77 FR 5440 - Withdrawal of Regulations Pertaining to Imports of Cotton Woven Fabric and Short Supply...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-03

...-AA90 Withdrawal of Regulations Pertaining to Imports of Cotton Woven Fabric and Short Supply Procedures... for the purpose of withdrawing regulations pertaining to imports of cotton woven fabric and short... ``Comments on proposed Withdrawal of Regulations Pertaining to Imports of Cotton Woven Fabric and Short...

Mechanics of fiber reinforced materials

NASA Astrophysics Data System (ADS)

Sun, Huiyu

This dissertation is dedicated to mechanics of fiber reinforced materials and the woven reinforcement and composed of four parts of research: analytical characterization of the interfaces in laminated composites; micromechanics of braided composites; shear deformation, and Poisson's ratios of woven fabric reinforcements. A new approach to evaluate the mechanical characteristics of interfaces between composite laminae based on a modified laminate theory is proposed. By including an interface as a special lamina termed the "bonding-layer" in the analysis, the mechanical properties of the interfaces are obtained. A numerical illustration is given. For micro-mechanical properties of three-dimensionally braided composite materials, a new method via homogenization theory and incompatible multivariable FEM is developed. Results from the hybrid stress element approach compare more favorably with the experimental data than other existing numerical methods widely used. To evaluate the shearing properties for woven fabrics, a new mechanical model is proposed during the initial slip region. Analytical results show that this model provides better agreement with the experiments for both the initial shear modulus and the slipping angle than the existing models. Finally, another mechanical model for a woven fabric made of extensible yarns is employed to calculate the fabric Poisson's ratios. Theoretical results are compared with the available experimental data. A thorough examination on the influences of various mechanical properties of yarns and structural parameters of fabrics on the Poisson's ratios of a woven fabric is given at the end.

DRAPING SIMULATION OF WOVEN FABRICS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodgers, William; Jin, Xiaoshi; Zhu, Jiang

2016-09-07

Woven fabric composites are extensively used in molding complex geometrical shapes due to their high conformability compared to other fabrics. Preforming is an important step in the overall process, where the two-dimensional fabric is draped to become the three-dimensional shape of the part prior to resin injection. During preforming, the orientation of the yarns may change significantly compared to the initial orientations. Accurate prediction of the yarn orientations after molding is important for evaluating the structural performance of the final part. This paper presents a systematic investigation of the angle changes during the preform operation for carbon fiber twill andmore » satin weave fabrics. Preforming experiments were conducted using a truncated pyramid mold geometry designed and fabricated at the General Motors Research Laboratories. Predicted results for the yarn orientations were compared with experimental results and good agreement was observed« less

Multi Length Scale Finite Element Design Framework for Advanced Woven Fabrics

NASA Astrophysics Data System (ADS)

Erol, Galip Ozan

Woven fabrics are integral parts of many engineering applications spanning from personal protective garments to surgical scaffolds. They provide a wide range of opportunities in designing advanced structures because of their high tenacity, flexibility, high strength-to-weight ratios and versatility. These advantages result from their inherent multi scale nature where the filaments are bundled together to create yarns while the yarns are arranged into different weave architectures. Their highly versatile nature opens up potential for a wide range of mechanical properties which can be adjusted based on the application. While woven fabrics are viable options for design of various engineering systems, being able to understand the underlying mechanisms of the deformation and associated highly nonlinear mechanical response is important and necessary. However, the multiscale nature and relationships between these scales make the design process involving woven fabrics a challenging task. The objective of this work is to develop a multiscale numerical design framework using experimentally validated mesoscopic and macroscopic length scale approaches by identifying important deformation mechanisms and recognizing the nonlinear mechanical response of woven fabrics. This framework is exercised by developing mesoscopic length scale constitutive models to investigate plain weave fabric response under a wide range of loading conditions. A hyperelastic transversely isotropic yarn material model with transverse material nonlinearity is developed for woven yarns (commonly used in personal protection garments). The material properties/parameters are determined through an inverse method where unit cell finite element simulations are coupled with experiments. The developed yarn material model is validated by simulating full scale uniaxial tensile, bias extension and indentation experiments, and comparing to experimentally observed mechanical response and deformation mechanisms. Moreover

Magnetic properties of electrospun non-woven superconducting fabrics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koblischka, Michael R.; Zeng, Xian Lin; Karwoth, Thomas

2016-03-15

Non-woven superconducting fabrics were prepared by the electrospinning technique, consisting of Bi{sub 2}Sr{sub 2}CaCuO{sub 8} (Bi-2212) nanowires. The individual nanowires have a diameter of ∼150-200 nm and lengths of up to 100 μm. A non-woven fabric forming a network with a large number of interconnects results, which enables the flow of transport currents through the entire network. We present here magnetization data [M(T) and M(H)-loops] of this new class of superconducting material. The magnetic properties of these nanowire networks are discussed including the irreversibility line and effects of different field sweep rates, regarding the microstructure of the nanowire networks investigatedmore » by electron microscopy.« less

Composite panels based on woven sandwich-fabric preforms

NASA Astrophysics Data System (ADS)

van Vuure, Aart Willem

A new type of sandwich material was investigated, based on woven sandwich-fabric preforms. Because of the integrally woven nature of the sandwich-fabric the skin-core debonding resistance of panels and structures based on the preform is very high. As the sandwich-fabrics are produced by a large scale textile weaving process (velvet weaving or distance weaving) and already a preform of a sandwich is available, the cost of the final panel or structure can potentially stay limited. Most attention in this work is focussed on the mechanical performance of sandwich-fabric panels. The high skin-core debonding resistance was verified and also indications were found of a good damage tolerance. Both unfoamed and foamed panels were evaluated and compared with existing sandwich panels. Microstructural parameters investigated for unfoamed cores are pile length, pile density, woven pile angles, degree of pile stretching, tilt angles of the piles induced during panel production and resin content and distribution. For foamed panels it is especially the foam density which has an important influence. There appears to be a synergistic effect between piles and foam in the sandwich core, leading to very acceptable mechanical properties. For panels for (semi) structural applications, foaming is almost indispensable once the panel thickness is higher than about 15 mm. To understand the behaviour of foamed panels, attention was paid to the modelling of the mechanics of pure foam. The foam microstructure was modelled with the model of an anisotropic tetrakaidecahedron. The mechanical properties of unfoamed panels were modelled with the help of finite elements. A detailed geometrical description of the core layout was made which was incorporated into a preprocessing program for a finite element code. Attention is paid to the production of panels based on the woven preforms. A newly developed Adhesive Foil Stretching process was investigated. Also the foaming of panels was studied. A lot of

Influence of the Geometric Parameters on the Mechanical Behaviour of Fabric Reinforced Composite Laminates

NASA Astrophysics Data System (ADS)

Axinte, Andrei; Taranu, Nicolae; Bejan, Liliana

2016-10-01

A polymer fabric reinforced composite is a high performance material, which combines strength of the fibres with the flexibility and ductility of the matrix. For a better drapeability, the tows of fibres are interleaved, resulting the woven fabric, used as reinforcement. The complex geometric shape of the fabric is of paramount importance in establishing the deformability of the textile reinforced composite laminates. In this paper, an approach based on Classical Lamination Theory ( CLT), combined with Finite Element Methods ( FEM), using Failure Analysis and Internal Load Redistribution, is utilised, in order to compare the behaviour of the material under specific loads. The main goal is to analyse the deformability of certain types of textile reinforced composite laminates, using carbon fibre satin as reinforcement and epoxy resin as matrix. This is accomplished by studying the variation of the in-plane strains, given the fluctuation of several geometric parameters, namely the width of the reinforcing tow, the gap between two consecutive tows, the angle of laminae in a multi-layered configuration and the tows fibre volume fraction.

Mechanical properties of reinforced denture base resin: the effect of position and the number of woven glass fibers.

PubMed

Kanie, Takahito; Arikawa, Hiroyuki; Fujii, Koichi; Ban, Seiji

2002-09-01

This study examined the effects of the position and the number of woven glass fibers on the flexural strength, flexural modulus, and toughness of reinforced denture base resin. The woven glass fiber consisted of 1-4 laminated sheets. Chemical curing was used to polymerize three types of 4-mm-thick test specimens: fibers in compresrion, fibers in the center, and fibers in tension. Unreinforced specimens were produced as controls. A three-point flexural test was performed and the woven glass fiber content was calculated after the woven glass fiber was fired. The best results were obtained when the woven glass fiber was incorporated outside the base resin under tension, thereby increasing the flexural strength and flexural modulus. Furthermore, the denture base resin reinforced with woven glass fiber was made tougher by increasing the number of woven glass fibers incorporated into the portion under tension.

Assessment of solvent capsule-based healing for woven E-glass fibre-reinforced polymers

NASA Astrophysics Data System (ADS)

Manfredi, Erica; Cohades, Amaël; Richard, Inès; Michaud, Véronique

2015-01-01

Vacuum Assisted Resin Infusion Molding (VARIM) with low vacuum pressure difference was used to manufacture woven glass fibre-reinforced epoxy resin plates, with a fibre volume fraction of approx. 50 vol% and containing ethyl phenylacetate (EPA)-filled capsules for self-healing purposes. Capsules were introduced by functionalising the fabrics through manual dispersion. We investigated the capability of autonomously healing delaminations induced by static loading in Mode I and II. Healing did not take place for composite samples; this was attributed to the presence of bare fibres on the crack plane and to the reduction of EPA diffusion into the matrix in the presence of fibres both of which hinder the swelling mechanism responsible for healing the cracks.

Influence of laminate sequence and fabric type on the inherent acoustic nonlinearity in carbon fiber reinforced composites.

PubMed

Chakrapani, Sunil Kishore; Barnard, Daniel J; Dayal, Vinay

2016-05-01

This paper presents the study of influence of laminate sequence and fabric type on the baseline acoustic nonlinearity of fiber-reinforced composites. Nonlinear elastic wave techniques are increasingly becoming popular in detecting damage in composite materials. It was earlier observed by the authors that the non-classical nonlinear response of fiber-reinforced composite is influenced by the fiber orientation [Chakrapani, Barnard, and Dayal, J. Acoust. Soc. Am. 137(2), 617-624 (2015)]. The current study expands this effort to investigate the effect of laminate sequence and fabric type on the non-classical nonlinear response. Two hypotheses were developed using the previous results, and the theory of interlaminar stresses to investigate the influence of laminate sequence and fabric type. Each hypothesis was tested by capturing the nonlinear response by performing nonlinear resonance spectroscopy and measuring frequency shifts, loss factors, and higher harmonics. It was observed that the laminate sequence can either increase or decrease the nonlinear response based on the stacking sequence. Similarly, tests were performed to compare unidirectional fabric and woven fabric and it was observed that woven fabric exhibited a lower nonlinear response compared to the unidirectional fabric. Conjectures based on the matrix properties and interlaminar stresses were used in an attempt to explain the observed nonlinear responses for different configurations.

Preparation of new natural silk non-woven fabrics by using adhesion characteristics of sericin and their characterization.

PubMed

Lee, Ji Hye; Bae, Yeon Su; Kim, Su Jin; Song, Dae Woong; Park, Young Hwan; Bae, Do Gyu; Choi, Jin Hyun; Um, In Chul

2018-01-01

Electro-spun regenerated silk webs have been extensively studied for biomedical applications because of the simplicity of their fabrication methods However, the productivity of the electro-spinning process is low for web fabrication and the mechanical properties of the electro-spun silk web are not satisfactory, which restricts its commercialization. In this study, a new silk non-woven fabric was successfully fabricated by wetting and hot press treatments using the excellent binding characteristic of sericin. The effects of the press temperature and residual sericin content on the preparation, structure, and properties of the silk non-woven fabric were examined. A press temperature of 200°C was optimum for obtaining non-woven fabrics with best mechanical properties, without yellowing. The silk non-woven fabric could not be fabricated without sericin, and a minimum of 8% sericin was required to fabricate it. As the sericin content was increased, the strength and Young's modulus of the silk non-woven fabric increased, while the tensile elongation remained constant. Regardless of the press temperature and sericin content, all the silk non-woven fabrics showed good cell viability, comparable to that of the tissue culture plate (TCP) used as a control until 4days, which however decreased compared to that of TCP after 7days. Copyright © 2017 Elsevier B.V. All rights reserved.

Hybrid composite laminates reinforced with Kevlar/carbon/glass woven fabrics for ballistic impact testing.

PubMed

Randjbaran, Elias; Zahari, Rizal; Jalil, Nawal Aswan Abdul; Majid, Dayang Laila Abang Abdul

2014-01-01

Current study reported a facile method to investigate the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption by running the ballistic test at the high velocity ballistic impact conditions. The velocity and absorbed energy were accordingly calculated as well. The specimens were fabricated from Kevlar, carbon, and glass woven fabrics and resin and were experimentally investigated under impact conditions. All the specimens possessed equal mass, shape, and density; nevertheless, the layers were ordered in different stacking sequence. After running the ballistic test at the same conditions, the final velocities of the cylindrical AISI 4340 Steel pellet showed how much energy was absorbed by the samples. The energy absorption of each sample through the ballistic impact was calculated; accordingly, the proper ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterise the material properties for the different layers.

Hybrid Composite Laminates Reinforced with Kevlar/Carbon/Glass Woven Fabrics for Ballistic Impact Testing

PubMed Central

Randjbaran, Elias; Zahari, Rizal; Abdul Jalil, Nawal Aswan; Abang Abdul Majid, Dayang Laila

2014-01-01

Current study reported a facile method to investigate the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption by running the ballistic test at the high velocity ballistic impact conditions. The velocity and absorbed energy were accordingly calculated as well. The specimens were fabricated from Kevlar, carbon, and glass woven fabrics and resin and were experimentally investigated under impact conditions. All the specimens possessed equal mass, shape, and density; nevertheless, the layers were ordered in different stacking sequence. After running the ballistic test at the same conditions, the final velocities of the cylindrical AISI 4340 Steel pellet showed how much energy was absorbed by the samples. The energy absorption of each sample through the ballistic impact was calculated; accordingly, the proper ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterise the material properties for the different layers. PMID:24955400

Physical properties of recycled PET non-woven fabrics for buildings

NASA Astrophysics Data System (ADS)

Üstün Çetin, S.; Tayyar, A. E.

2017-10-01

Recycled fibers have been commonly used in non-woven production technology for engineering applications such as textile engineering and civil engineering. Nonwovens including recycled fibers can be utilized in insulation, roofing and floor separation applications. In this study, physical performance properties such as drape, bending resistance, tensile strength, and breaking elongation values of non-woven fabrics consisting of v-PET (virgin) and r-PET (recycled) fibers in five different blend ratios are examined comparatively. The test results indicated that r-PET can be used in non-wovens for civil engineering applications such as insulation, roofing and floor separation fulfilling the acceptable quality level values.

Vertically aligned TiO2 nanorods-woven carbon fiber for reinforcement of both mechanical and anti-wear properties in resin composite

NASA Astrophysics Data System (ADS)

Fei, Jie; Zhang, Chao; Luo, Dan; Cui, Yali; Li, Hejun; Lu, Zhaoqing; Huang, Jianfeng

2018-03-01

A series of TiO2 nanorods were successfully grown on woven carbon fiber by hydrothermal method to reinforce the resin composite. The TiO2 nanorods improved the mechanical interlocking among woven carbon fibers and resin matrix, resulting in better fibers/resin interfacial bonding. Compared with desized-woven carbon fiber, the uniform TiO2 nanorods array resulted in an improvement of 84.3% and 73.9% in the tensile and flexural strength of the composite. However, the disorderly TiO2 nanorods on woven carbon fiber leaded to an insignificant promotion of the mechanical strength. The enhanced performance of well-proportioned TiO2 nanorods-woven carbon fiber was also reflected in the nearly 56% decrease of wear rate, comparing to traditional woven carbon fiber reinforced composite.

Static Strength of Adhesively-bonded Woven Fabric Kenaf Composite Plates

NASA Astrophysics Data System (ADS)

Hilton, Ahmad; Lee, Sim Yee; Supar, Khairi

2017-06-01

Natural fibers are potentially used as reinforcing materials and combined with epoxy resin as matrix system to form a superior specific strength (or stiffness) materials known as composite materials. The advantages of implementing natural fibers such as kenaf fibers are renewable, less hazardous during fabrication and handling process; and relatively cheap compared to synthetic fibers. The aim of current work is to conduct a parametric study on static strength of adhesively bonded woven fabric kenaf composite plates. Fabrication of composite panels were conducted using hand lay-up techniques, with variation of stacking sequence, over-lap length, joint types and lay-up types as identified in testing series. Quasi-static testing was carried out using mechanical testing following code of practice. Load-displacement profiles were analyzed to study its structural response prior to ultimate failures. It was found that cross-ply lay-up demonstrates better static strength compared to quasi-isotropic lay-up counterparts due to larger volume of 0° plies exhibited in cross-ply lay-up. Consequently, larger overlap length gives better joining strength, as expected, however this promotes to weight penalty in the joining structure. Most samples showed failures within adhesive region known as cohesive failure modes, however, few sample demonstrated interface failure. Good correlations of parametric study were found and discussed in the respective section.

The Improvement of the Resistance to Candida albicans and Trichophyton interdigitale of Some Woven Fabrics Based on Cotton.

PubMed

Surdu, Lilioara; Stelescu, Maria Daniela; Manaila, Elena; Nicula, Gheorghe; Iordache, Ovidiu; Dinca, Laurentiu Christian; Berechet, Mariana-Daniela; Vamesu, Mariana; Gurau, Dana

2014-01-01

This paper presents the improvement of the antimicrobial character of woven fabrics based on cotton. The woven fabrics were cleaned in oxygen plasma and treated by padding with silver chloride and titanium dioxide particles. The existence of silver and titanium on woven fabrics was evidenced by electronic microscope images (SEM, EDAX) and by flame atomic absorption spectrophotometry. The antimicrobial tests were performed with two fungi: Candida albicans and Trichophyton interdigitale. The obtained antimicrobial effect was considerably higher compared to the raw fabrics. Treatment of dyed fabrics with a colloidal solution based on silver chloride and titanium dioxide particles does not considerably influence colour resistance of dyes.

The Improvement of the Resistance to Candida albicans and Trichophyton interdigitale of Some Woven Fabrics Based on Cotton

PubMed Central

Stelescu, Maria Daniela; Manaila, Elena; Nicula, Gheorghe; Iordache, Ovidiu; Dinca, Laurentiu Christian; Berechet, Mariana-Daniela; Vamesu, Mariana; Gurau, Dana

2014-01-01

This paper presents the improvement of the antimicrobial character of woven fabrics based on cotton. The woven fabrics were cleaned in oxygen plasma and treated by padding with silver chloride and titanium dioxide particles. The existence of silver and titanium on woven fabrics was evidenced by electronic microscope images (SEM, EDAX) and by flame atomic absorption spectrophotometry. The antimicrobial tests were performed with two fungi: Candida albicans and Trichophyton interdigitale. The obtained antimicrobial effect was considerably higher compared to the raw fabrics. Treatment of dyed fabrics with a colloidal solution based on silver chloride and titanium dioxide particles does not considerably influence colour resistance of dyes. PMID:25276112

Physical properties of ZrC/Al2O3 imbedded heat storage woven fabrics

NASA Astrophysics Data System (ADS)

Kim, S. J.; Song, M. K.; Seo, K. O.; Kim, H. A.

2017-10-01

This study investigated different physical properties of ZrC/Al2O3 imbedded heat storage woven fabrics. ZrC and Al2O3 imbedded heat storage PET filaments were spun on the pilot spinning equipment, respectively. Various physical properties of ceramic imbedded fabrics made of ZrC and Al2O3 imbedded filaments were measured and compared with those of the regular PET woven fabric. The surface temperatures of the ZrC and Al2O3 imbedded fabrics were higher than that of the regular fabric. Water absorption rate of ceramic imbedded fabrics was better than that of the regular fabric and drying property was inferior to that of regular fabric. Breathability by water vapour resistance(Ref) of ZrC imbedded fabric was superior to that of regular fabric. Heat keepability rates of the ceramic imbedded fabrics were higher than that of the regular fabrics, which revealed a good heat storage property of the ZrC/Al2O3 imbedded fabrics.

Experimental analysis of in plane shear behaviour of woven composite reinforcements. Influence of tensions

NASA Astrophysics Data System (ADS)

Launay, Jean; Hivet, Gilles; Vu Duong, Ahn; Boisse, Philippe

2007-04-01

Two tests are mainly used to identify the shear behavior of fabrics. The "picture frame" which uses a lozenge framework made of four rigid and articulated bars and the "bias test" which is a tensile test on a sample with initially a 45° angle between the yarns and the edges. The picture frame test is the more commonly used because the whole specimen is theoretically in a pure shear state. Nevertheless the absence of tension in the woven reinforcement supposes a perfect alignment of fibres and positioning of the clamping point with regards to the framework articulations. In addition, it is often necessary in practice to impose an initial tension which is not quantified and whose consequences are ignored in the classical picture frame test. An experimental device making it possible to measure the tensions during the test is carried out. Different types of teste on different fabrics have been performed. Results presented here concern a twintex fabric that has been selected for a shear benchmark Thanks to this device, it is shown that tensions play an important role in plane shear behaviour.

Highly sensitive, self-powered and wearable electronic skin based on pressure-sensitive nanofiber woven fabric sensor.

PubMed

Zhou, Yuman; He, Jianxin; Wang, Hongbo; Qi, Kun; Nan, Nan; You, Xiaolu; Shao, Weili; Wang, Lidan; Ding, Bin; Cui, Shizhong

2017-10-11

The wearable electronic skin with high sensitivity and self-power has shown increasing prospects for applications such as human health monitoring, robotic skin, and intelligent electronic products. In this work, we introduced and demonstrated a design of highly sensitive, self-powered, and wearable electronic skin based on a pressure-sensitive nanofiber woven fabric sensor fabricated by weaving PVDF electrospun yarns of nanofibers coated with PEDOT. Particularly, the nanofiber woven fabric sensor with multi-leveled hierarchical structure, which significantly induced the change in contact area under ultra-low load, showed combined superiority of high sensitivity (18.376 kPa -1 , at ~100 Pa), wide pressure range (0.002-10 kPa), fast response time (15 ms) and better durability (7500 cycles). More importantly, an open-circuit voltage signal of the PPNWF pressure sensor was obtained through applying periodic pressure of 10 kPa, and the output open-circuit voltage exhibited a distinct switching behavior to the applied pressure, indicating the wearable nanofiber woven fabric sensor could be self-powered under an applied pressure. Furthermore, we demonstrated the potential application of this wearable nanofiber woven fabric sensor in electronic skin for health monitoring, human motion detection, and muscle tremor detection.

Analytical assessment of woven fabrics under vertical stabbing - The role of protective clothing.

PubMed

Hejazi, Sayyed Mahdi; Kadivar, Nastaran; Sajjadi, Ali

2016-02-01

Knives are being used more commonly in street fights and muggings. Therefore, this work presents an analytical model for woven fabrics under vertical stabbing loads. The model is based on energy method and the fabric is assumed to be unidirectional comprised of N layers. Thus, the ultimate stab resistance of fabric was determined based on structural parameters of fabric and geometrical characteristics of blade. Moreover, protective clothing is nowadays considered as a strategic branch in technical textile industry. The main idea of the present work is improving the stab resistance of woven textiles by using metal coating method. In the final, a series of vertical stabbing tests were conducted on cotton, polyester and polyamide fabrics. Consequently, it was found that the model predicts with a good accuracy the ultimate stab resistance of the sample fabrics. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Attachment of Poly(l-lactide) Nanoparticles to Plasma-Treated Non-Woven Polymer Fabrics Using Inkjet Printing.

PubMed

Ivanova, Tatiana V; Baier, Grit; Landfester, Katharina; Musin, Eduard; Al-Bataineh, Sameer A; Cameron, David C; Homola, Tomáš; Whittle, Jason D; Sillanpää, Mika

2015-09-01

Active dressings that based on fabric materials are an area of interest for the treatment of wounds. Poly(l-lactide) nanoparticles containing the antimicrobial agent octenidine can be controllably lysed by toxins released by pathogenic bacteria thus releasing antimicrobial material in response to the presence of the bacterial toxins and so counteracting the infection. We developed an integrated engineering solution that allows for the stable immobilisation of nanoparticles on non-woven fabrics. The process involves coating nanoparticles on non-woven polymer surfaces by using an inkjet printing process. In order to improve the adhesion and retention of the nanoparticles on the fabric, surface pretreatment of the non-woven fabric using plasma jet treatment can be applied to increase its surface energy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

77 FR 31182 - Final Withdrawal of Regulations Pertaining to Imports of Cotton Woven Fabric and Short Supply...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-25

... No. 120117047-2421-02] RIN 0625-AA90 Final Withdrawal of Regulations Pertaining to Imports of Cotton... final rule withdrawing regulations pertaining to imports of cotton woven fabric and short supply procedures. Both sets of regulations are obsolete: The tariff quota on cotton woven fabric expired in 2009...

Multifunctional non-woven fabrics of interfused graphene fibres

PubMed Central

Li, Zheng; Xu, Zhen; Liu, Yingjun; Wang, Ran; Gao, Chao

2016-01-01

Carbon-based fibres hold promise for preparing multifunctional fabrics with electrical conductivity, thermal conductivity, permeability, flexibility and lightweight. However, these fabrics are of limited performance mainly because of the weak interaction between fibres. Here we report non-woven graphene fibre fabrics composed of randomly oriented and interfused graphene fibres with strong interfibre bonding. The all-graphene fabrics obtained through a wet-fusing assembly approach are porous and lightweight, showing high in-plane electrical conductivity up to ∼2.8 × 104 S m−1 and prominent thermal conductivity of ∼301.5 W m−1 K−1. Given the low density (0.22 g cm−3), their specific electrical and thermal conductivities set new records for carbon-based papers/fabrics and even surpass those of individual graphene fibres. The as-prepared fabrics are further used as ultrafast responding electrothermal heaters and durable oil-adsorbing felts, demonstrating their great potential as high-performance and multifunctional fabrics in real-world applications. PMID:27901022

Geometrical analysis of woven fabric microstructure based on micron-resolution computed tomography data

NASA Astrophysics Data System (ADS)

Krieger, Helga; Seide, Gunnar; Gries, Thomas; Stapleton, Scott E.

2018-04-01

The global mechanical properties of textiles such as elasticity and strength, as well as transport properties such as permeability depend strongly on the microstructure of the textile. Textiles are heterogeneous structures with highly anisotropic material properties, including local fiber orientation and local fiber volume fraction. In this paper, an algorithm is presented to generate a virtual 3D-model of a woven fabric architecture with information about the local fiber orientation and the local fiber volume fraction. The geometric data of the woven fabric impregnated with resin was obtained by micron-resolution computed tomography (μCT). The volumetric μCT-scan was discretized into cells and the microstructure of each cell was analyzed and homogenized. Furthermore, the discretized data was used to calculate the local permeability tensors of each cell. An example application of the analyzed data is the simulation of the resin flow through a woven fabric based on the determined local permeability tensors and on Darcy's law. The presented algorithm is an automated and robust method of going from μCT-scans to structural or flow models.

Room- and Low-Temperature Deformation of Multilayered Fiberglass Plastics Reinforced with a Fabric of Sateen Weave

NASA Astrophysics Data System (ADS)

Kucher, N. K.; Dveyrin, A. Z.; Zarazovskii, M. N.; Zemtsov, M. P.

2004-05-01

The regularities of elastic deformation of multilayered fiberglass plastics reinforced with a fabric of sateen weave are studied. The effect of cooling to 77 K on the averaged elastic characteristics of the orthotropic material is analyzed. The efficiency of mathematical modeling in calculating the stiffness and compliance parameters of the woven composites based on the geometry and mechanical properties of their constituents is investigated.

Modeling the Stress Strain Behavior of Woven Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Morscher, Gregory N.

2006-01-01

Woven SiC fiber reinforced SiC matrix composites represent one of the most mature composite systems to date. Future components fabricated out of these woven ceramic matrix composites are expected to vary in shape, curvature, architecture, and thickness. The design of future components using woven ceramic matrix composites necessitates a modeling approach that can account for these variations which are physically controlled by local constituent contents and architecture. Research over the years supported primarily by NASA Glenn Research Center has led to the development of simple mechanistic-based models that can describe the entire stress-strain curve for composite systems fabricated with chemical vapor infiltrated matrices and melt-infiltrated matrices for a wide range of constituent content and architecture. Several examples will be presented that demonstrate the approach to modeling which incorporates a thorough understanding of the stress-dependent matrix cracking properties of the composite system.

Mechanical and Tear Properties of Fabric/Film Laminates

NASA Technical Reports Server (NTRS)

Said, Magdi A.

1998-01-01

Films reinforced with woven fabrics are being considered for the development of a material suitable for long duration scientific balloons under a program managed by the National Aeronautics and Space Administration (NASA). Recently developed woven fabrics provide a relatively high strength to weight ratio compared to standard homogenous films. Woven fabrics also have better crack propagation resistance and rip stop capabilities when compared to homogenous lightweight, high strength polymeric films such as polyester and nylon. If joining is required, such as in the case of scientific balloons, woven fabrics have the advantage over polymeric thin films to utilize traditional textile methods as well as other techniques including hot sealing, adhesion, and ultrasonic means. Woven fabrics, however, lack the barrier properties required for helium filled scientific balloons, therefore lamination with homogenous films is required to provide the gas barrier capabilities required in these applications.

Effect of a non-woven fabric covering on the residual activity of pendimethalin in lettuce and soil.

PubMed

Jursík, Miroslav; Kováčová, Jana; Kočárek, Martin; Hamouzová, Kateřina; Soukup, Josef

2017-05-01

Lettuce (Lactuca sativa L.) is a crop that is very sensitive to herbicide contamination owing to its short growing season. The use of long-residual herbicides and non-woven fabric coverings could therefore influence pendimethalin concentrations in soil and lettuce. The pendimethalin half-life in soil ranged between 18 and 85 days and was mainly affected by season (i.e. weather), and especially by soil moisture. Pendimethalin degradation in soil was slowest under dry conditions. A longer pendimethalin half-life was observed under the non-woven fabric treatment, but the effect of varying application rate was not significant. Pendimethalin residue concentrations in lettuce heads were significantly influenced by pendimethalin application rate and by non-woven fabric cover, especially at the lettuce's early growth stages. The highest pendimethalin concentration at final harvest was determined in lettuce grown on uncovered plots treated with pendimethalin at an application rate of 1200 g ha -1 (7-38 µg kg -1 ). Depending on growing season duration and weather conditions, pendimethalin concentrations in lettuce grown under non-woven fabric ranged from 0 to 21 µg kg -1 . Use of transparent non-woven fabric cover with lettuce can help to reduce application rates of soil herbicides and diminish the risk of herbicide contamination in the harvested vegetables. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Finite Element Simulation of Compression Molding of Woven Fabric Carbon Fiber/Epoxy Composites: Part I Material Model Development

DOE PAGES

Li, Yang; Zhao, Qiangsheng; Mirdamadi, Mansour; ...

2016-01-06

Woven fabric carbon fiber/epoxy composites made through compression molding are one of the promising choices of material for the vehicle light-weighting strategy. Previous studies have shown that the processing conditions can have substantial influence on the performance of this type of the material. Therefore the optimization of the compression molding process is of great importance to the manufacturing practice. An efficient way to achieve the optimized design of this process would be through conducting finite element (FE) simulations of compression molding for woven fabric carbon fiber/epoxy composites. However, performing such simulation remains a challenging task for FE as multiple typesmore » of physics are involved during the compression molding process, including the epoxy resin curing and the complex mechanical behavior of woven fabric structure. In the present study, the FE simulation of the compression molding process of resin based woven fabric composites at continuum level is conducted, which is enabled by the implementation of an integrated material modeling methodology in LS-Dyna. Specifically, the chemo-thermo-mechanical problem of compression molding is solved through the coupling of three material models, i.e., one thermal model for temperature history in the resin, one mechanical model to update the curing-dependent properties of the resin and another mechanical model to simulate the behavior of the woven fabric composites. Preliminary simulations of the carbon fiber/epoxy woven fabric composites in LS-Dyna are presented as a demonstration, while validations and models with real part geometry are planned in the future work.« less

Experimental and Numerical Simulation Analysis of Typical Carbon Woven Fabric/Epoxy Laminates Subjected to Lightning Strike

NASA Astrophysics Data System (ADS)

Yin, J. J.; Chang, F.; Li, S. L.; Yao, X. L.; Sun, J. R.; Xiao, Y.

2017-12-01

To clarify the evolution of damage for typical carbon woven fabric/epoxy laminates exposed to lightning strike, artificial lightning testing on carbon woven fabric/epoxy laminates were conducted, damage was assessed using visual inspection and damage peeling approaches. Relationships between damage size and action integral were also elucidated. Results showed that damage appearance of carbon woven fabric/epoxy laminate presents circular distribution, and center of the circle located at the lightning attachment point approximately, there exist no damage projected area dislocations for different layers, visual damage territory represents maximum damage scope; visible damage can be categorized into five modes: resin ablation, fiber fracture and sublimation, delamination, ablation scallops and block-shaped ply-lift; delamination damage due to resin pyrolysis and internal pressure exist obvious distinguish; project area of total damage is linear with action integral for the same type specimens, that of resin ablation damage is linear with action integral, but no correlation with specimen type, for all specimens, damage depth is linear with logarithm of action integral. The coupled thermal-electrical model constructed is capable to simulate the ablation damage for carbon woven fabric/epoxy laminates exposed to simulated lightning current through experimental verification.

Analysis of mechanical properties anisotropy of nanomodified carbon fibre-reinforced woven composites

NASA Astrophysics Data System (ADS)

Ruslantsev, A. N.; Portnova, Ya M.; Tairova, L. P.; Dumansky, A. M.

2016-10-01

The polymer binder cracking problem arises while designing and maintaining polymer composite-based aircraft load-bearing members. Some technological methods are used to solve this problem. In particular the injection of nanoagents can block the initiation and growth of microscopic cracks. Crack propagation can also be blocked if the strain energy release is not related with fracturing. One of the possible ways for such energy release is creep. Testing of the anisotropy of the woven carbon fibre reinforced plastic elastic characteristics and creep have been conducted. The samples with different layouts have been made of woven carbon fibre laminate BMI-3/3692 with nanomodified bismaleimide matrix. This matrix has a higher glass transition temperature and improved mechanical properties. The deformation regularities have been analyzed, layer elastic characteristics have been determined. The constitutive equations describing composite material creep have been obtained and its parameters have been defined. Experimental and calculated creep curves have been plotted. It was found that the effects of rheology arise as the direction of load does not match the direction of reinforcing fibres of the material.

Improved Strength and Toughness of Carbon Woven Fabric Composites with Functionalized MWCNTs

PubMed Central

Soliman, Eslam; Kandil, Usama; Reda Taha, Mahmoud

2014-01-01

This investigation examines the role of carboxyl functionalized multi-walled carbon nanotubes (COOH-MWCNTs) in the on- and off-axis flexure and the shear responses of thin carbon woven fabric composite plates. The chemically functionalized COOH-MWCNTs were used to fabricate epoxy nanocomposites and, subsequently, carbon woven fabric plates to be tested on flexure and shear. In addition to the neat epoxy, three loadings of COOH-MWCNTs were examined: 0.5 wt%, 1.0 wt% and 1.5 wt% of epoxy. While no significant statistical difference in the flexure response of the on-axis specimens was observed, significant increases in the flexure strength, modulus and toughness of the off-axis specimens were observed. The average increase in flexure strength and flexure modulus with the addition of 1.5 wt% COOH-MWCNTs improved by 28% and 19%, respectively. Finite element modeling is used to demonstrate fiber domination in on-axis flexure behavior and matrix domination in off-axis flexure behavior. Furthermore, the 1.5 wt% COOH-MWCNTs increased the toughness of carbon woven composites tested on shear by 33%. Microstructural investigation using Fourier Transform Infrared Spectroscopy (FTIR) proves the existence of chemical bonds between the COOH-MWCNTs and the epoxy matrix. PMID:28788698

Analysis of woven and braided fabric reinforced composites

NASA Technical Reports Server (NTRS)

Naik, Rajiv A.

1994-01-01

A general purpose micromechanics analysis that discretely models the yarn architecture within the textile repeating unit cell, was developed to predict overall, three dimensional, thermal and mechanical properties. This analytical technique was implemented in a user-friendly, personal computer-based, windows compatible code called Textile Composite Analysis for Design (TEXCAD). TEXCAD was used to analyze plain, 5-harness satin, and 8-harness satin weave composites along with 2-D braided and 2x2, 2-D triaxial braided composites. The calculated overall stiffnesses correlated well with available 3-D finite element results and test data for both the woven and the braided composites. Parametric studies were performed to investigate the effects of yarn size on the yarn crimp and the overall thermal and mechanical constants for plain weave composites. The effects of braid angle were investigated for the 2-D braided composites. Finally, the effects of fiber volume fraction on the yarn undulations and the thermal and mechanical properties of 2x2, 2-D triaxial braided composites were also investigated.

Fabrication and characterization of nanoclay modified PMR type polyimide composites reinforced with 3D woven basalt fabric

NASA Astrophysics Data System (ADS)

Xie, Jianfei; Qiu, Yiping

2009-07-01

Nanoclay modified PMR type polyimide composites were prepared from 3D orthogonal woven basalt fiber performs and nanoclay modified polyimide matrix resin, which derived from methylene dianiline (MDA), dimethyl ester of 3,3',4,4'- oxydiphthalic acid (ODPE), monomethyl ester of cis-5-norbornene-endo-2,3-dicarboxylic acid (NE) and nanoclay. The Na+-montmorillonite was organically treated using a 1:1 molar ratio mixture of dodecylamine (C12) and MDA. The rheological properties of neat B-stage PMR polyimide and 2% clay modified B-stage PMR polyimide were investigated. Based on the results obtained from the rheological tests, a two step compression molding process can be established for the composites. In the first step, the 3D fabric preforms were impregnated with polyimide resin in a vacuum oven and heated up for degassing the volatiles and by-products. In the second step, composites were compressed. The internal structure of the composites was observed by a microscope. Incorporation of 2% clay showed an improvement in the Tg and stiffness of the PMR polyimide. The resulting composites exhibited high thermal stability and good mechanical properties.

3D-WOVEN FIBER-REINFORCED COMPOSITE FOR CAD/CAM DENTAL APPLICATION

PubMed Central

Petersen, Richard; Liu, Perng-Ru

2016-01-01

Three-dimensional (3D)-woven noncrimp fiber-reinforced composite (FRC) was tested for mechanical properties in the two principal directions of the main XY plane and compared to different Computer-Aided-Design/Computer-Aided-Machining (CAD/CAM) Dental Materials. The Dental Materials included ceramic with Vitablock Mark II®, ProCAD®, InCeram® Spinel, InCeram® Alumina and InCeram® Zirconia in addition to a resin-based 3M Corp. Paradigm® particulate-filled composite. Alternate material controls included Coors 300 Alumina Ceramic and a tungsten carbide 22% cobalt cermet. The 3D-woven FRC was vacuum assisted resin transfer molding processed as a one-depth-thickness ~19-mm preform with a vinyl-ester resin and cut into blocks similar to the commercial CAD/CAM Dental Materials. Mechanical test samples prepared for a flexural three-point span length of 10.0 mm were sectioned for minimum-depth cuts to compare machinability and fracture resistance between groups. 3D-woven FRC improved mechanical properties with significant statistical differences over all CAD/CAM Dental Materials and Coors Alumina Ceramic for flexural strength (p<0.001), resilience (p<0.05), work of fracture (p<0.001), strain energy release (p<0.05), critical stress intensity factor (p<0.001) and strain (p<0.001). PMID:27642198

3D-WOVEN FIBER-REINFORCED COMPOSITE FOR CAD/CAM DENTAL APPLICATION.

PubMed

Petersen, Richard; Liu, Perng-Ru

2016-05-01

Three-dimensional (3D)-woven noncrimp fiber-reinforced composite (FRC) was tested for mechanical properties in the two principal directions of the main XY plane and compared to different Computer-Aided-Design/Computer-Aided-Machining (CAD/CAM) Dental Materials. The Dental Materials included ceramic with Vitablock Mark II®, ProCAD®, InCeram® Spinel, InCeram® Alumina and InCeram® Zirconia in addition to a resin-based 3M Corp. Paradigm® particulate-filled composite. Alternate material controls included Coors 300 Alumina Ceramic and a tungsten carbide 22% cobalt cermet. The 3D-woven FRC was vacuum assisted resin transfer molding processed as a one-depth-thickness ~19-mm preform with a vinyl-ester resin and cut into blocks similar to the commercial CAD/CAM Dental Materials. Mechanical test samples prepared for a flexural three-point span length of 10.0 mm were sectioned for minimum-depth cuts to compare machinability and fracture resistance between groups. 3D-woven FRC improved mechanical properties with significant statistical differences over all CAD/CAM Dental Materials and Coors Alumina Ceramic for flexural strength (p<0.001), resilience (p<0.05), work of fracture (p<0.001), strain energy release (p<0.05), critical stress intensity factor (p<0.001) and strain (p<0.001).

40 CFR 410.40 - Applicability; description of the woven fabric finishing subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Applicability; description of the woven fabric finishing subcategory. 410.40 Section 410.40 Protection of Environment ENVIRONMENTAL PROTECTION... proofing, soil repellency application and a special finish application. ...

