UWB) technology. Phase I experimental results were promising, showing that a pneumothorax volume even as small as 30 ml was clearly detectable from the MIR signals. Phase I results contributed to the award of a National Institute of Health (NIH) SBIR Phase II grant to support further research and development. The Phase II award led to the establishment of a LLNL/ElectroSonics CRADA related to Case No. TC02045.0. Under the subsequent CRADA, LLNL and ElectroSonics successfully demonstrated the feasibility of the pneumothorax detection in human subject research trials. Under this current CRADA TC02110.0, also referred to as Phase II Type II, the project scope consisted of seven tasks in Project Year 1; five tasks in Project Year 2; and four tasks in Project Year 3. Year 1 tasks were aimed toward the delivery of the pneumothorax detector design package for the pre-production of the miniaturized CompactFlash dockable version of the system. The tasks in Project Years 2 and 3 critically depended upon the accomplishments of Task 1. Since LLNL’s task was to provide subject matter expertise and performance verification, much of the timeline of engagement by the LLNL staff depended upon the overall project milestones as determined by the lead organization ElectroSonics. The scope of efforts were subsequently adjusted accordingly to commensurate with funding

  1. 78 FR 71632 - Cooperative Research and Development Agreement (CRADA) Opportunity With the Department of...

    Science.gov (United States)

    2013-11-29

    ... processes leading to efficiencies while also saving money over time than employing single-use ISO bolts... automate processes leading to efficiencies and cost savings. Cross-border Commerce: Conveyance security... CRADA does not imply the future purchase of any materials, equipment, or services from the collaborating...

  2. Development of a Multi-Sensor Cancer Detection Probe Final Report CRADA No. TC-2026-01

    Energy Technology Data Exchange (ETDEWEB)

    Marion, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hular, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-10-16

    This collaboration continued work started under a previous CRADA (TSB-2023-00) to take a detailed concept specification for a multi-sensor needle/probe suitable for breast cancer analysis and produce a prototype system suitable for human FDA trials.

  3. CRADA Final Report for CRADA Number NFE-10-02991 "Development and Commercialization of Alternative Carbon Precursors and Conversion Technologies"

    Energy Technology Data Exchange (ETDEWEB)

    Norris, Rober [ORNL; Paulauskas, Felix [ORNL; Naskar, Amit [ORNL; Kaufman, Michael [ORNL; Yarborough, Ken [ORNL; Derstine, Chris [The Dow Chemical Company

    2013-10-01

    The overall objective of the collaborative research performed by the Oak Ridge National Laboratory (ORNL) and the Dow Chemical Company under this Cooperative Research And Development Agreement (CRADA NFE-10-02991) was to develop and establish pathways to commercialize new carbon fiber precursor and conversion technology. This technology is to produce alternative polymer fiber precursor formulations as well as scaled energy-efficient advanced conversion technology to enable continuous mode conversion to obtain carbonized fibers that are technically and economically viable in industrial markets such as transportation, wind energy, infrastructure and oil drilling applications. There have been efforts in the past to produce a low cost carbon fiber. These attempts have to be interpreted against the backdrop of the market needs at the time, which were strictly military aircraft and high-end aerospace components. In fact, manufacturing costs have been reduced from those days to current practice, where both process optimization and volume production have enabled carbon fiber to become available at prices below $20/lb. However, the requirements of the lucrative aerospace market limits further price reductions from current practice. This approach is different because specific industrial applications are targeted, most specifically wind turbine blade and light vehicle transportation, where aircraft grade carbon fiber is not required. As a result, researchers are free to adjust both manufacturing process and precursor chemistry to meet the relaxed physical specifications at a lower cost. This report documents the approach and findings of this cooperative research in alternative precursors and advanced conversion for production of cost-effective carbon fiber for energy missions. Due to export control, proprietary restrictions, and CRADA protected data considerations, specific design details and processing parameters are not included in this report.

  4. Advanced BorobondTM Shields for Nuclear Materials Containment and BorobondTM Immobilization of Volatile Fission Products - Final CRADA Report

    International Nuclear Information System (INIS)

    Wagh, Arun S.

    2016-01-01

    Borobond is a company-proprietary material developed by the CRADA partner in collaboration with Argonne, and is based on Argonne's Ceramicrete technology. It is being used by DOE for nuclear materials safe storage, and Boron Products, LLC is the manufacturer and supplier of Borobond. The major objective of this project was to produce a more versatile composition of this material and find new applications. Major target applications were use for nuclear radiation shields, such as in dry storage casks; use in immobilization of most difficult waste streams, such as Hanford K-Basin waste; use for soluble and volatile fission products, such as Cs, Tc, Sr, and I; and use for corrosion and fire protection applications in nuclear facilities.

  5. EnergyPlus Hysteresis PCM Model: Cooperative Research and Development Final Report, CRADA Number CRD-16-639

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Edwin S. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2018-02-22

    Under the CRADA, NREL will provide assistance to NRGsim to debug and convert the EnergyPlus Hysteresis Phase Change Material ('PCM') model to C++ for adoption into the main code package of the EnergyPlus simulation engine.

  6. CRADA Final Report for CRADA Number ORNL00-0605: Advanced Engine/Aftertreatment System R&D

    Energy Technology Data Exchange (ETDEWEB)

    Pihl, Josh A [ORNL; West, Brian H [ORNL; Toops, Todd J [ORNL; Adelman, Brad [Navistar; Derybowski, Edward [Navistar

    2011-10-01

    Navistar and ORNL established this CRADA to develop diesel engine aftertreatment configurations and control strategies that could meet emissions regulations while maintaining or improving vehicle efficiency. The early years of the project focused on reducing the fuel penalty associated with lean NOx trap (LNT), also known as NOx adsorber catalyst regeneration and desulfation. While Navistar pursued engine-based (in-cylinder) approaches to LNT regeneration, complementary experiments at ORNL focused on in-exhaust fuel injection. ORNL developed a PC-based controller for transient electronic control of EGR valve position, intake throttle position, and actuation of fuel injectors in the exhaust system of a Navistar engine installed at Oak Ridge. Aftertreatment systems consisting of different diesel oxidation catalysts (DOCs) in conjunction with a diesel particle filter and LNT were evaluated under quasi-steady-state conditions. Hydrocarbon (HC) species were measured at multiple locations in the exhaust system with Gas chromatograph mass spectrometry (GC-MS) and Fourier transform infrared (FTIR) spectroscopy. Under full-load, rated speed conditions, injection of fuel upstream of the DOC reduced the fuel penalty for a given level of NOx reduction by 10-20%. GC-MS showed that fuel compounds were 'cracked' into smaller hydrocarbon species over the DOC, particularly light alkenes. GC-MS analysis of HC species entering and exiting the LNT showed high utilization of light alkenes, followed by mono-aromatics; branched alkanes passed through the LNT largely unreacted. Follow-on experiments at a 'road load' condition were conducted, revealing that the NOx reduction was better without the DOC at lower temperatures. The improved performance was attributed to the large swings in the NOx adsorber core temperature. Split-injection experiments were conducted with ultra-low sulfur diesel fuel and three pure HC compounds: 1-pentene, toluene, and iso-octane. The pure

  7. Advanced Analog Signal Processing for Fuzing Final Report CRADA No. TC-1306-96

    Energy Technology Data Exchange (ETDEWEB)

    Fu, C. Y. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Spencer, D. [Raymond Engineering, Middletown, CT (United States)

    2018-01-24

    The purpose of this CRADA between LLNL and Kaman Aerospace/Raymond Engineering Operations (Raymond) was to demonstrate the feasibility of using Analog/Digital Neural Network (ANN) Technology for advanced signal processing, fuzing, and other applications. This cooperation sought to Ieverage the expertise and capabilities of both parties--Raymond to develop the signature recognition hardware system, using Raymond’s extensive experience in the area of system development plus Raymond’s knowledge of military applications, and LLNL to apply ANN and related technologies to an area of significant interest to the United States government. This CRADA effort was anticipated to be a three-year project consisting of three phases: Phase I, Proof-of-Principle Demonstration; Phase II, Proof-of-Design, involving the development of a form-factored integrated sensor and ANN technology processo~ and Phase III, Final Design and Release of the integrated sensor and ANN fabrication process: Under Phase I, to be conducted during calendar year 1996, Raymond was to deliver to LLNL an architecture (design) for an ANN chip. LLNL was to translate the design into a stepper mask and to produce and test a prototype chip from the Raymond design.

  8. Combustible structural composites and methods of forming combustible structural composites

    Science.gov (United States)

    Daniels, Michael A.; Heaps, Ronald J.; Steffler, Eric D.; Swank, W. David

    2013-04-02

    Combustible structural composites and methods of forming same are disclosed. In an embodiment, a combustible structural composite includes combustible material comprising a fuel metal and a metal oxide. The fuel metal is present in the combustible material at a weight ratio from 1:9 to 1:1 of the fuel metal to the metal oxide. The fuel metal and the metal oxide are capable of exothermically reacting upon application of energy at or above a threshold value to support self-sustaining combustion of the combustible material within the combustible structural composite. Structural-reinforcing fibers are present in the composite at a weight ratio from 1:20 to 10:1 of the structural-reinforcing fibers to the combustible material. Other embodiments and aspects are disclosed.

  9. CRADA/NFE-15-05779 Report: Fabrication of Large Area Printable Composite Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Paranthaman, M Parans [ORNL

    2016-09-29

    The technical objective of this technical collaboration phase I proposal was to fabricate large area NdFeB composite magnets at the Oak Ridge National Laboratory Manufacturing Demonstration Facility (ORNL MDF). The goal was to distribute domestically produced isotropic and highly anisotropic high energy density magnetic particles throughout the composite structure in order to enable site specific placement of magnetic phases and minimize the generated waste associated with permanent magnet manufacturing. Big area additive manufacturing (BAAM) and magnet composite fabrication methods were used in this study. BAAM was used to fabricate 65 vol % isotropic MQP NdFeB magnets in nylon polymer matrix. BAAM magnet cylinder was sliced to two magnetic arc-shaped braces. The density of the small BAAM magnet pieces reached 4.1 g/cm3, and the room temperature magnetic properties are: Intrinsic coercivity Hci = 8.8 kOe, Remanence Br = 4.2 kG, and energy product (BH)max = 3.7 MGOe. Also, 1.5” x 1.5” composite magnets with anisotropic MQA NdFeB magnet in a resin were also fabricated under magnetic field. The unaligned sample had a density of 3.75 g/cm3. However, aligned sample possessed a density of 4.27 g/cm3. The magnetic properties didn’t degrade during this process. This study provides a pathway for preparing composite magnets for various magnetic applications.

  10. Development of YBCO Superconductor for Electric Systems: Cooperative Research and Development Final Report, CRADA Number CRD-04-150

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, R.

    2013-03-01

    The proposed project will be collaborative in exploration of high temperature superconductor oxide films between SuperPower, Inc. and the National Renewable Energy Laboratory. This CRADA will attempt to develop YBCO based high temperature oxide technology.

  11. Electrical Resistance Tomography for Subsurface Imaging Final Report CRADA No. TC-609-93

    Energy Technology Data Exchange (ETDEWEB)

    Daily, William [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mondt, William [RIMtech, Inc., Westminster, CO (United States)

    2018-01-22

    The purpose of this CRADA was to develop a useful and commercially viable version of ERT technology for use in the oil, mining, engineering, and geotechnical industries. The goals required to accomplish these tasks included (1) developing commercial-grade data-acquisition systems and data analysis software, and (2) completing transfer of the state-of-the-art know-how, held by LLNL scientists and engineers, to personnel at RIMtech, Inc.

  12. Laser Shot Peening System Final Report CRADA No. TC-1369-96

    Energy Technology Data Exchange (ETDEWEB)

    Stuart, B. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Harris, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-27

    This CRADA project was established with a primary goal to develop a laser shot peening system which could operate at production throughput rates and produce the desired depth and intensity of induced shots. The first objective was to understand all parameters required for acceptable peening, including pulse energy, pulse temporal format, pulse spatial format, sample configuration and tamping mechanism. The next objective was to demonstrate the technique on representative samples and then on representative parts. The final objective was to implement the technology into a meaningful industrial peen.

  13. Development of a Laser for Landmine Destruction Final Report CRADA No. TC02126.0

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sheppard, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-31

    This was one of two CRADAs between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and First Alliance Technologies, LLC (First Alliance), to conduct research and development activity toward an integrated system for the detecting, locating, and destroying of landmines and unexploded ordinance using a laser to destroy landmines and unexploded ordinance and First Alliance’s Land Mine Locator (LML) system.

  14. Implementation of New Process Models for Tailored Polymer Composite Structures into Processing Software Packages

    International Nuclear Information System (INIS)

    Nguyen, Ba Nghiep; Jin, Xiaoshi; Wang, Jin; Phelps, Jay; Tucker, Charles L. III; Kunc, Vlastimil; Bapanapalli, Satish K.; Smith, Mark T.

    2010-01-01

    This report describes the work conducted under the Cooperative Research and Development Agreement (CRADA) (Nr. 260) between the Pacific Northwest National Laboratory (PNNL) and Autodesk, Inc. to develop and implement process models for injection-molded long-fiber thermoplastics (LFTs) in processing software packages. The structure of this report is organized as follows. After the Introduction Section (Section 1), Section 2 summarizes the current fiber orientation models developed for injection-molded short-fiber thermoplastics (SFTs). Section 3 provides an assessment of these models to determine their capabilities and limitations, and the developments needed for injection-molded LFTs. Section 4 then focuses on the development of a new fiber orientation model for LFTs. This model is termed the anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model as it explores the concept of anisotropic rotary diffusion to capture the fiber-fiber interaction in long-fiber suspensions and uses the reduced strain closure method of Wang et al. to slow down the orientation kinetics in concentrated suspensions. In contrast to fiber orientation modeling, before this project, no standard model was developed to predict the fiber length distribution in molded fiber composites. Section 5 is therefore devoted to the development of a fiber length attrition model in the mold. Sections 6 and 7 address the implementations of the models in AMI, and the conclusions drawn from this work is presented in Section 8.

  15. Improved Advanced Actuated Hybrid Mirrors Final Report CRADA No. TC02130.0

    Energy Technology Data Exchange (ETDEWEB)

    Barbee, T. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ealey, M. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-25

    This was a collaborative effort to develop and demonstrate an improved Advanced Actuated Hybrid Mirrors (AAHM) for commercial or Government purposes. The AAHM consists of a nanolaminate film replicating a precision optical surface bonded to a Silicon Carbide (SiC) substrate with active figure control capability. The goal of this project was to further the development of specific AAHM technologies. The intent of the CRADA was to combine the expertise of LLNL and NG Xinetics in the manufacture and test of a very high quality AAHM, incorporating lessons learned from earlier joint efforts.

  16. Development of Personal Decontamination System Final Report CRADA No. TC-02078-04

    Energy Technology Data Exchange (ETDEWEB)

    Smith, W. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); O' Dell, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-27

    This was a collaborative effort between The Regents of the University of California, Lawrence Livermore National Laboratory (LLNL) and O’Dell Engineering, Ltd. (O’Dell) to develop an improved low-cost personal decontamination system for Toxic Industrial Chemicals (TICs) and chemical agents. The significant change to the project was that COTS (Commercial Off-the Shelf Components) were identified that performed as well, or better than, the proprietary materials created and tested as part of this CRADA. These COTS components were combined to create a new LPDS (low-cost personal decontamination system) that met all specifications.

  17. Critical parameters for electron beam curing of cationic epoxies and property comparison of electron beam cured cationic epoxies versus thermal cured resins and composites

    International Nuclear Information System (INIS)

    Janke, C.J.; Norris, R.E.; Yarborough, K.; Lopata, V.J.

    1997-01-01

    Electron beam curing of composites is a nonthermal, nonautoclave curing process offering the following advantages compared to conventional thermal curing: substantially reduced manufacturing costs and curing times; improvements in part quality and performance; reduced environmental and health concerns; and improvements in material handling. In 1994 a Cooperative Research and Development Agreement (CRADA), sponsored by the Department of Energy Defense Programs and 10 industrial partners, was established to advance electron beam curing of composites. The CRADA has successfully developed hundreds of new toughened and untoughened resins, offering unlimited formulation and processing flexibility. Several patent applications have been filed for this work. Composites made from these easily processable, low shrinkage material match the performance of thermal cured composites and exhibit: low void contents comparable to autoclave cured composites (less than 1%); superb low water absorption values in the same range as cyanate esters (less than 1%); glass transition temperatures rivaling those of polyimides (greater than 390 C); mechanical properties comparable to high performance, autoclave cured composites; and excellent property retention after cryogenic and thermal cycling. These materials have been used to manufacture many composite parts using various fabrication processes including hand lay-up, tow placement, filament winding, resin transfer molding and vacuum assisted resin transfer molding

  18. Optical Mode Converters Final Report CRADA No. TC-0838-94

    Energy Technology Data Exchange (ETDEWEB)

    Pocha, Michael D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Carey, Kent [Hewlett-Packard Company, Palo Alto, CA (United States). Agilent Technologies

    2017-11-09

    The information age was maturing, and photonics was emerging as a significant technology with important'national security and commercial implications at the time of the CRADA. This was largely due to the vast information carrying capacity of optical beams and the availability of cheap.and effective optical fiber waveguides to guide the light. However, a major limitation to the widespread deployment of photonic systems was the high-cost (in an economic and performance sense) associated with coupling optical power between optoelectronic waveguide devices or between a device and an optical fiber. The problem was critical in the case of single-mode waveguide devices. Mitigating these costs would be a significant and pervasive enabler of the technology for a wide variety of applications that would have crucial defense and economic impact. The partners worked together to develop optical mode size converters on silicon substrates. Silicon was chosen because of its compatibility with the required photolithographic and micromachining techniques. By choosing silicon, these techniques could enable the close coupling of high-speed, high density silicon electronic circuitry to efficient low-cost photonics. The efficient coupling of electronics and photonics technologies would be important for many information age technologies. The joint nature of this project was intended to allow HP to benefit from some unique LLNL capabilities, and LLNL would be in a position to learn from HP and enhance its value to fundamental DP missions. Although the CRADA began as a hardware development project to develop the mode converter, it evolved into a software development venture. LLNL and HP researchers examined literature, performed some preliminary calculations, and evaluated production trade-offs of several known techniques to determine the best candidates for an integrated system.

  19. Agreement Execution Process Study: CRADAs and NF-WFO Agreements and the Speed of Business

    Energy Technology Data Exchange (ETDEWEB)

    Harrer, Bruce J.; Cejka, Cheryl L.; Macklin, Richard; Miksovic, Ann

    2011-02-01

    This report summarizes the findings of a study on the execution of Cooperative Research and Development Agreements (CRADAs) and Non-Federal Work for Others (NF-WFO) agreements across the U.S. Department of Energy (DOE) laboratory complex. The study provides quantitiative estimates of times required to negotiate and execute these agreements across the DOE complex. It identifies factors impacting on cycle times and describes best practicies used at various laboratories and site offices that reduce cycle times.

  20. Composite Structures Manufacturing Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Composite Structures Manufacturing Facility specializes in the design, analysis, fabrication and testing of advanced composite structures and materials for both...

  1. The Use of Vaporous Hydrogen Peroxide for Building Decontamination Final Report CRADA No. TC-2053-02

    Energy Technology Data Exchange (ETDEWEB)

    Verce, M. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schwartz, L. I. [Strategic Technology Enterprises, Inc., Mentor, OH (United States)

    2017-09-08

    This was a collaborative effort between LLNL and STE to investigate the use of vaporized hydrogen peroxide (VHP®) to decontaminate spore-contaminated heating, ventilation, and cooling (HV AC) systems in a trailer sized room. LLNL's effort under this CRADA was funded by DOE's Chemical and Biological National Security Program (CBNP), which later became part of Department of Homeland Security in 2004.

  2. High Temperature Catalytic Combustion Suppports Final Report CRADA No. TSB-0841-94

    Energy Technology Data Exchange (ETDEWEB)

    Hair, Lucy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Magno, Scott [Catalytic Combustion Systems, Inc., Mountain View, CA (United States)

    2018-01-19

    This Small Business CRADA between LLNL and Catalytica was executed on January 25, 1995. The total estimated cost of this project was 113K. LLNL's contribution was estimated at $50K funded under the DOE/Defense Program Small Business Initiative. Catalytica's in-kind contribution was estimated at 63K. Catalytic combusion catalyst systems operate at temperatures from 600°C to above 1300°C. Catalytica has developed technology that limits the catalyst temperature to below 1000°C. At temperatures in the range of 850 to 1000°C, the thermal stability of the catalyst is an important issue. Typical supports such as stabilized aluminas, hexaluminates, zirconia and stabilized zirconia supports are typically used but lack either thermal stability or other desirable properties. Catalytica had developed a new concept for thermally stable mixed oxide supports but this concept required the preparation of molecularly uniform precursors; that is, prior to high temperature treatment of these materials, the elements that make up the mixed oxide must be as nearly uniform as possible on a molecular level. The technique of sol gel processing appeared to be the preferred technique to make these molecularly uniform precursors, and a cooperative program with LLNL was established to prepare and test the proposed compounds. Catalytica proposed the composition and concentration levels for the materials to be prepared.

  3. Fiber Based Optical Amplifier for High Energy Laser Pulses Final Report CRADA No. TC02100.0

    Energy Technology Data Exchange (ETDEWEB)

    Messerly, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Cunningham, P. [Boeing Company, Springfield, VA (United States)

    2017-09-06

    This was a collaborative effort between Lawrence Livermore National Security, LLC (formerly The Regents of the University of California)/Lawrence Livermore National Laboratory (LLNL), and The Boeing Company to develop an optical fiber-based laser amplifier capable of producing and sustaining very high-energy, nanosecond-scale optical pulses. The overall technical objective of this CRADA was to research, design, and develop an optical fiber-based amplifier that would meet specific metrics.

  4. Recycling end-of-life vehicles of the future. Final CRADA report.

    Energy Technology Data Exchange (ETDEWEB)

    Jody, B. J.; Pomykala, J. A.; Spangenberger, J. S.; Daniels, E.; Energy Systems

    2010-01-14

    Argonne National Laboratory (the Contractor) entered into a Cooperative Research and Development Agreement (CRADA) with the following Participants: Vehicle Recycling Partnership, LLC (VRP, which consists of General Motors [GM], Ford, and Chrysler), and the American Chemistry Council - Plastics Division (ACC-PD). The purpose of this CRADA is to provide for the effective recycling of automotive materials. The long-term goals are to (1) enable the optimum recycling of automotive materials, thereby obviating the need for legislative mandates or directives; (2) enable the recovery of automotive materials in a cost-competitive manner while meeting the performance requirements of the applications and markets for the materials; and (3) remove recycling barriers/reasons, real or perceived, to the use of advanced lightweighting materials or systems in future vehicles. The issues, technical requirements, and cost and institutional considerations in achieving that goal are complex and will require a concerted, focused, and systematic analysis, together with a technology development program. The scope and tasks of this program are derived from 'A Roadmap for Recycling End-of-Life Vehicles of the Future,' prepared in May 2001 for the DOE Office of Energy, Efficiency, and Renewable Energy (EERE)-Vehicle Technologies Program. The objective of this research program is to enable the maximum recycling of automotive materials and obsolete vehicles through the development and commercialization of technologies for the separation and recovery of materials from end-of-life vehicles (ELVs). The long-term goals are to (1) enable the optimum recycling of automotive materials, thereby obviating the need for legislative mandates or directives; (2) enable the recovery of automotive materials in a cost-competitive manner while meeting the performance requirements of the applications and markets for the materials; and (3) remove recycling barriers/reasons, real or perceived, to the use

  5. Advanced composite structures. [metal matrix composites - structural design criteria for spacecraft construction materials

    Science.gov (United States)

    1974-01-01

    A monograph is presented which establishes structural design criteria and recommends practices to ensure the design of sound composite structures, including composite-reinforced metal structures. (It does not discuss design criteria for fiber-glass composites and such advanced composite materials as beryllium wire or sapphire whiskers in a matrix material.) Although the criteria were developed for aircraft applications, they are general enough to be applicable to space vehicles and missiles as well. The monograph covers four broad areas: (1) materials, (2) design, (3) fracture control, and (4) design verification. The materials portion deals with such subjects as material system design, material design levels, and material characterization. The design portion includes panel, shell, and joint design, applied loads, internal loads, design factors, reliability, and maintainability. Fracture control includes such items as stress concentrations, service-life philosophy, and the management plan for control of fracture-related aspects of structural design using composite materials. Design verification discusses ways to prove flightworthiness.

  6. Manufacturing and Characterization of Ultra Pure Ferrous Alloys Final Report CRADA No. TC02069.0

    Energy Technology Data Exchange (ETDEWEB)

    Lesuer, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McGreevy, T. E. [Caterpillar Inc., Mossville, IL (United States)

    2017-09-06

    This CRADA was a.collaborative effort between the Lawrence Livermore National Security LLC (formerly University of California)/Lawrence Livermore National Laboratory (LLNL),and Caterpillar Inc. (CaterpiHar), to further advance levitation casting techniques (developed at the Central Research Institute for Material (CRIM) in St. Petersburg, Russia) for use in manufacturing high purity metal alloys. This DOE Global Initiatives for Proliferation Prevention Program (IPP) project was to develop and demonstrate the levitation casting technology for producing ultra-pure alloys.

  7. The final technical report of the CRADA, 'Medical Accelerator Technology'

    International Nuclear Information System (INIS)

    Chu, W.T.; Rawls, J.M.

    2000-01-01

    Under this CRADA, Berkeley Lab and the industry partner, General Atomics (GA), have cooperatively developed hadron therapy technologies for commercialization. Specifically, Berkeley Lab and GA jointly developed beam transport systems to bring the extracted protons from the accelerator to the treatment rooms, rotating gantries to aim the treatment beams precisely into patients from any angle, and patient positioners to align the patient accurately relative to the treatment beams. We have also jointly developed a patient treatment delivery system that controls the radiation doses in the patient, and hardware to improve the accelerator performances, including a radio-frequency ion source and its low-energy beam transport (LEBT) system. This project facilitated the commercialization of the DOE-developed technologies in hadron therapy by the private sector in order to improve the quality of life of the nation

  8. Tire Development for Effective Transportation and Utilization of Used Tires, CRADA 01-N044, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Susan M. Maley

    2004-03-31

    Scrap tires represent a significant disposal and recycling challenge for the United States. Over 280 million tires are generated on an annual basis, and several states have large stockpiles or abandoned tire piles that are slated for remediation. While most states have programs to address the accumulation and generation of scrap tires, most of these states struggle with creating and sustaining recycling or beneficial end use markets. One of the major issues with market development has been the costs associated with transporting and processing the tires into material for recycling or disposal. According to a report by the Rubber Manufactures Association tire-derived fuel (TDF) represents the largest market for scrap tires, and approximately 115 million tires were consumed in 2001 as TDF (U.S. Scrap Tire Markets, 2001, December 2002, www.rma.org/scraptires). This market is supported primarily by cement kilns, followed by various industries including companies that operate utility and industrial boilers. However the use of TDF has not increased and the amount of TDF used by boiler operators has declined. The work completed through this cooperative research and development agreement (CRADA) has shown the potential of a mobile tire shredding unit to economically produce TDF and to provide an alterative low cost fuel to suitable coal-fired power systems. This novel system addresses the economic barriers by processing the tires at the retailer, thereby eliminating the costs associated with hauling whole tires. The equipment incorporated into the design allow for small 1-inch chunks of TDF to be produced in a timely fashion. The TDF can then be co-fired with coal in suitable combustion systems, such as a fluidized bed. Proper use of TDF has been shown to boost efficiency and reduce emissions from power generation systems, which is beneficial to coal utilization in existing power plants. Since the original scope of work outlined in the CRADA could not be completed because

  9. Hyperspectral Sensors Final Report CRADA No. TC02173.0

    Energy Technology Data Exchange (ETDEWEB)

    Priest, R. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sauvageau, J. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-30

    This was a collaborative effort between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and Science Applications International Corporation (SAIC), National Security Space Operations/SRBU, to develop longwave infrared (LWIR) hyperspectral imaging (HSI) sensors for airborne and potentially ground and space, platforms. LLNL has designed and developed LWIR HSI sensors since 1995. The current generation of these sensors has applications to users within the U.S. Department of Defense and the Intelligence Community. User needs are for multiple copies provided by commercial industry. To gain the most benefit from the U.S. Government’s prior investments in LWIR HSI sensors developed at LLNL, transfer of technology and know-how from LLNL HSI experts to commercial industry was needed. The overarching purpose of the CRADA project was to facilitate the transfer of the necessary technology from LLNL to SAIC thereby allowing the U.S. Government to procure LWIR HSI sensors from this company.

  10. High Resolution Sub-MM Fiberoptic Endoscope Final Report CRADA No. TSB-1447-97

    Energy Technology Data Exchange (ETDEWEB)

    Stone, Gary F. [Univ. of California, Livermore, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Smith, John [CML Fiberoptics, Inc., Auburn, NY (United States)

    2018-01-22

    At the time of the CRADA, LLNL needed to develop a sub-mm outer diameter fiberoptic endoscope with 25pm or better resolution at 3-lOmm working distance to support the Enhanced Surveillance Program (ESP) and the Core Surveillance Program for DOE. The commercially available systems did not meet the image resolution requirements and development work was needed to reach three goals. We also needed to perform preliminary investigations into the production of such an endoscope with a steerable-articulated distal end. The goal of such an endoscope was to allow for a 45 degree inspection cone including the lens field of view.

  11. Radiation curable adhesive compositions and composite structures

    International Nuclear Information System (INIS)

    Brenner, W.

    1984-01-01

    This disclosure relates to novel adhesive compositions and composite structures utilizing the same, wherein said adhesive compositions contain an elastomer, a chemically compatible ethylenically unsaturated monomer, a tackifier, an adhesion promoter, and optionally, pigments, fillers, thickeners and flow control agents which are converted from the liquid to the solid state by exposure to high energy ionizing radiation such as electron beam. A particularly useful application for such adhesive compositions comprises the assembly of certain composite structures or laminates consisting of, for example, a fiber flocked rubber sheet and a metal base with the adhesive fulfilling the multiple functions of adhering the flocked fiber to the rubber sheet as well as adhering the rubber sheet to the metal base. Optionally, the rubber sheet itself may also be cured at the same time as the adhesive composition with all operations being carried out at ambient temperatures and in the presence of air, with exposure of said assembly to selected dosages of high energy ionizing radiation. These adhesive compositions contain no solvents thereby almost eliminating air pollution or solvent toxicity problems, and offer substantial savings in energy and labor as they are capable of curing in very short time periods without the use of external heat which might damage the substrate

  12. Phase I ResonantSonic CRADA report

    International Nuclear Information System (INIS)

    Richterich, L.R.; Amos, L.O.; Fancher, J.D.; McLellan, G.W.; Setzer, W.V.; Tuttle, B.G.; Hockey, R.L.; Ferris, R.H.; Riechers, D.M.; Pitman, S.G.

    1994-01-01

    This test report describes the Phase 1 testing and results of the ResonantSonic drilling method. This effort was conducted as part of a Cooperative Research and Development Agreement (CRADA) between the US Department of Energy, Pacific Northwest Laboratory, Westinghouse Hanford Company and Water Development Corporation. The purpose of this demonstration was to evaluate the Water Development Corporation's ResonantSonic drilling system, modify components as necessary and determine compatible drilling applications for the ResonantSonic drilling method for use at facilities in the DOE complex and private industry. Initially, the ResonantSonic drill was used to drill several test holes at the Drilling Technology Test Site to assess the feasibility of drilling vertical and angle holes. After this initial phase, a 45 degree angle vapor extraction well was drilled to a depth of 168 feet at the 200 West Carbon Tetrachloride Site. This well was drilled and completed in nine days. Extensive geologic and vapor sampling were conducted while drilling this well. In addition, testing was also conducted at the test site to evaluated drilling with larger diameter casing (8 5/8 inch). Evaluation of the Resonant Sonic drilling method will be continued during the Phase 2 portion of testing to determine if improvements to the ResonantSonic system will make it a more viable method for drilling and sampling

  13. Composite Dry Structure Cost Improvement Approach

    Science.gov (United States)

    Nettles, Alan; Nettles, Mindy

    2015-01-01

    This effort demonstrates that by focusing only on properties of relevance, composite interstage and shroud structures can be placed on the Space Launch System vehicle that simultaneously reduces cost, improves reliability, and maximizes performance, thus providing the Advanced Development Group with a new methodology of how to utilize composites to reduce weight for composite structures on launch vehicles. Interstage and shroud structures were chosen since both of these structures are simple in configuration and do not experience extreme environments (such as cryogenic or hot gas temperatures) and should represent a good starting point for flying composites on a 'man-rated' vehicle. They are used as an example only. The project involves using polymer matrix composites for launch vehicle structures, and the logic and rationale behind the proposed new methodology.

  14. Structural Health Monitoring: Numerical Damage Predictor for Composite Structures

    National Research Council Canada - National Science Library

    Lannamann, Daniel

    2001-01-01

    .... Wide use of composites is found in aircraft, armored vehicles, ships and civil structures This present research demonstrates the ability to numerically detect damage in a composite sandwich structure...

  15. Development of improved x-ray optics for analytical x-ray microbeams. CRADA final report for CRADA Number Y-1294-0283

    International Nuclear Information System (INIS)

    Carpenter, D.A.; Gao, N.; Xiao, Q.F.; Ponomarev, I.

    1996-01-01

    The purpose of this CRADA was to develop improved glass capillary, x-ray optics for analytical x-ray microbeam applications. X-Ray Optical Systems, Inc. (XOS) designed and fabricated capillary optics and LMES tested those optics for x-ray microanalytical applications using its unique X-Ray Microprobe. Tapered capillaries with 3-microm and 8-microm output openings were fabricated and tested. The tapered capillaries had better spectral quality for x-ray microfluorescence (XRMF) analysis, than non-tapered, straight capillaries that are currently used in the system. X-ray beam count-rates for the tapered capillaries were also greater than the straight capillaries. Two monolithic, polycapillary optics were fabricated and tested. The polycapillary optics produced focal spots of 40 and 100 microm. Beam intensities for the polycapillaries were, respective, 44 and 18 times the intensities found in straight 50-microm and 100-microm capillaries. High-sensitivity scanning will be possible because of the enhanced intensity of the polycapillary optic. LMES and the DP program will benefit from improved capabilities for nondestructive x-ray microanalysis, while XOS will benefit from test results that will enhance the marketability of their products

  16. Carbon-carbon composites for orthopedic prosthesis and implants. CRADA final report

    Energy Technology Data Exchange (ETDEWEB)

    Burchell, T D; Klett, J W; Strizak, J P [Oak Ridge National Lab., TN (United States); Baker, C [FMI, Biddeford, ME (United States)

    1998-01-21

    The prosthetic implant market is extensive. For example, because of arthritic degeneration of hip and knee cartilage and osteoporotic fractures of the hip, over 200,000 total joint replacements (TJRs) are performed in the United States each year. Current TJR devices are typically metallic (stainless steel, cobalt, or titanium alloy) and are fixed in the bone with polymethylacrylate (PMMA) cement. Carbon-carbon composite materials offer several distinct advantages over metals for TJR prosthesis. Their mechanical properties can be tailored to match more closely the mechanical properties of human bone, and the composite may have up to 25% porosity, the size and distribution of which may be controlled through processing. The porous nature of carbon-carbon composites will allow for the ingrowth of bone, achieving biological fixation, and eliminating the need for PMMA cement fixation.

  17. Optimization of Laminated Composite Structures

    DEFF Research Database (Denmark)

    Henrichsen, Søren Randrup

    of the contributions of the PhD project are included in the second part of the thesis. Paper A presents a framework for free material optimization where commercially available finite element analysis software is used as analysis tool. Robust buckling optimization of laminated composite structures by including...... allows for a higher degree of tailoring of the resulting material. To enable better utilization of the composite materials, optimum design procedures can be used to assist the engineer. This PhD thesis is focused on developing numerical methods for optimization of laminated composite structures...... nonlinear analysis of structures, buckling and post-buckling analysis of structures, and formulations for optimization of structures considering stiffness, buckling, and post-buckling criteria. Lastly, descriptions, main findings, and conclusions of the papers are presented. The papers forming the basis...

  18. Laser Materials Processing Final Report CRADA No. TC-1526-98

    Energy Technology Data Exchange (ETDEWEB)

    Crane, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lehane, C. J. [United Technologies Corp., East Hartford, CT (United States)

    2017-09-08

    This CRADA project was a joint effort between Lawrence Livermore National Laboratory (LLNL) and United Technologies Corporation (UTC)/Pratt & Whitney (P&W) to demonstrate process capability for drilling holes in turbine airfoils using LLNL-developed femtosecond laser machining technology. The basis for this development was the ability of femtosecond lasers to drill precision holes in variety of materials with little or no collateral damage. The ultimate objective was to develop a laser machine tool consisting of an extremely advanced femtosecond laser subsystem to be developed by LLNL on a best-effort basis and a drilling station for turbine blades and vanes to be developed by P&W. In addition, P&W was responsible for commercializing the system. The goal of the so called Advanced Laser Drilling (ALD) system was to drill specified complex hole-shapes in turbine blades and vanes with a high degree precision and repeatability and simultaneously capable of very high speed processing.

  19. Adaptive, tolerant and efficient composite structures

    Energy Technology Data Exchange (ETDEWEB)

    Wiedemann, Martin; Sinapius, Michael (eds.) [German Aerospace Center DLR, Braunschweig (Germany). Inst. of Composite Structures and Adaptive Systems

    2013-07-01

    Polymer composites offer the possibility for functional integration since the material is produced simultaneously with the product. The efficiency of composite structures raises through functional integration. The specific production processes of composites offer the possibility to improve and to integrate more functions thus making the structure more valuable. Passive functions can be improved by combination of different materials from nano to macro scale, i.e. strength, toughness, bearing strength, compression after impact properties or production tolerances. Active functions can be realized by smart materials, i.e. morphing, active vibration control, active structure acoustic control or structure health monitoring. The basis is a comprehensive understanding of materials, simulation, design methods, production technologies and adaptronics. These disciplines together deliver advanced lightweight solutions for applications ranging from mechanical engineering to vehicles, airframe and space structures along the complete process chain. The book provides basics as well as inspiring ideas for engineers working in the field of adaptive, tolerant and robust composite structures.

  20. Forming of shape memory composite structures

    DEFF Research Database (Denmark)

    Santo, Loredana; Quadrini, Fabrizio; De Chiffre, Leonardo

    2013-01-01

    A new forming procedure was developed to produce shape memory composite structures having structural composite skins over a shape memory polymer core. Core material was obtained by solid state foaming of an epoxy polyester resin with remarkably shape memory properties. The composite skin consisted...... of a two-layer unidirectional thermoplastic composite (glass filled polypropylene). Skins were joined to the foamed core by hot compression without any adhesive: a very good adhesion was obtained as experimental tests confirmed. The structure of the foam core was investigated by means of computer axial...... tomography. Final shape memory composite panels were mechanically tested by three point bending before and after a shape memory step. This step consisted of a compression to reduce the panel thickness up to 60%. At the end of the bending test the panel shape was recovered by heating and a new memory step...

  1. Mechanical Model Development for Composite Structural Supercapacitors

    Science.gov (United States)

    Ricks, Trenton M.; Lacy, Thomas E., Jr.; Santiago, Diana; Bednarcyk, Brett A.

    2016-01-01

    Novel composite structural supercapacitor concepts have recently been developed as a means both to store electrical charge and to provide modest mechanical load carrying capability. Double-layer composite supercapacitors are often fabricated by impregnating a woven carbon fiber fabric, which serves as the electrodes, with a structural polymer electrolyte. Polypropylene or a glass fabric is often used as the separator material. Recent research has been primarily limited to evaluating these composites experimentally. In this study, mechanical models based on the Multiscale Generalized Method of Cells (MSGMC) were developed and used to calculate the shear and tensile properties and response of two composite structural supercapacitors from the literature. The modeling approach was first validated against traditional composite laminate data. MSGMC models for composite supercapacitors were developed, and accurate elastic shear/tensile properties were obtained. It is envisioned that further development of the models presented in this work will facilitate the design of composite components for aerospace and automotive applications and can be used to screen candidate constituent materials for inclusion in future composite structural supercapacitor concepts.

  2. Deformation Characteristics of Composite Structures

    Directory of Open Access Journals (Sweden)

    Theddeus T. AKANO

    2016-08-01

    Full Text Available The composites provide design flexibility because many of them can be moulded into complex shapes. The carbon fibre-reinforced epoxy composites exhibit excellent fatigue tolerance and high specific strength and stiffness which have led to numerous advanced applications ranging from the military and civil aircraft structures to the consumer products. However, the modelling of the beams undergoing the arbitrarily large displacements and rotations, but small strains, is a common problem in the application of these engineering composite systems. This paper presents a nonlinear finite element model which is able to estimate the deformations of the fibre-reinforced epoxy composite beams. The governing equations are based on the Euler-Bernoulli beam theory (EBBT with a von Kármán type of kinematic nonlinearity. The anisotropic elasticity is employed for the material model of the composite material. Moreover, the characterization of the mechanical properties of the composite material is achieved through a tensile test, while a simple laboratory experiment is used to validate the model. The results reveal that the composite fibre orientation, the type of applied load and boundary condition, affect the deformation characteristics of the composite structures. The nonlinearity is an important factor that should be taken into consideration in the analysis of the fibre-reinforced epoxy composites.

  3. Design and analysis of composite structures with applications to aerospace structures

    CERN Document Server

    Kassapoglou, Christos

    2010-01-01

    Design and Analysis of Composite Structures enables graduate students and engineers to generate meaningful and robust designs of complex composite structures. Combining analysis and design methods for structural components, the book begins with simple topics such as skins and stiffeners and progresses through to entire components of fuselages and wings. Starting with basic mathematical derivation followed by simplifications used in real-world design, Design and Analysis of Composite Structures presents the level of accuracy and range of applicability of each method. Examples taken from ac

  4. Adaptive, tolerant and efficient composite structures

    CERN Document Server

    Sinapius, Michael

    2013-01-01

    Polymer composites offer the possibility for functional integration since the material is produced simultaneously with the product. The efficiency of composite structures raises through functional integration. The specific production processes of composites offer the possibility to improve and to integrate more functions thus making the structure more valuable. Passive functions can be improved by combination of different materials from nano to macro scale, i.e. strength, toughness, bearing strength, compression after impact properties or production tolerances.  Active functions can be realized by smart materials, i.e. morphing, active vibration control, active structure acoustic control or structure health monitoring. The basis is a comprehensive understanding of materials, simulation, design methods, production technologies and adaptronics. These disciplines together deliver advanced lightweight solutions for applications ranging from mechanical engineering to vehicles, airframe and space structures along ...

  5. Advanced technology composite aircraft structures

    Science.gov (United States)

    Ilcewicz, Larry B.; Walker, Thomas H.

    1991-01-01

    Work performed during the 25th month on NAS1-18889, Advanced Technology Composite Aircraft Structures, is summarized. The main objective of this program is to develop an integrated technology and demonstrate a confidence level that permits the cost- and weight-effective use of advanced composite materials in primary structures of future aircraft with the emphasis on pressurized fuselages. The period from 1-31 May 1991 is covered.

  6. OCP TECD Report - TARDEC Blast Mitigation Program (BMP) and National Defense Industrial Association (NDIA) Michigan (MI) Chapter Cooperative Research and Development Agreement (CRADA) Summary

    Science.gov (United States)

    2017-09-26

    Standard, MIL-STD-3058, Occupant-Centric Protection for Military Ground Vehicles. 15. SUBJECT TERMS Occupant Centric Platform Technology-Enabled...Capability Demonstration (OCP TECD), Occupant-centric, Occupant Protection , Underbody Blast, National Defense Industrial Association (NDIA...Cooperative Research and Development Agreement (CRADA) 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF

  7. Structural biological composites: An overview

    Science.gov (United States)

    Meyers, Marc A.; Lin, Albert Y. M.; Seki, Yasuaki; Chen, Po-Yu; Kad, Bimal K.; Bodde, Sara

    2006-07-01

    Biological materials are complex composites that are hierarchically structured and multifunctional. Their mechanical properties are often outstanding, considering the weak constituents from which they are assembled. They are for the most part composed of brittle (often, mineral) and ductile (organic) components. These complex structures, which have risen from millions of years of evolution, are inspiring materials scientists in the design of novel materials. This paper discusses the overall design principles in biological structural composites and illustrates them for five examples; sea spicules, the abalone shell, the conch shell, the toucan and hornbill beaks, and the sheep crab exoskeleton.

  8. Proximity sensor system development. CRADA final report

    Energy Technology Data Exchange (ETDEWEB)

    Haley, D.C. [Oak Ridge National Lab., TN (United States); Pigoski, T.M. [Merrit Systems, Inc. (United States)

    1998-01-01

    Lockheed Martin Energy Research Corporation (LMERC) and Merritt Systems, Inc. (MSI) entered into a Cooperative Research and Development Agreement (CRADA) for the development and demonstration of a compact, modular proximity sensing system suitable for application to a wide class of manipulator systems operated in support of environmental restoration and waste management activities. In teleoperated modes, proximity sensing provides the manipulator operator continuous information regarding the proximity of the manipulator to objects in the workspace. In teleoperated and robotic modes, proximity sensing provides added safety through the implementation of active whole arm collision avoidance capabilities. Oak Ridge National Laboratory (ORNL), managed by LMERC for the United States Department of Energy (DOE), has developed an application specific integrated circuit (ASIC) design for the electronics required to support a modular whole arm proximity sensing system based on the use of capacitive sensors developed at Sandia National Laboratories. The use of ASIC technology greatly reduces the size of the electronics required to support the selected sensor types allowing deployment of many small sensor nodes over a large area of the manipulator surface to provide maximum sensor coverage. The ASIC design also provides a communication interface to support sensor commands from and sensor data transmission to a distributed processing system which allows modular implementation and operation of the sensor system. MSI is a commercial small business specializing in proximity sensing systems based upon infrared and acoustic sensors.

  9. Proximity sensor system development. CRADA final report

    International Nuclear Information System (INIS)

    Haley, D.C.; Pigoski, T.M.

    1998-01-01

    Lockheed Martin Energy Research Corporation (LMERC) and Merritt Systems, Inc. (MSI) entered into a Cooperative Research and Development Agreement (CRADA) for the development and demonstration of a compact, modular proximity sensing system suitable for application to a wide class of manipulator systems operated in support of environmental restoration and waste management activities. In teleoperated modes, proximity sensing provides the manipulator operator continuous information regarding the proximity of the manipulator to objects in the workspace. In teleoperated and robotic modes, proximity sensing provides added safety through the implementation of active whole arm collision avoidance capabilities. Oak Ridge National Laboratory (ORNL), managed by LMERC for the United States Department of Energy (DOE), has developed an application specific integrated circuit (ASIC) design for the electronics required to support a modular whole arm proximity sensing system based on the use of capacitive sensors developed at Sandia National Laboratories. The use of ASIC technology greatly reduces the size of the electronics required to support the selected sensor types allowing deployment of many small sensor nodes over a large area of the manipulator surface to provide maximum sensor coverage. The ASIC design also provides a communication interface to support sensor commands from and sensor data transmission to a distributed processing system which allows modular implementation and operation of the sensor system. MSI is a commercial small business specializing in proximity sensing systems based upon infrared and acoustic sensors

  10. Commercialization of Ultra-Hard Ceramics for Cutting Tools Final Report CRADA No. TC0279.0

    Energy Technology Data Exchange (ETDEWEB)

    Landingham, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Neumann, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-15

    This was a collaborative effort between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and Greenleaf Corporation (Greenleaf) to develop the technology for forming unique precursor nano-powders process that can be consolidated into ceramic products for industry. LLNL researchers have developed a solgel process for forming nano-ceramic powders. The nano powders are highly tailorable, allowing the explicit design of desired properties that lead to ultra hard materials with fine grain size. The present CRADA would allow the two parties to continue the development of the sol-gel process and the consolidation process in order to develop an industrially sound process for the manufacture of these ultra-hard materials.

  11. Flame-Resistant Composite Materials For Structural Members

    Science.gov (United States)

    Spears, Richard K.

    1995-01-01

    Matrix-fiber composite materials developed for structural members occasionally exposed to hot, corrosive gases. Integral ceramic fabric surface layer essential for resistance to flames and chemicals. Endures high temperature, impedes flame from penetrating to interior, inhibits diffusion of oxygen to interior where it degrades matrix resin, resists attack by chemicals, helps resist erosion, and provides additional strength. In original intended application, composite members replace steel structural members of rocket-launching structures that deteriorate under combined influences of atmosphere, spilled propellants, and rocket exhaust. Composites also attractive for other applications in which corrosion- and fire-resistant structural members needed.

  12. Thermomechanics of composite structures under high temperatures

    CERN Document Server

    Dimitrienko, Yu I

    2016-01-01

    This pioneering book presents new models for the thermomechanical behavior of composite materials and structures taking into account internal physico-chemical transformations such as thermodecomposition, sublimation and melting at high temperatures (up to 3000 K). It is of great importance for the design of new thermostable materials and for the investigation of reliability and fire safety of composite structures. It also supports the investigation of interaction of composites with laser irradiation and the design of heat-shield systems. Structural methods are presented for calculating the effective mechanical and thermal properties of matrices, fibres and unidirectional, reinforced by dispersed particles and textile composites, in terms of properties of their constituent phases. Useful calculation methods are developed for characteristics such as the rate of thermomechanical erosion of composites under high-speed flow and the heat deformation of composites with account of chemical shrinkage. The author expan...

  13. Composite materials for aircraft structures

    National Research Council Canada - National Science Library

    Baker, A. A; Dutton, Stuart; Kelly, Donald

    2004-01-01

    ... materials for aircraft structures / Alan Baker, Stuart Dutton, and Donald Kelly- 2nd ed. p. cm. - (Education series) Rev. ed. of: Composite materials for aircraft structures / edited by B. C. Hos...

  14. An evaluation of optical tool inspection and compensation technologies. CRADA final report for CRADA Number Y-1291-0052

    Energy Technology Data Exchange (ETDEWEB)

    Babelay, E.F. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States); Centola, J.; Zorger, W.; Serafin, W. [United Technologies, East Hartford, CT (United States). Pratt and Whitney Div.

    1994-05-15

    A Cooperative Research And Development Agreement (CRADA) was established April 1992 between Martin Marietta Energy Systems, Inc. and United Technologies Corporation, Pratt and Whitney Division to evaluate the existing applicability of the Energy Systems optical tool inspection and compensation system (OTICS) for use at Pratt and Whitney`s East Hartford Plant. The OTICS was developed at the Oak Ridge Y-12 Plant and optically measures the shape of a single point cutting tool. The tool shape inspection provides process information relating to tool wear and if desired the tool shape geometry can be used to generate a new numerical control machining program that is compensated for the tool forms errors. The tool wear measurement capability of OTICS was successfully evaluated in the Phase-1 testing. The testing verified that OTICS can easily detect tool wear and the {+-} 0.0001 inch resolution obtained was sufficient for the larger cutter inserts used by Pratt and Whitney (P and W). During the tool wear experiments at P and W, a second potential use identified for OTICS was the accurate on-machine dimensional verification of special ground contour forming tools. The OTICS tool path compensation experiment demonstrated the varied technologies that are integrated in the tool path compensation process. The OTICS system was successful at inspecting the 0.125 in. radius tool and compensating the tool path for tool form errors. The need for automated interfaces between the OTICS computer and controller along with the part program requirements and the overall compensation methodology were highlighted in the demonstration.

  15. Low Voltage Electron Beam Processing Final Report CRADA No. TC-645-93-A

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wakalopulos, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-10-16

    This CRADA project was established to develop a small, inexpensive sealed-tube electron beam processing system having immediate applications in industrial, high speed manufacturing processes, and in the Department of Energy (DOE) waste treatment/cleanup operations. The technical work involved the development and demonstration of a compact, sealed, 50-75 kilovolt (kV) EB generator prototype, including controls and power supply. The specific goals of this project were to develop a low cost vacuum tube capable of shooting an electron beam several inches into the air, and to demonstrate that wide area materials processing is feasible by stacking the tubes to produce continuous beams. During the project, we successfully demonstrated the producibility of a low cost electron beam system and several material processing operations of interest to US industry, DOE and, since September 11, 2001, the Homeland Security.

  16. Impact analysis of composite aircraft structures

    Science.gov (United States)

    Pifko, Allan B.; Kushner, Alan S.

    1993-01-01

    The impact analysis of composite aircraft structures is discussed. Topics discussed include: background remarks on aircraft crashworthiness; comments on modeling strategies for crashworthiness simulation; initial study of simulation of progressive failure of an aircraft component constructed of composite material; and research direction in composite characterization for impact analysis.

  17. Modeling Bistable Composite Laminates for Piezoelectric Morphing Structures

    OpenAIRE

    Darryl V. Murray; Oliver J. Myers

    2013-01-01

    A sequential modeling effort for bistable composite laminates for piezoelectric morphing structures is presented. Thin unsymmetric carbon fiber composite laminates are examined for use of morphing structures using piezoelectric actuation. When cooling from the elevated cure temperature to room temperature, these unsymmetric composite laminates will deform. These postcure room temperature deformation shapes can be used as morphing structures. Applying a force to these deformed laminates will c...

  18. Advanced composite structural concepts and material technologies for primary aircraft structures

    Science.gov (United States)

    Jackson, Anthony

    1991-01-01

    Structural weight savings using advanced composites have been demonstrated for many years. Most military aircraft today use these materials extensively and Europe has taken the lead in their use in commercial aircraft primary structures. A major inhibiter to the use of advanced composites in the United States is cost. Material costs are high and will remain high relative to aluminum. The key therefore lies in the significant reduction in fabrication and assembly costs. The largest cost in most structures today is assembly. As part of the NASA Advanced Composite Technology Program, Lockheed Aeronautical Systems Company has a contract to explore and develop advanced structural and manufacturing concepts using advanced composites for transport aircraft. Wing and fuselage concepts and related trade studies are discussed. These concepts are intended to lower cost and weight through the use of innovative material forms, processes, structural configurations and minimization of parts. The approach to the trade studies and the downselect to the primary wing and fuselage concepts is detailed. The expectations for the development of these concepts is reviewed.

  19. Quantitative NDE of Composite Structures at NASA

    Science.gov (United States)

    Cramer, K. Elliott; Leckey, Cara A. C.; Howell, Patricia A.; Johnston, Patrick H.; Burke, Eric R.; Zalameda, Joseph N.; Winfree, William P.; Seebo, Jeffery P.

    2015-01-01

    The use of composite materials continues to increase in the aerospace community due to the potential benefits of reduced weight, increased strength, and manufacturability. Ongoing work at NASA involves the use of the large-scale composite structures for spacecraft (payload shrouds, cryotanks, crew modules, etc). NASA is also working to enable the use and certification of composites in aircraft structures through the Advanced Composites Project (ACP). The rapid, in situ characterization of a wide range of the composite materials and structures has become a critical concern for the industry. In many applications it is necessary to monitor changes in these materials over a long time. The quantitative characterization of composite defects such as fiber waviness, reduced bond strength, delamination damage, and microcracking are of particular interest. The research approaches of NASA's Nondestructive Evaluation Sciences Branch include investigation of conventional, guided wave, and phase sensitive ultrasonic methods, infrared thermography and x-ray computed tomography techniques. The use of simulation tools for optimizing and developing these methods is also an active area of research. This paper will focus on current research activities related to large area NDE for rapidly characterizing aerospace composites.

  20. Development of Operational Free-Space-Optical (FSO) Laser Communication Systems Final Report CRADA No. TC02093.0

    Energy Technology Data Exchange (ETDEWEB)

    Ruggiero, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Orgren, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-15

    This project was a collaborative effort between Lawrence Livermore National Security, LLC (formerly The Regents of the University of California)/Lawrence Livermore National Laboratory (LLNL) and LGS Innovations, LLC (formerly Lucent Technologies, Inc.), to develop long-range and mobile operational free-space optical (FSO) laser communication systems for specialized government applications. LLNL and LGS Innovations formerly Lucent Bell Laboratories Government Communications Systems performed this work for a United States Government (USG) Intelligence Work for Others (I-WFO) customer, also referred to as "Government Customer", or "Customer" and "Government Sponsor." The CRADA was a critical and required part of the LLNL technology transfer plan for the customer.

  1. Uncertainty Quantification in Experimental Structural Dynamics Identification of Composite Material Structures

    DEFF Research Database (Denmark)

    Luczak, Marcin; Peeters, Bart; Kahsin, Maciej

    2014-01-01

    for uncertainty evaluation in experimentally estimated models. Investigated structures are plates, fuselage panels and helicopter main rotor blades as they represent different complexity levels ranging from coupon, through sub-component up to fully assembled structures made of composite materials. To evaluate......Aerospace and wind energy structures are extensively using components made of composite materials. Since these structures are subjected to dynamic environments with time-varying loading conditions, it is important to model their dynamic behavior and validate these models by means of vibration...

  2. Impact damages modeling in laminated composite structures

    Directory of Open Access Journals (Sweden)

    Kreculj Dragan D.

    2014-01-01

    Full Text Available Laminated composites have an important application in modern engineering structures. They are characterized by extraordinary properties, such as: high strength and stiffness and lightweight. Nevertheless, a serious obstacle to more widespread use of those materials is their sensitivity to the impact loads. Impacts cause initiation and development of certain types of damages. Failures that occur in laminated composite structures can be intralaminar and interlaminar. To date it was developed a lot of simulation models for impact damages analysis in laminates. Those models can replace real and expensive testing in laminated structures with a certain accuracy. By using specialized software the damage parameters and distributions can be determined (at certain conditions on laminate structures. With performing numerical simulation of impact on composite laminates there are corresponding results valid for the analysis of these structures.

  3. Durability of commercial aircraft and helicopter composite structures

    International Nuclear Information System (INIS)

    Dexter, H.B.

    1982-01-01

    The development of advanced composite technology during the past decade is discussed. Both secondary and primary components fabricated with boron, graphite, and Kevlar composites are evaluated. Included are spoilers, rudders, and fairings on commercial transports, boron/epoxy reinforced wing structure on C-130 military transports, and doors, fairings, tail rotors, vertical fins, and horizontal stabilizers on commercial helicopters. The development of composite structures resulted in advances in design and manufacturing technology for secondary and primary composite structures for commercial transports. Design concepts and inspection and maintenance results for the components in service are reported. The flight, outdoor ground, and controlled laboratory environmental effects on composites were also determined. Effects of moisture absorption, ultraviolet radiation, aircraft fuels and fluids, and sustained tensile stress are included. Critical parameters affecting the long term durability of composite materials are identified

  4. Durability of commercial aircraft and helicopter composite structures

    Science.gov (United States)

    Dexter, H. B.

    1982-01-01

    The development of advanced composite technology during the past decade is discussed. Both secondary and primary components fabricated with boron, graphite, and Kevlar composites are evaluated. Included are spoilers, rudders, and fairings on commercial transports, boron/epoxy reinforced wing structure on C-130 military transports, and doors, fairings, tail rotors, vertical fins, and horizontal stabilizers on commercial helicopters. The development of composite structures resulted in advances in design and manufacturing technology for secondary and primary composite structures for commercial transports. Design concepts and inspection and maintenance results for the components in service are reported. The flight, outdoor ground, and controlled laboratory environmental effects on composites were also determined. Effects of moisture absorption, ultraviolet radiation, aircraft fuels and fluids, and sustained tensile stress are included. Critical parameters affecting the long term durability of composite materials are identified.

  5. Advances in Computational Stability Analysis of Composite Aerospace Structures

    International Nuclear Information System (INIS)

    Degenhardt, R.; Araujo, F. C. de

    2010-01-01

    European aircraft industry demands for reduced development and operating costs. Structural weight reduction by exploitation of structural reserves in composite aerospace structures contributes to this aim, however, it requires accurate and experimentally validated stability analysis of real structures under realistic loading conditions. This paper presents different advances from the area of computational stability analysis of composite aerospace structures which contribute to that field. For stringer stiffened panels main results of the finished EU project COCOMAT are given. It investigated the exploitation of reserves in primary fibre composite fuselage structures through an accurate and reliable simulation of postbuckling and collapse. For unstiffened cylindrical composite shells a proposal for a new design method is presented.

  6. Anisotropic magnetism in field-structured composites

    International Nuclear Information System (INIS)

    Martin, James E.; Venturini, Eugene; Odinek, Judy; Anderson, Robert A.

    2000-01-01

    Magnetic field-structured composites (FSCs) are made by structuring magnetic particle suspensions in uniaxial or biaxial (e.g., rotating) magnetic fields, while polymerizing the suspending resin. A uniaxial field produces chainlike particle structures, and a biaxial field produces sheetlike particle structures. In either case, these anisotropic structures affect the measured magnetic hysteresis loops, with the magnetic remanence and susceptibility increased significantly along the axis of the structuring field, and decreased slightly orthogonal to the structuring field, relative to the unstructured particle composite. The coercivity is essentially unaffected by structuring. We present data for FSCs of magnetically soft particles, and demonstrate that the altered magnetism can be accounted for by considering the large local fields that occur in FSCs. FSCs of magnetically hard particles show unexpectedly large anisotropies in the remanence, and this is due to the local field effects in combination with the large crystalline anisotropy of this material. (c) 2000 The American Physical Society

  7. Wood-based composite materials : panel products, glued-laminated timber, structural composite lumber, and wood-nonwood composite materials

    Science.gov (United States)

    Nicole M. Stark; Zhiyong Cai; Charles Carll

    2010-01-01

    This chapter gives an overview of the general types and composition of wood-based composite products and the materials and processes used to manufacture them. It describes conventional wood-based composite panels and structural composite materials intended for general construction, interior use, or both. This chapter also describes wood–nonwood composites. Mechanical...

  8. Tooling Foam for Structural Composite Applications

    Science.gov (United States)

    DeLay, Tom; Smith, Brett H.; Ely, Kevin; MacArthur, Doug

    1998-01-01

    Tooling technology applications for composite structures fabrication have been expanded at MSFC's Productivity Enhancement Complex (PEC). Engineers from NASA/MSFC and Lockheed Martin Corporation have developed a tooling foam for use in composite materials processing and manufacturing that exhibits superior thermal and mechanical properties in comparison with other tooling foam materials. This tooling foam is also compatible with most preimpregnated composite resins such as epoxy, bismaleimide, phenolic and their associated cure cycles. MARCORE tooling foam has excellent processability for applications requiring either integral or removable tooling. It can also be tailored to meet the requirements for composite processing of parts with unlimited cross sectional area. A shelf life of at least six months is easily maintained when components are stored between 50F - 70F. The MARCORE tooling foam system is a two component urethane-modified polyisocyanurate, high density rigid foam with zero ozone depletion potential. This readily machineable, lightweight tooling foam is ideal for composite structures fabrication and is dimensionally stable at temperatures up to 350F and pressures of 100 psi.

  9. Structural evolution of chitosan–palygorskite composites and removal of aqueous lead by composite beads

    International Nuclear Information System (INIS)

    Rusmin, Ruhaida; Sarkar, Binoy; Liu, Yanju; McClure, Stuart; Naidu, Ravi

    2015-01-01

    Graphical abstract: - Highlights: • Facile preparation of chitosan–palygorskite composite beads demonstrated. • Components’ mass ratio impacted structural characteristics of composites. • Mechanism of composite formation and structure of composite beads proposed. • Composite beads adsorbed significantly greater amount of Pb than pristine materials. • In-depth investigation done on Pb adsorption mechanisms. - Abstract: This paper investigates the structural evolution of chitosan–palygorskite (CP) composites in relation to variable mass ratios of their individual components. The composite beads’ performance in lead (Pb) adsorption from aqueous solution was also examined. The composite beads were prepared through direct dispersion of chitosan and palygorskite at 1:1, 1:2 and 2:1 mass ratios (CP1, CP2 and C2P, respectively). Analyses by Fourier transform Infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the dependence of the composites’ structural characteristics on their composition mass ratio. The chitosan–palygorskite composite beads exhibited a better Pb adsorption performance than the pristine materials (201.5, 154.5, 147.1, 27.7 and 9.3 mg g"−"1 for CP1, C2P, CP2, chitosan and palygorskite, respectively). Adsorption of Pb by CP1 and CP2 followed Freundlich isothermal model, while C2P fitted to Langmuir model. Kinetic studies showed that adsorption by all the composites fitted to the pseudo-second order model with pore diffusion also acting as a major rate governing step. The surface properties and specific interaction between chitosan and palygorskite in the composites were the most critical factors that influenced their capabilities in removing toxic metals from water.

  10. Structural evolution of chitosan–palygorskite composites and removal of aqueous lead by composite beads

    Energy Technology Data Exchange (ETDEWEB)

    Rusmin, Ruhaida, E-mail: ruhaida.rusmin@mymail.unisa.edu.au [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); Faculty of Applied Sciences, Universiti Teknologi MARA Negeri Sembilan, Kuala Pilah 72000 (Malaysia); Sarkar, Binoy, E-mail: binoy.sarkar@unisa.edu.au [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); CRC CARE – Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, P.O. Box 486, Salisbury, SA 5106 (Australia); Liu, Yanju [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); CRC CARE – Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, P.O. Box 486, Salisbury, SA 5106 (Australia); McClure, Stuart [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); Naidu, Ravi, E-mail: Ravi.Naidu@newcastle.edu.au [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); CRC CARE – Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, P.O. Box 486, Salisbury, SA 5106 (Australia)

    2015-10-30

    Graphical abstract: - Highlights: • Facile preparation of chitosan–palygorskite composite beads demonstrated. • Components’ mass ratio impacted structural characteristics of composites. • Mechanism of composite formation and structure of composite beads proposed. • Composite beads adsorbed significantly greater amount of Pb than pristine materials. • In-depth investigation done on Pb adsorption mechanisms. - Abstract: This paper investigates the structural evolution of chitosan–palygorskite (CP) composites in relation to variable mass ratios of their individual components. The composite beads’ performance in lead (Pb) adsorption from aqueous solution was also examined. The composite beads were prepared through direct dispersion of chitosan and palygorskite at 1:1, 1:2 and 2:1 mass ratios (CP1, CP2 and C2P, respectively). Analyses by Fourier transform Infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the dependence of the composites’ structural characteristics on their composition mass ratio. The chitosan–palygorskite composite beads exhibited a better Pb adsorption performance than the pristine materials (201.5, 154.5, 147.1, 27.7 and 9.3 mg g{sup −1} for CP1, C2P, CP2, chitosan and palygorskite, respectively). Adsorption of Pb by CP1 and CP2 followed Freundlich isothermal model, while C2P fitted to Langmuir model. Kinetic studies showed that adsorption by all the composites fitted to the pseudo-second order model with pore diffusion also acting as a major rate governing step. The surface properties and specific interaction between chitosan and palygorskite in the composites were the most critical factors that influenced their capabilities in removing toxic metals from water.

  11. Structural modeling for multicell composite rotor blades

    Science.gov (United States)

    Rehfield, Lawrence W.; Atilgan, Ali R.

    1987-01-01

    Composite material systems are currently good candidates for aerospace structures, primarily for the design flexibility they offer, i.e., it is possible to tailor the material and manufacturing approach to the application. A working definition of elastic or structural tailoring is the use of structural concept, fiber orientation, ply stacking sequence, and a blend of materials to achieve specific performance goals. In the design process, choices of materials and dimensions are made which produce specific response characteristics, and which permit the selected goals to be achieved. Common choices for tailoring goals are preventing instabilities or vibration resonances or enhancing damage tolerance. An essential, enabling factor in the design of tailored composite structures is structural modeling that accurately, but simply, characterizes response. The objective of this paper is to present a new multicell beam model for composite rotor blades and to validate predictions based on the new model by comparison with a finite element simulation in three benchmark static load cases.

  12. Development of thermoplastic composite aircraft structures

    Science.gov (United States)

    Renieri, Michael P.; Burpo, Steven J.; Roundy, Lance M.; Todd, Stephanie A.; Kim, H. J.

    1992-01-01

    Efforts focused on the use of thermoplastic composite materials in the development of structural details associated with an advanced fighter fuselage section with applicability to transport design. In support of these designs, mechanics developments were conducted in two areas. First, a dissipative strain energy approach to material characterization and failure prediction, developed at the Naval Research Laboratory, was evaluated as a design/analysis tool. Second, a finite element formulation for thick composites was developed and incorporated into a lug analysis method which incorporates pin bending effects. Manufacturing concepts were developed for an upper fuel cell cover. A detailed trade study produced two promising concepts: fiber placement and single-step diaphragm forming. Based on the innovative design/manufacturing concepts for the fuselage section primary structure, elements were designed, fabricated, and structurally tested. These elements focused on key issues such as thick composite lugs and low cost forming of fastenerless, stiffener/moldine concepts. Manufacturing techniques included autoclave consolidation, single diaphragm consolidation (SDCC) and roll-forming.

  13. Combined use of polymer composites and metals in engineering structures

    International Nuclear Information System (INIS)

    Hoa, S.V.

    2002-01-01

    Polymer matrix composites have found many applications in the construction of light weight structures such as those in aircrafts, automobiles, sports equipment etc. This is because these materials possess high stiffness, high strength and low densities. In applications of polymer matrix composites in the light weight structures, the polymer composites are however, not used by themselves alone in most cases. Usually the polymer composites are used in conjunction with some metal components. The metal components are used either to provide means for joining the composite components or the composites are used to repair the cracked metal structures. The synergistic effect of both metals and composites can provide excellent performance with good economy. This paper presents a few applications where polymer composites are used in conjunction with metals in engineering structures. (author)

  14. Transition from glass to graphite in manufacture of composite aircraft structure

    Science.gov (United States)

    Buffum, H. E.; Thompson, V. S.

    1978-01-01

    The transition from fiberglass reinforced plastic composites to graphite reinforced plastic composites is described. Structural fiberglass design and manufacturing background are summarized. How this experience provides a technology base for moving into graphite composite secondary structure and then to composite primary structure is considered. The technical requirements that must be fulfilled in the transition from glass to graphite composite structure are also included.

  15. Structural Health Monitoring for Impact Damage in Composite Structures.

    Energy Technology Data Exchange (ETDEWEB)

    Roach, Dennis P.; Raymond Bond (Purdue); Doug Adams (Purdue)

    2014-08-01

    Composite structures are increasing in prevalence throughout the aerospace, wind, defense, and transportation industries, but the many advantages of these materials come with unique challenges, particularly in inspecting and repairing these structures. Because composites of- ten undergo sub-surface damage mechanisms which compromise the structure without a clear visual indication, inspection of these components is critical to safely deploying composite re- placements to traditionally metallic structures. Impact damage to composites presents one of the most signi fi cant challenges because the area which is vulnerable to impact damage is generally large and sometimes very dif fi cult to access. This work seeks to further evolve iden- ti fi cation technology by developing a system which can detect the impact load location and magnitude in real time, while giving an assessment of the con fi dence in that estimate. Fur- thermore, we identify ways by which impact damage could be more effectively identi fi ed by leveraging impact load identi fi cation information to better characterize damage. The impact load identi fi cation algorithm was applied to a commercial scale wind turbine blade, and results show the capability to detect impact magnitude and location using a single accelerometer, re- gardless of sensor location. A technique for better evaluating the uncertainty of the impact estimates was developed by quantifying how well the impact force estimate meets the assump- tions underlying the force estimation technique. This uncertainty quanti fi cation technique was found to reduce the 95% con fi dence interval by more than a factor of two for impact force estimates showing the least uncertainty, and widening the 95% con fi dence interval by a fac- tor of two for the most uncertain force estimates, avoiding the possibility of understating the uncertainty associated with these estimates. Linear vibration based damage detection tech- niques were investigated in the

  16. Composite materials for cryogenic structures

    International Nuclear Information System (INIS)

    Kasen, M.B.

    1978-01-01

    The paper is concerned with the composition, mechanical properties and capabilities of various types of composite materials for cryogenic structures. Attention is given to high-pressure plastic laminates, low-pressure plastic laminates, metal-matrix laminates, and aggregates (low-temperature concretes). The ability of these materials to match the strength and modulus of stainless steels suggests that their usage will substantially increase as alloying elements become scarce and more expensive

  17. In-service inspection guidelines for composite aerospace structures

    International Nuclear Information System (INIS)

    Heida, Jaap H.; Platenkamp, Derk J.

    2012-01-01

    The in-service inspection of composite aerospace structures is reviewed, using the results of a evaluation of promising, mobile non-destructive inspection (NDI) methods. The evaluation made use of carbon fibre reinforced specimens representative for primary composite aerospace structures, including relevant damage types such as impact damage, delaminations and disbonds. A range of NDI methods were evaluated such as visual inspection, vibration analysis, phased array ultrasonic inspection, shearography and thermography inspection. Important aspects of the evaluation were the capability for defect detection and characterization, portability of equipment, field of view, couplant requirements, speed of inspection, level of training required and the cost of equipment. The paper reviews the damage tolerance design approach for composites, and concludes with guidelines for the in-service inspection of composite aerospace structures.

  18. Hydrodynamic Forces on Composite Structures

    Science.gov (United States)

    2014-06-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited HYDRODYNAMIC ...Thesis 4. TITLE AND SUBTITLE HYDRODYNAMIC FORCES ON COMPOSITE STRUCTURES 5. FUNDING NUMBERS 6. AUTHOR(S) Scott C. Millhouse 7. PERFORMING...angles yields different free surface effects including vortices and the onset of cavitation . 14. SUBJECT TERMS Fluid structure interaction, FSI, finite

  19. Conversion of Indigenous Agricultural Waste Feedstocks to Fuel Ethanol. Cooperative Research and Development Final Report, CRADA Number CRD-13-504

    Energy Technology Data Exchange (ETDEWEB)

    Elander, Richard [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-03-27

    This Cooperative Research and Development Agreement (CRADA) is between the National Renewable Energy Laboratory (NREL), a world leader in biomass conversion research and Ecopetrol American Inc., Ecopetrol S.A.'s U.S. subsidiary. The research and development efforts described in the Joint Work Statement (JWS) will take advantage of the strengths of both parties. NREL will use its Integrated Biorefinery Facility and vast experience in the conversion of lignocellulosic feedstocks to fuel ethanol to develop processes for the conversion of Ecopetrol's feedstocks. Ecopetrol will establish the infrastructure in Columbia to commercialize the conversion process.

  20. Growth of large detector crystals. CRADA final report

    International Nuclear Information System (INIS)

    Boatner, L.A.; Samuelson, S.

    1997-01-01

    In the course of a collaborative research effort between L.A. Boatner of Oak Ridge National Laboratory and Prof. Alex Lempicki of the Department of Chemistry of Boston University, a new highly efficient and very fast scintillator for the detection of gamma-rays was discovered. This new scintillator consists of a single crystal of lutetium orthophosphate (LuPO 4 ) to which a small percentage of trivalent cerium is added as an activator ion. The new lutetium orthophosphate-cerium scintillator was found to be superior in performance to bismuth germanium oxide--a material that is currently widely used as a gamma-ray detector in a variety of medical, scientific, and technical applications. Single crystals of LuPO 4 and related rare-earth orthophosphates had been grown for a number of years in the ORNL Solid State Division prior to the discovery of the efficient gamma-ray-scintillation response of LuPO 4 :Ce. The high-temperature-solvent (flux-growth) method used for the growth of these crystals was capable of producing crystals in sizes that were adequate for research purposes but that were inadequate for commercial-scale production and widespread application. The CRADA between ORNL and Deltronic Crystal Industries of Dover, NJ was undertaken for the purpose of investigating alternate approaches, such as top-seeded-solution growth, to the growth of LuPO 4 :Ce scintillator crystals in sizes significantly larger than those obtainable through the application of standard flux-growth methods and, therefore, suitable for commercial sales and applications

  1. Deployable structures using bistable reeled composites

    Science.gov (United States)

    Daton-Lovett, Andrew J.; Compton-Bishop, Quentin M.; Curry, Richard G.

    2000-06-01

    This paper describes an innovative, patented use of composite materials developed by RolaTube Technology Ltd. to make smart deployable structures. Bi-stable reeled composites (BRCs) can alternate between two stable forms; that of a strong, rigid structure and that of a compact coil of flat-wound material. Bi-stability arises as a result of the manipulation of Poisson's ratio and isotropy in the various layers of the material. BRCs are made of fiber- reinforced composite materials, most often with a thermoplastic matrix. A range of fibers and polymer matrices can be used according to the requirements of the operating environment. Samples of a BRC structure were constructed using layers of unidirectional, fiber-reinforced thermoplastic sheet with the layers at different angles. The whole assembly was then consolidated under conditions of elevated temperature and pressure. The properties of the BRC are described and the result of a series of experiments performed on the sample to determine the tensile strength of the BRC structure are reported. A full analysis using finite element methods is being undertaken in collaboration with the University of Cambridge, England. The first commercial use has been to fabricate boom and drive mechanisms for the remote inspection of industrial plant.

  2. Assessment of Veritainer's Spreader-Bar-Mounted Radiation Detection Systems Final Report CRADA No. TC02150.0

    Energy Technology Data Exchange (ETDEWEB)

    Labov, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Alioto, J. I. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2012-05-29

    This was a collaborative effort between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and VeriTainer Corporation, to develop algorithms and testing of VeriTainer’s spreader-bar mounted radiation detection system, the VeriSpreader™. The goal of the project was to improve the VeriSpreader™ System to the point where it would meet or exceed "DOE Guidance" for radiation detection, in order to be deployed for commercial and government applications. The VeriSpreader™ had gone through several rounds of testing by DHS and DOE. NNSA had requested that VeriTainer engage in a CRADA with a national lab in order to further develop and test the VeriSpreader™ System.

  3. Commercial transport aircraft composite structures

    Science.gov (United States)

    Mccarty, J. E.

    1983-01-01

    The role that analysis plays in the development, production, and substantiation of aircraft structures is discussed. The types, elements, and applications of failure that are used and needed; the current application of analysis methods to commercial aircraft advanced composite structures, along with a projection of future needs; and some personal thoughts on analysis development goals and the elements of an approach to analysis development are discussed.

  4. Atrial Model Development and Prototype Simulations: CRADA Final Report on Tasks 3 and 4

    Energy Technology Data Exchange (ETDEWEB)

    O' Hara, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zhang, X. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Villongco, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lightstone, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Richards, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-28

    The goal of this CRADA was to develop essential tools needed to simulate human atrial electrophysiology in 3-dimensions using an anatomical image-based anatomy and physiologically detailed human cellular model. The atria were modeled as anisotropic, representing the preferentially longitudinal electrical coupling between myocytes. Across the entire anatomy, cellular electrophysiology was heterogeneous, with left and right atrial myocytes defined differently. Left and right cell types for the “control” case of sinus rhythm (SR) was compared with remodeled electrophysiology and calcium cycling characteristics of chronic atrial fibrillation (cAF). The effects of Isoproterenol (ISO), a beta-adrenergic agonist that represents the functional consequences of PKA phosphorylation of various ion channels and transporters, was also simulated in SR and cAF to represent atrial activity under physical or emotional stress. Results and findings from Tasks 3 & 4 are described. Tasks 3 and 4 are, respectively: Input parameters prepared for a Cardioid simulation; Report including recommendations for additional scenario development and post-processing analytic strategy.

  5. Buckling optimization of steering stiffeners for grid-stiffened composite structures

    NARCIS (Netherlands)

    Wang, D.; Abdalla, M.M.

    2015-01-01

    Grid-stiffened composite structures, where the skin is stiffened by a lattice of stiffeners, not only allow for significant reduction in structural weight but are also competitive in terms of structural stability and damage tolerance compared with sandwich composite structures. As the development of

  6. Ink composition for making a conductive silver structure

    Science.gov (United States)

    Walker, Steven B.; Lewis, Jennifer A.

    2016-10-18

    An ink composition for making a conductive silver structure comprises a silver salt and a complex of (a) a complexing agent and a short chain carboxylic acid or (b) a complexing agent and a salt of a short chain carboxylic acid, according to one embodiment. A method for making a silver structure entails combining a silver salt and a complexing agent, and then adding a short chain carboxylic acid or a salt of the short chain carboxylic acid to the combined silver salt and a complexing agent to form an ink composition. A concentration of the complexing agent in the ink composition is reduced to form a concentrated formulation, and the silver salt is reduced to form a conductive silver structure, where the concentrated formulation and the conductive silver structure are formed at a temperature of about 120.degree. C. or less.

  7. Dynamic Failure of Composite and Sandwich Structures

    CERN Document Server

    Abrate, Serge; Rajapakse, Yapa D S

    2013-01-01

    This book presents a broad view of the current state of the art regarding the dynamic response of composite and sandwich structures subjected to impacts and explosions. Each chapter combines a thorough assessment of the literature with original contributions made by the authors.  The first section deals with fluid-structure interactions in marine structures.  The first chapter focuses on hull slamming and particularly cases in which the deformation of the structure affects the motion of the fluid during the water entry of flexible hulls. Chapter 2 presents an extensive series of tests underwater and in the air to determine the effects of explosions on composite and sandwich structures.  Full-scale structures were subjected to significant explosive charges, and such results are extremely rare in the open literature.  Chapter 3 describes a simple geometrical theory of diffraction for describing the interaction of an underwater blast wave with submerged structures. The second section addresses the problem of...

  8. Progressive fracture of polymer matrix composite structures: A new approach

    Science.gov (United States)

    Chamis, C. C.; Murthy, P. L. N.; Minnetyan, L.

    1992-01-01

    A new approach independent of stress intensity factors and fracture toughness parameters has been developed and is described for the computational simulation of progressive fracture of polymer matrix composite structures. The damage stages are quantified based on physics via composite mechanics while the degradation of the structural behavior is quantified via the finite element method. The approach account for all types of composite behavior, structures, load conditions, and fracture processes starting from damage initiation, to unstable propagation and to global structural collapse. Results of structural fracture in composite beams, panels, plates, and shells are presented to demonstrate the effectiveness and versatility of this new approach. Parameters and guidelines are identified which can be used as criteria for structural fracture, inspection intervals, and retirement for cause. Generalization to structures made of monolithic metallic materials are outlined and lessons learned in undertaking the development of new approaches, in general, are summarized.

  9. Development of Textile Reinforced Composites for Aircraft Structures

    Science.gov (United States)

    Dexter, H. Benson

    1998-01-01

    NASA has been a leader in development of composite materials for aircraft applications during the past 25 years. In the early 1980's NASA and others conducted research to improve damage tolerance of composite structures through the use of toughened resins but these resins were not cost-effective. The aircraft industry wanted affordable, robust structures that could withstand the rigors of flight service with minimal damage. The cost and damage tolerance barriers of conventional laminated composites led NASA to focus on new concepts in composites which would incorporate the automated manufacturing methods of the textiles industry and which would incorporate through-the-thickness reinforcements. The NASA Advanced Composites Technology (ACT) Program provided the resources to extensively investigate the application of textile processes to next generation aircraft wing and fuselage structures. This paper discusses advanced textile material forms that have been developed, innovative machine concepts and key technology advancements required for future application of textile reinforced composites in commercial transport aircraft. Multiaxial warp knitting, triaxial braiding and through-the-thickness stitching are the three textile processes that have surfaced as the most promising for further development. Textile reinforced composite structural elements that have been developed in the NASA ACT Program are discussed. Included are braided fuselage frames and window-belt reinforcements, woven/stitched lower fuselage side panels, stitched multiaxial warp knit wing skins, and braided wing stiffeners. In addition, low-cost processing concepts such as resin transfer molding (RTM), resin film infusion (RFI), and vacuum-assisted resin transfer molding (VARTM) are discussed. Process modeling concepts to predict resin flow and cure in textile preforms are also discussed.

  10. Development of HANAA to Achieve Commercialization Final Report CRADA No. TC-2025-01

    Energy Technology Data Exchange (ETDEWEB)

    Koopman, R. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schmidt, J. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-10-16

    The objective of this project was to provide DOD and the intelligence agencies with highly portable, advanced, bio-detection instruments and to further the DOE objective of putting advanced instrumentation for the detection of biological terrorism agents into the hands of first responders. All sponsors of the HANAA development work at LLNL believed that the technology must be commercialized to fully contribute to their missions. Intelligence organizations, military teams, and first responders must be able to purchase the instruments for a reasonable price and obtain maintenance services and support equipment from a reliable supplier in order for the instrument to be useful to them. The goal was to efficiently transfer HANAA technology from LLNL to ETG, a company that would manufacture the instrument and make it commercially available to the constituencies important to our sponsors. This was to include a current beta test instrument and all knowledge of problems with the instrument and recommendations for solving those problems in a commercial version. The following tasks were to be completed under this CRADA.

  11. Fracture mechanisms and fracture control in composite structures

    Science.gov (United States)

    Kim, Wone-Chul

    Four basic failure modes--delamination, delamination buckling of composite sandwich panels, first-ply failure in cross-ply laminates, and compression failure--are analyzed using linear elastic fracture mechanics (LEFM) and the J-integral method. Structural failures, including those at the micromechanical level, are investigated with the aid of the models developed, and the critical strains for crack propagation for each mode are obtained. In the structural fracture analyses area, the fracture control schemes for delamination in a composite rib stiffener and delamination buckling in composite sandwich panels subjected to in-plane compression are determined. The critical fracture strains were predicted with the aid of LEFM for delamination and the J-integral method for delamination buckling. The use of toughened matrix systems has been recommended for improved damage tolerant design for delamination crack propagation. An experimental study was conducted to determine the onset of delamination buckling in composite sandwich panel containing flaws. The critical fracture loads computed using the proposed theoretical model and a numerical computational scheme closely followed the experimental measurements made on sandwich panel specimens of graphite/epoxy faceskins and aluminum honeycomb core with varying faceskin thicknesses and core sizes. Micromechanical models of fracture in composites are explored to predict transverse cracking of cross-ply laminates and compression fracture of unidirectional composites. A modified shear lag model which takes into account the important role of interlaminar shear zones between the 0 degree and 90 degree piles in cross-ply laminate is proposed and criteria for transverse cracking have been developed. For compressive failure of unidirectional composites, pre-existing defects play an important role. Using anisotropic elasticity, the stress state around a defect under a remotely applied compressive load is obtained. The experimentally

  12. CENER/NREL Collaboration in Testing Facility and Code Development: Cooperative Research and Development Final Report, CRADA Number CRD-06-207

    Energy Technology Data Exchange (ETDEWEB)

    Moriarty, P.

    2014-11-01

    Under the funds-in CRADA agreement, NREL and CENER will collaborate in the areas of blade and drivetrain testing facility development and code development. The project shall include NREL assisting in the review and instruction necessary to assist in commissioning the new CENER blade test and drivetrain test facilities. In addition, training will be provided by allowing CENER testing staff to observe testing and operating procedures at the NREL blade test and drivetrain test facilities. CENER and NREL will exchange blade and drivetrain facility and equipment design and performance information. The project shall also include exchanging expertise in code development and data to validate numerous computational codes.

  13. High temperature resin matrix composites for aerospace structures

    Science.gov (United States)

    Davis, J. G., Jr.

    1980-01-01

    Accomplishments and the outlook for graphite-polyimide composite structures are briefly outlined. Laminates, skin-stiffened and honeycomb sandwich panels, chopped fiber moldings, and structural components were fabricated with Celion/LARC-160 and Celion/PMR-15 composite materials. Interlaminar shear and flexure strength data obtained on as-fabricated specimens and specimens that were exposed for 125 hours at 589 K indicate that epoxy sized and polyimide sized Celion graphite fibers exhibit essentially the same behavior in a PMR-15 matrix composite. Analyses and tests of graphite-polyimide compression and shear panels indicate that utilization in moderately loaded applications offers the potential for achieving a 30 to 50 percent reduction in structural mass compared to conventional aluminum panels. Data on effects of moisture, temperature, thermal cycling, and shuttle fluids on mechanical properties indicate that both LARC-160 and PMR-15 are suitable matrix materials for a graphite-polyimide aft body flap. No technical road blocks to building a graphite-polyimide composite aft body flap are identified.

  14. In-situ poling and structurization of piezoelectric particulate composites.

    Science.gov (United States)

    Khanbareh, H; van der Zwaag, S; Groen, W A

    2017-11-01

    Composites of lead zirconate titanate particles in an epoxy matrix are prepared in the form of 0-3 and quasi 1-3 with different ceramic volume contents from 10% to 50%. Two different processing routes are tested. Firstly a conventional dielectrophoretic structuring is used to induce a chain-like particle configuration, followed by curing the matrix and poling at a high temperature and under a high voltage. Secondly a simultaneous combination of dielectrophoresis and poling is applied at room temperature while the polymer is in the liquid state followed by subsequent curing. This new processing route is practiced in an uncured thermoset system while the polymer matrix still possess a relatively high electrical conductivity. Composites with different degrees of alignment are produced by altering the magnitude of the applied electric field. A significant improvement in piezoelectric properties of quasi 1-3 composites can be achieved by a combination of dielectrophoretic alignment of the ceramic particles and poling process. It has been observed that the degree of structuring as well as the functional properties of the in-situ structured and poled composites enhance significantly compared to those of the conventionally manufactured structured composites. Improving the alignment quality enhances the piezoelectric properties of the particulate composites.

  15. Floristic Composition and Structure of Yegof Mountain Forest, South ...

    African Journals Online (AJOL)

    Floristic Composition and Structure of Yegof Mountain Forest, South Wollo, Ethiopia. S Mohammed, B Abraha. Abstract. In this study, Floristic composition, diversity, population structure and regeneration status of woody plant species of Yegof Forest in South Wollo Zone, Amhara Regional State, Ethiopia were analyzed.

  16. Versatile hydrothermal synthesis of one-dimensional composite structures

    Science.gov (United States)

    Luo, Yonglan

    2008-12-01

    In this paper we report on a versatile hydrothermal approach developed to fabricate one-dimensional (1D) composite structures. Sulfur and selenium formed liquid and adsorbed onto microrods as droplets and subsequently reacted with metallic ion in solution to produce nanoparticles-decorated composite microrods. 1D composites including ZnO/CdS, ZnO/MnS, ZnO/CuS, ZnO/CdSe, and FeOOH/CdS were successfully made using this hydrothermal strategy and the growth mechanism was also discussed. This hydrothermal strategy is simple and green, and can be extended to the synthesis of various 1D composite structures. Moreover, the interaction between the shell nanoparticles and the one-dimensional nanomaterials were confirmed by photoluminescence investigation of ZnO/CdS.

  17. On the Mechanical Behavior of Advanced Composite Material Structures

    Science.gov (United States)

    Vinson, Jack

    During the period between 1993 and 2004, the author, as well as some colleagues and graduate students, had the honor to be supported by the Office of Naval Research to conduct research in several aspects of the behavior of structures composed of composite materials. The topics involved in this research program were numerous, but all contributed to increasing the understanding of how various structures that are useful for marine applications behaved. More specifically, the research topics focused on the reaction of structures that were made of fiber reinforced polymer matrix composites when subjected to various loads and environmental conditions. This included the behavior of beam, plate/panel and shell structures. It involved studies that are applicable to fiberglass, graphite/carbon and Kevlar fibers imbedded in epoxy, polyester and other polymeric matrices. Unidirectional, cross-ply, angle ply, and woven composites were involved, both in laminated, monocoque as well as in sandwich constructions. Mid-plane symmetric as well as asymmetric laminates were studied, the latter involving bending-stretching coupling and other couplings that only can be achieved with advanced composite materials. The composite structures studied involved static loads, dynamic loading, shock loading as well as thermal and hygrothermal environments. One major consideration was determining the mechanical properties of composite materials subjected to high strain rates because the mechanical properties vary so significantly as the strain rate increases. A considerable number of references are cited for further reading and study for those interested.

  18. Composition-Structure-Property Relationships in Boroaluminosilicate Glasses

    DEFF Research Database (Denmark)

    Zheng, Qiuju; Potuzak, M.; Mauro, J.C.

    2012-01-01

    boroaluminosilicate glasses from peralkaline to peraluminous compositions by substituting Al2O3 for SiO2. Our results reveal a pronounced change in all the measured physical properties (density, elastic moduli, hardness, glass transition temperature, and liquid fragility) around [Al2O3]–[Na2O]=0. The structural......The complicated structural speciation in boroaluminosilicate glasses leads to a mixed network former effect yielding nonlinear variation in many macroscopic properties as a function of chemical composition. Here we study the composition–structure–property relationships in a series of sodium...

  19. Superelastic SMA–FRP composite reinforcement for concrete structures

    International Nuclear Information System (INIS)

    Wierschem, Nicholas; Andrawes, Bassem

    2010-01-01

    For many years there has been interest in using fiber-reinforced polymers (FRPs) as reinforcement in concrete structures. Unfortunately, due to their linear elastic behavior, FRP reinforcing bars are never considered for structural damping or dynamic applications. With the aim of improving the ductility and damping capability of concrete structures reinforced with FRP reinforcement, this paper studies the application of SMA–FRP, a relatively novel type of composite reinforced with superelastic shape memory alloy (SMA) wires. The cyclic tensile behavior of SMA–FRP composites are studied experimentally and analytically. Tests of SMA–FRP composite coupons are conducted to determine their constitutive behavior. The experimental results are used to develop and calibrate a uniaxial SMA–FRP analytical model. Parametric and case studies are performed to determine the efficacy of the SMA–FRP reinforcement in concrete structures and the key factors governing its behavior. The results show significant potential for SMA–FRP reinforcement to improve the ductility and damping of concrete structures while still maintaining its elastic characteristic, typical of FRP reinforcement

  20. Inside-Out Manufacturing of Composite Structures

    Data.gov (United States)

    National Aeronautics and Space Administration — Tooling for the manufacture of large structures from composite materials often costs much more than individual parts, rendering the processes unattractive for...

  1. Production defects in marine composite structures

    DEFF Research Database (Denmark)

    Hayman, Brian; Berggreen, Christian; Tsouvalis, Nicholas G.

    2007-01-01

    Composite structures are often used when there is a requirement for low weight. Then a key aspect is to be able to take full advantage of the material and utilise it to its limits. To do this it is important to achieve as low a variability as possible in the manufacture of such structures...

  2. Composite materials application on FORMOSAT-5 remote sensing instrument structure

    Directory of Open Access Journals (Sweden)

    Jen-Chueh Kuo

    2017-01-01

    Full Text Available Composite material has been widely applied in space vehicle structures due to its light weight and designed stiffness modulus. Some special mechanical properties that cannot be changed in general metal materials, such as low CTE (coefficient of thermal expansion and directional material stiffness can be artificially adjusted in composite materials to meet the user’s requirements. Space-qualified Carbon Fiber Reinforced Plastic (CFRP composite materials are applied In the FORMOSAT-5 Remote Sensing (RSI structure because of its light weight and low CTE characteristics. The RSI structural elements include the primary mirror supporting plate, secondary mirror supporting ring, and supporting frame. These elements are designed, manufactured, and verified using composite materials to meet specifications. The structure manufacturing process, detailed material properties, and CFRP structural element validation methods are introduced in this paper.

  3. Damage assessment of composite plate structures with material and measurement uncertainty

    Science.gov (United States)

    Chandrashekhar, M.; Ganguli, Ranjan

    2016-06-01

    Composite materials are very useful in structural engineering particularly in weight sensitive applications. Two different test models of the same structure made from composite materials can display very different dynamic behavior due to large uncertainties associated with composite material properties. Also, composite structures can suffer from pre-existing imperfections like delaminations, voids or cracks during fabrication. In this paper, we show that modeling and material uncertainties in composite structures can cause considerable problem in damage assessment. A recently developed C0 shear deformable locking free refined composite plate element is employed in the numerical simulations to alleviate modeling uncertainty. A qualitative estimate of the impact of modeling uncertainty on the damage detection problem is made. A robust Fuzzy Logic System (FLS) with sliding window defuzzifier is used for delamination damage detection in composite plate type structures. The FLS is designed using variations in modal frequencies due to randomness in material properties. Probabilistic analysis is performed using Monte Carlo Simulation (MCS) on a composite plate finite element model. It is demonstrated that the FLS shows excellent robustness in delamination detection at very high levels of randomness in input data.

  4. Implementing optical fibres for the structural health monitoring of composite patch repaired structures

    DEFF Research Database (Denmark)

    Karatzas, Vasileios; Kotsidis, Elias A.; Tsouvalis, Nicholas G.

    2017-01-01

    Structural health monitoring is increasingly being implemented to improve the level of safety of structures and to reduce inspection and repair costs by allowing for correct planning of these actions, if needed. Composite patch repairing presents an appealing alternative to traditional repair...... methods as it enables the reduction of closedown time and the mitigation of complications associated with traditional repair methods. As reinforcement with the use of composite patches is predominantly performed at defected structures, the urge to monitor the performance of the repair becomes even greater...

  5. Predictive Model and Methodology for Heat Treatment Distortion Final Report CRADA No. TC-298-92

    Energy Technology Data Exchange (ETDEWEB)

    Nikkel, D. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McCabe, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-10-16

    This project was a multi-lab, multi-partner CRADA involving LLNL, Los Alamos National Laboratory, Sandia National Laboratories, Oak Ridge National Laboratory, Martin Marietta Energy Systems and the industrial partner, The National Center of Manufacturing Sciences (NCMS). A number of member companies of NCMS participated including General Motors Corporation, Ford Motor Company, The Torrington Company, Gear Research, the Illinois Institute of Technology Research Institute, and Deformation Control Technology •. LLNL was the lead laboratory for metrology technology used for validation of the computational tool/methodology. LLNL was also the lead laboratory for the development of the software user interface , for the computational tool. This report focuses on the participation of LLNL and NCMS. The purpose of the project was to develop a computational tool/methodology that engineers would use to predict the effects of heat treatment on the _size and shape of industrial parts made of quench hardenable alloys. Initially, the target application of the tool was gears for automotive power trains.

  6. Structure-Composition-Property Relationships in Polymeric Amorphous Calcium Phosphate-Based Dental Composites

    Directory of Open Access Journals (Sweden)

    Drago Skrtic

    2009-11-01

    Full Text Available Our studies of amorphous calcium phosphate (ACP-based materials over the last decade have yielded bioactive polymeric composites capable of protecting teeth from demineralization or even regenerating lost tooth mineral. The anti-cariogenic/remineralizing potential of these ACP composites originates from their propensity, when exposed to the oral environment, to release in a sustained manner sufficient levels of mineral-forming calcium and phosphate ions to promote formation of stable apatitic tooth mineral. However, the less than optimal ACP filler/resin matrix cohesion, excessive polymerization shrinkage and water sorption of these experimental materials can adversely affect their physicochemical and mechanical properties, and, ultimately, limit their lifespan. This study demonstrates the effects of chemical structure and composition of the methacrylate monomers used to form the matrix phase of composites on degree of vinyl conversion (DVC and water sorption of both copolymers and composites and the release of mineral ions from the composites. Modification of ACP surface via introducing cations and/or polymers ab initio during filler synthesis failed to yield mechanically improved composites. However, moderate improvement in composite’s mechanical stability without compromising its remineralization potential was achieved by silanization and/or milling of ACP filler. Using ethoxylated bisphenol A dimethacrylate or urethane dimethacrylate as base monomers and adding moderate amounts of hydrophilic 2-hydroxyethyl methacrylate or its isomer ethyl-α-hydroxymethacrylate appears to be a promising route to maximize the remineralizing ability of the filler while maintaining high DVC. Exploration of the structure/composition/property relationships of ACP fillers and polymer matrices is complex but essential for achieving a better understanding of the fundamental mechanisms that govern dissolution/re-precipitation of bioactive ACP fillers, and

  7. 75 FR 793 - Damage Tolerance and Fatigue Evaluation of Composite Rotorcraft Structures

    Science.gov (United States)

    2010-01-06

    ... metal structures are different. Composites are complex materials that have unique advantages in fatigue... stiffness, dynamic behavior, loads, and functional performance of composite structures. In the existing rule... and Fatigue Evaluation of Composite Rotorcraft Structures AGENCY: Federal Aviation Administration (FAA...

  8. Piezoelectric and mechanical properties of structured PZT-epoxy composites

    NARCIS (Netherlands)

    James, N.K.; Ende, D.A. van den; Lafont, U.; Zwaag, S. van der; Groen, W.A.

    2013-01-01

    Structured lead zirconium titanate (PZT)-epoxy composites are prepared by dielectrophoresis. The piezoelectric and dielectric properties of the composites as a function of PZT volume fraction are investigated and compared with the corresponding unstructured composites. The effect of poling voltage

  9. Piezoelectric and mechanical properties of structured PZT–epoxy composites

    NARCIS (Netherlands)

    Kunnamkuzhakkal James, N.; Van den Ende, D.; Lafont, U.; Van der Zwaag, S.; Groen, W.A.

    2013-01-01

    Structured lead zirconium titanate (PZT)–epoxy composites are prepared by dielectrophoresis. The piezoelectric and dielectric properties of the composites as a function of PZT volume fraction are investigated and compared with the corresponding unstructured composites. The effect of poling voltage

  10. Shear wave propagation in piezoelectric-piezoelectric composite layered structure

    Directory of Open Access Journals (Sweden)

    Anshu Mli Gaur

    Full Text Available The propagation behavior of shear wave in piezoelectric composite structure is investigated by two layer model presented in this approach. The composite structure comprises of piezoelectric layers of two different materials bonded alternatively. Dispersion equations are derived for propagation along the direction normal to the layering and in direction of layering. It has been revealed that thickness and elastic constants have significant influence on propagation behavior of shear wave. The phase velocity and wave number is numerically calculated for alternative layer of Polyvinylidene Difluoride (PVDF and Lead Zirconate Titanate (PZT-5H in composite layered structure. The analysis carried out in this paper evaluates the effect of volume fraction on the phase velocity of shear wave.

  11. Mechanical Properties Of 3D-Structure Composites Based On Warp-Knitted Spacer Fabrics

    Directory of Open Access Journals (Sweden)

    Chen Si

    2015-06-01

    Full Text Available In this paper, the mechanical properties (compression and impact behaviours of three-dimension structure (3D-structure composites based on warp-knitted spacer fabrics have been thoroughly investigated. In order to discuss the effect of fabric structural parameters on the mechanical performance of composites, six different types of warp-knitted spacer fabrics having different structural parameters (such as outer layer structure, diameter of spacer yarn, spacer yarn inclination angle and thickness were involved for comparison study. The 3D-structure composites were fabricated based on a flexible polyurethane foam. The produced composites were characterised for compression and impact properties. The findings obtained indicate that the fabric structural parameters have strong influence on the compression and impact responses of 3D-structure composites. Additionally, the impact test carried out on the 3D-structure composites shows that the impact loads do not affect the integrity of composite structure. All the results reveal that the product exhibits promising mechanical performance and its service life can be sustained.

  12. Analysis of Smart Composite Structures Including Debonding

    Science.gov (United States)

    Chattopadhyay, Aditi; Seeley, Charles E.

    1997-01-01

    Smart composite structures with distributed sensors and actuators have the capability to actively respond to a changing environment while offering significant weight savings and additional passive controllability through ply tailoring. Piezoelectric sensing and actuation of composite laminates is the most promising concept due to the static and dynamic control capabilities. Essential to the implementation of these smart composites are the development of accurate and efficient modeling techniques and experimental validation. This research addresses each of these important topics. A refined higher order theory is developed to model composite structures with surface bonded or embedded piezoelectric transducers. These transducers are used as both sensors and actuators for closed loop control. The theory accurately captures the transverse shear deformation through the thickness of the smart composite laminate while satisfying stress free boundary conditions on the free surfaces. The theory is extended to include the effect of debonding at the actuator-laminate interface. The developed analytical model is implemented using the finite element method utilizing an induced strain approach for computational efficiency. This allows general laminate geometries and boundary conditions to be analyzed. The state space control equations are developed to allow flexibility in the design of the control system. Circuit concepts are also discussed. Static and dynamic results of smart composite structures, obtained using the higher order theory, are correlated with available analytical data. Comparisons, including debonded laminates, are also made with a general purpose finite element code and available experimental data. Overall, very good agreement is observed. Convergence of the finite element implementation of the higher order theory is shown with exact solutions. Additional results demonstrate the utility of the developed theory to study piezoelectric actuation of composite

  13. Silver Matrix Composites - Structure and Properties

    Directory of Open Access Journals (Sweden)

    Wieczorek J.

    2016-03-01

    Full Text Available Phase compositions of composite materials determine their performance as well as physical and mechanical properties. Depending on the type of applied matrix and the kind, amount and morphology of the matrix reinforcement, it is possible to shape the material properties so that they meet specific operational requirements. In the paper, results of investigations on silver alloy matrix composites reinforced with ceramic particles are presented. The investigations enabled evaluation of hardness, tribological and mechanical properties as well as the structure of produced materials. The matrix of composite material was an alloy of silver and aluminium, magnesium and silicon. As the reinforcing phase, 20-60 μm ceramic particles (SiC, SiO2, Al2O3 and Cs were applied. The volume fraction of the reinforcing phase in the composites was 10%. The composites were produced using the liquid phase (casting technology, followed by plastic work (the KOBO method. The mechanical and tribological properties were analysed for plastic work-subjected composites. The mechanical properties were assessed based on a static tensile and hardness tests. The tribological properties were investigated under dry sliding conditions. The analysis of results led to determination of effects of the composite production technology on their performance. Moreover, a relationship between the type of reinforcing phase and the mechanical and tribological properties was established.

  14. Topology Optimization of Lightweight Lattice Structural Composites Inspired by Cuttlefish Bone

    Science.gov (United States)

    Hu, Zhong; Gadipudi, Varun Kumar; Salem, David R.

    2018-03-01

    Lattice structural composites are of great interest to various industries where lightweight multifunctionality is important, especially aerospace. However, strong coupling among the composition, microstructure, porous topology, and fabrication of such materials impedes conventional trial-and-error experimental development. In this work, a discontinuous carbon fiber reinforced polymer matrix composite was adopted for structural design. A reliable and robust design approach for developing lightweight multifunctional lattice structural composites was proposed, inspired by biomimetics and based on topology optimization. Three-dimensional periodic lattice blocks were initially designed, inspired by the cuttlefish bone microstructure. The topologies of the three-dimensional periodic blocks were further optimized by computer modeling, and the mechanical properties of the topology optimized lightweight lattice structures were characterized by computer modeling. The lattice structures with optimal performance were identified.

  15. Advanced organic composite materials for aircraft structures: Future program

    Science.gov (United States)

    1987-01-01

    Revolutionary advances in structural materials have been responsible for revolutionary changes in all fields of engineering. These advances have had and are still having a significant impact on aircraft design and performance. Composites are engineered materials. Their properties are tailored through the use of a mix or blend of different constituents to maximize selected properties of strength and/or stiffness at reduced weights. More than 20 years have passed since the potentials of filamentary composite materials were identified. During the 1970s much lower cost carbon filaments became a reality and gradually designers turned from boron to carbon composites. Despite progress in this field, filamentary composites still have significant unfulfilled potential for increasing aircraft productivity; the rendering of advanced organic composite materials into production aircraft structures was disappointingly slow. Why this is and research and technology development actions that will assist in accelerating the application of advanced organic composites to production aircraft is discussed.

  16. Band Structure Characteristics of Nacreous Composite Materials with Various Defects

    Science.gov (United States)

    Yin, J.; Zhang, S.; Zhang, H. W.; Chen, B. S.

    2016-06-01

    Nacreous composite materials have excellent mechanical properties, such as high strength, high toughness, and wide phononic band gap. In order to research band structure characteristics of nacreous composite materials with various defects, supercell models with the Brick-and-Mortar microstructure are considered. An efficient multi-level substructure algorithm is employed to discuss the band structure. Furthermore, two common systems with point and line defects and varied material parameters are discussed. In addition, band structures concerning straight and deflected crack defects are calculated by changing the shear modulus of the mortar. Finally, the sensitivity of band structures to the random material distribution is presented by considering different volume ratios of the brick. The results reveal that the first band gap of a nacreous composite material is insensitive to defects under certain conditions. It will be of great value to the design and synthesis of new nacreous composite materials for better dynamic properties.

  17. Structure and Properties of LENRA/ Silica Composite

    International Nuclear Information System (INIS)

    Mahathir Mohamed; Dahlan Mohd

    2010-01-01

    The sol-gel reaction using tetra ethoxysilane (TEOS) was conducted for modified natural rubber (NR) matrix to obtain in situ generated NR/ silica composite. The present of acrylate group in the modified NR chain turns the composite into radiation-curable. The maximum amount of silica generated in the matrix was 50 p hr by weight. During the sol-gel process the inorganic mineral was deposited in the rubber matrix forming hydrogen bonding between organic and inorganic phases. The composites obtained were characterized by various techniques including thermogravimetric analysis and infrared spectrometry to study their molecular structure. The increase in mechanical properties was observed for low silica contents ( 30 p hr) where more silica were generated, agglomerations were observed at the expense of the mechanical properties. From the DMTA data, it shows an increase of the interaction between the rubber and silica phases up to 30 p hr TEOS. Structure and morphology of the heterogeneous system were analyzed by transmission electron microscopy. The average particle sizes of between 150 nm to 300 nm were achieved for the composites that contain less than 20 p hr of TEOS. (author)

  18. The crack energy absorptive capacity of composites with fractal structure

    International Nuclear Information System (INIS)

    Lung, C.W.

    1990-11-01

    This paper discusses the energy absorptive capacity of composites with fibers of fractal structures. It is found that this kind of structure may increase the absorption energy during the crack propagation and hence the fracture toughness of composites. (author). 10 refs, 6 figs, 2 tabs

  19. Sandwich Structured Composites for Aeronautics: Methods of Manufacturing Affecting Some Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Aneta Krzyżak

    2016-01-01

    Full Text Available Sandwich panels are composites which consist of two thin laminate outer skins and lightweight (e.g., honeycomb thick core structure. Owing to the core structure, such composites are distinguished by stiffness. Despite the thickness of the core, sandwich composites are light and have a relatively high flexural strength. These composites have a spatial structure, which affects good thermal insulator properties. Sandwich panels are used in aeronautics, road vehicles, ships, and civil engineering. The mechanical properties of these composites are directly dependent on the properties of sandwich components and method of manufacturing. The paper presents some aspects of technology and its influence on mechanical properties of sandwich structure polymer composites. The sandwiches described in the paper were made by three different methods: hand lay-up, press method, and autoclave use. The samples of sandwiches were tested for failure caused by impact load. Sandwiches prepared in the same way were used for structural analysis of adhesive layer between panels and core. The results of research showed that the method of manufacturing, more precisely the pressure while forming sandwich panels, influences some mechanical properties of sandwich structured polymer composites such as flexural strength, impact strength, and compressive strength.

  20. Structural characterization and lipid composition of acquired cholesteatoma

    DEFF Research Database (Denmark)

    Bloksgaard, Maria; Svane-Knudsen, Viggo; Sørensen, Jens A

    2012-01-01

    HYPOTHESIS: The goal of this work is to characterize the morphology and lipid composition of acquired cholesteatoma. We hypothesize that constitutive lipid membranes are present in the cholesteatoma and resemble those found in human skin stratum corneum. METHODS: We performed a comparative...... noninvasive structural and lipid compositional study of acquired cholesteatoma and control human skin using multiphoton excitation fluorescence microscopy-related techniques and high-performance thin-layer chromatography. RESULTS: The structural arrangement of the cholesteatoma is morphologically invariant...... along a depth of more than 200 μm and resembles the stratum corneum of hyperorthokeratotic skin. Lipid compositional analyses of the cholesteatoma show the presence of all major lipid classes found in normal skin stratum corneum (ceramides, long chain fatty acids, and cholesterol). Consistent with this...

  1. Low-Cost Composite Materials and Structures for Aircraft Applications

    Science.gov (United States)

    Deo, Ravi B.; Starnes, James H., Jr.; Holzwarth, Richard C.

    2003-01-01

    A survey of current applications of composite materials and structures in military, transport and General Aviation aircraft is presented to assess the maturity of composites technology, and the payoffs realized. The results of the survey show that performance requirements and the potential to reduce life cycle costs for military aircraft and direct operating costs for transport aircraft are the main reasons for the selection of composite materials for current aircraft applications. Initial acquisition costs of composite airframe components are affected by high material costs and complex certification tests which appear to discourage the widespread use of composite materials for aircraft applications. Material suppliers have performed very well to date in developing resin matrix and fiber systems for improved mechanical, durability and damage tolerance performance. The next challenge for material suppliers is to reduce material costs and to develop materials that are suitable for simplified and inexpensive manufacturing processes. The focus of airframe manufacturers should be on the development of structural designs that reduce assembly costs by the use of large-scale integration of airframe components with unitized structures and manufacturing processes that minimize excessive manual labor.

  2. Structural Composite Supercapacitors: Electrical and Mechanical Impact of Separators and Processing Conditions

    Science.gov (United States)

    2013-09-01

    Structural Composite Supercapacitors : Electrical and Mechanical Impact of Separators and Processing Conditions by Edwin B. Gienger, James F...Proving Ground, MD 21005-5066 ARL-TR-6624 September 2013 Structural Composite Supercapacitors : Electrical and Mechanical Impact of...2012 4. TITLE AND SUBTITLE Structural Composite Supercapacitors : Electrical and Mechanical Impact of Separators and Processing Conditions 5a

  3. Structural Acoustic Physics Based Modeling of Curved Composite Shells

    Science.gov (United States)

    2017-09-19

    NUWC-NPT Technical Report 12,236 19 September 2017 Structural Acoustic Physics -Based Modeling of Curved Composite Shells Rachel E. Hesse...SUBTITLE Structural Acoustic Physics -Based Modeling of Curved Composite Shells 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...study was to use physics -based modeling (PBM) to investigate wave propagations through curved shells that are subjected to acoustic excitation. An

  4. Fabricating Composite-Material Structures Containing SMA Ribbons

    Science.gov (United States)

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

    2003-01-01

    An improved method of designing and fabricating laminated composite-material (matrix/fiber) structures containing embedded shape-memory-alloy (SMA) actuators has been devised. Structures made by this method have repeatable, predictable properties, and fabrication processes can readily be automated. Such structures, denoted as shape-memory-alloy hybrid composite (SMAHC) structures, have been investigated for their potential to satisfy requirements to control the shapes or thermoelastic responses of themselves or of other structures into which they might be incorporated, or to control noise and vibrations. Much of the prior work on SMAHC structures has involved the use SMA wires embedded within matrices or within sleeves through parent structures. The disadvantages of using SMA wires as the embedded actuators include (1) complexity of fabrication procedures because of the relatively large numbers of actuators usually needed; (2) sensitivity to actuator/ matrix interface flaws because voids can be of significant size, relative to wires; (3) relatively high rates of breakage of actuators during curing of matrix materials because of sensitivity to stress concentrations at mechanical restraints; and (4) difficulty of achieving desirable overall volume fractions of SMA wires when trying to optimize the integration of the wires by placing them in selected layers only.

  5. Development of a Delivery System for Treating Cerebrovascular Aneurysms Final Report CRADA No. TC-1440-97

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Derbin, J. T. [Micrus Corp., Mountain View, CA (United States)

    2018-01-24

    The objective of the project was to develop a system for delivering an implantable medical device used to treat cerebrovascular aneurysms, which can cause disability or hemorrhagic stroke (over 15,000 strokes in the U.S. each year are caused by ruptured aneurysms). Micrus has developed an implantable device with the potential to significantly improve the treatment of cerebrovascular aneurysms. This implantable device should significantly reduce the number of hemorrhagic strokes. LLNL has performed proof-of-concept experiments for a delivery system that could be modified to deploy the Micrus device into aneurysms. The purpose of this CRADA was to complete development of the LLNL delivery system and to integrate it with the Micrus device. The goal of the project was to develop an integrated minimally-invasive medical device for treating cerebrovascular aneurysms. The device was designed to access aneurysms through commercially-available catheters which are introduced into the patient through a small incision in the leg.