Bactericidal activities of woven cotton and nonwoven polypropylene fabrics coated with hydroxyapatite-binding silver/titanium dioxide ceramic nanocomposite “Earth-plus”

PubMed Central

Kasuga, Eriko; Kawakami, Yoshiyuki; Matsumoto, Takehisa; Hidaka, Eiko; Oana, Kozue; Ogiwara, Naoko; Yamaki, Dai; Sakurada, Tsukasa; Honda, Takayuki

2011-01-01

Background Bacteria from the hospital environment, including linens and curtains, are often responsible for hospital-associated infections. The aim of the present study was to evaluate the bactericidal effects of fabrics coated with the hydroxyapatite-binding silver/titanium dioxide ceramic nanocomposite “Earth-plus”. Methods Bactericidal activities of woven and nonwoven fabrics coated with Earth-plus were investigated by the time-kill curve method using nine bacterial strains, including three Staphylococcus aureus, three Escherichia coli, and three Pseudomonas aeruginosa strains. Results The numbers of viable S. aureus and E. coli cells on both fabrics coated with Earth-plus decreased to below 2 log10 colony-forming units/mL in six hours and reached the detection limit in 18 hours. Viable cell counts of P. aeruginosa on both fabrics coated with Earth-plus could not be detected after 3–6 hours. Viable cells on woven fabrics showed a more rapid decline than those on nonwoven fabrics. Bacterial cell counts of the nine strains on fabrics without Earth-plus failed to decrease even after 18 hours. Conclusion Woven cotton and nonwoven polypropylene fabrics were shown to have excellent antibacterial potential. The woven fabric was more bactericidal than the nonwoven fabric. PMID:21931489

Numerical Simulation with Experimental Validation of the Draping Behavior of Woven Fabrics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodgers, William; Pasupuleti, Praveen; Zhao, Selina

Woven fabric composites are extensively used in molding complex geometrical shapes due to their high conformability compared to other fabrics. Preforming is an important step in the overall process. In this step, the two-dimensional fabric is draped to become the three-dimensional shape of the part prior to resin injection. During preforming, the orientation of the tows may change significantly compared to the initial orientations. Accurate prediction of the tow orientations after molding is important for evaluating the structural performance of the final part. This paper investigates the fiber angle changes for carbon fiber woven fabrics during draping over a truncatedmore » pyramid tool designed and fabricated at the General Motors Research Labs. This aspect of study is a subset of the broad study conducted under the purview of a Department of Energy project funded to GM in developing state of the art computational tools for integrated manufacturing and structural performance prediction of carbon fiber composites. Fabric bending, picture frame testing, and bias-extension evaluations were carried out to determine the material parameters for these fabrics. The PAM-FORM computer program was used to model the draping behavior of these fabrics. Following deformation, fiber angle changes at different locations on the truncated pyramid were measured experimentally. The predicted angles matched the experimental results well as measured along the centerline and at several different locations on the deformed fabric. Details of the test methods used as well as the numerical results with various simulation parameters will be provided.« less

Numerical and experimental analyses of out-of-plane deformation of triaxial woven fabric

NASA Astrophysics Data System (ADS)

Zhou, Hongtao; Xiao, Xueliang; Qian, Kun; Zhang, Kun; Zhang, Diantang

2018-05-01

With three sets of yarns interwoven in plane for angle-interlock structure, triaxial woven fabric (TWF) is a unique and perfect construction material for products subjected to multi-directional loads, as compared to classic fabrics of orthogonal structure. Finite-element analysis (FEA) and experimental methods are applied to study the out-of-plane deformation (OPD) behaviors of TWF and plain woven fabric (PWF). Among this, the yarn cross section, path and woven structure are obtained using optical microscopy, the related parameters are input to finite element model (FEM) for simulating the OPD behavior. This paper presents a detailed analysis on out-of-plane deformation behavior of TWF and PWF by the finite element method and experiment. In consideration of the comparability, TWF and PWF are designed and prepared with the same yarns and areal density (g/m2). The deformation profile, maximum stress and maximum deflection of TWF and PWF are obtained by FEA and experiment. It has been found that the maximum deflection and maximum stress of TWF is smaller than that of PWF under the same uniform negative pressure, both FEA and experiment. Furthermore, the stress distribution of TWF is more evenly than that of PWF, indicating that TWF exhibited superior isotropy in comparison with PWF for one more directional set of yarns in undertaking the OPD.

Debonding characteristics of adhesively bonded woven Kevlar composites

NASA Technical Reports Server (NTRS)

Mall, S.; Johnson, W. S.

1988-01-01

The fatigue damage mechanism of an adhesively bonded joint between fabric reinforced composite adherends was investigated with cracked-lap-shear specimens. Two bonded systems were studied: fabric Kevlar 49/5208 epoxy adherends bonded together with either EC 3445 or FM-300 adhesive. For each bonded system, two specimen geometries were tested. In all specimens tested, fatigue damage occurred in the form of cyclic debonding; however, the woven Kevlar specimens gave significantly slower debond growth rates and higher fracture toughness than previously found in the nonwoven adherend specimens. The surfaces for the woven adherends were not smooth; rather, they had regular crests (high spots) and troughs (low spots) due to the weave pattern. Radiographs of the specimens and examination of their failure surfaces revealed that fiber bridging occurred between the crests of the two adherends in the debonded region. The observed improvements in debond growth resistance and static fracture toughness are attributed to this bridging.

Strain Sharing Assessment in Woven Fiber Reinforced Concrete Beams Using Fiber Bragg Grating Sensors.

PubMed

Montanini, Roberto; Recupero, Antonino; De Domenico, Fabrizio; Freni, Fabrizio

2016-09-22

Embedded fiber Bragg grating sensors have been extensively used worldwide for health monitoring of smart structures. In civil engineering, they provide a powerful method for monitoring the performance of composite reinforcements used for concrete structure rehabilitation and retrofitting. This paper discusses the problem of investigating the strain transfer mechanism in composite strengthened concrete beams subjected to three-point bending tests. Fiber Bragg grating sensors were embedded both in the concrete tensioned surface and in the woven fiber reinforcement. It has been shown that, if interface decoupling occurs, strain in the concrete can be up to 3.8 times higher than that developed in the reinforcement. A zero friction slipping model was developed which fitted very well the experimental data.

An investigation of density measurement method for yarn-dyed woven fabrics based on dual-side fusion technique

NASA Astrophysics Data System (ADS)

Zhang, Rui; Xin, Binjie

2016-08-01

Yarn density is always considered as the fundamental structural parameter used for the quality evaluation of woven fabrics. The conventional yarn density measurement method is based on one-side analysis. In this paper, a novel density measurement method is developed for yarn-dyed woven fabrics based on a dual-side fusion technique. Firstly, a lab-used dual-side imaging system is established to acquire both face-side and back-side images of woven fabric and the affine transform is used for the alignment and fusion of the dual-side images. Then, the color images of the woven fabrics are transferred from the RGB to the CIE-Lab color space, and the intensity information of the image extracted from the L component is used for texture fusion and analysis. Subsequently, three image fusion methods are developed and utilized to merge the dual-side images: the weighted average method, wavelet transform method and Laplacian pyramid blending method. The fusion efficacy of each method is evaluated by three evaluation indicators and the best of them is selected to do the reconstruction of the complete fabric texture. Finally, the yarn density of the fused image is measured based on the fast Fourier transform, and the yarn alignment image could be reconstructed using the inverse fast Fourier transform. Our experimental results show that the accuracy of density measurement by using the proposed method is close to 99.44% compared with the traditional method and the robustness of this new proposed method is better than that of conventional analysis methods.

Vacuum infusion method for woven carbon/Kevlar reinforced hybrid composite

NASA Astrophysics Data System (ADS)

Hashim, N.; Majid, D. L.; Uda, N.; Zahari, R.; Yidris, N.

2017-12-01

The vacuum assisted resin transfer moulding (VaRTM) or Vacuum Infusion (VI) is one of the fabrication methods used for composite materials. Compared to other methods, this process costs lower than using prepregs because it does not need to use the autoclave to cure. Moreover, composites fabricated using this VI method exhibit superior mechanical properties than those made through hand layup process. In this study, the VI method is used in fabricating woven carbon/Kevlar fibre cloth with epoxy matrix. This paper reports the detailed methods on fabricating the hybrid composite using VI process and several precautions that need to be taken to avoid any damage to the properties of the composite material. The result highlights that the successfully fabricated composite has approximately 60% of fibres weight fraction. Since the composites produced by the VI process have a higher fibre percentage, this process should be considered for composites used in applications that are susceptible to the conditions where the fibres need to be the dominant element such as in tension loading.

Use of woven glass fibres to reinforce a composite veneer. A fracture resistance and acoustic emission study.

PubMed

Vallittu, P K

2002-05-01

The aim of this study was to investigate the possibility to reinforce the mechanically interlocked veneer of a porcelain-fused-to-metal (PFM) crown by woven glass fibre. A simulated situation to repair a fractured porcelain veneer was used in the experimental test set-up. A brass jig made into the shape of a framework of PFM maxillary central incisor crown with a retentive area at the palatal side of the incisal edge was used. A veneer were made with a restorative hybrid composite on the brass jig (control group). In the test groups, one or two layers of woven polymer pre-impregnated glass fibres (thickness: 0.06 mm/layer) were used by pressing the fibre weaves to the surface of the brass jig. Restorative hybrid composite was applied on the glass fibre weaves. Five veneers were made for all groups and the veneers were not cemented on the test jig. The veneers were loaded from the incisal edge until fracture occurred. The force was measured simultaneously with an acoustic emission analysis (AE) of the fracture propagation. Fracture force values for control veneers were 121 N and for those reinforced with one layer of glass fibres 399 N and for those reinforced with two layers of glass fibres 744 N ANOVA revealed significant difference between the mean values (P=0.003). The AE analysis showed different fracture propagation for the unreinforced and glass fibre reinforced veneers. The results of this study suggests that by placing two layers of woven glass fibres on the retentively shaped metal framework of the PFM crown before applying the restorative composite, considerably higher fracture resistance for the veneer could be obtained.

Strain Sharing Assessment in Woven Fiber Reinforced Concrete Beams Using Fiber Bragg Grating Sensors

PubMed Central

Montanini, Roberto; Recupero, Antonino; De Domenico, Fabrizio; Freni, Fabrizio

2016-01-01

Embedded fiber Bragg grating sensors have been extensively used worldwide for health monitoring of smart structures. In civil engineering, they provide a powerful method for monitoring the performance of composite reinforcements used for concrete structure rehabilitation and retrofitting. This paper discusses the problem of investigating the strain transfer mechanism in composite strengthened concrete beams subjected to three-point bending tests. Fiber Bragg grating sensors were embedded both in the concrete tensioned surface and in the woven fiber reinforcement. It has been shown that, if interface decoupling occurs, strain in the concrete can be up to 3.8 times higher than that developed in the reinforcement. A zero friction slipping model was developed which fitted very well the experimental data. PMID:27669251

Antibacterial properties of modified biodegradable PHB non-woven fabric.

PubMed

Slepička, P; Malá, Z; Rimpelová, S; Švorčík, V

2016-08-01

The antibacterial properties of poly(hydroxybutyrate) (PHB) non-woven fabric were explored in this study. The PHB was activated by plasma modification and subsequently processed with either immersion into a solution of nanoparticles or direct metallization. The wettability and surface chemistry of the PHB surface was determined. The thickness of the sputtered nanolayer on PHB fabric was characterized. It was found that plasma modification led to a formation of strongly hydrophilic surface, while the subsequent metallization by silver or gold resulted in a significantly increased water contact angle. Further, it was found that antibacterial activity may be controlled by the type of a metal and deposition method used. The immersion of plasma modified fabric into Ag nanoparticle solution led to enhanced antibacterial efficiency of PHB against Escherichia coli (E. coli). Direct silver sputtering on PHB fabric was proved to be a simple method for construction of a surface with strong antibacterial potency against both Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epidermidis). We demonstrated the antibacterial activity of PHB fabric modified by plasma activation and consecutive selection of a treatment method for an effective antibacterial surface construction. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of 3D woven cellular structures for adaptive composites based on thermoplastic hybrid yarns

NASA Astrophysics Data System (ADS)

Sennewald, C.; Vorhof, M.; Schegner, P.; Hoffmann, G.; Cherif, C.; Boblenz, J.; Sinapius, M.; Hühne, C.

2018-05-01

Flexible cellular 3D structures with structure-inherent compliance made of fiber-reinforced composites have repeatedly aroused the interest of international research groups. Such structures offer the possibility to meet the increasing demand for flexible and adaptive structures. The aim of this paper is the development of cellular 3D structures based on weaving technology. Considering the desired geometry of the 3D structure, algorithms are developed for the formation of geometry through tissue sub-areas. Subsequently, these sub-areas are unwound into the weaving level and appropriate weave patterns are developed. A particular challenge is the realization of compliant mechanisms in the woven fabric. This can be achieved either by combining different materials or, in particular, by implementing large stiffness gradients by means of varying the woven fabrics thickness, whereas differences in wall thickness have to be realized with a factor of 1:10. A manufacturing technology based on the weaving process is developed for the realization of the developed 3D cellular structures. To this end, solutions for the processing of hybrid thermoplastic materials (e.g. tapes), solutions for the integration of inlays in the weaving process (thickening of partial areas), and solutions for tissue retraction, as well as for the fabric pull-off (linear pull-off system) are being developed. In this way, woven cellular 3D structures with woven outer layers and woven joint areas (compliance) can be realized in a single process step and are subsequently characterized.

Fabrication of Fe–Co Magnetostrictive Fiber Reinforced Plastic Composites and Their Sensor Performance Evaluation

PubMed Central

Katabira, Kenichi; Yoshida, Yu; Masuda, Atsuji; Watanabe, Akihito; Narita, Fumio

2018-01-01

The inverse magnetostrictive effect is an effective property for energy harvesting; the material needs to have large magnetostriction and ease of mass production. Fe–Co alloys being magnetostrictive materials have favorable characteristics which are high strength, ductility, and excellent workability, allowing easy fabrication of Fe–Co alloy fibers. In this study, we fabricated magnetostrictive polymer composites, in which Fe–Co fibers were woven into polyester fabric, and discussed their sensor performance. Compression and bending tests were carried out to measure the magnetic flux density change, and the effects of magnetization, bias magnetic field, and the location of the fibers on the performance were discussed. It was shown that magnetic flux density change due to compression and bending is related to the magnetization of the Fe–Co fiber and the bias magnetic field. The magnetic flux density change of Fe–Co fiber reinforced plastics was larger than that of the plastics with Terfenol-D particles. PMID:29522455

Air-Inflated Fabric Structures

DTIC Science & Technology

2006-11-05

environmental exposure to ultraviolet rays, moisture, fire, chemicals, etc. Coating such as urethane, PVC (polyvinyl chloride), neoprene, EPDM (ethylene...tests on rubber -coated, plain-woven fabrics and established that the initial shear response was dominated by the coating and with increased shearing...Farboodmanesh, S., Chen, J., Mead, J. L., White, K., "Effect of Construction on Mechanical Behavior of Fabric Reinforced Rubber ," Rubber Division

Bn and Si-Doped Bn Coatings on Woven Fabrics

NASA Technical Reports Server (NTRS)

Hurwitz, Frances I.; Scott, John M.; Wheeler, Donald R.; Chayka, Paul V.; Gray, Hugh R. (Technical Monitor)

2002-01-01

A computer controlled, pulsed chemical vapor infiltration (CVI) system has been developed to deposit BN from a liquid borazine (B3N3H6) source, as well as silicon doped BN coatings using borazine and a silicon source, into 2-D woven ceramic fabric preforms. The coating process was evaluated as a function of deposition temperature, pressure, and precursor flow rate. Coatings were characterized by field emission scanning electron microscopy, electron dispersive spectroscopy and Auger spectroscopy. By controlling the reactant feed ratios, Si incorporation could be controlled over the range of 6-24 atomic percent.

Modeling the Elastic Modulus of 2D Woven CVI SiC Composites

NASA Technical Reports Server (NTRS)

Morscher, Gregory N.

2006-01-01

The use of fiber, interphase, CVI SiC minicomposites as structural elements for 2D-woven SiC fiber reinforced chemically vapor infiltrated (CVI) SiC matrix composites is demonstrated to be a viable approach to model the elastic modulus of these composite systems when tensile loaded in an orthogonal direction. The 0deg (loading direction) and 90deg (perpendicular to loading direction) oriented minicomposites as well as the open porosity and excess SiC associated with CVI SiC composites were all modeled as parallel elements using simple Rule of Mixtures techniques. Excellent agreement for a variety of 2D woven Hi-Nicalon(TradeMark) fiber-reinforced and Sylramic-iBN reinforced CVI SiC matrix composites that differed in numbers of plies, constituent content, thickness, density, and number of woven tows in either direction (i.e, balanced weaves versus unbalanced weaves) was achieved. It was found that elastic modulus was not only dependent on constituent content, but also the degree to which 90deg minicomposites carried load. This depended on the degree of interaction between 90deg and 0deg minicomposites which was quantified to some extent by composite density. The relationships developed here for elastic modulus only necessitated the knowledge of the fractional contents of fiber, interphase and CVI SiC as well as the tow size and shape. It was concluded that such relationships are fairly robust for orthogonally loaded 2D woven CVI SiC composite system and can be implemented by ceramic matrix composite component modelers and designers for modeling the local stiffness in simple or complex parts fabricated with variable constituent contents.

Fatigue damage characterization of braided and woven fiber reinforced polymer matrix composites at room and elevated temperatures

NASA Astrophysics Data System (ADS)

Montesano, John

The use of polymer matrix composites (PMC) for manufacturing primary load-bearing structural components has significantly increased in many industrial applications. Specifically in the aerospace industry, PMCs are also being considered for elevated temperature applications. Current aerospace-grade composite components subjected to fatigue loading are over-designed due to insufficient understanding of the material failure processes, and due to the lack of available generic fatigue prediction models. A comprehensive literature survey reveals that there are few fatigue studies conducted on woven and braided fabric reinforced PMC materials, and even fewer at elevated temperatures. It is therefore the objective of this study to characterize and subsequently model the elevated temperature fatigue behaviour of a triaxial braided PMC, and to investigate the elevated temperature fatigue properties of two additional woven PMCs. An extensive experimental program is conducted using a unique test protocol on the braided and woven composites, which consists of static and fatigue testing at various test temperatures. The development of mechanically-induced damage is monitored using a combination of non-destructive techniques which included infrared thermography, fiber optic sensors and edge replication. The observed microscopic damage development is quantified and correlated to the exhibited macroscopic material behaviour at all test temperatures. The fiber-dominated PMC materials considered in this study did not exhibit notable time- or temperature-dependent static properties. However, fatigue tests reveal that the local damage development is in fact notably influenced by temperature. The elevated temperature environment increases the toughness of the thermosetting polymers, which results in consistently slower fatigue crack propagation rates for the respective composite materials. This has a direct impact on the stiffness degradation rate and the fatigue lives for the braided

Progress on BN and Doped-BN Coatings on Woven Fabrics

NASA Technical Reports Server (NTRS)

Hurwitz, Frances I.; Scott, John M.; Chayka, Paul V.

2001-01-01

A novel, multistep process for applying interface coatings to woven structures using a pulsed CVD process is being evaluated. Borazine (B3N3H6), a neat liquid, and several Si precursors are used in the process to produce BN and SiBN coatings on Hi- Nicalon fabrics and preforms. A three variable, two level, full factorial matrix is proposed to define the influence of processing parameters. Coating morphology, uniformity and chemistry are characterized by field emission scanning electron microscopy (FESEM), energy dispersive (EDS) and Auger spectroscopies.

Cellulase finishing of woven, cotton fabrics in jet and winch machines.

PubMed

Cortez, J M; Ellis, J; Bishop, D P

2001-08-23

Some authors have reported that as the applied agitation rate increases, the apparent activity of the endoglucanases from Trichoderma reesei towards cotton cellulose increases more markedly than does the apparent activity of the cellobiohydrolases. This suggests that the quality of cellulase finishing effects on cellulosic textiles may be machine-type dependent. The present work using total crude, endoglucanase-rich and cellobiohydrolase-rich cellulases from T. reesei confirmed that the final properties of woven, cotton fabrics treated under realistic processing conditions in a jet machine, were measurably and perceivably different from those of the same fabrics, treated using the same processing conditions of temperature, time, pH, enzyme concentration and fabric to liquor ratio, but in a winch machine. The results are interpreted in terms of the effects of agitation rate on the adsorption-desorption behaviour of the T. reesei endoglucanases and cellobiohydrolases.

Investigation and modeling of the elastic-plastic fracture behavior of continuous woven fabric-reinforced ceramic composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kahl, W.K.

1997-03-01

The paper describes a study which attempted to extrapolate meaningful elastic-plastic fracture toughness data from flexure tests of a chemical vapor-infiltrated SiC/Nicalon fiber-reinforced ceramic matrix composite. Fibers in the fabricated composites were pre-coated with pyrolytic carbon to varying thicknesses. In the tests, crack length was not measured and the study employed an estimate procedure, previously used successfully for ductile metals, to derive J-R curve information. Results are presented in normalized load vs. normalized displacements and comparative J{sub Ic} behavior as a function of fiber precoating thickness.

Comparative Analysis of Soft Computing Models in Prediction of Bending Rigidity of Cotton Woven Fabrics

NASA Astrophysics Data System (ADS)

Guruprasad, R.; Behera, B. K.

2015-10-01

Quantitative prediction of fabric mechanical properties is an essential requirement for design engineering of textile and apparel products. In this work, the possibility of prediction of bending rigidity of cotton woven fabrics has been explored with the application of Artificial Neural Network (ANN) and two hybrid methodologies, namely Neuro-genetic modeling and Adaptive Neuro-Fuzzy Inference System (ANFIS) modeling. For this purpose, a set of cotton woven grey fabrics was desized, scoured and relaxed. The fabrics were then conditioned and tested for bending properties. With the database thus created, a neural network model was first developed using back propagation as the learning algorithm. The second model was developed by applying a hybrid learning strategy, in which genetic algorithm was first used as a learning algorithm to optimize the number of neurons and connection weights of the neural network. The Genetic algorithm optimized network structure was further allowed to learn using back propagation algorithm. In the third model, an ANFIS modeling approach was attempted to map the input-output data. The prediction performances of the models were compared and a sensitivity analysis was reported. The results show that the prediction by neuro-genetic and ANFIS models were better in comparison with that of back propagation neural network model.

An efficient nontraditional method of directly converting a cotton fibrous material into a woven-like hydroentangled nonwoven cotton fabric

USDA-ARS?s Scientific Manuscript database

The traditional technology of producing cotton woven fabrics is comprised of about 20 mechanical and chemical processes that generally are costly, slow, inefficient, and environmentally somewhat unfriendly. A modern system, using fewer preparatory processes, of fabricating hydro-entangled cotton and...

Non-woven PET fabric reinforced and enhanced the performance of ultrafiltration membranes composed of PVDF blended with PVDF-g-PEGMA for industrial applications

NASA Astrophysics Data System (ADS)

Wang, Shuai; Li, Tong; Chen, Chen; Chen, Sheng; Liu, Baicang; Crittenden, John

2018-03-01

Ultrafiltration (UF) membranes composed of poly(vinylidene fluoride) (PVDF) blended with poly(vinylidene fluoride)-graft-poly(ethylene glycol) methyl ether methacrylate (PVDF-g-PEGMA) can present high flux and excellent foulant removal efficiencies under suitable preparation conditions. However, these PVDF/PVDF-g-PEGMA blended membranes cannot be applied industrially because of the insufficient mechanical strength (strength-to-break value of 8.4 ± 0.6 MPa). We incorporated two types of non-woven polyethylene terephthalate (PET) fabrics (thin hydrophobic and thick hydrophilic fabrics) as support layers to improve the mechanical properties of the blended membranes. The thin and thick PET fabrics were able to significantly improve the tensile strength to 23.3 ± 3.7 MPa and 30.1 ± 1.4 MPa, respectively. The PET fabrics had a limited impact on the separation-related membrane performance such as hydrophilicity, foulant rejection, whereas the mechanical strength and pure water flux was improved several folds. The enhanced flux was attributed to the higher surface porosity and wider finger-like voids in the cross-section. The thin PET fabric with larger porosity was able to maintain a consistent toughness simultaneously; thus it is recommended as a support material for this blended membrane.

Living nano-micro fibrous woven fabric/hydrogel composite scaffolds for heart valve engineering.

PubMed

Wu, Shaohua; Duan, Bin; Qin, Xiaohong; Butcher, Jonathan T

2017-03-15

Regeneration and repair of injured or diseased heart valves remains a clinical challenge. Tissue engineering provides a promising treatment approach to facilitate living heart valve repair and regeneration. Three-dimensional (3D) biomimetic scaffolds that possess heterogeneous and anisotropic features that approximate those of native heart valve tissue are beneficial to the successful in vitro development of tissue engineered heart valves (TEHV). Here we report the development and characterization of a novel composite scaffold consisting of nano- and micro-scale fibrous woven fabrics and 3D hydrogels by using textile techniques combined with bioactive hydrogel formation. Embedded nano-micro fibrous scaffolds within hydrogel enhanced mechanical strength and physical structural anisotropy of the composite scaffold (similar to native aortic valve leaflets) and also reduced its compaction. We determined that the composite scaffolds supported the growth of human aortic valve interstitial cells (HAVIC), balanced the remodeling of heart valve ECM against shrinkage, and maintained better physiological fibroblastic phenotype in both normal and diseased HAVIC over single materials. These fabricated composite scaffolds enable the engineering of a living heart valve graft with improved anisotropic structure and tissue biomechanics important for maintaining valve cell phenotypes. Heart valve-related disease is an important clinical problem, with over 300,000 surgical repairs performed annually. Tissue engineering offers a promising strategy for heart valve repair and regeneration. In this study, we developed and tissue engineered living nano-micro fibrous woven fabric/hydrogel composite scaffolds by using textile technique combined with bioactive hydrogel formation. The novelty of our technique is that the composite scaffolds can mimic physical structure anisotropy and the mechanical strength of natural aortic valve leaflet. Moreover, the composite scaffolds prevented the

Effects of Crimped Fiber Paths on Mixed Mode Delamination Behaviors in Woven Fabric Composites

DTIC Science & Technology

2016-09-01

continuum finite - element models. Three variations of a plain-woven fabric architecture—each of which had different crimped fiber paths—were considered... Finite - Element Analysis Fracture Mechanics Fracture Toughness Mixed Modes Strain Energy Release Rate 16. SECURITY...polymer FB Fully balanced laminate FEA Finite - element analysis FTCM Fracture toughness conversion mechanism G Shear modulus GI, GII, GIII Mode

Study of Wrinkle Resistant, Breathable, Anti-Uv Nanocoated Woven Polyester Fabric

NASA Astrophysics Data System (ADS)

Memon, Hafeezullah; Yasin, Sohail; Khoso, Nazakat Ali; Memon, Samiulah

2016-02-01

The multifunctional textiles are interesting areas to be researched on. In this paper, the effect of the fiber nanocoating on the wrinkle recovery, air permeability and anti-Ultraviolet (UV) property of different woven fabrics using sol-gel method has been studied. The sol-gel method has various advantages over other methods. Along with these properties, no change in visual appearance has also been discussed in this paper. The dispersion of nanoparticles of titanium was obtained into silica sol. The characterization of nanocoating was done using Field emission scanning electron micrograph (FESEM) and Fourier transform infrared spectroscopy (FTIR) studies. The fabric wrinkle recovery properties, air permeability and anti-UV performance were analyzed using three different immersion timings into the nanosol. The results revealed that both wrinkle recovery properties and anti-UV performance have increased with respect to immersing time of the nanocoating although a slight decrease in air permeability and whiteness index of the fabric was also observed.

Wearable woven supercapacitor fabrics with high energy density and load-bearing capability.

PubMed

Shen, Caiwei; Xie, Yingxi; Zhu, Bingquan; Sanghadasa, Mohan; Tang, Yong; Lin, Liwei

2017-10-30

Flexible power sources with load bearing capability are attractive for modern wearable electronics. Here, free-standing supercapacitor fabrics that can store high electrical energy and sustain large mechanical loads are directly woven to be compatible with flexible systems. The prototype with reduced package weight/volume provides an impressive energy density of 2.58 mWh g -1 or 3.6 mWh cm -3 , high tensile strength of over 1000 MPa, and bearable pressure of over 100 MPa. The nanoporous thread electrodes are prepared by the activation of commercial carbon fibers to have three-orders of magnitude increase in the specific surface area and 86% retention of the original strength. The novel device configuration woven by solid electrolyte-coated threads shows excellent flexibility and stability during repeated mechanical bending tests. A supercapacitor watchstrap is used to power a liquid crystal display as an example of load-bearing power sources with various form-factor designs for wearable electronics.

Sonophotocatalytic degradation of dye C.I. Acid Orange 7 by TiO2 and Ag nanoparticles immobilized on corona pretreated polypropylene non-woven fabric.

PubMed

Marković, Darka; Šaponjić, Zoran; Radoičić, Marija; Radetić, Tamara; Vodnik, Vesna; Potkonjak, Branislav; Radetić, Maja

2015-05-01

This study discusses the possibility of using corona pre-treated polypropylene (PP) non-woven fabric as a support for immobilization of colloidal TiO2 and Ag nanoparticles in order to remove dye C.I. Acid Orange 7 from aqueous solution. Dye removal efficiency by sonocatalysis, photocatalysis and sonophotocatalysis was evaluated on corona pre-treated fabric loaded with TiO2 nanoparticles, corona pre-treated fabric double loaded with TiO2 nanoparticles and corona pre-treated fabrics loaded with TiO2 nanoparticles before and after deposition of Ag nanoparticles. In addition, the stability of PP non-woven fabric during these processes was investigated. The substrates were characterized by SEM, EDX and AAS analyses. The change of the dye concentration was evaluated by UV-VIS spectrophotometry. Unlike sonocatalysis and photocatalysis, complete dye removal from both solution and non-woven fabric was obtained already after 240-270 min of sonophotocatalysis. Corona pre-treated PP non-woven fabric loaded with Ag nanoparticles prior to deposition of TiO2 nanoparticles provided excellent degradation efficiency and superior reusability. Sonophotocatalytic degradation of dye in the presence of all investigated samples was the most prominent in acidic conditions. Although this nanocomposite system ensured fast discoloration of dye solution, TOC values of water measured after sonophotocatalysis were not satisfactory because of PP degradation. Therefore, it is suggested to include TOC evaluation in each case study where different supports for TiO2 nanoparticles are used since these nanoparticles may guarantee the dye removal from solution but the stability of support could be problematic causing even more serious environmental impact. Copyright © 2014 Elsevier B.V. All rights reserved.

Modeling of chemical vapor infiltration for ceramic composites reinforced with layered, woven fabrics

NASA Technical Reports Server (NTRS)

Chung, Gui-Yung; Mccoy, Benjamin J.

1991-01-01

A homogeneous model is developed for the chemical vapor infiltration by one-dimensional diffusion into a system of layered plies consisting of woven tows containing bundles of filaments. The model predictions of the amount of deposition and the porosity of the sample as a function of time are compared with the predictions of a recent nonhomogeneous model with aligned holes formed by the weave. The nonhomogeneous model allows for diffusion through the aligned holes, into the spaces between plies, and into the gaps around filaments; i.e., three diffusion equations apply. Relative to the nonhomogeneous results, the homogeneous model underestimates the amount of deposition, since the absence of holes and spaces allows earlier occlusion of gaps around filaments and restricts the vapor infiltration.

Study for fabrication, evaluation, and testing of monolayer woven type materials for space suit insulation

NASA Technical Reports Server (NTRS)

Merrick, E. B.

1979-01-01

An alternative space suit insulation concept using a monolayer woven pile material is discussed. The material reduces cost and improves the durability of the overgarment, while providing protection similar to that provided by multilayer insulation (MLI). Twelve samples of different configurations were fabricated and tested for compressibility and thermal conductivity as a function of compression loading. Two samples which showed good results in the initial tests were further tested for thermal conductivity with respect to ambient pressure and temperature. Results of these tests were similar to results of the MLI tests, indicating the potential of the monolayer fabric to replace the present MLI. A seaming study illustrated that the fabric can be sewn in a structurally sound seam with minimal heat loss. It is recommended that a prototype thermal meteroid garment be fabricated.

Creation of Woven Structures Impacting Self-cleaning Superoleophobicity

NASA Astrophysics Data System (ADS)

Lim, Jihye

For protection of human life from harmful or toxic liquids in working areas, solid surface resistance to liquid with low surface tension (e.g. oil) should be achieved in the outermost layer of protective clothing. Based on the literature review, multiscale structures were emphasized because they can increase roughness on a solid surface and create more void spaces of different sizes. The roughness and void spaces contribute to creating a liquid-vapor interface and reducing the liquid contact area to the solid surface. Woven fabric inherently consists of multiscale structures by its construction: microscale in a yarn structure and macroscale in a fabric structure. When the solid surface tension is low relative to oil, creating an appropriate structural geometry will become a critical way to obtain a superoleophobic surface for oil-resistance. Theoretical modeling and experiments with actual fabric samples were utilized to predict and prove the highest performing structural geometry in woven fabric, respectively. The theoretical geometric modeling accounted for the different weave structures, the yarn compression by the yarn flattening factor, e, and the void space by the void space ratio to the fiber or yarn diameter, T, impacting the liquid apparent contact angle on a fabric surface. The Cassie-Baxter equations were developed using Young's contact angle, thetae, thetae and e, or thetae, e, and T, to predict the liquid apparent contact angle for different geometries. In addition, to prevent a liquid's penetration into a solid structure, the ranges of the protuberance height (>> h2) and distance (< 4ℓ 2 cap) were predicted by the definition of the Laplace pressure, the capillary pressure, and the sagging phenomenon. Those predictions were in strong agreement with the results from the empirical experiment using the actual woven fabric samples. This study identified the impact of the geometries in yarn and woven fabric structures on the fabric resistance against oil

Investigation of Woven Characteristics on Electromagnetic Shielding Behaviour

NASA Astrophysics Data System (ADS)

Javadi Toghchi, M.; Loghin, C.; Cristian, I.; Campagne, C.; Bruniaux, P.; Cayla, A.

2018-06-01

Textiles have been highly applied for electromagnetic shielding purposes due to the increasing concern about health issues caused by human exposure to radiation. Properties of conductive yarn, fabric structure, and garment design have extreme effects on the electromagnetic behaviour and comfort of the final product. Lots of electromagnetic shielding textiles are made of metallic yarns regarding their high electrical conductivity. Therefore, some researchers have worked on electromagnetic shielding textiles made of metals. For example; the shielding effectiveness of woven fabrics made of hybrid yarns containing stainless steel wire was investigated. As discussed earlier, the fabric structure has significant effects on electromagnetic protection. Consequently, woven samples were produced using two different commercial electroconductive yarns (PA12 coated with Ag and Inox) to investigate the effects of the fabric structure. The main purpose was to define the best pattern among three basic woven patterns leads to the highest electromagnetic shielding. Moreover, the different weft yarn densities were applied to examine the effects of yarn density on the level of electromagnetic shielding. The electromagnetic shielding effectiveness of all the 2-layer samples was evaluated in the frequency range from 0.8 to10 GHz in an anechoic chamber. The woven sample with higher yarn density of PA12 coated with Ag yarns shows higher protection against radiation. To conclude, the results show that the yarn properties play the main role in shielding as well as yarn density and fabric pattern.

Optimization of woven jute/glass fibre-reinforced polyester hybrid composite solar parabolic trough collector

NASA Astrophysics Data System (ADS)

Reddy, K. S.; Singla, Hitesh

2017-07-01

In the present work, structural analysis of 5.77m × 4m woven jute (J)/glass (G) fibre-reinforced polyester hybrid composite solar parabolic trough is carried out based on trough parameters to obtain the minimum RMS local slope deviation, termed as SDx value under gravity loading. The optimization is done by varying parameters viz. direction and size of reinforced conduits, stacking number and sequence of hybrid trough laminate at fibre orientation of Δθ=45° and Δθ=60° amongst the layers at 0° collector angle. The analysis revealed that the configuration in which the conduits are placed in both X and Y directions is preferred over other configurations to scale down the effect of wind loads. Furthermore it has been observed that laminate of the order [0°G/45°G/-45°J/90°J]s undergoes minimum surface deformation amongst all the other configurations at conduit reinforcement in both X and Y directions for a conduit thickness of 0.75 mm and radius of 10 mm and obtains the overall SDx value of 1.3492 mrad. The results shows that proposed trough model is very promising and evolves a cost effective system.

Preparation of a non-woven poly(ε-caprolactone) fabric with partially embedded apatite surface for bone tissue engineering applications by partial surface melting of poly(ε-caprolactone) fibers.

PubMed

Kim, In Ae; Rhee, Sang-Hoon

2017-07-01

This article describes a novel method for the preparation of a biodegradable non-woven poly(ε-caprolactone) fabric with a partially embedded apatite surface designed for application as a scaffold material for bone tissue engineering. The non-woven poly(ε-caprolactone) fabric was generated by the electro-spinning technique and then apatite was coated in simulated body fluid after coating the PVA solution containing CaCl 2 ·2H 2 O. The apatite crystals were partially embedded or fully embedded into the thermoplastic poly(ε-caprolactone) fibers by controlling the degree of poly(ε-caprolactone) fiber surface melting in a convection oven. Identical apatite-coated poly(ε-caprolactone) fabric that did not undergo heat-treatment was used as a control. The features of the embedded apatite crystals were evaluated by FE-SEM, AFM, EDS, and XRD. The adhesion strengths of the coated apatite layers and the tensile strengths of the apatite coated fabrics with and without heat-treatment were assessed by the tape-test and a universal testing machine, respectively. The degree of water absorbance was assessed by adding a DMEM droplet onto the fabrics. Moreover, cell penetrability was assessed by seeding preosteoblastic MC3T3-E1 cells onto the fabrics and observing the degrees of cell penetration after 1 and 4 weeks by staining nuclei with DAPI. The non-woven poly(ε-caprolactone) fabric with a partially embedded apatite surface showed good water absorbance, cell penetrability, higher apatite adhesion strength, and higher tensile strength compared with the control fabric. These results show that the non-woven poly(ε-caprolactone) fabric with a partially embedded apatite surface is a potential candidate scaffold for bone tissue engineering due to its strong apatite adhesion strength and excellent cell penetrability. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1973-1983, 2017. © 2017 Wiley Periodicals, Inc.

Isotropy equilibrium of the double woven fabric with cotton face and wool reverse fibrous compositions

NASA Astrophysics Data System (ADS)

Rahnev, I.; Rimini, G.

2017-10-01

The equilibrium of the masses and the mechanical properties between the warp and the weft is a determining factor for the quality of the woven fabrics. When the fabric has a multi-layered structure and is designed for protective clothing, the uniform distribution of the elastical resistance acquires a paramount importance for the consumer properties. Isotropy in the sense of absolute equalising of the properties between the base and the weft evaluates the achieved optimum cohesion between the weaving threads and directs the weaving cycle settings. The possible variation of the ratio between the elastic modules of the warp and the weft, depending on the weft spacing and the warp tension, is the basic idea of this article.

Improved Mechanical Properties of Various Fabric-Reinforced Geocomposite at Elevated Temperature

NASA Astrophysics Data System (ADS)

Samal, Sneha; Phan Thanh, Nhan; Petríková, Iva; Marvalová, Bohadana

2015-07-01

This article signifies the improved performance of the various types of fabric reinforcement of geopolymer as a function of physical, thermal, mechanical, and heat-resistant properties at elevated temperatures. Geopolymer mixed with designed Si:Al ratios of 15.6 were synthesized using three different types of fabric reinforcement such as carbon, E-glass, and basalt fibers. Heat testing was conducted on 3-mm-thick panels with 15 × 90 mm surface exposure region. The strength of carbon-based geocomposite increased toward a higher temperature. The basalt-reinforced geocomposite strength decreased due to the catastrophic failure in matrix region. The poor bridging effect and dissolution of fabric was observed in the E-glass-reinforced geocomposite. At an elevated temperature, fiber bridging was observed in carbon fabric-reinforced geopolymer matrix. Among all the fabrics, carbon proved to be suitable candidate for the high-temperature applications in thermal barrier coatings and fire-resistant panels.

Effect of Mesoscale and Multiscale Modeling on the Performance of Kevlar Woven Fabric Subjected to Ballistic Impact: A Numerical Study

NASA Astrophysics Data System (ADS)

Jia, Xin; Huang, Zhengxiang; Zu, Xudong; Gu, Xiaohui; Xiao, Qiangqiang

2013-12-01

In this study, an optimal finite element model of Kevlar woven fabric that is more computational efficient compared with existing models was developed to simulate ballistic impact onto fabric. Kevlar woven fabric was modeled to yarn level architecture by using the hybrid elements analysis (HEA), which uses solid elements in modeling the yarns at the impact region and uses shell elements in modeling the yarns away from the impact region. Three HEA configurations were constructed, in which the solid element region was set as about one, two, and three times that of the projectile's diameter with impact velocities of 30 m/s (non-perforation case) and 200 m/s (perforation case) to determine the optimal ratio between the solid element region and the shell element region. To further reduce computational time and to maintain the necessary accuracy, three multiscale models were presented also. These multiscale models combine the local region with the yarn level architecture by using the HEA approach and the global region with homogenous level architecture. The effect of the varying ratios of the local and global area on the ballistic performance of fabric was discussed. The deformation and damage mechanisms of fabric were analyzed and compared among numerical models. Simulation results indicate that the multiscale model based on HEA accurately reproduces the baseline results and obviously decreases computational time.

Energy Absorption Capacity in Natural Fiber Reinforcement Composites Structures

PubMed Central

López-Alba, Elías; Díaz, Francisco

2018-01-01

The study of natural fiber reinforcement composite structures has focused the attention of the automobile industry due to the new regulation in relation to the recyclability and the reusability of the materials preserving and/or improving the mechanical characteristics. The influence of different parameters on the material behavior of natural fiber reinforced plastic structures has been investigated, showing the potential for transport application in energy absorbing structures. Two different woven fabrics (twill and hopsack) made of flax fibers as well as a non-woven mat made of a mixture of hemp and kenaf fibers were employed as reinforcing materials. These reinforcing textiles were impregnated with both HD-PE (high-density polyethylen) and PLA (polylactic acid) matrix, using a continuous compression molding press. The impregnated semi-finished laminates (so-called organic sheets) were thermoformed in a second step to half-tubes that were assembled through vibration-welding process to cylindric crash absorbers. The specimens were loaded by compression to determine the specific energy absorption capacity. Quasi-static test results were compared to dynamic test data obtained on a catapult arrangement. The differences on the specific energies absorption (SEA) as a function of different parameters, such as the wall thickness, the weave material type, the reinforced textiles, and the matrix used, depending on the velocity rate application were quantified. In the case of quasi-static analysis it is observed a 20% increment in the SEA value when wove Hopsack fabric reinforcement is employed. No velocity rate influence from the material was observed on the SEA evaluation at higher speeds used to perform the experiments. The influence of the weave configuration (Hopsack) seems to be more stable against buckling effects at low loading rates with 10% higher SEA values. An increase of SEA level of up to 72% for PLA matrix was observed when compared with HD-PE matrix. PMID

Energy Absorption Capacity in Natural Fiber Reinforcement Composites Structures.

PubMed

López-Alba, Elías; Schmeer, Sebastian; Díaz, Francisco

2018-03-13

The study of natural fiber reinforcement composite structures has focused the attention of the automobile industry due to the new regulation in relation to the recyclability and the reusability of the materials preserving and/or improving the mechanical characteristics. The influence of different parameters on the material behavior of natural fiber reinforced plastic structures has been investigated, showing the potential for transport application in energy absorbing structures. Two different woven fabrics (twill and hopsack) made of flax fibers as well as a non-woven mat made of a mixture of hemp and kenaf fibers were employed as reinforcing materials. These reinforcing textiles were impregnated with both HD-PE (high-density polyethylen) and PLA (polylactic acid) matrix, using a continuous compression molding press. The impregnated semi-finished laminates (so-called organic sheets) were thermoformed in a second step to half-tubes that were assembled through vibration-welding process to cylindric crash absorbers. The specimens were loaded by compression to determine the specific energy absorption capacity. Quasi-static test results were compared to dynamic test data obtained on a catapult arrangement. The differences on the specific energies absorption (SEA) as a function of different parameters, such as the wall thickness, the weave material type, the reinforced textiles, and the matrix used, depending on the velocity rate application were quantified. In the case of quasi-static analysis it is observed a 20% increment in the SEA value when wove Hopsack fabric reinforcement is employed. No velocity rate influence from the material was observed on the SEA evaluation at higher speeds used to perform the experiments. The influence of the weave configuration (Hopsack) seems to be more stable against buckling effects at low loading rates with 10% higher SEA values. An increase of SEA level of up to 72% for PLA matrix was observed when compared with HD-PE matrix.