  6. Carbon fiber epoxy composites for both strengthening and health monitoring of structures.

    Science.gov (United States)

    Salvado, Rita; Lopes, Catarina; Szojda, Leszek; Araújo, Pedro; Gorski, Marcin; Velez, Fernando José; Castro-Gomes, João; Krzywon, Rafal

    2015-05-06

    This paper presents a study of the electrical and mechanical behavior of several continuous carbon fibers epoxy composites for both strengthening and monitoring of structures. In these composites, the arrangement of fibers was deliberately diversified to test and understand the ability of the composites for self-sensing low strains. Composites with different arrangements of fibers and textile weaves, mainly unidirectional continuous carbon reinforced composites, were tested at the dynamometer. A two-probe method was considered to measure the relative electrical resistance of these composites during loading. The measured relative electrical resistance includes volume and contact electrical resistances. For all tested specimens, it increases with an increase in tensile strain, at low strain values. This is explained by the improved alignment of fibers and resulting reduction of the number of possible contacts between fibers during loading, increasing as a consequence the contact electrical resistance of the composite. Laboratory tests on strengthening of structural elements were also performed, making hand-made composites by the "wet process", which is commonly used in civil engineering for the strengthening of all types of structures in-situ. Results show that the woven epoxy composite, used for strengthening of concrete elements is also able to sense low deformations, below 1%. Moreover, results clearly show that this textile sensor also improves the mechanical work of the strengthened structural elements, increasing their bearing capacity. Finally, the set of obtained results supports the concept of a textile fabric capable of both structural upgrade and self-monitoring of structures, especially large structures of difficult access and needing constant, sometimes very expensive, health monitoring.

  7. Carbon Nanotube Enhanced Aerospace Composite Materials A New Generation of Multifunctional Hybrid Structural Composites

    CERN Document Server

    Kostopoulos, V

    2013-01-01

    The well documented increase in the use of high performance composites as structural materials in aerospace components is continuously raising the demands in terms of dynamic performance, structural integrity, reliable life monitoring systems and adaptive actuating abilities. Current technologies address the above issues separately; material property tailoring and custom design practices aim to the enhancement of dynamic and damage tolerance characteristics, whereas life monitoring and actuation is performed with embedded sensors that may be detrimental to the structural integrity of the component. This publication explores the unique properties of carbon nanotubes (CNT) as an additive in the matrix of Fibre Reinforced Plastics (FRP), for producing structural composites with improved mechanical performance as well as sensing/actuating capabilities. The successful combination of the CNT properties and existing sensing actuating technologies leads to the realization of a multifunctional FRP structure. The curre...

  8. Experimental identification of smart material coupling effects in composite structures

    International Nuclear Information System (INIS)

    Chesne, S; Jean-Mistral, C; Gaudiller, L

    2013-01-01

    Smart composite structures have an enormous potential for industrial applications, in terms of mass reduction, high material resistance and flexibility. The correct characterization of these complex structures is essential for active vibration control or structural health monitoring applications. The identification process generally calls for the determination of a generalized electromechanical coupling coefficient. As this process can in practice be difficult to implement, an original approach, presented in this paper, has been developed for the identification of the coupling effects of a smart material used in a composite curved beam. The accuracy of the proposed identification technique is tested by applying active modal control to the beam, using a reduced model based on this identification. The studied structure was as close to reality as possible, and made use of integrated transducers, low-cost sensors, clamped boundary conditions and substantial, complex excitation sources. PVDF (polyvinylidene fluoride) and MFC (macrofiber composite) transducers were integrated into the composite structure, to ensure their protection from environmental damage. The experimental identification described here was based on a curve fitting approach combined with the reduced model. It allowed a reliable, powerful modal control system to be built, controlling two modes of the structure. A linear quadratic Gaussian algorithm was used to determine the modal controller–observer gains. The selected modes were found to have an attenuation as strong as −13 dB in experiments, revealing the effectiveness of this method. In this study a generalized approach is proposed, which can be extended to most complex or composite industrial structures when they are subjected to vibration. (paper)

  9. Simulating the structure of gypsum composites using pulverized basalt waste

    Directory of Open Access Journals (Sweden)

    Buryanov Аleksandr

    2017-01-01

    Full Text Available This paper examines the possibility of simulating the structure of gypsum composite modified with basalt dust waste to make materials and products based on it. Structural simulating of the topological space in gypsum modified composite by optimizing its grain-size composition highly improves its physical and mechanical properties. Strength and density tests have confirmed the results of the simulation. The properties of modified gypsum materials are improved by obtaining of denser particle packing in the presence of hemihydrate of finely dispersed basalt and plasticizer particles in the system, and by engaging basalt waste in the structuring process of modified gypsum stone.

  10. Energy Finite Element Analysis Developments for Vibration Analysis of Composite Aircraft Structures

    Science.gov (United States)

    Vlahopoulos, Nickolas; Schiller, Noah H.

    2011-01-01

    The Energy Finite Element Analysis (EFEA) has been utilized successfully for modeling complex structural-acoustic systems with isotropic structural material properties. In this paper, a formulation for modeling structures made out of composite materials is presented. An approach based on spectral finite element analysis is utilized first for developing the equivalent material properties for the composite material. These equivalent properties are employed in the EFEA governing differential equations for representing the composite materials and deriving the element level matrices. The power transmission characteristics at connections between members made out of non-isotropic composite material are considered for deriving suitable power transmission coefficients at junctions of interconnected members. These coefficients are utilized for computing the joint matrix that is needed to assemble the global system of EFEA equations. The global system of EFEA equations is solved numerically and the vibration levels within the entire system can be computed. The new EFEA formulation for modeling composite laminate structures is validated through comparison to test data collected from a representative composite aircraft fuselage that is made out of a composite outer shell and composite frames and stiffeners. NASA Langley constructed the composite cylinder and conducted the test measurements utilized in this work.

  11. Carbon Fiber Epoxy Composites for Both Strengthening and Health Monitoring of Structures

    Directory of Open Access Journals (Sweden)

    Rita Salvado

    2015-05-01

    Full Text Available This paper presents a study of the electrical and mechanical behavior of several continuous carbon fibers epoxy composites for both strengthening and monitoring of structures. In these composites, the arrangement of fibers was deliberately diversified to test and understand the ability of the composites for self-sensing low strains. Composites with different arrangements of fibers and textile weaves, mainly unidirectional continuous carbon reinforced composites, were tested at the dynamometer. A two-probe method was considered to measure the relative electrical resistance of these composites during loading. The measured relative electrical resistance includes volume and contact electrical resistances. For all tested specimens, it increases with an increase in tensile strain, at low strain values. This is explained by the improved alignment of fibers and resulting reduction of the number of possible contacts between fibers during loading, increasing as a consequence the contact electrical resistance of the composite. Laboratory tests on strengthening of structural elements were also performed, making hand-made composites by the “wet process”, which is commonly used in civil engineering for the strengthening of all types of structures in-situ. Results show that the woven epoxy composite, used for strengthening of concrete elements is also able to sense low deformations, below 1%. Moreover, results clearly show that this textile sensor also improves the mechanical work of the strengthened structural elements, increasing their bearing capacity. Finally, the set of obtained results supports the concept of a textile fabric capable of both structural upgrade and self-monitoring of structures, especially large structures of difficult access and needing constant, sometimes very expensive, health monitoring.

  12. Design and Processing of Structural Composite Batteries

    National Research Council Canada - National Science Library

    Wong, E. L; Baechle, D. M; Xu, K; Carter, R. H; Snyder, J. F; Wetzel, E. D

    2007-01-01

    ...) 2007 Symposium and Exhibition held in Baltimore, MD, on 3-7 June 2007. Multifunctional structural composites are being developed to simultaneously bear mechanical loads and store electrochemical energy...

  13. Radiation damage in carbon-carbon composites: Structure and property effects

    International Nuclear Information System (INIS)

    Burchell, T.D.

    1995-01-01

    Carbon-carbon composites are an attractive choice for fusion reactor plasma facing components because of their low atomic number, superior thermal shock resistance, and low neutron activation. Next generation tokamak reactors such as the International Thermonuclear Experimental Reactor (ITER), will require high thermal conductivity carbon-carbon composites and other materials, such as beryllium, to protect their plasma facing components from the anticipated high heat fluxes. Moreover, ignition machines such as ITER will produce a large neutron flux. Consequently, the influence of neutron damage on the structure and properties of carbon-carbon composite materials must be evaluated. Data from two irradiation experiments are reported and discussed here. Carbon-carbon composite materials were irradiated in target capsules in the High Flux Isotope Reactor (HAIR) at Oak Ridge National Laboratory (ORAL). A peak damage dose of 4.7 displacements per atom (da) at an irradiation temperature of ∼600 degrees C was attained. The carbon materials irradiated here included unidirectional, two- directional, and three-directional carbon-carbon composites. Irradiation induced dimensional changes are reported for the materials and related to single crystal dimensional changes through fiber and composite structural models. Moreover, carbon-carbon composite material dimensional changes are discussed in terms of their architecture, fiber type, and graphitization temperature. Neutron irradiation induced reductions in the thermal conductivity of two, three-directional carbon-carbon composites are reported, and the recovery of thermal conductivity due to thermal annealing is demonstrated. Irradiation induced strength changes are reported for several carbon-carbon composite materials and are explained in terms of in-crystal and composite structural effects

  14. Polyurethane structural adhesives applied in automotive composite joints

    Directory of Open Access Journals (Sweden)

    Josue Garcia Quini

    2012-06-01

    Full Text Available In recent years structural adhesives technology has demonstrated great potential for application due to its capacity to transform complex structures into solid unitary and monolithic assemblies using different materials. Thus, seams or joints integrate these structures providing, besides a reduction in weight, a considerable increase in the mechanical resistance and stiffness. The increase in the industrial use of structural adhesives is mainly due to their ability to efficiently bond different materials in an irreversible manner, even replacing systems involving mechanical joints. In the automobile industry structural adhesives have been widely used for the bonding of metal substrates, thermoplastics and composites, frequently employing these in combination, particularly glass fiber and polyester resin composites molded using RTM and SMC processes. However, the use of urethane structural adhesives in applications involving composites and thermoplastics has been the subject of few investigations. In this study the effects of temperature and time on the shear strength of RTM, SMC and ABS joints, applying temperatures of -40, 25, 80, 120 and 177 °C and times of 20 minutes and 500 hours, were determined. The objective was to evaluate the performance under extreme conditions of use in order to assess whether these joints could be used in passenger or off-road vehicles. The results showed that the urethane structural adhesive promoted the efficient bonding of these materials, considering that due to the high adhesive strength the failures occurred in the substrates without adversely affecting the bonded area. For each test condition the joint failure modes were also determined.

  15. Characterization and manufacture of braided composites for large commercial aircraft structures

    Science.gov (United States)

    Fedro, Mark J.; Willden, Kurtis

    1992-01-01

    Braided composite materials, one of the advanced material forms which is under investigation in Boeing's ATCAS program, have been recognized as a potential cost-effective material form for fuselage structural elements. Consequently, there is a strong need for more knowledge in the design, manufacture, test, and analysis of textile structural composites. The overall objective of this work is to advance braided composite technology towards applications to a large commercial transport fuselage. This paper summarizes the mechanics of materials and manufacturing demonstration results which have been obtained in order to acquire an understanding of how braided composites can be applied to a commercial fuselage. Textile composites consisting of 1D, 2D triaxial, and 3D braid patterns with thermoplastic and two RTM resin systems were investigated. The structural performance of braided composites was evaluated through an extensive mechanical test program. Analytical methods were also developed and applied to predict the following: internal fiber architectures, stiffnesses, fiber stresses, failure mechanisms, notch effects, and the entire history of failure of the braided composites specimens. The applicability of braided composites to a commercial transport fuselage was further assessed through a manufacturing demonstration. Three foot fuselage circumferential hoop frames were manufactured to demonstrate the feasibility of consistently producing high quality braided/RTM composite primary structures. The manufacturing issues (tooling requirements, processing requirements, and process/quality control) addressed during the demonstration are summarized. The manufacturing demonstration in conjunction with the mechanical test results and developed analytical methods increased the confidence in the ATCAS approach to the design, manufacture, test, and analysis of braided composites.

  16. Damping Analysis of Cylindrical Composite Structures with Enhanced Viscoelastic Properties

    Science.gov (United States)

    Kliem, Mathias; Høgsberg, Jan; Vanwalleghem, Joachim; Filippatos, Angelos; Hoschützky, Stefan; Fotsing, Edith-Roland; Berggreen, Christian

    2018-04-01

    Constrained layer damping treatments are widely used in mechanical structures to damp acoustic noise and mechanical vibrations. A viscoelastic layer is thereby applied to a structure and covered by a stiff constraining layer. When the structure vibrates in a bending mode, the viscoelastic layer is forced to deform in shear mode. Thus, the vibration energy is dissipated as low grade frictional heat. This paper documents the efficiency of passive constrained layer damping treatments for low frequency vibrations of cylindrical composite specimens made of glass fibre-reinforced plastics. Different cross section geometries with shear webs have been investigated in order to study a beneficial effect on the damping characteristics of the cylinder. The viscoelastic damping layers are placed at different locations within the composite cylinder e.g. circumferential and along the neutral plane to evaluate the location-dependent efficiency of constrained layer damping treatments. The results of the study provide a thorough understanding of constrained layer damping treatments and an improved damping design of the cylindrical composite structure. The highest damping is achieved when placing the damping layer in the neutral plane perpendicular to the bending load. The results are based on free decay tests of the composite structure.

  17. Finite element model updating of natural fibre reinforced composite structure in structural dynamics

    Directory of Open Access Journals (Sweden)

    Sani M.S.M.

    2016-01-01

    Full Text Available Model updating is a process of making adjustment of certain parameters of finite element model in order to reduce discrepancy between analytical predictions of finite element (FE and experimental results. Finite element model updating is considered as an important field of study as practical application of finite element method often shows discrepancy to the test result. The aim of this research is to perform model updating procedure on a composite structure as well as trying improving the presumed geometrical and material properties of tested composite structure in finite element prediction. The composite structure concerned in this study is a plate of reinforced kenaf fiber with epoxy. Modal properties (natural frequency, mode shapes, and damping ratio of the kenaf fiber structure will be determined using both experimental modal analysis (EMA and finite element analysis (FEA. In EMA, modal testing will be carried out using impact hammer test while normal mode analysis using FEA will be carried out using MSC. Nastran/Patran software. Correlation of the data will be carried out before optimizing the data from FEA. Several parameters will be considered and selected for the model updating procedure.

  18. Low Velocity Impact Properties of Aluminum Foam Sandwich Structural Composite

    Directory of Open Access Journals (Sweden)

    ZHAO Jin-hua

    2018-01-01

    Full Text Available Sandwich structural composites were prepared by aluminum foam as core materials with basalt fiber(BF and ultra-high molecular weight polyethylene(UHMWPE fiber composite as faceplate. The effect of factors of different fiber type faceplates, fabric layer design and the thickness of the corematerials on the impact properties and damage mode of aluminum foam sandwich structure was studied. The impact properties were also analyzed to compare with aluminum honeycomb sandwich structure. The results show that BF/aluminum foam sandwich structural composites has bigger impact damage load than UHMWPE/aluminum foam sandwich structure, but less impact displacement and energy absorption. The inter-layer hybrid fabric design of BF and UHMWPE has higher impact load and energy absorption than the overlay hybrid fabric design faceplate sandwich structure. With the increase of the thickness of aluminum foam,the impact load of the sandwich structure decreases, but the energy absorption increases. Aluminum foam sandwich structure has higher impact load than the aluminum honeycomb sandwich structure, but smaller damage energy absorption; the damage mode of aluminum foam core material is mainly the fracture at the impact area, while aluminum honeycomb core has obvious overall compression failure.

  19. Structure evaluation of cast dispersive AlSi-CrxCy composites

    OpenAIRE

    M. Cholewa

    2008-01-01

    In this work author showed the diversification of structure for cast dispersive AlSi-CrxCy composites. Wide possibilities of properties control and optimization were described, through microstructure of the matrix and the transition zone shaping. Utility castings were prepared with use of traditional casting techniques, ceramic and metal moulds. The influence of technological conditions and cooling rate ion the composite structure was studied. The main factor of structural changes was the dif...

  20. Template-free fabrication and morphology regulation of Ag@carbon composite structure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenyan, E-mail: zhangwenyan8531@gmail.com [College of Material Engineering, Jinling Institute of Technology, Nanjing (China); Hao, Lingyun; Lin, Qin [College of Material Engineering, Jinling Institute of Technology, Nanjing (China); Lu, Chunhua; Xu, Zhongzi [College of Materials Science and Engineering, Nanjing Technology University, Nanjing (China); Chen, Xiaoyu [College of Material Engineering, Jinling Institute of Technology, Nanjing (China)

    2014-12-15

    Graphical abstract: - Highlights: • A simple and low-cost method to prepare Ag@C composite material. • AgNO{sub 3} plays an important role in tuning size and functional groups of products. • HTC reaction time is also a key factor for regulating the Ag@C structure. - Abstract: Ag–carbon composite materials were prepared without any template by hydrothermal carbonization of solvable starch. The composite materials are composed of Ag cores and carbonaceous shell to form a core–shell (Ag@carbon) structure. During the hydrothermal carbonization process, the aromatization and carbonization of solvable starch endowed the Ag@carbon composite structure with abundant aromatic, hydroxyl and carbonyl groups. The AgNO{sub 3} concentration and HTC reaction time are two important factors for regulating the size, morphology and functional groups of the composite material. With the increasing of AgNO{sub 3} concentration, morphologies of the composite material turned from spheres to wires.

  1. Spirally Structured Conductive Composites for Highly Stretchable, Robust Conductors and Sensors.

    Science.gov (United States)

    Wu, Xiaodong; Han, Yangyang; Zhang, Xinxing; Lu, Canhui

    2017-07-12

    Flexible and stretchable electronics are highly desirable for next generation devices. However, stretchability and conductivity are fundamentally difficult to combine for conventional conductive composites, which restricts their widespread applications especially as stretchable electronics. Here, we innovatively develop a new class of highly stretchable and robust conductive composites via a simple and scalable structural approach. Briefly, carbon nanotubes are spray-coated onto a self-adhesive rubber film, followed by rolling up the film completely to create a spirally layered structure within the composites. This unique spirally layered structure breaks the typical trade-off between stretchability and conductivity of traditional conductive composites and, more importantly, restrains the generation and propagation of mechanical microcracks in the conductive layer under strain. Benefiting from such structure-induced advantages, the spirally layered composites exhibit high stretchability and flexibility, good conductive stability, and excellent robustness, enabling the composites to serve as highly stretchable conductors (up to 300% strain), versatile sensors for monitoring both subtle and large human activities, and functional threads for wearable electronics. This novel and efficient methodology provides a new design philosophy for manufacturing not only stretchable conductors and sensors but also other stretchable electronics, such as transistors, generators, artificial muscles, etc.

  2. Comparison of Requirements for Composite Structures for Aircraft and Space Applications

    Science.gov (United States)

    Raju, Ivatury S.; Elliot, Kenny B.; Hampton, Roy W.; Knight, Norman F., Jr.; Aggarwal, Pravin; Engelstad, Stephen P.; Chang, James B.

    2010-01-01

    In this report, the aircraft and space vehicle requirements for composite structures are compared. It is a valuable exercise to study composite structural design approaches used in the airframe industry and to adopt methodology that is applicable for space vehicles. The missions, environments, analysis methods, analysis validation approaches, testing programs, build quantities, inspection, and maintenance procedures used by the airframe industry, in general, are not transferable to spaceflight hardware. Therefore, while the application of composite design approaches from aircraft and other industries is appealing, many aspects cannot be directly utilized. Nevertheless, experiences and research for composite aircraft structures may be of use in unexpected arenas as space exploration technology develops, and so continued technology exchanges are encouraged.

  3. Discrete Material Buckling Optimization of Laminated Composite Structures considering "Worst" Shape Imperfections

    DEFF Research Database (Denmark)

    Henrichsen, Søren Randrup; Lindgaard, Esben; Lund, Erik

    2015-01-01

    Robust design of laminated composite structures is considered in this work. Because laminated composite structures are often thin walled, buckling failure can occur prior to material failure, making it desirable to maximize the buckling load. However, as a structure always contains imperfections...... and “worst” shape imperfection optimizations to design robust composite structures. The approach is demonstrated on an U-profile where the imperfection sensitivity is monitored, and based on the example it can be concluded that robust designs can be obtained....

  4. Local structure, composition, and crystallization mechanism of a model two-phase “composite nanoglass”

    Energy Technology Data Exchange (ETDEWEB)

    Chattopadhyay, Soma; Shibata, Tomohiro [CSRRI-IIT, MRCAT, Sector 10, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Kelly, S. D. [EXAFS Analysis, Bolingbrook, Illinois 60440 (United States); Balasubramanian, M. [Sector 20 XOR, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Srinivasan, S. G.; Du, Jincheng; Banerjee, Rajarshi [Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203-5017 (United States); Ayyub, Pushan, E-mail: pushan@tifr.res.in [Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400005 (India)

    2016-02-14

    We report a detailed study of the local composition and structure of a model, bi-phasic nanoglass with nominal stoichiometry Cu{sub 55}Nb{sub 45}. Three dimensional atom probe data suggest a nanoscale-phase-separated glassy structure having well defined Cu-rich and Nb-rich regions with a characteristic length scale of ≈3 nm. However, extended x-ray absorption fine structure analysis indicates subtle differences in the local environments of Cu and Nb. While the Cu atoms displayed a strong tendency to cluster and negligible structural order beyond the first coordination shell, the Nb atoms had a larger fraction of unlike neighbors (higher chemical order) and a distinctly better-ordered structural environment (higher topological order). This provides the first experimental indication that metallic glass formation may occur due to frustration arising from the competition between chemical ordering and clustering. These observations are complemented by classical as well as ab initio molecular dynamics simulations. Our study indicates that these nanoscale phase-separated glasses are quite distinct from the single phase nanoglasses (studied by Gleiter and others) in the following three respects: (i) they contain at least two structurally and compositionally distinct, nanodispersed, glassy phases, (ii) these phases are separated by comparatively sharp inter-phase boundaries, and (iii) thermally induced crystallization occurs via a complex, multi-step mechanism. Such materials, therefore, appear to constitute a new class of disordered systems that may be called a composite nanoglass.

  5. Phase II CRADA ORNL99-0568 Report : Developing Transmission-Less Inverter Drive Systems for Axial-Gap Permanent magnet Accessory and Traction Motors and Generators; FINAL

    International Nuclear Information System (INIS)

    McKeever, J.W.

    2001-01-01

    Researchers of the Oak Ridge National Laboratory's (ORNLs) Power Electronics and Electric Machine Research Center (PEEMRC) collaborated with Visual Computing Systems (VCS) to develop an electric axial-gap permanent magnet (PM) motor controlled by a self-sensing inverter for driving vehicle accessories such as power steering, air conditioning, and brakes. VCS designed an 8 kW motor based on their Segmented Electromagnetic Array (SEMA) technology. ORNL designed a 10 kW inverter to fit within the volume of a housing, which had been integrated with the motor. This modular design was pursued so that multiple modules could be used for higher power applications. ORNL built the first inverter under the cooperative research and development agreement (CRADA) ORNL 98-0514 and drove a refurbished Delta motor with no load during the Merit Review at ORNL on Monday, May 17, 1999. Inverter circuitry and instructions for assembling the inverters were sent to VCS. A report was prepared and delivered during the Future Car Congress in April 2000, at Arlington, Virginia. Collaboration continued under CRADA ORNL 99-0568 as VCS designed and built a SEMA motor with a dual coil platter to be the traction motor for an electric truck. VCS and ORNL assembled two 45 kW inverters. Each inverter drove one coil, which was designed to deliver 15 kW continuous power and 45 kW peak power for 90 s. The vehicle was road tested as part of the Future Truck Competition. A report was prepared and delivered during the PCIM in October 2000, at Boston, Massachusetts

  6. Design and Manufacturing of Composite Tower Structure for Wind Turbine Equipment

    Science.gov (United States)

    Park, Hyunbum

    2018-02-01

    This study proposes the composite tower design process for large wind turbine equipment. In this work, structural design of tower and analysis using finite element method was performed. After structural design, prototype blade manufacturing and test was performed. The used material is a glass fiber and epoxy resin composite. And also, sand was used in the middle part. The optimized structural design and analysis was performed. The parameter for optimized structural design is weight reduction and safety of structure. Finally, structure of tower will be confirmed by structural test.

  7. Lightning current tests to evaluate vulnerability of electronics in composite structures

    NARCIS (Netherlands)

    Blaj, M.A.; Buesink, Frederik Johannes Karel; Damstra, G.C.; Leferink, Frank Bernardus Johannes

    2010-01-01

    Protecting highly sensitive electronics housed inside composite structures against lightning is a real challenge. The direct strike represents the worst-case scenario for composite structures. The electromagnetic field generated by an indirect lightning strike in the vicinity of highly sensitive

  8. Stiff, Strong Splice For A Composite Sandwich Structure

    Science.gov (United States)

    Schmaling, D.

    1991-01-01

    New type of splice for composite sandwich structure reduces peak shear stress in structure. Layers of alternating fiber orientation interposed between thin ears in adhesive joint. Developed for structural joint in spar of helicopter rotor blade, increases precision of control over thickness of adhesive at joint. Joint easy to make, requires no additional pieces, and adds little weight.

  9. Computational simulation of acoustic fatigue for hot composite structures

    Science.gov (United States)

    Singhal, S. N.; Nagpal, V. K.; Murthy, P. L. N.; Chamis, C. C.

    1991-01-01

    This paper presents predictive methods/codes for computational simulation of acoustic fatigue resistance of hot composite structures subjected to acoustic excitation emanating from an adjacent vibrating component. Select codes developed over the past two decades at the NASA Lewis Research Center are used. The codes include computation of (1) acoustic noise generated from a vibrating component, (2) degradation in material properties of the composite laminate at use temperature, (3) dynamic response of acoustically excited hot multilayered composite structure, (4) degradation in the first-ply strength of the excited structure due to acoustic loading, and (5) acoustic fatigue resistance of the excited structure, including propulsion environment. Effects of the laminate lay-up and environment on the acoustic fatigue life are evaluated. The results show that, by keeping the angled plies on the outer surface of the laminate, a substantial increase in the acoustic fatigue life is obtained. The effect of environment (temperature and moisure) is to relieve the residual stresses leading to an increase in the acoustic fatigue life of the excited panel.

  10. Impact source localisation in aerospace composite structures

    Science.gov (United States)

    De Simone, Mario Emanuele; Ciampa, Francesco; Boccardi, Salvatore; Meo, Michele

    2017-12-01

    The most commonly encountered type of damage in aircraft composite structures is caused by low-velocity impacts due to foreign objects such as hail stones, tool drops and bird strikes. Often these events can cause severe internal material damage that is difficult to detect and may lead to a significant reduction of the structure’s strength and fatigue life. For this reason there is an urgent need to develop structural health monitoring systems able to localise low-velocity impacts in both metallic and composite components as they occur. This article proposes a novel monitoring system for impact localisation in aluminium and composite structures, which is able to determine the impact location in real-time without a-priori knowledge of the mechanical properties of the material. This method relies on an optimal configuration of receiving sensors, which allows linearization of well-known nonlinear systems of equations for the estimation of the impact location. The proposed algorithm is based on the time of arrival identification of the elastic waves generated by the impact source using the Akaike Information Criterion. The proposed approach was demonstrated successfully on both isotropic and orthotropic materials by using a network of closely spaced surface-bonded piezoelectric transducers. The results obtained show the validity of the proposed algorithm, since the impact sources were detected with a high level of accuracy. The proposed impact detection system overcomes current limitations of other methods and can be retrofitted easily on existing aerospace structures allowing timely detection of an impact event.

  11. Numerical analysis of nonlinear behavior of steel-concrete composite structures

    Directory of Open Access Journals (Sweden)

    Í.J.M. LEMES

    Full Text Available Abstract This paper presents the development of an effective numerical formulation for the analysis of steel-concrete composite structures considering geometric and materials nonlinear effects. Thus, a methodology based on Refined Plastic Hinge Method (RPHM was developed and the stiffness parameters were obtained by homogenization of cross-section. The evaluation of structural elements strength is done through the Strain Compatibility Method (SCM. The Newton-Raphson Method with path-following strategies is adopted to solve nonlinear global and local (in cross-section level equations. The results are compared with experimental and numerical database presents in literature and a good accuracy is observed in composite cross sections, composite columns, and composite portal frames.

  12. OOA composite structures applicable in railway industry

    Directory of Open Access Journals (Sweden)

    Rusnáková Soňa

    2017-01-01

    Full Text Available Composite sandwich structures offers several advantages over conventional structural materials such as lightweight, high bending and torsional stiffness, superior thermal insulation and excellent acoustic damping. In the aerospace industry, sandwich composites are commonly manufactured using the autoclave process which is associated with high operating cost. Out-of-autoclave (OOA manufacturing has been shown to be capable of producing low cost and high performance composites. In this paper we present results of experimental testing of various sandwich materials according various standards and actual requirements in transport industry. We compared the different types of surface and paint systems, because these layers are the most important in contact with the surrounding environment and load conditions. In the experimental measurements were used various materials. For the core of the sandwich structure were selected aluminium honeycomb, aramid honeycomb and PET (Polyethylene terephthalate foam core. Support layers were chosen two kinds of predimpregnated materials. The conditions of measurements were requirements for strength and rigidity, safety - flame resistance and reflectivity resistance. The samples were tested at the 3 - point bending test according to standard EN ISO 178, by modified test to determine the force required to rapture threaded insert, by test of reflectivity according to UIC CODE 844-4 R and according to standard EN 45545-2 fire protection of railway vehicles.

  13. Chemical compositions, methods of making the chemical compositions, and structures made from the chemical compositions

    Science.gov (United States)

    Yang, Lei; Cheng, Zhe; Liu, Ze; Liu, Meilin

    2015-01-13

    Embodiments of the present disclosure include chemical compositions, structures, anodes, cathodes, electrolytes for solid oxide fuel cells, solid oxide fuel cells, fuel cells, fuel cell membranes, separation membranes, catalytic membranes, sensors, coatings for electrolytes, electrodes, membranes, and catalysts, and the like, are disclosed.

  14. Evaluation of advanced gas chromatographs for on-site analysis. Final CRADA report for number Y-1295-0374

    Energy Technology Data Exchange (ETDEWEB)

    Wise, M.B.; Guerin, M.R.; Palausky, A.; Merriweather, R. [Lockheed Martin Energy Research, Oak Ridge, TN (United States); Forsberg, R.E. [Mine Safety Appliances-Baseline Industries, Lyons, CO (United States)

    1997-02-21

    The EKHO gas chromatography (GC) is being marketed by Mine Safety Appliances as an instrument for on-site environmental analysis and for process applications. This GC utilizes a unique bundled capillary column produced in Russia that provides very fast analysis and a wide linear dynamic range. Oak Ridge National Laboratory (ORNL) has been involved in a CRADA with Mine Safety Appliances in order to evaluate the analytical performance of the EKHO GC and is suitability for on-site environmental applications. Tests that were performed at ORNL included the analysis of air, water, and soil samples for aromatic hydrocarbons including benzene, toluene, xylene, and ethylbenzene (BTEX). These compounds were selected in order to simulate contamination by gasoline and other petroleum fuels. Performance factors that were studied included the instrument detection limits, the linearity, dynamic range, and precision for replicate samples. Other factors that were evaluated include the ease of set-up and operation.

  15. National Security Science and Technology Initiative: Air Cargo Screening, Final Report for CRADA Number NFE-07-01081

    Energy Technology Data Exchange (ETDEWEB)

    Bingham, Philip [ORNL; Bush, John [Battelle Memorial Institute; Bowerman, Biays [Brookhaven National Laboratory; Cespedes, Ernesto [Idaho National Laboratory; White, Timothy [Pacific Northwest National Laboratory

    2004-12-01

    The non-intrusive inspection (NII) of consolidated air cargo carried on commercial passenger aircraft continues to be a technically challenging, high-priority requirement of the Department of Homeland Security’s Science and Technology Directorate (DHS S&T), the Transportation Security Agency and the Federal Aviation Administration. The goal of deploying a screening system that can reliably and cost-effectively detect explosive threats in consolidated cargo without adversely affecting the flow of commerce will require significant technical advances that will take years to develop. To address this critical National Security need, the Battelle Memorial Institute (Battelle), under a Cooperative Research and Development Agreement (CRADA) with four of its associated US Department of Energy (DOE) National Laboratories (Oak Ridge, Pacific Northwest, Idaho, and Brookhaven), conducted a research and development initiative focused on identifying, evaluating, and integrating technologies for screening consolidated air cargo for the presence of explosive threats. Battelle invested $8.5M of internal research and development funds during fiscal years 2007 through 2009.

  16. Fluid-structure interaction and its effect on the performance of composite structures under air-blast loading

    Directory of Open Access Journals (Sweden)

    E Wang

    2016-09-01

    Full Text Available Three material systems: E-glass Vinyl-Ester (EVE composites, sandwich composites with EVE facesheet and monolithic foam core (2 different core thicknesses, and monolithic aluminum alloy plates, were subjected to shock wave loading to study their blast response and fluid-structure interaction behaviors. High-speed photography systems were utilized to obtain the real-time side-view and back face deformation images. A 3-D Digital Image Correlation (DIC technique was used to analyze the real-time back face displacement fields and subsequently obtain the characteristic fluid-structure interaction time. The reflected pressure profiles and the deflection of the back face center point reveal that the areal density plays an important role in the fluid-structure interaction. The predictions from Taylor's model (classical solution, does not consider the compressibility and model by Wang et al. (considers the compressibility were compared with the experimental results. These results indicated that the model by Wang et al. can predict the experimental results accurately, especially during the characteristic fluid-structure interaction time. Further study revealed that the fluid-structure interaction between the fluid and the sandwich composites cannot be simplified as the fluid-structure interaction between the fluid and the facesheet. Also, it was observed that the core thickness affects the fluid-structure interaction behavior of sandwich composites.

  17. The effects of embedded piezoelectric fiber composite sensors on the structural integrity of glass-fiber–epoxy composite laminate

    International Nuclear Information System (INIS)

    Konka, Hari P; Wahab, M A; Lian, K

    2012-01-01

    Piezoelectric fiber composite sensors (PFCSs) made from micro-sized lead zirconate titanate (PZT) fibers have many advantages over the traditional bulk PZT sensors for embedded sensor applications. PFCSs as embedded sensors will be an ideal choice to continuously monitor the stress/strain levels and health conditions of composite structures. PFCSs are highly flexible, easily embeddable, have high compatibility with composite structures, and also provides manufacturing flexibility. This research is focused on examining the effects of embedding PFCS sensors (macro-fiber composite (MFC) and piezoelectric fiber composite (PFC)) on the structural integrity of glass-fiber–epoxy composite laminates. The strengths of composite materials with embedded PFCSs and conventional PZT sensors were compared, and the advantages of PFCS sensors over PZTs were demonstrated. Initially a numerical simulation study is performed to understand the local stress/strain field near the embedded sensor region inside a composite specimen. High stress concentration regions were observed near the embedded sensor corner edge. Using PFCS leads to a reduction of 56% in longitudinal stress concentration and 38% in transverse stress concentration, when compared to using the conventional PZTs as embedded sensors. In-plane tensile, in-plane tension–tension fatigue, and short beam strength tests are performed to evaluate the strengths/behavior of the composite specimens containing embedded PFCS. From the tensile test it is observed that embedding PFCS and PZT sensors in the composite structures leads to a reduction in ultimate strength by 3 and 6% respectively. From the fatigue test results it is concluded that both embedded PFCS and PZT sensors do not have a significant effect on the fatigue behavior of the composite specimens. From the short beam strength test it is found that embedding PFCS and PZT sensors leads to a reduction in shear strength by 7 and 15% respectively. Overall the pure PZT

  18. The effects of embedded piezoelectric fiber composite sensors on the structural integrity of glass-fiber-epoxy composite laminate

    Science.gov (United States)

    Konka, Hari P.; Wahab, M. A.; Lian, K.

    2012-01-01

    Piezoelectric fiber composite sensors (PFCSs) made from micro-sized lead zirconate titanate (PZT) fibers have many advantages over the traditional bulk PZT sensors for embedded sensor applications. PFCSs as embedded sensors will be an ideal choice to continuously monitor the stress/strain levels and health conditions of composite structures. PFCSs are highly flexible, easily embeddable, have high compatibility with composite structures, and also provides manufacturing flexibility. This research is focused on examining the effects of embedding PFCS sensors (macro-fiber composite (MFC) and piezoelectric fiber composite (PFC)) on the structural integrity of glass-fiber-epoxy composite laminates. The strengths of composite materials with embedded PFCSs and conventional PZT sensors were compared, and the advantages of PFCS sensors over PZTs were demonstrated. Initially a numerical simulation study is performed to understand the local stress/strain field near the embedded sensor region inside a composite specimen. High stress concentration regions were observed near the embedded sensor corner edge. Using PFCS leads to a reduction of 56% in longitudinal stress concentration and 38% in transverse stress concentration, when compared to using the conventional PZTs as embedded sensors. In-plane tensile, in-plane tension-tension fatigue, and short beam strength tests are performed to evaluate the strengths/behavior of the composite specimens containing embedded PFCS. From the tensile test it is observed that embedding PFCS and PZT sensors in the composite structures leads to a reduction in ultimate strength by 3 and 6% respectively. From the fatigue test results it is concluded that both embedded PFCS and PZT sensors do not have a significant effect on the fatigue behavior of the composite specimens. From the short beam strength test it is found that embedding PFCS and PZT sensors leads to a reduction in shear strength by 7 and 15% respectively. Overall the pure PZT sensors

  19. Vegetation composition and structure influences bird species ...

    African Journals Online (AJOL)

    Vegetation composition and structure influences bird species community ... variables on bird species diversity and richness of respective foraging guilds, and ... of the species assessed: (1) increasing closed cover due to woody plant density, ...

  20. 3D flexible NiTi-braided elastomer composites for smart structure applications

    International Nuclear Information System (INIS)

    Heller, L; Vokoun, D; Šittner, P; Finckh, H

    2012-01-01

    While outstanding functional properties of thin NiTi wires are nowadays well recognized and beneficially utilized in medical NiTi devices, development of 2D/3D wire structures made out of these NiTi wires remains challenging and mostly unexplored. The research is driven by the idea of creating novel 2D/3D smart structures which inherit the functional properties of NiTi wires and actively utilize geometrical deformations within the structure to create new/improved functional properties. Generally, textile technology provides attractive processing methods for manufacturing 2D/3D smart structures made out of NiTi wires. Such structures may be beneficially combined with soft elastomers to create smart deformable composites. Following this route, we carried out experimental work focused on development of 3D flexible NiTi-braided elastomer composites involving their design, laboratory manufacture and thermomechanical testing. We describe the manufacturing technology and structural properties of these composites; and perform thermomechanical tests on the composites, focusing particularly on quasistatic tensile properties, energy absorption, damping and actuation under tensile loading. Functional thermomechanical properties of the composites are discussed with regard to the mechanical properties of the components and architecture of the composites. It is found that the composites indeed inherit all important features of the thermomechanical behavior of NiTi wires but, due to their internal architecture, outperform single NiTi wires in some features such as the magnitude of recoverable strain, superelastic damping capacity and thermally induced actuation strain. (paper)

  1. Structure evaluation of cast dispersive AlSi-CrxCy composites

    Directory of Open Access Journals (Sweden)

    M. Cholewa

    2008-08-01

    Full Text Available In this work author showed the diversification of structure for cast dispersive AlSi-CrxCy composites. Wide possibilities of properties control and optimization were described, through microstructure of the matrix and the transition zone shaping. Utility castings were prepared with use of traditional casting techniques, ceramic and metal moulds. The influence of technological conditions and cooling rate ion the composite structure was studied. The main factor of structural changes was the diffusion at matrix – reinforcement interface. Divers structure was observed in particle close neighborhood. Possibilities of diffusion control were indicated through application of factors assisting the crystallization.

  2. Scale Up of Malonic Acid Fermentation Process: Cooperative Research and Development Final Report, CRADA Number CRD-16-612

    Energy Technology Data Exchange (ETDEWEB)

    Schell, Daniel J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-04-16

    The goal of this work is to use the large fermentation vessels in the National Renewable Energy Laboratory's (NREL) Integrated Biorefinery Research Facility (IBRF) to scale-up Lygos' biological-based process for producing malonic acid and to generate performance data. Initially, work at the 1 L scale validated successful transfer of Lygos' fermentation protocols to NREL using a glucose substrate. Outside of the scope of the CRADA with NREL, Lygos tested their process on lignocellulosic sugars produced by NREL at Lawrence Berkeley National Laboratory's (LBNL) Advanced Biofuels Process Development Unit (ABPDU). NREL produced these cellulosic sugar solutions from corn stover using a separate cellulose/hemicellulose process configuration. Finally, NREL performed fermentations using glucose in large fermentors (1,500- and 9,000-L vessels) to intermediate product and to demonstrate successful performance of Lygos' technology at larger scales.

  3. Lightning Protection for Composite Aircraft Structures

    Science.gov (United States)

    Olson, G. O.

    1985-01-01

    Lightning protection system consisting of two layers of aluminum foil separated by layer of dielectric material protects graphite/epoxy composite structures on aircraft. Protective layer is secondarily applied lightning protection system, prime advantage of which is nullification of thermal and right angle effect of lightning arc attachment to graphite/epoxy laminate.

  4. Vegetation structure and floristic composition of Gergeda Anfillo ...

    African Journals Online (AJOL)

    Vegetation structure and floristic composition of Gergeda Anfillo Forest, West Ethiopia. ... Moreover, the forest housed 10 of the 24 national priority tree species and four plant communities were identified by cluster analysis. Structural analysis revealed that the forest is dominated by small sized trees and shrubs.

  5. Universal composition-structure-property maps for natural and biomimetic platelet-matrix composites and stacked heterostructures.

    Science.gov (United States)

    Sakhavand, Navid; Shahsavari, Rouzbeh

    2015-03-16

    Many natural and biomimetic platelet-matrix composites--such as nacre, silk, and clay-polymer-exhibit a remarkable balance of strength, toughness and/or stiffness, which call for a universal measure to quantify this outstanding feature given the structure and material characteristics of the constituents. Analogously, there is an urgent need to quantify the mechanics of emerging electronic and photonic systems such as stacked heterostructures. Here we report the development of a unified framework to construct universal composition-structure-property diagrams that decode the interplay between various geometries and inherent material features in both platelet-matrix composites and stacked heterostructures. We study the effects of elastic and elastic-perfectly plastic matrices, overlap offset ratio and the competing mechanisms of platelet versus matrix failures. Validated by several 3D-printed specimens and a wide range of natural and synthetic materials across scales, the proposed universally valid diagrams have important implications for science-based engineering of numerous platelet-matrix composites and stacked heterostructures.

  6. Recent developments of discrete material optimization of laminated composite structures

    DEFF Research Database (Denmark)

    Lund, Erik; Sørensen, Rene

    2015-01-01

    This work will give a quick summary of recent developments of the Discrete Material Optimization approach for structural optimization of laminated composite structures. This approach can be seen as a multi-material topology optimization approach for selecting the best ply material and number...... of plies in a laminated composite structure. The conceptual combinatorial design problem is relaxed to a continuous problem such that well-established gradient based optimization techniques can be applied, and the optimization problem is solved on basis of interpolation schemes with penalization...

  7. Bioinspired twisted composites based on Bouligand structures

    Science.gov (United States)

    Pinto, F.; Iervolino, O.; Scarselli, G.; Ginzburg, D.; Meo, M.

    2016-04-01

    The coupling between structural support and protection makes biological systems an important source of inspiration for the development of advanced smart composite structures. In particular, some particular material configurations can be implemented into traditional composites in order to improve their impact resistance and the out-of-plane properties, which represents one of the major weakness of commercial carbon fibres reinforced polymers (CFRP) structures. Based on this premise, a three-dimensional twisted arrangement shown in a vast multitude of biological systems (such as the armoured cuticles of Scarabei, the scales of Arapaima Gigas and the smashing club of Odontodactylus Scyllarus) has been replicated to develop an improved structural material characterised by a high level of in-plane isotropy and a higher interfacial strength generated by the smooth stiffness transition between each layer of fibrils. Indeed, due to their intrinsic layered nature, interlaminar stresses are one of the major causes of failure of traditional CFRP and are generated by the mismatch of the elastic properties between plies in a traditional laminate. Since the energy required to open a crack or a delamination between two adjacent plies is due to the difference between their orientations, the gradual angle variation obtained by mimicking the Bouligand Structures could improve energy absorption and the residual properties of carbon laminates when they are subjected to low velocity impact event. Two different bioinspired laminates were manufactured following a double helicoidal approach and a rotational one and were subjected to a complete test campaign including low velocity impact loading and compared to a traditional quasi-isotropic panel. Fractography analysis via X-Ray tomography was used to understand the mechanical behaviour of the different laminates and the residual properties were evaluated via Compression After Impact (CAI) tests. Results confirmed that the biological

  8. Virtual Testing of Composite Structures Made of High Entropy Alloys and Steel

    Directory of Open Access Journals (Sweden)

    Victor Geantă

    2017-11-01

    Full Text Available High entropy alloys (HEA are metallic materials obtained from a mixture of at least five atomic-scale chemical elements. They are characterized by high mechanical strength, good thermal stability and hardenability. AlCrFeCoNi alloys have high compression strength and tensile strength values of 2004 MPa, respectively 1250 MPa and elongation of about 32.7%. These materials can be used to create HEA-steel type composite structures which resist to dynamic deformation during high speed impacts. The paper presents four different composite structures made from a combination of HEA and carbon steel plates, using different joining processes. The numerical simulation of the impact behavior of the composite structures was performed by virtual methods, taking into account the mechanical properties of both materials. For analyzing each constructive variant, three virtual shootings were designed, using a 7.62 × 39 mm cal. incendiary armor-piercing bullet and different impact velocities. The best ballistic behavior was provided by the composite structures obtained by welding and brazing that have good continuity and rigidity. The other composite structures, which do not have good surface adhesion, show high fragmentation risk, because the rear plate can fragment on the axis of shooting due to the combination between the shock waves and the reflected ones. The order of materials in the composite structure has a very important role in decreasing the impact energy.

  9. Polycaprolactone/starch composite: Fabrication, structure, properties, and applications.

    Science.gov (United States)

    Ali Akbari Ghavimi, Soheila; Ebrahimzadeh, Mohammad H; Solati-Hashjin, Mehran; Abu Osman, Noor Azuan

    2015-07-01

    Interests in the use of biodegradable polymers as biomaterials have grown. Among the different polymeric composites currently available, the blend of starch and polycaprolactone (PCL) has received the most attention since the 1980s. Novamont is the first company that manufactured a PCL/starch (SPCL) composite under the trademark Mater-Bi®. The properties of PCL (a synthetic, hydrophobic, flexible, expensive polymer with a low degradation rate) and starch (a natural, hydrophilic, stiff, abundant polymer with a high degradation rate) blends are interesting because of the composite components have completely different structures and characteristics. PCL can adjust humidity sensitivity of starch as a biomaterial; while starch can enhance the low biodegradation rate of PCL. Thus, by appropriate blending, SPCL can overcome important limitations of both PCL and starch components and promote controllable behavior in terms of mechanical properties and degradation which make it suitable for many biomedical applications. This article reviewed the different fabrication and modification methods of the SPCL composite; different properties such as structural, physical, and chemical as well as degradation behavior; and different applications as biomaterials. © 2014 Wiley Periodicals, Inc.

  10. Hybrid Bridge Structures Made of Frp Composite and Concrete

    Science.gov (United States)

    Rajchel, Mateusz; Siwowski, Tomasz

    2017-09-01

    Despite many advantages over the conventional construction materials, the contemporary development of FRP composites in bridge engineering is limited due to high initial cost, low stiffness (in case of glass fibers) and sudden composite failure mode. In order to reduce the given limitations, mixed (hybrid) solutions connecting the FRP composites and conventional construction materials, including concrete, have been tested in many countries for 20 years. Shaping the hybrid structures based on the attributes of particular materials, aims to increase stiffness and reduce cost without losing the carrying capacity, lightness and easiness of bridges that includes such hybrid girders, and to avoid the sudden dangerous failure mode. In the following article, the authors described examples of hybrid road bridges made of FRP composite and concrete within the time of 20 years and presented the first Polish hybrid FRP-concrete road bridge. Also, the directions of further research, necessary to spread these innovative, advanced and sustainable bridge structures were indicated.

  11. A structural model for composite rotor blades and lifting surfaces

    Science.gov (United States)

    Rehfield, Lawrence W.; Atilgan, Ali R.

    1987-01-01

    Composite material systems are currently candidates for aerospace structures, primarily for the design flexibiity they offer i.e., it is possible to tailor the material and manufacturing approach to the application. Two notable examples are the wing of the Grumman/USAF/DARPA X-29 and rotor blades under development by the U.S.A. Aerostructures Directorate (AVSCOM), Langley Research Center. A working definition of elastic or structural tailoring is the use of structural concept, fiber orientation, ply stacking sequence, and a blend of materials to achieve specific performance goals. In the design process, choices of materials and dimensions are made which produce specific response characteristics which permit the selected goals to be achieved. Common choices for tailoring goals are preventing instabilities or vibration resonances or enhancing damage tolerance. An essential, enabling factor in the design of tailored composite structures is structural modeling that accurately, but simply, characterizes response. The objective of this paper is to improve the single-cell beam model for composite rotor blades or lifting surfaces and to demonstrate its usefullness in applications.

  12. Improved Fabrication of Ceramic Matrix Composite/Foam Core Integrated Structures

    Science.gov (United States)

    Hurwitz, Frances I.

    2009-01-01

    The use of hybridized carbon/silicon carbide (C/SiC) fabric to reinforce ceramic matrix composite face sheets and the integration of such face sheets with a foam core creates a sandwich structure capable of withstanding high-heatflux environments (150 W/cm2) in which the core provides a temperature drop of 1,000 C between the surface and the back face without cracking or delamination of the structure. The composite face sheet exhibits a bilinear response, which results from the SiC matrix not being cracked on fabrication. In addition, the structure exhibits damage tolerance under impact with projectiles, showing no penetration to the back face sheet. These attributes make the composite ideal for leading edge structures and control surfaces in aerospace vehicles, as well as for acreage thermal protection systems and in high-temperature, lightweight stiffened structures. By tailoring the coefficient of thermal expansion (CTE) of a carbon fiber containing ceramic matrix composite (CMC) face sheet to match that of a ceramic foam core, the face sheet and the core can be integrally fabricated without any delamination. Carbon and SiC are woven together in the reinforcing fabric. Integral densification of the CMC and the foam core is accomplished with chemical vapor deposition, eliminating the need for bond-line adhesive. This means there is no need to separately fabricate the core and the face sheet, or to bond the two elements together, risking edge delamination during use. Fibers of two or more types are woven together on a loom. The carbon and ceramic fibers are pulled into the same pick location during the weaving process. Tow spacing may be varied to accommodate the increased volume of the combined fiber tows while maintaining a target fiber volume fraction in the composite. Foam pore size, strut thickness, and ratio of face sheet to core thickness can be used to tailor thermal and mechanical properties. The anticipated CTE for the hybridized composite is managed by

  13. Nano-structured polymer composites and process for preparing same

    Science.gov (United States)

    Hillmyer, Marc; Chen, Liang

    2013-04-16

    A process for preparing a polymer composite that includes reacting (a) a multi-functional monomer and (b) a block copolymer comprising (i) a first block and (ii) a second block that includes a functional group capable of reacting with the multi-functional monomer, to form a crosslinked, nano-structured, bi-continuous composite. The composite includes a continuous matrix phase and a second continuous phase comprising the first block of the block copolymer.

  14. Novel fabrication techniques for low-mass composite structures in silicon particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, Neal, E-mail: neal.hartman@cern.ch; Silber, Joseph; Anderssen, Eric; Garcia-Sciveres, Maurice; Gilchriese, Murdock; Johnson, Thomas; Cepeda, Mario

    2013-12-21

    The structural design of silicon-based particle detectors is governed by competing demands of reducing mass while maximizing stability and accuracy. These demands can only be met by fiber reinforced composite laminates (CFRP). As detecting sensors and electronics become lower mass, the motivation to reduce structure as a proportion of overall mass pushes modern detector structures to the lower limits of composite ply thickness, while demanding maximum stiffness. However, classical approaches to composite laminate design require symmetric laminates and flat structures, in order to minimize warping during fabrication. This constraint of symmetry in laminate design, and a “flat plate” approach to fabrication, results in more massive structures. This study presents an approach to fabricating stable and accurate, geometrically complex composite structures by bonding warped, asymmetric, but ultra-thin component laminates together in an accurate tool, achieving final overall precision normally associated with planar structures. This technique has been used to fabricate a prototype “I-beam” that supports two layers of detecting elements, while being up to 20 times stiffer and up to 30% lower mass than comparable, independent planar structures (typically known as “staves”)

  15. Multiphase composite coatings: structure and properties

    International Nuclear Information System (INIS)

    Yurov, V M; Guchenko, S A; Platonova, E S; Syzdykova, A Sh; Lysenko, E N

    2015-01-01

    The paper discusses the results of the research into the formation of ion-plasma multiphase coatings. The types of the formed structures are found to be not so diverse, as those formed, for example, in alloy crystallization. The structures observed are basically of globular type and, more rarely, of unclosed dissipative and cellular structures. It is shown that the properties of the coating formed in deposition are largely determined by its surface energy or surface tension. Since the magnitude of the surface tension (surface energy) in most cases is an additive quantity, each of the elements of the coating composition contributes to the total surface energy. In case of simultaneous sputtering of multiphase cathodes, high entropy coatings with an ordered cellular structure and improved mechanical properties are formed. (paper)

  16. High frequency characterization of conductive inks embedded within a structural composite

    Science.gov (United States)

    Pa, Peter; McCauley, Raymond; Larimore, Zachary; Mills, Matthew; Yarlaggada, Shridhar; Mirotznik, Mark S.

    2015-06-01

    Woven fabric composites provide an attractive platform for integrating electromagnetic functionality—such as conformal load-bearing antennas and frequency selective surfaces—into a structural platform. One practical fabrication method for integrating conductive elements within a woven fabric composite system involves using additive manufacturing systems such as screen printing. While screen printing is an inherently scalable, flexible and cost effective method, little is known about the high frequency electrical properties of its conductive inks when they are embedded within the woven fabric composite. Thus, we have completed numerical and experimental studies to determine the electrical conductivity of screen printable conductive inks that are embedded within this composite. We have also performed mechanical studies to evaluate how printing affects the structural performance of the composite.

  17. Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, volume 1

    Science.gov (United States)

    Soderquist, Joseph R. (Compiler); Neri, Lawrence M. (Compiler); Bohon, Herman L. (Compiler)

    1992-01-01

    This publication contains the proceedings of the Ninth DOD/NASA/FAA conference on Fibrous Composites in structural Design. Presentations were made in the following areas of composite structural design: perspectives in composites; design methodology; design applications; design criteria; supporting technology; damage tolerance; and manufacturing.

  18. Structural and functional characterization of barium zirconium titanate / epoxy composites

    Directory of Open Access Journals (Sweden)

    Filiberto González Garcia

    2011-12-01

    Full Text Available The dielectric behavior of composite materials (barium zirconium titanate / epoxy system was analyzed as a function of ceramic concentration. Structure and morphologic behavior of the composites was investigated by X-ray Diffraction (XRD, Fourier transformed infrared spectroscopy (FT-IR, Raman spectroscopy, field emission scanning electron microscopy (FE-SEM and transmission electron microscopy (TEM analyses. Composites were prepared by mixing the components and pouring them into suitable moulds. It was demonstrated that the amount of inorganic phase affects the morphology of the presented composites. XRD revealed the presence of a single phase while Raman scattering confirmed structural transitions as a function of ceramic concentration. Changes in the ceramic concentration affected Raman modes and the distribution of particles along into in epoxy matrix. Dielectric permittivity and dielectric losses were influenced by filler concentration.

  19. Structure-property-processing correlations in freeze-cast composite scaffolds.

    Science.gov (United States)

    Hunger, Philipp M; Donius, Amalie E; Wegst, Ulrike G K

    2013-05-01

    Surprisingly few reports have been published, to date, on the structure-property-processing correlations observed in freeze-cast materials directionally solidified from polymer solutions, or ceramic or metal slurries. The studies that exist focus on properties of sintered ceramics, that is materials whose structure was altered by further processing. In this contribution, we report first results on correlations observed in alumina-chitosan-gelatin composites, which were chosen as a model system to test and compare the effect of particle size and processing parameters on their mechanical properties at a specific composition. Our study reveals that highly porous (>90%) hybrid materials can be manufactured by freeze casting, through the self-assembly of a polymer and a ceramic phase that occurs during directional solidification, without the need of additional processing steps such as sintering or infiltration. It further illustrates that the properties of freeze-cast hybrid materials can independently be tailored at two levels of their structural hierarchy, allowing for the simultaneous optimization of both mechanical and structural requirements. An increase in freezing rate resulted in decreases in lamellar spacing, cell wall thickness, pore aspect ratio and cross-sectional area, as well as increases in both Young's modulus and compressive yield strength. The mechanical properties of the composite scaffolds increased with an increasing particle size. The results show that both structure and mechanical properties of the freeze-cast composites can be custom-designed and that they are thus ideally suited for a large variety of applications that require high porosity at low or medium load-bearing capacity. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  20. Composition-structure-property relation of oxide glasses

    DEFF Research Database (Denmark)

    Hermansen, Christian

    also increases such properties. Yet, these rules are not strictly followed even for the simplest binary oxide glasses, such as alkali silicates, borates and phosphates. In this thesis it is argued that the missing link between composition and properties is the glass structure. Structural models...... are proposed based on topological selection rules and experimentally verified. The relation between structure and properties is evaluated using topological constraint theory, which in its essence is a theory that quantifies the two intuitions of the glass scientist. The end result is a quantitative model...

  1. Self-learning health monitoring algorithm in composite structures

    Science.gov (United States)

    Grassia, Luigi; Iannone, Michele; Califano, America; D'Amore, Alberto

    2018-02-01

    The paper describes a system that it is able of monitoring the health state of a composite structure in real time. The hardware of the system consists of a wire of strain sensors connected to a control unit. The software of the system elaborates the strain data and in real time is able to detect the presence of an eventual damage of the structures monitored with the strain sensors. The algorithm requires as input only the strains of the monitored structured measured on real time, i.e. those strains coming from the deformations of the composite structure due to the working loads. The health monitoring system does not require any additional device to interrogate the structure as often used in the literature, instead it is based on a self-learning procedure. The strain data acquired when the structure is healthy are used to set up the correlations between the strain in different positions of structure by means of neural network. Once the correlations between the strains in different position have been set up, these correlations act as a fingerprint of the healthy structure. In case of damage the correlation between the strains in the position of the structure near the damage will change due to the change of the stiffness of the structure caused by the damage. The developed software is able to recognize the change of the transfer function between the strains and consequently is able to detect the damage.

  2. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications

    Directory of Open Access Journals (Sweden)

    Raffaella Di Sante

    2015-07-01

    Full Text Available In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques.

  3. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications

    Science.gov (United States)

    Di Sante, Raffaella

    2015-01-01

    In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques. PMID:26263987

  4. A critical review of nanotechnologies for composite aerospace structures

    Science.gov (United States)

    Kostopoulos, Vassilis; Masouras, Athanasios; Baltopoulos, Athanasios; Vavouliotis, Antonios; Sotiriadis, George; Pambaguian, Laurent

    2017-03-01

    The past decade extensive efforts have been invested in understanding the nano-scale and revealing the capabilities offered by nanotechnology products to structural materials. Integration of nano-particles into fiber composites concludes to multi-scale reinforced composites and has opened a new wide range of multi-functional materials in industry. In this direction, a variety of carbon based nano-fillers has been proposed and employed, individually or in combination in hybrid forms, to approach the desired performance. Nevertheless, a major issue faced lately more seriously due to the interest of industry is on how to incorporate these nano-species into the final composite structure through existing manufacturing processes and infrastructure. This interest originates from several industrial applications needs that request the development of new multi-functional materials which combine enhanced mechanical, electrical and thermal properties. In this work, an attempt is performed to review the most representative processes and related performances reported in literature and the experience obtained on nano-enabling technologies of fiber composite materials. This review focuses on the two main composite manufacturing technologies used by the aerospace industry; Prepreg/Autoclave and Resin Transfer technologies. It addresses several approaches for nano-enabling of composites for these two routes and reports latest achieved results focusing on performance of nano-enabled fiber reinforced composites extracted from literature. Finally, this review work identifies the gap between available nano-technology integration routes and the established industrial composite manufacturing techniques and the challenges to increase the Technology Readiness Level to reach the demands for aerospace industry applications.

  5. Centralized Cryptographic Key Management and Critical Risk Assessment - CRADA Final Report For CRADA Number NFE-11-03562

    Energy Technology Data Exchange (ETDEWEB)

    Abercrombie, R. K. [ORNL; Peters, Scott [Sypris Electronics, LLC

    2014-05-28

    The Department of Energy Office of Electricity Delivery and Energy Reliability (DOE-OE) Cyber Security for Energy Delivery Systems (CSEDS) industry led program (DE-FOA-0000359) entitled "Innovation for Increasing Cyber Security for Energy Delivery Systems (12CSEDS)," awarded a contract to Sypris Electronics LLC to develop a Cryptographic Key Management System for the smart grid (Scalable Key Management Solutions for Critical Infrastructure Protection). Oak Ridge National Laboratory (ORNL) and Sypris Electronics, LLC as a result of that award entered into a CRADA (NFE-11-03562) between ORNL and Sypris Electronics, LLC. ORNL provided its Cyber Security Econometrics System (CSES) as a tool to be modified and used as a metric to address risks and vulnerabilities in the management of cryptographic keys within the Advanced Metering Infrastructure (AMI) domain of the electric sector. ORNL concentrated our analysis on the AMI domain of which the National Electric Sector Cyber security Organization Resource (NESCOR) Working Group 1 (WG1) has documented 29 failure scenarios. The computational infrastructure of this metric involves system stakeholders, security requirements, system components and security threats. To compute this metric, we estimated the stakes that each stakeholder associates with each security requirement, as well as stochastic matrices that represent the probability of a threat to cause a component failure and the probability of a component failure to cause a security requirement violation. We applied this model to estimate the security of the AMI, by leveraging the recently established National Institute of Standards and Technology Interagency Report (NISTIR) 7628 guidelines for smart grid security and the International Electrotechnical Commission (IEC) 63351, Part 9 to identify the life cycle for cryptographic key management, resulting in a vector that assigned to each stakeholder an estimate of their average loss in terms of dollars per day of system

  6. Composite Structure Modeling and Analysis of Advanced Aircraft Fuselage Concepts

    Science.gov (United States)

    Mukhopadhyay, Vivek; Sorokach, Michael R.

    2015-01-01

    NASA Environmentally Responsible Aviation (ERA) project and the Boeing Company are collabrating to advance the unitized damage arresting composite airframe technology with application to the Hybrid-Wing-Body (HWB) aircraft. The testing of a HWB fuselage section with Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) construction is presently being conducted at NASA Langley. Based on lessons learned from previous HWB structural design studies, improved finite-element models (FEM) of the HWB multi-bay and bulkhead assembly are developed to evaluate the performance of the PRSEUS construction. In order to assess the comparative weight reduction benefits of the PRSEUS technology, conventional cylindrical skin-stringer-frame models of a cylindrical and a double-bubble section fuselage concepts are developed. Stress analysis with design cabin-pressure load and scenario based case studies are conducted for design improvement in each case. Alternate analysis with stitched composite hat-stringers and C-frames are also presented, in addition to the foam-core sandwich frame and pultruded rod-stringer construction. The FEM structural stress, strain and weights are computed and compared for relative weight/strength benefit assessment. The structural analysis and specific weight comparison of these stitched composite advanced aircraft fuselage concepts demonstrated that the pressurized HWB fuselage section assembly can be structurally as efficient as the conventional cylindrical fuselage section with composite stringer-frame and PRSEUS construction, and significantly better than the conventional aluminum construction and the double-bubble section concept.

  7. Development of a General-Purpose Analysis System Based on a Programmable Fluid Processor Final Report CRADA No. TC-2027-01

    Energy Technology Data Exchange (ETDEWEB)

    McConaghy, C. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gascoyne, P. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-28

    The purpose ofthis project was to develop a general-purpose analysis system based on a programmable fluid processor (PFP). The PFP is an array of electrodes surrounded by fluid reservoirs and injectors. Injected droplets of various reagents are manjpulated and combined on the array by Dielectrophoretic (DEP) forces. The goal was to create a small handheld device that could accomplish the tasks currently undertaken by much larger, time consuming, manual manipulation in the lab. The entire effo1t was funded by DARPA under the Bio-Flips program. MD Anderson Cancer Center was the PI for the DARPA effort. The Bio-Flips program was a 3- year program that ran from September 2000 to September 2003. The CRADA was somewhat behind the Bi-Flips program running from June 2001 to June 2004 with a no cost extension to September 2004.

  8. Innovative Structural Materials and Sections with Strain Hardening Cementitious Composites

    Science.gov (United States)

    Dey, Vikram

    The motivation of this work is based on development of new construction products with strain hardening cementitious composites (SHCC) geared towards sustainable residential applications. The proposed research has three main objectives: automation of existing manufacturing systems for SHCC laminates; multi-level characterization of mechanical properties of fiber, matrix, interface and composites phases using servo-hydraulic and digital image correlation techniques. Structural behavior of these systems were predicted using ductility based design procedures using classical laminate theory and structural mechanics. SHCC sections are made up of thin sections of matrix with Portland cement based binder and fine aggregates impregnating continuous one-dimensional fibers in individual or bundle form or two/three dimensional woven, bonded or knitted textiles. Traditional fiber reinforced concrete (FRC) use random dispersed chopped fibers in the matrix at a low volume fractions, typically 1-2% to avoid to avoid fiber agglomeration and balling. In conventional FRC, fracture localization occurs immediately after the first crack, resulting in only minor improvement in toughness and tensile strength. However in SHCC systems, distribution of cracking throughout the specimen is facilitated by the fiber bridging mechanism. Influence of material properties of yarn, composition, geometry and weave patterns of textile in the behavior of laminated SHCC skin composites were investigated. Contribution of the cementitious matrix in the early age and long-term performance of laminated composites was studied with supplementary cementitious materials such as fly ash, silica fume, and wollastonite. A closed form model with classical laminate theory and ply discount method, coupled with a damage evolution model was utilized to simulate the non-linear tensile response of these composite materials. A constitutive material model developed earlier in the group was utilized to characterize and

  9. Activation and micropore structure determination of activated carbon-fiber composites

    Energy Technology Data Exchange (ETDEWEB)

    Jagtoyen, M.; Derbyshire, F.; Kimber, G. [Univ. of Kentucky, Lexington, KY (United States). Center for Applied Energy Research

    1997-09-05

    Rigid, high surface area activated carbon fiber composites have been produced with high permeabilities for environmental applications in gas and water purification. These novel monolithic adsorbents can be produced in single pieces to a given size and shape. The project involves a collaboration between the Oak Ridge National Laboratory (ORNL) and the Center for Applied Energy Research (CAER), University of Kentucky. The carbon fiber composites are produced at the ORNL and activated at the CAER using different methods, with the aims of producing a uniform degree of activation, and of closely controlling pore structure and adsorptive properties. The main focus of the present work has been to find a satisfactory means to uniformly activate large samples of carbon fiber composites and produce controlled pore structures. Several environmental applications have been explored for the activated carbon fiber composites. One of these was to evaluate the activated composites for the separation of CH{sub 4}-CO{sub 2} mixtures, and an apparatus was constructed specifically for this purpose. The composites were further evaluated in the cyclic recovery of volatile organics. The activated carbon fiber composites have also been tested for possible water treatment applications by studying the adsorption of sodium pentachlorophenolate, PCP.

  10. Structural dynamics of shroudless, hollow fan blades with composite in-lays

    Science.gov (United States)

    Aiello, R. A.; Hirschbein, M. S.; Chamis, C. C.

    1982-01-01

    Structural and dynamic analyses are presented for a shroudless, hollow titanium fan blade proposed for future use in aircraft turbine engines. The blade was modeled and analyzed using the composite blade structural analysis computer program (COBSTRAN); an integrated program consisting of mesh generators, composite mechanics codes, NASTRAN, and pre- and post-processors. Vibration and impact analyses are presented. The vibration analysis was conducted with COBSTRAN. Results show the effect of the centrifugal force field on frequencies, twist, and blade camber. Bird impact analysis was performed with the multi-mode blade impact computer program. This program uses the geometric model and modal analysis from the COBSTRAN vibration analysis to determine the gross impact response of the fan blades to bird strikes. The structural performance of this blade is also compared to a blade of similar design but with composite in-lays on the outer surface. Results show that the composite in-lays can be selected (designed) to substantially modify the mechanical performance of the shroudless, hollow fan blade.

  11. Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Soderquist, J.R.; Neri, L.M.; Bohon, H.L.

    1992-09-01

    This publication contains the proceedings of the Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design held at Lake Tahoe, Nevada, during 4-7 Nov. 1991. Presentations were made in the following areas of composite structural design: perspectives in composites, design methodology, design applications, design criteria, supporting technology, damage tolerance, and manufacturing.

  12. Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, volume 3

    Science.gov (United States)

    Soderquist, Joseph R. (Compiler); Neri, Lawrence M. (Compiler); Bohon, Herman L. (Compiler)

    1992-01-01

    This publication contains the proceedings of the Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design held at Lake Tahoe, Nevada, during 4-7 Nov. 1991. Presentations were made in the following areas of composite structural design: perspectives in composites, design methodology, design applications, design criteria, supporting technology, damage tolerance, and manufacturing.

  13. Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, volume 2

    Science.gov (United States)

    Soderquist, Joseph R. (Compiler); Neri, Lawrence M. (Compiler); Bohon, Herman L. (Compiler)

    1992-01-01

    This publication contains the proceedings of the Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design held at Lake Tahoe, Nevada, during 4-7 Nov. 1991. Presentations were made in the following areas of composite structural design: perspectives in composites, design methodology, design applications, design criteria, supporting technology, damage tolerance, and manufacturing.

  14. Optimization of SMA layers in composite structures to enhance damping

    Science.gov (United States)

    Haghdoust, P.; Cinquemani, S.; Lecis, N.; Bassani, P.

    2016-04-01

    The performance of lightweight structures can be severely affected by vibration. New design concepts leading to lightweight, slender structural components can increase the vulnerability of the components to failure due to excessive vibration. The intelligent approach to address the problem would be the use of materials which are more capable in dissipating the energy due to their high value of loss factor. Among the different materials available to achieve damping, much attention has been attached to the use of shape memory alloys (SMAs) because of their unique microstructure, leading to good damping capacity. This work describes the design and optimization of a hybrid layered composite structure for the passive suppression of flexural vibrations in slender and light structures. Embedding the SMA layers in composite structure allows to combine different properties: the lightness of the base composite (e.g. fiber glass), the mechanical strength of the insert of metallic material and the relevant damping properties of SMA, in the martensitic phase. In particular, we put our attention on embedding the CuZnAl in the form of thin sheet in a layered composite made by glass fiber reinforced epoxy. By appropriately positioning of the SMA sheets so that they are subjected to the maximum curvature, the damping of the hybrid system can be considerably enhanced. Accordingly analytical method for evaluating the energy dissipation of the thin sheets with different shapes and patterns is developed and is followed by a shape optimization based on genetic algorithm. Eventually different configurations of the hybrid beam structure with different patterns of SMA layer are proposed and compared in the term of damping capacity.

  15. Coplanar capacitance sensors for detecting water intrusion in composite structures

    International Nuclear Information System (INIS)

    Nassr, Amr A; El-Dakhakhni, Wael W; Ahmed, Wael H

    2008-01-01

    Composite materials are becoming more affordable and widely used for retrofitting, rehabilitating and repairing reinforced concrete structures designed and constructed under older specifications. However, the mechanical properties and long-term durability of composite materials may degrade severely in the presence of water intrusion. This study presents a new non-destructive evaluation (NDE) technique for detecting the water intrusion in composite structures by evaluating the dielectric properties of different composite system constituent materials. The variation in the dielectric signatures was employed to design a coplanar capacitance sensor with high sensitivity to detect such defects. An analytical model was used to study the effect of the sensor geometry on the output signal and to optimize sensor design. A finite element model was developed to validate analytical results and to evaluate other sensor design-related parameters. Experimental testing of a concrete specimen wrapped with composite laminate and containing a series of pre-induced water intrusion defects was conducted in order to validate the concept of the new technique. Experimental data showed excellent agreement with the finite element model predictions and confirmed sensor performance

  16. DEVELOPMENT AND VALIDATION OF NUMERICAL METHOD FOR STRENGTH ANALYSIS OF LATTICE COMPOSITE FUSELAGE STRUCTURES

    Directory of Open Access Journals (Sweden)

    2016-01-01

    Full Text Available Lattice composite fuselage structures are developed as an alternative to conventional composite structures based on laminated skin and stiffeners. Structure layout of lattice structures allows to realize advantages of current composite materials to a maximal extent, at the same time minimizing their main shortcomings, that allows to provide higher weight efficiency for these structures in comparison with conventional analogues.Development and creation of lattice composite structures requires development of novel methods of strength anal- ysis, as conventional methods, as a rule, are aiming to strength analysis of thin-walled elements and do not allow to get confident estimation of local strength of high-loaded unidirectional composite ribs.In the present work the method of operative strength analysis of lattice composite structure is presented, based onspecialized FE-models of unidirectional composite ribs and their intersections. In the frames of the method, every rib is modeled by a caisson structure, consisting of arbitrary number of flanges and webs, modeled by membrane finite elements. Parameters of flanges and webs are calculated automatically from the condition of stiffness characteristics equality of real rib and the model. This method allows to perform local strength analysis of high-loaded ribs of lattice structure without use of here-dimensional finite elements, that allows to shorten time of calculations and sufficiently simplify the procedure of analysis of results of calculations.For validation of the suggested method, the results of experimental investigations of full-scale prototype of shell of lattice composite fuselage section have been used. The prototype of the lattice section was manufactured in CRISM and tested in TsAGI within the frames of a number of Russian and International scientific projects. The results of validation have shown that the suggested method allows to provide high operability of strength analysis, keeping

  17. Impact damage response of natural stitched single lap-joint in composite structures

    International Nuclear Information System (INIS)

    Ghasemnejad, H.; Argentiero, Y.; Tez, T.A.; Barrington, P.E.

    2013-01-01

    Highlights: • To study the impact resistance of single lap-joints in composite structures. • To improve the impact resistance of stitched single lap joints using natural Flax yarn. • To investigate the effect of stitching on the damage process of composite materials. • To develop FE techniques to model the impact process of composite structures using LSDYNA. - Abstract: In this paper the damage behaviour of natural stitched composite single lap-joints are investigated under low velocity impact loading conditions. For this study, the laminated hybrid composite beams were pinned using Flax yarns before curing process. The Charpy impact test was chosen to study the energy absorbing capability of single lap composite joints. Composite beams were fabricated from combination of glass/epoxy and carbon/epoxy composites. It was shown that composite beams which are stitched through the thickness are able to absorb more energy in comparison with adhesive bonded composite joints in the hybrid composite beams. The Charpy impact test of stitched composite single lap joint was also simulated by finite element analysis using software LS-DYNA and the results verified with relevant experimental data

  18. Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Soderquist, J.R.; Neri, L.M.; Bohon, H.L.

    1992-09-01

    This publication contains the proceedings of the Ninth DOD/NASA/FAA conference on Fibrous Composites in structural Design. Presentations were made in the following areas of composite structural design: perspectives in composites; design methodology; design applications; design criteria; supporting technology; damage tolerance; and manufacturing. Separate abstracts have been indexed into the database for articles from this report.

  19. Kinetics of radiation-induced structural alterations in electron-irradiated polymer-based composites

    International Nuclear Information System (INIS)

    Zaikin, Yu.A.; Potanin, A.S.; Koztaeva, U.P.

    2002-01-01

    Complete text of publication follows. In our previous studies measurements of internal friction temperature dependence were used for characterization of thermally activated and radiation-induced structural evolution in different types of polymer-based composites. This paper supplements these measurements with kinetic studies of internal friction (IF) parameters and EPR signals in a glass-cloth epoxy-filled laminate ST-ETF after electron irradiation up to doses of 1-10 MGy. Experiment have shown that the lifetime of free radicals in this composite considerably exceeds the characteristic time of molecular structural rearrangement due to scission and cross-linking after irradiation, as determined from IF measurements. This result is explained by slow proceeding of sterically hindered disproportionation reactions that stabilize the end groups of the macro-chain disrupt during irradiation and finally fix the act of scission. A mathematical model is formulated for description of structural evolution and alterations of IF parameters in polymer-based composites during and after electron irradiation. The description is based on the track model of radiation damage in polymers and phenomenological theory of radiation-induced structural transformations. General description does not give details of radiation-chemical conversion in different structural components of composites but indicates the direction of their structural evolution. In the model considered a composite material was divided into three parts (binder, filler, and a boundary layer). It was supposed that after primary distribution of radiation energy radiation-chemical conversion proceeds independently in each of these regions. It was also suggested that all the radical reactions were of the second order. On the example of glass-cloth laminate ST-ETF it is shown that this model allows to describe alterations in composite structural characteristics during irradiation and in the course of their self-organization after

  20. Health Monitoring of Composite Material Structures using a Vibrometry Technique

    Science.gov (United States)

    Schulz, Mark J.

    1997-01-01

    Large composite material structures such as aircraft and Reusable Launch Vehicles (RLVS) operate in severe environments comprised of vehicle dynamic loads, aerodynamic loads, engine vibration, foreign object impact, lightning strikes, corrosion, and moisture absorption. These structures are susceptible to damage such as delamination, fiber breaking/pullout, matrix cracking, and hygrothermal strain. To ensure human safety and load-bearing integrity, these structures must be inspected to detect and locate often invisible damage and faults before becoming catastrophic. Moreover, nearly all future structures will need some type of in-service inspection technique to increase their useful life and reduce maintenance and overall costs. Possible techniques for monitoring the health and indicating damage on composite structures include: c-scan, thermography, acoustic emissions using piezoceramic actuators or fiber-optic wires with gratings, laser ultrasound, shearography, holography, x-ray, and others. These techniques have limitations in detecting damage that is beneath the surface of the structure, far away from a sensor location, or during operation of the vehicle. The objective of this project is to develop a more global method for damage detection that is based on structural dynamics principles, and can inspect for damage when the structure is subjected to vibratory loads to expose faults that may not be evident by static inspection. A Transmittance Function Monitoring (TFM) method is being developed in this project for ground-based inspection and operational health monitoring of large composite structures as a RLV. A comparison of the features of existing health monitoring approaches and the proposed TFM method is given.

  1. Composite Structural Motifs of Binding Sites for Delineating Biological Functions of Proteins

    Science.gov (United States)

    Kinjo, Akira R.; Nakamura, Haruki

    2012-01-01

    Most biological processes are described as a series of interactions between proteins and other molecules, and interactions are in turn described in terms of atomic structures. To annotate protein functions as sets of interaction states at atomic resolution, and thereby to better understand the relation between protein interactions and biological functions, we conducted exhaustive all-against-all atomic structure comparisons of all known binding sites for ligands including small molecules, proteins and nucleic acids, and identified recurring elementary motifs. By integrating the elementary motifs associated with each subunit, we defined composite motifs that represent context-dependent combinations of elementary motifs. It is demonstrated that function similarity can be better inferred from composite motif similarity compared to the similarity of protein sequences or of individual binding sites. By integrating the composite motifs associated with each protein function, we define meta-composite motifs each of which is regarded as a time-independent diagrammatic representation of a biological process. It is shown that meta-composite motifs provide richer annotations of biological processes than sequence clusters. The present results serve as a basis for bridging atomic structures to higher-order biological phenomena by classification and integration of binding site structures. PMID:22347478

  2. Heterogeneous dissipative composite structures

    Science.gov (United States)

    Ryabov, Victor; Yartsev, Boris; Parshina, Ludmila

    2018-05-01

    The paper suggests mathematical models of decaying vibrations in layered anisotropic plates and orthotropic rods based on Hamilton variation principle, first-order shear deformation laminated plate theory (FSDT), as well as on the viscous-elastic correspondence principle of the linear viscoelasticity theory. In the description of the physical relationships between the materials of the layers forming stiff polymeric composites, the effect of vibration frequency and ambient temperature is assumed as negligible, whereas for the viscous-elastic polymer layer, temperature-frequency relationship of elastic dissipation and stiffness properties is considered by means of the experimentally determined generalized curves. Mitigation of Hamilton functional makes it possible to describe decaying vibration of anisotropic structures by an algebraic problem of complex eigenvalues. The system of algebraic equation is generated through Ritz method using Legendre polynomials as coordinate functions. First, real solutions are found. To find complex natural frequencies of the system, the obtained real natural frequencies are taken as input values, and then, by means of the 3rd order iteration method, complex natural frequencies are calculated. The paper provides convergence estimates for the numerical procedures. Reliability of the obtained results is confirmed by a good correlation between analytical and experimental values of natural frequencies and loss factors in the lower vibration tones for the two series of unsupported orthotropic rods formed by stiff GRP and CRP layers and a viscoelastic polymer layer. Analysis of the numerical test data has shown the dissipation & stiffness properties of heterogeneous composite plates and rods to considerably depend on relative thickness of the viscoelastic polymer layer, orientation of stiff composite layers, vibration frequency and ambient temperature.

  3. Oxidation resistance coating for niobium base structural composites

    International Nuclear Information System (INIS)

    Tabaru, T.; Shobu, K.; Kim, J.H.; Hirai, H.; Hanada, S.

    2003-01-01

    Oxidation behavior of Al-rich Mo(Si,Al) 2 base alloys, which is a candidate material for the oxidation resistance coating on Nb base structural composites, were investigated by thermogravimetry. The Mo(Si,Al) 2 base alloys containing Mo 5 (Si,Al) 3 up to about 10 vol% exhibits excellent oxidation resistance at temperatures ranging from 780 to 1580 K, particularly at 1580 K due to continuous Al 2 O 3 layer development. To evaluate the applicability of the Mo(Si,Al) 2 base coating, plasma spraying on Nb base composites were undertaken. However, interface reaction layer was found to form during the following heat treatment. Preparation of Mo(Si,Al) 2 /Al 2 O 3 /Nb layered structures via powder metallurgical process was attempted to preclude diffusion reaction between coating and substrate. (orig.)

  4. Multi-physics damage sensing in nano-engineered structural composites

    International Nuclear Information System (INIS)

    De Villoria, Roberto Guzman; Yamamoto, Namiko; Miravete, Antonio; Wardle, Brian L

    2011-01-01

    Non-destructive evaluation techniques can offer viable diagnostic and prognostic routes to mitigating failures in engineered structures such as bridges, buildings and vehicles. However, existing techniques have significant drawbacks, including poor spatial resolution and limited in situ capabilities. We report here a novel approach where structural advanced composites containing electrically conductive aligned carbon nanotubes (CNTs) are ohmically heated via simple electrical contacts, and damage is visualized via thermographic imaging. Damage, in the form of cracks and other discontinuities, usefully increases resistance to both electrical and thermal transport in these materials, which enables tomographic full-field damage assessment in many cases. Characteristics of the technique include the ability for real-time measurement of the damage state during loading, low-power operation (e.g. 15 deg. C rise at 1 W), and beyond state-of-the-art spatial resolution for sensing damage in composites. The enhanced thermographic technique is a novel and practical approach for in situ monitoring to ascertain structural health and to prevent structural failures in engineered structures such as aerospace and automotive vehicles and wind turbine blades, among others.

  5. Methodology for repeated load analysis of composite structures with embedded magnetic microwires

    Directory of Open Access Journals (Sweden)

    K. Semrád

    2017-01-01

    Full Text Available The article processes issue of strength of cyclically loaded composite structures with the possibility of contactless stress measuring inside a material. For this purpose a contactless tensile stress sensor using improved induction principle based on the magnetic microwires embedded in the composite structure has been developed. The methodology based on the E-N approach was applied for the analysis of the repeated load of the wing hinge connection, including finite element method (FEM fatigue strength analysis. The results proved that composites in comparison with the metal structures offer significant weight reduction of the small aircraft construction, whereas the required strength, stability and lifetime of the components are remained.

  6. Activation and micropore structure of carbon-fiber composites

    Energy Technology Data Exchange (ETDEWEB)

    Jagtoyen, M.; Derbyshire, F.; Kimber, G. [Univ. of Kentucky, Lexington, KY (United States). Center for Applied Energy Research

    1997-12-01

    Rigid, high surface area activated carbon fiber composites have been produced with high permeabilities for environmental applications in gas and water purification. The project involves a collaboration between the Oak Ridge National Laboratory (ORNL) and the Center for Applied Energy Research (CAER), University of Kentucky. The main focus of recent work has been to find a satisfactory means to uniformly activate large samples of carbon fiber composites to produce controlled pore structures. Processes have been developed using activation in steam and CO{sub 2}, and a less conventional method involving oxygen chemisorption and subsequent heat treatment. Another objective has been to explore applications for the activated composites in environmental applications related to fossil energy production.

  7. Durability-Based Design Criteria for a Chopped-Glass-Fiber Automotive Structural Composite; TOPICAL

    International Nuclear Information System (INIS)

    Battiste, R.L.; Corum, J.M.; Ren, W.; Ruggles, M.B.

    1999-01-01

    This report provides recommended durability-based design criteria for a chopped-glass-fiber reinforced polymeric composite for automotive structural applications. The criteria closely follow the framework of an earlier criteria document for a continuous-strand-mat (CSM) glass-fiber reference composite. Together these design criteria demonstrate a framework that can be adapted for future random-glass-fiber composites for automotive structural applications

  8. Structure and properties of compositions based on petroleum sulfonic acids

    Energy Technology Data Exchange (ETDEWEB)

    Tutorskii, I.A.; Sultanova, A.S.; Belkina, E.V.; Fomin, A.G. [Lomonosov Academy of Fine Chemical Technology, Moscow (Russian Federation)

    1995-03-01

    Colloidal characteristics of compositions based on petroleum sulfonic acids were studied. Neutralized heavy oil residue exhibits surface-active properties and contains an ultradisperse filler. Analysis of the compositions by size-exclusion-chromatography shows deep structural changes in the heavy acid residue upon neutralization with calcium carbonate.

  9. Versatile Micromechanics Model for Multiscale Analysis of Composite Structures

    Science.gov (United States)

    Kwon, Y. W.; Park, M. S.

    2013-08-01

    A general-purpose micromechanics model was developed so that the model could be applied to various composite materials such as reinforced by particles, long fibers and short fibers as well as those containing micro voids. Additionally, the model can be used with hierarchical composite materials. The micromechanics model can be used to compute effective material properties like elastic moduli, shear moduli, Poisson's ratios, and coefficients of thermal expansion for the various composite materials. The model can also calculate the strains and stresses at the constituent material level such as fibers, particles, and whiskers from the composite level stresses and strains. The model was implemented into ABAQUS using the UMAT option for multiscale analysis. An extensive set of examples are presented to demonstrate the reliability and accuracy of the developed micromechanics model for different kinds of composite materials. Another set of examples is provided to study the multiscale analysis of composite structures.

  10. Structures and Performance of Graphene/Polyimide Composite Graphite Fibers

    Directory of Open Access Journals (Sweden)

    LI Na

    2017-09-01

    Full Text Available Dry-wet spinning process was used to gain graphene oxide/polyimide composite fibers, then graphene/polyimide composite carbon and graphite fibers were obtained through carbonized and graphitized. Different graphene oxide contents of the composite carbon and graphite fibers were measured by thermal gravimetric analysis, Raman, mechanical properties, electrical properties,SEM and so on. The results show that when the GO content is 0.3%(mass fraction,the same below, the thermal property of the graphene oxide/polyimide composite fibers is the best. The mechanical and electrical properties are obriously improved by the addition of GO, graphitization degree also increases. When the composite carbon fibers are treated at 2800℃, GO content increases to 2.0%, the thermal conductivity of the composite graphite fibers reaches 435.57W·m-1·K-1 and cross-section structures of carbon fibers are more compact.

  11. Composites as structural materials in fusion reactors

    International Nuclear Information System (INIS)

    Megusar, J.

    1989-01-01

    In fusion reactors, materials are used under extreme conditions of temperature, stress, irradiation, and chemical environment. The absence of adequate materials will seriously impede the development of fusion reactors and might ultimately be one of the major difficulties. Some of the current materials problems can be solved by proper design features. For others, the solution will have to rely on materials development. A parallel and balanced effort between the research in plasma physics and fusion-related technology and in materials research is, therefore, the best strategy to ultimately achieve economic, safe, and environmentally acceptable fusion. The essential steps in developing composites for structural components of fusion reactors include optimization of mechanical properties followed by testing under fusion-reactor-relevant conditions. In optimizing the mechanical behavior of composite materials, a wealth of experience can be drawn from the research on ceramic matrix and metal matrix composite materials sponsored by the Department of Defense. The particular aspects of this research relevant to fusion materials development are methodology of the composite materials design and studies of new processing routes to develop composite materials with specific properties. Most notable examples are the synthesis of fibers, coatings, and ceramic materials in their final shapes form polymeric precursors and the infiltration of fibrous preforms by molten metals

  12. Cooled Ceramic Matrix Composite Propulsion Structures Demonstrated

    Science.gov (United States)

    Jaskowiak, Martha H.; Dickens, Kevin W.

    2005-01-01

    NASA's Next Generation Launch Technology (NGLT) Program has successfully demonstrated cooled ceramic matrix composite (CMC) technology in a scramjet engine test. This demonstration represented the world s largest cooled nonmetallic matrix composite panel fabricated for a scramjet engine and the first cooled nonmetallic composite to be tested in a scramjet facility. Lightweight, high-temperature, actively cooled structures have been identified as a key technology for enabling reliable and low-cost space access. Tradeoff studies have shown this to be the case for a variety of launch platforms, including rockets and hypersonic cruise vehicles. Actively cooled carbon and CMC structures may meet high-performance goals at significantly lower weight, while improving safety by operating with a higher margin between the design temperature and material upper-use temperature. Studies have shown that using actively cooled CMCs can reduce the weight of the cooled flow-path component from 4.5 to 1.6 lb/sq ft and the weight of the propulsion system s cooled surface area by more than 50 percent. This weight savings enables advanced concepts, increased payload, and increased range. The ability of the cooled CMC flow-path components to operate over 1000 F hotter than the state-of-the-art metallic concept adds system design flexibility to space-access vehicle concepts. Other potential system-level benefits include smaller fuel pumps, lower part count, lower cost, and increased operating margin.

  13. Permeability and flammability study of composite sandwich structures for cryogenic applications

    Science.gov (United States)

    Bubacz, Monika

    Fiber reinforced plastics offer advantageous specific strength and stiffness compared to metals and has been identified as candidates for the reusable space transportation systems primary structures including cryogenic tanks. A number of carbon and aramid fiber reinforced plastics have been considered for the liquid hydrogen tanks. Materials selection is based upon mechanical properties and containment performance (long and short term) and upon manufacturing considerations. The liquid hydrogen tank carries shear, torque, end load, and bending moment due to gusts, maneuver, take-off, landing, lift, drag, and fuel sloshing. The tank is pressurized to about 1.5 atmosphere (14.6psi or 0.1 MPa) differential pressure and on ascent maintains the liquid hydrogen at a temperature of 20K. The objective of the research effort into lay the foundation for developing the technology required for reliable prediction of the effects of various design, manufacturing, and service parameters on the susceptibility of composite tanks to develop excessive permeability to cryogenic fuels. Efforts will be expended on developing the materials and structural concepts for the cryogenic tanks that can meet the functional requirements. This will include consideration for double wall composite sandwich structures, with inner wall to meet the cryogenic requirements. The structure will incorporate nanoparticles for properties modifications and developing barriers. The main effort will be extended to tank wall's internal skin design. The main requirements for internal composite stack are: (1) introduction of barrier film (e.g. honeycomb material paper sheet) to reduce the wall permeability to hydrogen, (2) introduction of nanoparticles into laminate resin to prevent micro-cracking or crack propagation. There is a need to characterize and analyze composite sandwich structural damage due to burning and explosion. Better understanding of the flammability and blast resistance of the composite structures

  14. SnO2/ZnO composite structure for the lithium-ion battery electrode

    International Nuclear Information System (INIS)

    Ahmad, Mashkoor; Yingying, Shi; Sun, Hongyu; Shen, Wanci; Zhu, Jing

    2012-01-01

    In this article, SnO 2 /ZnO composite structures have been synthesized by two steps hydrothermal method and investigated their lithium storage capacity as compared with pure ZnO. It has been found that these composite structures combining the large specific surface area, stability and catalytic activity of SnO 2 micro-crystals, demonstrate the higher initial discharge capacity of 1540 mA h g −1 with a Coulombic efficiency of 68% at a rate of 120 mA h g −1 between 0.02 and 2 V and found much better than that of any previously reported ZnO based composite anodes. In addition, a significantly enhanced cycling performance, i.e., a reversible capacity of 497 mA h g −1 is retained after 40 cycles. The improved lithium storage capacity and cycle life is attributed to the addition of SnO 2 structure, which act as good electronic conductors and better accommodation of the large volume change during lithiation/delithiation process. - Graphical abstract: SnO 2 /ZnO composite structures demonstrate the improved lithium storage capacity and cycle life as compared with pure ZnO nanostructure. Highlights: ► Synthesis of SnO 2 /ZnO composite structures by two steps hydrothermal approach. ► Investigation of lithium storage capacity. ► Excellent lithium storage capacity and cycle life of SnO 2 /ZnO composite structures.

  15. Method for reinforcing threads in multilayer composite tubes and cylindrical structures

    International Nuclear Information System (INIS)

    Romanoski, G.R.; Burchell, T.D.

    1996-01-01

    Multilayer techniques such as: tape wrapping, braiding, and filament winding represent versatile and economical routes for fabricating composite tubes and cylindrical structures. However, multilayer architectures lack the radial reinforcement required to retain threads when the desired means of connection or closure is a threaded joint. This issue was addressed in the development of a filament wound, carbon-carbon composite impact shell for the NASA radioisotope thermoelectric generator. The problem of poor thread shear strength was solved by incorporating a number of radial elements of triangular geometry around the circumference of the thread for the full length of thread engagement. The radial elements significantly increased the shear strength of the threaded joint by transmitting the applied force to the balance of composite structure. This approach is also applicable to ceramic composites

  16. Structural and compositional features of high-rise buildings: experimental design in Yekaterinburg

    Science.gov (United States)

    Yankovskaya, Yulia; Lobanov, Yuriy; Temnov, Vladimir

    2018-03-01

    The study looks at the specifics of high-rise development in Yekaterinburg. High-rise buildings are considered in the context of their historical development, structural features, compositional and imaginative design techniques. Experience of Yekaterinburg architects in experimental design is considered and analyzed. Main issues and prospects of high-rise development within the Yekaterinburg structure are studied. The most interesting and significant conceptual approaches to the structural and compositional arrangement of high-rise buildings are discussed.

  17. Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, volume 3

    Energy Technology Data Exchange (ETDEWEB)

    Soderquist, J.R.; Neri, L.M.; Bohon, H.L.

    1992-09-01

    This publication contains the proceedings of the Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design held at Lake Tahoe, Nevada, during 4-7 Nov. 1991. Presentations were made in the following areas of composite structural design: perspectives in composites, design methodology, design applications, design criteria, supporting technology, damage tolerance, and manufacturing. Separate abstracts have been prepared for articles from this report.

  18. Sapphire/TiAl composites - structure and properties

    International Nuclear Information System (INIS)

    Povarova, K.B.; Antonova, A.V.; Mileiko, S.T.; Sarkissyan, N.S.

    2001-01-01

    Ti-Al-intermetallic-based alloys with lamellar microstructure, -γ(TiAl) +α 2 (Ti 3 Al) are characterized by a high melting point of 1460 o C, a low density of ∼3.9 g/cm 3 , a high gas corrosion resistance up to a temperature of about 900 o C, a high creep resistance up to a temperature of about 800 o C, and a sufficiently high fracture toughness at low temperatures, up to 30 Mpa x m 1/2 . Hence, they are considered as excellent matrices for fibres of high melting point. Unlike well-developed SiC/TiAl composites, which have an obvious upper limit for the usage temperature due to SiC/TiAl interaction, Sapphire/TiAl composites remain nearly unknown because fibres to be used in such composites have not been really available. At the present time, such fibres are developed in Solid State Physics Inst. of RAS. The results of preliminary creep tests of Al 2 O 3 /TiAl composites obtained by using pressure casting have shown that usage of such composite systems shifts the temperature limit for light structural materials in terms of creep resistance to, at least, 1050 o C: creep strength on 100 h time base reaches 120 MPa at that temperature. It occurs also that Sapphire-fibres/TiAl-matrix composite specimens have an increased gas corrosion resistance by more than one order of the magnitudes as compared with that of the matrix alloy. (author)

  19. A novel method for a multi-level hierarchical composite with brick-and-mortar structure.

    Science.gov (United States)

    Brandt, Kristina; Wolff, Michael F H; Salikov, Vitalij; Heinrich, Stefan; Schneider, Gerold A

    2013-01-01

    The fascination for hierarchically structured hard tissues such as enamel or nacre arises from their unique structure-properties-relationship. During the last decades this numerously motivated the synthesis of composites, mimicking the brick-and-mortar structure of nacre. However, there is still a lack in synthetic engineering materials displaying a true hierarchical structure. Here, we present a novel multi-step processing route for anisotropic 2-level hierarchical composites by combining different coating techniques on different length scales. It comprises polymer-encapsulated ceramic particles as building blocks for the first level, followed by spouted bed spray granulation for a second level, and finally directional hot pressing to anisotropically consolidate the composite. The microstructure achieved reveals a brick-and-mortar hierarchical structure with distinct, however not yet optimized mechanical properties on each level. It opens up a completely new processing route for the synthesis of multi-level hierarchically structured composites, giving prospects to multi-functional structure-properties relationships.

  20. A novel method for a multi-level hierarchical composite with brick-and-mortar structure

    Science.gov (United States)

    Brandt, Kristina; Wolff, Michael F. H.; Salikov, Vitalij; Heinrich, Stefan; Schneider, Gerold A.

    2013-07-01

    The fascination for hierarchically structured hard tissues such as enamel or nacre arises from their unique structure-properties-relationship. During the last decades this numerously motivated the synthesis of composites, mimicking the brick-and-mortar structure of nacre. However, there is still a lack in synthetic engineering materials displaying a true hierarchical structure. Here, we present a novel multi-step processing route for anisotropic 2-level hierarchical composites by combining different coating techniques on different length scales. It comprises polymer-encapsulated ceramic particles as building blocks for the first level, followed by spouted bed spray granulation for a second level, and finally directional hot pressing to anisotropically consolidate the composite. The microstructure achieved reveals a brick-and-mortar hierarchical structure with distinct, however not yet optimized mechanical properties on each level. It opens up a completely new processing route for the synthesis of multi-level hierarchically structured composites, giving prospects to multi-functional structure-properties relationships.

  1. Zirconia-hydroxyapatite composite material with micro porous structure.

    Science.gov (United States)

    Matsumoto, Takuya Junior; An, Sang-Hyun; Ishimoto, Takuya; Nakano, Takayoshi; Matsumoto, Takuya; Imazato, Satoshi

    2011-11-01

    Titanium plates and apatite blocks are commonly used for restoring large osseous defects in dental and orthopedic surgery. However, several cases of allergies against titanium have been recently reported. Also, sintered apatite block does not possess sufficient mechanical strength. In this study, we attempted to fabricate a composite material that has mechanical properties similar to biocortical bone and high bioaffinity by compounding hydroxyapatite (HAp) with the base material zirconia (ZrO(2)), which possesses high mechanical properties and low toxicity toward living organisms. After mixing the raw material powders at several different ZrO(2)/HAp mixing ratios, the material was compressed in a metal mold (8 mm in diameter) at 5 MPa. Subsequently, it was sintered for 5 h at 1500°C to obtain the ZrO(2)/HAp composite. The mechanical property and biocompatibility of materials were investigated. Furthermore, osteoconductivity of materials was investigated by animal studies. A composite material with a minute porous structure was successfully created using ZrO(2)/HAp powders, having different particle sizes, as the starting material. The material also showed high protein adsorption and a favorable cellular affinity. When the mixing ratio was ZrO(2)/HAp=70/30, the strength was equal to cortical bone. Furthermore, in vivo experiments confirmed its high osteoconductivity. The composite material had strength similar to biocortical bones with high cell and tissue affinities by compounding ZrO(2) and HAp. The ZrO(2)/HAp composite material having micro porous structure would be a promising bone restorative material. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  2. Application of Ultrasonic Phased Array Technology to the Detection of Defect in Composite Stiffened-structures

    Science.gov (United States)

    Zhou, Yuan-Qi; Zhan, Li-Hua

    2016-05-01

    Composite stiffened-structure consists of the skin and stringer has been widely used in aircraft fuselage and wings. The main purpose of the article is to detect the composite material reinforced structure accurately and explore the relationship between defect formation and structural elements or curing process. Based on ultrasonic phased array inspection technology, the regularity of defects in the manufacture of composite materials are obtained, the correlation model between actual defects and nondestructive testing are established. The article find that the forming quality of deltoid area in T-stiffened structure is obviously improved by pre-curing, the defects of hat-stiffened structure are affected by the mandrel. The results show that the ultrasonic phased array inspection technology can be an effectively way for the detection of composite stiffened-structures, which become an important means to control the defects of composite and improve the quality of the product.

  3. Application of the self-diagnosis composite into concrete structure

    Science.gov (United States)

    Matsubara, Hideaki; Shin, Soon-Gi; Okuhara, Yoshiki; Nomura, Hiroshi; Yanagida, Hiroaki

    2001-04-01

    The function and performance of the self-diagnosis composites embedded in mortar/concrete blocks and concrete piles were investigated by bending tests and electrical resistance measurements. Carbon powder (CP) and carbon fiber (CF) were introduced in glass fiber reinforced plastics composites to obtain electrical conductivity. The CP composite has commonly good performances in various bending tests of block and pile specimens, comparing to the CF composite. The electrical resistance of the CP composite increases in a small strain to response remarkably micro-crack formation at about 200 (mu) strain and to detect well to smaller deformations before the crack formation. The CP composite possesses a continuous resistance change up to a large strain level near the final fracture of concrete structures reinforced by steel bars. The cyclic bending tests showed that the micro crack closed at unloading state was able to be evaluated from the measurement of residual resistance. It has been concluded that the self- diagnosis composite is fairly useful for the measurement of damage and fracture in concrete blocks and piles.

  4. Structural Framework for Flight: NASA's Role in Development of Advanced Composite Materials for Aircraft and Space Structures

    Science.gov (United States)

    Tenney, Darrel R.; Davis, John G., Jr.; Johnston, Norman J.; Pipes, R. Byron; McGuire, Jack F.

    2011-01-01

    This serves as a source of collated information on Composite Research over the past four decades at NASA Langley Research Center, and is a key reference for readers wishing to grasp the underlying principles and challenges associated with developing and applying advanced composite materials to new aerospace vehicle concepts. Second, it identifies the major obstacles encountered in developing and applying composites on advanced flight vehicles, as well as lessons learned in overcoming these obstacles. Third, it points out current barriers and challenges to further application of composites on future vehicles. This is extremely valuable for steering research in the future, when new breakthroughs in materials or processing science may eliminate/minimize some of the barriers that have traditionally blocked the expanded application of composite to new structural or revolutionary vehicle concepts. Finally, a review of past work and identification of future challenges will hopefully inspire new research opportunities and development of revolutionary materials and structural concepts to revolutionize future flight vehicles.

  5. Fabrication, polarization, and characterization of PVDF matrix composites for integrated structural load sensing

    International Nuclear Information System (INIS)

    Haghiashtiani, Ghazaleh; Greminger, Michael A

    2015-01-01

    The focus of this work is to evaluate a new carbon fiber reinforced composite structure with integrated sensing capabilities. In this composite structure, the typical matrix material used for carbon fiber reinforced composites is replaced with the thermoplastic polyvinylidene difluoride (PVDF). Since PVDF has piezoelectric properties, it enables the structure to be used for integrated load sensing. In addition, the electrical conductivity property of the carbon fabric is harnessed to form the electrodes of the integrated sensor. In order to prevent the carbon fiber electrodes from shorting to each other, a thin Kevlar fabric layer is placed between the two carbon fiber electrode layers as a dielectric. The optimal polarization parameters were determined using a design of experiments approach. Once polarized, the samples were then used in compression and tensile tests to determine the effective d 33 and d 31 piezoelectric coefficients. The degree of polarization of the PVDF material was determined by relating the effective d 33 coefficient of the composite to the achieved d 33 of the PVDF component of the composite using a closed form expression. Using this approach, it was shown that optimal polarization of the composite material results in a PVDF component d 33 of 3.2 pC N −1 . Moreover, the Young’s modulus of the composite structure has been characterized. (paper)

  6. Challenges and Opportunities for Nanotechnology in Multi-Functional Composite Structures (Preprint)

    National Research Council Canada - National Science Library

    Baur, Jeff; Silverman, Edward

    2006-01-01

    .... Of the wide variety of structural applications, fiber-reinforced composites for aerospace structures have some of the most demanding applications with extreme requirements in physical, chemical...

  7. Natural Kenaf Fiber Reinforced Composites as Engineered Structural Materials

    Science.gov (United States)

    Dittenber, David B.

    The objective of this work was to provide a comprehensive evaluation of natural fiber reinforced polymer (NFRP)'s ability to act as a structural material. As a chemical treatment, aligned kenaf fibers were treated with sodium hydroxide (alkalization) in different concentrations and durations and then manufactured into kenaf fiber / vinyl ester composite plates. Single fiber tensile properties and composite flexural properties, both in dry and saturated environments, were assessed. Based on ASTM standard testing, a comparison of flexural, tensile, compressive, and shear mechanical properties was also made between an untreated kenaf fiber reinforced composite, a chemically treated kenaf fiber reinforced composite, a glass fiber reinforced composite, and oriented strand board (OSB). The mechanical properties were evaluated for dry samples, samples immersed in water for 50 hours, and samples immersed in water until saturation (~2700 hours). Since NFRPs are more vulnerable to environmental effects than synthetic fiber composites, a series of weathering and environmental tests were conducted on the kenaf fiber composites. The environmental conditions studied include real-time outdoor weathering, elevated temperatures, immersion in different pH solutions, and UV exposure. In all of these tests, degradation was found to be more pronounced in the NFRPs than in the glass FRPs; however, in nearly every case the degradation was less than 50% of the flexural strength or stiffness. Using a method of overlapping and meshing discontinuous fiber ends, large mats of fiber bundles were manufactured into composite facesheets for structural insulated panels (SIPs). The polyisocyanurate foam cores proved to be poorly matched to the strength and stiffness of the NFRP facesheets, leading to premature core shear or delamination failures in both flexure and compressive testing. The NFRPs were found to match well with the theoretical stiffness prediction methods of classical lamination

  8. Critical joints in large composite aircraft structure

    Science.gov (United States)

    Nelson, W. D.; Bunin, B. L.; Hart-Smith, L. J.

    1983-01-01

    A program was conducted at Douglas Aircraft Company to develop the technology for critical structural joints of composite wing structure that meets design requirements for a 1990 commercial transport aircraft. The prime objective of the program was to demonstrate the ability to reliably predict the strength of large bolted composite joints. Ancillary testing of 180 specimens generated data on strength and load-deflection characteristics which provided input to the joint analysis. Load-sharing between fasteners in multirow bolted joints was computed by the nonlinear analysis program A4EJ. This program was used to predict strengths of 20 additional large subcomponents representing strips from a wing root chordwise splice. In most cases, the predictions were accurate to within a few percent of the test results. In some cases, the observed mode of failure was different than anticipated. The highlight of the subcomponent testing was the consistent ability to achieve gross-section failure strains close to 0.005. That represents a considerable improvement over the state of the art.

  9. Concurrent Probabilistic Simulation of High Temperature Composite Structural Response

    Science.gov (United States)

    Abdi, Frank

    1996-01-01

    A computational structural/material analysis and design tool which would meet industry's future demand for expedience and reduced cost is presented. This unique software 'GENOA' is dedicated to parallel and high speed analysis to perform probabilistic evaluation of high temperature composite response of aerospace systems. The development is based on detailed integration and modification of diverse fields of specialized analysis techniques and mathematical models to combine their latest innovative capabilities into a commercially viable software package. The technique is specifically designed to exploit the availability of processors to perform computationally intense probabilistic analysis assessing uncertainties in structural reliability analysis and composite micromechanics. The primary objectives which were achieved in performing the development were: (1) Utilization of the power of parallel processing and static/dynamic load balancing optimization to make the complex simulation of structure, material and processing of high temperature composite affordable; (2) Computational integration and synchronization of probabilistic mathematics, structural/material mechanics and parallel computing; (3) Implementation of an innovative multi-level domain decomposition technique to identify the inherent parallelism, and increasing convergence rates through high- and low-level processor assignment; (4) Creating the framework for Portable Paralleled architecture for the machine independent Multi Instruction Multi Data, (MIMD), Single Instruction Multi Data (SIMD), hybrid and distributed workstation type of computers; and (5) Market evaluation. The results of Phase-2 effort provides a good basis for continuation and warrants Phase-3 government, and industry partnership.

  10. FIBER-TEX 1991: The Fifth Conference on Advanced Engineering Fibers and Textile Structures for Composites

    International Nuclear Information System (INIS)

    Buckley, J.D.

    1992-10-01

    This document is a compilation of papers presented at a joint NASA/North Carolina State University/DoD/Clemson University/Drexel University conference on Fibers, Textile Technology, and Composites Structures held at the College of Textiles Building on Centennial Campus of North Carolina State University, Raleigh, North Carolina on October 15-17, 1991. Conference papers presented information on advanced engineering fibers, textile processes and structures, structural fabric production, mechanics and characteristics of woven composites, pultruded composites, and the latest requirements for the use of textiles in the production of composite materials and structures. Separate abstracts have been prepared for papers in this report

  11. Identification of damage in composite structures using Gaussian mixture model-processed Lamb waves

    Science.gov (United States)

    Wang, Qiang; Ma, Shuxian; Yue, Dong

    2018-04-01

    Composite materials have comprehensively better properties than traditional materials, and therefore have been more and more widely used, especially because of its higher strength-weight ratio. However, the damage of composite structures is usually varied and complicated. In order to ensure the security of these structures, it is necessary to monitor and distinguish the structural damage in a timely manner. Lamb wave-based structural health monitoring (SHM) has been proved to be effective in online structural damage detection and evaluation; furthermore, the characteristic parameters of the multi-mode Lamb wave varies in response to different types of damage in the composite material. This paper studies the damage identification approach for composite structures using the Lamb wave and the Gaussian mixture model (GMM). The algorithm and principle of the GMM, and the parameter estimation, is introduced. Multi-statistical characteristic parameters of the excited Lamb waves are extracted, and the parameter space with reduced dimensions is adopted by principal component analysis (PCA). The damage identification system using the GMM is then established through training. Experiments on a glass fiber-reinforced epoxy composite laminate plate are conducted to verify the feasibility of the proposed approach in terms of damage classification. The experimental results show that different types of damage can be identified according to the value of the likelihood function of the GMM.

  12. Development of on-line condition monitoring system in aerospace structures using advanced composite materials

    International Nuclear Information System (INIS)

    Khan, Z.M.

    2005-01-01

    This research aims to develop condition monitoring systems for advanced aerospace composite structures. To perform these functions successfully a smart system is required that could autonomously respond to environmental changes. The integrated structure senses the environments, conveys the message to central processing unit and reacts instantaneously to external stimuli. Such structures not only monitor their own health but also for warn about onset of failures, fatigue and impending disasters. This required development of methods for embedding optical fibers in composite panels for sensing given defect. The thick and cylindrical composite structures have layer waviness due to fiber microbend defect. Such kind of defect is characteristically hard to detect. It leads to delamination, cracking and deterioration of mechanical properties. The experimental investigation revealed correlation of the intensity of light with the microbend defect in composite structure. (author)

  13. Laminated Ti-Al composites: Processing, structure and strength

    DEFF Research Database (Denmark)

    Du, Yan; Fan, Guohua; Yu, Tianbo

    2016-01-01

    Laminated Ti-Al composite sheets with different layer thickness ratios have been fabricated through hot pressing followed by multi-pass hot rolling at 500 °C.The laminated sheets show strong bonding with intermetallic interface layers of nanoscale thickness between the layers of Ti and Al....... The mechanical properties of the composites with different volume fractions of Al from 10% to 67% show a good combination of strength and ductility. A constraint strain in the hot-rolled laminated structure between the hard and soft phases introduces an elastic-plastic deformation stage, which becomes more...

  14. Integration of fluidic jet actuators in composite structures

    Science.gov (United States)

    Schueller, Martin; Lipowski, Mathias; Schirmer, Eckart; Walther, Marco; Otto, Thomas; Geßner, Thomas; Kroll, Lothar

    2015-04-01

    Fluidic Actuated Flow Control (FAFC) has been introduced as a technology that influences the boundary layer by actively blowing air through slots or holes in the aircraft skin or wind turbine rotor blade. Modern wing structures are or will be manufactured using composite materials. In these state of the art systems, AFC actuators are integrated in a hybrid approach. The new idea is to directly integrate the active fluidic elements (such as SJAs and PJAs) and their components in the structure of the airfoil. Consequently, the integration of such fluidic devices must fit the manufacturing process and the material properties of the composite structure. The challenge is to integrate temperature-sensitive active elements and to realize fluidic cavities at the same time. The transducer elements will be provided for the manufacturing steps using roll-to-roll processes. The fluidic parts of the actuators will be manufactured using the MuCell® process that provides on the one hand the defined reproduction of the fluidic structures and, on the other hand, a high light weight index. Based on the first design concept, a demonstrator was developed in order to proof the design approach. The output velocity on the exit was measured using a hot-wire anemometer.

  15. A Study of Flexible Composites for Expandable Space Structures

    Science.gov (United States)

    Scotti, Stephen J.

    2016-01-01

    Payload volume for launch vehicles is a critical constraint that impacts spacecraft design. Deployment mechanisms, such as those used for solar arrays and antennas, are approaches that have successfully accommodated this constraint, however, providing pressurized volumes that can be packaged compactly at launch and expanded in space is still a challenge. One approach that has been under development for many years is to utilize softgoods - woven fabric for straps, cloth, and with appropriate coatings, bladders - to provide this expandable pressure vessel capability. The mechanics of woven structure is complicated by a response that is nonlinear and often nonrepeatable due to the discrete nature of the woven fiber architecture. This complexity reduces engineering confidence to reliably design and certify these structures, which increases costs due to increased requirements for system testing. The present study explores flexible composite materials systems as an alternative to the heritage softgoods approach. Materials were obtained from vendors who utilize flexible composites for non-aerospace products to determine some initial physical and mechanical properties of the materials. Uniaxial mechanical testing was performed to obtain the stress-strain response of the flexible composites and the failure behavior. A failure criterion was developed from the data, and a space habitat application was used to provide an estimate of the relative performance of flexible composites compared to the heritage softgoods approach. Initial results are promising with a 25% mass savings estimated for the flexible composite solution.