Durability of self-healing woven glass fabric/epoxy composites

NASA Astrophysics Data System (ADS)

Yin, Tao; Rong, Min Zhi; Zhang, Ming Qiu; Zhao, Jian Qing

2009-07-01

In this work, the durability of the healing capability of self-healing woven glass fabric/epoxy laminates was investigated. The composites contained a two-component healing system with epoxy-loaded urea-formaldehyde microcapsules as the polymerizable binder and CuBr2(2-methylimidazole)4 (CuBr2(2-MeIm)4) as the latent hardener. It was found that the healing efficiency of the laminates firstly decreased with storage time at room temperature, and then leveled off for over two months. By means of a systematic investigation and particularly verification tests with dynamic mechanical analysis (DMA), diffusion of epoxy monomer from the microcapsules due to volumetric contraction of the composites during manufacturing was found to be the probable cause. The diffusing sites on the microcapsules were eventually blocked because the penetrated resin was gradually cured by the remnant amine curing agent in the composites' matrix, and eventually the healing ability was no longer reduced after a longer storage time. The results should help to develop approaches for improving the service stability of the laminates.

Stitch modeling of non crimp fabric in forming simulations

NASA Astrophysics Data System (ADS)

Steer, Q.; Colmars, J.; Boisse, P.

2018-05-01

The use of Non Crimp Fabric composite has increased during the last years due to cheaper cost of manufacturing and high mechanicals properties suitable for applications such as aeronautic, automotive and wind turbines. The main difference between Non Crimp Fabric (NCF) and textile reinforcement is the mean of manufacturing: where in textile fibers are woven, in NCF layers of unidirectional oriented fibers are assembled with a stitch. As a consequence, the stitch especially its geometry (stitch pattern) will have a major influence on the deformation of this type of reinforcement during forming process. Experimental campaigns on NCF samples compared to textile with the same fibers orientation have showed that the stitch affects the shear behavior of the reinforcement which is the main mode of deformation in the forming process. A description of the stitch has been implemented in a shell element for macro scale forming simulation as a first approach based on simple hypothesis. Further works are focus on the specific behavior of the stitch along the fabric and interaction with the fibers layers during shear deformation of the reinforcement and a method to implement the stitch in a more refined model of the fabric.

Fabrication of cast particle-reinforced metals via pressure infiltration

NASA Technical Reports Server (NTRS)

Klier, E. M.; Mortensen, A.; Cornie, J. A.; Flemings, M. C.

1991-01-01

A new casting process for fabrication of particle-reinforced metals is presented whereby a composite of particulate reinforcing phase in metal is first produced by pressure infiltration. This composite is then diluted in additional molten metal to obtain the desired reinforcement volume fraction and metal composition. This process produces a pore-free as-cast particulate metal-matrix composite. This process is demonstrated for fabrication of magnesium-matrix composites containing SiC reinforcements of average diameter 30, 10 and 3 microns. It is compared with the compocasting process, which was investigated as well for similar SiC particles in Mg-10 wt pct Al, and resulted in unacceptable levels of porosity in the as-cast composite.

Antimicrobial nano-silver non-woven polyethylene terephthalate fabric via an atmospheric pressure plasma deposition process

PubMed Central

Deng, Xiaolong; Yu Nikiforov, Anton; Coenye, Tom; Cools, Pieter; Aziz, Gaelle; Morent, Rino; De Geyter, Nathalie; Leys, Christophe

2015-01-01

An antimicrobial nano-silver non-woven polyethylene terephthalate (PET) fabric has been prepared in a three step process. The fabrics were first pretreated by depositing a layer of organosilicon thin film using an atmospheric pressure plasma system, then silver nano-particles (AgNPs) were incorporated into the fabrics by a dipping-dry process, and finally the nano-particles were covered by a second organosilicon layer of 10-50 nm, which acts as a barrier layer. Different surface characterization techniques like SEM and XPS have been implemented to study the morphology and the chemical composition of the nano-silver fabrics. Based on these techniques, a uniform immobilization of AgNPs in the PET matrix has been observed. The antimicrobial activity of the treated fabrics has also been tested using P. aeruginosa, S. aureus and C. albicans. It reveals that the thickness of the barrier layer has a strong effect on the bacterial reduction of the fabrics. The durability and stability of the AgNPs on the fabrics has also been investigated in a washing process. By doing so, it is confirmed that the barrier layer can effectively prevent the release of AgNPs and that the thickness of the barrier layer is an important parameter to control the silver ions release. PMID:25951432

Self-healing woven glass fabric/epoxy composites with the healant consisting of micro-encapsulated epoxy and latent curing agent

NASA Astrophysics Data System (ADS)

Yin, Tao; Zhou, Lin; Zhi Rong, Min; Qiu Zhang, Ming

2008-02-01

This paper reports a study of self-healing woven glass fabric reinforced epoxy composites. The healing agent was a two-component one synthesized in the authors' laboratory, which consisted of epoxy-loaded urea-formaldehyde microcapsules as the polymerizable binder and CuBr2(2-methylimidazole)4 (CuBr2(2-MeIm)4) as the latent hardener. Both the microcapsules and the matching catalyst were pre-embedded and pre-dissolved in the composites' matrix, respectively. When the microcapsules are split by propagating cracks, the uncured epoxy can be released into the damaged areas and then consolidated under the catalysis of CuBr2(2-MeIm)4 that was homogeneously distributed in the composites' matrix on a molecular scale. As a result, the cracked faces can be bonded together. The influence of the content of the self-healing agent on the composites' tensile properties, interlaminar fracture toughness and healing efficiency was evaluated. It was found that a healing efficiency over 70% relative to the fracture toughness of virgin composites was obtained in the case of 30 wt% epoxy-loaded microcapsules and 2 wt% latent hardener.

Woven electrochemical fabric-based test sensors (WEFTS): a new class of multiplexed electrochemical sensors.

PubMed

Choudhary, Tripurari; Rajamanickam, G P; Dendukuri, Dhananjaya

2015-05-07

We present textile weaving as a new technique for the manufacture of miniature electrochemical sensors with significant advantages over current fabrication techniques. Biocompatible silk yarn is used as the material for fabrication instead of plastics and ceramics used in commercial sensors. Silk yarns are coated with conducting inks and reagents before being handloom-woven as electrodes into patches of fabric to create arrays of sensors, which are then laminated, cut and packaged into individual sensors. Unlike the conventionally used screen-printing, which results in wastage of reagents, yarn coating uses only as much reagent and ink as required. Hydrophilic and hydrophobic yarns are used for patterning so that sample flow is restricted to a small area of the sensor. This simple fluidic control is achieved with readily available materials. We have fabricated and validated individual sensors for glucose and hemoglobin and a multiplexed sensor, which can detect both analytes. Chronoamperometry and differential pulse voltammetry (DPV) were used to detect glucose and hemoglobin, respectively. Industrial quantities of these sensors can be fabricated at distributed locations in the developing world using existing skills and manufacturing facilities. We believe such sensors could find applications in the emerging area of wearable sensors for chemical testing.

Evaluation of a non-woven fabric coated with a chitosan bi-layer composite for wound dressing.

PubMed

Liu, Bai-Shuan; Yao, Chun-Hsu; Fang, Shr-Shin

2008-05-13

This study presents a novel design of an easily stripped bi-layer composite that consists of an upper layer of a soybean protein non-woven fabric coated with a lower layer, a genipin-crosslinked chitosan film, as a wound dressing material. This study examines the in vitro properties of the genipin-crosslinked chitosan film and the bi-layer composite. Furthermore, in vivo experiments are conducted to study wounds treated with the composite in a rat model. Experimental results show that the degree of crosslinking and the in vitro degradation rate of the genipin-crosslinked chitosan films can be controlled by varying the genipin contents. In addition, the genipin contents should exceed 0.025 wt.-% of the chitosan-based material if complete crosslinking reactions between genipin and chitosan molecules are required. Water contact angle analysis shows that the genipin-crosslinked chitosan film is not highly hydrophilic; therefore, the genipin-crosslinked chitosan layer is not entangled with the soybean protein non-woven fabric, which forms an easily stripped interface layer between them. Furthermore, this new wound dressing material provides adequate moisture, thereby minimizing the risk of wound dehydration, and exhibits good mechanical properties. The in vivo histological assessment results reveal that epithelialization and reconstruction of the wound are achieved by covering the wound with the composite, and the composite is easily stripped from the wound surface without damaging newly regenerated tissue.

Finite element analysis of the stiffness of fabric reinforced composites

NASA Technical Reports Server (NTRS)

Foye, R. L.

1992-01-01

The objective of this work is the prediction of all three dimensional elastic moduli of textile fabric reinforced composites. The analysis is general enough for use with complex reinforcing geometries and capable of subsequent improvements. It places no restrictions on fabric microgeometry except that the unit cell be determinate and rectangular. The unit cell is divided into rectangular subcells in which the reinforcing geometries are easier to define and analyze. The analysis, based on inhomogeneous finite elements, is applied to a variety of weave, braid, and knit reinforced composites. Some of these predictions are correlated to test data.

2D net shape weaving for cost effective manufacture of textile reinforced composites

NASA Astrophysics Data System (ADS)

Vo, D. M. P.; Kern, M.; Hoffmann, G.; Cherif, C.

2017-10-01

Despite significant weight and performance advantages over metal parts, the today’s demand for fibre-reinforced polymer composites (FRPC) has been limited mainly by their large manufacturing cost. The combination of dry textile preforms and low-cost consolidation processes such as resin transfer molding (RTM) has been appointed as a promising approach to low-cost FRPC manufacture. At the current state of the art, tooling and impregnation technology is well understood whereas preform fabrication technology has not been developed effectively. This paper presents an advanced 2D net shape weaving technology developed with the aim to establish a more cost effective system for the manufacture of dry textile preforms for FRPC. 2D net shape weaving is developed based on open reed weave (ORW) technology and enables the manufacture of 2D contoured woven fabrics with firm edge, so that oversize cutting and hand trimming after molding are no longer required. The introduction of 2D net shape woven fabrics helps to reduce material waste, cycle time and preform manufacturing cost significantly. Furthermore, higher grade of automation in preform fabrication can be achieved.

Friction and Wear Behavior of Carbon Fabric-Reinforced Epoxy Composites

NASA Astrophysics Data System (ADS)

Şahin, Y.; De Baets, Patrick

2017-12-01

Besides intrinsic material properties, weight/energy savings and wear performance play an important role in the selection of materials for any engineering application. The tribological behavior of carbon fabric-reinforced epoxy composites produced by molding technique was investigated using a reciprocating pin-on-plate configuration. It was shown that the wear rate considerably decreased (by a factor of approx. 8) with the introduction of the reinforcing carbon fabric into the epoxy matrix. It was observed that the wear rate of the tested composites increased with an increase in normal load. Moreover, the coefficient of friction for epoxy/steel and composites/steel tribo-pairs was also determined and decreased with increasing load. By means of scanning electron microscopy of the wear tracks, different wear mechanisms such as matrix wear, matrix fatigue and cracking, matrix debris formation for neat epoxy together with fabric/fiber thinning, fabric breakage and fabric/matrix debonding for the reinforced epoxy could be distinguished.

Composite metal foil and ceramic fabric materials

DOEpatents

Webb, B.J.; Antoniak, Z.I.; Prater, J.T.; DeSteese, J.G.

1992-03-24

The invention comprises new materials useful in a wide variety of terrestrial and space applications. In one aspect, the invention comprises a flexible cloth-like material comprising a layer of flexible woven ceramic fabric bonded with a layer of metallic foil. In another aspect, the invention includes a flexible fluid impermeable barrier comprising a flexible woven ceramic fabric layer having metal wire woven therein. A metallic foil layer is incontinuously welded to the woven metal wire. In yet another aspect, the invention includes a material comprising a layer of flexible woven ceramic fabric bonded with a layer of an organic polymer. In still another aspect, the invention includes a rigid fabric structure comprising a flexible woven ceramic fabric and a resinous support material which has been hardened as the direct result of exposure to ultraviolet light. Inventive methods for producing such material are also disclosed. 11 figs.

Reduction of skin bacteria in theatre air with comfortable, non-woven disposable clothing for operating-theatre staff.

PubMed Central

Mitchell, N J; Evans, D S; Kerr, A

1978-01-01

Conventional loose-weave cotton operating garments were compared with clothing of a non-woven fabric to test their efficacy in reducing the dispersal of skin bacteria into theatre air. When men wore operating suits made of the non-woven fabric dispersal of skin bacteria was reduced by 72%. When all the operating-theatre staff wore suits and dresses of this fabric air bacterial counts during operating sessions were reduced by 55%; no reduction occurred when the fabric was worn by only the scrubbed team. The lowest levels of microbial contamination of the air in the operating theatre occurred when both the unscrubbed and scrubbed theatre staff wore clothes of non-woven fabric. PMID:630302

A comprehensive study of woven carbon fiber-reinforced nylon 6 composites

NASA Astrophysics Data System (ADS)

Pillay, Selvum

Liquid molding of thermoset composites has become very popular in all industry sectors, including aerospace, automotive, mass transit, and sporting goods, but the cost of materials and processing has limited the use to high-end applications. Thermoplastic composites are relatively cheap; however, the use has been limited to components with short fiber reinforcing. The high melt viscosity and short processing window precludes their use in the liquid molding of large structures and applications with continuous fiber reinforcement. The current research addresses the processing parameters, methodology, and limitations of vacuum assisted resin transfer molding (VARTM) of carbon fabric-reinforced, thermoplastic polyamide 6 (PA6). The material used is casting grade PA6. The process developed for using VARTM to produce carbon fabric-reinforced PA6 composites is explained in detail. The effects of infusion temperature and flow distance on the fiber weight fraction and crystallinity of the PA6 resin are presented. The degree of conversion from monomer to polymer was determined. Microscopic studies to show the wet-out of the fibers at the filament level are also presented. Tensile, flexural, short beam shear strength (SBSS), and low-velocity impact test results are presented and compared to a equivalent thermoset matrix composite. The rubber toughened epoxy system (SC-15) was chosen for the comparative study because the system has been especially developed to overcome the brittle nature of epoxy composites. The environmental effects of moisture and ultraviolet (UV) radiation on the carbon/nylon 6 composite were investigated. The samples were immersed in boiling water for 100 hr, and mechanical tests were conducted. Results showed that moisture causes plasticization of the matrix and attacks the fiber matrix interface. This leads to deterioration of the mechanical properties. The samples were also exposed to UV for up to 600 hr, and post exposure tests were conducted. The

Bending Behavior of Plain-Woven Fabric Air Beams: Fluid-Structure Interaction Approach

DTIC Science & Technology

2006-09-01

hoses . The warp yarns were aligned in the longitudinal direction of the fire hose and the weft yams, orthogonal to the warp yams, were aligned in the...both terms. Plain-woven air beams typically operate at low-pressure levels (less than those for triaxial-woven or braided air beams) because of safety

Thermal and Structural Performance of Woven Carbon Cloth For Adaptive Deployable Entry and Placement Technology

NASA Technical Reports Server (NTRS)

Arnold, James O.; Peterson, Keith H.; Yount, Bryan C.; Schneider, Nigel; Chavez-Garcia, Jose

2013-01-01

Arcjet testing and analysis of a three-dimensional (3D) woven carbon fabric has shown that it can be used as a thermal protection system and as a load bearing structural component for a low ballistic coefficient hypersonic decelerator called ADEPT (Adaptive Deployable Entry and Placement Technology). Results of arcjet tests proved that the 3D woven carbon fabric can withstand flight-like heating while under flight-like biaxial mechanical loads representative of those encountered during shallow entry flight path angles into the atmosphere of Venus. Importantly, the arcjet test results have been used to extend a preliminary material thermal response model based on previous testing of the same 3D woven carbon fabric under uni-axial mechanical loading.

Personnel occupied woven envelope robot

NASA Technical Reports Server (NTRS)

Wessling, F. C.

1986-01-01

The use of nonmetallic or fabric structures for space application is considered. The following structures are suggested: (1) unpressurized space hangars; (2) extendable tunnels for soft docking; and (3) manned habitat for space stations, storage facilities, and work structures. The uses of the tunnel as a passageway: for personnel and equipment, eliminating extravehicular activity, for access to a control cabin on a space crane and between free flyers and the space station are outlined. The personnal occupied woven envelope robot (POWER) device is shown. The woven envelope (tunnel) acts as part of the boom of a crane. Potential applications of POWER are outlined. Several possible deflection mechanisms and design criteria are determined.

Micromechanics of fatigue in woven and stitched composites

NASA Technical Reports Server (NTRS)

Cox, B. N.; Carter, W. C.; Dadkhah, M. S.; Morris, W. L.

1994-01-01

The goals of this research program were to: (1) determine how microstructural factors, especially the architecture of reinforcing fibers, control stiffness, strength, and fatigue life in 3D woven composites; (2) identify mechanisms of failure; (3) model composite stiffness; (4) model notched and unnotched strength; and (5) model fatigue life. We have examined a total of eleven different angle and orthogonal interlock woven composites. Extensive testing has revealed that these 3D woven composites possess an extraordinary combination of strength, damage tolerance, and notch insensitivity in compression and tension and in monotonic and cyclic loading. In many important regards, 3D woven composites far outstrip conventional 2D laminates or stitched laminates. Detailed microscopic analysis of damage has led to a comprehensive picture of the essential mechanisms of failure and how they are related to the reinforcement geometry. The critical characteristics of the weave architecture that promote favorable properties have been identified. Key parameters are tow size and the distributions in space and strength of geometrical flaws. The geometrical flaws should be regarded as controllable characteristics of the weave in design and manufacture. In addressing our goals, the simplest possible models of properties were always sought, in a blend of old and new modeling concepts. Nevertheless, certain properties, especially regarding damage tolerance, ultimate failure, and the detailed effects of weave architecture, require computationally intensive stochastic modeling. We have developed a new model, the 'binary model,' to carry out such tasks in the most efficient manner and with faithful representation of crucial mechanisms. This is the final report for contract NAS1-18840. It covers all work from April 1989 up to the conclusion of the program in January 1993.

Living nanofiber yarn-based woven biotextiles for tendon tissue engineering using cell tri-culture and mechanical stimulation.

PubMed

Wu, Shaohua; Wang, Ying; Streubel, Philipp N; Duan, Bin

2017-10-15

Non-woven nanofibrous scaffolds have been developed for tendon graft application by using electrospinning strategies. However, electrospun nanofibrous scaffolds face some obstacles and limitations, including suboptimal scaffold structure, weak tensile and suture-retention strengths, and compact structure for cell infiltration. In this work, a novel nanofibrous, woven biotextile, fabricated based on electrospun nanofiber yarns, was implemented as a tissue engineered tendon scaffold. Based on our modified electrospinning setup, polycaprolactone (PCL) nanofiber yarns were fabricated with reproducible quality, and were further processed into plain-weaving fabrics interlaced with polylactic acid (PLA) multifilaments. Nonwoven nanofibrous PCL meshes with random or aligned fiber structures were generated using typical electrospinning as comparative counterparts. The woven fabrics contained 3D aligned microstructures with significantly larger pore size and obviously enhanced tensile mechanical properties than their nonwoven counterparts. The biological results revealed that cell proliferation and infiltration, along with the expression of tendon-specific genes by human adipose derived mesenchymal stem cells (HADMSC) and human tenocytes (HT), were significantly enhanced on the woven fabrics compared with those on randomly-oriented or aligned nanofiber meshes. Co-cultures of HADMSC with HT or human umbilical vein endothelial cells (HUVEC) on woven fabrics significantly upregulated the functional expression of most tenogenic markers. HADMSC/HT/HUVEC tri-culture on woven fabrics showed the highest upregulation of most tendon-associated markers than all the other mono- and co-culture groups. Furthermore, we conditioned the tri-cultured constructs with dynamic conditioning and demonstrated that dynamic stretch promoted total collagen secretion and tenogenic differentiation. Our nanofiber yarn-based biotextiles have significant potential to be used as engineered scaffolds to

Comparison of spike and aerosol challenge tests for the recovery of viable influenza virus from non-woven fabrics.

PubMed

Zuo, Zhili; de Abin, Martha; Chander, Yogesh; Kuehn, Thomas H; Goyal, Sagar M; Pui, David Y H

2013-09-01

To experimentally determine the survival kinetics of influenza virus on personal protective equipment (PPE) and to evaluate the risk of virus transfer from PPE, it is important to compare the effects on virus recovery of the method used to contaminate the PPE with virus and the type of eluent used to recover it. Avian influenza virus (AIV) was applied as a liquid suspension (spike test) and as an aerosol to three types of non-woven fabrics [polypropylene (PP), polyester (PET), and polyamide (Nylon)] that are commonly used in the manufacture of PPE. This was followed by virus recovery using eight different eluents (phosphate-buffered saline, minimum essential medium, and 1.5% or 3.0% beef extract at pH 7, 8, or 9). For spike tests, no statistically significant difference was found in virus recovery using any of the eluents tested. Hydrophobic surfaces (PP and PET) yielded higher spiked virus recovery than hydrophilic Nylon. From all materials, the virus recovery was much lower in aerosol challenge tests than in spike tests. Significant differences were found in the recovery of viable AIV from non-woven fabrics between spike and aerosol challenge tests. The findings of this study demonstrate the need for realistic aerosol challenge tests rather than liquid spike tests in studies of virus survival on surfaces where airborne transmission of influenza virus may get involved. © 2013 John Wiley & Sons Ltd.

Infiltration behaviour of liquids over fibres or woven

NASA Astrophysics Data System (ADS)

Martinez, M. A.; Abenojar, J.; Enciso, B.; Lopez de Armentia, S.

2018-05-01

The high porosity of fabrics and fibres have hindered the study of the interaction between fluids and those kind of materials. In order to understand penetration mechanisms of polymeric matrices or woven sealing, some properties such as wettability or capillarity must be analysed. The fluid speed through some woven could be compared with metallic meshes in those is easy to determine pores size. In this work it is tried to solve these problems from a theoretical point of view by using hydrostatic laws and capillarity effect.

Fabrication of tungsten wire reinforced nickel-base alloy composites

NASA Technical Reports Server (NTRS)

Brentnall, W. D.; Toth, I. J.

1974-01-01

Fabrication methods for tungsten fiber reinforced nickel-base superalloy composites were investigated. Three matrix alloys in pre-alloyed powder or rolled sheet form were evaluated in terms of fabricability into composite monotape and multi-ply forms. The utility of monotapes for fabricating more complex shapes was demonstrated. Preliminary 1093C (2000F) stress rupture tests indicated that efficient utilization of fiber strength was achieved in composites fabricated by diffusion bonding processes. The fabrication of thermal fatigue specimens is also described.

Fabrication of Fiber-Reinforced Celsian Matrix Composites

NASA Technical Reports Server (NTRS)

Bansal, Narottam P.; Setlock, John A.

2000-01-01

A method has been developed for the fabrication of small diameter, multifilament tow fiber reinforced ceramic matrix composites. Its application has been successfully demonstrated for the Hi-Nicalon/celsian system. Strong and tough celsian matrix composites, reinforced with BN/SiC-coated Hi-Nicalon fibers, have been fabricated by infiltrating the fiber tows with the matrix slurry, winding the tows on a drum, cutting and stacking of the prepreg tapes in the desired orientation, and hot pressing. The monoclinic celsian phase in the matrix was produced in situ, during hot pressing, from the 0.75BaO-0.25SrO-Al2O3-2SiO2 mixed precursor synthesized by solid state reaction from metal oxides. Hot pressing resulted in almost fully dense fiber-reinforced composites. The unidirectional composites having approx. 42 vol% of fibers exhibited graceful failure with extensive fiber pullout in three-point bend tests at room temperature. Values of yield stress and strain were 435 +/- 35 MPa and 0.27 +/- 0.01 percent, respectively, and ultimate strengths of 900 +/- 60 MPa were observed. The Young's modulus of the composites was measured to be 165 +/- 5 GPa.

Woven graphite epoxy composite test specimens with glass buffer strips

NASA Technical Reports Server (NTRS)

Bonnar, G. R.; Palmer, R. J.

1982-01-01

Woven unidirectional graphite cloth with bands of fiberglass replacing the graphite in discrete lengthwise locations was impregnated with epoxy resin and used to fabricate a series of composite tensile and shear specimens. The finished panels, with the fiberglass buffer strips, were tested. Details of the fabrication process are reported.

A Comparison of the Fatigue Performance of Woven and Non-Woven CFRP (carbon Fibre Reinforced Plastics)

DTIC Science & Technology

1985-06-01

certain polymer fibres may defibrillate through exposure to fatigae loading and 20severe environments and subsequently also fail by fibre...fibre by weight than two non-woven plies.- The laminates were stored in a controlled environment at 230C and 652 relative humidity for at least 3 months...instability triggered by the defibrillation . tn fatisue the resin and the fibre/matrix interface become damaged ind are len able to support the fibres, thus

Fabrication Routes for Continuous Fiber-Reinforced Ceramic Composites (CFCC)

NASA Technical Reports Server (NTRS)

DiCarlo, James A.; Bansal, Narottam P.

1998-01-01

The primary approaches used for fabrication of continuous fiber-reinforced ceramic composite (CFCC) components have been reviewed. The CFCC fabrication issues related to fiber, interface, and matrix have been analyzed. The capabilities, advantages and limitations of the five matrix-infiltration routes have been compared and discussed. Today, the best fabrication route for the CFCC end-user is not clear and compromises need to be made depending on the details of the CFCC application. However, with time, this problem should be reduced as research continues to develop advanced CFCC constituents and fabrication routes.

Fabrication Routes for Continuous Fiber-Reinforced Ceramic Composites (CFCC)

NASA Technical Reports Server (NTRS)

DiCarlo, James A.; Bansal, Narottam P.

1998-01-01

The primary approaches used for fabrication of continuous fiber-reinforced ceramic composite (CFCC) components have been reviewed. The CFCC fabrication issues related to fiber, interface, and matrix have been analyzed. The capabilities. advantages and limitations of the five matrix-infiltration routes have been compared and discussed. Today. the best fabrication route for the CFCC end-user is not clear and compromises need to be made depending on the details of the CFCC application. However, with time, this problem should be reduced as research continues to develop advanced CFCC constituents and fabrication routes.

Two Dimensional (2D) P-Aramid Dry Multi-Layered Woven Fabrics Deformational Behaviour for Technical Applications

NASA Astrophysics Data System (ADS)

Abtew, M. A.; Loghin, C.; Cristian, I.; Boussu, F.; Bruniaux, P.; Chen, Y.; Wang, L.

2018-06-01

In today’s scenario for the various technical applications, from composites to body armour, the material mouldability along with its mechanical property become very important. In the present study, two dimensional (2D) woven fabrics made of para-aramid high performance fibres in multi-layer dry structure were used for investigating different forming characteristics. The different layers were arranged with 0°/90° orientation for deep drawing formability test to analyse the effect of number of layers and blank-holder pressure (BHP) during the test. Specific preforming device with low speed forming process and predefined hemispherical shape of punch has been applied. Using fine photographic analysis, some important 2D multi-layer fabrics forming characteristics i.e., material drawing-in, surface shear angle etc. from the imposed deformation have been observed, measured and analysed for better understanding and co MPa rison. The result revealed that the mouldability behaviour of the multi-layered dry textile fabric preforms is directional, and closely dependent on blank-holding pressure and number of layers. This indicates both parameters should be carefully considered while material deformation to avoid the formation of wrinkling and maintain other mechanical properties on final application.

Performance of Selected Fabrics on the Decontaminable Litter and Litter Mattress to Correct a Problem of Unexpected Sliding during Patient Loading on a C-9 (Nightingale) Aircraft

DTIC Science & Technology

1992-01-30

Agent Resistant Coating, retractable nylon handles, ethylene propylenediene monomer ( EPDM ) rubber securing straps, and a woven monofilament polypropylene...without Z-folds: overlapping layers of fabric sewn as reinforcement in the cover opposite the spreader bars. These covers were made from fabrics that...problem is not isolated to the decon litter and mattress. Comparable slippage should be expected when the vinyl mattress is used with the new nylon

Fabrication and characterization of high impact hybrid matrix composites from thermoset resin and dyneema-glass fabric reinforcement

NASA Astrophysics Data System (ADS)

Patel, R. H.; Sharma, S.; Pansuriya, T.; Malgani, E. V.; Sevkani, V.

2018-05-01

Hybrid composites have been fabricated by hand lay-up technique with epoxy resin and diethylene tri amine as a hardener for high impact energy absorption with sandwich stacking of different reinforcements of dyneema and glass fabric. High impact grade composites are nowadays gaining a lot of importance in the field of high mechanical load bearing applications, ballistics and bulletproofing. The present work emphases on the fabrication and mechanical properties of the hybrid composites of cut resistant dyneema fabric along with glass fabric reinforced in the thermosetting resin. i.e. epoxy. The prime importance while fabricating such materials have been given to the processing along with selection of the raw materials. High impact resistive materials with low density and henceforth low weight have been manufactured and characterized by IZOD impact tester, UTM, Archimedes density meter and SEM. Throughout the work, satisfactory results have been obtained. Impact resistance was observed to be boosted three times as that of the reference sample of glass fabric and epoxy. The density of the hybrid composite is observed to be 25% as that of the reference sample.

Mechanisms of compressive failure in woven composites and stitched laminates

NASA Technical Reports Server (NTRS)

Cox, B. N.; Dadkhah, M. S.; Inman, R. V.; Morris, W. L.; Schroeder, S.

1992-01-01

Stitched laminates and angle interlock woven composites have been studied in uniaxial, in-plane, monotonic compression. Failure mechanisms have been found to depend strongly on both the reinforcement architecture and the degree of constraint imposed by the loading grips. Stitched laminates show higher compressive strength, but are brittle, possessing no load bearing capacity beyond the strain for peak load. Post-mortem inspection shows a localized shear band of buckled and broken fibers, which is evidently the product of an unstably propagating kink band. Similar shear bands are found in the woven composites if the constraint of lateral displacements is weak; but, under strong constraint, damage is not localized but distributed throughout the gauge section. While the woven composites tested are weaker than the stitched laminates, they continue to bear significant loads to compressive strains of approx. 15 percent, even when most damage is confined to a shear band.

Fibre reinforced ceramic matrix composite fabrication by electrophoretic infiltration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kooner, S.; Campaniello, J.J.; Pickering, S.

Electrophoretic infiltration is a novel technique for the fabrication of fibre reinforced composites. The fibres are arranged as one of the electrodes such that deposition of the colloidal ceramic occurs in the fibre preform. This method has been investigated for the composite system of carbon fibre reinforced Si{sub 3}N{sub 4} and has produced green composite microstructures with good infiltration uniformity and fibre distribution and few macro defects.

Studies on fabrication of glass fiber reinforced composites using polymer blends

NASA Astrophysics Data System (ADS)

Patel, R. H.; Kachhia, P. H.; Patel, S. N.; Rathod, S. T.; Valand, J. K.

2018-05-01

Glass fiber reinforced PVC/NBR composites have been fabricated via hot compression moulding process. PVC is brittle in nature and thus lower thermal stability. Therefore, to improve the toughness of PVC, NBR was incorporated in certain proportions. As both are polar and thus they are compatible. To improve the strength property further, these blends were used to fabricate glass fiber reinforced composites. SEM micrograph shows good wettability of the blend with glass fibers resulting in proper bonding which increase the strength of the composites.

Present State of the Art of Composite Fabric Forming: Geometrical and Mechanical Approaches

PubMed Central

Cherouat, Abel; Borouchaki, Houman

2009-01-01

Continuous fibre reinforced composites are now firmly established engineering materials for the manufacture of components in the automotive and aerospace industries. In this respect, composite fabrics provide flexibility in the design manufacture. The ability to define the ply shapes and material orientation has allowed engineers to optimize the composite properties of the parts. The formulation of new numerical models for the simulation of the composite forming processes must allow for reduction in the delay in manufacturing and an optimization of costs in an integrated design approach. We propose two approaches to simulate the deformation of woven fabrics: geometrical and mechanical approaches.

Tensile and Flexural Properties of Cement Composites Reinforced with Flax Nonwoven Fabrics

PubMed Central

Claramunt, Josep; Ventura, Heura; Fernández-Carrasco, Lucía J; Ardanuy, Mònica

2017-01-01

The aim of this study is to develop a process to produce high-performance cement-based composites reinforced with flax nonwoven fabrics, analyzing the influence of the fabric structure—thickness and entanglement—on mechanical behavior under flexural and tensile loadings. For this purpose, composite with flax nonwoven fabrics with different thicknesses were first prepared and their cement infiltration was evaluated with backscattered electron (BSE) images. The nonwoven fabrics with the optimized thickness were then subjected to a water treatment to improve their stability to humid environments and the fiber-matrix adhesion. For a fixed thickness, the effect of the nonwoven entanglement on the mechanical behavior was evaluated under flexural and direct tension tests. The obtained results indicate that the flax nonwoven fabric reinforcement leads to cement composites with substantial enhancement of ductility. PMID:28772573

Thermomechanical Performance of C and SiC Multilayer, Fiber-Reinforced, CVI SiC Matrix Composites

NASA Technical Reports Server (NTRS)

Morscher, Gregory N.; Singh, Mrityunjay

2004-01-01

Hybrid fiber approaches have been attempted in the past to alloy desirable properties of different fiber-types for mechanical properties, thermal stress management, and oxidation resistance. Such an approach has potential for the CrSiC and SiCrSiC composite systems. SiC matrix composites with different stacking sequences of woven C fiber (T300) layers and woven Sic fiber (Hi-NicalonTM) layers were fabricated using the standard CVI process. Delamination occurred to some extent due to thermal mismatch for all of the composites. However, for the composites with a more uniform stacking sequence, minimal delamination occurred, enabling tensile properties to be determined at room temperature and elevated temperatures (stress-rupture in air). Composites were seal-coated with a CVI SiC layer as well as a proprietary C-B-Si (CBS) layer. Definite improvement in rupture behavior was observed in air for composites with increasing SiC fiber content and a CBS layer. The results will be compared to standard C fiber reinforced CVI SiC matrix and Hi-Nicalon reinforced CVI SiC matrix composites.

Recent advancements in mechanical characterisation of 3D woven composites

NASA Astrophysics Data System (ADS)

Saleh, Mohamed Nasr; Soutis, Constantinos

2017-12-01

Three dimensional (3D) woven composites have attracted the interest of academia and industry thanks to their damage tolerance characteristics and automated fabric manufacturing. Although much research has been conducted to investigate their out-of-plane "through thickness" properties, still their in-plane properties are not fully understood and rely on extensive experimentation. To date, the literature lacks an inclusive summary of the mechanical characterisation for 3D woven composites. Therefore, the objective of this paper is to provide a comprehensive review of the available research studies on 3D woven composites mechanical characterisation, with less emphasis on the out-of-plane response, but an in-depth review of the in-plane response "un-notched vs. notched". The paper highlights the knowledge gap in the literature of 3D woven composites, suggesting opportunities for future research in this field and a room for improvement in utilising Non-Destructive Techniques (NDT), such as Digital Image Correlation (DIC), Acoustic Emission (AE) and X-ray Computed Tomography (CT), for observing damage initiation and evolution in 3D woven composites that could be used to calibrate and evaluate analytical and numerical models.

Drip bloodstain appearance on inclined apparel fabrics: Effect of prior-laundering, fibre content and fabric structure.

PubMed

de Castro, Therese C; Carr, Debra J; Taylor, Michael C; Kieser, Jules A; Duncan, Warwick

2016-09-01

The interaction of blood and fabrics is currently a 'hot topic', since the understanding and interpretation of these stains is still in its infancy. A recent simplified perpendicular impact experimental programme considering bloodstains generated on fabrics laid the foundations for understanding more complex scenarios. Blood rarely impacts apparel fabrics perpendicular; therefore a systematic study was conducted to characterise the appearance of drip stains on inclined fabrics. The final drip stain appearance for 45° and 15° impact angles on torso apparel fabrics (100% cotton plain woven, 100% polyester plain woven, a blend of polyester and cotton plain woven and 100% cotton single jersey knit) that had been laundered for six, 26 and 52 cycles prior to testing was investigated. The relationship between drop parameters (height and volume), angle and the stain characteristics (parent stain area, axis 1 and 2 and number of satellite stains) for each fabric was examined using analysis of variance. The appearance of the drip stains on these fabrics was distorted, in comparison to drip stains on hard-smooth surface. Examining the parent stain allowed for classification of stains occurring at an angle, however the same could not be said for the satellite stains produced. All of the dried stains visible on the surface of the fabric were larger than just after the impacting event, indicating within fabric spreading of blood due to capillary force (wicking). The cotton-containing fabrics spread the blood within the fabrics in all directions along the stain's circumference, while spreading within the polyester plain woven fabric occurred in only the weft (width of the fabric) and warp (length) directions. Laundering affected the formation of bloodstain on the blend plain woven fabric at both impact angles, although not all characteristics were significantly affected for the three impact conditions considered. The bloodstain characteristics varied due to the fibre content

Effect of Sericin on Mechanical Behavior of Composite Material Reinforced by Silk Woven Fabric

NASA Astrophysics Data System (ADS)

Kimura, Teruo; Ino, Haruhiro; Hanada, Koji; Katori, Sigetaka

Recent, attention has been given to shift from glass fibers and carbon fibers to natural fibers for FRP composites for the goal of protecting the environment. This paper concerned with the application of silk fabric for composite materials. Polypropylene (PP) was used for the matrix material and the silk fabric composites were molded using a compression molding method. Especially, the effect of sericin on mechanical behaviors of composite materials was discussed. Good adhesion between silk and PP was obtained by removing the sericin existing around the fibroin. The tensile modulus of composite decreased with decreasing the sericin because of the flexibility of silk fibers without sericin. In particular, the higher Izod impact value was obtained for the composites containing the silk fibers without sericin.

Modelling and simulating the forming of new dry automated lay-up reinforcements for primary structures

NASA Astrophysics Data System (ADS)

Bouquerel, Laure; Moulin, Nicolas; Drapier, Sylvain; Boisse, Philippe; Beraud, Jean-Marc

2017-10-01

While weight has been so far the main driver for the development of prepreg based-composites solutions for aeronautics, a new weight-cost trade-off tends to drive choices for next-generation aircrafts. As a response, Hexcel has designed a new dry reinforcement type for aircraft primary structures, which combines the benefits of automation, out-of-autoclave process cost-effectiveness, and mechanical performances competitive to prepreg solutions: HiTape® is a unidirectional (UD) dry carbon reinforcement with thermoplastic veil on each side designed for aircraft primary structures [1-3]. One privileged process route for HiTape® in high volume automated processes consists in forming initially flat dry reinforcement stacks, before resin infusion [4] or injection. Simulation of the forming step aims at predicting the geometry and mechanical properties of the formed stack (so-called preform) for process optimisation. Extensive work has been carried out on prepreg and dry woven fabrics forming behaviour and simulation, but the interest for dry non-woven reinforcements has emerged more recently. Some work has been achieved on non crimp fabrics but studies on the forming behaviour of UDs are seldom and deal with UD prepregs only. Tension and bending in the fibre direction, along with inter-ply friction have been identified as the main mechanisms controlling the HiTape® response during forming. Bending has been characterised using a modified Peirce's flexometer [5] and inter-ply friction study is under development. Anisotropic hyperelastic constitutive models have been selected to represent the assumed decoupled deformation mechanisms. Model parameters are then identified from associated experimental results. For forming simulation, a continuous approach at the macroscopic scale has been selected first, and simulation is carried out in the Zset framework [6] using proper shell finite elements.

Structure and yarn sensor for fabric

DOEpatents

Mee, David K.; Allgood, Glenn O.; Mooney, Larry R.; Duncan, Michael G.; Turner, John C.; Treece, Dale A.

1998-01-01

A structure and yarn sensor for fabric directly determines pick density in a fabric thereby allowing fabric length and velocity to be calculated from a count of the picks made by the sensor over known time intervals. The structure and yarn sensor is also capable of detecting full length woven defects and fabric. As a result, an inexpensive on-line pick (or course) density measurement can be performed which allows a loom or knitting machine to be adjusted by either manual or automatic means to maintain closer fiber density tolerances. Such a sensor apparatus dramatically reduces fabric production costs and significantly improves fabric consistency and quality for woven or knitted fabric.

Analysis of knitted fabric reinforced flexible composites and applications in thermoforming

NASA Astrophysics Data System (ADS)

Bekisli, Burak

In this study, large deformation behavior of knitted fabric reinforced composites is investigated. In order to fully utilize the unique stretchability of knitted fabric reinforcements, elastomeric materials are used as the matrix material, resulting in "flexible composites" capable of reaching several hundred percent stretch before failing. These non-traditional composites are ideal candidates for many engineering applications where large deformation is desired, including energy/impact absorption and novel forming processes. A multi-level nonlinear finite element (FE) procedure is developed to analyze the deformation behavior of plain weft-knitted fabrics and the composites derived from these materials. The hierarchy of the model is composed of a 3D unit cell analysis (micro/meso-scale) and a 2D global analysis (macro scale). Using results from different numerical experiments performed in the micro/meso scale, a mechanical behavior database of knit fabric geometries is constructed, both for the uniaxial and biaxial stretch cases. Through an optimization procedure, these results are used to determine the mechanical properties of nonlinear truss elements needed for modeling in the macro scale. A hexagonal honeycomb structure, which closely resembles the knit fabric architecture, is formed using these nonlinear trusses. This truss structure is then used to efficiently model a large number of loops generally found in a fabric. Results from uniaxial experimental measurements are presented for knitted fabrics to validate the FE model. Appropriate hyperelastic material models are determined for the elastomeric matrix, using a curve fit to experimental data. Examples of raw fabric and composite deformation simulations in the global scale are presented in this study. Two types of composites are studied experimentally and numerically: (1) knitted fabric embedded in an elastomeric medium, and (2) the sandwich type composites with elastomeric skins and fabric core. The strain

Hemp reinforced composites: surface treatment, manufacturing method and fabric type effects

NASA Astrophysics Data System (ADS)

Cicalạ, G.; Cristaldi, G.; Recca, G.

2010-06-01

Hemp mats and weaved fabrics were used as received and after surface treatment as reinforcement for composites. Mercerization and amino silane surface treatments improved fibre/matrix adhesion and, as results, the mechanical properties of the composites were also improved. However, if surface treatment was too severe degradation of the mechanical properties of the single fibre was observed and this resulted in a reinforcing efficiency loss. Weaved fabrics obtained from twisted fibres in unidirectional and 0/90° architecture were used. The use of weaved fabrics lead to high improvements of composite mechanical properties despite the absence of fibre's surface treatment. The specimens manufactured by LRTM (Light Resin Transfer Moulding) showed enhanced mechanical properties compared to specimens made by hand lay up. Mechanical models were also used to predict the mechanical properties of the composites.

Three-dimensional fabric reinforced plastics for cryogenic use

NASA Astrophysics Data System (ADS)

Iwasaki, Y.; Yasuda, J.; Hirokawa, T.; Noma, K.; Nishijima, S.; Okada, T.

Three-dimensional fabric reinforced plastics (3DFRPs) have been developed as insulating and/or structural materials in superconducting magnets. Three-dimensional fabrics were designed with practical applications in fibre composites of 3DFRP. The mechanical properties such as Young's modulus, Poisson's ratio, tensile strength and the compressive strength down to liquid helium temperature were measured. Thermal contraction was also measured. The cryogenic characteristics of 3DFRPs were compared with those of conventional laminates. The newly developed 3DFRPs were found to show satisfactory characteristics not only at room temperature but also at low temperatures.

Increasing Mechanical Properties of 2-D-Structured Electrospun Nylon 6 Non-Woven Fiber Mats.