  16. Three-Axis Distributed Fiber Optic Strain Measurement in 3D Woven Composite Structures

    Science.gov (United States)

    Castellucci, Matt; Klute, Sandra; Lally, Evan M.; Froggatt, Mark E.; Lowry, David

    2013-01-01

    Recent advancements in composite materials technologies have broken further from traditional designs and require advanced instrumentation and analysis capabilities. Success or failure is highly dependent on design analysis and manufacturing processes. By monitoring smart structures throughout manufacturing and service life, residual and operational stresses can be assessed and structural integrity maintained. Composite smart structures can be manufactured by integrating fiber optic sensors into existing composite materials processes such as ply layup, filament winding and three-dimensional weaving. In this work optical fiber was integrated into 3D woven composite parts at a commercial woven products manufacturing facility. The fiber was then used to monitor the structures during a VARTM manufacturing process, and subsequent static and dynamic testing. Low cost telecommunications-grade optical fiber acts as the sensor using a high resolution commercial Optical Frequency Domain Reflectometer (OFDR) system providing distributed strain measurement at spatial resolutions as low as 2mm. Strain measurements using the optical fiber sensors are correlated to resistive strain gage measurements during static structural loading. Keywords: fiber optic, distributed strain sensing, Rayleigh scatter, optical frequency domain reflectometry

  17. Composite structures of steel and concrete beams, slabs, columns, and frames for buildings

    CERN Document Server

    Johnson, R P

    2008-01-01

    This book sets out the basic principles of composite construction with reference to beams, slabs, columns and frames, and their applications to building structures. It deals with the problems likely to arise in the design of composite members in buildings, and relates basic theory to the design approach of Eurocodes 2, 3 and 4.The new edition is based for the first time on the finalised Eurocode for steel/concrete composite structures.

  18. Discrete Material and Thickness Optimization of laminated composite structures including failure criteria

    DEFF Research Database (Denmark)

    Lund, Erik

    2017-01-01

    This work extends the Discrete Material and Thickness Optimization approach to structural optimization problems where strength considerations in the form of failure criteria are taken into account for laminated composite structures. It takes offset in the density approaches applied for stress...... constrained topology optimization of single-material problems and develops formulations for multi-material topology optimization problems applied for laminated composite structures. The method can be applied for both stress- and strain-based failure criteria. The large number of local constraints is reduced...

  19. Hybrid Composites for LH2 Fuel Tank Structure

    Science.gov (United States)

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

    2001-01-01

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

  20. Research Developments in Nondestructive Evaluation and Structural Health Monitoring for the Sustainment of Composite Aerospace Structures at NASA

    Science.gov (United States)

    Cramer, K. Elliott

    2016-01-01

    The use of composite materials continues to increase in the aerospace community due to the potential benefits of reduced weight, increased strength, and manufacturability. Ongoing work at NASA involves the use of the large-scale composite structures for spacecraft (payload shrouds, cryotanks, crew modules, etc). NASA is also working to enable both the use and sustainment of composites in commercial aircraft structures. One key to the sustainment of these large composite structures is the rapid, in-situ characterization of a wide range of potential defects that may occur during the vehicle's life. Additionally, in many applications it is necessary to monitor changes in these materials over their lifetime. Quantitative characterization through Nondestructive Evaluation (NDE) of defects such as reduced bond strength, microcracking, and delamination damage due to impact, are of particular interest. This paper will present an overview of NASA's applications of NDE technologies being developed for the characterization and sustainment of advanced aerospace composites. The approaches presented include investigation of conventional, guided wave, and phase sensitive ultrasonic methods and infrared thermography techniques for NDE. Finally, the use of simulation tools for optimizing and validating these techniques will also be discussed.

  1. Insensitive high-energy energetic structural material of tungsten-polytetrafluoroethylene-aluminum composites

    Directory of Open Access Journals (Sweden)

    Liu Wang

    2015-11-01

    Full Text Available Energetic structural material is a kind of materials that are inert under normal conditions but could produce exothermic chemical reaction when subjected to impact. This report shows a kind of energetic structural material of tungsten (W-polytetrafluoroethylene (PTFE-aluminum (Al with density of 4.12 g/cm3, excellent ductility and dynamic compressive strength of 96 MPa. Moreover, 50W-35PTFE-15Al (wt% can exhibit a high reaction energy value of more than 2 times of TNT per unit mass and 5 times of TNT per unit volume, respectively, but with excellent insensitivity compared with traditional explosives. Under thermal conditions, the W-PTFE-Al composite can keep stable at 773 K. Under impact loading, when the strain rate up to ∼4820 s−1 coupled with the absorbed energy per unit volume of 120 J/cm3, deflagration occurs and combustion lasts for 500 μs. During impact compressive deformation, the PTFE matrix is elongated into nano-fibers, thus significantly increases the reaction activity of W-PTFE-Al composites. The nano-fiber structure is necessary for the reaction of W-PTFE-Al composites. The formation of PTFE nano-fibers must undergo severe plastic deformation, and therefore the W-PTFE-Al composites exhibit excellent insensitivity and safety. Furthermore, the reaction mechanisms of W-PTFE-Al composites in argon and in air are revealed.

  2. Reconciling Basin-Scale Top-Down and Bottom-Up Methane Emission Measurements for Onshore Oil and Gas Development: Cooperative Research and Development Final Report, CRADA Number CRD-14-572

    Energy Technology Data Exchange (ETDEWEB)

    Heath, Garvin A. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-12-04

    The overall objective of the Research Partnership to Secure Energy for America (RPSEA)-funded research project is to develop independent estimates of methane emissions using top-down and bottom-up measurement approaches and then to compare the estimates, including consideration of uncertainty. Such approaches will be applied at two scales: basin and facility. At facility scale, multiple methods will be used to measure methane emissions of the whole facility (controlled dual tracer and single tracer releases, aircraft-based mass balance and Gaussian back-trajectory), which are considered top-down approaches. The bottom-up approach will sum emissions from identified point sources measured using appropriate source-level measurement techniques (e.g., high-flow meters). At basin scale, the top-down estimate will come from boundary layer airborne measurements upwind and downwind of the basin, using a regional mass balance model plus approaches to separate atmospheric methane emissions attributed to the oil and gas sector. The bottom-up estimate will result from statistical modeling (also known as scaling up) of measurements made at selected facilities, with gaps filled through measurements and other estimates based on other studies. The relative comparison of the bottom-up and top-down estimates made at both scales will help improve understanding of the accuracy of the tested measurement and modeling approaches. The subject of this CRADA is NREL's contribution to the overall project. This project resulted from winning a competitive solicitation no. RPSEA RFP2012UN001, proposal no. 12122-95, which is the basis for the overall project. This Joint Work Statement (JWS) details the contributions of NREL and Colorado School of Mines (CSM) in performance of the CRADA effort.

  3. Particulate Emissions Control using Advanced Filter Systems: Final Report for Argonne National Laboratory, Corning Inc. and Hyundai Motor Company CRADA Project

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Hee Je [Argonne National Lab. (ANL), Argonne, IL (United States); Choi, Seungmok [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-10-09

    This is a 3-way CRADA project working together with Corning, Inc. and Hyundai Motor Co. (HMC). The project is to understand particulate emissions from gasoline direct-injection engines (GDI) and their physico-chemical properties. In addition, this project focuses on providing fundamental information about filtration and regeneration mechanisms occurring in gasoline particulate filter (GPF) systems. For the work, Corning provides most advanced filter substrates for GPF applications and HMC provides three-way catalyst (TWC) coating services of these filter by way of a catalyst coating company. Then, Argonne National Laboratory characterizes fundamental behaviors of filtration and regeneration processes as well as evaluated TWC functionality for the coated filters. To examine aging impacts on TWC and GPF performance, the research team evaluates gaseous and particulate emissions as well as back-pressure increase with ash loading by using an engine-oil injection system to accelerate ash loading in TWC-coated GPFs.

  4. Laboratory Testing of the Boundary Layer Momentum Transfer Rotational Filter Systems, NETL-Innovatech, Inc., CRADA 98-F026, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    National Energy Technology Laboratory

    2000-08-22

    A patented dynamic mechanical filter developed by InnovaTech was previously shown to remove fine particulate matter from industrial process gas streams at ambient temperatures and pressures. An all-metal, high-temperature version of this novel media-less filter was fabricated under this Cooperative Research and Development Agreement (CRADA) with DOE/NETL-Morgantown for hot gas testing of the device. The technology is entirely different in both concept and design from conventional vortex separators, cyclones, or porous media filters. This new filtration concept is capable of separating heavy loading of fine particles without blinding, fouling or bridging, and would require minimal operational costs over its anticipated multi-year service life. The all-metal filter design eliminates thermal stress cracking and premature failure prevalent in conventional porous ceramic filters. In contrast, conventional porous media filters (i.e., ceramic cross-flow or candles) easily foul, require periodic cleaning (typically backpulsing), frequent replacement and subsequent disposal.

  5. Some Fundamental Aspects of Mechanics of Nano composite Materials and Structural Members

    International Nuclear Information System (INIS)

    Guz, A.N.; Rushchitsky, J.J.

    2013-01-01

    This paper is devoted to formulation and analysis of fundamental aspects of mechanics of nano composite materials and structural members. These aspects most likely do not exhaust all of the possible fundamental characteristics of mechanics of nano composite materials and structural members, but, nevertheless, they permit to form the skeleton of direction of mechanics in hand. The proposed nine aspects are described and commented briefly.

  6. CARBONIZED STARCH MICROCELLULAR FOAM-CELLULOSE FIBER COMPOSITE STRUCTURES

    Directory of Open Access Journals (Sweden)

    Andrew R. Rutledge

    2008-11-01

    Full Text Available The production of microporous carbon foams from renewable starch microcellular foam-fiber (SMCF-Fiber composites is described. Carbon foams are used in applications such as thermal insulation, battery electrodes, filters, fuel cells, and medical devices. SMCF-Fiber compos-ites were created from an aquagel. The water in the aquagel was exchanged with ethanol and then dried and carbonized. Higher amylose content starches and fiber contents of up to 4% improved the processability of the foam. The SMCF structure revealed agglomerates of swollen starch granules connected by a web of starch with pores in the 50-200 nanometer range. Heating the SMCF-fiber in a nitrogen atmosphere to temperatures between 350-700˚C produced carbon foams with a three-dimensional closed cell foam structure with cell diameters around 50 microns and pore walls around 1-3 microns. The stress versus strain compression data for carbonized samples displayed a linear elastic region and a plateau indicative of brittle crushing, typical of an elastic-brittle foam. The carbon foam products from these renew-able precursors are promising carbon structures with moderate strength and low density.

  7. Position and Orientation Tracking System graphical user interface. CRADA final report

    International Nuclear Information System (INIS)

    Barry, R.E.; Armstrong, G.A.; Burks, B.L.

    1997-01-01

    Under the Department of Energy's Robotics Technology Development Program (RTDP) Tank Waste Retrieval (TWR) program, a major effort is under way to develop technology for remediating the waste in underground storage tanks that contain radioactive and hazardous waste. A large part of the program's effort has gone towards development of remotely operable robotics equipment, including the Houdini Vehicle and the Position and Orientation Tracking System (POTS). Since planned operation of this equipment is to be completely remote, a significant effort is needed to ensure that operators have sufficient system information to operate the equipment efficiently and safely. ORNL developed POTS and RedZone Robotics, Inc. developed Houdini which can be operated together to provide both position and orientation descriptions of the Houdini vehicle, relative to a world reference frame, while operating inside an underground storage tank. The Houdini vehicle has been outfitted with an optical detection system that houses infrared detectors. The infrared detectors are part of the POTS tracking system. The sensors provide a set of timing pulses to the POTS control computer whenever a laser beam from one of the four POTS laser scanners strikes a detector. Using the pointing angle information from each POTS laser scanners, the POTS control computer is able to compute the pose of the Houdini vehicle at a rate of approximately 25 Hz. This information, along with the orientation of the Houdini's Schilling Titan II robot arm, is used to present the pose information to the operator in a 3-D graphical user interface using software that has been developed by this Cooperative Research and Development Agreement (CRADA). The graphical display presents the data to the operator in a format that is readily understood. The equipment operators are able to use the information in real-time to enhance the operator's ability to safely and efficiently control the remotely-operated vehicle

  8. Fibre-reinforced composite structures based on thermoplastic matrices with embedded piezoceramic modules

    International Nuclear Information System (INIS)

    Hufenbach, Werner A; Modler, Niels; Winkler, Anja; Ilg, Juergen; Rupitsch, Stefan J

    2014-01-01

    The paper presents recent developments for the integration of piezoceramic modules into fibre-reinforced composite structures based on thermoplastic matrices. An adapted hot pressing technology is conceptualized that allows for material homogeneous integration of the active modules. The main focus of this contribution is on the development of a robust and continuous manufacturing process of such novel active composites as well as on the operational testing of the produced samples. Therefore, selected specimens are manufactured as bending beams and investigated by means of electrical impedance measurements, modal analysis and structural excitation tests. In particular, the functionality of representative specimens is characterized based on frequency as well as spatially resolved deflection measurements. Moreover, the mentioned samples are compared to non-integrated piezoceramic modules and to equivalent passive reinforced composite structures. (paper)

  9. Ceramic matrix composites -- Advanced high-temperature structural materials

    International Nuclear Information System (INIS)

    Lowden, R.A.; Ferber, M.K.; DiPietro, S.G.

    1995-01-01

    This symposium on Ceramic Matrix Composites: Advanced High-Temperature Structural Materials was held at the 1994 MRS Fall Meeting in Boston, Massachusetts on November 28--December 2. The symposium was sponsored by the Department of Energy's Office of Industrial Technology's Continuous Fiber Ceramic Composites Program, the Air Force Office of Scientific Research, and NASA Lewis Research Center. Among the competing materials for advanced, high-temperature applications, ceramic matrix composites are leading candidates. The symposium was organized such that papers concerning constituents--fibers and matrices--were presented first, followed by composite processing, modeling of mechanical behavior, and thermomechanical testing. More stable reinforcements are necessary to enhance the performance and life of fiber-reinforced ceramic composites, and to ensure final acceptance of these materials for high-temperature applications. Encouraging results in the areas of polymer-derived SiC fibers and single crystal oxide filaments were given, suggesting composites with improved thermomechanical properties and stability will be realized in the near future. The significance of the fiber-matrix interface in the design and performance of these materials is evident. Numerous mechanical models to relate interface properties to composite behavior, and interpret test methods and data, were enthusiastically discussed. One issue of great concern for any advanced material for use in extreme environments is stability. This theme arose frequently throughout the symposium and was the topic of focus on the final day. Fifty nine papers have been processed separately for inclusion on the data base

  10. QuaBingo: A Prediction System for Protein Quaternary Structure Attributes Using Block Composition

    Directory of Open Access Journals (Sweden)

    Chi-Hua Tung

    2016-01-01

    Full Text Available Background. Quaternary structures of proteins are closely relevant to gene regulation, signal transduction, and many other biological functions of proteins. In the current study, a new method based on protein-conserved motif composition in block format for feature extraction is proposed, which is termed block composition. Results. The protein quaternary assembly states prediction system which combines blocks with functional domain composition, called QuaBingo, is constructed by three layers of classifiers that can categorize quaternary structural attributes of monomer, homooligomer, and heterooligomer. The building of the first layer classifier uses support vector machines (SVM based on blocks and functional domains of proteins, and the second layer SVM was utilized to process the outputs of the first layer. Finally, the result is determined by the Random Forest of the third layer. We compared the effectiveness of the combination of block composition, functional domain composition, and pseudoamino acid composition of the model. In the 11 kinds of functional protein families, QuaBingo is 23% of Matthews Correlation Coefficient (MCC higher than the existing prediction system. The results also revealed the biological characterization of the top five block compositions. Conclusions. QuaBingo provides better predictive ability for predicting the quaternary structural attributes of proteins.

  11. Rate Dependent Multicontinuum Progressive Failure Analysis of Woven Fabric Composite Structures under Dynamic Impact

    Directory of Open Access Journals (Sweden)

    James Lua

    2004-01-01

    Full Text Available Marine composite materials typically exhibit significant rate dependent response characteristics when subjected to extreme dynamic loading conditions. In this work, a strain-rate dependent continuum damage model is incorporated with multicontinuum technology (MCT to predict damage and failure progression for composite material structures. MCT treats the constituents of a woven fabric composite as separate but linked continua, thereby allowing a designer to extract constituent stress/strain information in a structural analysis. The MCT algorithm and material damage model are numerically implemented with the explicit finite element code LS-DYNA3D via a user-defined material model (umat. The effects of the strain-rate hardening model are demonstrated through both simple single element analyses for woven fabric composites and also structural level impact simulations of a composite panel subjected to various impact conditions. Progressive damage at the constituent level is monitored throughout the loading. The results qualitatively illustrate the value of rate dependent material models for marine composite materials under extreme dynamic loading conditions.

  12. SnO{sub 2}/ZnO composite structure for the lithium-ion battery electrode

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Mashkoor, E-mail: mashkoorahmad2003@yahoo.com [Beijing National Center for Electron Microscopy, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Material, China Iron and Steel Research Institute Group, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Nanomaterial Research Group, Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); Yingying, Shi [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Sun, Hongyu [Beijing National Center for Electron Microscopy, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Material, China Iron and Steel Research Institute Group, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Shen, Wanci [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Zhu, Jing, E-mail: jzhu@mail.tsinghua.edu.cn [Beijing National Center for Electron Microscopy, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Material, China Iron and Steel Research Institute Group, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2012-12-15

    In this article, SnO{sub 2}/ZnO composite structures have been synthesized by two steps hydrothermal method and investigated their lithium storage capacity as compared with pure ZnO. It has been found that these composite structures combining the large specific surface area, stability and catalytic activity of SnO{sub 2} micro-crystals, demonstrate the higher initial discharge capacity of 1540 mA h g{sup -1} with a Coulombic efficiency of 68% at a rate of 120 mA h g{sup -1} between 0.02 and 2 V and found much better than that of any previously reported ZnO based composite anodes. In addition, a significantly enhanced cycling performance, i.e., a reversible capacity of 497 mA h g{sup -1} is retained after 40 cycles. The improved lithium storage capacity and cycle life is attributed to the addition of SnO{sub 2} structure, which act as good electronic conductors and better accommodation of the large volume change during lithiation/delithiation process. - Graphical abstract: SnO{sub 2}/ZnO composite structures demonstrate the improved lithium storage capacity and cycle life as compared with pure ZnO nanostructure. Highlights: Black-Right-Pointing-Pointer Synthesis of SnO{sub 2}/ZnO composite structures by two steps hydrothermal approach. Black-Right-Pointing-Pointer Investigation of lithium storage capacity. Black-Right-Pointing-Pointer Excellent lithium storage capacity and cycle life of SnO{sub 2}/ZnO composite structures.

  13. 77 FR 50576 - Damage Tolerance and Fatigue Evaluation of Composite Rotorcraft Structures; OMB Approval of...

    Science.gov (United States)

    2012-08-22

    ... Composite Rotorcraft Structures; OMB Approval of Information Collection AGENCY: Federal Aviation... Rotorcraft Structures,'' which was published on December 1, 2011. DATES: The rule published on December 1... and Fatigue Evaluation of Composite Rotorcraft Structures,'' published in the Federal Register (76 FR...

  14. Preparation and wear behavior of polymer matrix composites with an interpenetrating network structure derived from natural sponge

    International Nuclear Information System (INIS)

    Wang Tianchi; Zhou Tianle; Xiong Dangsheng

    2010-01-01

    Natural sponge was used as a template to produce carbon/epoxy resin and (carbon+silicon carbide)/epoxy resin composites with interpenetrating network structures. Carbon with a network structure was first obtained by pyrolysis of the natural sponge. The composites were then obtained by injecting epoxy resin and silicone resin into the carbon. Their microstructures and wear properties were analyzed. The results show that the natural structure of sponge controlled the interpenetrating network structures of the composites. The netlike carbon in the composites reduced the wear rate of the epoxy resin. Compared with the carbon/epoxy resin composite, the (carbon+silicon carbide)/epoxy resin composite shows better wear resistance.

  15. Real-Time X-Ray Inspection of Composite Aircraft Structures

    National Research Council Canada - National Science Library

    Patricelli, F

    1978-01-01

    ...) for detection of defects, damage, and repair verification. The program included inspection of composite aircraft structural samples in the laboratory and an on site demonstration of RTR at the Naval Air Rework Facility (NARF...

  16. Composite Structure Monitoring using Direct Write Sensors, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This NASA SBIR Phase II project seeks to develop and demonstrate a suite of sensor products to monitor the health of composite structures. Sensors will be made using...

  17. Multifunctional Composites for Future Energy Storage in Aerospace Structures

    Directory of Open Access Journals (Sweden)

    Till Julian Adam

    2018-02-01

    Full Text Available Multifunctionalization of fiber-reinforced composites, especially by adding energy storage capabilities, is a promising approach to realize lightweight structural energy storages for future transport vehicles. Compared to conventional energy storage systems, energy density can be increased by reducing parasitic masses of non-energy-storing components and by benefitting from the composite meso- and microarchitectures. In this paper, the most relevant existing approaches towards multifunctional energy storages are reviewed and subdivided into five groups by distinguishing their degree of integration and their scale of multifunctionalization. By introducing a modified range equation for battery-powered electric aircrafts, possible range extensions enabled by multifunctionalization are estimated. Furthermore, general and aerospace specific potentials of multifunctional energy storages are discussed. Representing an intermediate degree of structural integration, experimental results for a multifunctional energy-storing glass fiber-reinforced composite based on the ceramic electrolyte Li1.4Al0.4Ti1.6(PO43 are presented. Cyclic voltammetry tests are used to characterize the double-layer behavior combined with galvanostatic charge–discharge measurements for capacitance calculation. The capacitance is observed to be unchanged after 1500 charge–discharge cycles revealing a promising potential for future applications. Furthermore, the mechanical properties are assessed by means of four-point bending and tensile tests. Additionally, the influence of mechanical loads on the electrical properties is also investigated, demonstrating the storage stability of the composites.

  18. 77 FR 4890 - Damage Tolerance and Fatigue Evaluation for Composite Rotorcraft Structures, and Damage Tolerance...

    Science.gov (United States)

    2012-02-01

    ...-AJ52, 2120-AJ51 Damage Tolerance and Fatigue Evaluation for Composite Rotorcraft Structures, and Damage Tolerance and Fatigue Evaluation for Metallic Structures; Correction AGENCY: Federal Aviation Administration... Tolerance and Fatigue Evaluation for Composite Rotorcraft Structures'' (76 FR 74655), published December 1...

  19. Neutron scattering analysis of rubber carbon black composite structure

    International Nuclear Information System (INIS)

    Hjelm, R.P. Jr.; Wampler, W.A.; Gerspacher, M.

    1994-01-01

    We explore the uses of small-angle neutron scattering to dissect component form, structure and distribution in carbon black-reinforced rubber by varying the contrast of the system relative to some fluid by changing the fluid scattering-length density. This is the method of contrast variation. Contrast variation allows us to separate scattering contributions from the different components. Here, we extend our studies on high surface area (HSA) carbon black suspended in cyclohexane/deuterocyclohexane to HSA mixed with polyisoprene as a gel of ''bound'' rubber swollen with the same solvent mixtures. Contrast variation of swollen composite gels shows that there are two length scales in the gel structure. Above 1 nm fluctuations in the carbon black predominate. Interactions with elastomer hold the HSA aggregates appart. Below 1 nm the scattering is largely from the elastomer. The smooth surface structure of the carbon black is unaltered by the interactions with elastomer and appears smooth over length scales above about 1 nm. These results show that contrast variation can provide information on composite structure that is not available by other means. This information relates to the reinforcement mechanism of elastomers by carbon blacks

  20. 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

  1. Structure-property correlations in nanocrystalline Al-Zr alloy composites

    International Nuclear Information System (INIS)

    Rittner, M.N.; Argonne National Lab., IL; Weertman, J.R.; Eastman, J.A.

    1996-01-01

    A study of the structure, grain size stability and Vickers microhardness of nanocrystalline aluminum-zirconium alloy composites was conducted. Samples were synthesized by the inert gas condensation process with electron beam evaporation. Transmission electron microscope examinations of the samples were performed at room and elevated temperatures. The behavior of the microstructures of the samples with time and temperature was investigated as a function of specimen composition. Vickers microhardness data were evaluated at room temperature in as-produced and polished compacted specimens. The local chemical composition of individual microhardness indents and average values of the grain size and porosity level were determined for a number of samples. Correlations among these microstructural variables and hardness were determined using multiple regression techniques

  2. Studies on structural properties of clay magnesium ferrite nano composite

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Manpreet, E-mail: manpreetchem@pau.edu; Singh, Mandeep [Department of Chemistry, Punjab Agricultural University, Ludhiana-141004 (India); Jeet, Kiran, E-mail: kiranjeet@pau.edu; Kaur, Rajdeep [Electron Microscopy and Nanoscience Laboratory, Punjab Agricultural University, Ludhiana-141004 (India)

    2015-08-28

    Magnesium ferrite-bentonite clay composite was prepared by sol-gel combustion method employing citric acid as complexing agent and fuel. The effect of clay on the structural properties was studied with X-ray diffraction (XRD), Fourier transform infrared (FT-IR) Spectroscopy, Scanning electron microscopy (SEM), SEM- Energy dispersive Spectroscope (EDS) and BET surface area analyzer. Decrease in particle size and density was observed on addition of bentonite clay. The BET surface area of nano composite containing just 5 percent clay was 74.86 m{sup 2}/g. Whereas porosity increased from 40.5 per cent for the pure magnesium ferrite to 81.0 percent in the composite showing that nano-composite has potential application as an adsorbent.

  3. A Study of the Utilization of Advanced Composites in Fuselage Structures of Commercial Aircraft

    Science.gov (United States)

    Watts, D. J.; Sumida, P. T.; Bunin, B. L.; Janicki, G. S.; Walker, J. V.; Fox, B. R.

    1985-01-01

    A study was conducted to define the technology and data needed to support the introduction of advanced composites in the future production of fuselage structure in large transport aircraft. Fuselage structures of six candidate airplanes were evaluated for the baseline component. The MD-100 was selected on the basis of its representation of 1990s fuselage structure, an available data base, its impact on the schedule and cost of the development program, and its availability and suitability for flight service evaluation. Acceptance criteria were defined, technology issues were identified, and a composite fuselage technology development plan, including full-scale tests, was identified. The plan was based on composite materials to be available in the mid to late 1980s. Program resources required to develop composite fuselage technology are estimated at a rough order of magnitude to be 877 man-years exclusive of the bird strike and impact dynamic test components. A conceptual composite fuselage was designed, retaining the basic MD-100 structural arrangement for doors, windows, wing, wheel wells, cockpit enclosure, major bulkheads, etc., resulting in a 32 percent weight savings.

  4. Thermally Conductive Structural 2D Composite Materials

    Science.gov (United States)

    2012-08-14

    Dimensional Pitch Polyimide Composite Micrographs ........ 27 Figure 23. 4-Ply Silver Polyimide Laminate ...through-thickness thermal conductivity of up to 20 W/m.K. This novel structural prepreg material will be developed through engineering of an optimal fiber...with an EPON 862/Epikure W epoxy resin system to form unidirectional prepreg tapes. Each prepreg was then cut to 6 inch by 6 inch plies and

  5. ECO-TECHNIQUE OF SEWER RENOVATION USING COMPOSITE SHELLS: STRUCTURAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    B. Attaf

    2015-07-01

    Full Text Available An eco-technical renovation of the sewage system is developed in this paper; this technique involves incorporating into the existing sewer a series of jointed prefabricated sandwich or composite shells. The purpose of his study is to determine the structural shell deflection, the high displacement areas and to validate the non-failure criterion for each ply constituting the inner and outer laminate facings. The numerical results were obtained at low cost by using the finite element method. Studies have focused on structural analysis of a typical shell unit with an ovoid form (egg-shaped section when it is subjected, during annular space filling operation, to pressure forces generated by wet concrete. To ensure the safety of the composite shell structure, Tsai-Hill criterion function is applied and results are presented for the most stressed plies

  6. Carbon composites in space vehicle structures

    Science.gov (United States)

    Mayer, N. J.

    1974-01-01

    Recent developments in the technology of carbon or graphite filaments now provide the designer with greatly improved materials offering high specific strength and modulus. Besides these advantages are properties which are distinctly useful for space applications and which provide feasibility for missions not obtainable by other means. Current applications include major and secondary structures of communications satellites. A number of R & D projects are exploring carbon-fiber application to rocket engine motor cases, advanced antenna systems, and space shuttle components. Future system studies are being made, based on the successful application of carbon fibers for orbiting space telescope assemblies, orbital transfer vehicles, and very large deployable energy generation systems. Continued technology development is needed in analysis, material standards, and advanced structural concepts to exploit the full potential of carbon filaments in composite materials.

  7. Mechanical properties of Composite Engineering Structures by Multivolume Micromechanical Modelling

    Directory of Open Access Journals (Sweden)

    B. Novotný

    2000-01-01

    Full Text Available Engineering structures often consist of elements having the character of a periodically repeated composite structure. A multivolume micromechanical model based on a representative cell division into r1 × r2 × r3 subcells with different elastic material properties has been used in this paper to derive macromechanical characteristics of the composite construction response to applied load and temperature changes. The multivolume method is based on ensuring the equilibrium of the considered volume on an average basis. In the same (average way, the continuity conditions of displacements and tractions at the interfaces between subcells and between neighboring representative elements are imposed, resulting in a homogenization procedure that eliminates the discrete nature of the composite model. The details of the method are shown for the case of a concrete block pavement. A parametric study is presented illustrating the influence of joint thickness, joint filling material properties and the quality of bonding between block and filler elements.

  8. Thermal properties of composite materials with a complex fractal structure

    International Nuclear Information System (INIS)

    Cervantes-Álvarez, F; Reyes-Salgado, J J; Dossetti, V; Carrillo, J L

    2014-01-01

    In this work, we report the thermal characterization of platelike composite samples made of polyester resin and magnetite inclusions. By means of photoacoustic spectroscopy and thermal relaxation, the thermal diffusivity, conductivity and volumetric heat capacity of the samples were experimentally measured. The volume fraction of the inclusions was systematically varied in order to study the changes in the effective thermal conductivity of the composites. For some samples, a static magnetic field was applied during the polymerization process, resulting in anisotropic inclusion distributions. Our results show a decrease in the thermal conductivity of some of the anisotropic samples, compared to the isotropic randomly distributed ones. Our analysis indicates that the development of elongated inclusion structures leads to the formation of magnetite and resin domains, causing this effect. We correlate the complexity of the inclusion structure with the observed thermal response through a multifractal and lacunarity analysis. All the experimental data are contrasted with the well known Maxwell–Garnett effective media approximation for composite materials. (paper)

  9. A Review of Structural Performance of Oil Palm Empty Fruit Bunch Fiber in Polymer Composites

    Directory of Open Access Journals (Sweden)

    Reza Mahjoub

    2013-01-01

    Full Text Available According to environmental concerns and financial problems, natural fibers have become interesting and fascinating nowadays to be used as an industrial material and structural material for rehabilitating of structures. Oil palm empty fruit bunch fiber (OPF is a natural fiber which is found a lot in tropical areas. Scientists have used OPF fiber with many types of resins such as epoxy, polypropylene, polyester, and phenol formaldehyde. Therefore, this paper focused on the properties of OPF fiber and gathered mechanical properties of OPF composites (OPF as reinforcement of polymer reported by other researchers in terms of tensile and flexural properties. Furthermore, the chemical surface modification methods to solve the interfacial bonding of fiber and polymer were mentioned. In addition, the results of hybrid composites of OPF were also discussed in this paper. Meanwhile, the results of composites were compared to pure resin properties and also the stress-strain diagram and internal strain energy of composites were considered. Besides, the effects of adding OPF to other composites to make a new hybrid composite were indicated. Finally, it is clear that the use of oil palm fiber composites for structural elements for bearing loads is not recommended but the usage of OPF composites for secondary structural elements may be recommended due to future researches.

  10. Eighth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, part 2

    Energy Technology Data Exchange (ETDEWEB)

    Starnes, J.H. Jr.; Bohon, H.L.; Garzon, S.B.

    1990-09-01

    Papers presented at the conference are compiled. The conference provided a forum for the scientific community to exchange composite structures design information and an opportunity to observe recent progress in composite structures design and technology. Part 2 contains papers related to the following subject areas: the application in design; methodology in design; and reliability in design.

  11. Eighth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, Part 2

    Science.gov (United States)

    Starnes, James H., Jr. (Compiler); Bohon, Herman L. (Compiler); Garzon, Sherry B. (Compiler)

    1990-01-01

    Papers presented at the conference are compiled. The conference provided a forum for the scientific community to exchange composite structures design information and an opportunity to observe recent progress in composite structures design and technology. Part 2 contains papers related to the following subject areas: the application in design; methodology in design; and reliability in design.

  12. Floristic Composition and Vegetation Structure of The KNUST ...

    African Journals Online (AJOL)

    The diversity, relative importance, canopy height and cover of plant species in the Kwame Nkrumah University of Science and Technology (KNUST) Botanic Garden were evaluated in five 1-ha plots using a stratified random sampling technique in order to build an understanding of its floristic composition and structure in two ...

  13. High Specific Stiffness Shafts and Advanced Bearing Coatings for Gas Turbine Engines Final Report CRADA No. TC-1089-95

    Energy Technology Data Exchange (ETDEWEB)

    Barbee, Troy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chin, Herbert [United Technologies Corporation, East Hartford, CT (United States)

    2017-11-09

    At the time of the CRADA, the largest in-service gas-turbine aircraft engines strove for increased thrust and power density to meet the requirements for take-off thrust, given the increase in take-off gross weight (TOGW) associated with longer range transport requirements. The trend in modem turbo shaft engines was toward turbine shafts with higher and higher length-to-diameter ratios, which reduced the shaft critical speed. Using co nventional shaft materials, this lead to shafts that needed to operate near or above sensitive shaft bending critical speeds, therefore requiring multiple bearings and/ or multiple squeeze-film dampers to control the dynamic response. Using new materials and d esign concepts this project demonstrated the use of new shaft materials which could provide increased shaft speed range above existing maximum engine speeds without encountering a critic al speed event and high vector deflections. This increased main shaft speed also resulted in decreased bearing life associated with lower heat dissipation and higher centrifugal forces. Thus, a limited effort was devoted to feasibility of higher performance bearing coatings to mitigate the speed effects.

  14. Active structural health monitoring of composite plates and sandwiches

    Directory of Open Access Journals (Sweden)

    Sadílek P.

    2013-12-01

    Full Text Available The aim of presented work is to design, assemble and test a functional system, that is able to reveal damage from impact loading. This is done by monitoring of change of spectral characteristics on a damaged structure that is caused by change of mechanical properties of material or by change of structure’s geometry. Excitation and monitoring of structures was done using piezoelectric patches. Unidirectional composite plate was tested for eigenfrequencies using chirp signal. The eigenfrequencies were compared to results from experiments with an impact hammer and consequently with results from finite element method. Same method of finding eigenfrequencies was used on a different unidirectional composite specimen. Series of impacts were performed. Spectrum of eigenfrequencies was measured on undamaged plate and then after each impact. Measurements of the plate with different level of damage were compared. Following experiments were performed on sandwich materials where more different failures may happen. Set of sandwich beams (cut out from one plate made of two outer composite layers and a foam core was investigated and subjected to several impacts. Several samples were impacted in the same manner to get comparable results. The impacts were performed with growing impact energy.

  15. Fabrication of a smart air intake structure using shape memory alloy wire embedded composite

    International Nuclear Information System (INIS)

    Jung, Beom-Seok; Kim, Min-Saeng; Kim, Ji-Soo; Kim, Yun-Mi; Lee, Woo-Yong; Ahn, Sung-Hoon

    2010-01-01

    Shape memory alloys (SMAs) have been actively studied in many fields utilizing their high energy density. Applying SMA wire-embedded composite to aerospace structures, such as air intake of jet engines and guided missiles, is attracting significant attention because it could generate a comparatively large actuating force. In this research, a scaled structure of SMA wire-embedded composite was fabricated for the air intake of aircraft. The structure was composed of several prestrained Nitinol (Ni-Ti) SMA wires embedded in intersection -shape glass fabric reinforced plastic (GFRP), and it was cured at room temperature for 72 h. The SMA wire-embedded GFRP could be actuated by applying electric current through the embedded SMA wires. The activation angle generated from the composite structure was large enough to make a smart air intake structure.

  16. Real-Time Impact Visualization Inspection of Aerospace Composite Structures with Distributed Sensors.

    Science.gov (United States)

    Si, Liang; Baier, Horst

    2015-07-08

    For the future design of smart aerospace structures, the development and application of a reliable, real-time and automatic monitoring and diagnostic technique is essential. Thus, with distributed sensor networks, a real-time automatic structural health monitoring (SHM) technique is designed and investigated to monitor and predict the locations and force magnitudes of unforeseen foreign impacts on composite structures and to estimate in real time mode the structural state when impacts occur. The proposed smart impact visualization inspection (IVI) technique mainly consists of five functional modules, which are the signal data preprocessing (SDP), the forward model generator (FMG), the impact positioning calculator (IPC), the inverse model operator (IMO) and structural state estimator (SSE). With regard to the verification of the practicality of the proposed IVI technique, various structure configurations are considered, which are a normal CFRP panel and another CFRP panel with "orange peel" surfaces and a cutout hole. Additionally, since robustness against several background disturbances is also an essential criterion for practical engineering demands, investigations and experimental tests are carried out under random vibration interfering noise (RVIN) conditions. The accuracy of the predictions for unknown impact events on composite structures using the IVI technique is validated under various structure configurations and under changing environmental conditions. The evaluated errors all fall well within a satisfactory limit range. Furthermore, it is concluded that the IVI technique is applicable for impact monitoring, diagnosis and assessment of aerospace composite structures in complex practical engineering environments.

  17. Laboratory Testing of the Boundary Layer Momentum Transfer Rotational Filter Systems, NETL-Innovatech, Inc., CRADA 98-F026, Final Report; FINAL

    International Nuclear Information System (INIS)

    National Energy Technology Laboratory

    2000-01-01

    A patented dynamic mechanical filter developed by InnovaTech was previously shown to remove fine particulate matter from industrial process gas streams at ambient temperatures and pressures. An all-metal, high-temperature version of this novel media-less filter was fabricated under this Cooperative Research and Development Agreement (CRADA) with DOE/NETL-Morgantown for hot gas testing of the device. The technology is entirely different in both concept and design from conventional vortex separators, cyclones, or porous media filters. This new filtration concept is capable of separating heavy loading of fine particles without blinding, fouling or bridging, and would require minimal operational costs over its anticipated multi-year service life. The all-metal filter design eliminates thermal stress cracking and premature failure prevalent in conventional porous ceramic filters. In contrast, conventional porous media filters (i.e., ceramic cross-flow or candles) easily foul, require periodic cleaning (typically backpulsing), frequent replacement and subsequent disposal

  18. Structure and composition of woody vegetation in two important bird areas in southern Zimbabwe

    NARCIS (Netherlands)

    Gandiwa, P.; Chinoitezvi, E.; Gandiwa, E.

    2013-01-01

    This study assessed the status of woody vegetation structure and composition in two Important Bird Areas (IBA) i.e. Manjinji Pan and Save-Runde Junction located in southeastern Zimbabwe. The objectives of this study were to: (i) determine the woody vegetation structure and composition of the study

  19. Full-Scale Structural and NDI Validation Tests of Bonded Composite Doublers for Commercial Aircraft Applications

    Energy Technology Data Exchange (ETDEWEB)

    Roach, D.; Walkington, P.

    1999-02-01

    Composite doublers, or repair patches, provide an innovative repair technique which can enhance the way aircraft are maintained. Instead of riveting multiple steel or aluminum plates to facilitate an aircraft repair, it is possible to bond a single Boron-Epoxy composite doubler to the damaged structure. Most of the concerns surrounding composite doubler technology pertain to long-term survivability, especially in the presence of non-optimum installations, and the validation of appropriate inspection procedures. This report focuses on a series of full-scale structural and nondestructive inspection (NDI) tests that were conducted to investigate the performance of Boron-Epoxy composite doublers. Full-scale tests were conducted on fuselage panels cut from retired aircraft. These full-scale tests studied stress reductions, crack mitigation, and load transfer capabilities of composite doublers using simulated flight conditions of cabin pressure and axial stress. Also, structures which modeled key aspects of aircraft structure repairs were subjected to extreme tension, shear and bending loads to examine the composite laminate's resistance to disbond and delamination flaws. Several of the structures were loaded to failure in order to determine doubler design margins. Nondestructive inspections were conducted throughout the test series in order to validate appropriate techniques on actual aircraft structure. The test results showed that a properly designed and installed composite doubler is able to enhance fatigue life, transfer load away from damaged structure, and avoid the introduction of new stress risers (i.e. eliminate global reduction in the fatigue life of the structure). Comparisons with test data obtained prior to the doubler installation revealed that stresses in the parent material can be reduced 30%--60% through the use of the composite doubler. Tests to failure demonstrated that the bondline is able to transfer plastic strains into the doubler and that

  20. Composition-Structure-Property Relations of Compressed Borosilicate Glasses

    Science.gov (United States)

    Svenson, Mouritz N.; Bechgaard, Tobias K.; Fuglsang, Søren D.; Pedersen, Rune H.; Tjell, Anders Ø.; Østergaard, Martin B.; Youngman, Randall E.; Mauro, John C.; Rzoska, Sylwester J.; Bockowski, Michal; Smedskjaer, Morten M.

    2014-08-01

    Hot isostatic compression is an interesting method for modifying the structure and properties of bulk inorganic glasses. However, the structural and topological origins of the pressure-induced changes in macroscopic properties are not yet well understood. In this study, we report on the pressure and composition dependences of density and micromechanical properties (hardness, crack resistance, and brittleness) of five soda-lime borosilicate glasses with constant modifier content, covering the extremes from Na-Ca borate to Na-Ca silicate end members. Compression experiments are performed at pressures ≤1.0 GPa at the glass transition temperature in order to allow processing of large samples with relevance for industrial applications. In line with previous reports, we find an increasing fraction of tetrahedral boron, density, and hardness but a decreasing crack resistance and brittleness upon isostatic compression. Interestingly, a strong linear correlation between plastic (irreversible) compressibility and initial trigonal boron content is demonstrated, as the trigonal boron units are the ones most disposed for structural and topological rearrangements upon network compaction. A linear correlation is also found between plastic compressibility and the relative change in hardness with pressure, which could indicate that the overall network densification is responsible for the increase in hardness. Finally, we find that the micromechanical properties exhibit significantly different composition dependences before and after pressurization. The findings have important implications for tailoring microscopic and macroscopic structures of glassy materials and thus their properties through the hot isostatic compression method.

  1. Structural Behaviour of Strengthened Composite Materials. Experimental Studies

    Directory of Open Access Journals (Sweden)

    Vlad Munteanu

    2007-01-01

    Full Text Available Masonry represents one of the earliest structural materials used by mankind. A lot of the ancient building structures were made using masonry. A large number of these buildings have been stated historical monuments. Most commonly masonry elements which are able to cover large spans was masonry arches. The paper makes a detailed presentation on structural behaviour and failure mechanisms of a horizontally loaded masonry arch. The arch model was built at a 1 : 1 scale using solid bricks and M10Z mortar. It was firstly loaded with vertically acting dead loads and with horizontal load acting in its plane. In this loading hypothesis, a plastic hinge occurred leading to the failure of the arch and loss of load bearing capacity. In the next stage of the experimental program, the arch was strengthened using a composite material membrane at the upper face. The membrane consisted in a continuous, glass-fiber fabric and epoxy resin. After proper curing, the same loading hypothesis was used. The failure mechanisms changed and a larger horizontal loading level was noticed. Further on, the arch was rehabilitated using a different composite material layout, the membrane was applied both on upper and bottom faces as well as partially on the lateral faces of the arch. This new rehabilitation layout leads to a significant increase in the load bearing capacity of the arch. The failure mechanisms were changed causing a significantly better overall structural behaviour of the arch.

  2. Strong composite films with layered structures prepared by casting silk fibroin-graphene oxide hydrogels

    Science.gov (United States)

    Huang, Liang; Li, Chun; Yuan, Wenjing; Shi, Gaoquan

    2013-04-01

    Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 +/- 16 MPa and a failure strain of 1.8 +/- 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 +/- 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets.Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 +/- 16 MPa and a failure strain of 1.8 +/- 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 +/- 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets. Electronic supplementary information (ESI) available: XPS spectrum of the SF-GO hybrid film, SEM images of lyophilized GO dispersion and the failure surface of GO film. See DOI: 10.1039/c3nr00196b

  3. Nonlinear damage detection in composite structures using bispectral analysis

    Science.gov (United States)

    Ciampa, Francesco; Pickering, Simon; Scarselli, Gennaro; Meo, Michele

    2014-03-01

    Literature offers a quantitative number of diagnostic methods that can continuously provide detailed information of the material defects and damages in aerospace and civil engineering applications. Indeed, low velocity impact damages can considerably degrade the integrity of structural components and, if not detected, they can result in catastrophic failure conditions. This paper presents a nonlinear Structural Health Monitoring (SHM) method, based on ultrasonic guided waves (GW), for the detection of the nonlinear signature in a damaged composite structure. The proposed technique, based on a bispectral analysis of ultrasonic input waveforms, allows for the evaluation of the nonlinear response due to the presence of cracks and delaminations. Indeed, such a methodology was used to characterize the nonlinear behaviour of the structure, by exploiting the frequency mixing of the original waveform acquired from a sparse array of sensors. The robustness of bispectral analysis was experimentally demonstrated on a damaged carbon fibre reinforce plastic (CFRP) composite panel, and the nonlinear source was retrieved with a high level of accuracy. Unlike other linear and nonlinear ultrasonic methods for damage detection, this methodology does not require any baseline with the undamaged structure for the evaluation of the nonlinear source, nor a priori knowledge of the mechanical properties of the specimen. Moreover, bispectral analysis can be considered as a nonlinear elastic wave spectroscopy (NEWS) technique for materials showing either classical or non-classical nonlinear behaviour.

  4. Methods of the Detection and Identification of Structural Defects in Saturated Metallic Composite Castings

    Directory of Open Access Journals (Sweden)

    Gawdzińska K.

    2017-09-01

    Full Text Available Diagnostics of composite castings, due to their complex structure, requires that their characteristics are tested by an appropriate description method. Any deviation from the specific characteristic will be regarded as a material defect. The detection of defects in composite castings sometimes is not sufficient and the defects have to be identified. This study classifies defects found in the structures of saturated metallic composite castings and indicates those stages of the process where such defects are likely to be formed. Not only does the author determine the causes of structural defects, describe methods of their detection and identification, but also proposes a schematic procedure to be followed during detection and identification of structural defects of castings made from saturated reinforcement metallic composites. Alloys examination was conducted after technological process, while using destructive (macroscopic tests, light and scanning electron microscopy and non-destructive (ultrasonic and X-ray defectoscopy, tomography, gravimetric method methods. Research presented in this article are part of author’s work on castings quality.

  5. PROGRESS ON DEVELOPING SONIC INFRARED IMAGING FOR DEFECT DETECTION IN COMPOSITE STRUCTURES

    International Nuclear Information System (INIS)

    Han Xiaoyan; He Qi; Li Wei; Newaz, Golam; Favro, Lawrence D.; Thomas, Robert L.

    2010-01-01

    At last year's QNDE conference, we presented our development of Sonic IR imaging technology in metal structures, with results from both experimental studies and theoretical computing. In the latest aircraft designs, such as the B787 from Boeing, composites have become the major materials in structures such as the fuselage and wings. This is in contrast to composites' use only in auxiliary components such as flaps and spoilers in the past. With today's advanced technology of fabrication, it is expected the new materials can be put in use in even more aircraft structures due to its light weight and high strength (high strength-to-weight ratio), high specific stiffness, tailorability of properties, design flexibility etc. Especially, with increases in fuel cost, reducing the aircraft's body weight becomes more and more appealing. In this presentation, we describe the progress on our development of Sonic IR imaging for aircraft composite structures. In particular, we describe the some unexpected results discovered while modeling delaminations. These results were later experimentally verified with an engineered delamination.

  6. The Evolution and Internal Structure of Jupiter and Saturn with Compositional Gradients

    NARCIS (Netherlands)

    Vazan, A.; Helled, R.; Podolak, M.; Kovetz, A.

    2016-01-01

    The internal structure of gas giant planets may be more complex than the commonly assumed core-envelope structure with an adiabatic temperature profile. Different primordial internal structures as well as various physical processes can lead to non-homogenous compositional distributions. A

  7. A review of optimization techniques used in the design of fibre composite structures for civil engineering applications

    International Nuclear Information System (INIS)

    Awad, Ziad K.; Aravinthan, Thiru; Zhuge, Yan; Gonzalez, Felipe

    2012-01-01

    Highlights: → We reviewed existing optimization techniques of fibre composite structures. → Proposed an improved methodology for design optimization. → Comparison showed the MRDO is most suitable. -- Abstract: Fibre composite structures have become the most attractive candidate for civil engineering applications. Fibre reinforced plastic polymer (FRP) composite materials have been used in the rehabilitation and replacement of the old degrading traditional structures or build new structures. However, the lack of design standards for civil infrastructure limits their structural applications. The majority of the existing applications have been designed based on the research and guidelines provided by the fibre composite manufacturers or based on the designer's experience. It has been a tendency that the final structure is generally over-designed. This paper provides a review on the available studies related to the design optimization of fibre composite structures used in civil engineering such as; plate, beam, box beam, sandwich panel, bridge girder, and bridge deck. Various optimization methods are presented and compared. In addition, the importance of using the appropriate optimization technique is discussed. An improved methodology, which considering experimental testing, numerical modelling, and design constrains, is proposed in the paper for design optimization of composite structures.

  8. Fabrication of Ni-Al/diamond composite based on layered and gradient structures of SHS system

    Directory of Open Access Journals (Sweden)

    Lu Jiafeng

    2017-01-01

    Full Text Available In this paper layered and gradient structures of Ni-Al SHS system were adopted to manufacture Ni-Al/diamond composites. The effect of the layered and the diamond mesh gradient structures of Ni-Al/diamond on the SHS process and the microstructure of the composites were investigated. It is found that with the increasing of the number of layers, the combustion wave velocity is decreased. The combustion wave velocity for diamond mesh size gradient structure of Ni-Al SHS is faster than that for the layered structure. A well bonding can be formed between diamond and the matrix in layered and gradient structure Ni-Al/diamond composites due to the melt of Ni-Cr brazing alloy.

  9. Airborne sound insulation of new composite wall structures

    Directory of Open Access Journals (Sweden)

    Ivanova Yonka

    2018-01-01

    Full Text Available Protection against noise is one of the essential requirements of the European Construction Product directive. In buildings, airborne sound insulation is used to define the acoustical quality between rooms. In order to develop wall structures with optimal sound insulation, an understanding of the physical origins of sound transmission is necessary. To develop a kind of knowledge that is applicable to the improvement of real walls and room barriers is the motive behind this study. The purpose of the work is to study the sound insulation of new composite wall structure.

  10. Polymer sol-gel composite inverse opal structures.

    Science.gov (United States)

    Zhang, Xiaoran; Blanchard, G J

    2015-03-25

    We report on the formation of composite inverse opal structures where the matrix used to form the inverse opal contains both silica, formed using sol-gel chemistry, and poly(ethylene glycol), PEG. We find that the morphology of the inverse opal structure depends on both the amount of PEG incorporated into the matrix and its molecular weight. The extent of organization in the inverse opal structure, which is characterized by scanning electron microscopy and optical reflectance data, is mediated by the chemical bonding interactions between the silica and PEG constituents in the hybrid matrix. Both polymer chain terminus Si-O-C bonding and hydrogen bonding between the polymer backbone oxygens and silanol functionalities can contribute, with the polymer mediating the extent to which Si-O-Si bonds can form within the silica regions of the matrix due to hydrogen-bonding interactions.

  11. Nonlinear Analysis and Scaling Laws for Noncircular Composite Structures Subjected to Combined Loads

    Science.gov (United States)

    Hilburger, Mark W.; Rose, Cheryl A.; Starnes, James H., Jr.

    2001-01-01

    Results from an analytical study of the response of a built-up, multi-cell noncircular composite structure subjected to combined internal pressure and mechanical loads are presented. Nondimensional parameters and scaling laws based on a first-order shear-deformation plate theory are derived for this noncircular composite structure. The scaling laws are used to design sub-scale structural models for predicting the structural response of a full-scale structure representative of a portion of a blended-wing-body transport aircraft. Because of the complexity of the full-scale structure, some of the similitude conditions are relaxed for the sub-scale structural models. Results from a systematic parametric study are used to determine the effects of relaxing selected similitude conditions on the sensitivity of the effectiveness of using the sub-scale structural model response characteristics for predicting the full-scale structure response characteristics.

  12. Structural characterization of degradation of ODS composite using SEM and XRM techniques

    Directory of Open Access Journals (Sweden)

    Oladayo OLANIRAN

    2017-07-01

    Full Text Available The structural characteristics and mechanisms of corrosion and wear of oxide dispersion strengthened stainless steel composite were investigated. Insitu synchrotron x-ray tomography was used as experimental technique for degradation analysis from the corrosion and tribology studies. Corrosion study was carried out using potential dynamic techniques while the tribology experiments were conducted using a tribometer with ball on disc method. The x-ray micro tomography data gave chronological description of crack initiation and propagation in 3D and revealed that pitting did not result from the oxide inclusion. The results also revealed the surface imaging capacity of SEM and XRM’s capability for imaging internal structures. Taber index measurement was used as a complimenting tool for tribology measurements. Tribological behaviour of the sinter Oxide Dispersion Strengthened (ODS steel composite depends on both the composition of the composite and the loading system.

  13. Structure, composition and mechanical properties of the silk fibres of ...

    Indian Academy of Sciences (India)

    The silk egg case and orb web of spiders are elaborate structures that are assembled from a number of components. We analysed the structure, the amino acid and fibre compositions, and the tensile properties of the silk fibres of the egg case of Nephila clavata. SEM shows that the outer and inner covers of the egg case ...

  14. Multiwavelength anomalous diffraction and diffraction anomalous fine structure to study composition and strain of semiconductor nano structures

    International Nuclear Information System (INIS)

    Favre-Nicolin, V.; Proietti, M.G.; Leclere, C.; Renevier, H.; Katcho, N.A.; Richard, M.I.

    2012-01-01

    The aim of this paper is to illustrate the use of Multi-Wavelength Anomalous Diffraction (MAD) and Diffraction Anomalous Fine Structure (DAFS) spectroscopy for the study of structural properties of semiconductor nano-structures. We give a brief introduction on the basic principles of these techniques providing a detailed bibliography. Then we focus on the data reduction and analysis and we give specific examples of their application on three different kinds of semiconductor nano-structures: Ge/Si nano-islands, AlN capped GaN/AlN Quantum Dots and AlGaN/AlN Nano-wires. We show that the combination of MAD and DAFS is a very powerful tool to solve the structural problem of these materials of high technological impact. In particular, the effects of composition and strain on diffraction are disentangled and composition can be determined in a reliable way, even at the interface between nano-structure and substrate. We show the great possibilities of this method and give the reader the basic tools to undertake its use. (authors)

  15. Electronic structure and physical properties of 13C carbon composite

    OpenAIRE

    Zhmurikov, Evgenij

    2015-01-01

    This review is devoted to the application of graphite and graphite composites in science and technology. Structure and electrical properties, as so technological aspects of producing of high-strength artificial graphite and dynamics of its destruction are considered. These type of graphite are traditionally used in the nuclear industry. Author was focused on the properties of graphite composites based on carbon isotope 13C. Generally, the review relies on the original results and concentrates...

  16. EDITORIAL Smart materials, multifunctional composites, and morphing structures: selected papers from the 20th International Conference on Adaptive Structures and Technologies (ICAST 2009) Smart materials, multifunctional composites, and morphing structures: selected papers from the 20th International Conference on Adaptive Structures and Technologies (ICAST 2009)

    Science.gov (United States)

    Liao, Wei-Hsin

    2010-12-01

    The 20th International Conference on Adaptive Structures and Technologies (ICAST) was held on 20-22 October 2009 in Hong Kong. This special section of Smart Materials and Structures is derived from the research papers presented at the conference. Of the 106 papers presented at the conference, 11 papers were reviewed and accepted for this special section, following the regular review procedures of the journal. This special section is focused on smart materials, multifunctional composites, and applications on morphing structures. Smart materials. Smart materials are the foundation of adaptive structures and intelligent systems. The development of new materials will lead to significant improvement in various applications. Three articles are focused on the fabrication of new materials and investigation of their behaviors: Barium strontium zirconate titanate ((Ba1-xSrx)(ZrxTi1-x)O3; BSZT, x = 0.25 and 0.75) ceramics with a highly crystalline structure were fabricated using the combustion technique. The microstructure of BSZT powders exhibited an almost-spherical morphology and had a porous agglomerated form. Polyaniline (PANI)/clay nanoparticles with unique core-shell structure were synthesized via Pickering emulsion polymerization. By dispersing PANI/clay nanoparticles in silicone oil, the ER fluid was made. Magnetic field effects were investigated on the deposition rate and surface morphology of chromium nitride coatings deposited by magnetron sputtering for superior hardness, excellent wear and oxidation resistance. The surface morphology of chromium nitride films was also examined by a scanning electron microscope (SEM). Multifunctional composites. Composites are made from two or more constituent materials so they can combine the best properties of different materials. Five papers deal with fabrication, testing, and modeling of various multifunctional composites: A new active structural fiber (ASF) was fabricated by coating a single carbon fiber with a concentric

  17. Structural Design of a Horizontal-Axis Tidal Current Turbine Composite Blade

    Energy Technology Data Exchange (ETDEWEB)

    Bir, G. S.; Lawson, M. J.; Li, Y.