PubMed

Xiang, Chunhui; Frey, Margaret W

2016-04-07

Tensile strength, Young's modulus, and toughness of electrospun nylon 6 non-woven fiber mats were improved by increasing individual nanofiber strength and fiber-fiber load sharing. Single-walled carbon nanotubes (CNTs) were used as reinforcement to increase the strength of the electrospun nylon 6 nanofibers. Young's modulus, tensile strength, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % solutions increased 51%, 87%, and 136%, respectively, after incorporating 1 wt % CNTs into the nylon 6 nanofibers. Three methods were investigated to enhance fiber-fiber load sharing: increasing friction between fibers, thermal bonding, and solvent bonding. The addition of beaded nylon 6 nanofibers into the non-woven fiber mats to increase fiber-fiber friction resulted in a statistically significantly increase in Young's modulus over comparable smooth non-woven fiber mats. After annealing, tensile strength, elongation, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % + 10 wt % solutions increased 26%, 28%, and 68% compared to those from 20 wt % solutions. Solvent bonding with formic acid vapor at room temperature for 30 min caused increases of 56%, 67%, and 39% in the Young's modulus, tensile strength, and toughness of non-woven fiber mats, respectively. The increases attributed to increased individual nanofiber strength and solvent bonding synergistically resulted in the improvement of Young's modulus of the electrospun nylon 6 non-woven fiber mats.

Transverse isotropic modeling of the ballistic response of glass reinforced plastic composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, P.A.

1997-12-31

The use of glass reinforced plastic (GRP) composites is gaining significant attention in the DoD community for use in armor applications. These materials typically possess a laminate structure consisting of up to 100 plies, each of which is constructed of a glass woven roving fabric that reinforces a plastic matrix material. Current DoD attention is focused on a high strength, S-2 glass cross-weave (0/90) fabric reinforcing a polyester matrix material that forms each ply of laminate structure consisting anywhere from 20 to 70 plies. The resulting structure displays a material anisotropy that is, to a reasonable approximation, transversely isotropic. Whenmore » subjected to impact and penetration from a metal fragment projectile, the GRP displays damage and failure in an anisotropic manner due to various mechanisms such as matrix cracking, fiber fracture and pull-out, and fiber-matrix debonding. In this presentation, the author will describe the modeling effort to simulate the ballistic response of the GRP material described above using the transversely isotropic (TI) constitutive model which has been implemented in the shock physics code, CTH. The results of this effort suggest that the model is able to describe the delamination behavior of the material but has some difficulty capturing the in-plane (i.e., transverse) response of the laminate due to its cross-weave fabric reinforcement pattern which causes a departure from transverse isotropy.« less

Production Principles and Technological Development of Novel Woven Spacer Preforms and Integrated Stiffener Structures

NASA Astrophysics Data System (ADS)

Torun, Ahmet R.; Mountasir, Adil; Hoffmann, Gerald; Cherif, Chokri

2013-06-01

3D textile preforms offer a high potential to increase mechanical properties of composites and/or decrease manufacturing costs. Within the scope of this study, production principles were developed for complex spacer preforms and integrated stiffeners. These principles were applied through technological further development of the well-known face-to-face and terry weaving techniques. Various woven preforms were produced with Glass fibre/Polypropylene (GF/PP) Commingled yarns, however, the technology is suitable for any type of reinforcement yarns. U-shaped woven spacer preform was consolidated into a sandwich composite component for lightweight applications.

Hemp reinforced composites: surface treatment, manufacturing method and fabric type effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cicala, G.; Cristaldi, G.; Recca, G.

2010-06-02

Hemp mats and weaved fabrics were used as received and after surface treatment as reinforcement for composites. Mercerization and amino silane surface treatments improved fibre/matrix adhesion and, as results, the mechanical properties of the composites were also improved. However, if surface treatment was too severe degradation of the mechanical properties of the single fibre was observed and this resulted in a reinforcing efficiency loss. Weaved fabrics obtained from twisted fibres in unidirectional and 0/90 deg. architecture were used. The use of weaved fabrics lead to high improvements of composite mechanical properties despite the absence of fibre's surface treatment. The specimensmore » manufactured by LRTM (Light Resin Transfer Moulding) showed enhanced mechanical properties compared to specimens made by hand lay up. Mechanical models were also used to predict the mechanical properties of the composites.« less

Structure and yarn sensor for fabric

DOEpatents

Mee, D.K.; Allgood, G.O.; Mooney, L.R.; Duncan, M.G.; Turner, J.C.; Treece, D.A.

1998-10-20

A structure and yarn sensor for fabric directly determines pick density in a fabric thereby allowing fabric length and velocity to be calculated from a count of the picks made by the sensor over known time intervals. The structure and yarn sensor is also capable of detecting full length woven defects and fabric. As a result, an inexpensive on-line pick (or course) density measurement can be performed which allows a loom or knitting machine to be adjusted by either manual or automatic means to maintain closer fiber density tolerances. Such a sensor apparatus dramatically reduces fabric production costs and significantly improves fabric consistency and quality for woven or knitted fabric. 13 figs.

The effect of processing on the mechanical properties of self-reinforced composites

NASA Astrophysics Data System (ADS)

Hassani, Farzaneh; Martin, Peter J.; Falzon, Brian G.

2018-05-01

Hot-compaction is one of the most common manufacturing methods for creating recyclable all thermoplastic composites. The current work investigates the compaction of highly oriented self-reinforced fabrics with three processing methods to study the effect of pressure and temperature in the tensile mechanical properties of the consolidated laminates. Hot-press, calender roller and vacuum bag technique were adopted to consolidate bi-component polypropylene woven fabrics in a range of pressures and compaction temperatures. Hot-pressed samples exhibited the highest quality of compaction. The modulus of the hot-pressed samples increased with compaction temperature initially due to the improved interlayer bonding and decreased after a maximum at 150°C because of partial melting of the reinforcement phase. The calender roller technique exhibited to have smaller processing temperature window as the pressure is only applied for a short time and the fabrics start to shrink with increasing the processing temperature. The need for constraining the fabrics through the process is therefore found to be paramount. The Vacuum bag results showed this technique to be the least efficient method because of the low compaction pressure. Microscopic images and void content measurement of the consolidated samples further validate the results from tensile testing.

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

NASA Astrophysics Data System (ADS)

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

2017-01-01

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

Woven heat exchanger

DOEpatents

Piscitella, Roger R.

1987-01-01

In a woven ceramic heat exchanger using the basic tube-in-shell design, each heat exchanger consisting of tube sheets and tube, is woven separately. Individual heat exchangers are assembled in cross-flow configuration. Each heat exchanger is woven from high temperature ceramic fiber, the warp is continuous from tube to tube sheet providing a smooth transition and unitized construction.

Woven heat exchanger

DOEpatents

Piscitella, Roger R.

1987-05-05

In a woven ceramic heat exchanger using the basic tube-in-shell design, each heat exchanger consisting of tube sheets and tube, is woven separately. Individual heat exchangers are assembled in cross-flow configuration. Each heat exchanger is woven from high temperature ceramic fiber, the warp is continuous from tube to tube sheet providing a smooth transition and unitized construction.

Increasing Mechanical Properties of 2-D-Structured Electrospun Nylon 6 Non-Woven Fiber Mats

PubMed Central

Xiang, Chunhui; Frey, Margaret W.

2016-01-01

Tensile strength, Young’s modulus, and toughness of electrospun nylon 6 non-woven fiber mats were improved by increasing individual nanofiber strength and fiber–fiber load sharing. Single-walled carbon nanotubes (CNTs) were used as reinforcement to increase the strength of the electrospun nylon 6 nanofibers. Young’s modulus, tensile strength, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % solutions increased 51%, 87%, and 136%, respectively, after incorporating 1 wt % CNTs into the nylon 6 nanofibers. Three methods were investigated to enhance fiber–fiber load sharing: increasing friction between fibers, thermal bonding, and solvent bonding. The addition of beaded nylon 6 nanofibers into the non-woven fiber mats to increase fiber-fiber friction resulted in a statistically significantly increase in Young’s modulus over comparable smooth non-woven fiber mats. After annealing, tensile strength, elongation, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % + 10 wt % solutions increased 26%, 28%, and 68% compared to those from 20 wt % solutions. Solvent bonding with formic acid vapor at room temperature for 30 min caused increases of 56%, 67%, and 39% in the Young’s modulus, tensile strength, and toughness of non-woven fiber mats, respectively. The increases attributed to increased individual nanofiber strength and solvent bonding synergistically resulted in the improvement of Young’s modulus of the electrospun nylon 6 non-woven fiber mats. PMID:28773397

Self-deposition of Pt nanoparticles on graphene woven fabrics for enhanced hybrid Schottky junctions and photoelectrochemical solar cells.

PubMed

Kang, Zhe; Tan, Xinyu; Li, Xiao; Xiao, Ting; Zhang, Li; Lao, Junchao; Li, Xinming; Cheng, Shan; Xie, Dan; Zhu, Hongwei

2016-01-21

In this study, we demonstrated a self-deposition method to deposit Pt nanoparticles (NPs) on graphene woven fabrics (GWF) to improve the performance of graphene-on-silicon solar cells. The deposition of Pt NPs increased the work function of GWF and reduced the sheet resistance of GWF, thereby improving the power conversion efficiency (PCE) of graphene-on-silicon solar cells. The PCE (>10%) was further enhanced via solid electrolyte coating of the hybrid Schottky junction in the photoelectrochemical solar cells. These results suggest that the combination of self-deposition of Pt NPs and solid-state electrolyte coating of graphene-on-silicon is a promising way to produce high performance graphene-on-semiconductor solar cells.

Micromechanics Fatigue Damage Analysis Modeling for Fabric Reinforced Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Min, J. B.; Xue, D.; Shi, Y.

2013-01-01

A micromechanics analysis modeling method was developed to analyze the damage progression and fatigue failure of fabric reinforced composite structures, especially for the brittle ceramic matrix material composites. A repeating unit cell concept of fabric reinforced composites was used to represent the global composite structure. The thermal and mechanical properties of the repeating unit cell were considered as the same as those of the global composite structure. The three-phase micromechanics, the shear-lag, and the continuum fracture mechanics models were integrated with a statistical model in the repeating unit cell to predict the progressive damages and fatigue life of the composite structures. The global structure failure was defined as the loss of loading capability of the repeating unit cell, which depends on the stiffness reduction due to material slice failures and nonlinear material properties in the repeating unit cell. The present methodology is demonstrated with the analysis results evaluated through the experimental test performed with carbon fiber reinforced silicon carbide matrix plain weave composite specimens.

RC beams shear-strengthened with fabric-reinforced-cementitious-matrix (FRCM) composite

NASA Astrophysics Data System (ADS)

Loreto, Giovanni; Babaeidarabad, Saman; Leardini, Lorenzo; Nanni, Antonio

2015-12-01

The interest in retrofit/rehabilitation of existing concrete structures has increased due to degradation and/or introduction of more stringent design requirements. Among the externally-bonded strengthening systems fiber-reinforced polymers is the most widely known technology. Despite its effectiveness as a material system, the presence of an organic binder has some drawbacks that could be addressed by using in its place a cementitious binder as in fabric-reinforced cementitious matrix (FRCM) systems. The purpose of this paper is to evaluate the behavior of reinforced concrete (RC) beams strengthened in shear with U-wraps made of FRCM. An extensive experimental program was undertaken in order to understand and characterize this composite when used as a strengthening system. The laboratory results demonstrate the technical viability of FRCM for shear strengthening of RC beams. Based on the experimental and analytical results, FRCM increases shear strength but not proportionally to the number of fabric plies installed. On the other hand, FRCM failure modes are related with a high consistency to the amount of external reinforcement applied. Design considerations based on the algorithms proposed by ACI guidelines are also provided.

Fabrication Of Carbon-Boron Reinforced Dry Polymer Matrix Composite Tape

NASA Technical Reports Server (NTRS)

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

1999-01-01

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

Design and fabrication of a boron reinforced intertank skirt

NASA Technical Reports Server (NTRS)

Henshaw, J.; Roy, P. A.; Pylypetz, P.

1974-01-01

Analytical and experimental studies were performed to evaluate the structural efficiency of a boron reinforced shell, where the medium of reinforcement consists of hollow aluminum extrusions infiltrated with boron epoxy. Studies were completed for the design of a one-half scale minimum weight shell using boron reinforced stringers and boron reinforced rings. Parametric and iterative studies were completed for the design of minimum weight stringers, rings, shells without rings and shells with rings. Computer studies were completed for the final evaluation of a minimum weight shell using highly buckled minimum gage skin. The detail design is described of a practical minimum weight test shell which demonstrates a weight savings of 30% as compared to an all aluminum longitudinal stiffened shell. Sub-element tests were conducted on representative segments of the compression surface at maximum stress and also on segments of the load transfer joint. A 10 foot long, 77 inch diameter shell was fabricated from the design and delivered for further testing.

Rigid spine reinforced polymer microelectrode array probe and method of fabrication

DOEpatents

Tabada, Phillipe; Pannu, Satinderpall S

2014-05-27

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

Carbon Fiber Reinforced Carbon Composites Rotary Valves for Internal Combustion Engines

NASA Technical Reports Server (NTRS)

Northam, G. Burton (Inventor); Ransone, Philip O. (Inventor); Rivers, H. Kevin (Inventor)

1999-01-01

Carbon fiber reinforced carbon composite rotary, sleeve, and disc valves for internal combustion engines and the like are disclosed. The valves are formed from knitted or braided or warp-locked carbon fiber shapes. Also disclosed are valves fabricated from woven carbon fibers and from molded carbon matrix material. The valves of the present invention with their very low coefficient of thermal expansion and excellent thermal and self-lubrication properties, do not present the sealing and lubrication problems that have prevented rotary, sleeve, and disc valves from operating efficiently and reliably in the past. Also disclosed are a sealing tang to further improve sealing capabilities and anti-oxidation treatments.

Woven heat exchanger

DOEpatents

Piscitella, R.R.

1984-07-16

This invention relates to a heat exchanger for waste heat recovery from high temperature industrial exhaust streams. In a woven ceramic heat exchanger using the basic tube-in-shell design, each heat exchanger consisting of tube sheets and tube, is woven separately. Individual heat exchangers are assembled in cross-flow configuration. Each heat exchanger is woven from high temperature ceramic fiber, the warp is continuous from tube to tube sheet providing a smooth transition and unitized construction.

Photocatalytic oxidation of nitrogen oxides using TiO2 loading on woven glass fabric.

PubMed

Wang, Haiqiang; Wu, Zhongbiao; Zhao, Weirong; Guan, Baohong

2007-01-01

TiO2 loading on woven glass fabric is applied to treat nitrogen oxides (NOx) by photocatalytic oxidation (PCO). In this paper, the PCO behavior of NO at high concentrations was studied by PCO of NOx at source levels (20-168 ppm). The PCO efficiency reached 27% in this experiment, while the inlet NOx concentration was 168 ppm (147 ppm NO). The dependency of the reaction rate on several key influencing factors (relative humidity, space time, inlet concentration, oxygen percentage) was also studied. The results illustrate that the resulting hydroxyl radical and active oxide play an important role in the oxidation of NOx. The reactions are limited by the thermodynamic equilibrium after ca. 15s space time. A possible explanation for the catalyst deactivation is the accumulation of nitric acid and nitrous acid on the TiO2 surface during the PCO of NOx. However, the photocatalytic activity can be recovered with a simple heat treatment. The results from the study of the effect of the inlet concentration were described with the Langmuir-Hinshelwood model.

Tactile Sensing System Based on Arrays of Graphene Woven Microfabrics: Electromechanical Behavior and Electronic Skin Application.

PubMed

Yang, Tingting; Wang, Wen; Zhang, Hongze; Li, Xinming; Shi, Jidong; He, Yijia; Zheng, Quan-shui; Li, Zhihong; Zhu, Hongwei

2015-11-24

Nanomaterials serve as promising candidates for strain sensing due to unique electromechanical properties by appropriately assembling and tailoring their configurations. Through the crisscross interlacing of graphene microribbons in an over-and-under fashion, the obtained graphene woven fabric (GWF) indicates a good trade-off between sensitivity and stretchability compared with those in previous studies. In this work, the function of woven fabrics for highly sensitive strain sensing is investigated, although network configuration is always a strategy to retain resistance stability. The experimental and simulation results indicate that the ultrahigh mechanosensitivity with gauge factors of 500 under 2% strain is attributed to the macro-woven-fabric geometrical conformation of graphene, which induces a large interfacial resistance between the interlaced ribbons and the formation of microscale-controllable, locally oriented zigzag cracks near the crossover location, both of which have a synergistic effect on improving sensitivity. Meanwhile, the stretchability of the GWF could be tailored to as high as over 40% strain by adjusting graphene growth parameters and adopting oblique angle direction stretching simultaneously. We also demonstrate that sensors based on GWFs are applicable to human motion detection, sound signal acquisition, and spatially resolved monitoring of external stress distribution.

A spectral profile multiplexed FBG sensor network with application to strain measurement in a Kevlar woven fabric

NASA Astrophysics Data System (ADS)

Guo, Guodong; Hackney, Drew; Pankow, Mark; Peters, Kara

2017-04-01

A spectral profile division multiplexed fiber Bragg grating (FBG) sensor network is described in this paper. The unique spectral profile of each sensor in the network is identified as a distinct feature to be interrogated. Spectrum overlap is allowed under working conditions. Thus, a specific wavelength window does not need to be allocated to each sensor as in a wavelength division multiplexed (WDM) network. When the sensors are serially connected in the network, the spectrum output is expressed through a truncated series. To track the wavelength shift of each sensor, the identification problem is transformed to a nonlinear optimization problem, which is then solved by a modified dynamic multi-swarm particle swarm optimizer (DMS-PSO). To demonstrate the application of the developed network, a network consisting of four FBGs was integrated into a Kevlar woven fabric, which was under a quasi-static load imposed by an impactor head. Due to the substantial radial strain in the fabric, the spectrums of different FBGs were found to overlap during the loading process. With the developed interrogating method, the overlapped spectrum would be distinguished thus the wavelength shift of each sensor can be monitored.

Optimum processing parameters for the fabrication of twill flax fabric-reinforced polypropylene (PP) composites

NASA Astrophysics Data System (ADS)

Zuhudi, Nurul Zuhairah Mahmud; Minhat, Mulia; Shamsuddin, Mohd Hafizi; Isa, Mohd Dali; Nur, Nurhayati Mohd

2017-12-01

In recent years, natural fabric thermoplastic composites such as flax have received much attention due to its attractive capabilities for structural applications. It is crucial to study the processing of flax fabric materials in order to achieve good quality and cost-effectiveness in fibre reinforced composites. Though flax fabric has been widely utilized for several years in composite applications due to its high strength and abundance in nature, much work has been concentrated on short flax fibre and very little work focused on using flax fabric. The effectiveness of the flax fabric is expected to give higher strength performance due to its structure but the processing needs to be optimised. Flax fabric composites were fabricated using compression moulding due to its simplicity, gives good surface finish and relatively low cost in terms of labour and production. Further, the impregnation of the polymer into the fabric is easier in this process. As the fabric weave structure contributes to the impregnation quality which leads to the overall performance, the processing parameters of consolidation i.e. pressure, time, and weight fraction of fabric were optimized using the Taguchi method. This optimization enhances the consolidation quality of the composite by improving the composite mechanical properties, three main tests were conducted i.e. tensile, flexural and impact test. It is observed that the processing parameter significantly affected the consolidation and quality of composite.

Carbon Fiber Reinforced Carbon Composite Rotary Valve for an Internal Combustion Engine

NASA Technical Reports Server (NTRS)

Northam, G.Burton (Inventor); Ransone, Philip O. (Inventor); Rivers, H. Kevin (Inventor)

2000-01-01

Carbon fiber reinforced carbon composite rotary sleeve, and disc valves for internal combustion engines and the like are disclosed. The valves are formed from knitted or braided or wrap-locked carbon fiber shapes. Also disclosed are valves fabricated from woven carbon fibers and from molded carbon matrix material. The valves of the present invention with their very low coefficient of thermal expansion and excellent thermal and self-lubrication properties do not present the sealing and lubrication problems that have prevented rotary sleeve and disc valves from operating efficiently and reliably in the past. Also disclosed are a sealing tang to further improve sealing capabilities and anti-oxidation treatments.

Braided reinforced composite rods for the internal reinforcement of concrete

NASA Astrophysics Data System (ADS)

Gonilho Pereira, C.; Fangueiro, R.; Jalali, S.; Araujo, M.; Marques, P.

2008-05-01

This paper reports on the development of braided reinforced composite rods as a substitute for the steel reinforcement in concrete. The research work aims at understanding the mechanical behaviour of core-reinforced braided fabrics and braided reinforced composite rods, namely concerning the influence of the braiding angle, the type of core reinforcement fibre, and preloading and postloading conditions. The core-reinforced braided fabrics were made from polyester fibres for producing braided structures, and E-glass, carbon, HT polyethylene, and sisal fibres were used for the core reinforcement. The braided reinforced composite rods were obtained by impregnating the core-reinforced braided fabric with a vinyl ester resin. The preloading of the core-reinforced braided fabrics and the postloading of the braided reinforced composite rods were performed in three and two stages, respectively. The results of tensile tests carried out on different samples of core-reinforced braided fabrics are presented and discussed. The tensile and bending properties of the braided reinforced composite rods have been evaluated, and the results obtained are presented, discussed, and compared with those of conventional materials, such as steel.

Using woven carbon fiber fabric to construct gradient porous structure for passive direct methanol fuel cells

NASA Astrophysics Data System (ADS)

Yuan, Wei; Hu, Jinyi; Zhou, Bo; Deng, Jun; Zhang, Zhaochun; Tang, Yong

2015-09-01

The passive direct methanol fuel cell (DMFC) is a promising candidate power source for portable applications but has to deal with many technical challenges before practical use. This study presents a preliminary investigation on the use of a woven carbon fiber fabric (WCFF) for constructing a gradient porous structure based on the traditional design. The WCFF, carbon paper and carbon-black micro porous layer (MPL) combine into a carbon-based assembly which acts as a mass-transfer-controlling medium at the anode of a passive DMFC. Results show that this novel setup is able to significantly improve the cell performance and facilitate high-concentration operation. A maximum power density of 16.4 mWcm-2 is obtained when two layers of the WCFF are used at a methanol concentration of 8M. This work provides an effective method for using concentrated methanol with no need for major change of the fuel cell configuration.

Pressure Drop Across Woven Screens Under Uniform and Nonuniform Flow Conditions. [flow characteristics of water through Dutch twill and square weave fabrics

NASA Technical Reports Server (NTRS)

Ludewig, M.; Omori, S.; Rao, G. L.

1974-01-01

Tests were conducted to determine the experimental pressure drop and velocity data for water flowing through woven screens. The types of materials used are dutch twill and square weave fabrics. Pressure drop measures were made at four locations in a rectangular channel. The data are presented as change in pressure compared with the average entry velocity and the numerical relationship is determined by dividing the volumetric flow rate by the screen area open to flow. The equations of continuity and momentum are presented. A computer program listing an extension of a theoretical model and data from that computer program are included.

Effect of fabricated density and bamboo species on physical-mechanical properties of bamboo fiber bundle reinforced composites

Treesearch

Jiulong Xie; Jinqiu Qi; Tingxing Hu; Cornelis F. De Hoop; Chung Yun Hse; Todd F. Shupe

2016-01-01

Bamboo stems were subjected to a mechanical treatment process for the extraction of bamboo fiber bundles. The fiber bundles were used as reinforcement for the fabrication of high-performance composites with phenolic resins as matrix. The influence of fabricated density and bamboo species on physical–mechanical properties of bamboo fiber bundle reinforced composites (...

Design and analysis of a novel latch system implementing fiber-reinforced composite materials

NASA Astrophysics Data System (ADS)

Guevara Arreola, Francisco Javier

The use of fiber-reinforced composite materials have increased in the last four decades in high technology applications due to their exceptional mechanical properties and low weight. In the automotive industry carbon fiber have become popular exclusively in luxury cars because of its high cost. However, Carbon-glass hybrid composites offer an effective alternative to designers to implement fiber-reinforced composites into several conventional applications without a considerable price increase maintaining most of their mechanical properties. A door latch system is a complex mechanism that is under high loading conditions during car accidents such as side impacts and rollovers. Therefore, the Department of Transportation in The United States developed a series of tests that every door latch system comply in order to be installed in a vehicle. The implementation of fiber-reinforced composite materials in a door latch system was studied by analyzing the material behavior during the FMVSS No. 206 transverse test using computational efforts and experimental testing. Firstly, a computational model of the current forkbolt and detent structure was developed. Several efforts were conducted in order to create an effective and time efficient model. Two simplified models were implemented with two different contact interaction approaches. 9 composite materials were studied in forkbolt and 5 in detent including woven carbon fiber, unidirectional carbon fiber, woven carbon-glass fiber hybrid composites and unidirectional carbon-glass fiber hybrid composites. The computational model results showed that woven fiber-reinforced composite materials were stiffer than the unidirectional fiber-reinforced composite materials. For instance, a forkbolt made of woven carbon fibers was 20% stiffer than a forkbolt made of unidirectional fibers symmetrically stacked in 0° and 90° alternating directions. Furthermore, Hybrid composite materials behaved as expected in forkbolt noticing a decline

New knitted fabric concepts for denim products

NASA Astrophysics Data System (ADS)

Marmaralı, A.; Ertekin, G.; Oğlakcıoğlu, N.; Kertmen, M.; Seçil Aydın, İ.

2017-10-01

“Denim” like knitted fabric is a new trend combining the appearance of woven denim with the knitted structures’ characteristics such as flexibility, softness, wrinkle resistance, user-friendliness, and comfortable. According to the requirements of markets, it can be obviously seen that, this fabric will be a new era for denim industry which can be competitive with woven denim garments. This study presents general information and literature survey about denim production, knitted denim structures and their characteristics.

Effect of Reinforcement Using Stainless Steel Mesh, Glass Fibers, and Polyethylene on the Impact Strength of Heat Cure Denture Base Resin - An In Vitro Study

PubMed Central

Murthy, H B Mallikarjuna; Shaik, Sharaz; Sachdeva, Harleen; Khare, Sumit; Haralur, Satheesh B; Roopa, K T

2015-01-01

Background: The impact strength of denture base resin is of great concern and many approaches have been made to strengthen acrylic resin dentures. The objective of this study was to compare the impact strength of the denture base resin with and without reinforcement and to evaluate the impact strength of denture base resin when reinforced with stainless steel mesh, glass fiber, and polyethylene fibers in the woven form. Materials and Methods: The specimens (maxillary denture bases) were fabricated using a standard polyvinylsiloxane mold with conventional heat cured polymethyl methacrylate resin. The specimens were divided into four groups (n = 10). Group I specimens or control group were not reinforced. Group II specimens were reinforced with stainless steel mesh and Group III and Group IV specimens were reinforced with three percent by weight of glass fibers and polyethylene fibers in weave form respectively. All the specimens were immersed in water for 1-week before testing. The impact strength was measured with falling weight impact testing machine. One-way analysis of variance and Tukey’s post-hoc test were used for statistical analysis. Results: Highest impact strength values were exhibited by the specimens reinforced with polyethylene fibers followed by glass fibers, stainless steel mesh, and control group. Conclusions: Reinforcement of maxillary complete dentures showed a significant increase in impact strength when compared to unreinforced dentures. Polyethylene fibers exhibit better impact strength followed by glass fibers and stainless steel mesh. By using pre-impregnated glass and polyethylene fibers in woven form (prepregs) the impact strength of the denture bases can be increased effectively. PMID:26124604

Effect of Reinforcement Using Stainless Steel Mesh, Glass Fibers, and Polyethylene on the Impact Strength of Heat Cure Denture Base Resin - An In Vitro Study.

PubMed

Murthy, H B Mallikarjuna; Shaik, Sharaz; Sachdeva, Harleen; Khare, Sumit; Haralur, Satheesh B; Roopa, K T

2015-06-01

The impact strength of denture base resin is of great concern and many approaches have been made to strengthen acrylic resin dentures. The objective of this study was to compare the impact strength of the denture base resin with and without reinforcement and to evaluate the impact strength of denture base resin when reinforced with stainless steel mesh, glass fiber, and polyethylene fibers in the woven form. The specimens (maxillary denture bases) were fabricated using a standard polyvinylsiloxane mold with conventional heat cured polymethyl methacrylate resin. The specimens were divided into four groups (n = 10). Group I specimens or control group were not reinforced. Group II specimens were reinforced with stainless steel mesh and Group III and Group IV specimens were reinforced with three percent by weight of glass fibers and polyethylene fibers in weave form respectively. All the specimens were immersed in water for 1-week before testing. The impact strength was measured with falling weight impact testing machine. One-way analysis of variance and Tukey's post-hoc test were used for statistical analysis. Highest impact strength values were exhibited by the specimens reinforced with polyethylene fibers followed by glass fibers, stainless steel mesh, and control group. Reinforcement of maxillary complete dentures showed a significant increase in impact strength when compared to unreinforced dentures. Polyethylene fibers exhibit better impact strength followed by glass fibers and stainless steel mesh. By using pre-impregnated glass and polyethylene fibers in woven form (prepregs) the impact strength of the denture bases can be increased effectively.

Microfibrous β-TCP/collagen scaffolds mimic woven bone in structure and composition.

PubMed

Zhang, Shen; Zhang, Xin; Cai, Qing; Wang, Bo; Deng, Xuliang; Yang, Xiaoping

2010-12-01

Woven bone, as the initial form of bone tissue, is always found in developing and repairing bone. It is thought of as a temporary scaffold for the deposition of osteogenic cells and the laying down of lamellar bone. Thus, we hypothesize that a matrix which resembles the architecture and components of woven bone can provide an osteoblastic microenvironment for bone cell growth and new bone formation. In this study, woven-bone-like beta-tricalcium phosphate (β-TCP)/collagen scaffolds were fabricated by sol-gel electrospinning and impregnating methods. Optimization studies on sol-gel synthesis and electrospinning process were conducted respectively to prepare pure β-TCP fibers with dimensions close to mineralized collagen fibrils in woven bone. The collagen-coating layer prepared by impregnation had an adhesive role that held the β-TCP fibers together, and resulted in rapid degradation and matrix mineralization in in vitro tests. MG63 osteoblast-like cells seeded on the resultant scaffolds showed three-dimensional (3D) morphologies, and merged into multicellular layers after 7 days culture. Cytotoxicity test further revealed that extracts from the resultant scaffolds could promote the proliferation of MG63 cells. Therefore, the woven-bone-like matrix that we constructed favored the attachment and proliferation of MG63 cells in three dimensions. It has great potential ability to shorten the time of formation of new bone.

Low Cost Fabrication of Silicon Carbide Based Ceramics and Fiber Reinforced Composites

NASA Technical Reports Server (NTRS)

Singh, M.; Levine, S. R.

1995-01-01

A low cost processing technique called reaction forming for the fabrication of near-net and complex shaped components of silicon carbide based ceramics and composites is presented. This process consists of the production of a microporous carbon preform and subsequent infiltration with liquid silicon or silicon-refractory metal alloys. The microporous preforms are made by the pyrolysis of a polymerized resin mixture with very good control of pore volume and pore size thereby yielding materials with tailorable microstructure and composition. Mechanical properties (elastic modulus, flexural strength, and fracture toughness) of reaction-formed silicon carbide ceramics are presented. This processing approach is suitable for various kinds of reinforcements such as whiskers, particulates, fibers (tows, weaves, and filaments), and 3-D architectures. This approach has also been used to fabricate continuous silicon carbide fiber reinforced ceramic composites (CFCC's) with silicon carbide based matrices. Strong and tough composites with tailorable matrix microstructure and composition have been obtained. Microstructure and thermomechanical properties of a silicon carbide (SCS-6) fiber reinforced reaction-formed silicon carbide matrix composites are discussed.

Dynamic mechanical analysis and high strain-rate energy absorption characteristics of vertically aligned carbon nanotube reinforced woven fiber-glass composites

USDA-ARS?s Scientific Manuscript database

The dynamic mechanical behavior and energy absorption characteristics of nano-enhanced functionally graded composites, consisting of 3 layers of vertically aligned carbon nanotube (VACNT) forests grown on woven fiber-glass (FG) layer and embedded within 10 layers of woven FG, with polyester (PE) and...

The effect of woven roving fiberglass total layers on resin infusion time in vacuum infusion

NASA Astrophysics Data System (ADS)

Saputra, A. H.; Ibrahim, R. H.

2018-04-01

Composite material consists of reinforcement materials and resin as a matrix. Vacuum infusion isone of composite material manufacturing process. This process is to minimize the air cavity on composite material. The composite material will have good mechanical properties. There is a problem in vacuum infusion related to resin gelling time that must be considered. In this study, the area as well as the reinforcement layers are variated. Unsaturated polyester was used as resin and woven roving fiberglass was used as reinforcement. This study was obtained that resin infusion time data for woven roving, 15x20 cm of size, in two until six layers are 55 seconds to 78 seconds; whereas, the infusion times for 15x25 cm of size,in two until six layers are 119 seconds to 235 seconds; whereas the infusion time for 15x35 cm of size, in two until six layers are 181 seconds to 303 seconds. By data processing, the maximum fiber area that resin still can flow, for 6 layers, is 0,4391 m2 (or 15 cm x 2.92m). Maximum fiber total layers for the specimen with 15x20cm2, 15x25cm2 and 15x35 cm2 of areaare 147, 145 and 125 layers respectively.

Characterization of impact damage in woven fiber composites using fiber Bragg grating sensing and NDE

NASA Astrophysics Data System (ADS)

Hiche, Cristobal; Liu, Kuang C.; Seaver, Mark; Wei, Jun; Chattopadhyay, Aditi

2009-03-01

Woven fiber composites are currently being investigated due to their advantages over other materials, making them suitable for low weight, high stiffness, and high interlaminar fracture toughness applications such as missiles, body armor, satellites, and many other aerospace applications. Damage characterization of woven fabrics is a complex task due to their tendency to exhibit different failure modes based on the weave configuration, orientation, ply stacking and other variables. A multiscale model is necessary to accurately predict progressive damage. The present research is an experimental study on damage characterization of three different woven fiber laminates under low energy impact using Fiber Bragg Grating (FBG) sensors and flash thermography. A correlation between the measured strain from FBG sensors and the damaged area obtained from flash thermography imaging has been developed. It was observed that the peak strain in the fabrics were strongly dependent on the weave geometry and decreased at different rates as damage area increased due to dissimilar failure modes. Experimental observations were validated with the development of a multiscale model. A FBG sensor placement model was developed which showed that FBG sensor location and orientation plays a key role in the sensing capabilities of strain on the samples.

Control of reflection cracking in a fabric-reinforced overlay on jointed portland cement concrete pavement.

DOT National Transportation Integrated Search

1982-01-01

A study of the installation and three-year performance evaluation of a fabric-reinforced bituminous concrete overlay of a jointed concrete pavement is reported. The fabric, a polypropylene in an asphaltic mastic, was shown to act as a significant det...

Comparative evaluation of woven graphite-epoxy composites

NASA Technical Reports Server (NTRS)

Hanagud, S.; Tayebi, A.; Clinton, R. G., Jr.; Nayak, B. M.

1979-01-01

A comparative evaluation of some of the mechanical properties of woven graphite-epoxy composites are discussed. In particular, the types of weaves and the resin contents were chosen for comparison. The types of weaves selected are plain weave, satin weave, and tridirectional weave. The composites made of the fabrics are compared to composites made from unidirectional tapes under static and fatigue loading. During static loading, acoustic emission events were monitored. Also, examinations of fracture surfaces and polished sections both away from the fracture surface, and of virgin specimens under an electron microscope are discussed.

The Effect of Temperature and Nanoclay on the Low Velocity and Ballistic Behavior of Woven Glass-Fiber Reinforced Composites

NASA Astrophysics Data System (ADS)

Patrin, Lauren

The objective of this research was to study the effect of nanoclay and temperature on the behavior of woven glass-fabric reinforced epoxy composite under low velocity and ballistic impacts. The materials used in manufacturing the composite were S2 (6181) glass-fibers, epoxy resin (EPON 828), hardener (Epikure 3230), nanoclay and Heloxy 61 modifier. The nanoclay addition was 0%, 1%, 3% and 5% by weight, with respect to the resin. All specimens were manufactured at the City College facilities using vacuum infusion. Tensile tests were conducted to characterize the material and obtain the Young's modulus, ultimate stress, failure strain, Poisson's ratio, shear modulus and shear strength and their variation with nanoclay percentage and temperature. The tests were conducted at room temperature (21°C/70°F), -54°C (-65°F), -20°C (-4°F), 49°C (120°F) and 71°C (160°F). Next composite specimens with 0%, 1%, 3% and 5% nanoclay by weight, with respect to the resin, were subjected to low velocity impact at the previously specified temperatures to determine dynamic force, displacement and energy correlations. The extent of damage was studied using the ultrasound technique. Then ballistic tests were conducted on the nanoclay infused specimens at room temperature to obtain the ballistic limit (V50) and the damage behavior of the composite. The dynamic finite element analysis (FEA) software LS-DYNA was used to model and simulate the results of low velocity impact tests. Good agreement was obtained between experimental and numerical (FEA) results. Analytical analyses were undertaken to compare the results from the tensile experiments. The finite element analysis (FEA) allowed for further analytical comparison of the results. The FEA platform used was LS-DYNA due to its proficient dynamic and damage capabilities in composite materials. The FEA was used to model and simulate the low velocity impacts and compare the results to experiments.

In vivo testing of a biodegradable woven fabric made of bioactive glass fibers and PLGA80--a pilot study in the rabbit.

PubMed

Alm, Jessica J; Frantzén, Janek P A; Moritz, Niko; Lankinen, Petteri; Tukiainen, Mikko; Kellomäki, Minna; Aro, Hannu T

2010-05-01

The purpose of this study was to perform an intra-animal comparison of biodegradable woven fabrics made of bioactive glass (BG) fibers and poly(L-lactide-co-glycolide) 80/20 copolymer (PLGA(80)) fibers or PLGA(80) fibers alone, in surgical stabilization of bone graft. The BG fibers (BG 1-98) were aimed to enhance bone growth at site of bone grafting, whereas the PLGA component was intended to provide structural strength and flexibility to the fabric. Bone formation was analyzed qualitatively by histology and quantitatively by peripheral quantitative computed tomography (pQCT) at 12 weeks. The surgical handling properties of the control PLGA(80) fabric were more favorable. Both fabrics were integrated with the cortical bone surfaces, but BG fibers showed almost complete resorption. There were no signs of adverse local tissue reactions. As a proof of material integration and induced new bone formation, there was a significant increase in bone volume of the operated femurs compared with the contralateral intact bone (25% with BG/PLGA(80) fabric, p < 0.001 and 28% with the control PLGA(80) fabric, p = 0.006). This study failed to demonstrate the previously seen positive effect of BG 1-98 on osteogenesis, probably due to the changed resorption properties of BG in the form of fibers. Therefore, the feasibility and safety of BG as fibers needs to be reevaluated before use in clinical applications. (c) 2010 Wiley Periodicals, Inc.

The Fabric of the Universe: Exploring the Cosmic Web in 3D Prints and Woven Textiles

NASA Astrophysics Data System (ADS)

Diemer, Benedikt; Facio, Isaac

2017-05-01

We introduce The Fabric of the Universe, an art and science collaboration focused on exploring the cosmic web of dark matter with unconventional techniques and materials. We discuss two of our projects in detail. First, we describe a pipeline for translating three-dimensional (3D) density structures from N-body simulations into solid surfaces suitable for 3D printing, and present prints of a cosmological volume and of the infall region around a massive cluster halo. In these models, we discover wall-like features that are invisible in two-dimensional projections. Going beyond the sheer visualization of simulation data, we undertake an exploration of the cosmic web as a three-dimensional woven textile. To this end, we develop experimental 3D weaving techniques to create sphere-like and filamentary shapes and radically simplify a region of the cosmic web into a set of filaments and halos. We translate the resulting tree structure into a series of commands that can be executed by a digital weaving machine, and present a large-scale textile installation.

Microtensile Test of AN Ordered-Reinforced Electrophoretic Polymer Matrix Composite Fabricated by Surface Micromachining

NASA Astrophysics Data System (ADS)

Yang, Zhuoqing; Wang, Hong; Zhang, Zhenjie; Ding, Guifu; Zhao, Xiaolin

A novel ordered-reinforced microscale polymer matrix composite based on electrophoresis and surface micromachining technologies has been proposed in the present work. The braid angle, volume content and width of the reinforcement in the composite has been designed and simulated by ANSYS finite element software. Based on the simulation and optimization, the Ni fibers reinforced polymer matrix composite sample (3 mm length × 0.6 mm width × 0.04 mm thickness) was successfully fabricated utilizing the surface micromachining process. The fabricated samples were characterized by microtensile test on the dynamic mechanical analysis (DMA) equipment. It is indicated that the tested tensile strength and Young's modulus are 285 MPa and 6.8 GPa, respectively. In addition, the fracture section of the composite sample has been observed by scanning electron microscope (SEM) and the corresponding fracture process was also explained and analyzed in detail. The new presented composite is promising for hot embossing mold in microfluidic chip and several transducers used in accurately controlled biomedical systems.

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

25 CFR 307.4 - Standards for fabrics.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false Standards for fabrics. 307.4 Section 307.4 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO ALL-WOOL WOVEN FABRICS; USE OF GOVERNMENT CERTIFICATE OF GENUINENESS § 307.4 Standards for fabrics. No fabric may carry the Government certificate of...

Fabrication of nanofibers reinforced polymer microstructures using femtosecond laser material processing

NASA Astrophysics Data System (ADS)

Alubaidy, Mohammed-Amin

A new method has been introduced for the formation of microfeatures made of nanofibers reinforced polymer, using femtosecond laser material processing. The Femtosecond laser is used for the generation of three-dimensional interweaved nanofibers and the construction of microfeatures, like microchannels and voxels, through multi photon polymerization of nanofiber dispersed polymer resin. A new phenomenon of multiphoton polymerization induced by dual wavelength irradiation was reported for the first time. A significant improvement in the spatial resolution, compared to the two photon absorption (2PA) and the three photon absorption (3PA) processes has been achieved. Conductive polymer microstructures and magnetic polymer microstructures have been fabricated through this method. The mechanical properties of nanofiber reinforced polymer microstructures has been investigated by means of nanoindentation and the volume fraction of the generated nanofibers in the nanocomposite was calculated by using nanoindentation analysis. The results showed significant improvement in strength of the material. The electrical conductivity of the two photon polymerization (TPP) generated microfeatures was measured by a two-probe system at room temperature and the conductivity-temperature relationship was measured at a certain temperature range. The results suggest that the conductive polymer microstructure is reproducible and has a consistent conductivity-temperature relation. The magnetic strength has been characterized using Guassmeter. To demonstrate the potential application of the new fabrication method, a novel class of DNA-functionalized three-dimensional (3D), stand-free, and nanostructured electrodes were fabricated. The developed nanofibrous DNA biosensor has been characterized by cyclic voltammetry with the use of ferrocyanide as an electrochemical redox indicator. Results showed that the probe--target recognition has been improved. This research demonstrated that femtosecond

Reversible dielectric property degradation in moisture-contaminated fiber-reinforced laminates

NASA Astrophysics Data System (ADS)

Rodriguez, Luis A.; García, Carla; Fittipaldi, Mauro; Grace, Landon R.

2016-03-01

The potential for recovery of dielectric properties of three water-contaminated fiber-reinforced laminates is investigated using a split-post dielectric resonant technique at X-band (10 GHz). The three material systems investigated are bismaleimide (BMI) reinforced with an eight-harness satin weave quartz fabric, an epoxy resin reinforced with an eight- harness satin weave glass fabric (style 7781), and the same epoxy reinforced with a four-harness woven glass fabric (style 4180). A direct correlation between moisture content, dielectric constant, and loss tangent was observed during moisture absorption by immersion in distilled water at 25 °C for five equivalent samples of each material system. This trend is observed through at least 0.72% water content by weight for all three systems. The absorption of water into the BMI, 7781 epoxy, and 4180 epoxy laminates resulted in a 4.66%, 3.35%, and 4.01% increase in dielectric constant for a 0.679%, 0.608%, and 0.719% increase in water content by weight, respectively. Likewise, a significant increase was noticed in loss tangent for each material. The same water content is responsible for a 228%, 71.4%, and 64.1% increase in loss tangent, respectively. Subsequent to full desorption through drying at elevated temperature, the dielectric constant and loss tangent of each laminate exhibited minimal change from the dry, pre-absorption state. The dielectric constant and loss tangent change after the absorption and desorption cycle, relative to the initial state, was 0.144 % and 2.63% in the BMI, 0.084% and 1.71% in the style 7781 epoxy, and 0.003% and 4.51% in the style 4180 epoxy at near-zero moisture content. The similarity of dielectric constant and loss tangent in samples prior to absorption and after desorption suggests that any chemical or morphological changes induced by the presence of water have not caused irreversible changes in the dielectric properties of the laminates.

The use of fabric reinforced overlays to control reflection cracking of composite pavements.

DOT National Transportation Integrated Search

1973-01-01

Fabric reinforcement was used in an attempt to prevent reflection cracking of two bituminous concrete layers overlying an 8-inch plain (unreinforced, unjointed) concrete base that was underlain by a portland cement stabilized subbase material. On the...

Production of Banana Fiber Yarns for Technical Textile Reinforced Composites

PubMed Central

Ortega, Zaida; Morón, Moisés; Monzón, Mario D.; Badalló, Pere; Paz, Rubén

2016-01-01

Natural fibers have been used as an alternative to synthetic ones for their greener character; banana fibers have the advantage of coming from an agricultural residue. Fibers have been extracted by mechanical means from banana tree pseudostems, as a strategy to valorize banana crops residues. To increase the mechanical properties of the composite, technical textiles can be used as reinforcement, instead of short fibers. To do so, fibers must be spun and woven. The aim of this paper is to show the viability of using banana fibers to obtain a yarn suitable to be woven, after an enzymatic treatment, which is more environmentally friendly. Extracted long fibers are cut to 50 mm length and then immersed into an enzymatic bath for their refining. Conditions of enzymatic treatment have been optimized to produce a textile grade of banana fibers, which have then been characterized. The optimum treating conditions were found with the use of Biopectinase K (100% related to fiber weight) at 45 °C, pH 4.5 for 6 h, with bath renewal after three hours. The first spinning trials show that these fibers are suitable to be used for the production of yarns. The next step is the weaving process to obtain a technical fabric for composites production. PMID:28773490

Computer Representation of Fabric Pattern Weaves as Woven Fabric Samples and Texture Maps for Educational and Industrial Applications.

ERIC Educational Resources Information Center

Murtha, Judith Rush

The purpose of this study was to write a computer program that would not only output a color pattern weave to a cathode ray tube (CRT), but would also analyze a painted design and output a printed diagram that would show how to set up a loom in order to produce the woven design. The first of seven chapters describes the problem and the intent of…

Hypervelocity Impact Experiments on Epoxy/Ultra-High Molecular Weight Polyethylene Composite Panels Reinforced with Nanotubes

NASA Technical Reports Server (NTRS)

Khatiwada, Suman; Laughman, Jay W.; Armada, Carlos A.; Christiansen, Eric L.; Barrera, Enrique V.

2012-01-01

Advanced composites with multi-functional capabilities are of great interest to the designers of aerospace structures. Polymer matrix composites (PMCs) reinforced with high strength fibers provide a lightweight and high strength alternative to metals and metal alloys conventionally used in aerospace architectures. Novel reinforcements such as nanofillers offer potential to improve the mechanical properties and add multi-functionality such as radiation resistance and sensing capabilities to the PMCs. This paper reports the hypervelocity impact (HVI) test results on ultra-high molecular weight polyethylene (UHMWPE) fiber composites reinforced with single-walled carbon nanotubes (SWCNT) and boron nitride nanotubes (BNNT). Woven UHMWPE fabrics, in addition to providing excellent impact properties and high strength, also offer radiation resistance due to inherent high hydrogen content. SWCNT have exceptional mechanical and electrical properties. BNNT (figure 1) have high neutron cross section and good mechanical properties that add multi-functionality to this system. In this project, epoxy based UHMWPE composites containing SWCNT and BNNT are assessed for their use as bumper shields and as intermediate plates in a Whipple Shield for HVI resistance. Three composite systems are prepared to compare against one another: (I) Epoxy/UHMWPE, (II) Epoxy/UHMWPE/SWCNT and (III) Epoxy/UHMWPE/SWCNT/BNNT. Each composite is a 10.0 by 10.0 by 0.11 cm3 panel, consisting of 4 layers of fabrics arranged in cross-ply orientation. Both SWCNT and BNNT are 0.5 weight % of the fabric preform. Hypervelocity impact tests are performed using a two-stage light gas gun at Rice University

75 FR 53711 - Narrow Woven Ribbons With Woven Selvedge From China and Taiwan

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-01

... Woven Ribbons With Woven Selvedge From China and Taiwan Determinations On the basis of the record \\1... U.S.C. 1673d(b)) (the Act), that an industry in the United States is threatened with material injury... (19 U.S.C. 1673d(b)), that an industry in the United States is threatened with material injury by...

AN EMPIRICAL MODEL TO PREDICT STYRENE EMISSIONS FROM FIBER-REINFORCED PLASTICS FABRICATION PROCESSES

EPA Science Inventory

Styrene is a designated hazardous air pollutant, per the 1990 Clean Air Act Amendments. It is also a tropospheric ozone precursor. Fiber-reinforced plastics (FRP) fabrication is the primary source of anthropogenic styrene emissions in the United States. This paper describes an em...

The role of rapid solidification processing in the fabrication of fiber reinforced metal matrix composites

NASA Technical Reports Server (NTRS)

Locci, Ivan E.; Noebe, Ronald D.

1989-01-01

Advanced composite processing techniques for fiber reinforced metal matrix composites require the flexibility to meet several widespread objectives. The development of uniquely desired matrix microstructures and uniformly arrayed fiber spacing with sufficient bonding between fiber and matrix to transmit load between them without degradation to the fiber or matrix are the minimum requirements necessary of any fabrication process. For most applications these criteria can be met by fabricating composite monotapes which are then consolidated into composite panels or more complicated components such as fiber reinforced turbine blades. Regardless of the end component, composite monotapes are the building blocks from which near net shape composite structures can be formed. The most common methods for forming composite monotapes are the powder cloth, foil/fiber, plasma spray, and arc spray processes. These practices, however, employ rapid solidification techniques in processing of the composite matrix phase. Consequently, rapid solidification processes play a vital and yet generally overlooked role in composite fabrication. The future potential of rapid solidification processing is discussed.

Coated woven materials and method of preparation

DOEpatents

McCreary, William J.; Carroll, David W.

1981-01-01

Coating of woven materials so that not only the outer surfaces are coated has been a problem. Now, a solution to that problem is the following: Woven materials are coated with materials, for example with metals or with pyrolytic carbon, which materials are deposited in Chemical Vapor Deposition (CVD) reactions using a fluidized bed so that the porosity of the woven material is retained and so that the tiny filaments which make up the strands which are woven (including inner as well as outer filaments) are substantially uniformly coated.

Strengthening the Fabric of Government: A Description of WOVEN (Women's Ohio Volunteer Employment Network).

ERIC Educational Resources Information Center

Miller, Mary E.

WOVEN (Women's Ohio Volunteer Employment Network), is directed at changing the low representation of women in decision making positions in public service. Women comprise more than a third of the work force in the State of Ohio; yet they have typically held the low level, low paying jobs. A 1973 status report on women in State government revealed…

Experimental Characterization and Micromechanical Modeling of Woven Carbon/Copper Composites

NASA Technical Reports Server (NTRS)

Bednarcyk, Brett A.; Pauly, Christopher C.; Pindera, Marek-Jerzy

1997-01-01

The results of an extensive experimental characterization and a preliminary analytical modeling effort for the elastoplastic mechanical behavior of 8-harness satin weave carbon/copper (C/Cu) composites are presented. Previous experimental and modeling investigations of woven composites are discussed, as is the evolution of, and motivation for, the continuing research on C/Cu composites. Experimental results of monotonic and cyclic tension, compression, and Iosipescu shear tests, and combined tension-compression tests, are presented. With regard to the test results, emphasis is placed on the effect of strain gauge size and placement, the effect of alloying the copper matrix to improve fiber-matrix bonding, yield surface characterization, and failure mechanisms. The analytical methodology used in this investigation consists of an extension of the three-dimensional generalized method of cells (GMC-3D) micromechanics model, developed by Aboudi (1994), to include inhomogeneity and plasticity effects on the subcell level. The extension of the model allows prediction of the elastoplastic mechanical response of woven composites, as represented by a true repeating unit cell for the woven composite. The model is used to examine the effects of refining the representative geometry of the composite, altering the composite overall fiber volume fraction, changing the size and placement of the strain gauge with respect to the composite's reinforcement weave, and including porosity within the infiltrated fiber yarns on the in-plane elastoplastic tensile, compressive, and shear response of 8-harness satin C/Cu. The model predictions are also compared with the appropriate monotonic experimental results.

Fabrication of Zirconia-Reinforced Lithium Silicate Ceramic Restorations Using a Complete Digital Workflow

PubMed Central

Rödiger, Matthias; Ziebolz, Dirk; Schmidt, Anne-Kathrin

2015-01-01

This case report describes the fabrication of monolithic all-ceramic restorations using zirconia-reinforced lithium silicate (ZLS) ceramics. The use of powder-free intraoral scanner, generative fabrication technology of the working model, and CAD/CAM of the restorations in the dental laboratory allows a completely digitized workflow. The newly introduced ZLS ceramics offer a unique combination of fracture strength (>420 MPa), excellent optical properties, and optimum polishing characteristics, thus making them an interesting material option for monolithic restorations in the digital workflow. PMID:26509088

Constituent Effects on the Stress-Strain Behavior of Woven Melt-Infiltrated SiC Composites

NASA Technical Reports Server (NTRS)

Morscher, Gregory N.; Eldridge, Jeff I.; Levine, Stanley (Technical Monitor)

2001-01-01

The stress-strain behavior of 2D woven SiC fiber reinforced, melt-infiltrated SiC matrix composites with BN interphases were studied for composites fabricated with different fiber tow ends per unit length, different composite thickness, and different numbers of plies. In general, the stress-strain behavior, i.e., the 'knee' in the curve and the final slope of the stress-strain curve, was controlled by the volume fraction of fibers. Some of the composites exhibited debonding and sliding in between the interphase and the matrix rather than the more common debonding and sliding interface between the fiber and the interphase. Composites that exhibited this 'outside debonding' interface, in general, had lower elastic moduli and higher ultimate strains as well as longer pull-out lengths compared to the 'inside debonding' interface composites. Stress-strain curves were modeled where matrix crack formation as a function of stress was approximated from the acoustic emission activity and the measured crack density from the failed specimens. Interfacial shear strength measurements from individual fiber push-in tests were in good agreement with the interfacial shear strength values used to model the stress-strain curves.

The construction phase’s influence to the moving ability of cross-sections of woven structure

NASA Astrophysics Data System (ADS)

Inogamdjanov, D.; Daminov, A.; Kasimov, O.

2017-10-01

The purpose of this study is to work out bases to predict properties for single layer flat woven fabrics depending on changes of construction phases. A structural model of cross-section of single layered fabric is described based on the Pierce’s model. Form transformation of the yarn like straight, semi-arch and arch yarn is considered according to the alteration of yarn tension under the theory of Novikov. The value contributions to movement index of warp and weft yarn and their total moving ability in cross-sections at all structure phases of fabric are summarized.

Design and Fabrication of Graphene Reinforced Polymer Conductive Patch-Based Inset Fed Microstrip Antenna

NASA Astrophysics Data System (ADS)

Deepak, A.; Kannan, P. Muthu; Shankar, P.

This work explores the design and fabrication of graphene reinforced polyvinylidene fluoride (PVDF) patch-based microstrip antenna. Primarily, antenna was designed at 6GHz frequency and simulation results were obtained using Ansoft HFSS tool. Later fabrication of antenna was carried out with graphene-PVDF films as conducting patch deposited on bakelite substrate and copper as ground plane. Graphene-PVDF films were prepared using solvent casting process. The radiation efficiency of fabricated microstrip patch antenna was 48% entailing it to be adapted as a practically functional antenna. Both simulated and the practical results were compared and analyzed.

Damage and fracture in fabric-reinforced composites under quasi-static and dynamic bending

NASA Astrophysics Data System (ADS)

Ullah, H.; Harland, A. R.; Silberschmidt, V. V.

2013-07-01

Fabric-reinforced polymer composites used in sports products can be exposed to different in-service conditions such as large deformations caused by quasi-static and dynamic loading. Composite materials subjected to such bending loads can demonstrate various damage modes - matrix cracking, delamination and, ultimately, fabric fracture. Damage evolution in composites affects both their in-service properties and performance that can deteriorate with time. Such behaviour needs adequate means of analysis and investigation, the main approaches being experimental characterisation and non-destructive examination of internal damage in composite laminates. This research deals with a deformation behaviour and damage in carbon fabric-reinforced polymer (CFRP) laminates caused by quasi-static and dynamic bending. Experimental tests were carried out to characterise the behaviour of a CFRP material under large-deflection bending, first in quasi-static and then in dynamic conditions. Izod-type impact bending tests were performed on un-notched specimens of CFRP using a Resil impactor to assess the transient response and energy absorbing capability of the material. X-ray micro computed tomography (micro-CT) was used to analyse various damage modes in the tested specimens. X-ray tomographs revealed that through-thickness matrix cracking, inter-ply and intra-ply delamination such as tow debonding, and fabric fracture were the prominent damage modes both in quasi-static and dynamic test specimens. However, the inter-ply damage was localised at impact location in dynamically tested specimens, whereas in the quasi-static specimens, it spread almost over the entire interface.

77 FR 32938 - Narrow Woven Ribbons With Woven Selvedge From Taiwan: Preliminary Results of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-04

..., style, pattern, or weave construction, including but not limited to single-faced satin, double-faced... DEPARTMENT OF COMMERCE International Trade Administration [A-583-844] Narrow Woven Ribbons With Woven Selvedge From Taiwan: Preliminary Results of Antidumping Duty Administrative Review AGENCY: Import...

Modeling of process-induced residual stresses and resin flow behavior in resin transfer molded composites with woven fiber mats

NASA Astrophysics Data System (ADS)

Golestanian, Hossein

This research focuses on modeling Resin Transfer Molding process for manufacture of composite parts with woven fiber mats. Models are developed to determine cure dependent stiffness matrices for composites manufactured with two types of woven fiber mats. Five-harness carbon and eight-harness fiberglass mats with EPON 826 resin composites are considered. The models presented here take into account important material/process parameters with emphasis on; (1) The effects of cure-dependent resin mechanical properties, (2) Fiber undulation due to the weave of the fiber fill and warp bundles, and (3) Resin interaction with the fiber bundles at a microscopic scale. Cure-dependent mechanical properties were then used in numerical models to determine residual stresses and deformation in the composite parts. The complete cure cycle was modeled in these analyses. Also the cool down stage after the composite cure was analyzed. The effect of 5% resin shrinkage on residual stresses and deformations was also investigated. In the second part of the study, Finite Element models were developed to simulate mold filling in RTM processes. Resin flow in the fiber mats was modeled as flow through porous media. Physical models were also developed to investigate resin flow behavior into molds of rectangular and irregular shapes. Silicone fluids of 50 and 100 centistoke viscosities as well as EPON 826 epoxy resin were used in the mold filling experiments. The reinforcements consisted of several layers of woven fiberglass and carbon fiber mats. The effects of injection pressure, fluid viscosity, type of reinforcement, and mold geometry on mold filling times were investigated. Fiber mat permeabilities were determined experimentally for both types of reinforcements. Comparison of experimental and numerical resin front positions indicated the importance of edge effects in resin flow behavior in small cavities. The resin front positions agreed well for the rectangular mold geometry.

Development of glass fibre reinforced composites using microwave heating technology

NASA Astrophysics Data System (ADS)

Köhler, T.; Vonberg, K.; Gries, T.; Seide, G.

2017-10-01

Fibre reinforced composites are differentiated by the used matrix material (thermoplastic versus duroplastic matrix) and the level of impregnation. Thermoplastic matrix systems get more important due to their suitability for mass production, their good shapeability and their high impact resistance. A challenge in the processing of these materials is the reduction of the melt flow paths of the thermoplastic matrix. The viscosity of molten thermoplastic material is distinctly higher than the viscosity of duroplastic material. An approach to reduce the flow paths of the thermoplastic melt is given by a commingling process. Composites made from commingling hybrid yarns consist of thermoplastic and reinforcing fibres. Fabrics made from these hybrid yarns are heated and consolidated by the use of heat pressing to form so called organic sheets. An innovative heating system is given by microwaves. The advantage of microwave heating is the volumetric heating of the material, where the energy of the electromagnetic radiation is converted into thermal energy inside the material. In this research project microwave active hybrid yarns are produced and examined at the Institute for Textile Technology of RWTH Aachen University (ITA). The industrial research partner Fricke und Mallah Microwave Technology GmbH, Peine, Germany develops an innovative pressing systems based on a microwave heating system. By implementing the designed microwave heating technology into an existing heat pressing process, FRTCs are being manufactured from glass and nanomodified polypropylene fibre woven fabrics. In this paper the composites are investigated for their mechanical and optical properties.

Polymer Composite Wrapping and Cathodic Protection System for Reinforced Concrete Piles in Marine Applications

DTIC Science & Technology

2013-06-01

vicinity of new patches. Fiber -reinforced polymer (FRP) composite wrapping systems have been evolving over the last 20 years and are now a viable...material is a woven glass fiber pre-impregnated with moisture-activated resins that cure underwater after being put in place. Figure 4. ICPW...wrap system The FRP composite wrap material that was selected is Aqua Wrap Type G- 05, a woven glass fiber pre-impregnated with moisture-activated

Systematic investigation of drip stains on apparel fabrics: The effects of prior-laundering, fibre content and fabric structure on final stain appearance.

PubMed

de Castro, Therese C; Taylor, Michael C; Kieser, Jules A; Carr, Debra J; Duncan, W

2015-05-01

Bloodstain pattern analysis is the investigation of blood deposited at crime scenes and the interpretation of that pattern. The surface that the blood gets deposited onto could distort the appearance of the bloodstain. The interaction of blood and apparel fabrics is in its infancy, but the interaction of liquids and apparel fabrics has been well documented and investigated in the field of textile science (e.g. the processes of wetting and wicking of fluids on fibres, yarns and fabrics). A systematic study on the final appearance of drip stains on torso apparel fabrics (100% cotton plain woven, 100% polyester plain woven, blend of polyester and cotton plain woven and 100% cotton single jersey knit) that had been laundered for six, 26 and 52 cycles prior to testing was investigated in the paper. The relationship between drop velocity (1.66±0.50m/s, 4.07±0.03m/s, 5.34±0.18m/s) and the stain characteristics (parent stain area, axes 1 and 2 and number of satellite stains) for each fabric was examined using analysis of variance. The experimental design and effect of storing blood were investigated on a reference sample, which indicated that the day (up to five days) at which the drops were generated did not affect the bloodstain. The effect of prior-laundering (six, 26 and 52 laundering cycles), fibre content (cotton vs. polyester vs. blend) and fabric structure (plain woven vs. single jersey knit) on the final appearance of the bloodstain were investigated. Distortion in the bloodstains produced on non-laundered fabrics indicated the importance of laundering fabrics to remove finishing treatments before conducting bloodstain experiments. For laundered fabrics, both the cotton fabrics and the blend had a circular to oval stain appearance, while the polyester fabric had a circular appearance with evidence of spread along the warp and weft yarns, which resulted in square-like stains at the lowest drop velocity. A significant (p<0.001) increase in the stain size on

Improved Fabrication of Ceramic Matrix Composite/Foam Core Integrated Structures

NASA Technical Reports Server (NTRS)

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

Apparatus and process for freeform fabrication of composite reinforcement preforms

NASA Technical Reports Server (NTRS)

Yang, Junsheng (Inventor); Wu, Liangwei (Inventor); Liu, Junhai (Inventor); Jang, Bor Z. (Inventor)

2001-01-01

A solid freeform fabrication process and apparatus for making a three-dimensional reinforcement shape. The process comprises the steps of (1) operating a multiple-channel material deposition device for dispensing a liquid adhesive composition and selected reinforcement materials at predetermined proportions onto a work surface; (2) during the material deposition process, moving the deposition device and the work surface relative to each other in an X-Y plane defined by first and second directions and in a Z direction orthogonal to the X-Y plane so that the materials are deposited to form a first layer of the shape; (3) repeating these steps to deposit multiple layers for forming a three-dimensional preform shape; and (4) periodically hardening the adhesive to rigidize individual layers of the preform. These steps are preferably executed under the control of a computer system by taking additional steps of (5) creating a geometry of the shape on the computer with the geometry including a plurality of segments defining the preform shape and each segment being preferably coded with a reinforcement composition defining a specific proportion of different reinforcement materials; (6) generating programmed signals corresponding to each of the segments in a predetermined sequence; and (7) moving the deposition device and the work surface relative to each other in response to these programmed signals. Preferably, the system is also operated to generate a support structure for any un-supported feature of the 3-D preform shape.

High strength yttria-reinforced HA scaffolds fabricated via honeycomb ceramic extrusion.

PubMed

Elbadawi, M; Shbeh, M

2018-01-01

The present study investigated the effects of hydroxyapatite (HA) reinforced with yttria on porous scaffolds fabricated via honeycomb ceramic extrusion. Yttria was selected as it has been demonstrated to toughen other ceramics. Moreover, yttria has been surmised to suppress dehydroxylation in HA, a characteristic that prefigures decomposition thereof during sintering into mechanically weaker phases. However, the compressive strength of yttria-reinforced hydroxyapatite (Y-HA) porous scaffolds has hitherto not been reported. Y-HA was synthesised by calcining a commercially available HA with 10wt% yttria at 1000°C. Y-HA was then fabricated into porous scaffolds using an in-house honeycomb extruder, and subsequently sintered at 1200 and 1250°C. The results were compared to the uncalcined as-received commercial powder (AR-HA) and calcined pure HA powder at 1000°C (C-HA). It was discovered that calcination alone caused marked improvements to the stoichiometry, thermal stability, porosity and compressive strength of scaffolds. The improvements were ascribed to the calcined powders with less susceptibility to both agglomeration and enhanced densification. Still, differences were observed between C-HA and Y-HA at 1250°C. The compressive strength increased from 105.9 to 127.3MPa, a larger microporosity was descried and the HA matrix in Y-HA was more stoichiometric. The latter was confirmed by XRD and EDS analyses. Therefore, it was concluded that the reinforcing of hydroxyapatite with yttria improved the compressive strength and suppressed dehydroxylation of porous HA scaffolds. In addition, the compressive strength achieved demonstrated great potential for load-bearing application. Copyright © 2017 Elsevier Ltd. All rights reserved.

49 CFR 178.518 - Standards for woven plastic bags.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Standards for woven plastic bags. 178.518 Section...-bulk Performance-Oriented Packaging Standards § 178.518 Standards for woven plastic bags. (a) The following are identification codes for woven plastic bags: (1) 5H1 for an unlined or non-coated woven...

49 CFR 178.518 - Standards for woven plastic bags.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Standards for woven plastic bags. 178.518 Section...-bulk Performance-Oriented Packaging Standards § 178.518 Standards for woven plastic bags. (a) The following are identification codes for woven plastic bags: (1) 5H1 for an unlined or non-coated woven...

49 CFR 178.518 - Standards for woven plastic bags.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Standards for woven plastic bags. 178.518 Section...-bulk Performance-Oriented Packaging Standards § 178.518 Standards for woven plastic bags. (a) The following are identification codes for woven plastic bags: (1) 5H1 for an unlined or non-coated woven...

Study of the indoor decontamination using nanocoated woven polyester fabric

NASA Astrophysics Data System (ADS)

Memon, Hafeezullah; Kumari, Naveeta; Jatoi, Abdul Wahab; Khoso, Nazakat Ali

2017-11-01

This research primarily deals with the photocatalytic degradation of methanol in indoor air using nanocoated indoor textiles used for curtains as household textiles. The woven polyester was coated by titanium dioxide by sol gel method, using silicon-based binder. The characterization of the coating has been done using scanning electron microscopy (SEM) image analysis, energy dispersive analysis using X-ray (EDAX) and Fourier transform infrared spectroscopy (FTIR). The DIY instrument providing the similar environment as of indoor was designed to assess the performance of the degradation of formaldehyde under UV light. The photocatalytic degradation rate was measured using the absorption value of the solutions obtained in the result of liquid chromatography of test solution and reagent solution. Different amount of dosages (1-3 %) and different time period of coatings (half hour to 3 h) have been evaluated for optimization.

Dielectric Properties of Polymer Matrix Composites Prepared from Conductive Polymer Treated Fabrics

DTIC Science & Technology

1992-02-01

JPS 09827 finish. The doping agent used was anthraquinone-2 sulfonic acid. (3) A 5 x 5 S2-glass 24 oz. woven roving with an Owens Corning 463 finish...x- I S2-glass 27 oz. woven roving with an Owens Corning 933 finish, nominally equiv- alent to the JPS 09827 finish. The doping agent used was...were fabricated by laminating the layers of Fabric with wet polyester resin ( Owens Corning E-780) and subsequently processing the com- posites using the

Dynamic Shock Response of an S2 Glass/SC15 Epoxy Woven Fabric Composite Material System

NASA Astrophysics Data System (ADS)

Key, Christopher; Alexander, Scott; Harstad, Eric; Schumacher, Shane

2017-06-01

The use of S2 glass/SC15 epoxy woven fabric composite materials for blast and ballistic protection has been an area of on-going research over the past decade. In order to accurately model this material system within potential applications under extreme loading conditions, a well characterized and well understood anisotropic equation of state (EOS) is needed. This work details both an experimental program and associated analytical modelling efforts which aim to provide better physical understanding of the anisotropic EOS behavior of this material. Experimental testing focused on planar shock impact tests loading the composite to peak pressures of 15 GPa in both the through-thickness and on-fiber orientation. Test results highlighted the anisotropic response of the material and provided a basis by which the associated numeric micromechanical investigation was compared. Results of the combined experimental and numerical modelling investigation provided insights into not only the constituent material influence on the composite response but also the importance of the geometrical configuration of the plain weave microstructure and the stochastic significance of the microstructural configuration. Sandia National Laboratories is a multi-mission laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin company, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Evaluation Report of the Double Wall Air Inflated MUST Shelter Made from Three Dimensional Fabric

DTIC Science & Technology

1975-10-22

II Natick laboratory Test Results on Spray Coated 3-D Woven Fabric iWST Shelter Casing Material ......... 29 11 3-D Casing Fabric D1mensions, as Woven...of yarns shoi . be achieved before spraying. 3.1.3 The casing surface should be inspected afhir each of the first several spray coats for pinholes in...Coated Fabric Casing Material After two days of drying time, a three-foot-wide portion was cut off from one end of a sprayed casing . Part of this coated

Axial compression behaviour of reinforced wallettes fabricated using wood-wool cement panel

NASA Astrophysics Data System (ADS)

Noh, M. S. Md; Kamarudin, A. F.; Mokhatar, S. N.; Jaudin, A. R.; Ahmad, Z.; Ibrahim, A.; Muhamad, A. A.

2018-04-01

Wood-wool cement composite panel (WWCP) is one of wood based composite material that produced in a stable panel form and suitable to be used as building wall system to replace non-ecofriendly material such as brick and other masonry element. Heavy construction material such as brick requires more manpower and consume a lot of time to build the wall panel. WWCP is a lightweight material with a density range from 300 kg/m3 to 500 kg/m3 and also capable to support an imposed load from the building. This study reported on the axial compression behaviour of prefabricated reinforced wallettes constructed with wood-wool cement panel. A total of six specimens were fabricated using two layers of cross laminated WWCP bonded with normal mortar paste (Portland cement) at a mix ratio of 1:3 (cement : sand). As part of lifting mechanism, the wallettes were equipped with three steel reinforcement (T12) that embedded inside the core of wallettes. Three replicates of wallettes specimens with dimension 600 mm width and 600 mm length were fabricated without surface plaster and with 16 mm thickness of surface plaster. The wallettes were tested under axial compression load after 28 days of fabrication until failure. The result indicated that, the application of surface plaster significantly increases the loading capacity about 35 % and different orientation of the panels improve the bonding strength of the wall.

Antibacterial activity of combination of synthetic and biopolymer non-woven structures.

PubMed

Bhullar, Sukhwinder K; Özsel, Burcak Kaya; Yadav, Ramesh; Kaur, Ginpreet; Chintamaneni, Meena; Buttar, Harpal S

2015-12-01

Fibrous structures and synthetic polymer blends offer potential usages in making biomedical devices, textiles used in medical practices, food packaging, tissue engineering, environmental applications and biomedical arena. These products are also excellent candidates for building scaffolds to grow stem cells for implantation, to make tissue engineering grafts, to make stents to open up blood vessels caused by atherosclerosis or narrowed by blood clots, for drug delivery systems for micro- to nano-medicines, for transdermal patches, and for healing of wounds and burn care. The current study was designed to evaluate the antimicrobial activity of woven and non-woven forms of nano- and macro-scale blended polymers having biocompatible and biodegradable characteristics. The antimicrobial activity of non-woven fibrous structures created with the combination of synthetic and biopolymer was assessed using Gram-negative, Gram-positive bacteria, such as Staphylococcus aureus, Proteus vulgaris, Escherichia coli and Enterobacter aerogenes using pour plate method. Structural evaluation of the fabricated samples was performed by Fourier transform infrared spectroscopy. Broad spectrum antibacterial activities were found from the tested materials consisting of polyvinyl alcohol (PVA) with chitosan and nylon-6 combined with chitosan and formic acid. The combination of PVA with chitosan was more bactericidal or bacteriostatic than that of nylon-6 combined with chitosan and formic acid. PVA combination with chitosan appears to be a broad-spectrum antimicrobial agent.

Tannin-based flax fibre reinforced composites for structural applications in vehicles

NASA Astrophysics Data System (ADS)

Zhu, J.; Abhyankar, H.; Nassiopoulos, E.; Njuguna, J.

2012-09-01

Innovation is often driven by changes in government policies regulating the industries, especially true in case of the automotive. Except weight savings, the strict EU regulation of 95% recyclable material-made vehicles drives the manufactures and scientists to seek new 'green materials' for structural applications. With handing at two major drawbacks (production cost and safety), ECHOSHELL is supported by EU to develop and optimise structural solutions for superlight electric vehicles by using bio-composites made of high-performance natural fibres and resins, providing enhanced strength and bio-degradability characteristics. Flax reinforced tannin-based composite is selected as one of the candidates and were firstly investigated with different fabric lay-up angles (non-woven flax mat, UD, [0, 90°]4 and [0, +45°, 90°, -45°]2) through authors' work. Some of the obtained results, such as tensile properties and SEM micrographs were shown in this conference paper. The UD flax reinforced composite exhibits the best tensile performance, with tensile strength and modulus of 150 MPa and 9.6 MPa, respectively. It was observed that during tension the oriented-fabric composites showed some delamination process, which are expected to be eliminated through surface treatment (alkali treatment etc.) and nanotechnology, such as the use of nano-fibrils. Failure mechanism of the tested samples were identified through SEM results, indicating that the combination of fibre pull-out, fibre breakage and brittle resins failure mainly contribute to the fracture failure of composites.

Flame-resistant pure and hybrid woven fabrics from basalt

NASA Astrophysics Data System (ADS)

Jamshaid, H.; Mishra, R.; Militky, J.

2017-10-01

This work has been formulated to investigate the burning behavior of different type of fabrics. The main concentration is to see how long the fabric resists after it catches the fire and the propagation of fire can be reduced by using flame resistant fiber i.e basalt. Basalt fiber is an environmental friendly material with low input, high output, low energy consumption and less emission. The goal of present investigations is to show the dependence of fabric flammability on its structure parameters i.e weave type, blend type etc. Fabric weaves have strong effect on flammability properties. Plain weave has the lowest burning rate as the density of the plain weave fabric is more and the structure is tight which gives less chances of flame passing through the fabric. Thermal stability is evaluated with TGA of all hybrid and nonhybrid fabrics and compared. The thermal stability of the basalt fiber is excellent. When comparing thermal analysis curves for hybrid samples it demonstrates that thermal stability of the samples containing basalt is much higher than the non- hybrid samples. Percentage weight loss is less in hybrid samples as compared to non-hybrid samples. The effectiveness of hybridization on samples may be indicated by substantial lowering of the decomposition mass. Correlation was made between flammability with the infrared radiations (IR)

25 CFR 307.11 - Certificates fastened to fabrics.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false Certificates fastened to fabrics. 307.11 Section 307.11 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO ALL-WOOL WOVEN FABRICS; USE OF... the hand seal press furnished by the Indian Arts and Crafts Board. ...

Fabrication of porous chitosan/poly(vinyl alcohol) reinforced single-walled carbon nanotube nanocomposites for neural tissue engineering.

PubMed

Shokrgozar, Mohammad Ali; Mottaghitalab, Fatemeh; Mottaghitalab, Vahid; Farokhi, Mehdi

2011-04-01

With the ability to form a nano-sized fibrous structure with large pore sizes mimicking the extracellular matrix (ECM), electrospinning was used to fabricate chitosan/poly(vinyl alcohol) nanofibers reinforced by single-walled carbon nanotube (SWNT-CS/PVA) for potential use in neural tissue engineering. Moreover, ultrasonication was performed to fabricate highly dispersed SWNT/CS solution with 7%, 12%, and 17% SWNT content prior to electrospinning process. In the present study, a number of properties of CS/PVA reinforced SWNTs nanocomposites were evaluated. The in vitro biocompatibility of the electrospun fiber mats was also assessed using human brain-derived cells and U373 cell lines. The results have shown that SWNTs as reinforcing phase can augment the morphology, porosity, and structural properties of CS/PVA nanofiber composites and thus benefit the proliferation rate of both cell types. In addition, the cells exhibit their normal morphology while integrating with surrounding fibers. The results confirmed the potential of SWNT-CS/PVA nanocomposites as scaffold for neural tissue engineering.

75 FR 53632 - Narrow Woven Ribbons With Woven Selvedge From Taiwan and the People's Republic of China...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-01

..., style, pattern, or weave construction, including but not limited to single-faced satin, double-faced... DEPARTMENT OF COMMERCE International Trade Administration [A-583-844, A-570-952] Narrow Woven Ribbons With Woven Selvedge From Taiwan and the People's Republic of China: Antidumping Duty Orders AGENCY...

Thermoelastic characteristics testing on kevlar samples for spacecraft structures

NASA Astrophysics Data System (ADS)

Crema, L. Balis; Barboni, R.; Castellani, A.; Peroni, I.

The tensile properties, the thermal expansion coefficient and the thermal conductivity of woven roving (WR) reinforced Kevlar fabrics were experimentally determined. Theoretical values for tensile Young's modulus were calculated by simulating a fabric as an equivalent cross-ply laminate. As thermal expansion coefficient concerns the fabrics have shown an isotropic behaviour. The thermal conductivity normal to fabric plane has also been determined.

Carbon nanotube reinforced aluminum based nanocomposite fabricated by thermal spray forming

NASA Astrophysics Data System (ADS)

Laha, Tapas

The present research concentrates on the fabrication of bulk aluminum matrix nanocomposite structures with carbon nanotube reinforcement. The objective of the work was to fabricate and characterize multi-walled carbon nanotube (MWCNT) reinforced hypereutectic Al-Si (23 wt% Si, 2 wt% Ni, 1 wt% Cu, rest Al) nanocomposite bulk structure with nanocrystalline matrix through thermal spray forming techniques viz. plasma spray forming (PSF) and high velocity oxy-fuel (HVOF) spray forming. This is the first research study, which has shown that thermal spray forming can be successfully used to synthesize carbon nanotube reinforced nanocomposites. Microstructural characterization based on quantitative microscopy, scanning and transmission electron microscopy (SEM and TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Raman spectroscopy and X ray photoelectron spectroscopy (XPS) confirms (i) retention and macro/sub-macro level homogenous distribution of multiwalled carbon nanotubes in the Al-Si matrix and (ii) evolution of nanostructured grains in the matrix. Formation of ultrathin beta-SiC layer on MWCNT surface, due to chemical reaction of Si atoms diffusing from Al-Si alloy and C atoms from the outer walls of MWCNTs has been confirmed theoretically and experimentally. The presence of SiC layer at the interface improves the wettability and the interfacial adhesion between the MWCNT reinforcement and the Al-Si matrix. Sintering of the as-sprayed nanocomposites was carried out in an inert environment for further densification. As-sprayed PSF nanocomposite showed lower microhardness compared to HVOF, due to the higher porosity content and lower residual stress. The hardness of the nanocomposites increased with sintering time due to effective pore removal. Uniaxial tensile test on CNT-bulk nanocomposite was carried out, which is the first ever study of such nature. The tensile test results showed inconsistency in the data attributed to inhomogeneous

Coated woven materials and method of preparation

DOEpatents

McCreary, W.J.; Carroll, D.W.

Coating of woven materials so that not only the outer surfaces are coated has been a problem. Now, a solution to that problem is by coating with materials, with metals or with pyrolytic carbon. Materials are deposited in Chemical Vapor Deposition (CND) reactions using a fluidized bed so that the porosity of the woven materials is retained and the tiny filaments which make up the strands which are woven (including inner as well as outer filaments) are substantially uniformly coated.

3D Non-Woven Polyvinylidene Fluoride Scaffolds: Fibre Cross Section and Texturizing Patterns Have Impact on Growth of Mesenchymal Stromal Cells

PubMed Central

Schellenberg, Anne; Ross, Robin; Abagnale, Giulio; Joussen, Sylvia; Schuster, Philipp; Arshi, Annahit; Pallua, Norbert; Jockenhoevel, Stefan; Gries, Thomas; Wagner, Wolfgang

2014-01-01

Several applications in tissue engineering require transplantation of cells embedded in appropriate biomaterial scaffolds. Such structures may consist of 3D non-woven fibrous materials whereas little is known about the impact of mesh size, pore architecture and fibre morphology on cellular behavior. In this study, we have developed polyvinylidene fluoride (PVDF) non-woven scaffolds with round, trilobal, or snowflake fibre cross section and different fibre crimp patterns (10, 16, or 28 needles per inch). Human mesenchymal stromal cells (MSCs) from adipose tissue were seeded in parallel on these scaffolds and their growth was compared. Initial cell adhesion during the seeding procedure was higher on non-wovens with round fibres than on those with snowflake or trilobal cross sections. All PVDF non-woven fabrics facilitated cell growth over a time course of 15 days. Interestingly, proliferation was significantly higher on non-wovens with round or trilobal fibres as compared to those with snowflake profile. Furthermore, proliferation increased in a wider, less dense network. Scanning electron microscopy (SEM) revealed that the MSCs aligned along the fibres and formed cellular layers spanning over the pores. 3D PVDF non-woven scaffolds support growth of MSCs, however fibre morphology and mesh size are relevant: proliferation is enhanced by round fibre cross sections and in rather wide-meshed scaffolds. PMID:24728045

Mechanical Behaviour of Woven Graphite/Polyimide Composites with Medium and High Modulus Graphite Fibers Subjected to Biaxial Shear Dominated Loads

NASA Technical Reports Server (NTRS)

Kumose, M.; Gentz, M.; Rupnowski, P.; Armentrout, D.; Kumosa, L.; Shin, E.; Sutter, J. K.

2003-01-01

A major limitation of woven fiber/polymer matrix composite systems is the inability of these materials to resist intralaminar and interlaminar damage initiation and propagation under shear-dominated biaxial loading conditions. There are numerous shear test methods for woven fabric composites, each with its own advantages and disadvantages. Two techniques, which show much potential, are the Iosipescu shear and +/- 45 deg tensile tests. In this paper, the application of these two tests for the room and high temperature failure analyses of woven graphite/polyimide composites is briefly evaluated. In particular, visco-elastic micro, meso, and macro-stress distributions in a woven eight harness satin (8HS) T650/PMR-15 composite subjected to these two tests are presented and their effect on the failure process of the composite is evaluated. Subsequently, the application of the Iosipescu tests to the failure analysis of woven composites with medium (T650) and high (M40J and M60J) modulus graphite fibers and PMR-15 and PMR-II-50 polyimide resins is discussed. The composites were tested as-supplied and after thermal conditioning. The effect of temperature and thermal conditioning on the initiation of intralaminar damage and the shear strength of the composites was established.

Light emitting fabric technologies for photodynamic therapy.

PubMed

Mordon, Serge; Cochrane, Cédric; Tylcz, Jean Baptiste; Betrouni, Nacim; Mortier, Laurent; Koncar, Vladan

2015-03-01

Photodynamic therapy (PDT) is considered to be a promising method for treating various types of cancer. A homogeneous and reproducible illumination during clinical PDT plays a determinant role in preventing under- or over-treatment. The development of flexible light sources would considerably improve the homogeneity of light delivery. The integration of optical fiber into flexible structures could offer an interesting alternative. This paper aims to describe different methods proposed to develop Side Emitting Optical Fibers (SEOF), and how these SEOF can be integrated in a flexible structure to improve light illumination of the skin during PDT. Four main techniques can be described: (i) light blanket integrating side-glowing optical fibers, (ii) light emitting panel composed of SEOF obtained by micro-perforations of the cladding, (iii) embroidery-based light emitting fabric, and (iv) woven-based light emitting fabric. Woven-based light emitting fabrics give the best performances: higher fluence rate, best homogeneity of light delivery, good flexibility. Copyright © 2014 Elsevier B.V. All rights reserved.

Carbon fiber reinforced hierarchical orthogrid stiffened cylinder: Fabrication and testing

NASA Astrophysics Data System (ADS)

Wu, Hao; Lai, Changlian; Sun, Fangfang; Li, Ming; Ji, Bin; Wei, Weiyi; Liu, Debo; Zhang, Xi; Fan, Hualin

2018-04-01

To get strong, stiff and light cylindrical shell, carbon fiber reinforced hierarchical orthogrid stiffened cylinders are designed and fabricated. The cylinder is stiffened by two-scale orthogrid. The primary orthogrid has thick and high ribs and contains several sub-orthogrid cells whose rib is much thinner and lower. The primary orthogrid stiffens the bending rigidity of the cylinder to resist the global instability while the sub-orthogrid stiffens the bending rigidity of the skin enclosed by the primary orthogrid to resist local buckling. The cylinder is fabricated by filament winding method based on a silicone rubber mandrel with hierarchical grooves. Axial compression tests are performed to reveal the failure modes. With hierarchical stiffeners, the cylinder fails at skin fracture and has high specific strength. The cylinder will fail at end crushing if the end of the cylinder is not thickened. Global instability and local buckling are well restricted by the hierarchical stiffeners.