    2011-10-01

    This paper describes the structural design of a tidal composite blade. The structural design is preceded by two steps: hydrodynamic design and determination of extreme loads. The hydrodynamic design provides the chord and twist distributions along the blade length that result in optimal performance of the tidal turbine over its lifetime. The extreme loads, i.e. the extreme flap and edgewise loads that the blade would likely encounter over its lifetime, are associated with extreme tidal flow conditions and are obtained using a computational fluid dynamics (CFD) software. Given the blade external shape and the extreme loads, we use a laminate-theory-based structural design to determine the optimal layout of composite laminas such that the ultimate-strength and buckling-resistance criteria are satisfied at all points in the blade. The structural design approach allows for arbitrary specification of the chord, twist, and airfoil geometry along the blade and an arbitrary number of shear webs. In addition, certain fabrication criteria are imposed, for example, each composite laminate must be an integral multiple of its constituent ply thickness. In the present effort, the structural design uses only static extreme loads; dynamic-loads-based fatigue design will be addressed in the future. Following the blade design, we compute the distributed structural properties, i.e. flap stiffness, edgewise stiffness, torsion stiffness, mass, moments of inertia, elastic-axis offset, and center-of-mass offset along the blade. Such properties are required by hydro-elastic codes to model the tidal current turbine and to perform modal, stability, loads, and response analyses.

  18. The fluid control mechanism of bionic structural heterogeneous composite materials and its potential application in enhancing pump efficiency

    Directory of Open Access Journals (Sweden)

    Limei Tian

    2015-11-01

    Full Text Available Studies have shown that the structure of dolphin skin controls fluid media dynamically. Gaining inspiration from this phenomenon, a kind of bionic structural heterogeneous composite material was designed. The bionic structural heterogeneous composite material is composed of two materials: a rigid metal base layer with bionic structures and an elastic polymer surface layer with the corresponding mirror structures. The fluid control mechanism of the bionic structural heterogeneous composite material was investigated using a fluid–solid interaction method in ANSYS Workbench. The results indicated that the bionic structural heterogeneous composite material’s fluid control mechanism is its elastic deformation, which is caused by the coupling action between the elastic surface material and the bionic structure. This deformation can decrease the velocity gradient of the fluid boundary layer through changing the fluid–solid actual contact surface and reduce the frictional force. The bionic structural heterogeneous composite material can also absorb some energy through elastic deformation and avoid energy loss. The bionic structural heterogeneous composite material was applied to the impeller of a centrifugal pump in a contrast experiment, increasing the pump efficiency by 5% without changing the hydraulic model of the impeller. The development of this bionic structural heterogeneous composite material will be straightforward from an engineering point of view, and it will have valuable practical applications.

  19. Mechanism Design and Testing of a Self-Deploying Structure Using Flexible Composite Tape Springs

    Science.gov (United States)

    Footdale, Joseph N.; Murphey, Thomas W.

    2014-01-01

    The detailed mechanical design of a novel deployable support structure that positions and tensions a membrane optic for space imagining applications is presented. This is a complex three-dimensional deployment using freely deploying rollable composite tape spring booms that become load bearing structural members at full deployment. The deployment tests successfully demonstrate a new architecture based on rolled and freely deployed composite tape spring members that achieve simultaneous deployment without mechanical synchronization. Proper design of the flexible component mounting interface and constraint systems, which were critical in achieving a functioning unit, are described. These flexible composite components have much potential for advancing the state of the art in deployable structures, but have yet to be widely adopted. This paper demonstrates the feasibility and advantages of implementing flexible composite components, including the design details on how to integrate with required traditional mechanisms.

  20. TiN/VN composites with core/shell structure for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Shanmu; Chen, Xiao [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101 (China); Gu, Lin [WPI Advanced Institute for Materials Research, Tohoku University, Sendai 9808577 (Japan); Zhou, Xinhong [Qingdao University of Science and Technology, Qingdao 266101 (China); Wang, Haibo; Liu, Zhihong; Han, Pengxian; Yao, Jianhua; Wang, Li [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101 (China); Cui, Guanglei, E-mail: cuigl@qibebt.ac.cn [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101 (China); Chen, Liquan [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101 (China); Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)

    2011-06-15

    Research highlights: {yields} Vanadium and titanium nitride nanocomposite with core-shell structure was prepared. {yields} TiN/VN composites with different V:Ti molar ratios were obtained. {yields} TiN/VN composites can provide promising electronic conductivity and favorable capacity storage. -- Abstract: TiN/VN core-shell composites are prepared by a two-step strategy involving coating of commercial TiN nanoparticles with V{sub 2}O{sub 5}.nH{sub 2}O sols followed by ammonia reduction. The highest specific capacitance of 170 F g{sup -1} is obtained when scanned at 2 mV s{sup -1} and a promising rate capacity performance is maintained at higher voltage sweep rates. These results indicate that these composites with good electronic conductivity can deliver a favorable capacity performance.

  1. Autonomous self-healing structural composites with bio-inspired design.

    Science.gov (United States)

    D'Elia, Eleonora; Eslava, Salvador; Miranda, Miriam; Georgiou, Theoni K; Saiz, Eduardo

    2016-05-05

    Strong and tough natural composites such as bone, silk or nacre are often built from stiff blocks bound together using thin interfacial soft layers that can also provide sacrificial bonds for self-repair. Here we show that it is possible exploit this design in order to create self-healing structural composites by using thin supramolecular polymer interfaces between ceramic blocks. We have built model brick-and-mortar structures with ceramic contents above 95 vol% that exhibit strengths of the order of MPa (three orders of magnitude higher than the interfacial polymer) and fracture energies that are two orders of magnitude higher than those of the glass bricks. More importantly, these properties can be fully recovered after fracture without using external stimuli or delivering healing agents. This approach demonstrates a very promising route towards the design of strong, ideal self-healing materials able to self-repair repeatedly without degradation or external stimuli.

  2. Ferrocement: A versatile composite structural material - A Review

    International Nuclear Information System (INIS)

    Memon, N. A.; Sumadi, S. R.

    2006-01-01

    The use of-based composites for structural application is becoming more popular with the introduction of new high performance materials. Ferrocement as a structural material has evolved from an appropriate technology applied for rural development to high performance and high durability construction material. The efficient use of ferrocement technology as per the requirements of the structures must be studied and developed in order to assist all the concerned parties concerned with structural activities. This paper is aimed to present the research made continuously to improve the ferrocement properties and performance and its uses in the different application and to encourage practical application of ferrocement especially in developing countries like Pakistan. This paper covers the theoretical, experimental and numerical studies conducted by several researchers to investigate the mechanical and structural properties of ferrocement. Also the efforts made to develop the design code offerrocement have been reviewed. (author)

  3. Development of Commercial Applications of a FAPY Alloy; TOPICAL

    International Nuclear Information System (INIS)

    Sikka, VK

    2001-01-01

    The Fe-16 at. (8.5 wt)% Al alloy, known as FAPY, has been identified as a superior material for heating element applications. However, while the 15-lb heats melted at the Oak Ridge National Laboratory (ORNL) could be processed into wire, the large heat melted at Hoskins Manufacturing Company (Hoskins) could not be processed under commercial processing conditions. The primary objective of the Cooperative Research and Development Agreement (CRADA) was to demonstrate that wire of the FAPY alloy could be produced under commercial conditions from air-induction-melted (AIM) heats. The specific aspects of this CRADA included: (1) Melting 15-lb heats by AIM or vacuum-induction melting (VIM) at ORNL. (2) Development of detailed processing steps including warm drawing and annealing temperature and time during cold-drawing steps. (3) Melting of 1400-lb heats at Hoskins by the Exo-Melt(trademark) process and their chemical analysis and microstructural characterization. (4) Development of tensile properties of sections of ingots from the large heats in the as-cast, hot-worked, and hot- and cold-worked conditions. (5) Microstructural characterization of cast and wrought structures and the fractured specimens. (6) Successful demonstration of processing of AIM heats at Hoskins to heating element wire. The aspects of this CRADA listed above have demonstrated that the FAPY alloy of the desired composition can be commercially produced by AIM by the use of the Exo-Melt(trademark) process. Furthermore, it also demonstrated that the wire processing steps developed for 15-lb heats at ORNL can be successfully applied to the production of wire from the large AIM heats

  4. Constitutive modeling and control of 1D smart composite structures

    Science.gov (United States)

    Briggs, Jonathan P.; Ostrowski, James P.; Ponte-Castaneda, Pedro

    1998-07-01

    Homogenization techniques for determining effective properties of composite materials may provide advantages for control of stiffness and strain in systems using hysteretic smart actuators embedded in a soft matrix. In this paper, a homogenized model of a 1D composite structure comprised of shape memory alloys and a rubber-like matrix is presented. With proportional and proportional/integral feedback, using current as the input state and global strain as an error state, implementation scenarios include the use of tractions on the boundaries and a nonlinear constitutive law for the matrix. The result is a simple model which captures the nonlinear behavior of the smart composite material system and is amenable to experiments with various control paradigms. The success of this approach in the context of the 1D model suggests that the homogenization method may prove useful in investigating control of more general smart structures. Applications of such materials could include active rehabilitation aids, e.g. wrist braces, as well as swimming/undulating robots, or adaptive molds for manufacturing processes.

  5. floristic composition and structure of the dry afromontane forest at ...

    African Journals Online (AJOL)

    ADMIN

    Key words/phrases: Bale Mountains, floristic composition, plant community, vegetation structure. INTRODUCTION .... from ground was estimated for each tree and shrub species by ...... and environmental factors characterizing coffee forests in ...

  6. Energy storage in structural composites by introducing CNT fiber/polymer electrolyte interleaves.

    Science.gov (United States)

    Senokos, Evgeny; Ou, Yunfu; Torres, Juan Jose; Sket, Federico; González, Carlos; Marcilla, Rebeca; Vilatela, Juan J

    2018-02-21

    This work presents a method to produce structural composites capable of energy storage. They are produced by integrating thin sandwich structures of CNT fiber veils and an ionic liquid-based polymer electrolyte between carbon fiber plies, followed by infusion and curing of an epoxy resin. The resulting structure behaves simultaneously as an electric double-layer capacitor and a structural composite, with flexural modulus of 60 GPa and flexural strength of 153 MPa, combined with 88 mF/g of specific capacitance and the highest power (30 W/kg) and energy (37.5 mWh/kg) densities reported so far for structural supercapacitors. In-situ electrochemical measurements during 4-point bending show that electrochemical performance is retained up to fracture, with minor changes in equivalent series resistance for interleaves under compressive stress. En route to improving interlaminar properties we produce grid-shaped interleaves that enable mechanical interconnection of plies by the stiff epoxy. Synchrotron 3D X-ray tomography analysis of the resulting hierarchical structure confirms the formation of interlaminar epoxy joints. The manuscript discusses encapsulation role of epoxy, demonstrated by charge-discharge measurements of composites immersed in water, a deleterious agent for ionic liquids. Finally, we show different architectures free of current collector and electrical insulators, in which both CNT fiber and CF act as active electrodes.

  7. Simulating Dynamic Vehicle Maneuvers Using Finite Elements For Use In Design Of Integrated Composite Structure

    OpenAIRE

    Angelini, Nicholas Alexander

    2014-01-01

    Formula SAE (FSAE) chassis systems are increasing being manufactured with integrated composite structures in an effort to increase the performance of the system while decreasing weight. The increased use of composite structures requires more details of the loading conditions and evaluation metrics than the mild steel structures they are replacing. The prototypical FSAE steel space frame chassis designs are heavily structured around the mandated safety rules that doubled as mostly satisfactory...

  8. Project on strengthening of structures using advanced composites

    Directory of Open Access Journals (Sweden)

    Recuero, A.

    1997-12-01

    Full Text Available Restoration, strengthening and rehabilitation of buildings becomes one of the more interesting aspects of the use of composites. Construction industry has not yet accepted the wide structural use of these new materials because it does not know the advantages of composites in comparison with traditional materials, such as concrete or steel. Engineers involved in design and construction are conservative and resist to changes. They require codes and specifications, what makes that an entity should lead the use of the new material or technology. At present, the experience needed to prepare those codes does not exist. Experimental tests and successful cases are necessary for the acceptance of these materials in construction. A project is presented, with the aim to provide the experimental basis, needed to update design codes and standards, and the technology for the use of these new composites in building and civil structures strengthening, taking actual pathology, quality and durability into account, as well as urban aesthetics. Research specialists in composites, structural analysis and testing, and in structural pathology, as well as composites and adhesives manufacturers and users, designers and final users will co-work in this project. This will allow that all relevant aspects of the problem be considered.

    La restauración, refuerzo o rehabilitación de estructuras resulta ser uno de los campos de aplicación de mayor interés y más directamente relacionado con los nuevos materiales compuestos. La Industria de la Construcción no ha aceptado aún el uso estructural extenso de los nuevos materiales compuestos porque todavía no conoce bien sus ventajas respecto a los materiales tradicionales, tales como el hormigón o el acero. Los profesionales implicados en el proyecto y en la ejecución de obras suelen ser conservadores y resistirse a los cambios. Para aceptar un nuevo material requieren disponer de normativa relativa a la nueva

  9. Size and composition dependence of the frozen structures in Co-based bimetallic clusters

    International Nuclear Information System (INIS)

    Li, Guojian; Wang, Qiang; Cao, Yongze; Du, Jiaojiao; He, Jicheng

    2012-01-01

    This Letter studies the size-dependent freezing of Co, Co–Ni, and Co–Cu clusters by using molecular dynamics with embedded atom method. Size effect occurs in these three types of clusters. The clusters with large sizes always freeze to form their bulk-like structures. However, the frozen structures for small sizes are generally related to their compositions. The icosahedral clusters are formed for Co clusters (for ⩽3.2 nm diameter) and also for Co–Ni clusters but at a larger size range (for ⩽4.08 nm). Upon the Co–Cu clusters, decahedral structure is obtained for small size (for 2.47 nm). The released energy induced the structural transformation plays a key role in the frozen structures. These results indicate that the preformed clusters with special structures can be tuned by controlling their compositions and sizes. -- Highlights: ► The size effect occurs in the Co, Co–Ni, and Co–Cu clusters. ► The clusters with large sizes always freeze to form their bulk-like structures. ► The frozen structures for small sizes are generally related to their compositions. ► Icosahedron is formed for Co and also for Co–Ni but at a larger size range. ► Upon the Co–Cu clusters, decahedral structure is obtained for small size.

  10. The Packaging Technology Study on Smart Composite Structure Based on The Embedded FBG Sensor

    Science.gov (United States)

    Zhang, Youhong; Chang, Xinlong; Zhang, Xiaojun; He, Xiangyong

    2018-03-01

    It is convenient to carry out the health monitoring of the solid rocket engine composite shell based on the embedded FBG sensor. In this paper, the packaging technology using one-way fiber layer of prepreg fiberglass/epoxy resin was proposed. The proposed packaging process is simple, and the packaged sensor structure size is flexible and convenient to use, at the mean time, the packaged structure has little effect on the pristine composite material structure.

  11. Structural and functional polymer-matrix composites for electromagnetic applications

    Science.gov (United States)

    Wu, Junhua

    This dissertation addresses the science and technology of functional and structural polymer-matrix composite materials for electromagnetic applications, which include electromagnetic interference (EMI) shielding and low observability (Stealth). The structural composites are continuous carbon fiber epoxy-matrix composites, which are widely used for airframes. The functional composites are composites with discontinuous fillers and in both bulk and coating forms. Through composite structure variation, attractive electromagnetic properties have been achieved. With no degradation of the tensile strength or modulus, the shielding effectiveness of the structural composites has been improved by enhancing multiple reflections through light activation of the carbon fiber. The multiple reflections loss of the electromagnetic wave increases from 1.1 to 10.2 dB at 1.0 GHz due to the activation. Such a large effect of multiple reflections has not been previously reported in any material. The observability of these composites has been lowered by decreasing the electrical conductivity (and hence decreasing the reflection loss) through carbon fiber coating. The incorporation of mumetal, a magnetic alloy particulate filler (28-40 mum size), in a latex paint has been found to be effective for enhancing the shielding only if the electrical resistivity of the resulting composite coating is below 10 O.cm, as rendered by a conductive particulate filler, such as nickel flake (14-20 mum size). This effectiveness (39 dB at 1.0 GHz) is attributed to the absorption of the electromagnetic wave by the mumetal and the nickel flake, with the high conductivity rendered by the presence of the nickel flake resulting in a relatively high reflection loss of 15.5 dB. Without the nickel flake, the mumetal gives only 3 dB of shielding and 1.5 dB of reflection loss at 1.0 GHz. Nickel powder (0.3-0.5 mum size) has been found to be an effective filler for improving the shielding of polyethersulfone (PES

  12. Photoluminescence and structural properties of CdSe quantum dot–gelatin composite films

    Energy Technology Data Exchange (ETDEWEB)

    Borkovska, L., E-mail: bork@isp.kiev.ua [V. Lashkaryov Institute of Semiconductor Physics of NAS of Ukraine, Pr. Nauky 41, 03028 Kyiv (Ukraine); Korsunska, N.; Stara, T.; Gudymenko, O.; Kladko, V. [V. Lashkaryov Institute of Semiconductor Physics of NAS of Ukraine, Pr. Nauky 41, 03028 Kyiv (Ukraine); Stroyuk, O.; Raevskaya, A. [L. Pysarzhevsky Institute of Physical Chemistry of NAS of Ukraine, Pr. Nauky 31, 03028 Kyiv (Ukraine); Kryshtab, T. [Instituto Politécnico Nacional – ESFM, Av. IPN, Ed.9 U.P.A.L.M., 07738 Mexico D.F. (Mexico)

    2014-11-15

    Optical and structural properties of composite films of CdSe quantum dots (QDs) embedded in gelatin matrix have been investigated by photoluminescence (PL), optical absorption and X-ray diffraction (XRD) methods. The optical absorption of the composite in the visible spectral range is found to be determined mainly by light absorption in the QDs. The decrease of the film transparency and the shift of the absorption edge to lower energies observed upon thermal annealing of the films at 140–160 °C are ascribed to the formation of chromophore groups in gelatin matrix. XRD patterns of the composite revealed helix to coil transition in gelatin matrix under thermal annealing of the composite at 100–160 °C. It is found that PL spectra of the composite are dominated by exciton and defect-related emission of the QDs and also contain weak emission of gelatin matrix. It is found that thermal annealing of the composite at 100–160 °C changes PL intensity and produces the shift of the PL bands to lower energies. As the annealed composite was kept in air for several months, the shift of exciton-related PL band position restored partially and the PL intensity increased. It is proposed that the increase of the PL intensity upon the thermal annealing of composite at 140 °C can be used for enhancement of the QD-related PL. Changes that occurred in the PL spectra of composite are ascribed to structural and chemical transformations in gelatin matrix and at the QD/gelatin interface.

  13. Structural, Magnetic, and Transport Properties of Polymer-Nano ferrite Composites

    International Nuclear Information System (INIS)

    Imam, N.G.G.

    2013-01-01

    In this work, a series of (x) BaTiO 3 / (1-x) Ni 0.5 Zn 0.5 Fe 2 O 4 nano composite samples were prepared using citrate auto combustion and the samples were classified into three groups.In first group: A series of (x) BaTiO 3 / (1-x) Ni 0.5 Zn 0.5 Fe 2 O 4 ; 0.0≤ x ≤ 1.0 were prepared by double sintering technique and citrate auto combustion method in comparison study due to different characterization analysis. The comparison reveals that from X-ray diffraction; all the samples from the two methods formed in single phase in both; cubic spinel structure NiZnFe 2 O 4 (NZF) ferrite and perovskite tetragonal structure BaTiO 3 (BTO).In group two, in another compassion, multiferroic hybrid nano composites based on different polymers as a matrix for the prepared magnetoelectric biferroic nano composite system 0.5 BaTiO 3 / 0.5Ni 0.5 Zn 0.5 Fe 2 O 4 that has been prepared by citrate auto combustion method. Four different polymers namely poly aniline (PANI), polyvinyl acetate (PVAc), Polyvinyl pyrrolidone (PVP), and polyethylene glycol (PEG), with fixed ration (1:1) with respect to the dispersed magnetoelectric nano composite.In group three, the nano composites materials with formula (1-y) [0.5 BaTiO 3 / 0.5 Ni 0.5 Zn 0.5 Fe 2 O 4 ] / (y) (PEG); 0.0 ≤y ≤+ 1.0, have been prepared at room temperature by weight mixing and cold pressing. Physical properties of nano composite materials consisting different ratios of polyethylene glycol were investigated. With the variation of y content, typical magnetic hysteresis loops of nano composites have been observed in the nano composites at room temperature. When PEG content increase, the saturation magnetization decrease. Meanwhile, the coercive force tends to stable. Additionally, the dielectric constant (ε ' ) and dielectric loss factor (ε '' ) of nano composites materials shift toward higher frequency. The value of (ε ' ) decreased with increasing frequency, which indicates that the major contribution

  14. Structure and chemical composition of layers adsorbed at interfaces with champagne.

    Science.gov (United States)

    Aguié-Béghin, V; Adriaensen, Y; Péron, N; Valade, M; Rouxhet, P; Douillard, R

    2009-11-11

    The structure and the chemical composition of the layer adsorbed at interfaces involving champagne have been investigated using native champagne, as well as ultrafiltrate (UFch) and ultraconcentrate (UCch) obtained by ultrafiltration with a 10(4) nominal molar mass cutoff. The layer adsorbed at the air/liquid interface was examined by surface tension and ellipsometry kinetic measurements. Brewster angle microscopy demonstrated that the layer formed on polystyrene by adsorption or drop evaporation was heterogeneous, with a domain structure presenting similarities with the layer adsorbed at the air/liquid interface. The surface chemical composition of polystyrene with the adlayer was determined by X-ray photoelectron spectroscopy (XPS). The contribution of champagne constituents varied according to the liquid (native, UFch, and UCch) and to the procedure of adlayer formation (evaporation, adsorption, and adsorption + rinsing). However, their chemical composition was not significantly influenced either by ultrafiltration or by the procedure of deposition on polystyrene. Modeling this composition in terms of classes of model compounds gave approximately 35% (w/w) of proteins and 65% (w/w) of polysaccharides. In the adlayer, the carboxyl groups or esters represent about 18% of carbon due to nonpolypeptidic compounds, indicating the presence of either uronic acids in the complex structure of pectic polysaccharides or of polyphenolic esters. This structural and chemical information and its relationship with the experimental procedures indicate that proteins alone cannot be used as a realistic model for the macromolecules forming the adsorption layer of champagne. Polysaccharides, the other major macromolecular components of champagne wine, are assembled with proteins at the interfaces, in agreement with the heterogeneous character of the adsorbed layer at interfaces.

  15. On a digital wireless impact-monitoring network for large-scale composite structures

    International Nuclear Information System (INIS)

    Yuan, Shenfang; Mei, Hanfei; Qiu, Lei; Ren, Yuanqiang

    2014-01-01

    Impact, which may occur during manufacture, service or maintenance, is one of the major concerns to be monitored throughout the lifetime of aircraft composite structures. Aiming at monitoring impacts online while minimizing the weight added to the aircraft to meet the strict limitations of aerospace engineering, this paper puts forward a new digital wireless network based on miniaturized wireless digital impact-monitoring nodes developed for large-scale composite structures. In addition to investigations on the design methods of the network architecture, time synchronization and implementation method, a conflict resolution method based on the feature parameters of digital sequences is first presented to address impact localization conflicts when several nodes are arranged close together. To verify the feasibility and stability of the wireless network, experiments are performed on a complex aircraft composite wing box and an unmanned aerial vehicle (UAV) composite wing. Experimental results show the successful design of the presented network. (paper)

  16. Structural health monitoring in composite materials using frequency response methods

    Science.gov (United States)

    Kessler, Seth S.; Spearing, S. Mark; Atalla, Mauro J.; Cesnik, Carlos E. S.; Soutis, Constantinos

    2001-08-01

    Cost effective and reliable damage detection is critical for the utilization of composite materials in structural applications. Non-destructive evaluation techniques (e.g. ultrasound, radiography, infra-red imaging) are available for use during standard repair and maintenance cycles, however by comparison to the techniques used for metals these are relatively expensive and time consuming. This paper presents part of an experimental and analytical survey of candidate methods for the detection of damage in composite materials. The experimental results are presented for the application of modal analysis techniques applied to rectangular laminated graphite/epoxy specimens containing representative damage modes, including delamination, transverse ply cracks and through-holes. Changes in natural frequencies and modes were then found using a scanning laser vibrometer, and 2-D finite element models were created for comparison with the experimental results. The models accurately predicted the response of the specimems at low frequencies, but the local excitation and coalescence of higher frequency modes make mode-dependent damage detection difficult and most likely impractical for structural applications. The frequency response method was found to be reliable for detecting even small amounts of damage in a simple composite structure, however the potentially important information about damage type, size, location and orientation were lost using this method since several combinations of these variables can yield identical response signatures.

  17. Application of Composite Structures in Bridge Engineering. Problems of Construction Process and Strength Analysis

    Science.gov (United States)

    Flaga, Kazimierz; Furtak, Kazimierz

    2015-03-01

    Steel-concrete composite structures have been used in bridge engineering from decades. This is due to rational utilisation of the strength properties of the two materials. At the same time, the reinforced concrete (or prestressed) deck slab is more favourable than the orthotropic steel plate used in steel bridges (higher mass, better vibration damping, longer life). The most commonly found in practice are composite girder bridges, particularly in highway bridges of small and medium spans, but the spans may reach over 200 m. In larger spans steel truss girders are applied. Bridge composite structures are also employed in cable-stayed bridge decks of the main girder spans of the order of 600, 800 m. The aim of the article is to present the cionstruction process and strength analysis problems concerning of this type of structures. Much attention is paid to the design and calculation of the shear connectors characteristic for the discussed objects. The authors focused mainly on the issues of single composite structures. The effect of assembly states on the stresses and strains in composite members are highlighted. A separate part of problems is devoted to the influence of rheological factors, i.e. concrete shrinkage and creep, as well as thermal factors on the stresses and strains and redistribution of internal forces.

  18. Design of Composite Structures Using Knowledge-Based and Case Based Reasoning

    Science.gov (United States)

    Lambright, Jonathan Paul

    1996-01-01

    A method of using knowledge based and case based reasoning to assist designers during conceptual design tasks of composite structures was proposed. The cooperative use of heuristics, procedural knowledge, and previous similar design cases suggests a potential reduction in design cycle time and ultimately product lead time. The hypothesis of this work is that the design process of composite structures can be improved by using Case-Based Reasoning (CBR) and Knowledge-Based (KB) reasoning in the early design stages. The technique of using knowledge-based and case-based reasoning facilitates the gathering of disparate information into one location that is easily and readily available. The method suggests that the inclusion of downstream life-cycle issues into the conceptual design phase reduces potential of defective, and sub-optimal composite structures. Three industry experts were interviewed extensively. The experts provided design rules, previous design cases, and test problems. A Knowledge Based Reasoning system was developed using the CLIPS (C Language Interpretive Procedural System) environment and a Case Based Reasoning System was developed using the Design Memory Utility For Sharing Experiences (MUSE) xviii environment. A Design Characteristic State (DCS) was used to document the design specifications, constraints, and problem areas using attribute-value pair relationships. The DCS provided consistent design information between the knowledge base and case base. Results indicated that the use of knowledge based and case based reasoning provided a robust design environment for composite structures. The knowledge base provided design guidance from well defined rules and procedural knowledge. The case base provided suggestions on design and manufacturing techniques based on previous similar designs and warnings of potential problems and pitfalls. The case base complemented the knowledge base and extended the problem solving capability beyond the existence of

  19. Composition, structure, and properties of iron-rich nontronites of different origins

    Energy Technology Data Exchange (ETDEWEB)

    Palchik, N. A., E-mail: nadezhda@igm.nsc.ru; Grigorieva, T. N.; Moroz, T. N. [Russian Academy of Sciences, Sobolev Institute of Geology and Mineralogy, Siberian Branch (Russian Federation)

    2013-03-15

    The composition, structure, and properties of smectites of different origins have been studied by X-ray diffraction, IR spectroscopy, scanning electron microscopy, and microprobe analysis. The results showed that nontronites of different origins differ in composition, properties, morphology, and IR spectroscopic characteristics. Depending on the degree of structural order and the negative charge of iron-silicate layers in nontronites, the shift of the 001 reflection to smaller angles as a result of impregnation with ethylene glycol (this shift is characteristic of the smectite group) occurs differently. The calculated values of the parameter b (from 9.11 to 9.14A) are valid for the extreme terms of dioctahedral smectite representatives: nontronites.

  20. Structural and electrical properties of functionalized multiwalled carbon nanotube/epoxy composite

    International Nuclear Information System (INIS)

    Gantayat, S.; Rout, D.; Swain, S. K.

    2016-01-01

    The effect of the functionalization of multiwalled carbon nanotube on the structure and electrical properties of composites was investigated. Samples based on epoxy resin with different weight percentage of MWCNTs were prepared and characterized. The interaction between MWCNT & epoxy resin was noticed by Fourier transform infrared spectroscopy (FTIR). The structure of functionalized multiwalled carbon nanotube (f-MWCNT) reinforced epoxy composite was studied by field emission scanning electron microscope (FESEM). The dispersion of f-MWCNT in epoxy resin was evidenced by high resolution transmission electron microscope (HRTEM). Electrical properties of epoxy/f-MWCNT nanocomposites were measured & the result indicated that the conductivity increased with increasing concentration of f-MWCNTs.

  1. Structural degradation of a large composite wind turbine blade in a full-scale fatigue test

    DEFF Research Database (Denmark)

    Chen, Xiao

    carried out at a coupon level to characterize fatigue degradation of composite materials, there is no much study focusing on fatigue degradation of rotor blades at a fullscale structural level. Do structural properties of composite blades degrade in a similar manner to what has been observed in material...... tests at a coupon level? What might be the concerns one should take into account when predicting residual structural properties of rotor blades? To answer, at least to a partial extent, these questions, this study conducts a full-scale fatigue test on a 47m composite rotor blade according to IEC 61400......Wind turbine blades are expected to sustain a high number of loading cycles typically up to a magnitude of 1,000 million during their targeted service lifetime of 20-25 years. Structural properties of composite blades degrade with the time. Although substantial studies, such as [1,2], have been...

  2. Effect of Discontinuities and Uncertainties on the Response and Failure of Composite Structures

    Science.gov (United States)

    Noor, Ahmed K.; Perry, Ferman W.; Poteat, Marcia M. (Technical Monitor)

    2000-01-01

    The overall goal of this research was to assess the effect of discontinuities and uncertainties on the nonlinear response and failure of composite structures subjected to combined mechanical and thermal loads. The four key elements of the study were: (1) development of simple and efficient procedures for the accurate determination of transverse shear and transverse normal stresses in structural sandwiches as well as in unstiffened and stiffened composite panels and shells; (2) study the effects of transverse stresses on the response, damage initiation and propagation in composite and sandwich structures; (3) use of hierarchical sensitivity coefficients to identify the major parameters that affect the response and damage in each of the different levels in the hierarchy (micro-mechanical, layer, panel, subcomponent and component levels); and (4) application of fuzzy set techniques to identify the range and variation of possible responses. The computational models developed were used in conjunction with experiments, to understand the physical phenomena associated with the nonlinear response and failure of composite and sandwich structures. A toolkit was developed for use in conjunction with deterministic analysis programs to help the designer in assessing the effect of uncertainties in the different computational model parameters on the variability of the response quantities.

  3. Elastic stability of biaxially loaded longitudinally stiffened composite structures.

    Science.gov (United States)

    Viswanathan, A. V.; Tamekuni, M.; Tripp, L. L.

    1973-01-01

    A linear analysis method is presented for the elastic stability of structures of uniform cross section, that may be idealized as an assemblage of laminated plate-strips, flat and curved, and beams. Each plate-strip and beam covers the entire length of the structure and is simply supported on the edges normal to the longitudinal axis. Arbitrary boundary conditions may be specified on any external longitudinal side of plate-strips. The structure or selected plate-strips may be loaded in any desired combination of inplane biaxial loads. The analysis simultaneously considers all modes of instability and is applicable for the buckling of laminated composite structures. Some numerical results are presented to indicate possible applications.

  4. Multi-level repair decision-making process for composite structures

    NARCIS (Netherlands)

    Dhanisetty, V.S.V.; Verhagen, W.J.C.; Curran, R.

    2016-01-01

    This paper details the development of a decision-making model that evaluates the multiple repair levels that a composite structure can undergo, each with its inherent achievable survivability and consequence to operations in terms of availability, costs, and scheduling. The goal of this model is to

  5. Structure and content of competitive group compositions in sports aerobics

    Directory of Open Access Journals (Sweden)

    Tetiana Moshenska

    2017-02-01

    Full Text Available Purpose: to make the analysis of modern competitive group compositions in sports aerobics. Material & Methods: pedagogical, sociological and methods of mathematical statistics were used. 10 coaches took part in the experimental part; analysis of protocols and video records of competitions of the aged category of children of 9–11 years old, who perform in the nomination of triplets and quintuples (group exercises, is carried out. Results: the content of competitive compositions and the allocated indicators are studied which defined it. Conclusions: the basic structural elements, which characterize competitive compositions, are allocated. Their components, quantity and time of performance are defined. It is established that variety of aerobic contents, spaces, and means of registration, musical compliance and logicality of creation of the whole competitive composition at high quality of performance characterizes teams – winners.

  6. Annealing Effect on Mechanical Properties of Ti-Al Alloy/Pure Ti Harmonic-Structured Composite by MM/SPS Process

    International Nuclear Information System (INIS)

    Yoshida, R; Tsuda, T; Fujiwara, H; Miyamoto, H; Ameyama, K

    2014-01-01

    The Ti-Al alloy/pure Ti harmonic-structured composite was produced by mechanical milling and spark plasma sintering process for improvement of low ductility at room temperature of Ti-Al alloy. The harmonic-structured composite with the dispersed area having coarse grained titanium and the network area having fine-grained Ti-48mol%Al alloy demonstrates high strength and high ductility at room temperature. The annealing effect of the microstructure on the mechanical properties in the Ti-Al alloy/pure Ti harmonic-structured composite are investigated. The microstructure of the Ti-Al alloy/pure Ti harmonic-structured composite annealed at 873 K, 973 K and 1073 K are maintained the Ti-Al network structure and pure Ti dispersed regions, the average grain size of pure Ti dispersed region is only coarsen by annealing. The harmonic-structured composite annealed at 873 K, 973 K and 1073 K are maintained the high hardness. The tensile results reveal that the Ti-Al alloy/pure Ti harmonic- structured composite annealed at 873 K exhibits high strength and especially high ductility

  7. A Spray-On Carbon Nanotube Artificial Neuron Strain Sensor for Composite Structural Health Monitoring

    Directory of Open Access Journals (Sweden)

    Gyeongrak Choi

    2016-07-01

    Full Text Available We present a nanocomposite strain sensor (NCSS to develop a novel structural health monitoring (SHM sensor that can be easily installed in a composite structure. An NCSS made of a multi-walled carbon nanotubes (MWCNT/epoxy composite was installed on a target structure with facile processing. We attempted to evaluate the NCSS sensing characteristics and benchmark compared to those of a conventional foil strain gauge. The response of the NCSS was fairly good and the result was nearly identical to the strain gauge. A neuron, which is a biomimetic long continuous NCSS, was also developed, and its vibration response was investigated for structural damage detection of a composite cantilever. The vibration response for damage detection was measured by tracking the first natural frequency, which demonstrated good result that matched the finite element (FE analysis.

  8. Fabrication of submicron structures in nanoparticle/polymer composite by holographic lithography and reactive ion etching

    Science.gov (United States)

    Zhang, A. Ping; He, Sailing; Kim, Kyoung Tae; Yoon, Yong-Kyu; Burzynski, Ryszard; Samoc, Marek; Prasad, Paras N.

    2008-11-01

    We report on the fabrication of nanoparticle/polymer submicron structures by combining holographic lithography and reactive ion etching. Silica nanoparticles are uniformly dispersed in a (SU8) polymer matrix at a high concentration, and in situ polymerization (cross-linking) is used to form a nanoparticle/polymer composite. Another photosensitive SU8 layer cast upon the nanoparticle/SU8 composite layer is structured through holographic lithography, whose pattern is finally transferred to the nanoparticle/SU8 layer by the reactive ion etching process. Honeycomb structures in a submicron scale are experimentally realized in the nanoparticle/SU8 composite.

  9. Structural design significance of tension-tension fatigue data on composites

    Science.gov (United States)

    Grimes, G. C.

    1977-01-01

    Constant cycle tension-tension fatigue and related static tension data have been generated on six single composite material/orientation combinations and twenty-one hybrid composite material/orientation combinations. Anomalies are related to the temperature rise and stopped interval creep, whereas endurance limit stresses (runouts) are associated with static proportional limit values, when they occur, and internal damage. The significance of these room temperature-dry data on the design allowables and weight of aerodynamic structueres is discussed. Such structures are helicopter rotor blades and wing and horizontal stabilizer lower surfaces. Typical criteria for turning these data into preliminary allowables are shown, as are examples of such allowables developed from the data. These values are then compared to those that might be used if the structures were made of metal.

  10. Damping analysis of cylindrical composite structures with enhanced viscoelastic properties

    DEFF Research Database (Denmark)

    Kliem, Mathias; Høgsberg, Jan Becker; Vanwalleghem, Joachim

    2018-01-01

    is forced to deform in shear mode. Thus, the vibration energy is dissipated as low grade frictional heat. This paper documents the efficiency of passive constrained layer damping treatments for low frequency vibrations of cylindrical composite specimens made of glass fibre-reinforced plastics. Different cross...... section geometries with shear webs have been investigated in order to study a beneficial effect on the damping characteristics of the cylinder. The viscoelastic damping layers are placed at different locations within the composite cylinder e.g. circumferential and along the neutral plane to evaluate...... in the neutral plane perpendicular to the bending load. The results are based on free decay tests of the composite structure....

  11. Active vibration control of smart hull structure using piezoelectric composite actuators

    International Nuclear Information System (INIS)

    Sohn, Jung Woo; Choi, Seung-Bok; Lee, Chul-Hee

    2009-01-01

    In this paper, active vibration control performance of the smart hull structure with macro-fiber composite (MFC) is evaluated. MFC is an advanced piezoelectric composite which has great flexibility and increased actuating performance compared to a monolithic piezoelectric ceramic patch. The governing equations of motion of the hull structure with MFC actuators are derived based on the classical Donnell–Mushtari shell theory. The actuating model for the interaction between hull structure and MFC is included in the governing equations. Subsequently, modal characteristics are investigated and compared with the results obtained from experiment. The governing equations of the vibration control system are then established and expressed in the state space form. A linear quadratic Gaussian (LQG) control algorithm is designed in order to effectively and actively control the imposed vibration. The controller is experimentally realized and vibration control performances are evaluated

  12. Validation of Material Models For Automotive Carbon Fiber Composite Structures Via Physical And Crash Testing (VMM Composites Project)

    Energy Technology Data Exchange (ETDEWEB)

    Coppola, Anthony [General Motors Company, Flint, MI (United States); Faruque, Omar [Ford Motor Company, Dearborn, MI (United States); Truskin, James F [FCA US LLC, Auburn Hills, MI (United States); Board, Derek [Ford Motor Company, Dearborn, MI (United States); Jones, Martin [Ford Motor Company, Dearborn, MI (United States); Tao, Jian [FCA US LLC, Auburn Hills, MI (United States); Chen, Yijung [Ford Motor Company, Dearborn, MI (United States); Mehta, Manish [M-Tech International LLC, Dubai (United Arab Emirates)

    2017-09-27

    As automotive fuel economy requirements increase, the push for reducing overall vehicle weight will likely include the consideration of materials that have not previously been part of mainstream vehicle design and manufacturing, including carbon fiber composites. Vehicle manufacturers currently rely on computer-aided engineering (CAE) methods as part of the design and development process, so going forward, the ability to accurately and predictably model carbon fiber composites will be necessary. If composites are to be used for structural components, this need applies to both, crash and quasi-static modeling. This final report covers the results of a five-year, $6.89M, 50% cost-shared research project between Department of Energy (DOE) and the US Advanced Materials Partnership (USAMP) under Cooperative Agreement DE-EE-0005661 known as “Validation of Material Models for Automotive Carbon Fiber Composite Structures Via Physical and Crash Testing (VMM).” The objective of the VMM Composites Project was to validate and assess the ability of physics-based material models to predict crash performance of automotive primary load-carrying carbon fiber composite structures. Simulation material models that were evaluated included micro-mechanics based meso-scale models developed by the University of Michigan (UM) and micro-plane models by Northwestern University (NWU) under previous collaborations with the DOE and Automotive Composites Consortium/USAMP, as well as five commercial crash codes: LS-DYNA, RADIOSS, VPS/PAM-CRASH, Abaqus, and GENOA-MCQ. CAE predictions obtained from seven organizations were compared with experimental results from quasi-static testing and dynamic crash testing of a thermoset carbon fiber composite front-bumper and crush-can (FBCC) system gathered under multiple loading conditions. This FBCC design was developed to demonstrate progressive crush, virtual simulation, tooling, fabrication, assembly, non-destructive evaluation and crash testing

  13. Recent NASA progress in composites. [application to spacecraft and aircraft structures

    Science.gov (United States)

    Heldenfels, R. R.

    1975-01-01

    The application of composites in aerospace vehicle structures is reviewed. Research and technology program results and specific applications to space vehicles, aircraft engines, and aircraft and helicopter structures are discussed in detail. Particular emphasis is given to flight service evaluation programs that are or will be accumulating substantial experience with secondary and primary structural components on military and commercial aircraft to increase confidence in their use.

  14. FORMATION REGULARITIES OF PHASE COMPOSITION, STRUCTURE AND PROPERTIES DURING MECHANICAL ALLOYING OF BINARY ALUMINUM COMPOSITES

    Directory of Open Access Journals (Sweden)

    F. G. Lovshenko

    2015-01-01

    Full Text Available The paper presents investigation results pertaining to  ascertainment of formation regularities of phase composition and structure during mechanical alloying of binary aluminium composites/substances. The invetigations have been executed while applying a wide range of methods, devices and equipment used in modern material science. The obtained data complement each other. It has been established that presence of oxide and hydro-oxide films on aluminium powder  and introduction of surface-active substance in the composite have significant effect on mechanically and thermally activated phase transformations and properties of semi-finished products.  Higher fatty acids have been used as a surface active substance.The mechanism of mechanically activated solid solution formation has been identified. Its essence is  a formation of  specific quasi-solutions at the initial stage of processing. Mechanical and chemical interaction between components during formation of other phases has taken place along with dissolution  in aluminium while processing powder composites. Granule basis is formed according to the dynamic recrystallization mechanism and possess submicrocrystal structural type with the granule dimension basis less than 100 nm and the grains are divided in block size of not more than 20 nm with oxide inclusions of 10–20 nm size.All the compounds  with the addition of  surface-active substances including aluminium powder without alloying elements obtained by processing in mechanic reactor are disperse hardened. In some cases disperse hardening is accompanied by dispersive and solid solution hardnening process. Complex hardening predetermines a high temperature of recrystallization in mechanically alloyed compounds,  its value exceeds 400 °C.

  15. Embedded Aligned Carbon Nanotube Sheets for Strain and Damage sensing in Composite Structures

    Science.gov (United States)

    Aly, Karim Aly Abdelomoaty Elsayed

    The world demand for fiber reinforced composite materials has been steadily increasing because of the widespread adoption of this class of material in many markets. The automotive, aerospace, marine and energy sectors account for a large percentage of this grow. Outstanding fatigue performance, high specific stiffness and strength, and low density are among the most important properties that fiber reinforced polymer composites offer. Furthermore, their properties can be tailored to meet the specific needs of the final applications. However, this class of material is composed of multiple layers of inhomogeneous and anisotropic constituents, i.e. fibers and matrix. Therefore, this laminated nature make the composite material prone to intrinsic damage including interfacial debonding and delamination and their strength and failure are dependent on the fiber architecture and direction of the applied stresses. Consequently, it is of prime importance to monitor the health of these structures. New and improved methods for early detection of damage and structural health monitoring of composite materials may allow for enhanced reliability, lifetime and performance while minimizing maintenance time during a composite part's service life. Over the last few decades different non-destructive methods and materials have been investigated for use as strain sensors. Since the discovery of carbon nanotubes (CNTs), they have attracted much research interest due to their superior electrical, thermal and mechanical properties as well as their high aspect ratio. In this context, CNTs have been used in the recent years to enable sensing capabilities. In this dissertation, the usage of CNTs for performing strain and damage sensing in composites is evaluated. This was enabled by embedding aligned sheets of two millimeters long, interconnected CNTs into laminated structures that were then subjected to different forms of mechanical loading. The localization of the CNT sheets inside the host

  16. Fabrication and characterization of aerosol-jet printed strain sensors for multifunctional composite structures

    Science.gov (United States)

    Zhao, Da; Liu, Tao; Zhang, Mei; Liang, Richard; Wang, Ben

    2012-11-01

    Traditional multifunctional composite structures are produced by embedding parasitic parts, such as foil sensors, optical fibers and bulky connectors. As a result, the mechanical properties of the composites, especially the interlaminar shear strength (ILSS), could be largely undermined. In the present study, we demonstrated an innovative aerosol-jet printing technology for printing electronics inside composite structures without degrading the mechanical properties. Using the maskless fine feature deposition (below 10 μm) characteristics of this printing technology and a pre-cure protocol, strain sensors were successfully printed onto carbon fiber prepregs to enable fabricating composites with intrinsic sensing capabilities. The degree of pre-cure of the carbon fiber prepreg on which strain sensors were printed was demonstrated to be critical. Without pre-curing, the printed strain sensors were unable to remain intact due to the resin flow during curing. The resin flow-induced sensor deformation can be overcome by introducing 10% degree of cure of the prepreg. In this condition, the fabricated composites with printed strain sensors showed almost no mechanical degradation (short beam shearing ILSS) as compared to the control samples. Also, the failure modes examined by optical microscopy showed no difference. The resistance change of the printed strain sensors in the composite structures were measured under a cyclic loading and proved to be a reliable mean strain gauge factor of 2.2 ± 0.06, which is comparable to commercial foil metal strain gauge.

  17. Critical joints in large composite primary aircraft structures. Volume 2: Technology demonstration test report

    Science.gov (United States)

    Bunin, Bruce L.

    1985-01-01

    A program was conducted to develop the technology for critical structural joints in composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. The results of four large composite multirow bolted joint tests are presented. The tests were conducted to demonstrate the technology for critical joints in highly loaded composite structure and to verify the analytical methods that were developed throughout the program. The test consisted of a wing skin-stringer transition specimen representing a stringer runout and skin splice on the wing lower surface at the side of the fuselage attachment. All tests were static tension tests. The composite material was Toray T-300 fiber with Ciba-Geigy 914 resin in 10 mil tape form. The splice members were metallic, using combinations of aluminum and titanium. Discussions are given of the test article, instrumentation, test setup, test procedures, and test results for each of the four specimens. Some of the analytical predictions are also included.

  18. Nanomembrane structures having mixed crystalline orientations and compositions

    Science.gov (United States)

    Lagally, Max G.; Scott, Shelley A.; Savage, Donald E.

    2014-08-12

    The present nanomembrane structures include a multilayer film comprising a single-crystalline layer of semiconductor material disposed between two other single-crystalline layers of semiconductor material. A plurality of holes extending through the nanomembrane are at least partially, and preferably entirely, filled with a filler material which is also a semiconductor, but which differs from the nanomembrane semiconductor materials in composition, crystal orientation, or both.

  19. Irradiation-induced structure and property changes in tokamak plasma-facing, carbon-carbon composites

    International Nuclear Information System (INIS)

    Burchell, T.D.

    1994-01-01

    Carbon-carbon composites are an attractive choice for fusion reactor plasma-facing components because of their low atomic number, superior thermal shock resistance, and low neutron activation. Next generation plasma fusion reactors, such as the International Thermonuclear Experimental Reactor (ITER), will require advanced carbon-carbon composite materials possessing high thermal conductivity to manage the anticipated severe heat loads. Moreover, ignition machines such as ITER will produce large neutron fluxes. Consequently, the influence of neutron damage on the structure and properties of carbon-carbon composite materials must be evaluated. Data from two irradiation experiments are reported and discussed here. Carbon-carbon composite materials were irradiated in target capsules in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). A peak damage dose of 4.7 displacements per atom (dpa) at 600 degree C was attained. The carbon materials irradiated included uni-directional, two-directional, and three-directional carbon-carbon composites. Dimensional changes are reported for the composite materials and are related to single crystal dimensional changes through fiber and composite structural models. Moreover, the irradiation-induced dimensional changes are reported and discussed in terms of their architecture, fiber type, and graphitization temperature. The effect of neutron irradiation on thermal conductivity of two three-directional, carbon-carbon composites is reported and the recovery of thermal conductivity due to thermal annealing is discussed

  20. Structure of Al-CF composites obtained by infiltration methods

    Directory of Open Access Journals (Sweden)

    A. Dolata-Grosz

    2011-04-01

    Full Text Available The structure of the composites obtained in infiltration processes 2D and 3D carbon preform by liquid Al alloy have been presented in thispaper. An aluminum alloy with silicon and manganese AlSi9Mn (trimal 37-TR37 was applied in the researches. As the reinforcementused carbon perform prepared with various protective barriers such as the nickel coating, the coating of silicon carbide and pyrolyticcarbon coating. Carbon preforms was prepared at the Institute for Lightweight Structures and Polymer Technology (ILK TU Dresden andat the Institute of Technology and Ceramic Systems (Fraunhofer-IKTS. The process of infiltration of carbon perform by liquid aluminiumalloy was carried out using a pressure-vacuum infiltration on the Degussa press and gas-pressure infiltration (GPI in an autoclavedesigned and built at the Department of Materials Technology at the Silesian University of Technology. The obtained composites werecharacterized by a regular shape, with no surface casting defects. The best connection of components was observed in AlSi9Mn/Cf(Nicomposite, obtained by gas-pressure infiltration method (GPI. On metallographic specimens, good interface between fibres and thealuminium matrix were observed. The obtained research results justify the application of nickel coatings on the fibres. During the failurecrack propagated across fiber. There was no presence of aluminum carbide on the fiber-matrix. It can be assumed that the composite willbe characterized by the good mechanical properties. However, this requires further experimental verification planned in the next stage of research, in the project realized within the DFG program: "3D textile reinforced aluminium matrix composites for complex loadingsituations in lightweight automobile and machine parts".

  1. Structural considerations in design of lightweight glass-fiber composite pressure vessels

    Science.gov (United States)

    Faddoul, J. R.

    1973-01-01

    The design concepts used for metal-lined glass-fiber composite pressure vessels are described, comparing the structural characteristics of the composite designs with each other and with homogeneous metal pressure vessels. Specific design techniques and available design data are identified. The discussion centers around two distinctly different design concepts, which provide the basis for defining metal lined composite vessels as either (1) thin-metal lined, or (2) glass fiber reinforced (GFR). Both concepts are described and associated development problems are identified and discussed. Relevant fabrication and testing experience from a series of NASA-Lewis Research Center development efforts is presented.

  2. Harnessing the bistable composite shells to design a tunable phononic band gap structure

    Science.gov (United States)

    Li, Yi; Xu, Yanlong

    2018-02-01

    By proposing a system composed of an array of bistable composite shells immersed in air, we develop a new class of periodic structure to control the propagation of sound. Through numerical investigation, we find that the acoustic band gap of this system can be switched on and off by triggering the snap through deformation of the bistable composite shells. The shape of cross section and filling fraction of unit cell can be altered by different number of bistable composite shells, and they have strong impact on the position and width of the band gap. The proposed concept paves the way of using the bistable structures to design a new class of metamaterials that can be enable to manipulate sound.

  3. Simulation of the structure and calculation of the thermal conductivity of napped composites

    International Nuclear Information System (INIS)

    Berezko, S.N.; Zarichnyak, Yu.P.; Korenev, P.A.

    1995-01-01

    We propose a model of the structure of a napped composite. Characteristic trends in the structure of the material are delineated, and the effective thermal conductivity of the model structure is calculated for these trends with allowance for conduction and radiation

  4. Thermally Stable and Electrically Conductive, Vertically Aligned Carbon Nanotube/Silicon Infiltrated Composite Structures for High-Temperature Electrodes.

    Science.gov (United States)

    Zou, Qi Ming; Deng, Lei Min; Li, Da Wei; Zhou, Yun Shen; Golgir, Hossein Rabiee; Keramatnejad, Kamran; Fan, Li Sha; Jiang, Lan; Silvain, Jean-Francois; Lu, Yong Feng

    2017-10-25

    Traditional ceramic-based, high-temperature electrode materials (e.g., lanthanum chromate) are severely limited due to their conditional electrical conductivity and poor stability under harsh circumstances. Advanced composite structures based on vertically aligned carbon nanotubes (VACNTs) and high-temperature ceramics are expected to address this grand challenge, in which ceramic serves as a shielding layer protecting the VACNTs from the oxidation and erosive environment, while the VACNTs work as a conductor. However, it is still a great challenge to fabricate VACNT/ceramic composite structures due to the limited diffusion of ceramics inside the VACNT arrays. In this work, we report on the controllable fabrication of infiltrated (and noninfiltrated) VACNT/silicon composite structures via thermal chemical vapor deposition (CVD) [and laser-assisted CVD]. In laser-assisted CVD, low-crystalline silicon (Si) was quickly deposited at the VACNT subsurfaces/surfaces followed by the formation of high-crystalline Si layers, thus resulting in noninfiltrated composite structures. Unlike laser-assisted CVD, thermal CVD activated the precursors inside and outside the VACNTs simultaneously, which realized uniform infiltrated VACNT/Si composite structures. The growth mechanisms for infiltrated and noninfiltrated VACNT/ceramic composites, which we attributed to the different temperature distributions and gas diffusion mechanism in VACNTs, were investigated. More importantly, the as-farbicated composite structures exhibited excellent multifunctional properties, such as excellent antioxidative ability (up to 1100 °C), high thermal stability (up to 1400 °C), good high velocity hot gas erosion resistance, and good electrical conductivity (∼8.95 Sm -1 at 823 K). The work presented here brings a simple, new approach to the fabrication of advanced composite structures for hot electrode applications.

  5. Structural evolution of ZTA composites during synthesis and processing

    Czech Academy of Sciences Publication Activity Database

    Exare, C.; Kiat, J. M.; Guiblin, N.; Porcher, F.; Petříček, Václav

    2015-01-01

    Roč. 35, č. 4 (2015), s. 1273-1283 ISSN 0955-2219 R&D Projects: GA ČR(CZ) GA14-03276S Institutional support: RVO:68378271 Keywords : ceramic s * alumina–zirconia composites * structural properties * strain effect * size effect Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.933, year: 2015

  6. Advanced Ceramic Matrix Composites with Multifunctional and Hybrid Structures

    Science.gov (United States)

    Singh, Mrityunjay; Morscher, Gregory N.

    2004-01-01

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

  7. Design and Optimization of Composite Automotive Hatchback Using Integrated Material-Structure-Process-Performance Method

    Science.gov (United States)

    Yang, Xudong; Sun, Lingyu; Zhang, Cheng; Li, Lijun; Dai, Zongmiao; Xiong, Zhenkai

    2018-03-01

    The application of polymer composites as a substitution of metal is an effective approach to reduce vehicle weight. However, the final performance of composite structures is determined not only by the material types, structural designs and manufacturing process, but also by their mutual restrict. Hence, an integrated "material-structure-process-performance" method is proposed for the conceptual and detail design of composite components. The material selection is based on the principle of composite mechanics such as rule of mixture for laminate. The design of component geometry, dimension and stacking sequence is determined by parametric modeling and size optimization. The selection of process parameters are based on multi-physical field simulation. The stiffness and modal constraint conditions were obtained from the numerical analysis of metal benchmark under typical load conditions. The optimal design was found by multi-discipline optimization. Finally, the proposed method was validated by an application case of automotive hatchback using carbon fiber reinforced polymer. Compared with the metal benchmark, the weight of composite one reduces 38.8%, simultaneously, its torsion and bending stiffness increases 3.75% and 33.23%, respectively, and the first frequency also increases 44.78%.

  8. Physical disturbance to ecological niches created by soil structure alters community composition of methanotrophs.

    Science.gov (United States)

    Kumaresan, Deepak; Stralis-Pavese, Nancy; Abell, Guy C J; Bodrossy, Levente; Murrell, J Colin

    2011-10-01

    Aggregates of different sizes and stability in soil create a composite of ecological niches differing in terms of physico-chemical and structural characteristics. The aim of this study was to identify, using DNA-SIP and mRNA-based microarray analysis, whether shifts in activity and community composition of methanotrophs occur when ecological niches created by soil structure are physically perturbed. Landfill cover soil was subject to three treatments termed: 'control' (minimal structural disruption), 'sieved' (sieved soil using 2 mm mesh) and 'ground' (grinding using mortar and pestle). 'Sieved' and 'ground' soil treatments exhibited higher methane oxidation potentials compared with the 'control' soil treatment. Analysis of the active community composition revealed an effect of physical disruption on active methanotrophs. Type I methanotrophs were the most active methanotrophs in 'sieved' and 'ground' soil treatments, whereas both Type I and Type II methanotrophs were active in the 'control' soil treatment. The result emphasize that changes to a particular ecological niche may not result in an immediate change to the active bacterial composition and change in composition will depend on the ability of the bacterial communities to respond to the perturbation. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  9. A Multiscale, Nonlinear, Modeling Framework Enabling the Design and Analysis of Composite Materials and Structures

    Science.gov (United States)

    Bednarcyk, Brett A.; Arnold, Steven M.