Fabrication and characterization of jute fabrics reinforced polypropylene-based composites: effects of ionizing radiation and disaccharide (sucrose)

NASA Astrophysics Data System (ADS)

Sahadat Hossain, Md.; Uddin, Muhammad B.; Razzak, Md.; Sarwaruddin Chowdhury, A. M.; Khan, Ruhul A.

2017-12-01

Composites were prepared successfully by compression molding technique using jute fabrics (reinforcing agent) and polypropylene (matrix). Jute fabrics were treated with disaccharide (sucrose) solution and composites were fabricated with the treated fabric and polypropylene. The fiber content of the prepared composites was 40% by weight. It was found that the sucrose (2% solution) decreased the tensile strength (TS) and elongation at break about 6% and 37%, respectively, but tensile modulus and impact strength improved about 27% and 32%, respectively. When gamma radiation was applied through the untreated and treated composites the mechanical properties were improved much higher in non-treated Jute/PP-based composites than that of sucrose treated composites. For 5.0 kGy gamma dose the highest mechanical properties were observed for non-treated composites. At 5.0 kGy gamma dose the improvement of TS was 14% and 2% for non-treated and sucrose treated composites, respectively. The water uptake property of the sucrose treated composites was performed up to 10 days and composites absorbed 18% water. The functional groups of the both composites were analyzed by Fourier transform infrared spectroscopy machine. The scanning electron microscopic images of the both composites were taken for the surface and fiber adhesion analysis.

In-situ growth of high-performance all-solid-state electrode for flexible supercapacitors based on carbon woven fabric/ polyaniline/ graphene composite

NASA Astrophysics Data System (ADS)

Lin, Yingxi; Zhang, Haiyan; Deng, Wentao; Zhang, Danfeng; Li, Na; Wu, Qibai; He, Chunhua

2018-04-01

For the development of wearable electronic devices, it is crucial to develop energy storage components combining high-capacity and flexibility. Herein, an all-solid-state supercapacitor is prepared through an in-situ "growth and wrapping" method. The electrode contains polyaniline deposited on a carbon woven fabric and wrapped with a graphene-based envelop. The hybrid electrode exhibits excellent mechanical and electrochemical performance. The optimized few layer graphene wrapping layer provides for a conductive network, which effectively enhances the cycling stability as 88.9% of the starting capacitance is maintained after 5000 charge/discharge cycles. Furthermore, the assembled device delivers a high areal capacity (of 790 F cm-2) at the current density of 1 A cm-2, a high areal energy (28.21 uWh cm-2) at the power densities of 0.12 mW cm-2 and shows no significant decrease in the performance with a bending angle of 180°. This unique flexible supercapacitor thus exhibits great potential for wearable electronics.

77 FR 47363 - Narrow Woven Ribbons With Woven Selvedge From the People's Republic of China: Preliminary Results...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-08

..., polyester, rayon, polypropylene, and polyethylene teraphthalate), metal threads and/or metalized yarns, or... original length as defined in the (HTSUS, Section XI, Note 13) or rubber thread; (4) Narrow woven ribbons... comprised at least 85 percent by weight of threads having a denier of 225 or higher; (9) Narrow woven...

78 FR 10130 - Narrow Woven Ribbons With Woven Selvedge From the People's Republic of China: Final Results of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-13

... Department selected two respondents for review, Precious Planet Ribbons & Bows Co., Ltd. (``Precious Planet'') and Hubschercorp. On January 24, 2012, Precious Planet timely withdrew its request for an...\\ See Letter from Precious Planet to the Secretary of Commerce, ``Narrow Woven Ribbons With Woven...

In vitro evaluation of the flexural properties of All-on-Four provisional fixed denture base resin partially reinforced with fibers.

PubMed

Li, Bei Bei; Xu, Jia Bin; Cui, Hong Yan; Lin, Ye; Di, Ping

2016-01-01

The aim of this study was to assess the effects of partial carbon or glass fiber reinforcement on the flexural properties of All-on-Four provisional fixed denture base resin. The carbon or glass fibers were woven (3% by weight) together in three strands and twisted and tightened between the two abutments in a figure-of-"8" pattern. Four types of specimens were fabricated for the three-point loading test. The interface between the denture base resin and fibers was examined using scanning electron microscopy (SEM). Reinforcement with carbon or glass fibers between two abutments significantly increased the flexural strength and flexural modulus. SEM revealed relatively continuous contact between the fibers and acrylic resin. The addition of carbon or glass fibers between two abutments placed on All-on-Four provisional fixed denture base resin may be clinically effective in preventing All-on-Four denture fracture and can provide several advantages for clinical use.

Crimp-Imbalanced Protective (CRIMP) Fabrics: An Analytical Investigation into the Relationship Between Crimp Contents, Energy Absorption, and Fabric Ballistic Performance

DTIC Science & Technology

2010-09-15

migration and yarn stretching. These mechanisms relate to the force required to pull a yarn out from the fabric. If the fabric is made of low...the following assumptions were made : The fabric architecture is plain-woven. The yarns have a circular cross section with diameter D equal to 1.0... Bulletproof Aramid Fabric," Journal of Materials Science, vol. 32, pp. 4167-4173, 1997. 16. D. A. Shockey, D. C. Erlich, and J. W. Simons, "Improved

Glass fibre-reinforced composite laced with chlorhexidine digluconate and yeast adhesion.

PubMed

Waltimo, T; Luo, G; Samaranayake, L P; Vallittu, P K

2004-02-01

The aim of this study was to lace dental glass fibre reinforced composite (FRC) prepreg with chlorhexidine digluconate and to examine the adherence of common oral fungal pathogen Candida albicans to FRC made of the prepreg. Four different test and control material groups each comprising 16 test specimens ((5.0 x 5.0 x 0.8) mm3) each were used as substrates for C. albicans adherence. A porous polymer pre-impregnated woven glass fibre prepreg was laced with solution of chlorhexidine gluconate and it was used with autopolymerized denture base polymer to fabricate FRC test specimens. Control group (Group 1) consisted of FRC test specimens stored in water. In Group 2, the test specimens were stored in 10% chlorhexidine digluconate solution for 24 h. Group 3 consisted of specimens fabricated using such fibre reinforcements which were pre-soaked in 20% chlorhexidine digluconate and dried before preparation with denture base resin, and followed by storage of the specimens in water. Group 4 was similar to Group 3 but instead of water storage the specimens were immersed in 10% chlorhexidine digluconate for 24 h. For the candidal adhesion assay the test and control specimens were incubated in standardized suspensions of four different strains of C. albicans, rinsed and prepared for light-microscopy. The mean number of adherent cells in each group was counted microscopically and analysed statistically. There were significantly (P < 0.05) more adherent C. albicans cells found in Group 1 than in the other three groups which did not differ significantly from each other. The lowest numbers of adherent cells were found in Group 3. Pretreating the porous polymer pre-impregnated glass fibre reinforcement with chlorhexidine digluconate result in reduction in the number of adherent yeast cells on the surface FRC material.

High Temperature Si-doped BN Interphases for Woven SiC/SiC Composites

NASA Technical Reports Server (NTRS)

Morscher, Gregory N.; Hurwitz, Frances; Yun, Hee Mann; Gray, Hugh R. (Technical Monitor)

2002-01-01

The hydrolytic stability of high-temperature deposited Si-doped BN has been shown in the past to be superior in comparison to "pure" BN processed at similar or even higher temperatures. This type of material would be very desirable as a SiC/SiC composite interphase that is formed by chemical infiltration into multi-ply woven preform. However, due to rapid deposition on the preform outer surface at the high processing temperature, this has proven very difficult. To overcome this issue, single plies of woven fabric were infiltrated with Si-doped BN. Three composite panels of different SiC fiber types were fabricated with Si-doped BN interphases including Sylramic, Hi-Nicalon Type S and Sylramic-iBN fiber-types. The latter fiber-type possesses a thin in-situ grown BN layer on the fiber surface. High Si contents (approx. 7 to 10 a/o) and low oxygen contents (less than 1 a/o) were achieved. All three composite systems demonstrated reasonable debonding and sliding properties. The coated Sylramic fabric and composites were weak due to fiber degradation apparently caused during interphase processing by the formation of TiN crystals on the fiber surface. The Hi-Nicalon Type S composites with Si-doped BN interphase were only slightly weaker than Hi-Nicalon Type S composites with conventional BN when the strength on the load-bearing fibers at failure was compared. On the other hand, the Sylramic-iBN fabric and composites with Si-doped BN showed excellent composite and intermediate temperature stress-rupture properties. Most impressive was the lack of any significant interphase oxidation on the fracture surface of stress-ruptured specimens tested well above matrix cracking at 815C.

Fabrication of high-density In3Sb1Te2 phase change nanoarray on glass-fabric reinforced flexible substrate

NASA Astrophysics Data System (ADS)

Yoon, Jong Moon; Shin, Dong Ok; Yin, You; Seo, Hyeon Kook; Kim, Daewoon; In Kim, Yong; Jin, Jung Ho; Kim, Yong Tae; Bae, Byeong-Soo; Ouk Kim, Sang; Lee, Jeong Yong

2012-06-01

Mushroom-shaped phase change memory (PCM) consisting of a Cr/In3Sb1Te2 (IST)/TiN (bottom electrode) nanoarray was fabricated via block copolymer lithography and single-step dry etching with a gas mixture of Ar/Cl2. The process was performed on a high performance transparent glass-fabric reinforced composite film (GFR Hybrimer) suitable for use as a novel substrate for flexible devices. The use of GFR Hybrimer with low thermal expansion and flat surfaces enabled successful nanoscale patterning of functional phase change materials on flexible substrates. Block copolymer lithography employing asymmetrical block copolymer blends with hexagonal cylindrical self-assembled morphologies resulted in the creation of hexagonal nanoscale PCM cell arrays with an areal density of approximately 176 Gb/in2.

49 CFR 178.518 - Standards for woven plastic bags.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Standards for woven plastic bags. 178.518 Section... PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.518 Standards for woven plastic bags. (a) The following are identification codes for woven plastic bags: (1) 5H1 for an unlined or non-coated...

Non-Wovens as Sound Reducers

NASA Astrophysics Data System (ADS)

Belakova, D.; Seile, A.; Kukle, S.; Plamus, T.

2018-04-01

Within the present study, the effect of hemp (40 wt%) and polyactide (60 wt%), non-woven surface density, thickness and number of fibre web layers on the sound absorption coefficient and the sound transmission loss in the frequency range from 50 to 5000 Hz is analysed. The sound insulation properties of the experimental samples have been determined, compared to the ones in practical use, and the possible use of material has been defined. Non-woven materials are ideally suited for use in acoustic insulation products because the arrangement of fibres produces a porous material structure, which leads to a greater interaction between sound waves and fibre structure. Of all the tested samples (A, B and D), the non-woven variant B exceeded the surface density of sample A by 1.22 times and 1.15 times that of sample D. By placing non-wovens one above the other in 2 layers, it is possible to increase the absorption coefficient of the material, which depending on the frequency corresponds to C, D, and E sound absorption classes. Sample A demonstrates the best sound absorption of all the three samples in the frequency range from 250 to 2000 Hz. In the test frequency range from 50 to 5000 Hz, the sound transmission loss varies from 0.76 (Sample D at 63 Hz) to 3.90 (Sample B at 5000 Hz).

Application of a Fiber Optic Distributed Strain Sensor System to Woven E-Glass Composite

NASA Technical Reports Server (NTRS)

Anastasi, Robert F.; Lopatin, Craig

2001-01-01

A distributed strain sensing system utilizing a series of identically written Bragg gratings along an optical fiber is examined for potential application to Composite Armored Vehicle health monitoring. A vacuum assisted resin transfer molding process was used to fabricate a woven fabric E-glass/composite panel with an embedded fiber optic strain sensor. Test samples machined from the panel were mechanically tested in 4-point bending. Experimental results are presented that show the mechanical strain from foil strain gages comparing well to optical strain from the embedded sensors. Also, it was found that the distributed strain along the sample length was consistent with the loading configuration.

Evaluation of microplastic release caused by textile washing processes of synthetic fabrics.

PubMed

De Falco, Francesca; Gullo, Maria Pia; Gentile, Gennaro; Di Pace, Emilia; Cocca, Mariacristina; Gelabert, Laura; Brouta-Agnésa, Marolda; Rovira, Angels; Escudero, Rosa; Villalba, Raquel; Mossotti, Raffaella; Montarsolo, Alessio; Gavignano, Sara; Tonin, Claudio; Avella, Maurizio

2018-05-01

A new and more alarming source of marine contamination has been recently identified in micro and nanosized plastic fragments. Microplastics are difficult to see with the naked eye and to biodegrade in marine environment, representing a problem since they can be ingested by plankton or other marine organisms, potentially entering the food web. An important source of microplastics appears to be through sewage contaminated by synthetic fibres from washing clothes. Since this phenomenon still lacks of a comprehensive analysis, the objective of this contribution was to investigate the role of washing processes of synthetic textiles on microplastic release. In particular, an analytical protocol was set up, based on the filtration of the washing water of synthetic fabrics and on the analysis of the filters by scanning electron microscopy. The quantification of the microfibre shedding from three different synthetic fabric types, woven polyester, knitted polyester, and woven polypropylene, during washing trials simulating domestic conditions, was achieved and statistically analysed. The highest release of microplastics was recorded for the wash of woven polyester and this phenomenon was correlated to the fabric characteristics. Moreover, the extent of microfibre release from woven polyester fabrics due to different detergents, washing parameters and industrial washes was evaluated. The number of microfibres released from a typical 5 kg wash load of polyester fabrics was estimated to be over 6,000,000 depending on the type of detergent used. The usage of a softener during washes reduces the number of microfibres released of more than 35%. The amount and size of the released microfibres confirm that they could not be totally retained by wastewater treatments plants, and potentially affect the aquatic environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Carbon nanotube woven textile photodetector

NASA Astrophysics Data System (ADS)

Zubair, Ahmed; Wang, Xuan; Mirri, Francesca; Tsentalovich, Dmitri E.; Fujimura, Naoki; Suzuki, Daichi; Soundarapandian, Karuppasamy P.; Kawano, Yukio; Pasquali, Matteo; Kono, Junichiro

2018-01-01

The increasing interest in mobile and wearable technology demands the enhancement of functionality of clothing through incorporation of sophisticated architectures of multifunctional materials. Flexible electronic and photonic devices based on organic materials have made impressive progress over the past decade, but higher performance, simpler fabrication, and most importantly, compatibility with woven technology are desired. Here we report on the development of a weaved, substrateless, and polarization-sensitive photodetector based on doping-engineered fibers of highly aligned carbon nanotubes. This room-temperature-operating, self-powered detector responds to radiation in an ultrabroad spectral range, from the ultraviolet to the terahertz, through the photothermoelectric effect, with a low noise-equivalent power (a few nW/Hz 1 /2) throughout the range and with a Z T -factor value that is twice as large as that of previously reported carbon nanotube-based photothermoelectric photodetectors. Particularly, we fabricated a ˜1 -m-long device consisting of tens of p+-p- junctions and weaved it into a shirt. This device demonstrated a collective photoresponse of the series-connected junctions under global illumination. The performance of the device did not show any sign of deterioration through 200 bending tests with a bending radius smaller than 100 μ m as well as standard washing and ironing cycles. This unconventional photodetector will find applications in wearable technology that require detection of electromagnetic radiation.

Damage Tolerance Testing of a NASA TransHab Derivative Woven Inflatable Module

NASA Technical Reports Server (NTRS)

Edgecombe, John; delaFuente, Horacio; Valle, Gerard

2009-01-01

Current options for Lunar habitat architecture include inflatable habitats and airlocks. Inflatable structures can have mass and volume advantages over conventional structures. However, inflatable structures carry different inherent risks and are at a lower Technical Readiness Level (TRL) than more conventional metallic structures. One of the risks associated with inflatable structures is in understanding the tolerance to induced damage. The Damage Tolerance Test (DTT) is designed to study the structural integrity of an expandable structure. TransHab (Figure 1) was an experimental inflatable module developed at the NASA/Johnson Space Center in the 1990 s. The TransHab design was originally envisioned for use in Mars Transits but was also studied as a potential habitat for the International Space Station (ISS). The design of the TransHab module was based on a woven design using an Aramid fabric. Testing of this design demonstrated a high level of predictability and repeatability with analytical predictions of stresses and deflections. Based on JSC s experience with the design and analysis of woven inflatable structures, the Damage Tolerance Test article was designed and fabricated using a woven design. The DTT article was inflated to 45 psig, representing 25% of the ultimate burst pressure, and one of the one-inch wide longitudinal structural members was severed by initiating a Linear Shaped Charge (LSC). Strain gage measurements, at the interface between the expandable elements (straps) and the nonexpandable metallic elements for pre-selected longitudinal straps, were taken throughout pressurization of the module and strap separation. Strain gage measurements show no change in longitudinal strap loading at the bulkhead interface after strap separation indicating loads in the restraint layer were re-distributed local to the damaged area due to the effects of friction under high internal pressure loading. The test completed all primary objectives with better than

An instrument for measuring bacterial penetration through fabrics used for barrier clothing.

PubMed Central

Ransjö, U.; Hambraeus, A.

1979-01-01

A new instrument has been designed to measure the penetration by rubbing of bacteria from cloth contaminated in the nursing of burn patients through fabrics designed for barrier garments. Most fabrics tested dry reduced the transfer of bacteria from the source cloth to about 10%, irrespective of the results of air filter tests, which agrees with mock nursing results. When the fabrics were tested against a wet surface, the transfer of bacteria rapidly reached 100% if the fabrics had a high wettability, but was slower for fabrics with a low wettability. Through closely woven waterproofed cotton, transfer was 5--25%, but increased three- to four-fold after ten launderings, in line with the water absorption. Transfer through plastic-laminated material was less than 1%. The results suggest that barrier garments should be made either of plastic or of recently waterproofed closely woven cotton at points of contact between nurse and patient where the clothes may be wetted by bacteria-containing wound secretions. Images Plate 1 PMID:376694

Quantitative analysis of the radiation error for aerial coiled-fiber-optic distributed temperature sensing deployments using reinforcing fabric as support structure

NASA Astrophysics Data System (ADS)

Sigmund, Armin; Pfister, Lena; Sayde, Chadi; Thomas, Christoph K.

2017-06-01

In recent years, the spatial resolution of fiber-optic distributed temperature sensing (DTS) has been enhanced in various studies by helically coiling the fiber around a support structure. While solid polyvinyl chloride tubes are an appropriate support structure under water, they can produce considerable errors in aerial deployments due to the radiative heating or cooling. We used meshed reinforcing fabric as a novel support structure to measure high-resolution vertical temperature profiles with a height of several meters above a meadow and within and above a small lake. This study aimed at quantifying the radiation error for the coiled DTS system and the contribution caused by the novel support structure via heat conduction. A quantitative and comprehensive energy balance model is proposed and tested, which includes the shortwave radiative, longwave radiative, convective, and conductive heat transfers and allows for modeling fiber temperatures as well as quantifying the radiation error. The sensitivity of the energy balance model to the conduction error caused by the reinforcing fabric is discussed in terms of its albedo, emissivity, and thermal conductivity. Modeled radiation errors amounted to -1.0 and 1.3 K at 2 m height but ranged up to 2.8 K for very high incoming shortwave radiation (1000 J s-1 m-2) and very weak winds (0.1 m s-1). After correcting for the radiation error by means of the presented energy balance, the root mean square error between DTS and reference air temperatures from an aspirated resistance thermometer or an ultrasonic anemometer was 0.42 and 0.26 K above the meadow and the lake, respectively. Conduction between reinforcing fabric and fiber cable had a small effect on fiber temperatures (< 0.18 K). Only for locations where the plastic rings that supported the reinforcing fabric touched the fiber-optic cable were significant temperature artifacts of up to 2.5 K observed. Overall, the reinforcing fabric offers several advantages over

Environmental Effects on Long Term Displacement Data of Woven Fabric Webbings Under Constant Load for Inflatable Structures

NASA Technical Reports Server (NTRS)

Kenner, WInfred S.; Jones, Thomas C.; Doggett, William R.; Duncan, Quinton; Plant, James

2015-01-01

An experimental study of the effects of environmental temperature and humidity conditions on long-term creep displacement data of high strength Kevlar and VectranTM woven fabric webbings under constant load for inflatable structures is presented. The restraint layer of an inflatable structure for long-duration space exploration missions is designed to bear load and consists of an assembly of high strength webbings. Long-term creep displacement data of webbings can be utilized by designers to validate service life parameters of restraint layers of inflatable structures. Five groups of high-strength webbings were researched over a two year period. Each group had a unique webbing length, load rating, applied load, and test period. The five groups consisted of 1.) 6K Vectran webbings loaded to 49% ultimate tensile strength (UTS), 2.) 6K Vectran webbings loaded to 55% UTS, 3.) 12.5K Vectran webbings loaded to 22% UTS, 4.) 6K Kevlar webbings loaded to 40% and 43% UTS, and 5.) 6K Kevlar webbings loaded to 48% UTS. Results show that all webbing groups exhibit the initial two stages of three of a typical creep curve of an elastic material. Results also show that webbings exhibit unique local wave patterns over the duration of the test period. Data indicate that the local pattern is primarily generated by daily variations in relative humidity values within the test facility. Data indicate that after a three to six month period, where webbings reach a steady-state creep condition, an annual sinusoidal displacement pattern is exhibited, primarily due to variations in annual mean temperature values. Data indicates that variations in daily temperature values and annual mean humidity values have limited secondary effects on creep displacement behavior. Results show that webbings in groups 2 and 5 do not exhibit well defined annual displacement patterns because the magnitude of the applied loads cause large deformations, and data indicate that material yielding within a webbing

Angle-Ply Weaving

NASA Technical Reports Server (NTRS)

Farley, Gary L.

1990-01-01

Bias-direction or angle-ply weaving is proposed new process for weaving fibers along bias in conventional planar fabric or in complicated three-dimensional multilayer fabric preform of fiber-reinforced composite structure. Based upon movement of racks of needles and corresponding angle yarns across fabric as fabric being formed. Fibers woven along bias increases shear stiffness and shear strength of preform, increasing value of preform as structural member.

75 FR 41804 - Notice of Final Determination of Sales at Less Than Fair Value: Narrow Woven Ribbons with Woven...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-19

... include natural or other non-man-made fibers; be of any color, style, pattern, or weave construction..., jacquard, or a combination of two or more colors, styles, patterns, and/or weave constructions; have been... of Sales at Less Than Fair Value: Narrow Woven Ribbons with Woven Selvedge from Taiwan AGENCY: Import...

Recycling of Reinforced Plastics

NASA Astrophysics Data System (ADS)

Adams, R. D.; Collins, Andrew; Cooper, Duncan; Wingfield-Digby, Mark; Watts-Farmer, Archibald; Laurence, Anna; Patel, Kayur; Stevens, Mark; Watkins, Rhodri

2014-02-01

This work has shown is that it is possible to recycle continuous and short fibre reinforced thermosetting resins while keeping almost the whole of the original material, both fibres and matrix, within the recyclate. By splitting, crushing hot or cold, and hot forming, it is possible to create a recyclable material, which we designate a Remat, which can then be used to remanufacture other shapes, examples of plates and tubes being demonstrated. Not only can remanufacturing be done, but it has been shown that over 50 % of the original mechanical properties, such as the E modulus, tensile strength, and interlaminar shear strength, can be retained. Four different forms of composite were investigated, a random mat Glass Fibre Reinforced Plastic (GFRP) bathroom component and boat hull, woven glass and carbon fibre cloth impregnated with an epoxy resin, and unidirectional carbon fibre pre-preg. One of the main factors found to affect composite recyclability was the type of resin matrix used in the composite. Thermoset resins tested were shown to have a temperature range around the Glass Transition Temperature (Tg) where they exhibit ductile behaviour, hence aiding reforming of the material. The high-grade carbon fibre prepreg was found to be less easy to recycle than the woven of random fibre laminates. One method of remanufacturing was by heating the Remat to above its glass transition temperature, bending it to shape, and then cooling it. However, unless precautions are taken, the geometric form may revert. This does not happen with the crushed material.

Fabrication and Synthesis of Highly Ordered Nickel Cobalt Sulfide Nanowire-Grown Woven Kevlar Fiber/Reduced Graphene Oxide/Polyester Composites.

PubMed

Hazarika, Ankita; Deka, Biplab K; Kim, DoYoung; Roh, Hyung Doh; Park, Young-Bin; Park, Hyung Wook

2017-10-18

Well-aligned NiCo 2 S 4 nanowires, synthesized hydrothermally on the surface of woven Kevlar fiber (WKF), were used to fabricate composites with reduced graphene oxide (rGO) dispersed in polyester resin (PES) by means of vacuum-assisted resin transfer molding. The NiCo 2 S 4 nanowires were synthesized with three precursor concentrations. Nanowire growth was characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Hierarchical and high growth density of the nanowires led to exceptional mechanical properties of the composites. Compared with bare WKF/PES, the tensile strength and absorbed impact energy were enhanced by 96.2% and 92.3%, respectively, for WKF/NiCo 2 S 4 /rGO (1.5%)/PES. The synergistic effect of NiCo 2 S 4 nanowires and rGO in the fabricated composites improved the electrical conductivity of insulating WKF/PES composites, reducing the resistance to ∼10 3 Ω. Joule heating performance depended strongly on the precursor concentration of the nanowires and the presence of rGO in the composite. A maximum surface temperature of 163 °C was obtained under low-voltage (5 V) application. The Joule heating performance of the composites was demonstrated in a surface deicing experiment; we observed that 17 g of ice melted from the surface of the composite in 14 min under an applied voltage of 5 V at -28 °C. The excellent performance of WKF/NiCo 2 S 4 /rGO/PES composites shows great potential for aerospace structural applications requiring outstanding mechanical properties and Joule heating capability for deicing of surfaces.

Numerical simulating and experimental study on the woven carbon fiber-reinforced composite laminates under low-velocity impact

NASA Astrophysics Data System (ADS)

Liu, Hanyang; Tang, Zhanwen; Pan, Lingying; Zhao, Weidong; Sun, Baogang; Jiang, Wenge

2016-05-01

Impact damage has been identified as a critical form of the defects that constantly threatened the reliability of composite structures, such as those used in the aerospace structures and systems. Low energy impacts can introduce barely visible damage and cause the degradation of structural stiffness, furthermore, the flaws caused by low-velocity impact are so dangerous that they can give rise to the further extended delaminations. In order to improve the reliability and load carrying capacity of composite laminates under low-velocity impact, in this paper, the numerical simulatings and experimental studies on the woven fiber-reinforced composite laminates under low-velocity impact with impact energy 16.7J were discussed. The low velocity impact experiment was carried out through drop-weight system as the reason of inertia effect. A numerical progressive damage model was provided, in which the damages of fiber, matrix and interlamina were considered by VUMT subroutine in ABAQUS, to determine the damage modes. The Hashin failure criteria were improved to cover the failure modes of fiber failure in the directions of warp/weft and delaminations. The results of Finite Element Analysis (FEA) were compared with the experimental results of nondestructive examination including the results of ultrasonic C-scan, cross-section stereomicroscope and contact force - time history curves. It is found that the response of laminates under low-velocity impact could be divided into stages with different damage. Before the max-deformation of the laminates occurring, the matrix cracking, fiber breakage and delaminations were simulated during the impactor dropping. During the releasing and rebounding period, matrix cracking and delaminations areas kept increasing in the laminates because of the stress releasing of laminates. Finally, the simulating results showed the good agreements with the results of experiment.

Failure Progress of 3D Reinforced GFRP Laminate during Static Bending, Evaluated by Means of Acoustic Emission and Vibrations Analysis.

PubMed

Koziol, Mateusz; Figlus, Tomasz

2015-12-14

The work aimed to assess the failure progress in a glass fiber-reinforced polymer laminate with a 3D-woven and (as a comparison) plain-woven reinforcement, during static bending, using acoustic emission signals. The innovative method of the separation of the signal coming from the fiber fracture and the one coming from the matrix fracture with the use of the acoustic event's energy as a criterion was applied. The failure progress during static bending was alternatively analyzed by evaluation of the vibration signal. It gave a possibility to validate the results of the acoustic emission. Acoustic emission, as well as vibration signal analysis proved to be good and effective tools for the registration of failure effects in composite laminates. Vibration analysis is more complicated methodologically, yet it is more precise. The failure progress of the 3D laminate is "safer" and more beneficial than that of the plain-woven laminate. It exhibits less rapid load capacity drops and a higher fiber effort contribution at the moment of the main laminate failure.

Development of Rapid Pipe Moulding Process for Carbon Fiber Reinforced Thermoplastics by Direct Resistance Heating

NASA Astrophysics Data System (ADS)

Tanaka, Kazuto; Harada, Ryuki; Uemura, Toshiki; Katayama, Tsutao; Kuwahara, Hideyuki

To deal with environmental issues, the gasoline mileage of passenger cars can be improved by reduction of the car weight. The use of car components made of Carbon Fiber Reinforced Plastics (CFRP) is increasing because of its superior mechanical properties and relatively low density. Many vehicle structural parts are pipe-shaped, such as suspension arms, torsion beams, door guard bars and impact beams. A reduction of the car weight is expected by using CFRP for these parts. Especially, when considering the recyclability and ease of production, Carbon Fiber Reinforced Thermoplastics are a prime candidate. On the other hand, the moulding process of CFRTP pipes for mass production has not been well established yet. For this pipe moulding process an induction heating method has been investigated already, however, this method requires a complicated coil system. To reduce the production cost, another system without such complicated equipment is to be developed. In this study, the pipe moulding process of CFRTP using direct resistance heating was developed. This heating method heats up the mould by Joule heating using skin effect of high-frequency current. The direct resistance heating method is desirable from a cost perspective, because this method can heat the mould directly without using any coils. Formerly developed Non-woven Stitched Multi-axial Cloth (NSMC) was used as semi-product material. NSMC is very suitable for the lamination process due to the fact that non-crimp stitched carbon fiber of [0°/+45°/90°/-45°] and polyamide 6 non-woven fabric are stitched to one sheet, resulting in a short production cycle time. The use of the pipe moulding process with the direct resistance heating method in combination with the NSMC, has resulted in the successful moulding of a CFRTP pipe of 300 mm in length, 40 mm in diameter and 2 mm in thickness.

Evaluation of the effect of synthetic fibers and nonwoven geotextile reinforcement on the stability of heavy clay embankments.

DOT National Transportation Integrated Search

2003-04-01

This study evaluates two methods for repairing slope surface failures of clayey soil embankments. One method involves reinforcing the cohesive soils with randomly oriented synthetic fibers; the other method incorporates non-woven geotextiles. The per...

Using In situ Dynamic Cultures to Rapidly Biofabricate Fabric-Reinforced Composites of Chitosan/Bacterial Nanocellulose for Antibacterial Wound Dressings

PubMed Central

Zhang, Peng; Chen, Lin; Zhang, Qingsong; Hong, Feng F.

2016-01-01

Bacterial nano-cellulose (BNC) is considered to possess incredible potential in biomedical applications due to its innate unrivaled nano-fibrillar structure and versatile properties. However, its use is largely restricted by inefficient production and by insufficient strength when it is in a highly swollen state. In this study, a fabric skeleton reinforced chitosan (CS)/BNC hydrogel with high mechanical reliability and antibacterial activity was fabricated by using an efficient dynamic culture that could reserve the nano-fibrillar structure. By adding CS in culture media to 0.25–0.75% (w/v) during bacterial cultivation, the CS/BNC composite hydrogel was biosynthesized in situ on a rotating drum composed of fabrics. With the proposed method, BNC biosynthesis became less sensitive to the adverse antibacterial effects of CS and the production time of the composite hydrogel with desirable thickness could be halved from 10 to 5 days as compared to the conventional static cultures. Although, its concentration was low in the medium, CS accounted for more than 38% of the CS/BNC dry weight. FE-SEM observation confirmed conservation of the nano-fibrillar networks and covering of CS on BNC. ATR-FTIR showed a decrease in the degree of intra-molecular hydrogen bonding and water absorption capacity was improved after compositing with CS. The fabric-reinforced CS/BNC composite exhibited bacteriostatic properties against Escherichia coli and Staphylococcus aureus and significantly improved mechanical properties as compared to the BNC sheets from static culture. In summary, the fabric-reinforced CS/BNC composite constitutes a desired candidate for advanced wound dressings. From another perspective, coating of BNC or CS/BNC could upgrade the conventional wound dressings made of cotton gauze to reduce pain during wound healing, especially for burn patients. PMID:26973634

Polyester non-woven fabric finger cover as a TRUCT Braille reading assistance tool for Braille learners.

PubMed

Doi, Kouki; Fujimoto, Hiroshi

2007-11-01

Transparent resinous ultraviolet-curing type (TRUCT) Braille signs are becoming more and more popular in Japan, especially when they are printed together with visual characters. These signs are made by screen printing, a technique that can be applied to various base materials, such as paper, metal, and plastic. TRUCT Braille signs have begun to be used in public facilities, such as on tactile maps and on handrails. Naturally, it is expected that Braille beginners will utilize these signs. However, it has been pointed out that the friction between the forefinger and the base material may affect reading accuracy and speed. In this study, we developed a finger cover made of soft, thin polyester non-woven fabric to reduce friction during Braille reading. We also carried out a study to investigate the effect of its use. The subjects were 12 Braille learners with acquired visual impairment, who were asked to read randomly selected characters with and without the finger cover. The results showed that most participants could read TRUCT Braille significantly faster and more accurately with a finger cover than without it, regardless of the base material and dot height. This result suggests that wearing the finger cover enables Braille learners to read TRUCT Braille more efficiently. The finger cover can be used as a Braille reading assistance tool for Braille learners. An additional, health-related advantage of the finger cover is that the forefinger remains clean. We expect that the finger cover will be in practical use in Japan within 1 or 2 years.

Modeling and characterization of through-the-thickness properties of 3D woven composites

NASA Technical Reports Server (NTRS)

Hartranft, Dru; Pravizi-Majidi, Azar; Chou, Tsu-Wei

1995-01-01

The through-the-thickness properties of three-dimensionally (3D) woven carbon/epoxy composites have been studied. The investigation aimed at the evaluation and development of test methodologies for the property characterization in the thickness direction, and the establishment of fiber architectures were studied: layer-to-layer Angle Interlock, through-the-thickness Orthogonal woven preform with surface pile was also designed and manufactured for the fabrication of tensile test coupons with integrated grips. All the preforms were infiltrated by the resin transfer molding technique. The microstructures of the composites were characterized along the warp and fill (weft) directions to determine the degree of yarn undulations, yarn cross-sectional shapes, and microstructural dimensions. These parameters were correlated to the fiber architecture. Specimens were designed and tested for the direct measurement of the through-the-thickness tensile, compressive and shear properties of the composites. Design optimization was conducted through the analysis of the stress fields within the specimen coupled with experimental verification. The experimentally-derived elastic properties in the thickness direction compared well with analytical predictions obtained from a volume averaging model.

Woven ribbon cable for cryogenic instruments

NASA Astrophysics Data System (ADS)

Cunningham, C. R.; Hastings, P. R.; Strachan, J. M. D.

Robust woven ribbon cables are described for connecting sensors at low temperatures to higher temperature systems. Woven cables have several advantages over conventional wiring or flat ribbon cables in cryostats: heat sinking is easier; twisted pairs may be used; and miniature multi-way connectors are easily incorporated. Their use is demonstrated in making connections from 131 bolometers in two arrays mounted in a dilution refrigerator at 100 mK. Thermal and electrical properties are discussed, as are other possible applications in cryogenic instruments.

Modeling Woven Polymer Matrix Composites with MAC/GMC

NASA Technical Reports Server (NTRS)

Bednarcyk, Brett A.; Arnold, Steven M. (Technical Monitor)

2000-01-01

NASA's Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC) is used to predict the elastic properties of plain weave polymer matrix composites (PMCs). The traditional one step three-dimensional homogertization procedure that has been used in conjunction with MAC/GMC for modeling woven composites in the past is inaccurate due to the lack of shear coupling inherent to the model. However, by performing a two step homogenization procedure in which the woven composite repeating unit cell is homogenized independently in the through-thickness direction prior to homogenization in the plane of the weave, MAC/GMC can now accurately model woven PMCs. This two step procedure is outlined and implemented, and predictions are compared with results from the traditional one step approach and other models and experiments from the literature. Full coupling of this two step technique with MAC/ GMC will result in a widely applicable, efficient, and accurate tool for the design and analysis of woven composite materials and structures.

Resonance Tests on Glass Reinforced Plastic Composite Panels.

DTIC Science & Technology

1981-04-01

glass -- fibre woven roving and glass - fibre chopped strand mat. BP Cellobond A2785-CV resin was used to bond the glass fibre layers to the foam. A rib was...foam slabs were filled with putty. The differences between the panels were the number of layers of glass fibre used on each side, the density of the...ORGANISATION AERONAUTICAL RESEARCH LABORATORIES MELBOURNE, VICTORIA Structures Technical Memorandum 329 RESONANCE TESTS O GLASS REINFORCED PLASTIC

Forming simulation of woven composite fibers and its influence on structural performance

NASA Astrophysics Data System (ADS)

Divine, Vincent; Beauchesne, Erwan; Roy, Subir; Palaniswamy, Hariharasudhan

2013-12-01

In recent years, the interest in composite material as a replacement for metals has been growing. The automotive industry, in its constant quest for weight reduction, is now seriously considering composite materials as a substitute for sheet metal components to meet future fuel consumption standards. However, composite forming processes are expensive and difficult to control because of its complex composition with fiber and matrix layers or plies and its dependency on many parameters, such as non-linearity of tensile stiffness, effect of shear rate, temperature and friction. Hence, numerical simulation could be a viable approach to predict material behavior during composite forming. The objective of this study is to highlight capabilities of RADIOSS®, a non-linear finite element analysis based structural solver commonly used for stamping and crash analyses, to simulate forming simulation of composite plies made from woven fibers. For validation the well-known double dome model is used with material data published in NUMISHEET'05 proceedings. It is modeled as a woven fabric with an elastic anisotropic fabric material law available in RADIOSS. This material law is able to consider properties along the two directions of anisotropy, warp and weft. The compared result is the shear angle after stamping that is, the variation of angle between warp and weft fibers, at several prescribed points on the ply. The variation of this angle has a strong impact on material characteristics which severely deteriorates when a critical value is reached. Hence, a study on crash simulations is performed, after mapping fibers angles from stamping simulation.

Impact behavior of basalt/epoxy composite: Comparison between flat and twill fabric

NASA Astrophysics Data System (ADS)

Papa, I.; Ricciardi, M. R.; Antonucci, V.; Langella, A.; Lopresto, V.

2018-05-01

Two types of basalt fibre reinforced epoxy laminates were realized by overlapping flat and twill woven basalt fabrics by resin infusion. Rectangular specimens, cut from the panels were impacted at penetration and at increasing energy values, to investigate the damage onset and propagation. A non-destructive technique, Ultrasound testing (UT), was adopted to investigate the internal damage. Despite the difficulties to obtain information by UT method due to the high amount of signal absorbed, the technique, properly calibrated, proved to be very useful in providing information about the presence, the shape and the extent of the delaminations. The results were compared at the aim to investigate the effect of the fiber architecture (textile). The experimental results indicate a similar impact behavior between basalt flat and twill composites but in the case of the twill a minor delaminated area was detected, even if a higher absorbed energy was recorded

Micromechanical Modeling of Woven Metal Matrix Composites

NASA Technical Reports Server (NTRS)

Bednarcyk, Brett A.; Pindera, Marek-Jerzy

1997-01-01

This report presents the results of an extensive micromechanical modeling effort for woven metal matrix composites. The model is employed to predict the mechanical response of 8-harness (8H) satin weave carbon/copper (C/Cu) composites. Experimental mechanical results for this novel high thermal conductivity material were recently reported by Bednarcyk et al. along with preliminary model results. The micromechanics model developed herein is based on an embedded approach. A micromechanics model for the local (micro-scale) behavior of the woven composite, the original method of cells (Aboudi), is embedded in a global (macro-scale) micromechanics model (the three-dimensional generalized method of cells (GMC-3D) (Aboudi). This approach allows representation of true repeating unit cells for woven metal matrix composites via GMC-3D, and representation of local effects, such as matrix plasticity, yarn porosity, and imperfect fiber-matrix bonding. In addition, the equations of GMC-3D were reformulated to significantly reduce the number of unknown quantities that characterize the deformation fields at the microlevel in order to make possible the analysis of actual microstructures of woven composites. The resulting micromechanical model (WCGMC) provides an intermediate level of geometric representation, versatility, and computational efficiency with respect to previous analytical and numerical models for woven composites, but surpasses all previous modeling work by allowing the mechanical response of a woven metal matrix composite, with an elastoplastic matrix, to be examined for the first time. WCGMC is employed to examine the effects of composite microstructure, porosity, residual stresses, and imperfect fiber-matrix bonding on the predicted mechanical response of 8H satin C/Cu. The previously reported experimental results are summarized, and the model predictions are compared to monotonic and cyclic tensile and shear test data. By considering appropriate levels of porosity

Mesoscopic Strains Maps in Woven Composite Laminas During Off-axis Tension

NASA Astrophysics Data System (ADS)

Anzelotti, G.; Nicoletto, G.; Riva, E.

2010-06-01

The mechanics of woven carbon-fiber reinforced plastic (CFRP) composites is influenced by the complex architecture of the reinforcement phase. Computational (i.e. finite element based) approaches have been used increasingly to model not only the global laminate stiffness, but also damage evolution and laminate strength. The modeling combines the identification of the architectural unit cell (UC), the selection of suitable constitutive models of the different phases, the creation of a fine discretization of the UC in finite elements, the application of an incremental solution procedure that solves iteratively for the stresses and strains in the UC, [1]. The experimental validation of computational models is carried out mainly at the macroscopical level, i.e. simulation of the macroscopic stress-strain curve. Damage, however, is a localized, straindependent phenomenon and therefore only accurate strain distribution within the UC (at the mesolevel) can identify critical conditions in terms of damage location, extension and evolution. The validation of computational damage procedures is a key task and full-field optical strain analysis methods appear the ideal instrument. However, only limited examples of direct finte element method (FEM) vs experimental strain correlation are found because of the limited sensitivity and spatial resolution of some techniques and the complexity and applicative difficulty of others. The aim of the present paper is to present the application of the digital image correlation (DIC) technique, [2], to the full-field strain analysis at the mesoscopic level (i.e. within the UC) of a woven CFRP lamina when the direction of loading forms an angle to the material direction. The material under consideration is a woven carbon fiber reinforced epoxy composite. Orthogonal yarns, each made of of several thousand fibers, are woven according the twill-weave architecture is shown in Fig. 1a. Single-ply laminas were manufactured and tested to eliminate

Modelling of the Impact Response of Fibre-Reinforced Composites

DTIC Science & Technology

1990-09-30

observed under tensile loading alone, the damage accumulation process following initial tensile fracture of a fibre tow somewhere within the test specimen...results to be obtained which are not inconsistent with those observed experimentally. Sim- ilarly the delamination process is modelled assuming an...publication either in journals or in conference proceedings. 1 . J. Harding and K. Saka, "The effect of strain rate on the tensile failure of woven reinforced

75 FR 51482 - Woven Electric Blankets From China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-20

... From China Determination On the basis of the record \\1\\ developed in the subject investigation, the... injured by reason of imports from China of woven electric blankets, provided for in subheading 6301.10.00... notification of a preliminary determination by Commerce that imports of woven electric blankets from China were...