    2012-01-01

    A framework for the multiscale design and analysis of composite materials and structures is presented. The ImMAC software suite, developed at NASA Glenn Research Center, embeds efficient, nonlinear micromechanics capabilities within higher scale structural analysis methods such as finite element analysis. The result is an integrated, multiscale tool that relates global loading to the constituent scale, captures nonlinearities at this scale, and homogenizes local nonlinearities to predict their effects at the structural scale. Example applications of the multiscale framework are presented for the stochastic progressive failure of a SiC/Ti composite tensile specimen and the effects of microstructural variations on the nonlinear response of woven polymer matrix composites.

  10. K-shuff: A Novel Algorithm for Characterizing Structural and Compositional Diversity in Gene Libraries.

    Science.gov (United States)

    Jangid, Kamlesh; Kao, Ming-Hung; Lahamge, Aishwarya; Williams, Mark A; Rathbun, Stephen L; Whitman, William B

    2016-01-01

    K-shuff is a new algorithm for comparing the similarity of gene sequence libraries, providing measures of the structural and compositional diversity as well as the significance of the differences between these measures. Inspired by Ripley's K-function for spatial point pattern analysis, the Intra K-function or IKF measures the structural diversity, including both the richness and overall similarity of the sequences, within a library. The Cross K-function or CKF measures the compositional diversity between gene libraries, reflecting both the number of OTUs shared as well as the overall similarity in OTUs. A Monte Carlo testing procedure then enables statistical evaluation of both the structural and compositional diversity between gene libraries. For 16S rRNA gene libraries from complex bacterial communities such as those found in seawater, salt marsh sediments, and soils, K-shuff yields reproducible estimates of structural and compositional diversity with libraries greater than 50 sequences. Similarly, for pyrosequencing libraries generated from a glacial retreat chronosequence and Illumina® libraries generated from US homes, K-shuff required >300 and 100 sequences per sample, respectively. Power analyses demonstrated that K-shuff is sensitive to small differences in Sanger or Illumina® libraries. This extra sensitivity of K-shuff enabled examination of compositional differences at much deeper taxonomic levels, such as within abundant OTUs. This is especially useful when comparing communities that are compositionally very similar but functionally different. K-shuff will therefore prove beneficial for conventional microbiome analysis as well as specific hypothesis testing.

  11. Analysis and modelling composite timber-concrete systems: Design of bridge structure according to EN

    Directory of Open Access Journals (Sweden)

    Manojlović Dragan

    2016-01-01

    Full Text Available Timber-concrete composite structures are already applied more than 80 years in engineering practice, went trought the intuitive problem solution to the fully prefabricated hybride assemblies for dry building. The development path of timber-concrete composites was always followed by extensive theoretical and experimental research, whose results were successfully implemented in practice, i.e. on the market, but till presence didn't result in modern designer's code. In expectation of new European codes for timber-concrete composites, the objective of the paper is to provide a comprehensive review of available standards provisions and recent conclusions from literature. The key issues for practical design are highlighted and ilustrated on the example of glulam composite arch bridge structure with concrete deck, according the Eurocodes.

  12. Analysis of the connection of the timber-fiber concrete composite structure

    Science.gov (United States)

    Holý, Milan; Vráblík, Lukáš; Petřík, Vojtěch

    2017-09-01

    This paper deals with an implementation of the material parameters of the connection to complex models for analysis of the timber-fiber concrete composite structures. The aim of this article is to present a possible way of idealization of the continuous contact model that approximates the actual behavior of timber-fiber reinforced concrete structures. The presented model of the connection was derived from push-out shear tests. It was approved by use of the nonlinear numerical analysis, that it can be achieved a very good compliance between results of numerical simulations and results of the experiments by a suitable choice of the material parameters of the continuous contact. Finally, an application for an analytical calculation of timber-fiber concrete composite structures is developed for the practical use in engineering praxis. The input material parameters for the analytical model was received using data from experiments.

  13. Energy density and rate limitations in structural composite supercapacitors

    Science.gov (United States)

    Snyder, J. F.; Gienger, E.; Wetzel, E. D.; Xu, K.

    2012-06-01

    The weight and volume of conventional energy storage technologies greatly limits their performance in mobile platforms. Traditional research efforts target improvements in energy density to reduce device size and mass. Enabling a device to perform additional functions, such as bearing mechanical load, is an alternative approach as long as the total mass efficiency exceeds that of the individual materials it replaces. Our research focuses on structural composites that function as batteries and supercapacitors. These multifunctional devices could be used to replace conventional structural components, such as vehicle frame elements, to provide significant system-level weight reductions and extend mission times. Our approach is to design structural properties directly into the electrolyte and electrode materials. Solid polymer electrolyte materials bind the system and transfer load to the fibers while conducting ions between the electrodes. Carbon fiber electrodes provide a route towards optimizing both energy storage and load-bearing capabilities, and may also obviate the need for a separate current collector. The components are being integrated using scalable, cost-effective composite processing techniques that are amenable to complex part shapes. Practical considerations of energy density and rate behavior are described here as they relate to materials used. Our results highlight the viability as well as the challenges of this multifunctional approach towards energy storage.

  14. An Improved Design Methodology for Modeling Thick-Section Composite Structures Using a Multiscale Approach

    Science.gov (United States)

    2012-09-01

    case study no. 2. The multiaxial loading combined with XZ and YZ Poisson ratio effects contributes to strains in the Z-direction of the sample. The...E. A Continuum Damage Model for Fiber Reinforced Laminates Based on Ply Failure Mechanisms, Composite Structures. Fifteenth International...output parameters, stiffness ratios , to analyze the nonlinear response and progressive failure of the composite structure is developed. These new

  15. ALL NATURAL COMPOSITE SANDWICH BEAMS FOR STRUCTURAL APPLICATIONS. (R829576)

    Science.gov (United States)

    As part of developing an all natural composite roof for housing application,structural panels and unit beams were manufactured out of soybean oil based resinand natural fibers (flax, cellulose, pulp, recycled paper, chicken feathers)using vacuum assisted resin tran...

  16. Local Structure Fixation in the Composite Manufacturing Chain

    Science.gov (United States)

    Girdauskaite, Lina; Krzywinski, Sybille; Rödel, Hartmut; Wildasin-Werner, Andrea; Böhme, Ralf; Jansen, Irene

    2010-12-01

    Compared to metal materials, textile reinforced composites show interesting features, but also higher production costs because of low automation rate in the manufacturing chain at this time. Their applicability is also limited due to quality problems, which restrict the production of complex shaped dry textile preforms. New technologies, design concepts, and cost-effective manufacturing methods are needed in order to establish further fields of application. This paper deals with possible ways to improve the textile deformation process by locally applying a fixative to the structure parallel to the cut. This hinders unwanted deformation in the textile stock during the subsequent stacking and formation steps. It is found that suitable thermoplastic binders, applied in the appropriate manner do not restrict formation of the textile and have no negative influence on the mechanical properties of the composite.

  17. Composites

    International Nuclear Information System (INIS)

    Kasen, M.B.

    1983-01-01

    This chapter discusses the roles of composite laminates and aggregates in cryogenic technology. Filamentary-reinforced composites are emphasized because they are the most widely used composite materials. Topics considered include composite systems and terminology, design and fabrication, composite failure, high-pressure reinforced plastic laminates, low-pressure reinforced plastics, reinforced metals, selectively reinforced structures, the effect of cryogenic temperatures, woven-fabric and random-mat composites, uniaxial fiber-reinforced composites, composite joints in cryogenic structures, joining techniques at room temperature, radiation effects, testing laminates at cryogenic temperatures, static and cyclic tensile testing, static and cyclic compression testing, interlaminar shear testing, secondary property tests, and concrete aggregates. It is suggested that cryogenic composite technology would benefit from the development of a fracture mechanics model for predicting the fitness-for-purpose of polymer-matrix composite structures

  18. Concepts for the Design of a Diagnostic Device to Detect Malignancies in Human Tissues Final Report CRADA No. TSB-2023-00

    Energy Technology Data Exchange (ETDEWEB)

    DaSilva, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Marion, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chase, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-10-19

    BioLuminate, Inc. planned to develop, produce and market a revolutionary diagnostic device for early breast cancer diagnosis. The device was originally invented by NASA; and exclusively licensed to BioLuminate for commercialization. At the time of the CRADA, eighty-five percent (85%) of all biopsies in the United States were found negative each year. The number of biopsies cost the health care system $23 billio n annually. A multi-sensor probe would allow surgeons to improve breast cancer scre ening and significantly reduce the number of biopsies. BioLuminate was developing an in-vivo system for the detection of cancer using a multi-sensor needle/probe. The first system would be developed for the detection of breast cancer. LLNL, in collaboration with BioLuminate worked toward a detailed concept specification for the prototype multi-sensor needle/probe suitable for breast cancer analysis. BioLuminate in collaboration with LLNL, worked to develop a new version of the needle probe that would be the same size as needles commonly used to draw blood.

  19. Analysis of Sensory/Active Piezoelectric Composite Structures in Thermal Environments

    Science.gov (United States)

    Lee, Ho-Jun; Saravanos, Dimitris A.

    1996-01-01

    Although there has been extensive development of analytical methods for modeling the behavior of piezoelectric structures, only a limited amount of research has been performed concerning the implications of thermal effects on both the active and sensory response of smart structures. Thermal effects become important when the piezoelectric structure has to operate in either extremely hot or cold temperature environments. Consequently, the purpose of this paper is to extend the previously developed discrete layer formulation of Saravanos and Heyliger to account for the coupled mechanical, electrical, and thermal response in modern smart composite beams. The mechanics accounts for thermal effects which may arise in the elastic and piezoelectric media at the material level through the constitutive equations. The displacements, electric potentials, and temperatures are introduced as state variables, allowing them to be modeled as variable fields through the laminate thickness. This unified representation leads to an inherent capability to model both the active compensation of thermal distortions in smart structures and the resultant sensory voltage when thermal loads are applied. The corresponding finite element formulation is developed and numerical results demonstrate the ability to model both the active and sensory modes of composite beams with heterogeneous plies with attached piezoelectric layers under thermal loadings.

  20. Magnetic and structural characterizations on nanoparticles of FePt, FeRh and their composites

    International Nuclear Information System (INIS)

    Ko, Hnin Yu Yu; Suzuki, Takao; Nam, Nguyen T.; Phuoc, Nguyen N.; Cao Jiangwei; Hirotsu, Yoshihiko

    2008-01-01

    The various compositions of FePt and FeRh nanoparticles, and their composite particles have been fabricated by the solution-phase chemical method and their magnetic properties characterized. High-resolution transmission electron microscopic observations indicate that mono-dispersed FeRh and FePt/FeRh nanoparticles are fabricated with the average size of 3-5 nm. However, larger size particles are distributed in the annealed state. From X-ray diffraction results, the as-deposited FeRh nanoparticles reveal a chemically disordered fcc structure which can be transformed into CsCl-type structure through thermal annealing. Similarly, the annealed FePt nanoparticles show the L1 0 -phase fct structure although the fcc structure is apparent in the as-deposited state. It is also found that the first time in the exchange bias effect in the composite of ferromagnetic (FePt) and anti-ferromagnetic (FeRh) nanoparticles; result in a shift of the hysteresis loop after field cooling process

  1. Design of joints in steel and composite structures Eurocode 3 : design of steel structures : part 1-8 : design of joints, Eurocode 4 : design of composite steel and concrete structures : part 1-1 : general rules and rules for buildings

    CERN Document Server

    Jaspart, Jean-Pierre

    2016-01-01

    This book details the basic concepts and the design rules included in Eurocode 3 Design of steel structures Part 1-8 Design of joints. Joints in composite construction are also addressed through references to Eurocode 4 Design of composite steel and concrete structures Part 1-1 General rules and rules for buildings. Attention has to be duly paid to the joints when designing a steel or composite structure, in terms of the global safety of the construction, and also in terms of the overall cost, including fabrication, transportation and erection. Therefore, in this book, the design of the joints themselves is widely detailed, and aspects of selection of joint configuration and integration of the joints into the analysis and the design process of the whole construction are also fully covered. Connections using mechanical fasteners, welded connections, simple joints, moment-resisting joints and lattice girder joints are considered. Various joint configurations are treated, including beam-to-column, beam-to-beam, ...

  2. Monitoring of composite structures using a network of integrated PVDF film transducers

    International Nuclear Information System (INIS)

    Guzmán, Enrique; Cugnoni, Joël; Gmür, Thomas

    2015-01-01

    Aiming to reduce costs, polyvinylidene difluoride (PVDF) film patches are an emerging alternative to more classic piezoelectric technologies, like ceramic patches, as transducers to measure local deformation in many structural applications. This choice is supported by advantages such as the low weight and mechanical flexibility of PVDF, making this polymer suitable for embedding inside full scale polymer based composite structures. Piezoelectric transducer patches can be used as actuators to dynamically excite full-scale composite structures, and as sensors to measure the strain. The main objective of this paper is to verify that the PVDF transducers can provide exploitable signals in the context of structural health monitoring. In order to do so, two aspects of the design of transducer network are investigated: the optimization of the sensor network, for which the effective independence method is proposed, and the use of operational modal analysis (OMA), since it is a simple method to extract the natural frequencies of a structure from a time series. The results of the analysis are compared to a reference set issued from experimental modal analysis (EMA), a simple, well-known, classic method, which is carried out using accelerometers and an impact hammer. By statistical means, it is shown that there is no significant difference between the two methods, and an optimized PVDF transducer network combined with OMA can perform the dynamic analysis of a structure as well as a classic EMA setup would do. This leads the way to the use of low-cost PVDF embedded transducer networks for robust composite material characterization. (paper)

  3. Modal identification of composite structures using Eigen realization method

    International Nuclear Information System (INIS)

    Hamidzadeh, H.R.; Afolabi, D.

    1996-01-01

    Experimental modal analysis has proved to be a useful tool to determine the vibration response of complex composite structures. An accurate method for extracting modal parameters of these type of structures are presented. The method used experimental impulse response of the system as input and provides natural frequencies and damping ratios of a dynamic system. The employed theories are Eigen Realization and Impulse Response methods. The adopted method is superior to other available methods in time and frequency domains. The presented method is proven to provide robustness with respect to measured noise

  4. The shielding performance of multilayer composite shielding structures to 14.8 MeV fast neutrons

    International Nuclear Information System (INIS)

    Shen Zhiqiang; Kang Qing; Xu Jun; Wang Zhenggang; Lu Nan

    2014-01-01

    Cement-based round thin-layer samples mixed with 30% quality content of barite, and 20% quality content of carbide boron has Prepared, the same-diameter sliced samples of pure graphite and pure polyethylene has cut, then, samples combination and cross stack order has designed, formed four species Multilayer Composite shield structure, at last, neutron attenuation measurements has been done by experimental system of using 14.8 MeV neutrons from the 5SDH-2 accelerator and long counter composition, penetrating rate of samples and the shield structure to 14.8 MeV fast neutron has tested, and attenuation section has calculated. Results show that 14.8 MeV fast neutrons to higher penetration rates of thin layer samples, attenuation cross section of samples distinguish small between each other, must be increasing the thickness of the samples to reduce the experimental uncertainty; through composed of attenuation cross section and thickness parameters of composite structure, can more accurately predict the shielding ability of composite structures, error between calculation results and experimental results in 4%. (authors)

  5. Optical study on the dependence of breast tissue composition and structure on subject anamnesis

    Science.gov (United States)

    Taroni, Paola; Quarto, Giovanna; Pifferi, Antonio; Abbate, Francesca; Balestreri, Nicola; Menna, Simona; Cassano, Enrico; Cubeddu, Rinaldo

    2015-07-01

    Time domain multi-wavelength (635 to 1060 nm) optical mammography was performed on 200 subjects to estimate their average breast tissue composition in terms of oxy- and deoxy-hemoglobin, water, lipid and collagen, and structural information, as provided by scattering parameters (amplitude and power). Significant (and often marked) dependence of tissue composition and structure on age, menopausal status, body mass index, and use of oral contraceptives was demonstrated.

  6. Optimization Formulations for the Maximum Nonlinear Buckling Load of Composite Structures

    DEFF Research Database (Denmark)

    Lindgaard, Esben; Lund, Erik

    2011-01-01

    This paper focuses on criterion functions for gradient based optimization of the buckling load of laminated composite structures considering different types of buckling behaviour. A local criterion is developed, and is, together with a range of local and global criterion functions from literature......, benchmarked on a number of numerical examples of laminated composite structures for the maximization of the buckling load considering fiber angle design variables. The optimization formulations are based on either linear or geometrically nonlinear analysis and formulated as mathematical programming problems...... solved using gradient based techniques. The developed local criterion is formulated such it captures nonlinear effects upon loading and proves useful for both analysis purposes and as a criterion for use in nonlinear buckling optimization. © 2010 Springer-Verlag....

  7. Design of Electrically Conductive Structural Composites by Modulating Aligned CVD-Grown Carbon Nanotube Length on Glass Fibers.

    Science.gov (United States)

    He, Delong; Fan, Benhui; Zhao, Hang; Lu, Xiaoxin; Yang, Minhao; Liu, Yu; Bai, Jinbo

    2017-01-25

    Function-integration in glass fiber (GF) reinforced polymer composites is highly desired for developing lightweight structures and devices with improved performance and structural health monitoring. In this study, homogeneously aligned carbon nanotube (CNT) shell was in situ grafted on GF by chemical vapor deposition (CVD). It was demonstrated that the CNT shell thickness and weight fraction can be modulated by controlling the CVD conditions. The obtained hierarchical CNTs-GF/epoxy composites show highly improved electrical conductivity and thermo-mechanical and flexural properties. The composite through-plane and in-plane electrical conductivities increase from a quasi-isolator value to ∼3.5 and 100 S/m, respectively, when the weight fraction of CNTs grafted on GF fabric varies from 0% to 7%, respectively. Meanwhile, the composite storage modulus and flexural modulus and strength improve as high as 12%, 21%, and 26%, respectively, with 100% retention of the glass transition temperature. The reinforcing mechanisms are investigated by analyzing the composite microstructure and the interfacial adhesion and wetting properties of CNTs-GF hybrids. Moreover, the specific damage-related resistance variation characteristics could be employed to in situ monitor the structural health state of the composites. The outstanding electrical and structural properties of the CNTs-GF composites were due to the specific interfacial and interphase structures created by homogeneously grafting aligned CNTs on each GF of the fabric.

  8. Stochastic-Strength-Based Damage Simulation Tool for Ceramic Matrix and Polymer Matrix Composite Structures

    Science.gov (United States)

    Nemeth, Noel N.; Bednarcyk, Brett A.; Pineda, Evan J.; Walton, Owen J.; Arnold, Steven M.

    2016-01-01

    Stochastic-based, discrete-event progressive damage simulations of ceramic-matrix composite and polymer matrix composite material structures have been enabled through the development of a unique multiscale modeling tool. This effort involves coupling three independently developed software programs: (1) the Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC), (2) the Ceramics Analysis and Reliability Evaluation of Structures Life Prediction Program (CARES/ Life), and (3) the Abaqus finite element analysis (FEA) program. MAC/GMC contributes multiscale modeling capabilities and micromechanics relations to determine stresses and deformations at the microscale of the composite material repeating unit cell (RUC). CARES/Life contributes statistical multiaxial failure criteria that can be applied to the individual brittle-material constituents of the RUC. Abaqus is used at the global scale to model the overall composite structure. An Abaqus user-defined material (UMAT) interface, referred to here as "FEAMAC/CARES," was developed that enables MAC/GMC and CARES/Life to operate seamlessly with the Abaqus FEA code. For each FEAMAC/CARES simulation trial, the stochastic nature of brittle material strength results in random, discrete damage events, which incrementally progress and lead to ultimate structural failure. This report describes the FEAMAC/CARES methodology and discusses examples that illustrate the performance of the tool. A comprehensive example problem, simulating the progressive damage of laminated ceramic matrix composites under various off-axis loading conditions and including a double notched tensile specimen geometry, is described in a separate report.

  9. A single frequency component-based re-estimated MUSIC algorithm for impact localization on complex composite structures

    International Nuclear Information System (INIS)

    Yuan, Shenfang; Bao, Qiao; Qiu, Lei; Zhong, Yongteng

    2015-01-01

    The growing use of composite materials on aircraft structures has attracted much attention for impact monitoring as a kind of structural health monitoring (SHM) method. Multiple signal classification (MUSIC)-based monitoring technology is a promising method because of its directional scanning ability and easy arrangement of the sensor array. However, for applications on real complex structures, some challenges still exist. The impact-induced elastic waves usually exhibit a wide-band performance, giving rise to the difficulty in obtaining the phase velocity directly. In addition, composite structures usually have obvious anisotropy, and the complex structural style of real aircrafts further enhances this performance, which greatly reduces the localization precision of the MUSIC-based method. To improve the MUSIC-based impact monitoring method, this paper first analyzes and demonstrates the influence of measurement precision of the phase velocity on the localization results of the MUSIC impact localization method. In order to improve the accuracy of the phase velocity measurement, a single frequency component extraction method is presented. Additionally, a single frequency component-based re-estimated MUSIC (SFCBR-MUSIC) algorithm is proposed to reduce the localization error caused by the anisotropy of the complex composite structure. The proposed method is verified on a real composite aircraft wing box, which has T-stiffeners and screw holes. Three typical categories of 41 impacts are monitored. Experimental results show that the SFCBR-MUSIC algorithm can localize impact on complex composite structures with an obviously improved accuracy. (paper)

  10. Self-Supporting Nanoclay as Internal Scaffold Material for Direct Printing of Soft Hydrogel Composite Structures in Air.

    Science.gov (United States)

    Jin, Yifei; Liu, Chengcheng; Chai, Wenxuan; Compaan, Ashley; Huang, Yong

    2017-05-24

    Three dimensional (3D) bioprinting technology enables the freeform fabrication of complex constructs from various hydrogels and is receiving increasing attention in tissue engineering. The objective of this study is to develop a novel self-supporting direct hydrogel printing approach to extrude complex 3D hydrogel composite structures in air without the help of a support bath. Laponite, a member of the smectite mineral family, is investigated to serve as an internal scaffold material for the direct printing of hydrogel composite structures in air. In the proposed printing approach, due to its yield-stress property, Laponite nanoclay can be easily extruded through a nozzle as a liquid and self-supported after extrusion as a solid. Its unique crystal structure with positive and negative charges enables it to be mixed with many chemically and physically cross-linked hydrogels, which makes it an ideal internal scaffold material for the fabrication of various hydrogel structures. By mixing Laponite nanoclay with various hydrogel precursors, the hydrogel composites retain their self-supporting capacity and can be printed into 3D structures directly in air and retain their shapes before cross-linking. Then, the whole structures are solidified in situ by applying suitable cross-linking stimuli. The addition of Laponite nanoclay can effectively improve the mechanical and biological properties of hydrogel composites. Specifically, the addition of Laponite nanoclay results in a significant increase in the Young's modulus of each hydrogel-Laponite composite: 1.9-fold increase for the poly(ethylene glycol) diacrylate (PEGDA)-Laponite composite, 7.4-fold increase for the alginate-Laponite composite, and 3.3-fold increase for the gelatin-Laponite composite.

  11. Design of a composite structure to achieve a specified reliability level

    International Nuclear Information System (INIS)

    Boyer, C.; Beakou, A.; Lemaire, M.

    1997-01-01

    Safety factors are widely used in structural design. For composite material structures, however, the lack of experimental feed-back does not allow the use of safety factors optimized from cost and reliability point of view. Reliability methods are one way to achieve the calibration of partial safety factors using a more rational method than judgement alone. First we present the calibration process. The reliability methods FORM, SORM, simulation, are initially applied to a laminate plate under uniform pressure. In this example, we compare three design criteria; the different reliability methods agree with the reference method for all criteria used. We chose the Tsai-Hill criteria and the FORM method to calculate safety factors. Then, a calibration process is undertaken on a composite pipe and this serves to illustrate the different steps in the calculation. Finally, we present a calibration of a general plate structure. The partial safety factors and their sensitivities to the different parameters of the stochastic variables are given according to load type

  12. Persistence of urban organic aerosols composition: Decoding their structural complexity and seasonal variability

    International Nuclear Information System (INIS)

    Matos, João T.V.; Duarte, Regina M.B.O.; Lopes, Sónia P.; Silva, Artur M.S.; Duarte, Armando C.

    2017-01-01

    Organic Aerosols (OAs) are typically defined as highly complex matrices whose composition changes in time and space. Focusing on time vector, this work uses two-dimensional nuclear magnetic resonance (2D NMR) techniques to examine the structural features of water-soluble (WSOM) and alkaline-soluble organic matter (ASOM) sequentially extracted from fine atmospheric aerosols collected in an urban setting during cold and warm seasons. This study reveals molecular signatures not previously decoded in NMR-related studies of OAs as meaningful source markers. Although the ASOM is less hydrophilic and structurally diverse than its WSOM counterpart, both fractions feature a core with heteroatom-rich branched aliphatics from both primary (natural and anthropogenic) and secondary origin, aromatic secondary organics originated from anthropogenic aromatic precursors, as well as primary saccharides and amino sugar derivatives from biogenic emissions. These common structures represent those 2D NMR spectral signatures that are present in both seasons and can thus be seen as an “annual background” profile of the structural composition of OAs at the urban location. Lignin-derived structures, nitroaromatics, disaccharides, and anhydrosaccharides signatures were also identified in the WSOM samples only from periods identified as smoke impacted, which reflects the influence of biomass-burning sources. The NMR dataset on the H–C molecules backbone was also used to propose a semi-quantitative structural model of urban WSOM, which will aid efforts for more realistic studies relating the chemical properties of OAs with their atmospheric behavior. - Highlights: • 2D NMR spectroscopy was used to decode urban organic aerosols. • Water and alkaline soluble components of urban organic aerosols have been compared. • Persistence of urban organic aerosols composition across different seasons. • Annual background profile of the structural features of urban organic aerosols. • Semi

  13. Structure recognition from high resolution images of ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Ushizima, Daniela; Perciano, Talita; Krishnan, Harinarayan; Loring, Burlen; Bale, Hrishikesh; Parkinson, Dilworth; Sethian, James

    2015-01-05

    Fibers provide exceptional strength-to-weight ratio capabilities when woven into ceramic composites, transforming them into materials with exceptional resistance to high temperature, and high strength combined with improved fracture toughness. Microcracks are inevitable when the material is under strain, which can be imaged using synchrotron X-ray computed micro-tomography (mu-CT) for assessment of material mechanical toughness variation. An important part of this analysis is to recognize fibrillar features. This paper presents algorithms for detecting and quantifying composite cracks and fiber breaks from high-resolution image stacks. First, we propose recognition algorithms to identify the different structures of the composite, including matrix cracks and fibers breaks. Second, we introduce our package F3D for fast filtering of large 3D imagery, implemented in OpenCL to take advantage of graphic cards. Results show that our algorithms automatically identify micro-damage and that the GPU-based implementation introduced here takes minutes, being 17x faster than similar tools on a typical image file.

  14. Using thin metal layers on composite structures for shielding the electromagnetic pulse caused by nearby lightning

    NARCIS (Netherlands)

    Blaj, M.A.; Buesink, Frederik Johannes Karel; Damstra, G.C.; Leferink, Frank Bernardus Johannes

    2011-01-01

    Electronic systems in composite structures could be vulnerable to the (dominant magnetic) field caused by a lightning strike, because only thin layers of metal can be used on composite structures. Thin layers result in a very low shielding effectiveness against magnetic fields. Many experiments

  15. The Manufacturing Process for the NASA Composite Crew Module Demonstration Structure

    Science.gov (United States)

    Pelham, Larry; Higgins, John E.

    2008-01-01

    This paper will describe the approaches and methods selected in fabrication of a carbon composite demonstration structure for the Composite Crew Module (CCM) Program. The program is managed by the NASA Safety and Engineering Center with participants from ten NASA Centers and AFRL. Multiple aerospace contractors are participating in the design development, tooling and fabrication effort as well. The goal of the program is to develop an agency wide design team for composite habitable spacecraft. The specific goals for this development project are: a).To gain hands on experience in design, building and testing a composite crew module. b) To validate key assumptions by resolving composite spacecraft design details through fabrication and testing of hardware. This abstract is based on Preliminary Design data..The final design will continue to evolve through the fall of 2007 with fabrication mostly completed by conference date. From a structures perspective, the.CCM can be viewed as a pressure module with variable pressure time histories and a series of both impact and quasi-static, high intensity point, line, and area distributed loads. The portion of the overall space vehicle being designed and. fabricated by the CCM team is just the pressure module and primary loading points. The heaviest point loads are applied and distributed to the pressure module at.an aluminum Service Module/Alternate Launch Abort System (SM/ALAS) fittings and at Main and Drogue Chute fittings. Significant line loads with metal to metal impact is applied at.the Lids ring. These major external point and line loads as well as pressure impact loads (blast and water landing) are applied to the lobed floor though the reentry shield and crushable materials. The pressure module is divided into upper and lower. shells that mate together with a bonded belly band splice joint to create the completed structural assembly. The benefits of a split CCM far outweigh the risks of a joint. These benefits include

  16. Radiation-induced structural transitions in composite materials with strong interaction of polymer components

    International Nuclear Information System (INIS)

    Zaikin, Yu.A.; Koztaeva, U.P.

    2002-01-01

    In earlier papers the internal friction (IF) method was applied to studies of structural relaxation in different types of polymer-based composite materials (glass-cloth, paper-based and foiled laminates impregnated by epoxy and phenolic resins) irradiated by 2 MeV electrons in the dose range of 0.1-50.0 MGy. Selectivity and high sensibility of the internal friction method allowed to distinguish glassy transitions in different structural components of the composites. The relaxation processes observed were identified and attributed to structural alterations in the polymer filler, the binder and the boundary layers. It was shown that changes in the parameters of relaxation maximums during irradiation can be considered as quantitative characteristics for the degree of radiation-induced degradation or cross-linking of polymer molecules. This paper deals with specific features of IF spectra in paper-based laminates where both the filler fibers and the binder are strongly interacting polymers. Anisotropy of viscous and elastic properties is very weak for this kind of materials, so that IF measurements give nearly the same result independently on the filler fiber orientation in the sample. The main reasons for it are the rigid chain structure of fillers (polyethylene-terephthalate and cellulose) and the good adhesion strengthened by diffusion of the epoxy or phenolic binder to defect regions of the filler.The IF temperature dependence observed in paper-based laminates is represented by superposition of two very broad relaxation maximums associated with transitions from glassy to high-elastic state in structural components, each based on one of the polymers. The inflection points characteristic for IF temperature dependence in paper-based laminates give a reason to treat them as a superposition of α-peaks associated with transitions from glassy to high-elastic state in structural components of a composite based on the binder and the filler, respectively. Another

  17. Fuzzy Reasoning to More Accurately Determine Void Areas on Optical Micrographs of Composite Structures

    Science.gov (United States)

    Dominquez, Jesus A.; Tate, Lanetra C.; Wright, M. Clara; Caraccio, Anne

    2013-01-01

    Accomplishing the best-performing composite matrix (resin) requires that not only the processing method but also the cure cycle generate low-void-content structures. If voids are present, the performance of the composite matrix will be significantly reduced. This is usually noticed by significant reductions in matrix-dominated properties, such as compression and shear strength. Voids in composite materials are areas that are absent of the composite components: matrix and fibers. The characteristics of the voids and their accurate estimation are critical to determine for high performance composite structures. One widely used method of performing void analysis on a composite structure sample is acquiring optical micrographs or Scanning Electron Microscope (SEM) images of lateral sides of the sample and retrieving the void areas within the micrographs/images using an image analysis technique. Segmentation for the retrieval and subsequent computation of void areas within the micrographs/images is challenging as the gray-scaled values of the void areas are close to the gray-scaled values of the matrix leading to the need of manually performing the segmentation based on the histogram of the micrographs/images to retrieve the void areas. The use of an algorithm developed by NASA and based on Fuzzy Reasoning (FR) proved to overcome the difficulty of suitably differentiate void and matrix image areas with similar gray-scaled values leading not only to a more accurate estimation of void areas on composite matrix micrographs but also to a faster void analysis process as the algorithm is fully autonomous.

  18. Variability in Parasites' Community Structure and Composition in Cat ...

    African Journals Online (AJOL)

    This study investigated the composition and structure of the parasite communities in Cat fish with respect to levels of water pollution in Lake Victoria. A total of 1071 Clarias gariepinus with mean TL range of 19 to 27 cm were analyzed from three localities in Mwanza Gulf (Kirumba, 298 fish infected with 15 parasite species), ...

  19. Performance improvement of silicon nitride ball bearings by ion implantation. CRADA final report

    International Nuclear Information System (INIS)

    Williams, J.M.; Miner, J.

    1998-01-01

    The present report summarizes technical results of CRADA No. ORNL 92-128 with the Pratt and Whitney Division of United Technologies Corporation. The stated purpose of the program was to assess the 3effect of ion implantation on the rolling contact performance of engineering silicon nitride bearings, to determine by post-test analyses of the bearings the reasons for improved or reduced performance and the mechanisms of failure, if applicable, and to relate the overall results to basic property changes including but not limited to swelling, hardness, modulus, micromechanical properties, and surface morphology. Forty-two control samples were tested to an intended runout period of 60 h. It was possible to supply only six balls for ion implantation, but an extended test period goal of 150 h was used. The balls were implanted with C-ions at 150 keV to a fluence of 1.1 x 10 17 /cm 2 . The collection of samples had pre-existing defects called C-cracks in the surfaces. As a result, seven of the control samples had severe spalls before reaching the goal of 60 h for an unacceptable failure rate of 0.003/sample-h. None of the ion-implanted samples experienced engineering failure in 150 h of testing. Analytical techniques have been used to characterize ion implantation results, to characterize wear tracks, and to characterize microstructure and impurity content. In possible relation to C-cracks. It is encouraging that ion implantation can mitigate the C-crack failure mode. However, the practical implications are compromised by the fact that bearings with C-cracks would, in no case, be acceptable in engineering practice, as this type of defect was not anticipated when the program was designed. The most important reason for the use of ceramic bearings is energy efficiency

  20. Population Structure and Genomic Breed Composition in an Angus-Brahman Crossbred Cattle Population.

    Science.gov (United States)

    Gobena, Mesfin; Elzo, Mauricio A; Mateescu, Raluca G

    2018-01-01

    Crossbreeding is a common strategy used in tropical and subtropical regions to enhance beef production, and having accurate knowledge of breed composition is essential for the success of a crossbreeding program. Although pedigree records have been traditionally used to obtain the breed composition of crossbred cattle, the accuracy of pedigree-based breed composition can be reduced by inaccurate and/or incomplete records and Mendelian sampling. Breed composition estimation from genomic data has multiple advantages including higher accuracy without being affected by missing, incomplete, or inaccurate records and the ability to be used as independent authentication of breed in breed-labeled beef products. The present study was conducted with 676 Angus-Brahman crossbred cattle with genotype and pedigree information to evaluate the feasibility and accuracy of using genomic data to determine breed composition. We used genomic data in parametric and non-parametric methods to detect population structure due to differences in breed composition while accounting for the confounding effect of close familial relationships. By applying principal component analysis (PCA) and the maximum likelihood method of ADMIXTURE to genomic data, it was possible to successfully characterize population structure resulting from heterogeneous breed ancestry, while accounting for close familial relationships. PCA results offered additional insight into the different hierarchies of genetic variation structuring. The first principal component was strongly correlated with Angus-Brahman proportions, and the second represented variation within animals that have a relatively more extended Brangus lineage-indicating the presence of a distinct pattern of genetic variation in these cattle. Although there was strong agreement between breed proportions estimated from pedigree and genetic information, there were significant discrepancies between these two methods for certain animals. This was most likely due

  1. Population Structure and Genomic Breed Composition in an Angus–Brahman Crossbred Cattle Population

    Directory of Open Access Journals (Sweden)

    Mesfin Gobena

    2018-03-01

    Full Text Available Crossbreeding is a common strategy used in tropical and subtropical regions to enhance beef production, and having accurate knowledge of breed composition is essential for the success of a crossbreeding program. Although pedigree records have been traditionally used to obtain the breed composition of crossbred cattle, the accuracy of pedigree-based breed composition can be reduced by inaccurate and/or incomplete records and Mendelian sampling. Breed composition estimation from genomic data has multiple advantages including higher accuracy without being affected by missing, incomplete, or inaccurate records and the ability to be used as independent authentication of breed in breed-labeled beef products. The present study was conducted with 676 Angus–Brahman crossbred cattle with genotype and pedigree information to evaluate the feasibility and accuracy of using genomic data to determine breed composition. We used genomic data in parametric and non-parametric methods to detect population structure due to differences in breed composition while accounting for the confounding effect of close familial relationships. By applying principal component analysis (PCA and the maximum likelihood method of ADMIXTURE to genomic data, it was possible to successfully characterize population structure resulting from heterogeneous breed ancestry, while accounting for close familial relationships. PCA results offered additional insight into the different hierarchies of genetic variation structuring. The first principal component was strongly correlated with Angus–Brahman proportions, and the second represented variation within animals that have a relatively more extended Brangus lineage—indicating the presence of a distinct pattern of genetic variation in these cattle. Although there was strong agreement between breed proportions estimated from pedigree and genetic information, there were significant discrepancies between these two methods for certain animals

  2. Analysis of Textile Composite Structures Subjected to High Temperature Oxidizing Environment

    Science.gov (United States)

    2010-08-01

    process in a polymer is a combination of the diffusion of oxygen and its consumption by reaction, which also results in the creation of by-products...based on the work by Pochiraju et al[24-26] in which they used the conservation of mass law for diffusion with a term to model the rate of consumption ...Oxidation of C/SiC Composites, Proceedings of the 21st Annual Conference on Composites, Advanced Ceramics Materials and Structures, Cocoa Beach

  3. Structural investigation of composite wind turbine blade considering various load cases and fatigue life

    International Nuclear Information System (INIS)

    Kong, C.; Bang, J.; Sugiyama, Y.

    2005-01-01

    This study proposes a structural design for developing a medium scale composite wind turbine blade made of E-glass/epoxy for a 750 kW class horizontal axis wind turbine system. The design loads were determined from various load cases specified at the IEC61400-1 international specification and GL regulations for the wind energy conversion system. A specific composite structure configuration, which can effectively endure various loads such as aerodynamic loads and loads due to accumulation of ice, hygro-thermal and mechanical loads, was proposed. To evaluate the proposed composite wind turbine blade, structural analysis was performed by using the finite element method. Parametric studies were carried out to determine an acceptable blade structural design, and the most dominant design parameters were confirmed. In this study, the proposed blade structure was confirmed to be safe and stable under various load conditions, including the extreme load conditions. Moreover, the blade adapted a new blade root joint with insert bolts, and its safety was verified at design loads including fatigue loads. The fatigue life of a blade that has to endure for more than 20 years was estimated by using the well-known S-N linear damage theory, the service load spectrum, and the Spera's empirical equations. With the results obtained from all the structural design and analysis, prototype composite blades were manufactured. A specific construction process including the lay-up molding method was applied to manufacturing blades. Full-scale static structural test was performed with the simulated aerodynamic loads. From the experimental results, it was found that the designed blade had structural integrity. In addition, the measured results of deflections, strains, mass, and radial center of gravity agreed well with the analytical results. The prototype blade was successfully certified by an international certification institute, GL (Germanisher Lloyd) in Germany

  4. Facile Synthesis of Yolk/Core-Shell Structured TS-1@Mesosilica Composites for Enhanced Hydroxylation of Phenol

    KAUST Repository

    Zou, Houbing

    2015-12-14

    © 2015 by the authors. In the current work, we developed a facile synthesis of yolk/core-shell structured TS-1@mesosilica composites and studied their catalytic performances in the hydroxylation of phenol with H2O2 as the oxidant. The core-shell TS-1@mesosilica composites were prepared via a uniform coating process, while the yolk-shell TS-1@mesosilica composite was prepared using a resorcinol-formaldehyde resin (RF) middle-layer as the sacrificial template. The obtained materials were characterized by X-ray diffraction (XRD), N2 sorption, Fourier transform infrared spectoscopy (FT-IR) UV-Visible spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The characterization results showed that these samples possessed highly uniform yolk/core-shell structures, high surface area (560–700 m2 g−1) and hierarchical pore structures from oriented mesochannels to zeolite micropores. Importantly, owing to their unique structural properties, these composites exhibited enhanced activity, and also selectivity in the phenol hydroxylation reaction.

  5. Fatigue degradation and failure of rotating composite structures - Materials characterisation and underlying mechanisms

    DEFF Research Database (Denmark)

    Gamstedt, Kristofer; Andersen, Svend Ib Smidt

    2001-01-01

    The present review concerns rotating composite structures, in which fatigue degradation is of key concern for in-service failure. Such applications are for instance rotor blades in wind turbines, helicopter rotor blades, flywheels for energy storage,marine and aeronautical propellers, and rolls...... for paper machines. The purpose is to identify areas where impending efforts should be made to make better use of composite materials in these applications. In order to obtain better design methodologies,which would allow more reliable and slender structures, improved test methods are necessary. Furthermore...

  6. Carbon fiber polymer-matrix structural composites tailored for multifunctionality by filler incorporation

    Science.gov (United States)

    Han, Seungjin

    This dissertation provides multifunctional carbon fiber polymer-matrix structural composites for vibration damping, thermal conduction and thermoelectricity. Specifically, (i) it has strengthened and stiffened carbon fiber polymer-matrix structural composites by the incorporation of halloysite nanotubes, carbon nanotubes and silicon carbide whiskers, (ii) it has improved mechanical energy dissipation using carbon fiber polymer-matrix structural composites with filler incorporation, (iii) it has increased the through-thickness thermal conductivity of carbon fiber polymer-matrix composite by curing pressure increase and filler incorporation, and (iv) it has enhanced the thermoelectric behavior of carbon fiber polymer-matrix structural composites. Low-cost natural halloysite nanotubes (0.1 microm diameter) were effective for strengthening and stiffening continuous fiber polymer-matrix composites, as shown for crossply carbon fiber (5 microm diameter, ˜59 vol.%) epoxy-matrix composites under flexure, giving 17% increase in strength, 11% increase in modulus and 21% decrease in ductility. They were less effective than expensive multiwalled carbon nanotubes (0.02 microm diameter), which gave 25% increase in strength, 11% increase in modulus and 14% decrease in ductility. However, they were more effective than expensive silicon carbide whiskers (1 microm diameter), which gave 15% increase in strength, 9% increase in modulus and 20% decrease in ductility. Each filler, at ˜2 vol.%, was incorporated in the composite at every interlaminar interface by fiber prepreg surface modification. The flexural strength increase due to halloysite nanotubes incorporation related to the interlaminar shear strength increase. The measured values of the composite modulus agreed roughly with the calculated values based on the Rule of Mixtures. Continuous carbon fiber composites with enhanced vibration damping under flexure are provided by incorporation of fillers between the laminae

  7. Standard practice for acoustic emission examination of plate-like and flat panel composite structures used in aerospace applications

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice covers acoustic emission (AE) examination or monitoring of panel and plate-like composite structures made entirely of fiber/polymer composites. 1.2 The AE examination detects emission sources and locates the region(s) within the composite structure where the emission originated. When properly developed AE-based criteria for the composite item are in place, the AE data can be used for nondestructive examination (NDE), characterization of proof testing, documentation of quality control or for decisions relative to structural-test termination prior to completion of a planned test. Other NDE methods may be used to provide additional information about located damage regions. For additional information see Appendix X1. 1.3 This practice can be applied to aerospace composite panels and plate-like elements as a part of incoming inspection, during manufacturing, after assembly, continuously (during structural health monitoring) and at periodic intervals during the life of a structure. 1.4 This pra...

  8. Structure and characteristics of the hot pressed hydroxyapatite/poly-L-lactide composite

    Directory of Open Access Journals (Sweden)

    Ignjatović Nenad L.

    2002-01-01

    Full Text Available Hydroxyapatite/poly-L-lactide (HAp/PLL composite biomaterial can be obtained by different processing methods. Three-dimensional blocks of HAp/PLLA composite biomaterial with mechanical characteristics close to the natural bone tissue can be obtained by hot pressing procedure. Effects of synthesis and compacting on the structure and characteristics of the HAp/PLLA composite biomaterial were studied in this work. Using wade angle X-ray structural analyses (WAXS, differentially scanning calorimetry (DSC, thermogravimetric analysis (TGA and infrared (IR spectroscopy, the changes occurring in the material during synthesis and hot pressing were monitored. Surface microstructure was analyzed by scanning electronic microscopy (SEM coupled with electron-dispersion analysis (EDX. The results obtained indicate a possible decrease in the degree of crystallinity with hot pressing time increase. A block of HAp/PLLA composite biomaterial with 1.6 times lower crystallinity of the polymer phase was obtained by hot pressing in a given time interval with a maximum of 60 minutes. Results of TG analysis show that PLLA stability decreases with increasing hot pressing time, and vice versa. IR study proved that neither destructive changes in constituents nor formation of new phases occurred during hot pressing.

  9. An overview of the crash dynamics failure behavior of metal and composite aircraft structures

    Science.gov (United States)

    Carden, Huey D.; Boitnott, Richard L.; Fasanella, Edwin L.; Jones, Lisa E.

    1991-01-01

    An overview of failure behavior results is presented from some of the crash dynamics research conducted with concepts of aircraft elements and substructure not necessarily designed or optimized for energy absorption or crash loading considerations. Experimental and analytical data are presented that indicate some general trends in the failure behavior of a class of composite structures that includes fuselage panels, individual fuselage sections, fuselage frames, skeleton subfloors with stringers and floor beams without skin covering, and subfloors with skin added to the frame stringer structure. Although the behavior is complex, a strong similarity in the static/dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical data of generic composite structural models.

  10. Fiber Bragg Grating Sensor System for Monitoring Smart Composite Aerospace Structures

    Science.gov (United States)

    Moslehi, Behzad; Black, Richard J.; Gowayed, Yasser

    2012-01-01

    Lightweight, electromagnetic interference (EMI) immune, fiber-optic, sensor- based structural health monitoring (SHM) will play an increasing role in aerospace structures ranging from aircraft wings to jet engine vanes. Fiber Bragg Grating (FBG) sensors for SHM include advanced signal processing, system and damage identification, and location and quantification algorithms. Potentially, the solution could be developed into an autonomous onboard system to inspect and perform non-destructive evaluation and SHM. A novel method has been developed to massively multiplex FBG sensors, supported by a parallel processing interrogator, which enables high sampling rates combined with highly distributed sensing (up to 96 sensors per system). The interrogation system comprises several subsystems. A broadband optical source subsystem (BOSS) and routing and interface module (RIM) send light from the interrogation system to a composite embedded FBG sensor matrix, which returns measurand-dependent wavelengths back to the interrogation system for measurement with subpicometer resolution. In particular, the returned wavelengths are channeled by the RIM to a photonic signal processing subsystem based on powerful optical chips, then passed through an optoelectronic interface to an analog post-detection electronics subsystem, digital post-detection electronics subsystem, and finally via a data interface to a computer. A range of composite structures has been fabricated with FBGs embedded. Stress tensile, bending, and dynamic strain tests were performed. The experimental work proved that the FBG sensors have a good level of accuracy in measuring the static response of the tested composite coupons (down to submicrostrain levels), the capability to detect and monitor dynamic loads, and the ability to detect defects in composites by a variety of methods including monitoring the decay time under different dynamic loading conditions. In addition to quasi-static and dynamic load monitoring, the

  11. Effects of heat treatment on optical absorption properties of Ni-P/AAO nano-array composite structure

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yi-Fan; Wang, Feng-Hua; Guo, Dong-Lai; Huang, Sheng-You; Zou, Xian-Wu [Wuhan University, Department of Physics, Wuhan (China); Sang, Jian-Ping [Wuhan University, Department of Physics, Wuhan (China); Jianghan University, Department of Physics, Wuhan (China)

    2009-11-15

    Ni-P/AAO nano-array composite structure assemblies with Ni and P grown in the pores of anodic aluminum oxide (AAO) membranes were prepared by electroless deposition. The results of SEM, TEM and SAED show that as-deposited Ni-P nanowires have an amorphous structure and a few nanocrystallites form after annealing. The optical absorption spectra reveal that, as the annealing temperature increases, the absorption band edge of the Ni-P/AAO composite structure is obviously blue shifted, which is attributed to a decrease of the internal pressure after heat treatment. Meanwhile, the annealed Ni-P/AAO nano-array composite structure exhibits the absorption behavior of a direct band gap semiconductor. Details of this behavior are discussed together with the implications for potential device applications. (orig.)

  12. Active control of structures using macro-fiber composite (MFC)

    International Nuclear Information System (INIS)

    Kovalovs, A; Barkanov, E; Gluhihs, S

    2007-01-01

    This paper presents the use of macro-fiber composites (MFC) for vibration reduces of structures. The MFC consist of polyimid films with IDE-electrodes that are glued on the top and the bottom of rectangular piezoceramic fibers. The interdigitated electrodes deliver the electric field required to activate the piezoelectric effect in the fibers and allows to invoke the stronger longitudinal piezoelectric effect along the length of the fibers. When this actuator embedded in a surface or attached to flexible structures, the MFC actuator provides distributed solid-state deflection and vibration control. The major advantages of the piezoelectric fibre composite actuators are their high performance, flexibility, and durability when compared with the traditional piezoceramic (PZT) actuators. In addition, the ability of MFC devices to couple the electrical and mechanical fields is larger than in monolithic PZT. In this study, we showed the experimental results that an MFC could be used as actuator to find modal parameters and reduce vibration for structures such as an aluminium beam and metal music plate. Two MFC actuators were attached to the surfaces of test subjects. First MFC actuator used to supply a signal as exciter of vibration and second MFC show his application for reduction of vibration in the range of resonance frequencies. Experimental results of aluminium beam with MFC actuators compared with finite element model which modelled in ANSYS software. The applied voltage is modelled as a thermal load according to thermal analogy for MFC. The experimental and numerical results presented in this paper confirm the potential of MFC for use in the vibration control of structures

  13. Active control of structures using macro-fiber composite (MFC)

    Energy Technology Data Exchange (ETDEWEB)

    Kovalovs, A; Barkanov, E; Gluhihs, S [Institute of Materials and Structures, Riga Technical University, 16/20 Azenes Str., Riga, LV-1048 (Latvia)

    2007-12-15

    This paper presents the use of macro-fiber composites (MFC) for vibration reduces of structures. The MFC consist of polyimid films with IDE-electrodes that are glued on the top and the bottom of rectangular piezoceramic fibers. The interdigitated electrodes deliver the electric field required to activate the piezoelectric effect in the fibers and allows to invoke the stronger longitudinal piezoelectric effect along the length of the fibers. When this actuator embedded in a surface or attached to flexible structures, the MFC actuator provides distributed solid-state deflection and vibration control. The major advantages of the piezoelectric fibre composite actuators are their high performance, flexibility, and durability when compared with the traditional piezoceramic (PZT) actuators. In addition, the ability of MFC devices to couple the electrical and mechanical fields is larger than in monolithic PZT. In this study, we showed the experimental results that an MFC could be used as actuator to find modal parameters and reduce vibration for structures such as an aluminium beam and metal music plate. Two MFC actuators were attached to the surfaces of test subjects. First MFC actuator used to supply a signal as exciter of vibration and second MFC show his application for reduction of vibration in the range of resonance frequencies. Experimental results of aluminium beam with MFC actuators compared with finite element model which modelled in ANSYS software. The applied voltage is modelled as a thermal load according to thermal analogy for MFC. The experimental and numerical results presented in this paper confirm the potential of MFC for use in the vibration control of structures.

  14. Synthesis, Structural, and Adsorption Properties and Thermal Stability of Nanohydroxyapatite/Polysaccharide Composites.

    Science.gov (United States)

    Skwarek, Ewa; Goncharuk, Olena; Sternik, Dariusz; Janusz, Wladyslaw; Gdula, Karolina; Gun'ko, Vladimir M

    2017-12-01

    A series of composites based on nanohydroxyapatite (nHAp) and natural polysaccharides (PS) (nHAp/agar, nHAp/chitosan, nHAp/pectin FB300, nHAp/pectin APA103, nHAp/sodium alginate) was synthesized by liquid-phase two-step method and characterized using nitrogen adsorption-desorption, DSC, TG, FTIR spectroscopy, and SEM. The analysis of nitrogen adsorption-desorption data shows that composites with a nHAp: PS ratio of 4:1 exhibit a sufficiently high specific surface area from 49 to 82 m 2 /g. The incremental pore size distributions indicate mainly mesoporosity. The composites with the component ratio 1:1 preferably form a film-like structure, and the value of S BET varies from 0.3 to 43 m 2 /g depending on the nature of a polysaccharide. Adsorption of Sr(II) on the composites from the aqueous solutions has been studied. The thermal properties of polysaccharides alone and in nHAp/PS show the influence of nHAp, since there is a shift of characteristic DSC and DTG peaks. FTIR spectroscopy data confirm the presence of functional groups typical for nHAp as well as polysaccharides in composites. Structure and morphological characteristics of the composites are strongly dependent on the ratio of components, since nHAp/PS at 4:1 have relatively large S BET values and a good ability to adsorb metal ions. The comparison of the adsorption capacity with respect to Sr(II) of nHAp, polysaccharides, and composites shows that it of the latter is higher than that of nHAp (per 1 m 2 of surface).

  15. composition and size class structure of tree species in ihang'ana

    African Journals Online (AJOL)

    nb

    Previous plant biodiversity studies in this ecosystem concentrated on large-sized Forest ... assess tree species composition, structure and diversity in Ihang'ana FR (2982 ha), one of the ..... Dombeya rotundifolia. (Hochst) ... Ficus lutea. Vahl.

  16. 77 FR 38770 - Notice of Consortium on “nSoft Consortium”

    Science.gov (United States)

    2012-06-29

    ... Development Agreement (``CRADA'') with NIST. Membership is limited to 40 for-profit institutions and 15 not... by Member to NIST at the time of CRADA execution and annually in August thereafter. For-profit... Thousand ($10,000), payable at the time of CRADA execution. Subsequent membership payments of Twenty...

  17. 77 FR 25488 - Cooperative Research and Development Agreement: Federally Integrated Communications System

    Science.gov (United States)

    2012-04-30

    ... Cooperative Research and Development Agreement (CRADA) with General Dynamics C4 Systems, Inc. to lab.... The Coast Guard invites public comment on the proposed CRADA, and also invites other potential non... material on the proposed CRADA must either be submitted to our online docket via http://www.regulations.gov...

  18. Effect of dielectrophoretic structuring on piezoelectric and pyroelectric properties of lead titanate-epoxy composites

    NARCIS (Netherlands)

    Khanbareh, H.; Zwaag, S. van der; Groen, W.A.

    2014-01-01

    Functional granular composites of lead titanate particles in an epoxy matrix prepared by dielectrophoresis show enhanced dielectric, piezoelectric and pyroelectric properties compared to 0-3 composites for different ceramic volume content from 10% to 50%. Two structuring parameters, the

  19. Spinning, structure and properties of PP/CNTs and PP/carbon black composite fibers

    Science.gov (United States)

    Marcincin, A.; Hricova, M.; Ujhelyiova, A.

    2014-08-01

    In this paper, the effect of the compatibilisers-dispersants and other nanofillers on melt spinning of the polypropylene (PP) composites, containing carbon nanotubes (CNTs), and carbon black pigment (CBP) has been investigated. Further, the structure and selected properties of composite fibers, such as mechanical and electrical have been studied. The results revealed, that percolation threshold for PP/CBP composite fibres was situated within the concentration of 15 - 20 wt%, what is several times higher than for PP/CNTs fibers.

  20. Preparation and properties of GO-PVA composite hydrogel with oriented structure

    Science.gov (United States)

    Liu, Huanqing; Zhang, Gongzheng; Li, Huanjun

    2017-03-01

    We fabricated GO-PVA composite hydrogels with oriented structure by directional freezing and repeated freeze-thawing, which owned superior mechanical property and thermostability than PVA hydrogel. Due to physical interactions such as hydrogen bonding between surface of GO and PVA chains, GO-PVA composite hydrogel possessed higher crosslinking density and smaller pore size and can resist higher temperature and stronger force from outside than PVA hydrogel. These unique properties will endow GO-PVA hydrogel with greater potential application in biomedical materials.

  1. Representing general theoretical concepts in structural equation models: The role of composite variables

    Science.gov (United States)

    Grace, J.B.; Bollen, K.A.

    2008-01-01

    Structural equation modeling (SEM) holds the promise of providing natural scientists the capacity to evaluate complex multivariate hypotheses about ecological systems. Building on its predecessors, path analysis and factor analysis, SEM allows for the incorporation of both observed and unobserved (latent) variables into theoretically-based probabilistic models. In this paper we discuss the interface between theory and data in SEM and the use of an additional variable type, the composite. In simple terms, composite variables specify the influences of collections of other variables and can be helpful in modeling heterogeneous concepts of the sort commonly of interest to ecologists. While long recognized as a potentially important element of SEM, composite variables have received very limited use, in part because of a lack of theoretical consideration, but also because of difficulties that arise in parameter estimation when using conventional solution procedures. In this paper we present a framework for discussing composites and demonstrate how the use of partially-reduced-form models can help to overcome some of the parameter estimation and evaluation problems associated with models containing composites. Diagnostic procedures for evaluating the most appropriate and effective use of composites are illustrated with an example from the ecological literature. It is argued that an ability to incorporate composite variables into structural equation models may be particularly valuable in the study of natural systems, where concepts are frequently multifaceted and the influence of suites of variables are often of interest. ?? Springer Science+Business Media, LLC 2007.

  2. Labour input in construction of composite structures of the Balakovo NPP reactor compartment

    International Nuclear Information System (INIS)

    Alasyuk, G.Ya.

    1988-01-01

    Technical-economical results achieved when constructing the Balakovo NPP second unit reactor compartment structures are presented. The obtained data analysis shows that in the case of building the walls of non-sealed reactor compartment section in the form of composite structures the major part of labour input requirements (54-59%) falls at works on production and mounting of these structures, performed at auxiliary plants. Labour input for works performed the construction (unit-cell and space frame mounting, preparation of units for concreting, joint sealing, concrete placement) make up 41-46%, and labour input for enlarged unit-cell mounting make up 8%. Labour input per 1 m 3 of the wall structure with 0.6 and 0.9 m thicness in the monolith option are respectively by 19 an 23% higher than the same indices for composite

  3. Resin transfer molding for advanced composite primary aircraft structures

    Science.gov (United States)

    Markus, Alan; Palmer, Ray

    1991-01-01

    Resin Transfer Molding (RTM) has been identified by Douglas Aircraft Company (DAC) and industry to be one of the promising processes being developed today which can break the cost barrier of implementing composite primary structures into a commercial aircraft production environment. The RTM process developments and scale-up plans Douglas Aircrart will be conducting under the NASA ACT contract are discussed.

  4. Composition dependence of the optical and structural properties of Eu-doped oxyfluoride glasses

    DEFF Research Database (Denmark)

    Zhu, C.F.; Wu, D.Q.; Zhang, Y.F.

    2015-01-01

    Europium doped oxyfluoride glasses were prepared by the melt quenching method for the light emitting diodes applications. The optical and structural properties of these glasses were studied by means of photoluminescence spectra, Commission Internationale de L'Eclairage chromaticity coordinates, X...... compositions. Finally, we propose a mechanism to explain how the glass structure affects the reduction of Eu ions as well as optical properties of the glasses.......Europium doped oxyfluoride glasses were prepared by the melt quenching method for the light emitting diodes applications. The optical and structural properties of these glasses were studied by means of photoluminescence spectra, Commission Internationale de L'Eclairage chromaticity coordinates, X...... on the base glass compositions. For certain base glass compositions, CaF2 crystals can form during the melt cooling process, and thereby enhance the conversion from Eu3+ to Eu2+. The formation of CaF2 crystals can be suppressed by adding CaO, Al2O3 and B2O3, but enhanced by adding Na2O and K2O in glass...

  5. Structure and properties of nanocrystalline soft magnetic composite materials with silicon polymer matrix

    International Nuclear Information System (INIS)

    Dobrzanski, L.A.; Nowosielski, R.; Konieczny, J.; PrzybyI, A.; WysIocki, J.

    2005-01-01

    The paper concerns investigation of nanocrystalline composites technology preparation. The composites in the form of rings with rectangular transverse section, and with polymer matrix and nanocrystalline metallic powders fulfillment were made, for obtaining good ferromagnetic properties. The nanocrystalline ferromagnetic powders were manufactured by high-energy ball milling of metallic glasses strips in an as-quenched state. Generally for investigation, Co matrix alloys with the silicon polymer were used. Magnetic properties in the form of hysteresis loop by rings method were measured. Generally composite cores showed lower soft ferromagnetic properties than winded cores of nanocrystalline strips, but composite cores showed interesting mechanical properties. Furthermore, the structure of strips and powders on properties of composites were investigated

  6. Composite foods: from structure to sensory perception.

    Science.gov (United States)

    Scholten, Elke

    2017-02-22

    An understanding of the effect of structural features of foods in terms of specific sensory attributes is necessary to design foods with specific functionalities, such as reduced fat or increased protein content, and increased feeling of satiety or liking. Although the bulk rheological properties of both liquid and solid foods can be related to textural attributes such as thickness and firmness, they do not always correlate to more complex sensory attributes, such as creamy and smooth. These attributes are often a result of different contributions, including lubrication aspects and interactions between food and components present in the oral cavity. In this review, the different contributions for a variety of composite foods, such as dispersions, emulsions and emulsion-filled gels, are discussed. The rheological properties are discussed in relation to specific structural characteristics of the foods, which are then linked to lubrication aspects and sensory perception.

  7. A study on the crushing behavior of basalt fiber reinforced composite structures

    Science.gov (United States)

    Pandian, A.; Veerasimman, A. P.; Vairavan, M.; Francisco, C.; Sultan, M. T. H.

    2016-10-01

    The crushing behavior and energy absorption capacity of basalt fiber reinforced hollow square structure composites are studied under axial compression. Using the hand layup technique, basalt fiber reinforced composites were fabricated using general purpose (GP) polyester resin with the help of wooden square shaped mould of varying height (100 mm, 150 mm and 200 mm). For comparison, similar specimens of glass fiber reinforced polymer composites were also fabricated and tested. Axial compression load is applied over the top end of the specimen with cross head speed as 2 mm/min using Universal Testing Machine (UTM). From the experimental results, the load-deformation characteristics of both glass fiber and basalt fiber composites were investigated. Crashworthiness and mode of collapse for the composites were determined from load-deformation curve, and they were then compared to each other in terms of their crushing behaviors.

  8. 77 FR 71211 - Request for Information: Establish a Public-Private Collaboration, “Drug Development Initiative...

    Science.gov (United States)

    2012-11-29

    ... Agreement (CRADA) under the authority of the Federal Technology Transfer Act of 1986 (FTTA), Public Law 99-502, codified as amended in scattered sections of title 15, United States Code (U.S.C.). The CRADA... DDI focused on new pharmacological treatments for PTSD. Collaborations will be delineated via a CRADA...

  9. Studies on the structure and properties of thermoplastic starch/luffa fiber composites

    International Nuclear Information System (INIS)

    Kaewtatip, Kaewta; Thongmee, Jariya

    2012-01-01

    Highlights: ► Thermoplastic starch/luffa fiber composites were prepared using compression molding. ► The tensile strengths of the composites were higher than for thermoplastic starch. ► Degradation temperatures of the composites were higher than for thermoplastic starch. ► Luffa fiber decreases the water absorption of TPS. -- Abstract: Thermoplastic starch (TPS)/luffa fiber composites were prepared using compression molding. The luffa fiber contents ranged from 0 wt.% to 20 wt.%. The tensile strength of the TPS/luffa fiber composite with 10 wt.% of luffa fiber had a twofold increase compared to TPS. The temperature values of maximum weight loss of the TPS/luffa fiber composites were higher than for TPS. The water absorption of the TPS/luffa fiber composites decreased significantly when the luffa fiber contents increased. The strength of adhesion between the luffa fiber and the TPS matrix was clearly demonstrated by their compatibility presumably due to their similar chemical structures as shown by scanning electron microscope (SEM) micrographs and Fourier transform infrared (FTIR) spectra.

  10. Optimal Design of Composite Structures Under Manufacturing Constraints

    DEFF Research Database (Denmark)

    Marmaras, Konstantinos

    algorithms to perform the global optimization. The efficiency of the proposed models is examined on a set of well–defined discrete multi material and thickness optimization problems originating from the literature. The inclusion of manufacturing limitations along with structural considerations in the early...... mixed integer 0–1 programming problems. The manufacturing constraints have been treated by developing explicit models with favorable properties. In this thesis we have developed and implemented special purpose global optimization methods and heuristic techniques for solving this class of problems......This thesis considers discrete multi material and thickness optimization of laminated composite structures including local failure criteria and manufacturing constraints. Our models closely follow an immediate extension of the Discrete Material Optimization scheme, which allows simultaneous...

  11. Remnant trees affect species composition but not structure of tropical second-growth forest.

    Science.gov (United States)

    Sandor, Manette E; Chazdon, Robin L

    2014-01-01

    Remnant trees, spared from cutting when tropical forests are cleared for agriculture or grazing, act as nuclei of forest regeneration following field abandonment. Previous studies on remnant trees were primarily conducted in active pasture or old fields abandoned in the previous 2-3 years, and focused on structure and species richness of regenerating forest, but not species composition. Our study is among the first to investigate the effects of remnant trees on neighborhood forest structure, biodiversity, and species composition 20 years post-abandonment. We compared the woody vegetation around individual remnant trees to nearby plots without remnant trees in the same second-growth forests ("control plots"). Forest structure beneath remnant trees did not differ significantly from control plots. Species richness and species diversity were significantly higher around remnant trees. The species composition around remnant trees differed significantly from control plots and more closely resembled the species composition of nearby old-growth forest. The proportion of old-growth specialists and generalists around remnant trees was significantly greater than in control plots. Although previous studies show that remnant trees may initially accelerate secondary forest growth, we found no evidence that they locally affect stem density, basal area, and seedling density at later stages of regrowth. Remnant trees do, however, have a clear effect on the species diversity, composition, and ecological groups of the surrounding woody vegetation, even after 20 years of forest regeneration. To accelerate the return of diversity and old-growth forest species into regrowing forest on abandoned land, landowners should be encouraged to retain remnant trees in agricultural or pastoral fields.

  12. Compositional and structural characterisation of GaSb and GaInSb

    International Nuclear Information System (INIS)

    Corregidor, V.; Alves, E.; Alves, L.C.; Barradas, N.P.; Duffar, Th.; Franco, N.; Marques, C.; Mitric, A.

    2005-01-01

    Low band gap III-V semiconductors are researched for applications in thermophotovoltaic technology. GaSb crystal is often used as a substrate. Ga 1-x In x Sb is also a promising substrate material, because its lattice parameters can be adjusted by controlling x. We used a new method to synthesise GaSb and GaInSb, in which a high frequency alternate magnetic field is used to heat, to melt and to mix the elements. We present a compositional and structural characterisation of the materials using a combination of complementary techniques. Rutherford backscattering was used to determine accurately the composition of the GaSb. With proton induced X-ray emission in conjunction with a 3 x 3 μm 2 micro-beam we studied the homogeneity of the samples. Structural analysis and phase identification were done with X-ray diffraction. The results for GaSb show a homogeneous composition while the GaInSb samples were found to be strongly heterogeneous at the end of the ingot. The ingots produced are competitive feed material, when compared to other growth techniques, to be used in a second step for the production of good quality ternary crystals

  13. Theoretical Calculation and Analysis on the Composite Rock-Bolt Bearing Structure in Burst-Prone Ground

    Directory of Open Access Journals (Sweden)

    Liang Cheng

    2015-01-01

    Full Text Available Given the increase in mining depth and intensity, tunnel failure as a result of rock burst has become an important issue in the field of mining engineering in China. Based on the Composite Rock-Bolt Bearing Structure, which is formed due to the interaction of the bolts driven into the surrounding rock, this paper analyzes a rock burst prevention mechanism, establishes a mechanical model in burst-prone ground, deduces the strength calculation formula of the Composite Rock-Bolt Bearing Structure in burst-prone ground, and confirms the rock burst prevention criterion of the Composite Rock-Bolt Bearing Structure. According to the rock burst prevention criterion, the amount of the influence on rock burst prevention ability from the surrounding rock parameters and bolt support parameters is discussed.

  14. Thermo-structural analysis and electrical conductivity behavior of epoxy/metals composites

    Science.gov (United States)

    Boumedienne, N.; Faska, Y.; Maaroufi, A.; Pinto, G.; Vicente, L.; Benavente, R.

    2017-05-01

    This paper reports on the elaboration and characterization of epoxy resin filled with metallic particles powder (aluminum, tin and zinc) composites. The scanning electron microscopy (SEM) pictures, density measurements and x-ray diffraction analysis (DRX) showed a homogeneous phase of obtained composites. The differential scanning calorimetry revealed a good adherence at matrix-filler interfaces, confirming the SEM observations. The measured glass transition temperatures depend on composites fillers' nature. Afterwards, the electrical conductivity of composites versus their fillers' contents has been investigated. The obtained results depict a nonlinear behavior, indicating an insulator to conductor phase transition at a conduction threshold; with high contrast of ten decades. Hence, the elaborated materials give a possibility to obtain dielectric or electrically conducting phases, which can to be interesting in the choice of desired applications. Finally, the obtained results have been successfully simulated on the basis of different percolation models approach combined with structural characterization inferences.

  15. Graphene/polyaniline composite sponge of three-dimensional porous network structure as supercapacitor electrode

    International Nuclear Information System (INIS)

    Jiang Jiu-Xing; Zhang Xu-Zhi; Wang Zhen-Hua; Xu Jian-Jun

    2016-01-01

    As a supercapacitor electrode, the graphene/polyaniline (PANI) composite sponge with a three-dimensional (3D) porous network structure is synthesized by a simple three-step method. The three steps include an in situ polymerization, freeze-drying and reduction by hydrazine vapor. The prepared sponge has a large specific surface area and porous network structure, so it is in favor of spreading the electrolyte ion and increasing the charge transfer efficiency of the system. The process of preparation is simple, easy to operate and low cost. The composite sponge shows better electrochemical performance than the pure individual graphene sponge while PANI cannot keep the shape of a sponge. Such a composite sponge exhibits specific capacitances of 487 F·g −1 at 2 mV/s compared to pristine PANI of 397 F·g −1 . (paper)

  16. Structural and thermal properties of silk fibroin - Silver nanoparticles composite films

    Science.gov (United States)

    Shivananda, C. S.; Rao B, B. Lakshmeesha; Shetty, G. Rajesh; Sangappa, Y.

    2018-05-01

    In this work, silk fibroin-silver nanoparticles (SF-AgNPs) composite films have been prepared by simple solution casting method. The composite films were examined for structural and thermal properties using X-ray diffraction (XRD), thermogravimatric (TGA) and differential scanning calorimetry (DSC) analysis. The XRD results showed that with the introduction of AgNPs in the silk fibroin matrix the amorphous nature of the silk fibroin decreases with increasing nanoparticles concentration. The silk fibroin films possess good thermal stability with the presence of AgNPs.

  17. COMPUTER MODELING OF STRUCTURAL - CONCENTRATION CHARACTERISTICS OF BUILDING COMPOSITE MATERIALS

    Directory of Open Access Journals (Sweden)

    I. I. Zaripova

    2015-09-01

    Full Text Available In the article the computer modeling of structural and concentration characteristics of the building composite material on the basis of the theory of the package. The main provisions of the algorithmon the basis of which it was possible to get the package with a significant number of packaged elements, making it more representative in comparison with existing analogues modeling. We describe the modeled area related areas, the presence of which determines the possibility of a percolation process, which in turn makes it possible to study and management of individual properties of the composite material of construction. As an example of the construction of a composite material is considered concrete that does not exclude the possibility of using algorithms and modeling results of similar studies for composite matrix type (matrix of the same material and distributed in a certain way by volume particles of another substance. Based on modeling results can be manufactured parts and construction elementsfor various purposes with improved technical characteristics (by controlling the concentration composition substance.

  18. Evaluation of the filler packing structures in dental resin composites: From theory to practice.

    Science.gov (United States)

    Wang, Ruili; Habib, Eric; Zhu, X X

    2018-07-01

    The aim of this study is to evaluate the packing properties of uniform silica particles and their mixture with secondary particles yielding maximally loaded dental composites. We intend to verify the difference between the idealized models (the close-packed structures and the random-packed structures) and the actual experimental results, in order to provide guidance for the preparation of dental composites. The influence of secondary particle size and the resin composition on the physical-mechanical properties and the rheological properties of the experimental dental composites was also investigated. Silica particles (S-920, S-360, and S-195) with average diameters of 920, 360, and 195nm were synthesized via the Stöber process. Their morphology and size distribution were determined by field-emission scanning electron microscopy and laser particle sizer. A series of silica fillers, S-920, S-920+195, S-920+360, and S-920+360+195, were then formulated with two Bis-GMA/TEGDMA resins (weight ratios of 70:30 and 50:50). For these experimental dental composites, their maximum filler loadings were assessed and compared to the theory. The mechanical properties, degree of conversion, depth of cure, and polymerization shrinkage of these composites were then evaluated. Their rheological behaviors were measured with a rheometer. Unimodal S-920 had the maximally filler loading of 70.80wt% with the 5B5T resin, close to the theoretical estimation of the random loose packing (71.92wt%). The maximum loading of the S-920+360+195 filled composite was 72.92wt% for the same resin, compared to the theoretical estimation of 89.29wt% obtained for the close-packed structures. These findings indicate that random loose packing matches more closely to the real packing state for the filler formulations used. When maximally loaded, the composite with S-920+360+195 produced the best mechanical properties and the lowest polymerization shrinkage. The degree of conversion and depth of cure were

  19. COMPOSITIONAL AND SUBSTANTIAL STRUCTURE OF THE MEDICAL DOCUMENT: FORMATION STAGES

    Directory of Open Access Journals (Sweden)

    Romashova Olga Vladimirovna

    2015-03-01

    Full Text Available The article deals with the compositional and substantial structure of the ambulatory medical record, or "case history", which has being formed for a long time. The author allocates the three main periods in the formation of this medical document: the first period (the beginning of the 19th century – 1920s is connected with the origin and formation; the second period (1920-1980s is marked by emergence of the normative legal acts regulating registration and maintaining; the third period (1980s – up to the present is associated with the cancellation of regulations and the introduction of the new order of the Ministry of Health of the USSR that changed the document's form and name. It is determined that the composition of the case history consists of the title page and the main part. The following processes take place in the course of ambulatory medical record's formation: strengthening formalization, increase in the number of pattern text fragments, increase in the text's volume, and the implementation of bigger number of functions. The author reveals the main (informative and cumulative, accounting and additional (scientific, controlling, legal, financial functions of the document. The implementation of these functions is reflected in the compositional and substantial structure of the document text and is conditioned by a number of extralinguistic factors.

  20. Ply-based Optimization of Laminated Composite Shell Structures under Manufacturing Constraints

    DEFF Research Database (Denmark)

    Sørensen, Rene; Lund, Erik

    2012-01-01

    This work concerns a new ply-based parameterization for performing simultaneous material selection and topology optimization of fiber reinforced laminated composite structures while ensuring that a series of different manufacturing constraints are fulfilled. The material selection can either...

  1. Analysis of a ceramic filled bio-plastic composite sandwich structure

    International Nuclear Information System (INIS)

    Habib Ullah, M.; Islam, M. T.

    2013-01-01

    Design and analysis of a ceramic-filled bio-plastic composite sandwich structure is presented. This proposed high-dielectric structure is used as a substrate for patch antennas. A meandered-strip line-fed fractal-shape patch antenna is designed and fabricated on a copper-laminated sandwich-structured substrate. Measurement results of this antenna show 44% and 20% of bandwidths with maximum gains of 3.45 dBi and 5.87 dBi for the lower and upper bands, respectively. The half-power beam widths of 104° and 78° have been observed from the measured radiation pattern at the two resonance frequencies 0.9 GHz and 2.5 GHz

  2. Analysis of a ceramic filled bio-plastic composite sandwich structure

    Energy Technology Data Exchange (ETDEWEB)

    Habib Ullah, M. [Institute of Space Science (ANGKASA), Universiti Kebangsaan Malaysia, Bangi Selangor 43600 (Malaysia); Department of Electrical, Electronic and System Engineering, Universiti Kebangsaan Malaysia, Bangi 43600 (Malaysia); Islam, M. T. [Institute of Space Science (ANGKASA), Universiti Kebangsaan Malaysia, Bangi Selangor 43600 (Malaysia)

    2013-11-25

    Design and analysis of a ceramic-filled bio-plastic composite sandwich structure is presented. This proposed high-dielectric structure is used as a substrate for patch antennas. A meandered-strip line-fed fractal-shape patch antenna is designed and fabricated on a copper-laminated sandwich-structured substrate. Measurement results of this antenna show 44% and 20% of bandwidths with maximum gains of 3.45 dBi and 5.87 dBi for the lower and upper bands, respectively. The half-power beam widths of 104° and 78° have been observed from the measured radiation pattern at the two resonance frequencies 0.9 GHz and 2.5 GHz.

  3. Computational Analysis of Effect of Transient Fluid Force on Composite Structures

    Science.gov (United States)

    2013-12-01

    as they well represent an E-glass fiber reinforced composite frequently used in research and industrial applications. The fluid domain was sized...provide unique perspectives on peak stress ratios . The two models both share increased structural rigidity. The cylinder is reinforced by... Poisson ratio of 0.3 and Young’s modulus of 20 GPa were added to the transient structural engineering data cell (Figure 69). 78 Figure 69. E-Glass

  4. Modeling and Design Analysis Methodology for Tailoring of Aircraft Structures with Composites

    Science.gov (United States)

    Rehfield, Lawrence W.

    2004-01-01

    Composite materials provide design flexibility in that fiber placement and orientation can be specified and a variety of material forms and manufacturing processes are available. It is possible, therefore, to 'tailor' the structure to a high degree in order to meet specific design requirements in an optimum manner. Common industrial practices, however, have limited the choices designers make. One of the reasons for this is that there is a dearth of conceptual/preliminary design analysis tools specifically devoted to identifying structural concepts for composite airframe structures. Large scale finite element simulations are not suitable for such purposes. The present project has been devoted to creating modeling and design analysis methodology for use in the tailoring process of aircraft structures. Emphasis has been given to creating bend-twist elastic coupling in high aspect ratio wings or other lifting surfaces. The direction of our work was in concert with the overall NASA effort Twenty- First Century Aircraft Technology (TCAT). A multi-disciplinary team was assembled by Dr. Damodar Ambur to work on wing technology, which included our project.

  5. Synthesis on the durability of composite fiberglass/epoxy resin structures; Synthese sur la durabilite des structures composites en fibres de verre/resine epoxide

    Energy Technology Data Exchange (ETDEWEB)

    Thevenin, P. [Electricite de France (EDF), Direction des Etudes et Recherches, 92 - Clamart (France)

    1997-12-31

    The purpose of this paper is to collect together in a systematic way information and results relating to the durability of composite fiberglass/ epoxy resin structures. First it is a matter of assessing the average level of understanding the long term behaviour of these structures which change under the combined effects of varied mechanical loading and stresses of a physico-chemical type linked to the environment. Looking at phenomena encountered and facts from current analyses, it will then be advisable to specify a methodology which can be applied to industrial piping used in PWR cooling systems for transporting raw water under pressure. In fact assessment of their service life is at present based on long and costly testing (ASTM D 2992 B standard), the appearance of which is inherited from metal piping testing.. Therefore it appears essential to study substitution test procedures, more composite specific and at the same time which can be conducted in reasonable time. For this purpose, by coherently accelerating and combining them in order not to underestimate their effects, ageing tests shall reproduce mechanisms representative of operating conditions. (author). 113 refs.

  6. Synthesis on the durability of composite fiberglass/epoxy resin structures; Synthese sur la durabilite des structures composites en fibres de verre/resine epoxide

    Energy Technology Data Exchange (ETDEWEB)

    Thevenin, P [Electricite de France (EDF), Direction des Etudes et Recherches, 92 - Clamart (France)

    1998-12-31

    The purpose of this paper is to collect together in a systematic way information and results relating to the durability of composite fiberglass/ epoxy resin structures. First it is a matter of assessing the average level of understanding the long term behaviour of these structures which change under the combined effects of varied mechanical loading and stresses of a physico-chemical type linked to the environment. Looking at phenomena encountered and facts from current analyses, it will then be advisable to specify a methodology which can be applied to industrial piping used in PWR cooling systems for transporting raw water under pressure. In fact assessment of their service life is at present based on long and costly testing (ASTM D 2992 B standard), the appearance of which is inherited from metal piping testing.. Therefore it appears essential to study substitution test procedures, more composite specific and at the same time which can be conducted in reasonable time. For this purpose, by coherently accelerating and combining them in order not to underestimate their effects, ageing tests shall reproduce mechanisms representative of operating conditions. (author). 113 refs.

  7. Ceramic Composite Mechanical Fastener System for High-Temperature Structural Assemblies, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Hot structures fabricated from ceramic composite materials are an attractive design option for components of future high-speed aircraft, re-entry vehicles and...

  8. Study of damping characteristics of fibre reinforced composite aerospace structure

    International Nuclear Information System (INIS)

    Khan, M.Z.; Saleh, S.; Munir, A.

    2006-01-01

    Composite materials are used in a variety of high demanding structural applications. Apart from their other preferable properties, they have high-energy dissipation characteristics, which is important aspect when we repeatedly wiggle the system back and forth. It is important to have thorough understanding of material damping behavior; in general materials damping tends to be complex nonlinear function of vibration amplitude, frequency of loading and material formulation. There are number of mathematical models available in literature to obtain hysteresis curves. One approach for identifying damping characteristics used mechanical hysteresis curves. In present work, a phenomenon was observed during testing of fibre reinforced composite beam of an aerospace structure, that for increase load in structure, the path of Force vs. Displacement curve is different than the path of unloading. A plot is generated which indicate the hysteresis loop representing the steady state dynamic behavior of material. The area enclosed by such curves is proportional to energy dissipation per cycle. However, the specific shape of the curve also has important implications for characterizing the specific functional form of the damping. Therefore, it is important to develop methods for accurately accounting for such effects. The current work explores the damping characteristics both theoretically and experimentally. (author)

  9. Selective logging: does the imprint remain on tree structure and composition after 45 years?

    Science.gov (United States)

    Osazuwa-Peters, Oyomoare L.; Chapman, Colin A.; Zanne, Amy E.

    2015-01-01

    Selective logging of tropical forests is increasing in extent and intensity. The duration over which impacts of selective logging persist, however, remains an unresolved question, particularly for African forests. Here, we investigate the extent to which a past selective logging event continues to leave its imprint on different components of an East African forest 45 years later. We inventoried 2358 stems ≥10 cm in diameter in 26 plots (200 m × 10 m) within a 5.2 ha area in Kibale National Park, Uganda, in logged and unlogged forest. In these surveys, we characterized the forest light environment, taxonomic composition, functional trait composition using three traits (wood density, maximum height and maximum diameter) and forest structure based on three measures (stem density, total basal area and total above-ground biomass). In comparison to unlogged forests, selectively logged forest plots in Kibale National Park on average had higher light levels, different structure characterized by lower stem density, lower total basal area and lower above-ground biomass, and a distinct taxonomic composition driven primarily by changes in the relative abundance of species. Conversely, selectively logged forest plots were like unlogged plots in functional composition, having similar community-weighted mean values for wood density, maximum height and maximum diameter. This similarity in functional composition irrespective of logging history may be due to functional recovery of logged forest or background changes in functional attributes of unlogged forest. Despite the passage of 45 years, the legacy of selective logging on the tree community in Kibale National Park is still evident, as indicated by distinct taxonomic and structural composition and reduced carbon storage in logged forest compared with unlogged forest. The effects of selective logging are exerted via influences on tree demography rather than functional trait composition. PMID:27293697

  10. Durability of polymer matrix composites for automotive structural applications: A state-of-the-art review

    Energy Technology Data Exchange (ETDEWEB)

    Corum, J.M.; Simpson, W.A. Jr.; Sun, C.T.; Talreja, R.; Weitsman, Y.J.

    1995-07-01

    A key unanswered question that must be addressed before polymeric composites will be widely used in automotive structural components is their known durability. Major durability issues are the effects that cyclic loadings, creep, automotive fluid environments, and low-energy impacts have on dimensional stability, strength, and stiffness throughout the required life of a composite component. This report reviews the current state of understanding in each of these areas. It also discusses the limited information that exists on one of the prime candidate materials for automotive structural applications--an isocyanurate reinforced with a continuous strand, swirl mat. Because of the key role that nondestructive evaluations must play in understanding damage development and progression, a chapter is included on ultrasonic techniques. A final chapter then gives conclusions and recommendations for research needed to resolve the various durability issues. These recommendations will help provide a sound basis for program planning for the Durability of Lightweight Composite Structures Project sponsored by the US Department of Energy in cooperation with the Automotive Composites Consortium of Chrysler, Ford, and General Motors.

  11. Structure, composition and function of interfaces in ceramic fibre/matrix composites

    International Nuclear Information System (INIS)

    Pippel, E.

    1993-01-01

    Improving the properties of fibre reinforced ceramics and glasses by optimizing their microstructure requires the knowledge of this structure down to the atomic level. In these materials energy-dissipative processes during fracture particularly act within an interface layer or layer system between fibre and matrix which can either be produced by fibre coating, or which develops during the processing of the composites. Examples are presented of the microstructural phenomena of such layers revealed by HVEM and HREM and complemented by microchemical information via a nanoscale EDXS equipment. The investigations are carried out on Nicalon fibres in Duran glass as well as on Tyranno, Nicalon and carbon fibres in different SiC-matrices. Finally, a process is discussed which may control the important interface parameters. (orig.)

  12. Development of the SSTL-300-S1 Composite Imager Barrel Structure

    Science.gov (United States)

    Hamar, Chris; Wood, Trevor; Alsami, Sami; Hallett, Ben

    2014-06-01

    The SSTL-300-S1 is the latest in the family of highly capable SSTL-300 platforms, providing high resolution imagery with all the existing mission performance of the heritage platform. In developing the product, SSTL has had to undertake the development of a composite imager barrel assembly, which forms the payload instrument's primary structure. Working to a nominal schedule of 24 months from requirements definition to structural qualification, the barrel's development philosophy has had to carefully balance the interdependent optical, structural and programmatic requirements. This paper provides a brief summary description of that development.

  13. The Candida albicans Biofilm Matrix: Composition, Structure and Function.

    Science.gov (United States)

    Pierce, Christopher G; Vila, Taissa; Romo, Jesus A; Montelongo-Jauregui, Daniel; Wall, Gina; Ramasubramanian, Anand; Lopez-Ribot, Jose L

    2017-03-01

    A majority of infections caused by Candida albicans -the most frequent fungal pathogen-are associated with biofilm formation. A salient feature of C. albicans biofilms is the presence of the biofilm matrix. This matrix is composed of exopolymeric materials secreted by sessile cells within the biofilm, in which all classes of macromolecules are represented, and provides protection against environmental challenges. In this review, we summarize the knowledge accumulated during the last two decades on the composition, structure, and function of the C. albicans biofilm matrix. Knowledge of the matrix components, its structure, and function will help pave the way to novel strategies to combat C. albicans biofilm infections.

  14. Design Optimization of Laminated Composite Structures with Many Local Strength Criteria

    DEFF Research Database (Denmark)

    Lund, Erik

    2012-01-01

    This paper presents different strategies for handling very many local strength criteria in structural optimization of laminated composites. Global strength measures using Kreisselmeier-Steinhauser or p-norm functions are introduced for patch-wise parameterizations, and the efficiency of the metho...

  15. Toughened and corrosion- and wear-resistant composite structures and fabrication methods thereof

    Science.gov (United States)

    Seals, Roland D.; Ripley, Edward B.; Hallman, Russell L.

    2017-06-20

    Composite structures having a reinforced material interjoined with a substrate, wherein the reinforced material comprises a compound selected from the group consisting of titanium monoboride, titanium diboride, and combinations thereof.

  16. Research on the nanolevel influence of surfactants on structure formation of the hydrated Portland cement compositions

    Directory of Open Access Journals (Sweden)

    Guryanov Alexander

    2016-01-01

    Full Text Available The research of the structure formation process on a nanolevel of the samples of hydrated Portland cement compositions containing the modifying additives has been conducted with the help of small angle neutron scattering method. Carbonate and aluminum alkaline slimes as well as the complex additives containing surfactants were used as additives. The influence of slimes and surfactants on structural parameters change of Portland cement compositions of the average size of the disseminating objects, fractal dimension samples is considered. These Portland cement compositions are shown to be fractal clusters.

  17. Analysis of thin composite structures using an efficient hex-shell finite element

    Energy Technology Data Exchange (ETDEWEB)

    Shiri, Seddik [Universite Bordeaux, Pessac (France); Naceur, Hakim [Universite de valenciennes, Valenciennes (France)

    2013-12-15

    In this paper a general methodology for the modeling of material composite multilayered shell structures is proposed using a Hex-shell finite element modeling. The first part of the paper is devoted to the general FE formulation of the present composite 8-node Hex-shell element called SCH8, based only on displacement degrees of freedom. A particular attention is given to alleviate shear, trapezoidal and thickness locking, without resorting to the classical plane-stress assumption. The anisotropic material behavior of layered shells is modeled using a fully three dimensional elastic orthotropic material law in each layer, including the thickness stress component. Applications to laminate thick shell structures are studied to validate the methodology, and good results have been obtained in comparison with ABAQUS commercial code.

  18. Critical Joints in Large Composite Primary Aircraft Structures. Volume 3: Ancillary Test Results

    Science.gov (United States)

    Bunin, Bruce L.; Sagui, R. L.

    1985-01-01

    A program was conducted to develop the technology for critical structural joints for composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. The results of a comprehensive ancillary test program are summarized, consisting of single-bolt composite joint specimens tested in a variety of configurations. These tests were conducted to characterize the strength and load deflection properties that are required for multirow joint analysis. The composite material was Toray 300 fiber and Ciba-Geigy 914 resin, in the form of 0.005 and 0.01 inch thick unidirectional tape. Tests were conducted in single and double shear for loaded and unloaded hole configurations under both tensile and compressive loading. Two different layup patterns were examined. All tests were conducted at room temperature. In addition, the results of NASA Standard Toughness Test (NASA RP 1092) are reported, which were conducted for several material systems.

  19. Diamagnetic composite material structure for reducing undesired electromagnetic interference and eddy currents in dielectric wall accelerators and other devices

    Science.gov (United States)

    Caporaso, George J.; Poole, Brian R.; Hawkins, Steven A.

    2015-06-30

    The devices, systems and techniques disclosed here can be used to reduce undesired effects by magnetic field induced eddy currents based on a diamagnetic composite material structure including diamagnetic composite sheets that are separated from one another to provide a high impedance composite material structure. In some implementations, each diamagnetic composite sheet includes patterned conductor layers are separated by a dielectric material and each patterned conductor layer includes voids and conductor areas. The voids in the patterned conductor layers of each diamagnetic composite sheet are arranged to be displaced in position from one patterned conductor layer to an adjacent patterned conductor layer while conductor areas of the patterned conductor layers collectively form a contiguous conductor structure in each diamagnetic composite sheet to prevent penetration by a magnetic field.

  20. Light Modulation and Water Splitting Enhancement Using a Composite Porous GaN Structure.

    Science.gov (United States)

    Yang, Chao; Xi, Xin; Yu, Zhiguo; Cao, Haicheng; Li, Jing; Lin, Shan; Ma, Zhanhong; Zhao, Lixia

    2018-02-14

    On the basis of the laterally porous GaN, we designed and fabricated a composite porous GaN structure with both well-ordered lateral and vertical holes. Compared to the plane GaN, the composite porous GaN structure with the combination of the vertical holes can help to reduce UV reflectance and increase the saturation photocurrent during water splitting by a factor of ∼4.5. Furthermore, we investigated the underlying mechanism for the enhancement of the water splitting performance using a finite-difference time-domain method. The results show that the well-ordered vertical holes can not only help to open the embedded pore channels to the electrolyte at both sides and reduce the migration distance of the gas bubbles during the water splitting reactions but also help to modulate the light field. Using this composite porous GaN structure, most of the incident light can be modulated and trapped into the nanoholes, and thus the electric fields localized in the lateral pores can increase dramatically as a result of the strong optical coupling. Our findings pave a new way to develop GaN photoelectrodes for highly efficient solar water splitting.

  1. Multi-material Preforming of Structural Composites

    Energy Technology Data Exchange (ETDEWEB)

    Norris, Robert E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Eberle, Cliff C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pastore, Christopher M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sudbury, Thomas Z. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Xiong, Fue [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hartman, David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-05-01

    Fiber-reinforced composites offer significant weight reduction potential, with glass fiber composites already widely adopted. Carbon fiber composites deliver the greatest performance benefits, but their high cost has inhibited widespread adoption. This project demonstrates that hybrid carbon-glass solutions can realize most of the benefits of carbon fiber composites at much lower cost. ORNL and Owens Corning Reinforcements along with program participants at the ORISE collaborated to demonstrate methods for produce hybrid composites along with techniques to predict performance and economic tradeoffs. These predictions were then verified in testing coupons and more complex demonstration articles.

  2. Influence of residual composition on the structure and properties of extracellular matrix derived hydrogels.

    Science.gov (United States)

    Claudio-Rizo, Jesús A; Rangel-Argote, Magdalena; Castellano, Laura E; Delgado, Jorge; Mata-Mata, José L; Mendoza-Novelo, Birzabith

    2017-10-01

    In this work, hydrolysates of extracellular matrix (hECM) were obtained from rat tail tendon (TR), bovine Achilles tendon (TAB), porcine small intestinal submucosa (SIS) and bovine pericardium (PB), and they were polymerized to generate ECM hydrogels. The composition of hECM was evaluated by quantifying the content of sulphated glycosaminoglycans (sGAG), fibronectin and laminin. The polymerization process, structure, physicochemical properties, in vitro degradation and biocompatibility were studied and related to their composition. The results indicated that the hECM derived from SIS and PB were significantly richer in sGAG, fibronectin and laminin, than those derived from TAB and TR. These differences in hECM composition influenced the polymerization and the structural characteristics of the fibrillar gel network. Consequently, the swelling, mechanics and degradation of the hydrogels showed a direct relationship with the remaining composition. Moreover, the cytocompatibility and the secretion of transforming growth factor beta-1 (TGF-β1) by macrophages were enhanced in hydrogels with the highest residual content of ECM biomolecules. The results of this work evidenced the role of the ECM molecules remaining after both decellularization and hydrolysis steps to produce tissue derived hydrogels with structure and properties tailored to enhance their performance in tissue engineering and regenerative medicine applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Experimental study on beam for composite CES structural system

    Science.gov (United States)

    Matsui, Tomoya

    2017-10-01

    Development study on Concrete Encase Steel (CES) composite structure system has been continuously conducted toward the practical use. CES structure is composed of steel and fiber reinforced concrete. In previous study, it was found that CES structure has good seismic performance from experimental study of columns, beam - column joints, shear walls and a two story two span frame. However, as fundamental study on CES beam could be lacking, it is necessary to understand the structural performance of CES beam. In this study, static loading tests of CES beams were conducted with experimental valuable of steel size, the presence or absence of slab and thickness of slab. And restoring characteristics, failure behavior, deformation behavior, and strength evaluation method of CES beam were investigated. As the results, it was found that CES beam showed stable hysteresis behavior. Furthermore it was found that the flexural strength of the CES beam could be evaluated by superposition strength theory.

  4. The influence of compositional and structural diversity on forest productivity

    Science.gov (United States)

    James N. Long; John D. Shaw

    2010-01-01

    Data from ~1500 ponderosa pine (Pinus ponderosa C. Lawson) stands in the western United States were used to examine the potential influence of compositional and structural diversity on forest productivity. Relative density, height and site quality were combined in a conceptually sound expression of the relationship between growth and growing stock for ponderosa pine-...

  5. Plant species composition and structure of the Mana Angetu moist ...

    African Journals Online (AJOL)

    A floristic composition and structure study of the Mana Angetu Forest was carried out between July 2003 and June 2004 at four sites of the forest with an altitudinal range of 1533-2431 m. Three transects, 750 ... Analysis of Importance Value Index indicated that Vepris dainellii had the highest value (79). The population ...

  6. Damage Evaluation and Analysis of Composite Pressure Vessels Using Fiber Bragg Gratings to Determine Structural Health

    National Research Council Canada - National Science Library

    Kunzler, Marley; Udd, Eric; Kreger, Stephen; Johnson, Mont; Henrie, Vaughn

    2005-01-01

    .... Using fiber Bragg gratings embedded into the weave structure of carbon fiber epoxy composites allow the capability to monitor these composites during manufacture, cure, general aging, and damage...

  7. Composite nonlinear structure within the magnetosonic soliton interactions in a spin-1/2 degenerate quantum plasma

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jiu-Ning, E-mail: hanjiuning@126.com; Luo, Jun-Hua; Li, Jun-Xiu [Institute of Theoretical Physics and College of Physics and Electromechanical Engineering, Hexi University, Zhangye 734000 (China); Li, Sheng-Chang [School of Science, Xi' an Jiaotong University, Xi' an 710049 (China); Liu, Shi-Wei; Yang, Yang; Duan, Wen-Shan; Han, Juan-Fang [Joint Laboratory of Atomic and Molecular Physics of NWNU and IMPCAS and College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2015-06-15

    We study the basic physical properties of composite nonlinear structure induced by the head-on collision of magnetosonic solitons. Solitary waves are assumed to propagate in a quantum electron-ion magnetoplasma with spin-1/2 degenerate electrons. The main interest of the present work is to investigate the time evolution of the merged composite structure during a specific time interval of the wave interaction process. We consider three cases of colliding-situation, namely, compressive-rarefactive solitons interaction, compressive-compressive solitons interaction, and rarefactive-rarefactive solitons interaction, respectively. Compared with the last two colliding cases, the changing process of the composite structure is more complex for the first situation. Moreover, it is found that they are obviously different for the last two colliding cases.

  8. Synthesis on the durability of composite fiberglass/epoxy resin structures

    International Nuclear Information System (INIS)

    Thevenin, P.

    1997-01-01

    The purpose of this paper is to collect together in a systematic way information and results relating to the durability of composite fiberglass/ epoxy resin structures. First it is a matter of assessing the average level of understanding the long term behaviour of these structures which change under the combined effects of varied mechanical loading and stresses of a physico-chemical type linked to the environment. Looking at phenomena encountered and facts from current analyses, it will then be advisable to specify a methodology which can be applied to industrial piping used in PWR cooling systems for transporting raw water under pressure. In fact assessment of their service life is at present based on long and costly testing (ASTM D 2992 B standard), the appearance of which is inherited from metal piping testing.. Therefore it appears essential to study substitution test procedures, more composite specific and at the same time which can be conducted in reasonable time. For this purpose, by coherently accelerating and combining them in order not to underestimate their effects, ageing tests shall reproduce mechanisms representative of operating conditions. (author)

  9. Molecular and structural properties of polymer composites filled with activated charcoal particles

    Energy Technology Data Exchange (ETDEWEB)

    Tahir, Dahlang, E-mail: dtahir@fmipa.unhas.ac.id; Bakri, Fahrul [Department of Physics, Hasanuddin University, Makassar 90245 Indonesia (Indonesia); Liong, Syarifuddin [Department of Chemistry, Hasanuddin University, Makassar 90245 Indonesia (Indonesia)

    2016-03-11

    We have studied the molecular properties, structural properties, and chemical composition of composites by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) spectroscopy, and X-ray fluorescence (XRF) spectroscopy, respectively. FTIR spectra shows absorption band of hydroxyl group (-OH), methyl group (-CH{sub 3}) and aromatic group (C-C). The absorption band for aromatic group (C-C) shows the formation of carbonaceous in composites. XRF shows chemical composition of composites, which the main chemicals are SO{sub 3}, Cl, and ZnO. The loss on ignition value (LOI) of activated charcoal indicates high carbonaceous matter. The crystallite size for diffraction pattern from hydrogel polymer is about 17 nm and for activated charcoal are about 19 nm. The crystallite size of the polymer is lower than that of activated charcoal, which make possible of the particle from filler in contact with each other to form continuous conducting polymer through polymer matrix.

  10. Structural Analysis and Optimization of a Composite Fan Blade for Future Aircraft Engine

    Science.gov (United States)

    Coroneos, Rula M.; Gorla, Rama Subba Reddy

    2012-09-01

    This paper addresses the structural analysis and optimization of a composite sandwich ply lay-up of a NASA baseline solid metallic fan blade comparable to a future Boeing 737 MAX aircraft engine. Sandwich construction with a polymer matrix composite face sheet and honeycomb aluminum core replaces the original baseline solid metallic fan model made of Titanium. The focus of this work is to design the sandwich composite blade with the optimum number of plies for the face sheet that will withstand the combined pressure and centrifugal loads while the constraints are satisfied and the baseline aerodynamic and geometric parameters are maintained. To satisfy the requirements a sandwich construction for the blade is proposed with composite face sheets and a weak core made of honeycomb aluminum material. For aerodynamic considerations, the thickness of the core is optimized where as the overall blade thickness is held fixed in order not to alter the original airfoil geometry. Weight reduction is taken as the objective function by varying the core thickness of the blade within specified upper and lower bounds. Constraints are imposed on radial displacement limitations and ply failure strength. From the optimum design, the minimum number of plies, which will not fail, is back-calculated. The ply lay-up of the blade is adjusted from the calculated number of plies and final structural analysis is performed. Analyses were carried out by utilizing the OpenMDAO Framework, developed at NASA Glenn Research Center combining optimization with structural assessment.

  11. Multifunctional CNT-polymer composites for ultra-tough structural supercapacitors and desalination devices.

    Science.gov (United States)

    Benson, Jim; Kovalenko, Igor; Boukhalfa, Sofiane; Lashmore, David; Sanghadasa, Mohan; Yushin, Gleb

    2013-12-03

    Pulsed electrodeposition of polyaniline (PANI) allows the fabrication of flexible, electrically conductive, nonwoven PANI-carbon nanotube (PANI-CNT) composite fabrics. They possess specific tensile strength and a modulus of toughness higher than that of aluminum matrix composites, titanium and aluminum alloys, steels, and many other structural materials. Electrochemical tests show that these nanocomposites additionally offer excellent cycle stability and ion electro-sorption and storage properties. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. A novel pineapple-structured Si/TiO2 composite as anode material for lithium ion batteries

    International Nuclear Information System (INIS)

    Yan, Dong; Bai, Ying; Yu, Caiyan; Li, Xiaoge; Zhang, Weifeng

    2014-01-01

    Highlights: • Pineapple-structured Si/TiO 2 composite was firstly synthesized by a simple sol–gel method. • Pineapple-structured Si/TiO 2 composite exhibits the best cycling stability. • TiO 2 layer not only effectively inhibits the volume change of Si, but also contributes its electrochemical activity. - Abstract: Nanoscaled Si is successfully wrapped with different contents of nano-TiO 2 (the molar ratios of Si/TiO 2 composites are 1:1, 1:2, 1:3, 1:4 and 1:5, respectively) to form a novel pineapple structure. X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM) are utilized to characterize the structure, component, chemical environment and morphology of the composite. The investigation in cycling performances demonstrates that Si/TiO 2 with molar ratio of 1:4 exhibits the best cycling stability, with specific capacity of 593 mA h g −1 after 50 cycles at 0.1 C, much higher than those of the other composites and the pristine material. Cyclic voltammetry (CV) profiles are also measured and compared. It is believed that the outside TiO 2 particles act as buffer against the huge volume change of Si during repeated alloying and de-alloying, which explains the improved electrochemical performances

  13. Thermal properties of highly structured composite and aluminium sheets in an aerodynamic tunnel

    Science.gov (United States)

    Kulhavy, Petr; Egert, Josef

    This article deals with the thermodynamic behaviour of heat shields - structured metal and composite plates. Experiments have been carried out in a wind tunnel with an additional heating, which simulates the heat source from engine or exhaust pipe and simultaneously the airflow generated during a car movement. The tested sheets with hexagonal structure were a standard commercial made of aluminium and a second manufactured by replication (lamination, diffusion) from glass fabric. The airflow in a parallel way along the sheets was analysed experimentally in order to determine the heat transfer efficiency between surfaces of sheets and surrounding airflow. The temperature on the sheets was chosen to observe the effects of different sheets material, various heat power and airflow velocity. During the experiment a thermal input below the sheets and airflow velocity through the tunnel have been changed. The thermal field distribution on the metal sheet is different than in case of composite sheet. For the composite material the thermal field distribution was more homogeneous. This article describe briefly also methods of obtaining real composite geometry based on scanned data and their reconstruction for using in some future numerical models.

  14. Thermal properties of highly structured composite and aluminium sheets in an aerodynamic tunnel

    Directory of Open Access Journals (Sweden)

    Kulhavy Petr

    2017-01-01

    Full Text Available This article deals with the thermodynamic behaviour of heat shields - structured metal and composite plates. Experiments have been carried out in a wind tunnel with an additional heating, which simulates the heat source from engine or exhaust pipe and simultaneously the airflow generated during a car movement. The tested sheets with hexagonal structure were a standard commercial made of aluminium and a second manufactured by replication (lamination, diffusion from glass fabric. The airflow in a parallel way along the sheets was analysed experimentally in order to determine the heat transfer efficiency between surfaces of sheets and surrounding airflow. The temperature on the sheets was chosen to observe the effects of different sheets material, various heat power and airflow velocity. During the experiment a thermal input below the sheets and airflow velocity through the tunnel have been changed. The thermal field distribution on the metal sheet is different than in case of composite sheet. For the composite material the thermal field distribution was more homogeneous. This article describe briefly also methods of obtaining real composite geometry based on scanned data and their reconstruction for using in some future numerical models.

  15. Poling of PVDF matrix composites for integrated structural load sensing

    Science.gov (United States)

    Haghiashtiani, Ghazaleh; Greminger, Michael A.; Zhao, Ping

    2014-03-01

    The purpose of this study is to create and evaluate a smart composite structure that can be used for integrated load sensing and structural health monitoring. In this structure, PVDF films are used as the matrix material instead of epoxy resin or other thermoplastics. The reinforcements are two layers of carbon fiber with one layer of Kevlar separating them. Due to the electrical conductivity properties of carbon fiber and the dielectric effect of Kevlar, the structure acts as a capacitor. Furthermore, the piezoelectric properties of the PVDF matrix can be used to monitor the response of the structure under applied loads. In order to exploit the piezoelectric properties of PVDF, the PVDF material must be polarized to align the dipole moments of its crystalline structure. The optimal condition for poling the structure was found by performing a 23 factorial design of experiment (DoE). The factors that were studied in DoE were temperature, voltage, and duration of poling. Finally, the response of the poled structure was monitored by exposing the samples to an applied load.

  16. Effects of past burning frequency on plant species structure and composition in dry dipterocarp forest

    Science.gov (United States)

    Wanthongchai, Dr.; Bauhus, Prof.; Goldammer, Prof.

    2009-04-01

    Anthropogenic burning in dry dipterocarp forests (DDF) has become a common phenomenon throughout Thailand. It is feared that too frequent fires may affect vegetation structure and composition and thus impact on ecosystem productivity. The aim of this study was to quantify the effects of prescribed fires on sites with different past burning regimes on vegetation structure and composition in the Huay Kha Khaeng Wildlife Sanctuary (HKK), Thailand. Fire frequency was determined from satellite images and ranged from frequent, infrequent, rare and unburned with fire occurrences of 7, 2, 1 and 0 out of the past 10 years, respectively. The pre-burn fuel loads, the overstorey and understorey vegetation structure and composition were determined to investigate the effects of the contrasting past burning regimes. The burning experiment was carried out, applying a three-strip head-fire burning technique. The vegetation structure and composition were sampled again one year after the fire to assess the fire impacts. Aboveground fine fuel loads increased with the length of fire-free interval. The woody plant structures of the frequently burned stand differed from those of the other less frequently burned stands. The species composition of the overstorey on the frequently burned site, in particular that of small sized trees (4.5-10 cm dbh), also differed significantly from that of the other sites. Whilst the ground vegetation including shrubs and herbs did not differ between the past burning regimes, frequent burning obviously promoted the proliferation of graminoid vegetation. There was no clear evidence showing that the prescribed fires affected the mortality of trees (dbh> 4.5 cm) on the sites of the different past burning regimes. The effects of prescribed burning on the understorey vegetation structures varied between the past burning regimes and the understorey vegetation type. Therefore, it is recommended that the DDF at HKK should be subjected to a prescribed fire frequency

  17. A turtle-like swimming robot using a smart soft composite (SSC) structure

    International Nuclear Information System (INIS)

    Kim, Hyung-Jung; Song, Sung-Hyuk; Ahn, Sung-Hoon

    2013-01-01

    This paper describes the development of a biomimetic swimming robot based on the locomotion of a marine turtle. To realize the smooth, soft flapping motions of this type of turtle, a novel actuator was also developed, using a smart soft composite (SSC) structure that can generate bending and twisting motions in a simple, lightweight structure. The SSC structure is a composite consisting of an active component to generate the actuation force, a passive component to determine the twisting angle of the structure, and a matrix to combine the components. The motion of such a structure can be designed by specifying the angle between a filament of the scaffold structure and a shape-memory alloy (SMA) wire. The bending and twisting motion of the SSC structure is explained in terms of classical laminate theory, and cross-ply and angled-ply structures were fabricated to evaluate its motion. Finally, the turtle-like motion of a swimming robot was realized by employing a specially designed SSC structure. To mimic the posterior positive twisting angle of a turtle’s flipper during the upstroke, the SMA wire on the upper side was offset, and a positive ply-angled scaffold was used. Likewise, for the anterior negative twisting angle of the flipper during the downstroke, an offset SMA wire on the lower side and a positive ply-angled scaffold were also required. The fabricated flipper’s length is 64.3 mm and it realizes 55 mm bending and 24° twisting. The resulting robot achieved a swimming speed of 22.5 mm s −1 . (paper)

  18. Bamboo-Polylactic Acid (PLA) Composite Material for Structural Applications.

    Science.gov (United States)

    Pozo Morales, Angel; Güemes, Alfredo; Fernandez-Lopez, Antonio; Carcelen Valero, Veronica; De La Rosa Llano, Sonia

    2017-11-09

    Developing an eco-friendly industry based on green materials, sustainable technologies, and optimum processes with low environmental impact is a general societal goal, but this remains a considerable challenge to achieve. Despite the large number of research on green structural composites, limited investigation into the most appropriate manufacturing methodology to develop a structural material at industrial level has taken place. Laboratory panels have been manufactured with different natural fibers but the methodologies and values obtained could not be extrapolated at industrial level. Bamboo industry panels have increased in the secondary structural sector such as building application, flooring and sport device, because it is one of the cheapest raw materials. At industrial level, the panels are manufactured with only the inner and intermediate region of the bamboo culm. However, it has been found that the mechanical properties of the external shells of bamboo culm are much better than the average cross-sectional properties. Thin strips of bamboo (1.5 mm thick and 1500 mm long) were machined and arranged with the desired lay-up and shape to obtain laminates with specific properties better than those of conventional E-Glass/Epoxy laminates in terms of both strength and stiffness. The strips of bamboo were bonded together by a natural thermoplastic polylactic acid (PLA) matrix to meet biodegradability requirements. The innovative mechanical extraction process developed in this study can extract natural strip reinforcements with high performance, low cost, and high rate, with no negative environmental impact, as no chemical treatments are used. The process can be performed at the industrial level. Furthermore, in order to validate the structural applications of the composite, the mechanical properties were analyzed under ageing conditions. This material could satisfy the requirements for adequate mechanical properties and life cycle costs at industrial sectors such

  19. Bamboo–Polylactic Acid (PLA Composite Material for Structural Applications

    Directory of Open Access Journals (Sweden)

    Angel Pozo Morales

    2017-11-01

    Full Text Available Developing an eco-friendly industry based on green materials, sustainable technologies, and optimum processes with low environmental impact is a general societal goal, but this remains a considerable challenge to achieve. Despite the large number of research on green structural composites, limited investigation into the most appropriate manufacturing methodology to develop a structural material at industrial level has taken place. Laboratory panels have been manufactured with different natural fibers but the methodologies and values obtained could not be extrapolated at industrial level. Bamboo industry panels have increased in the secondary structural sector such as building application, flooring and sport device, because it is one of the cheapest raw materials. At industrial level, the panels are manufactured with only the inner and intermediate region of the bamboo culm. However, it has been found that the mechanical properties of the external shells of bamboo culm are much better than the average cross-sectional properties. Thin strips of bamboo (1.5 mm thick and 1500 mm long were machined and arranged with the desired lay-up and shape to obtain laminates with specific properties better than those of conventional E-Glass/Epoxy laminates in terms of both strength and stiffness. The strips of bamboo were bonded together by a natural thermoplastic polylactic acid (PLA matrix to meet biodegradability requirements. The innovative mechanical extraction process developed in this study can extract natural strip reinforcements with high performance, low cost, and high rate, with no negative environmental impact, as no chemical treatments are used. The process can be performed at the industrial level. Furthermore, in order to validate the structural applications of the composite, the mechanical properties were analyzed under ageing conditions. This material could satisfy the requirements for adequate mechanical properties and life cycle costs at

  20. Bamboo–Polylactic Acid (PLA) Composite Material for Structural Applications

    Science.gov (United States)

    Pozo Morales, Angel; Güemes, Alfredo; Fernandez-Lopez, Antonio; Carcelen Valero, Veronica; De La Rosa Llano, Sonia

    2017-01-01

    Developing an eco-friendly industry based on green materials, sustainable technologies, and optimum processes with low environmental impact is a general societal goal, but this remains a considerable challenge to achieve. Despite the large number of research on green structural composites, limited investigation into the most appropriate manufacturing methodology to develop a structural material at industrial level has taken place. Laboratory panels have been manufactured with different natural fibers but the methodologies and values obtained could not be extrapolated at industrial level. Bamboo industry panels have increased in the secondary structural sector such as building application, flooring and sport device, because it is one of the cheapest raw materials. At industrial level, the panels are manufactured with only the inner and intermediate region of the bamboo culm. However, it has been found that the mechanical properties of the external shells of bamboo culm are much better than the average cross-sectional properties. Thin strips of bamboo (1.5 mm thick and 1500 mm long) were machined and arranged with the desired lay-up and shape to obtain laminates with specific properties better than those of conventional E-Glass/Epoxy laminates in terms of both strength and stiffness. The strips of bamboo were bonded together by a natural thermoplastic polylactic acid (PLA) matrix to meet biodegradability requirements. The innovative mechanical extraction process developed in this study can extract natural strip reinforcements with high performance, low cost, and high rate, with no negative environmental impact, as no chemical treatments are used. The process can be performed at the industrial level. Furthermore, in order to validate the structural applications of the composite, the mechanical properties were analyzed under ageing conditions. This material could satisfy the requirements for adequate mechanical properties and life cycle costs at industrial sectors such