Fabricating fiber-reinforced composite posts.

PubMed

Manhart, Jürgen

2011-03-01

Endodontic posts do not increase the strength of the remaining tooth structure in endodontically treated teeth. On the contrary, depending on the post design employed (tapered versus parallel-sided), the root can be weakened relative to the amount of tooth removed during preparation. In many cases, if there has been a high degree of damage to the clinical crown, conservative preparation for an anatomic tapered (biomimetic) post with the incorporation of a ferrule on solid tooth structure is necessary to protect the reaming root structure as well as for the long-term retention of the composite resin core and the definitive restoration. Adhesively luted endodontic posts reinforced with glass or quartz fiber lead to better homogeneous tension distribution when loaded than rigid metal or zirconium oxide ceramic posts. Fiber-reinforced posts also possess advantageous optical properties over metal or metal oxide post systems. The clinician should realize that there are admittedly substantial differences in the mechanical loading capacity of the different fiber-reinforced endodontic posts and should be aware of such differences in order to research and select a suitable post system for use.

Flame retardant treatments of PBI fabric.

NASA Technical Reports Server (NTRS)

Temin, S. C.

1972-01-01

Fabrics knitted or woven from polybenzimidazole (PBI) fibers were treated to reduce flammability in oxygen atmospheres, particularly that of 5 psia oxygen. Bromination to approximately 15% weight gain of such fabrics led to markedly lower burning rates; samples brominated to over 80% weight gain were self-extinguishing in 5 psia oxygen. The loss in tensile strength of fabrics due to bromination was negligible although shrinkage was observed. Free fibers showed negligible losses on bromination. Treatment of PBI fabric with organophosphorus compounds also achieved self-extinguishing character in 5 psia oxygen but the enhanced flameproofing was largely lost on leaching. Reaction with POCl3 in pyridine led to a permanent reduction in flammability.

Application of a Meso-scale Based Ballistic Fabric Model to the Development of Advanced Lightweight Engine Fan Blade-Out Containment Structure

DTIC Science & Technology

2012-09-01

composed of a basic metallic shell structure with a dry Kevlar wrap around it is considered. The fan blade is made of titanium alloy modeled by a Johnson...material. A multilayered Kevlar woven dry fabric structure is wrapped around the thin aluminum shell to form a soft hybrid fan case. A woven fabric material...debris protection fan case composed of a basic metallic shell structure with a dry Kevlar wrap around it is considered. The fan blade is made of titanium

49 CFR 178.518 - Standards for woven plastic bags.

Code of Federal Regulations, 2011 CFR

2011-10-01

... plastic bag; (2) 5H2 for a sift-proof woven plastic bag; and (3) 5H3 for a water-resistant woven plastic... other equally strong method of closure. (3) Bags, sift-proof, 5H2 must be made sift-proof by appropriate...

FILTRATION MODEL FOR COAL FLY ASH WITH GLASS FABRICS

EPA Science Inventory

The report describes a new mathematical model for predicting woven glass filter performance with coal fly ash aerosols from utility boilers. Its data base included: an extensive bench- and pilot-scale laboratory investigation of several dust/fabric combinations; field data from t...

Comparison of Failure Modes in 2-D and 3-D Woven Carbon Phenolic Systems

NASA Technical Reports Server (NTRS)

Rossman, Grant A.; Stackpoole, Mairead; Feldman, Jay; Venkatapathy, Ethiraj; Braun, Robert D.

2013-01-01

failure modes because z-fibers in the through-thickness direction provided extra reinforcement to hold material layers together. Therefore, the benefit of using a 3D weave architecture was shown to alleviate failure modes experienced by a 2D laminate sample of similar material composition. In summary this poster reviews the thermal response performance comparisons drawn between a 3D Woven TPS sample and 2D Carbon Phenolic samples after performing rigorous heating experiments in the mARC facility at NASA Ames. Although the mARC Facility is still in its developmental stages, researchers expect similar trends in failure modes observed from large scale arc jet facilities. This work helps demonstrate the viability of 3D Woven TPSs as a new TPS option for future atmospheric entry missions.

Specimen Design for Sustained Load Testing of Parallel-Laid Glass Fibre Reinforced Plastics.

DTIC Science & Technology

prepared by molding on a sheet of woven glass fabric and stripping this off just before bonding, to leave a roughened surface. The test specimens are 1/2 inch wide strips cut from the laminates. (Author, modified-PL)

Study to investigate design, fabrication and test of low cost concepts for large hybrid composite helicopter fuselage, phase 2

NASA Technical Reports Server (NTRS)

Adams, K. M.; Lucas, J. J.

1977-01-01

The development of a frame/stringer/skin fabrication technique for composite airframe construction was studied as a low cost approach to the manufacturer of larger helicopter airframe components. A center cabin aluminum airframe section of the Sikorsky CH-53D, was selected for evaluation as a composite structure. The design, as developed, is composed of a woven KEVLAR R-49/epoxy skin and graphite/epoxy frames and stringers. The single cure concept is made possible by the utilization of pre-molded foam cores, over which the graphite/epoxy pre-impregnated frame and stringer reinforcements are positioned. Bolted composite channel sections were selected as the optimum joint construction. The applicability of the single cure concept to larger realistic curved airframe sections, and the durability of the composite structure in a realistic spectrum fatigue environment, was described.

Effect of elevated temperature on the tensile strength of Napier/glass-epoxy hybrid reinforced composites

NASA Astrophysics Data System (ADS)

Ridzuan, M. J. M.; Majid, M. S. Abdul; Afendi, M.; Firdaus, A. Z. Ahmad; Azduwin, K.

2017-11-01

The effects of elevated temperature on the tensile strength of Napier/glass-epoxy hybrid reinforced composites and its morphology of fractured surfaces are discussed. Napier/glass-epoxy hybrid reinforced composites were fabricated by using vacuum infusion method by arranging Napier fibres in between sheets of woven glass fibres. Napier and glass fibres were laminated with estimated volume ratios were 24 and 6 vol. %, respectively. The epoxy resin was used as matrix estimated to 70 vol. %. Specimens were tested to failure under tension at a cross-head speed of 1 mm/min using Universal Testing Machine (Instron) with a load cell 100 kN at four different temperatures of RT, 40°C, 60°C and 80°C. The morphology of fractured surface of hybrid composites was investigated by field emission scanning electron microscopy. The result shows reduction in tensile strength at elevated temperatures. The increase in the temperature activates the process of diffusion, and generates critical stresses which cause the damage at first-ply or at the centre of the hybrid plate, as a result lower the tensile strength. The observation of FESEM images indicates that the fracture mode is of evolution of localized damage, from fibre/matrix debonding, matric cracking, delamination and fibre breakage.

Ballistic damage in hybrid composite laminates

NASA Astrophysics Data System (ADS)

Phadnis, Vaibhav A.; Pandya, Kedar S.; Naik, Niranjan K.; Roy, Anish; Silberschmidt, Vadim V.

2015-07-01

Ballistic damage of hybrid woven-fabric composites made of plain-weave E-glass- fabric/epoxy and 8H satin-weave T300 carbon-fabric/epoxy is studied using a combination of experimental tests, microstructural studies and finite-element (FE) analysis. Ballistic tests were conducted with a single-stage gas gun. Fibre damage and delamination were observed to be dominating failure modes. A ply-level FE model was developed, with a fabric-reinforced ply modelled as a homogeneous orthotropic material with capacity to sustain progressive stiffness degradation due to fibre/matrix cracking, fibre breaking and plastic deformation under shear loading. Simulated damage patterns on the front and back faces of fabric-reinforced composite plates provided an insight into their damage mechanisms under ballistic loading.

Meso-macro simulation of the woven fabric local deformation in draping

NASA Astrophysics Data System (ADS)

Iwata, Akira; Inoue, Takuya; Naouar, Naim; Boisse, Philippe; Lomov, Stepan V.

2018-05-01

The paper reports results of such combined meso-macro modelling for a plain weave carbon fabric with spread yarns. The boundary conditions for a local meso-model are taken from the macro draping simulation. The fabric geometry is modelled with WiseTex and transferred to the finite element package. A hyperelastic constitutive model for the yarns (Charmetant - Boisse) is used in the meso-modelling; the model parameters are identified and validated in independent tension, shear, compaction and bending tests of the yarn and the fabric. The simulation reproduces local yarn slippage and buckling, for example, the yarn distortion on the 3D mould corner (see the figure). The simulations are compared with the local fabric distortions observed during draping experiments.

Compression response of thick layer composite laminates with through-the-thickness reinforcement

NASA Technical Reports Server (NTRS)

Farley, Gary L.; Smith, Barry T.; Maiden, Janice

1992-01-01

Compression and compression-after-impact (CAI) tests were conducted on seven different AS4-3501-6 (0/90) 0.64-cm thick composite laminates. Four of the seven laminates had through-the-thickness (TTT) reinforcement fibers. Two TTT reinforcement methods, stitching and integral weaving, and two reinforcement fibers, Kevlar and carbon, were used. The remaining three laminates were made without TTT reinforcements and were tested to establish a baseline for comparison with the laminates having TTT reinforcement. Six of the seven laminates consisted of nine thick layers whereas the seventh material was composed of 46 thin plies. The use of thick-layer material has the potential for reducing structural part cost because of the reduced part count (layers of material). The compression strengths of the TTT reinforced laminates were approximately one half those of the materials without TTT reinforcements. However, the CAI strengths of the TTT reinforced materials were approximately twice those of materials without TTT reinforcements. The improvement in CAI strength is due to an increase in interlaminar strength produced by the TTT reinforcement. Stitched laminates had slightly higher compression and CAI strengths than the integrally woven laminates.

Evaluation of bending rigidity behaviour of ultrasonic seaming on woven fabrics

NASA Astrophysics Data System (ADS)

Şevkan Macit, Ayşe; Tiber, Bahar

2017-10-01

In recent years ultrasonic seaming that is shown as an alternative method to conventional seaming has been investigated by many researchers. In our study, bending behaviour of this alternative method is examined by changing various parameters such as fabric type, seam type, roller type and seaming velocity. For this purpose fifteen types of sewn fabrics were tested according to bending rigidity test standard before and after washing processes and results were evaluated through SPSS statistical analyze programme. Consequently, bending length values of the ultrasonically sewn fabrics are found to be higher than the bending length values of conventionally sewn fabrics and the effects of seam type on bending length are seen statistically significant. Also it is observed that bending length values are in relationship with the rest of the parameters excluding roller type.

Mechanical Characterization and Micromechanical Modeling of Woven Carbon/Copper Composites

NASA Technical Reports Server (NTRS)

Bednarcyk, Brett A.; Pindera, Marek-Jerzy; Ellis, David L.; Miner, Robert V.

1997-01-01

The present investigation examines the in-plane mechanical behavior of a particular woven metal matrix composite (MMC); 8-harness (8H) satin carbon/copper (C/Cu). This is accomplished via mechanical testing as well as micromechanical modeling. While the literature is replete with experimental and modeling efforts for woven and braided polymer matrix composites, little work has been done on woven and braided MMC's. Thus, the development and understanding of woven MMC's is at an early stage. 8H satin C/Cu owes its existence to the high thermal conductivity of copper and low density and thermal expansion of carbon fibers. It is a candidate material for high heat flux applications, such as space power radiator panels. The experimental portion of this investigation consists of monotonic and cyclic tension, compression, and Iosipescu shear tests, as well as combined tension-compression tests. Tests were performed on composite specimens with three copper matrix alloy types: pure Cu, Cu-0.5 weight percent Ti (Cu-Ti), and Cu-0.7 weight percent Cr (Cu-Cr). The small alloying additions are present to promote fiber/matrix interfacial bonding. The analytical modeling effort utilizes an approach in which a local micromechanical model is embedded in a global micromechanical model. This approach differs from previously developed analytical models for woven composites in that a true repeating unit cell is analyzed. However, unlike finite element modeling of woven composites, the geometry is sufficiently idealized to allow efficient geometric discretization and efficient execution.

Development of a Spectra Fabric PASGT-Type Personnel Helmet

DTIC Science & Technology

2015-06-01

ABSTRACT This report documents an effort that took place from October 1987 to September 1989 by AlliedSignal Inc. to develop a resin prepreg ...PASGT) helmet, but with at least 1/3 weight reduction utilizing Spectra® woven fabric prepreg . During the performance period, Allied evaluated

Influence of Fibre Architecture on Impact Damage Tolerance in 3D Woven Composites

NASA Astrophysics Data System (ADS)

Potluri, P.; Hogg, P.; Arshad, M.; Jetavat, D.; Jamshidi, P.

2012-10-01

3D woven composites, due to the presence of through-thickness fibre-bridging, have the potential to improve damage tolerance and at the same time to reduce the manufacturing costs. However, ability to withstand damage depends on weave topology as well as geometry of individual tows. There is an extensive literature on damage tolerance of 2D prepreg laminates but limited work is reported on the damage tolerance of 3D weaves. In view of the recent interest in 3D woven composites from aerospace as well as non-aerospace sectors, this paper aims to provide an understanding of the impact damage resistance as well as damage tolerance of 3D woven composites. Four different 3D woven architectures, orthogonal, angle interlocked, layer-to-layer and modified layer-to-layer structures, have been produced under identical weaving conditions. Two additional structures, Unidirectional (UD) cross-ply and 2D plain weave, have been developed for comparison with 3D weaves. All the four 3D woven laminates have similar order of magnitude of damage area and damage width, but significantly lower than UD and 2D woven laminates. Damage Resistance, calculated as impact energy per unit damage area, has been shown to be significantly higher for 3D woven laminates. Rate of change of CAI strength with impact energy appears to be similar for all four 3D woven laminates as well as UD laminate; 2D woven laminate has higher rate of degradation with respect to impact energy. Undamaged compression strength has been shown to be a function of average tow waviness angle. Additionally, 3D weaves exhibit a critical damage size; below this size there is no appreciable reduction in compression strength. 3D woven laminates have also exhibited a degree of plasticity during compression whereas UD laminates fail instantly. The experimental work reported in this paper forms a foundation for systematic development of computational models for 3D woven architectures for damage tolerance.

Numerically design the injection process parameters of parts fabricated with ramie fiber reinforced green composites

NASA Astrophysics Data System (ADS)

Chen, L. P.; He, L. P.; Chen, D. C.; Lu, G.; Li, W. J.; Yuan, J. M.

2017-01-01

The warpage deformation plays an important role on the performance of automobile interior components fabricated with natural fiber reinforced composites. The present work investigated the influence of process parameters on the warpage behavior of A pillar trim made of ramie fiber (RF) reinforced polypropylene (PP) composites (RF/PP) via numerical simulation with orthogonal experiment method and range analysis. The results indicated that fiber addition and packing pressure were the most important factors affecting warpage. The A pillar trim can achieved the minimum warpage value as of 2.124 mm under the optimum parameters. The optimal process parameters are: 70% percent of the default value of injection pressure for the packing pressure, 20 wt% for the fiber addition, 185 °C for the melt °C for the mold temperature, 7 s for the filling time and 17 s for the packing time.

A Review on the Perforated Impact Energy Absorption of Kenaf Fibres Reinforced Composites

NASA Astrophysics Data System (ADS)

Ismail, Al Emran; Khalid, S. N. A.; Nor, Nik Hisyamudin Muhd

2017-10-01

This paper reviews the potential of mechanical energy absorption of natural fiber reinforced composites subjected to perforated impact. According to literature survey, several research works discussing on the impact performances on natural fiber reinforced composites are available. However, most of these composite fibers are randomly arranged. Due to high demand for sustainable materials, many researches give high attention to enhance the mechanical capability of natural fiber composites especially focused on the fiber architecture. Therefore, it is important to review the progress of impact energy absorption on woven fiber composite in order to identify the research opportunities in the future.

Experimental investigation of effects of stitching orientation on forming behaviors of 2D P-aramid multilayer woven preform

NASA Astrophysics Data System (ADS)

Abtew, Mulat Alubel; Boussu, François; Bruniaux, Pascal; Loghin, Carmen; Cristian, Irina; Chen, Yan; Wang, Lichuan

2018-05-01

In many textile applications stitching process is one of the widely used methods to join the multi-layer fabric plies not only due to its easy applicability and flexible production but also provide structural integrity throughout-the-thickness of materials. In this research, the influences of stitching pattern on various molding characteristics of multi-layer 2D para-aramid plain woven fabrics while deformation was investigated. The fabrics were made of high performance fiber with 930dtex yarn linear density and fabric areal density of 200gm/m2. First, different stitch pattern (orientation) was applied for joining the mentioned multi-layered fabrics keeping other stitching parameters such as stitch gap, stitch thread tension, stitch length, stitch type, stitch thread type etc. constant throughout the study. Then, a pneumatic based molding device with a low speed forming process specially designed for preforming of textile with a predefined hemispherical shape of punch. The result shows that stitching pattern is one of the parameter that influences the different molding behavior and should be consider while molding stitched multi-layer fabrics.

Fabric Organic Electrochemical Transistors for Biosensors.

PubMed

Yang, Anneng; Li, Yuanzhe; Yang, Chenxiao; Fu, Ying; Wang, Naixiang; Li, Li; Yan, Feng

2018-06-01

Flexible fabric biosensors can find promising applications in wearable electronics. However, high-performance fabric biosensors have been rarely reported due to many special requirements in device fabrication. Here, the preparation of organic electrochemical transistors (OECTs) on Nylon fibers is reported. By introducing metal/conductive polymer multilayer electrodes on the fibers, the OECTs show very stable performance during bending tests. The devices with functionalized gates are successfully used as various biosensors with high sensitivity and selectivity. The fiber-based OECTs are woven together with cotton yarns successfully by using a conventional weaving machine, resulting in flexible and stretchable fabric biosensors with high performance. The fabric sensors show much more stable signals in the analysis of moving aqueous solutions than planar devices due to a capillary effect in fabrics. The fabric devices are integrated in a diaper and remotely operated by using a mobile phone, offering a unique platform for convenient wearable healthcare monitoring. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fiber Reinforced Polyester Resins Polymerized by Microwave Source

NASA Astrophysics Data System (ADS)

Visco, A. M.; Calabrese, L.; Cianciafara, P.; Bonaccorsi, L.; Proverbio, E.

2007-12-01

Polyester resin based composite materials are widely used in the manufacture of fiberglass boats. Production time of fiberglass laminate components could be strongly reduced by using an intense energy source as well as microwaves. In this work a polyester resin was used with 2% by weight of catalyst and reinforced with chopped or woven glass fabric. Pure resin and composite samples were cured by microwaves exposition for different radiation times. A three point bending test was performed on all the cured samples by using an universal testing machine and the resulting fracture surfaces were observed by means of scanning electron microscopy (SEM). The results of mechanical and microscopy analyses evidenced that microwave activation lowers curing time of the composite while good mechanical properties were retained. Microwaves exposition time is crucial for mechanical performance of the composite. It was evidenced that short exposition times suffice for resin activation while long exposure times cause fast cross linking and premature matrix fracture. Furthermore high-radiation times induce bubbles growth or defects nucleation within the sample, decreasing composite performance. On the basis of such results microwave curing activation of polyester resin based composites could be proposed as a valid alternative method for faster processing of laminated materials employed for large-scale applications.

24 CFR 200.946 - Building product standards and certification program for exterior finish and insulation systems...

Code of Federal Regulations, 2012 CFR

2012-04-01

...) ASTM C-1186-91 Standard Specification for Flat Non-Asbestos Fiber-Cement Sheets. (v) ASTM D 579-90 Standard Specification for Greige Woven Glass Fabrics. (vi) ASTM D 3273-86—(Reapproved 1991) Standard Test... Glass Fiber Reinforcing Mesh for Use in Exterior Insulation and Finish Systems (EIFS), Class PB. (xv...

24 CFR 200.946 - Building product standards and certification program for exterior finish and insulation systems...

Code of Federal Regulations, 2014 CFR

2014-04-01

...) ASTM C-1186-91 Standard Specification for Flat Non-Asbestos Fiber-Cement Sheets. (v) ASTM D 579-90 Standard Specification for Greige Woven Glass Fabrics. (vi) ASTM D 3273-86—(Reapproved 1991) Standard Test... Glass Fiber Reinforcing Mesh for Use in Exterior Insulation and Finish Systems (EIFS), Class PB. (xv...

24 CFR 200.946 - Building product standards and certification program for exterior finish and insulation systems...

Code of Federal Regulations, 2013 CFR

2013-04-01

...) ASTM C-1186-91 Standard Specification for Flat Non-Asbestos Fiber-Cement Sheets. (v) ASTM D 579-90 Standard Specification for Greige Woven Glass Fabrics. (vi) ASTM D 3273-86—(Reapproved 1991) Standard Test... Glass Fiber Reinforcing Mesh for Use in Exterior Insulation and Finish Systems (EIFS), Class PB. (xv...

Fabrication of a First Article Lightweight Composite Technology Demonstrator - Exospine

DTIC Science & Technology

2014-01-01

core, (b) 0/90, and (c) ± 45 ply cuts of ACG-MTM 45-1/CF0526 prepreg fabric...onboard diagnostics. 2. Experimental 2.1 Materials Plain woven carbon fiber/epoxy prepreg and a low-density foam core were provided to ARL for the...fabrication of the exospine technology demonstrator by UD-CCM. The prepreg was ACG - MTM∗ 45-1/CF0526 and has a cured ply thickness of 0.201 mm. It is

Formability Analysis of Bamboo Fabric Reinforced Poly (Lactic) Acid Composites

PubMed Central

M. R., Nurul Fazita; Jayaraman, Krishnan; Bhattacharyya, Debes

2016-01-01

Poly (lactic) acid (PLA) composites have made their way into various applications that may require thermoforming to produce 3D shapes. Wrinkles are common in many forming processes and identification of the forming parameters to prevent them in the useful part of the mechanical component is a key consideration. Better prediction of such defects helps to significantly reduce the time required for a tooling design process. The purpose of the experiment discussed here is to investigate the effects of different test parameters on the occurrence of deformations during sheet forming of double curvature shapes with bamboo fabric reinforced-PLA composites. The results demonstrated that the domes formed using hot tooling conditions were better in quality than those formed using cold tooling conditions. Wrinkles were more profound in the warp direction of the composite domes compared to the weft direction. Grid Strain Analysis (GSA) identifies the regions of severe deformation and provides useful information regarding the optimisation of processing parameters. PMID:28773662

Fabrication, mechanical characterization of pineapple leaf fiber (PALF) reinforced vinylester hybrid composites

NASA Astrophysics Data System (ADS)

Yogesh, M.; Rao, A. N. Hari

2018-04-01

Natural fibre based composites are under intensive study due to their eco friendly nature and peculiar properties. The advantage of natural fibres is their continuous supply, easy and safe handling, and biodegradable nature. Although natural fibres exhibit admirable physical and mechanical properties, it varies with the plant source, species, geography, and so forth. Pineapple leave fibre (PALF) is one of the abundantly available waste materials in India and has not been studied yet. The work has been carried out to fabrication and study the mechanical characterization of Pineapple Leaf fiber reinforced Vinylester composites filled with different particulate fillers. These results are compared with those of a similar set of glass fiber reinforced Vinylester composites filled with same particulate fillers. It is evident that the density values for Pineapple leaf fiber (PALF) - Vinylester composites increase with the particulate filler content and void fractions in these composites also increase. The test results show that with the presence of particulate fillers, micro hardness of the PALF-Vinylester composites has improved. Among all the composites under this investigation, the maximum hardness value is recorded for PALF-Vinylester composite filled with 20 wt% alumina. In this investigation the maximum value of ILSS has been recorded for the PALF-Vinylester composite with 20 wt% of Flyash.

Green application of flame retardant cotton fabric using supercritical carbon dioxide

USDA-ARS?s Scientific Manuscript database

Due to its environmentally benign character, supercritical carbon dioxide (scCO2) is considered in green chemistry as a substitute for organic solvents in chemical reactions. In this poster, an innovative approach for preparation of flame retardant woven and nonwoven fabrics were obtained by utiliz...

Long-Term Isothermal Aging Effects on Carbon Fabric-Reinforced PMR-15 Composites: Compression Strength

NASA Technical Reports Server (NTRS)

Bowles, Kenneth J.; Roberts, Gary D.; Kamvouris, John E.

1996-01-01

A study was conducted to determine the effects of long-term isothermal thermo-oxidative aging on the compressive properties of T-650-35 fabric reinforced PMR-15 composites. The temperatures that were studied were 204, 260, 288, 316, and 343 C. Specimens of different geometries were evaluated. Cut edge-to-surface ratios of 0.03 to 0.89 were fabricated and aged. Aging times extended to a period in excess of 15,000 hours for the lower temperature runs. The unaged and aged specimens were tested in compression in accordance with ASTM D-695. Both thin and thick (plasma) specimens were tested. Three specimens were tested at each time/temperature/geometry condition. The failure modes appeared to be initiated by fiber kinking with longitudinal, interlaminar splitting. In general, it appears that the thermo-oxidative degradation of the compression strength of the composite material may occur by both thermal (time-dependent) and oxidative (weight-loss) mechanisms. Both mechanisms appear to be specimen-thickness dependent.

Processes for fabricating composite reinforced material

DOEpatents

Seals, Roland D.; Ripley, Edward B.; Ludtka, Gerard M.

2015-11-24

A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

Particle-Based Geometric and Mechanical Modelling of Woven Technical Textiles and Reinforcements for Composites

NASA Astrophysics Data System (ADS)

Samadi, Reza

Technical textiles are increasingly being engineered and used in challenging applications, in areas such as safety, biomedical devices, architecture and others, where they must meet stringent demands including excellent and predictable load bearing capabilities. They also form the bases for one of the most widespread group of composite materials, fibre reinforced polymer-matrix composites (PMCs), which comprise materials made of stiff and strong fibres generally available in textile form and selected for their structural potential, combined with a polymer matrix that gives parts their shape. Manufacturing processes for PMCs and technical textiles, as well as parts and advanced textile structures must be engineered, ideally through simulation, and therefore diverse properties of the textiles, textile reinforcements and PMC materials must be available for predictive simulation. Knowing the detailed geometry of technical textiles is essential to predicting accurately the processing and performance properties of textiles and PMC parts. In turn, the geometry taken by a textile or a reinforcement textile is linked in an intricate manner to its constitutive behaviour. This thesis proposes, investigates and validates a general numerical tool for the integrated and comprehensive analysis of textile geometry and constitutive behaviour as required toward engineering applications featuring technical textiles and textile reinforcements. The tool shall be general with regards to the textiles modelled and the loading cases applied. Specifically, the work aims at fulfilling the following objectives: 1) developing and implementing dedicated simulation software for modelling textiles subjected to various load cases; 2) providing, through simulation, geometric descriptions for different textiles subjected to different load cases namely compaction, relaxation and shear; 3) predicting the constitutive behaviour of the textiles undergoing said load cases; 4) identifying parameters

Studies of in-plane shear behaviour of braided composite reinforcements

NASA Astrophysics Data System (ADS)

Xiao, Shenglei; Wang, Peng; Soulat, Damien; Legrand, Xavier; Gao, Hang

2018-05-01

Braided fabrics are wildly used as textile reinforcements to manufacture the advanced composite parts. The braids can be used as two-dimensional reinforcement to manufacture the composite reinforced by braided fabrics. This study proposed the analysis on the in-plane shear behavior of braided structure fabric. Firstly, the geometric criterion and analytical model have been developed. Secondly, E-glass fibres reinforced braided fabrics have been performed in bias-extension tests to verify the analytical model. The conclusion was that the change of dimension ratio could influence on the shear load /displacement behavior significantly owing to the increasing area for sustaining load with an increase in ratio. However, varying dimension ratio r in axial direction had nearly no effect on shear moment/angle behavior. And the experimental and theoretical results had a good agreement.

Chairside Fabrication of an All-Ceramic Partial Crown Using a Zirconia-Reinforced Lithium Silicate Ceramic

PubMed Central

Pabel, Anne-Kathrin; Rödiger, Matthias

2016-01-01

The chairside fabrication of a monolithic partial crown using a zirconia-reinforced lithium silicate (ZLS) ceramic is described. The fully digitized model-free workflow in a dental practice is possible due to the use of a powder-free intraoral scanner and the computer-aided design/computer-assisted manufacturing (CAD/CAM) of the restorations. The innovative ZLS material offers a singular combination of fracture strength (>370 Mpa), optimum polishing characteristics, and excellent optical properties. Therefore, this ceramic is an interesting alternative material for monolithic restorations produced in a digital workflow. PMID:27042362

Shear damage mechanisms in a woven, Nicalon-reinforced ceramic-matrix composite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keith, W.P.; Kedward, K.T.

The shear response of a Nicalon-reinforced ceramic-matrix composite was investigated using Iosipescu tests. Damage was characterized by X-ray, optical, and SEM techniques. The large inelastic strains which were observed were attributed to rigid body sliding of longitudinal blocks of material. These blocks are created by the development and extension of intralaminar cracks and ply delaminations. This research reveals that the debonding and sliding characteristics of the fiber-matrix interface control the shear strength, strain softening, and cyclic degradation of the material.

Non-woven PGA/PVA fibrous mesh as an appropriate scaffold for chondrocyte proliferation.

PubMed

Rampichová, M; Koštáková, E; Filová, E; Prosecká, E; Plencner, M; Ocheretná, L; Lytvynets, A; Lukáš, D; Amler, E

2010-01-01

Non-woven textile mesh from polyglycolic acid (PGA) was found as a proper material for chondrocyte adhesion but worse for their proliferation. Neither hyaluronic acid nor chitosan nor polyvinyl alcohol (PVA) increased chondrocyte adhesion. However, chondrocyte proliferation suffered from acidic byproducts of PGA degradation. However, the addition of PVA and/or chitosan into a wet-laid non-woven textile mesh from PGA improved chondrocyte proliferation seeded in vitro on the PGA-based composite scaffold namely due to a diminished acidification of their microenvironment. This PVA/PGA composite mesh used in combination with a proper hydrogel minimized the negative effect of PGA degradation without dropping positive parameters of the PGA wet-laid non-woven textile mesh. In fact, presence of PVA and/or chitosan in the PGA-based wet-laid non-woven textile mesh even advanced the PGA-based wet-laid non-woven textile mesh for chondrocyte seeding and artificial cartilage production due to a positive effect of PVA in such a scaffold on chondrocyte proliferation.

Shear behavior of thermoformed woven-textile thermoplastic prepregs: An analysis combining bias-extension test and X-ray microtomography

NASA Astrophysics Data System (ADS)

Gassoumi, M.; Rolland du Roscoat, S.; Casari, P.; Dumont, P. J. J.; Orgéas, L.; Jacquemin, F.

2017-10-01

Thermoforming allows the manufacture of structural parts for the automotive and aeronautical domains using long fiber thermoplastic prepregs with short cycle times. During this operation, several sheets of molten prepregs are stacked and subjected to large macroscale strains, mainly via in-plane shear, out-of-plane consolidation or dilatation, and bending of the fibrous reinforcement. These deformation modes and the related meso and microstructure evolutions are still poorly understood. However, they can drastically alter the end-use macroscale properties of fabricated parts. To better understand these phenomena, bias extension tests were performed using specimens made of several stacked layers of glass woven fabrics and polyamide matrix. The macroscale shear behavior of these prepregs was investigated at various temperatures. A multiscale analysis of deformed samples was performed using X-ray microtomography images of the deformed specimens acquired at two different spatial resolutions. The low-resolution images were used to analyze the deformation mechanisms and the structural characteristics of prepregs at the macroscale and bundle scales. It was possible to analyze the 3D shapes of deformed samples and, in particular, the spatial variations of their thickness so as to quantify the out-of-plane dilatancy or consolidation phenomena induced by the in-plane shear of prepregs. At a lower scale, the analysis of the high-resolution images showed that these mechanisms were accompanied by the growth of pores and the deformation of fiber bundles. The orientation of the fiber bundles and its through-thickness evolution were measured along the weft and warp directions in the deformed samples, allowing the relevance of geometrical models currently used to analyze bias extension tests to be discussed. Results can be used to enhance the current rheological models for the prediction of thermoforming of thermoplastic prepregs.

Personnel occupied woven envelope robot power

NASA Technical Reports Server (NTRS)

Wessling, F. C.

1988-01-01

The Personnel Occupied Woven Envelope Robot (POWER) concept has evolved over the course of the study. The goal of the project was the development of methods and algorithms for solid modeling for the flexible robot arm.

Numerical simulation of multi-layered textile composite reinforcement forming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, P.; Hamila, N.; Boisse, P.

2011-05-04

One important perspective in aeronautics is to produce large, thick or/and complex structural composite parts. The forming stage presents an important role during the whole manufacturing process, especially for LCM processes (Liquid Composites Moulding) or CFRTP (Continuous Fibre Reinforcements and Thermoplastic resin). Numerical simulations corresponding to multi-layered composite forming allow the prediction for a successful process to produce the thick parts, and importantly, the positions of the fibres after forming to be known. This paper details a set of simulation examples carried out by using a semi-discrete shell finite element made up of unit woven cells. The internal virtual workmore » is applied on all woven cells of the element taking into account tensions, in-plane shear and bending effects. As one key problem, the contact behaviours of tool/ply and ply/ply are described in the numerical model. The simulation results not only improve our understanding of the multi-layered composite forming process but also point out the importance of the fibre orientation and inter-ply friction during formability.« less

Characterization of surface modified polyester fabric.

PubMed

Joseph, Roy; Shelma, R; Rajeev, A; Muraleedharan, C V

2009-12-01

Woven polyethylene terephthalate (PET) fabric has been used in the construction of vascular grafts and sewing ring of prosthetic heart valves. In an effort to improve haemocompatibility and tissue response to PET fabric, a fluoropolymer, polyvinylidine fluoride (PVDF), was coated on PET fabric by dip coating technique. The coating was found to be uniform and no significant changes occurred on physical properties such as water permeability and burst strength. Cell culture cytotoxicity studies showed that coated PET was non-cytotoxic to L929 fibroblast cell lines. In vitro studies revealed that coating improved haemocompatibility of PET fabric material. Coating reduced platelet consumption of PET fabric by 50%. Upon surface modification leukocyte consumption of PET was reduced by 24%. About 60% reduction in partial thromboplastin time (PTT) observed when PET was coated with PVDF. Results of endothelial cell proliferation studies showed that surface coating did not have any substantial impact on cell proliferation. Overall results indicate that coating has potential to improve haemocompatibility of PET fabric without affecting its mechanical performance.

All-fabric-based wearable self-charging power cloth

NASA Astrophysics Data System (ADS)

Song, Yu; Zhang, Jinxin; Guo, Hang; Chen, Xuexian; Su, Zongming; Chen, Haotian; Cheng, Xiaoliang; Zhang, Haixia

2017-08-01

We present an all-fabric-based self-charging power cloth (SCPC), which integrates a fabric-based single-electrode triboelectric generator (STEG) and a flexible supercapacitor. To effectively scavenge mechanical energy from the human motion, the STEG could be directly woven among the cloth, exhibiting excellent output capability. Meanwhile, taking advantage of fabric structures with a large surface-area and carbon nanotubes with high conductivity, the wearable supercapacitor exhibits high areal capacitance (16.76 mF/cm2) and stable cycling performance. With the fabric configuration and the aim of simultaneously collecting body motion energy by STEG and storing in supercapacitors, such SCPC could be easily integrated with textiles and charged to nearly 100 mV during the running motion within 6 min, showing great potential in self-powered wearable electronics and smart cloths.

The effect of reinforcement on the tear properties of flexible circuits

NASA Astrophysics Data System (ADS)

Acton, A. E.

The tear properties of Kapton flexible circuitry are very poor. To better understand the properties of flex circuits and how to reinforce them, four different reinforcing materials were applied to a typical flex circuit and the tear properties were measured. Teflon film, nylon fabric, glass fabric and Kevlar fabric were all laminated to a flex circuit with Pyralux (a Dupont tradename) adhesive. The fabrics were laminated in both a 0/90 and a + or - 45 configuration. Five tests wereperformed, Graves, crescent, trousers, tensile and single edge notch (SEN). Of the four materials used for reinforcement, Kevlar clearly showed the greatest overall improvement in tear properties. However, Kevlar also provided the greatest processing difficulties. All of the reinforced circuits had an increase in thickness which resulted in an unacceptable loss of flexibility.

Long Term Displacement Data of Woven Fabric Webbings Under Constant Load for Inflatable Structures

NASA Technical Reports Server (NTRS)

Kenner, Winfred S.; Jones, Thomas C.; Doggett, William R.; Lucy, Melvin H.; Grondin, Trevor A.; Whitley, Karen S.; Duncan, Quinton; Plant, James V.

2014-01-01

Inflatable modules for space applications offer weight and launch volume savings relative to current metallic modules. Limited data exist on the creep behavior of the restraint layer of inflatable modules. Long-term displacement and strain data of two high strength woven fabric webbings, Kevlar and Vectran, under constant load is presented. The creep behavior of webbings is required by designers to help determine service life parameters of inflatable modules. Four groups of different webbings with different loads were defined for this study. Group 1 consisted of 4K Kevlar webbings loaded to 33% ultimate tensile strength and 6K Vectran webbings loaded to 27% ultimate tensile strength, group 2 consisted of 6K Kevlar webbings loaded to 40% and 43% ultimate tensile strength, and 6K Vectran webbings loaded to 50% ultimate tensile strength, group 3 consisted of 6K Kevlar webbings loaded to 52% ultimate tensile strength and 6K Vectran webbings loaded to 60% ultimate tensile strength, and group 4 consisted of 12.5K Kevlar webbings loaded to 22% ultimate tensile strength, and 12.5K Vectran webbings loaded to 22% ultimate tensile strength. The uniquely designed test facility, hardware, displacement measuring devices, and test data are presented. Test data indicate that immediately after loading all webbings stretch an inch or more, however as time increases displacement values significantly decrease to fall within a range of several hundredth of an inch over the remainder of test period. Webbings in group 1 exhibit near constant displacements and strains over a 17-month period. Data acquisition was suspended after the 17th month, however webbings continue to sustain load without any local webbing damage as of the 21st month of testing. Webbings in group 2 exhibit a combination of initial constant displacement and subsequent increases in displacement rates over a 16-month period. Webbings in group 3 exhibit steady increases in displacement rates leading to webbing failure

75 FR 7244 - Narrow Woven Ribbons with Woven Selvedge from the People's Republic of China: Preliminary...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-18

.... (``Guangzhou Complacent''); Ningbo Huarui Import & Export Co., Ltd.; Ningbo Jinfeng Thread & Ribbon Co. Ltd... limited to nylon, polyester, rayon, polypropylene, and polyethylene teraphthalate), metal threads and/or... 13) or rubber thread; (4) narrow woven ribbons of a kind used for the manufacture of typewriter or...

Carbon Nanotubes Reinforced Composites for Biomedical Applications

PubMed Central

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

2014-01-01

This review paper reported carbon nanotubes reinforced composites for biomedical applications. Several studies have found enhancement in the mechanical properties of CNTs-based reinforced composites by the addition of CNTs. CNTs reinforced composites have been intensively investigated for many aspects of life, especially being made for biomedical applications. The review introduced fabrication of CNTs reinforced composites (CNTs reinforced metal matrix composites, CNTs reinforced polymer matrix composites, and CNTs reinforced ceramic matrix composites), their mechanical properties, cell experiments in vitro, and biocompatibility tests in vivo. PMID:24707488

Carbon nanotubes reinforced composites for biomedical applications.

PubMed

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

2014-01-01

This review paper reported carbon nanotubes reinforced composites for biomedical applications. Several studies have found enhancement in the mechanical properties of CNTs-based reinforced composites by the addition of CNTs. CNTs reinforced composites have been intensively investigated for many aspects of life, especially being made for biomedical applications. The review introduced fabrication of CNTs reinforced composites (CNTs reinforced metal matrix composites, CNTs reinforced polymer matrix composites, and CNTs reinforced ceramic matrix composites), their mechanical properties, cell experiments in vitro, and biocompatibility tests in vivo.

Heat sealable, flame and abrasion resistant coated fabric

NASA Technical Reports Server (NTRS)

Tschirch, R. P.; Sidman, K. R. (Inventor)

1983-01-01

Flame retardant, abrasion resistant elastomeric compositions are disclosed which are comprised of thermoplastic polyurethane polymer and flame retarding amounts of a filler selected from decabromodiphenyloxide and antimony oxide in a 3:1 weight ratio, and decabromodiphenyloxide, antimony oxide, and ammonium polyphosphate in a 3:1:3 weight ratio respectively. Heat sealable coated fabrics employing such elastomeric compositions as coating film are produced by dissolving the elastomeric composition to form a solution, casting the solution onto a release paper and drying it to form an elastomeric film. The film is then bonded to a woven, knitted, or felted fabric.

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

USDA-ARS?s Scientific Manuscript database

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

NERVA turbopump bearing retainer fabrication on nonmetallic retainer

NASA Technical Reports Server (NTRS)

Accinelli, J. B.

1972-01-01

The need for a low-wear, lightweight, high strength bearing retainer material with a radiation degradation threshold of 10 to the 9th power rads (C) prompted development of nonmetallic reinforced polymers of the following types: (1) polybenzimidazole, (2) polyimide, and (3) polyquinoxaline. Retainers were machined from tubular laminates (billets), including reinforcement by either glass or graphite fabric or filament. Fabrication of billets involves hot preimpregnation of the reinforcement fabric or filament with polymer followed by wrapping this prepreg over a heated mandrel to form a tube with the required thickness and length.

A non-orthogonal material model of woven composites in the preforming process

DOE PAGES

Zhang, Weizhao; Ren, Huaqing; Liang, Biao; ...

2017-05-04

Woven composites are considered as a promising material choice for lightweight applications. An improved non-orthogonal material model that can decouple the strong tension and weak shear behaviour of the woven composite under large shear deformation is proposed for simulating the preforming of woven composites. The tension, shear and compression moduli in the model are calibrated using the tension, bias-extension and bending experiments, respectively. The interaction between the composite layers is characterized by a sliding test. The newly developed material model is implemented in the commercial finite element software LS-DYNA® and validated by a double dome study.

75 FR 50991 - Antidumping Duty Order: Certain Woven Electric Blankets From the People's Republic of China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-18

...: Certain Woven Electric Blankets From the People's Republic of China AGENCY: Import Administration... electric blankets (``woven electric blankets'') from the People's Republic of China (``PRC''). FOR FURTHER... Certain Woven Electric Blankets From the People's Republic of China: Final Determination of Sales at Less...

Engineering fabrics in transportation construction

NASA Astrophysics Data System (ADS)

Herman, S. C.

1983-11-01

The following areas are discussed: treatments for reduction of reflective cracking of asphalt overlays on jointed-concrete pavements in Georgia; laboratory testing of fabric interlayers for asphalt concrete paving: interim report; reflection cracking models: review and laboratory evaluation of engineering fabrics; optimum-depth method for design of fabric-reinforced unsurfaced roads; dynamic test to predict field behavior of filter fabrics used in pavement subdrains; mechanism of geotextile performance in soil-fabric systems for drainage and erosion control; permeability tests of selected filter fabrics for use with a loess-derived alluvium; geotextile filter criteria; use of fabrics for improving the placement of till on peat foundation; geotextile earth-reinforced retaining wall tests: Glenwood Canyon, Colorado; New York State Department of Transportation's experience and guidelines for use of geotextiles; evaluation of two geotextile installations in excess of a decade old; and, long-term in situ properties of geotextiles.

Self-healing of low-velocity impact damage in glass fabric/epoxy composites using an epoxy-mercaptan healing agent

NASA Astrophysics Data System (ADS)

Chao Yuan, Yan; Ye, Yueping; Zhi Rong, Min; Chen, Haibin; Wu, Jingshen; Qiu Zhang, Ming; Qin, Shi Xiang; Yang, Gui Cheng

2011-01-01

Self-healing woven glass fabric-reinforced epoxy composite laminates were made by embedding epoxy- and mercaptan-loaded microcapsules. After being subjected to low-velocity impact, the laminates were able to heal the damage in an autonomic way at room temperature. The healing-induced reduction in the damaged areas was visualized using a scanning acoustic microscope. The rate of damage area reduction, which is closely related to the effect of crack rehabilitation and mechanical recovery, is a function of impact energy, content and size of the healing microcapsules. Minor damage, such as microcracks in the matrix, can be completely repaired by the healing system without manual intervention, including external pressure. Microcapsules with larger size and/or higher concentration are propitious for delivering more healing agent to cracked portions, while imposition of lateral pressure on damaged specimens forces the separated faces to approach each other. Both can improve the rate of damage area reduction in the case of severe damage.

75 FR 46911 - Certain Woven Electric Blankets from the People's Republic of China: Amended Final Determination...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-04

... Blankets from the People's Republic of China: Amended Final Determination of Sales at Less Than Fair Value... than fair value (``LTFV'') in the antidumping investigation of certain woven electric blankets (``woven electric blankets'') from the People's Republic of China (``PRC''). See Certain Woven Electric Blankets...

Wet-Lay Process - A Novel Approach to Scalable Fabrication of Tissue Scaffolds and Reinforcement Membranes

NASA Astrophysics Data System (ADS)

Wood, Andrew

Fibrous materials received a great deal of interest in the fields of tissue engineering and regenerative medicine due to the beneficial cell-interactions and tunable properties for various biomedical applications. These materials are highly advantageous as they provide a large surface area for cellular attachment, proliferation, high porosity values for cellular in-growth, and the ability to modify the membrane to achieve desired responses to both mechanical loading as well as environmental stimuli. A prominent method currently used to fabricate such membranes is electrospinning which uses electrostatic forces to produce fibers on the range of nanometers giving them high morphological saliency to the native extra cellular matrix (ECM). These fibers are also advantageous mechanically with strength and flexibility due to their larger aspect ratio when compared to larger diameter micro/macro fibers. While this spinning technique has many advantages and has seen the most quantity of research in recent years, it does have its own set of drawbacks. Among them is the use cytotoxic solvents during processing which must be fully removed before implantation. In addition, since the fiber produced have smaller diameters, the resulting average pore-size of the scaffold is decreased which in turn hinders cellular penetration into the bulk scaffold. In this work, we have proposed and characterized a novel method called wet-lay process for the rapid fabrication of fibrous membranes for tissue scaffolds. Wet-laying is a method common to textiles and paper industry but unexplored for tissue scaffolds. Short fibers are first suspended in an aqueous bath and homogeneously dispersed using shear force. After draining away the aqueous solution, a nonwoven fibro-porous membrane is deposited onto the draining screen. The implementation of wet-laid membranes into weak hydrogel matrices has shown a reinforcement effect for the composite. Further analyses were carried out to determine the

Sapphire reinforced alumina matrix composites

NASA Technical Reports Server (NTRS)

Jaskowiak, Martha H.; Setlock, John A.

1994-01-01

Unidirectionally reinforced A1203 matrix composites have been fabricated by hot pressing. Approximately 30 volume % of either coated or uncoated sapphire fiber was used as reinforcement. Unstabilized ZrO2 was applied as the fiber coating. Composite mechanical behavior was analyzed both after fabrication and after additional heat treatment. The results of composite tensile tests were correlated with fiber-matrix interfacial shear strengths determined from fiber push-out tests. Substantially higher strength and greater fiber pull-out were observed for the coated fiber composites for all processing conditions studied. The coated fiber composites retained up to 95% and 87% of their as-fabricated strength when heat treated at 14000C for 8 or 24 hours, respectively. Electron microscopy analysis of the fracture surfaces revealed extensive fiber pull-out both before and after heat treatment.

Dynamic and static strength of an implant-supported overdenture model reinforced with metal and nonmetal strengtheners.

PubMed

Rached, Rodrigo Nunes; de Souza, Evelise Machado; Dyer, Scott R; Ferracane, Jack Liborio

2011-11-01

Fractures of overdentures occur in the denture base through the abutments. The purpose of this study was to evaluate the effect of reinforcements and the space available for their placement on the dynamic and static loading capacity of a simulated implant-supported overdenture model. Rhomboidal (6 × 6 × 25 mm) test specimens (n=8), made with an acrylic resin and containing 2 metal O-ring capsules, were reinforced with braided stainless steel bar (BS), stainless steel mesh (SM), unidirectional E-glass fiber (GF), E-glass mesh (GM), woven polyethylene braids (PE), or polyaramid fibers (PA). Two distinct spaces for reinforcement placement were investigated: a 2.5 mm and a 1 mm space. Control groups consisted of nonreinforced specimens. Specimens were thermocycled (5°C and 55°C, 5,000 cycles) and then subjected to a 100,000 cyclic load regime. Unbroken specimens were then loaded until failure. The number of failures under fatigue (f) and static load (s) were compared with the Chi-Square test, while static load means were compared with the Kruskal-Wallis test (α=.05). The number of failures (f:s) of GF (0:16), PE (0:16), and PA (0:16) differed significantly from the control group (8:8) and SM (4:12) (P=.037 and P=.025, respectively). For the 2.5 mm space group, these same reinforcements also exhibited higher static load means than the control (P=.016, P=.003, and P=.003, respectively); under static load, no significant differences were detected between the reinforced groups and the control for the 1.0 mm space group (P=1.0). E-glass fibers, woven polyethylene braids, and polyaramid fibers withstood the fatigue regime and increased the flexural strength of the implant-supported overdenture model. The spaces available for reinforcement did not affect the dynamic strength or the static loading capacity of the implant-supported overdenture model. Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

75 FR 53642 - Narrow Woven Ribbons With Woven Selvedge From the People's Republic of China: Countervailing Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-01

... any color, style, pattern, or weave construction, including but not limited to single-faced satin..., styles, patterns, and/or weave constructions; Have been subjected to, or composed of materials that have... DEPARTMENT OF COMMERCE International Trade Administration [C-570-953] Narrow Woven Ribbons With...

Processing and Characterization of Liquid-Phase Sintered NiTi Woven Structures

NASA Astrophysics Data System (ADS)

Erdeniz, Dinc; Weidinger, Ryan P.; Sharp, Keith W.; Dunand, David C.

2018-03-01

Porous NiTi is of interest for bone implants because of its unique combination of biocompatibility (encouraging osseointegration), high strength (to prevent fracture), low stiffness (to reduce stress shielding), and shape memory or superelasticity (to deploy an implant). A promising method for creating NiTi structures with regular open channels is via 3D weaving of NiTi wires. This paper presents a processing method to bond woven NiTi wire structures at contact points between wires to achieve structural integrity: (i) a slurry consisting of a blend of NiTi and Nb powders is deposited on the surface of the NiTi wires after the weaving operation; (ii) the powders are melted to create a eutectic liquid phase which collects at contact points; and (iii) the liquid is solidified and binds the NiTi woven structures. The bonded NiTi wire structures exhibited lower transformation temperatures compared to the as-woven NiTi wires because of Nb diffusion into the NiTi wires. A bonded woven sample was deformed in bending and showed near-complete recovery up to 6% strain and recovered nearly half of the deformation up to 19% strain.

CONTINUED ASSESSMENT OF A HIGH-VELOCITY FABRIC FILTRATION SYSTEM USED TO CONTROL FLY ASH EMISSIONS

EPA Science Inventory

The report gives results of a full-scale investigation of the performance of a variety of filter media, to provide technical and economic information under high-velocity conditions (high gas/cloth ratio). The fly ash emission studies demonstrated that woven fiberglass fabrics and...

Investigation on mechanical properties of basalt composite fabrics (experiment study)

NASA Astrophysics Data System (ADS)

Talebi Mazraehshahi, H.; Zamani, H.

2010-06-01

To fully appreciate the role and application of composite materials to structures, correct understanding of mechanical behaviors required for selection of optimum material. Fabric reinforced composites are composed of a matrix that is reinforced with pliable fabric, glass fabric is most popular reinforcement for different application specially in aircraft structure, although other fabric material are also used. At this study new fabric material called basalt with epoxy resin introduced and mechanical behaviors of this material investigated from view point of testing. For this study two type of fabric with different thickness used. Comparison between this composite reinforcement with popular reinforcement as carbon, glass, kevlar performed. To determine mechanical properties of epoxy based basalt fabric following test procedure performed : 1). Tensile testing according to ASTM D3039 in 0° and 90° direction to find ultimate strength in tension and shear, modulus of elasticity, elangation and ultimate strain. 2). Compression testing according to EN 2850 ultimate compression strength and maximum deformation under compression loading. 3). Shear testing according to ASTM D3518-94 to find in plane shear response of polymer matrix composites materials. 4). Predict flexural properties of sandwich construction which manufactured from basalt facing with PVC foam core according to ASTM C393-94. Material strength properties must be based on enough tests of material to meet the test procedure specifications [1]. For this reason six specimens were manufactured for testing and the tests were performed on them using an INSTRON machine model 5582. In the study, the effect of percent of resin in basalt reinforced composite was investigated. Also the weights of the ballast based composites with different percent of resin were measured with conventional composites. As the weight is an important parameter in aerospace industry when the designer wants to replace one material with

75 FR 41808 - Narrow Woven Ribbons With Woven Selvedge From the People's Republic of China: Final Determination...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-19

... may: Also include natural or other non-man-made fibers; Be of any color, style, pattern, or weave..., twill, jacquard, or a combination of two or more colors, styles, patterns, and/or weave constructions... DEPARTMENT OF COMMERCE International Trade Administration [A-570-952] Narrow Woven Ribbons With...

Evaluation of mechanical properties of hybrid fiber (hemp, jute, kevlar) reinforced composites

NASA Astrophysics Data System (ADS)

Suresha, K. V.; Shivanand, H. K.; Amith, A.; Vidyasagar, H. N.

2018-04-01

In today's world composites play wide role in all the engineering fields. The reinforcement of composites decides the properties of the material. Natural fiber composites compared to synthetic fiber possesses poor mechanical properties. The solution for this problem is to use combination of natural fiber and synthetic fiber. Hybridization helps to improve the overall mechanical properties of the material. In this study, hybrid reinforced composites of Hemp fabric/Kevlar fabric/Epoxy and Jute fabric/ Kevlar fabric/Epoxy composites are fabricated using Simple hand layup technique followed by Vacuum bagging process. Appropriate test methods as per standards and guidelines are followed to analyze mechanical behavior of the composites. The mechanical characteristics like tensile, compression and flexural properties of the hybrid reinforced composites are tested as per the ASTM standards by series of tensile test; compression test and three point bending tests were conducted on the hybrid composites. A quantitative relationship between the Hemp fabric/Kevlar fabric/Epoxy and Jute/ Kevlar fabric/Epoxy has been established with constant thickness.

Comparison of resin film infusion, resin transfer molding, and consolidation of textile preforms for primary aircraft structure

NASA Technical Reports Server (NTRS)

Suarez, J.; Dastin, S.

1992-01-01

Innovative design concepts and cost effective fabrication processes were developed for damage tolerant primary structures that can perform at a design ultimate strain level of 6000 micro inch/inch. Attention focused on the use of textile high performance fiber reinforcement concepts that provide improved damage tolerance and out-of-plane load capability, low cost resin film infusion (RFI) and resin transfer molding (RTM) processes, and thermoplastic forming concepts. The fabrication of wing 'Y' spars by four different materials and/or processes methods is described: fabricated using IM7 angle interlock 0 to 90 deg woven preforms with + or - 45 deg plies stitched with Toray high strength graphite thread and processed using RFI and 3501-6 epoxy; fabricated using G40-800 knitted/stitched preforms and processed using RFI and 3501-6 epoxy; fabricated using G40-800 knitted/stitched preforms using RTM and Tactix 123/H41 epoxy; and fabricated preforms using AS4(6K)/PEEK 150 g commingled angle interlock 0 to 90 deg woven preforms with + or - 45 deg commingled plies stitched using high strength graphite thread and processed by consolidation. Structural efficiency, processability, and acquisition cost are compared.

Life Limiting Behavior in Interlaminar Shear of Continuous Fiber-Reinforced Ceramic Matrix Composites at Elevated Temperatures

NASA Technical Reports Server (NTRS)

Choi, Sung R.; Calomino, Anthony M.; Bansal, Narottam P.; Verrilli, Michael J.

2006-01-01

Interlaminar shear strength of four different fiber-reinforced ceramic matrix composites was determined with doublenotch shear test specimens as a function of test rate at elevated temperatures ranging from 1100 to 1316 C in air. Life limiting behavior, represented as interlaminar shear strength degradation with decreasing test rate, was significant for 2-D crossplied SiC/MAS-5 and 2-D plain-woven C/SiC composites, but insignificant for 2-D plain-woven SiC/SiC and 2-D woven Sylramic (Dow Corning, Midland, Michigan) SiC/SiC composites. A phenomenological, power-law delayed failure model was proposed to account for and to quantify the rate dependency of interlaminar shear strength of the composites. Additional stress rupture testing in interlaminar shear was conducted at elevated temperatures to validate the proposed model. The model was in good agreement with SiC/MAS-5 and C/SiC composites, but in poor to reasonable agreement with Sylramic SiC/SiC. Constant shear stress-rate testing was proposed as a possible means of life prediction testing methodology for ceramic matrix composites subjected to interlaminar shear at elevated temperatures when short lifetimes are expected.

On Porosity Formation in Metal Matrix Composites Made with Dual-Scale Fiber Reinforcements Using Pressure Infiltration Process

NASA Astrophysics Data System (ADS)

Etemadi, Reihaneh; Pillai, Krishna M.; Rohatgi, Pradeep K.; Hamidi, Sajad Ahmad

2015-05-01

This is the first such study on porosity formation phenomena observed in dual-scale fiber preforms during the synthesis of metal matrix composites (MMCs) using the gas pressure infiltration process. In this paper, different mechanisms of porosity formation during pressure infiltration of Al-Si alloys into Nextel™ 3D-woven ceramic fabric reinforcements (a dual-porosity or dual-scale porous medium) are studied. The effect of processing conditions on porosity content of the ceramic fabric infiltrated by the alloys through the gas PIP (PIP stands for "Pressure Infiltration Process" in which liquid metal is injected under pressure into a mold packed with reinforcing fibers.) is investigated. Relative density (RD), defined as the ratio of the actual MMC density and the density obtained at ideal 100 pct saturation of the preform, was used to quantify the overall porosity. Increasing the infiltration temperature led to an increase in RD due to reduced viscosity of liquid metal and enhanced wettability leading to improved feedability of the liquid metal. Similarly, increasing the infiltration pressure led to enhanced penetration of fiber tows and resulted in higher RD and reduced porosity. For the first time, the modified Capillary number ( Ca*), which is found to predict formation of porosity in polymer matrix composites quite well, is employed to study porosity in MMCs made using PIP. It is observed that in the high Ca* regime which is common in PIP, the overall porosity shows a strong downward trend with increasing Ca*. In addition, the effect of matrix shrinkage on porosity content of the samples is studied through using a zero-shrinkage Al-Si alloy as the matrix; usage of this alloy as the matrix led to a reduction in porosity content.

Dynamics of house dust mite transfer in modern clothing fabrics.

PubMed

Clarke, David; Burke, Daniel; Gormally, Michael; Byrne, Miriam

2015-04-01

Clothing is largely presumed as being the mechanism by which house dust mites are distributed among locations in homes, yet little research to date has investigated the capacity with which various clothing fabric types serve as vectors for their accumulation and dispersal. Although previous research has indicated that car seats provide a habitat for mite populations, dynamics involved in the transfer of mites to clothing via car seat material is still unknown. To investigate the dynamics involved in the transfer of house dust mites from car seat material to modern clothing fabrics. A total of 480 samples of car seat material were seeded with mites and subjected to contact with plain woven cotton, denim, and fleece. Contact forces equivalent to the mass of a typical adult and child were administered for different durations of contact. Mean transfer efficiencies of mites from car seat material to receiving clothing fabrics ranged from 7.2% to 19.1%. Fabric type, mite condition (live or dead), and the force applied all revealed a significant effect (P < .001 for each variable) on the transfer efficiency of house dust mites from seeded material to receiving fabrics, whereas duration of contact revealed no effect (P = .20). In particular, mean numbers of mites transferred to fleece (compared with denim and plain woven cotton) were greater for each treatment. These findings indicate that clothing type can have important implications for the colonization of other biotopes by house dust mites, with potential for affecting an individuals' personal exposure to dust mite allergens. Copyright © 2015 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

40 CFR 430.120 - Applicability; description of the tissue, filter, non-woven, and paperboard from purchased pulp...

Code of Federal Regulations, 2011 CFR

2011-07-01

... tissue, filter, non-woven, and paperboard from purchased pulp subcategory. 430.120 Section 430.120... PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Tissue, Filter, Non-Woven, and Paperboard From Purchased Pulp Subcategory § 430.120 Applicability; description of the tissue, filter, non-woven, and...

40 CFR 430.120 - Applicability; description of the tissue, filter, non-woven, and paperboard from purchased pulp...

Code of Federal Regulations, 2014 CFR

2014-07-01

... tissue, filter, non-woven, and paperboard from purchased pulp subcategory. 430.120 Section 430.120... (CONTINUED) THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Tissue, Filter, Non-Woven, and Paperboard From Purchased Pulp Subcategory § 430.120 Applicability; description of the tissue, filter, non-woven...

40 CFR 430.120 - Applicability; description of the tissue, filter, non-woven, and paperboard from purchased pulp...

Code of Federal Regulations, 2012 CFR

2012-07-01

... tissue, filter, non-woven, and paperboard from purchased pulp subcategory. 430.120 Section 430.120... (CONTINUED) THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Tissue, Filter, Non-Woven, and Paperboard From Purchased Pulp Subcategory § 430.120 Applicability; description of the tissue, filter, non-woven...

40 CFR 430.120 - Applicability; description of the tissue, filter, non-woven, and paperboard from purchased pulp...

Code of Federal Regulations, 2013 CFR

2013-07-01

... tissue, filter, non-woven, and paperboard from purchased pulp subcategory. 430.120 Section 430.120... (CONTINUED) THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Tissue, Filter, Non-Woven, and Paperboard From Purchased Pulp Subcategory § 430.120 Applicability; description of the tissue, filter, non-woven...

40 CFR 430.120 - Applicability; description of the tissue, filter, non-woven, and paperboard from purchased pulp...

Code of Federal Regulations, 2010 CFR

2010-07-01

... tissue, filter, non-woven, and paperboard from purchased pulp subcategory. 430.120 Section 430.120... PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY Tissue, Filter, Non-Woven, and Paperboard From Purchased Pulp Subcategory § 430.120 Applicability; description of the tissue, filter, non-woven, and...

Woven-grid sealed quasi-bipolar lead-acid battery construction and fabricating method

NASA Technical Reports Server (NTRS)

Rippel, Wally E. (Inventor)

1989-01-01

A quasi-bipolar lead-acid battery construction includes a plurality of bipolar cells disposed in side-by-side relation to form a stack, and a pair of monoplanar plates at opposite ends of the stack, the cell stack and monopolar plates being contained within a housing of the battery. Each bipolar cell is loaded with an electrolyte and composed of a bipolar electrode plate and a pair of separator plates disposed on opposite sides of the electrode plate and peripherally sealed thereto. Each bipolar electrode plate is composed of a partition sheet and two bipolar electrode elements folded into a hairpin configuration and applied over opposite edges of the partition sheet so as to cover the opposite surfaces of the opposite halves thereof. Each bipolar electrode element is comprised of a woven grid with a hot-melt strip applied to a central longitudinal region of the grid along which the grid is folded into the hairpin configuration, and layers of negative and positive active material pastes applied to opposite halves of the grid on opposite sides of the central hot-melt strip. The grid is made up of strands of conductive and non-conductive yarns composing the respective transverse and longitudinal weaves of the grid. The conductive yarn has a multi-stranded glass core surrounded and covered by a lead sheath, whereas the non-conductive yarn has a multi-stranded glass core surrounded and covered by a thermally activated sizing.

Fabrication and tribological response of aluminium 6061 hybrid composite reinforced with bamboo char and boron carbide micro-fillers

NASA Astrophysics Data System (ADS)

Chethan, K. N.; Pai, Anand; Keni, Laxmikant G.; Singhal, Ashish; Sinha, Shubham

2018-02-01

Metal matrix composites (MMCs) have a wide scope of industrial applications and triumph over conventional materials due to their light weight, higher specific strength, good wear resistance and lower coefficient of thermal expansion. The present study aims at establishing the feasibility of using Bamboo charcoal particulate and boron carbide as reinforcements in Al-6061 alloy matrix and to investigate their effect on the wear of composites taking into consideration the interfacial adhesion of the reinforcements in the alloy. Al-6061 alloy was chosen as a base metallic alloy matrix. Sun-dried bamboo canes were used for charcoal preparation with the aid of a muffle furnace. The carbon content in the charcoal samples was determined by EDS (energy dispersive spectroscopy). In present study, stir casting technique was used to prepare the samples with 1%, 2%, and 3% weight of bamboo charcoal and boron carbide with Al-6061. The fabricated composites were homogenised at 570°C for 6 hours and cooled at room temperature. Wear studies were carried out on the specimens with different speed and loads. It was found that wear rate and coefficient of friction decreased with increase in the reinforcement content.

Static and Dynamic Mechanical Properties of Graphene Oxide-Incorporated Woven Carbon Fiber/Epoxy Composite

NASA Astrophysics Data System (ADS)

Adak, Nitai Chandra; Chhetri, Suman; Kim, Nam Hoon; Murmu, Naresh Chandra; Samanta, Pranab; Kuila, Tapas

2018-03-01

This study investigates the synergistic effects of graphene oxide (GO) on the woven carbon fiber (CF)-reinforced epoxy composites. The GO nanofiller was incorporated into the epoxy resin with variations in the content, and the CF/epoxy composites were manufactured using a vacuum-assisted resin transfer molding process and then cured at 70 and 120 °C. An analysis of the mechanical properties of the GO (0.2 wt.%)/CF/epoxy composites showed an improvement in the tensile strength, Young's modulus, toughness, flexural strength and flexural modulus by 34, 20, 83, 55 and 31%, respectively, when compared to the CF/epoxy composite. The dynamic mechanical analysis of the composites exhibited an enhancement of 56, 114 and 22% in the storage modulus, loss modulus and damping capacity (tan δ), respectively, at its glass transition temperature. The fiber-matrix interaction was studied using a Cole-Cole plot analysis.

Crash-Energy Absorbing Composite Structure and Method of Fabrication

NASA Technical Reports Server (NTRS)

Kellas, Sotiris (Inventor); Carden, Huey D. (Inventor)

1996-01-01

A stand-alone, crash-energy absorbing structure and fabrication method are provided. A plurality of adjoining rigid cells are each constructed of resin-cured fiber reinforcement and are arranged in a geometric configuration. The fiber reinforcement can be in the form of a fabric or braided fibers wrapped about a core that is either left in place or removed from the ultimate cured structure. The geometric configuration of cells is held together with more fiber reinforcement (in the form of fabric or braided fibers) in order to integrate the cells in the geometric configuration. The additional fiber reinforcement is resin-cured to the cells. Curing of the cells and ultimate structure can occur in a single step. In applications where post-crash integrity is necessary, ductile fibers can be used to integrate the cells in the geometric configuration. The novelty of the present invention is that simple fabrication techniques are used to create structures that can be formed in a variety of net stable shapes without additional reinforcement and can withstand combined loading while crushing in a desired direction.

Wear properties of 10 vol.% silicon carbide particulate-reinforced aluminum composite fabricated by powder injection molding

NASA Astrophysics Data System (ADS)

Patcharawit, T.; Ngeekoh, A.; Chuankrekkul, N.

2017-09-01

Wear properties of aluminum matrix composites reinforced with silicon carbide particulate of 10 vol.% addition was investigated in as-sintered and heat-treated conditions under varying loads at -5, -25, -45 and -65N using a ball on flat type of wear test. The composite was fabricated by powder injection molding and sintering at 650 °C for 3 hours. Solution treatment was carried out at 550 °C for 2 hours followed by age-hardening at 160 °C for 6 hours. SEM and XRD results indicated Al and SiCp are present as matrix and reinforcement, while AlN, Al2Cu and Mg2Si were also detected. Further precipitation of Al2Cu and Mg2Si in heat-treated samples promoted maximum macro and micro Vickers hardness values, which were achieved at 161 and 157 Hv respectively. Wear weight loss increased with increasing minus load level. The coefficient of friction was found in the range of 0.042-0.048. Wear mechanisms were determined as the combination of abrasive, adhesion and oxidation.

As-Fabricated Reinforced Carbon/Carbon Characterized

NASA Technical Reports Server (NTRS)

Jacobson, Nathan S.; Calomino, Anthony M.; Webster, Neal

2004-01-01

Reinforced carbon/carbon (RCC) is a critical material for the space shuttle orbiter. It is used on the wing leading edge and the nose cap, where maximum temperatures are reached on reentry. The existing leading-edge system is a single-plate RCC composite construction with a wall thickness of approximately 1/4 in., making it a prime reliant protection scheme for vehicle operation.

Thermo-Mechanical Behaviour of Flax-Fibre Reinforced Epoxy Laminates for Industrial Applications

PubMed Central

Pitarresi, Giuseppe; Tumino, Davide; Mancuso, Antonio

2015-01-01

The present work describes the experimental mechanical characterisation of a natural flax fibre reinforced epoxy polymer composite. A commercial plain woven quasi-unidirectional flax fabric with spun-twisted yarns is employed in particular, as well as unidirectional composite panels manufactured with three techniques: hand-lay-up, vacuum bagging and resin infusion. The stiffness and strength behaviours are investigated under both monotonic and low-cycle fatigue loadings. The analysed material has, in particular, shown a typical bilinear behaviour under pure traction, with a knee yield point occurring at a rather low stress value, after which the material tensile stiffness is significantly reduced. In the present work, such a mechanism is investigated by a phenomenological approach, performing periodical loading/unloading cycles, and repeating tensile tests on previously “yielded” samples to assess the evolution of stiffness behaviour. Infrared thermography is also employed to measure the temperature of specimens during monotonic and cyclic loading. In the first case, the thermal signal is monitored to correlate departures from the thermoelastic behaviour with the onset of energy loss mechanisms. In the case of cyclic loading, the thermoelastic signal and the second harmonic component are both determined in order to investigate the extent of elastic behaviour of the material. PMID:28793643

In-Plane Shear Testing of Medium and High Modulus Woven Graphite Fiber Reinforced/Polyimide Composites

NASA Technical Reports Server (NTRS)

Gentz, M.; Armentrout, D.; Rupnowski, P.; Kumosa, L.; Shin, E.; Sutter, J. K.; Kumosa, M.

2004-01-01

Iosipescu shear tests were performed at room temperature and at 316 C (600 F) o woven composites with either M40J or M60J graphite fibers and PMR-II-50 polyimide resin matrix. The composites were tested as supplied and after thermo-cycling, with the thermo-cycled composites being tested under dry and wet conditions. Acoustic emission (AE) was monitored during the room and high temperature Iosipescu experiments. The shear stresses at the maximum loads and the shear stresses at the significant onset of AE were determined for the composites as function of temperature and conditioning. The combined effects of thermo-cycling and moisture on the strength and stiffness properties of the composites were evaluated. It was determined that the room and high temperature shear stresses at the maximum loads were unaffected by conditioning. However, at room temperature the significant onset of AE was affected by conditioning; the thermal conditioned wet specimens showed the highest shear stress at the onset of AE followed by thermal-conditioned and then as received specimens. Also, at igh temperature the significant onset of AE occurred in some specimens after the maximum load due to the viscoelastoplastic nature of the matrix material.

Evaluation of failure criterion for graphite/epoxy fabric laminates

NASA Technical Reports Server (NTRS)

Tennyson, R. C.; Wharram, G. E.

1985-01-01

The development and application of the tensor polynomial failure criterion for composite laminate analysis is described. Emphasis is given to the fabrication and testing of Narmco Rigidite 5208-WT300, a plain weave fabric of Thornel 300 Graphite fibers impregnated with Narmco 5208 Resin. The quadratic-failure criterion with F sub 12=0 provides accurate estimates of failure stresses for the graphite/epoxy investigated. The cubic failure criterion was recast into an operationally easier form, providing design curves that can be applied to laminates fabricated from orthotropic woven fabric prepregs. In the form presented, no interaction strength tests are required, although recourse to the quadratic model and the principal strength parameters is necessary. However, insufficient test data exist at present to generalize this approach for all prepreg constructions, and its use must be restricted to the generic materials and configurations investigated to date.

Fabrication of aluminum-carbon composites

NASA Technical Reports Server (NTRS)

Novak, R. C.

1973-01-01

A screening, optimization, and evaluation program is reported of unidirectional carbon-aluminum composites. During the screening phase both large diameter monofilament and small diameter multifilament reinforcements were utilized to determine optimum precursor tape making and consolidation techniques. Difficulty was encountered in impregnating and consolidating the multifiber reinforcements. Large diameter monofilament reinforcement was found easier to fabricate into composites and was selected to carry into the optimization phase in which the hot pressing parameters were refined and the size of the fabricated panels was scaled up. After process optimization the mechanical properties of the carbon-aluminum composites were characterized in tension, stress-rupture and creep, mechanical fatigue, thermal fatigue, thermal aging, thermal expansion, and impact.

Dispenser printed electroluminescent lamps on textiles for smart fabric applications

NASA Astrophysics Data System (ADS)

de Vos, Marc; Torah, Russel; Tudor, John

2016-04-01

Flexible electroluminescent (EL) lamps are fabricated onto woven textiles using a novel dispenser printing process. Dispenser printing utilizes pressurized air to deposit ink onto a substrate through a syringe and nozzle. This work demonstrates the first use of this technology to fabricate EL lamps. The luminance of the dispenser printed EL lamps is compared to screen-printed EL lamps, both printed on textile, and also commercial EL lamps on polyurethane film. The dispenser printed lamps are shown to have a 1.5 times higher luminance than the best performing commercially available lamp, and have a comparable performance to the screen-printed lamps.

Processing and Properties of SiC/MoSi2-SiC Composites Fabricated by Melt Infiltration

NASA Technical Reports Server (NTRS)

Bhatt, Ramakrishna T.; Hebsur, Mohan G.

2000-01-01

Hi-Nicalon SiC fiber reinforced MoSi2-SiC matrix composites (SiC/MoSi2-SiC) have been fabricated by the melt infiltration approach. The composite consists of approximately 60 vol%, 2-D woven BN/SiC coated Hi-Nicalon SiC fibers and approximately 40 vol% MoSi2-SiC matrix. The room temperature tensile properties and thermal conductivity of the SiC/MoSi2-SiC composites were measured and compared with those of the melt infiltrated SiC/SiC composites. The influence oi fiber architecture on tensile properties was also evaluated. Results indicate that the primary modulus, stress corresponding to deviation from linearity, and transverse thermal conductivity values for the SiC/MoSi2-SiC composites are significantly lower than those for the SiC/SiC composites. Microcracking of the matrix due to the large difference in thermal expansion between MoSi2 and SiC appears to be the reason for the lower matrix dominated properties of SiC/MoSi2-SiC composites.

Hybrid carbon-glass fiber/toughened epoxy thick composites subject to drop-weight and ballistic impacts

NASA Astrophysics Data System (ADS)

Sevkat, Ercan

The goals of this study are to investigate the low velocity and ballistic impact response of thick-section hybrid fiber composites at room temperature. Plain-woven S2-Glass and IM7 Graphite fabrics are chosen as fiber materials reinforcing the SC-79 epoxy. Four different types of composites consisting of alternating layers of glass and graphite woven fabric sheets are considered. Tensile tests are conducted using 98 KN (22 kip) MTS testing machine equipped with environmental chamber. Low-velocity impact tests are conducted using an Instron-Dynatup 8250 impact test machine equipped with an environmental chamber. Ballistic impact tests are performed using helium pressured high-speed gas-gun. Tensile tests results were used to define the material behavior of the hybrid and non-hybrid composites in Finite Element modeling. The low velocity and ballistic impact tests showed that hybrid composites performance was somewhere between non-hybrid woven composites. Using woven glass fabrics as outer skin improved the impact performance of woven graphite composite. However hybrid composites are prone to delamination especially between dissimilar layers. The ballistic limit velocity V50 hybrid composites were higher that of woven graphite composite and lower than that of woven glass composite. Both destructive cross-sectional micrographs and nondestructive ultrasonic techniques are used to evaluate the damage created by impact. The Finite Element code LS-DYNA is chosen to perform numerical simulations of low velocity and ballistic impact on thick-section hybrid composites. The damage progression in these composites shows anisotropic nonlinearity. The material model to describe this behavior is not available in LS-DYNA material library. Initially, linear orthotropic material with damage (Chan-Chan Model) is employed to simulate some of the experimental results. Then, user-defined material subroutine is incorporated into LS-DYNA to simulate the nonlinear behavior. The

Continuous unidirectional fiber reinforced composites: Fabrication and testing

NASA Technical Reports Server (NTRS)

Weber, M. D.; Spiegel, F. X.; West, Harvey A.

1994-01-01

The study of the anisotropic mechanical properties of an inexpensively fabricated composite with continuous unidirectional fibers and a clear matrix was investigated. A method has been developed to fabricate these composites with aluminum fibers and a polymer matrix. These composites clearly demonstrate the properties of unidirectional composites and cost less than five dollars each to fabricate.

CEMCAN Software Enhanced for Predicting the Properties of Woven Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Murthy, Pappu L. N.; Mital, Subodh K.; DiCarlo, James A.

2000-01-01

Major advancements are needed in current high-temperature materials to meet the requirements of future space and aeropropulsion structural components. Ceramic matrix composites (CMC's) are one class of materials that are being evaluated as candidate materials for many high-temperature applications. Past efforts to improve the performance of CMC's focused primarily on improving the properties of the fiber, interfacial coatings, and matrix constituents as individual phases. Design and analysis tools must take into consideration the complex geometries, microstructures, and fabrication processes involved in these composites and must allow the composite properties to be tailored for optimum performance. Major accomplishments during the past year include the development and inclusion of woven CMC micromechanics methodology into the CEMCAN (Ceramic Matrix Composites Analyzer) computer code. The code enables one to calibrate a consistent set of constituent properties as a function of temperature with the aid of experimentally measured data.

Deployable robotic woven wire structures and joints for space applications

NASA Technical Reports Server (NTRS)

Shahinpoor, MO; Smith, Bradford

1991-01-01

Deployable robotic structures are basically expandable and contractable structures that may be transported or launched to space in a compact form. These structures may then be intelligently deployed by suitable actuators. The deployment may also be done by means of either airbag or spring-loaded typed mechanisms. The actuators may be pneumatic, hydraulic, ball-screw type, or electromagnetic. The means to trigger actuation may be on-board EPROMS, programmable logic controllers (PLCs) that trigger actuation based on some input caused by the placement of the structure in the space environment. The actuation may also be performed remotely by suitable remote triggering devices. Several deployable woven wire structures are examined. These woven wire structures possess a unique form of joint, the woven wire joint, which is capable of moving and changing its position and orientation with respect to the structure itself. Due to the highly dynamic and articulate nature of these joints the 3-D structures built using them are uniquely and highly expandable, deployable, and dynamic. The 3-D structure naturally gives rise to a new generation of deployable three-dimensional spatial structures.

Basalt fiber reinforced polymer composites: Processing and properties

NASA Astrophysics Data System (ADS)

Liu, Qiang

A high efficiency rig was designed and built for in-plane permeability measurement of fabric materials. A new data derivation procedure to acquire the flow fluid pattern in the experiment was developed. The measurement results of the in-plane permeability for basalt twill 31 fabric material showed that a high correlation exists between the two principal permeability values for this fabric at 35% fiber volume fraction. This may be the most important scientific contribution made in this thesis. The results from radial measurements corresponded quite well with those from Unidirectional (UD) measurements, which is a well-established technique. No significant differences in mechanical properties were found between basalt fabric reinforced polymer composites and glass composites reinforced by a fabric of similar weave pattern. Aging results indicate that the interfacial region in basalt composites may be more vulnerable to environmental damage than that in glass composites. However, the basalt/epoxy interface may have been more durable than the glass/epoxy interface in tension-tension fatigue because the basalt composites have significantly longer fatigue life. In this thesis, chapter I reviews the literature on fiber reinforced polymer composites, with concentration on permeability measurement, mechanical properties and durability. Chapter II discusses the design of the new rig for in-plane permeability measurement, the new derivation procedure for monitoring of the fluid flow pattern, and the permeability measurement results. Chapter III compares the mechanical properties and durability between basalt fiber and glass fiber reinforced polymer composites. Lastly, chapter IV gives some suggestions and recommendations for future work.

Fabrication of selectively functionalized-graphene reinforced copper phthalocyanine nanocomposites with low dielectric loss and high dielectric constant

NASA Astrophysics Data System (ADS)

Wang, Zicheng; Wei, Renbo; Liu, Xiaobo

2017-01-01

A novel kind of selectively functionalized-graphene reinforced copper phthalocyanine (RGO-O-CuPc) nanocomposites was successfully fabricated through a facile and effective three-step method, involving preferential surficial modification and reduction of graphene oxide (GO) sheets, and followed by incorporating with CuPc via in situ polymerization. The results of SEM, AFM, XPS, FTIR, XRD and UV-vis confirmed that GO was effectively surficial functionalized by a ring-open covalent reaction between amino in 3-aminophenoxyphthalonitrile (3-APN) and epoxy groups on the GO sheets, and partly reduced back to graphene under solvothermal conditions. And the RGO-O-CuPc was successfully fabricated by self-assembling of CuPc molecule on graphene sheets via in situ polymerization. As a consequence, the selective surface functionalization and solvothermal reduction of GO facilitated the improvement in the dielectric constant and AC conductivity, and the decrease in the dielectric loss of the graphene/CuPc nanocomposites.

Fabrication and properties of SiNO continuous fiber reinforced BN wave-transparent composites

NASA Astrophysics Data System (ADS)

Cao, F.; Fang, Z.; Chen, F.; Shen, Q.; Zhang, C.

2012-06-01

SiNO continuous fiber reinforced boron nitride (BN) wave-transparent composites (SiNO f /BN) have been fabricated by a precursor infiltration pyrolysis (PIP) method using borazine as the precursor. The densification behavior, microstructures, mechanical properties, and dielectric properties of the composites have been investigated. After four PIP cycles, the density of the composites had increased from 1.1 g·cm-3 to 1.81 g·cm-3. A flexural strength of 128.9 MPa and an elastic modulus of 23.5 GPa were achieved. The obtained composites have relatively high density and the fracture faces show distinct fiber pull-out and interface de-bonding features. The dielectric properties of the SiNO f /BN composites, including the dielectric constant of 3.61 and the dielectric loss angle tangent of 5.7×10-3, are excellent for application as wave-transparent materials.

Tensile properties of interwoven hemp/PET (Polyethylene Terephthalate) epoxy hybrid composites

NASA Astrophysics Data System (ADS)

Ahmad, M. A. A.; Majid, M. S. A.; Ridzuan, M. J. M.; Firdaus, A. Z. A.; Amin, N. A. M.

2017-10-01

This paper describes the experimental investigation of the tensile properties of interwoven Hemp/PET hybrid composites. The effect of hybridization of hemp (warp) with PET fibres (weft) on tensile properties was of interest. Hemp and PET fibres were selected as the reinforcing material while epoxy resin was chosen as the matrix. The interwoven Hemp/PET fabric was used to produce hybrid composite using a vacuum infusion process. The tensile test was conducted using Universal Testing Machine in accordance to the ASTM D638. The tensile properties of the interwoven Hemp/PET hybrid composite were then compared with the neat woven hemp/epoxy composite. The results show that the strength of hemp/PET with the warp direction was increased by 8% compared to the neat woven hemp composite. This enhancement of tensile strength was due to the improved interlocking structure of interwoven Hemp/PET hybrid fabric.

Characterization and modeling of tensile behavior of ceramic woven fabric composites

NASA Technical Reports Server (NTRS)

Kuo, Wen-Shyong; Chen, Wennei Y.; Parvizi-Majidi, Azar; Chou, Tsu-Wei

1991-01-01

This paper examines the tensile behavior of SiC/SiC fabric composites. In the characterization effort, the stress-strain relation and damage evolution are studied with a series of loading and unloading tensile test experiments. The stress-strain relation is linear in response to the initial loading and becomes nonlinear when loading exceeds the proportional limit. Transverse cracking has been observed to be a dominant damage mode governing the nonlinear deformation. The damage is initiated at the inter-tow pores where fiber yarns cross over each other. In the modeling work, the analysis is based upon a fiber bundle model, in which fiber undulation in the warp and fill directions and gaps among fiber yarns have been taken into account. Two limiting cases of fabric stacking arrangements are studied. Closed form solutions are obtained for the composite stiffness and Poisson's ratio. Transverse cracking in the composite is discussed by applying a constant failure strain criterion.

Structural coloration of chitosan coated cellulose fabrics by electrostatic self-assembled poly (styrene-methyl methacrylate-acrylic acid) photonic crystals.

PubMed

Yavuz, Gönül; Zille, Andrea; Seventekin, Necdet; Souto, Antonio P

2018-08-01

The structural coloration of a chitosan-coated woven cotton fabric obtained by glutaraldehyde-stabilized deposition of electrostatic self-assembled monodisperse and spherically uniform (250 nm) poly (styrene-methyl methacrylate-acrylic acid) photonic crystal nanospheres (P(St-MMA-AA)) was investigated. Bright iridescent coatings displaying different colors in function of the viewing angle were obtained. The SEM, diffuse reflectance spectroscopy, TGA, DSC and FTIR analyses confirm the presence of structural color and the glutaraldehyde and chitosan ability to provide durable chemical bonding between cotton fabric and photonic crystal (PCs) coating with the highest degradation temperature and the lowest enthalpy. The coatings are characterized by a mixture of face-centered cubic and hexagonal close-packed arrays alternating random packing regions. For the first time a cost-efficient structural coloration with high washing and light fastness using self-assembled P(St-MMA-AA) photonic crystals was successfully developed onto woven cotton fabric using chitosan and/or glutaraldehyde as stabilizing agent opening new strategies for the development of dye-free coloration of textiles. Copyright © 2018 Elsevier Ltd. All rights reserved.

Study to investigate design, fabrication and test of low cost concepts for large hybrid composite helicopter fuselage, phase 1

NASA Technical Reports Server (NTRS)

Adams, K. M.; Lucas, J. J.

1975-01-01

The development of a frame/stringer/skin fabrication technique for composite airframe construction was studied as a low cost approach to the manufacture of large helicopter airframe components. A center cabin aluminum airframe section of the Sikorsky CH-53D helicopter was selected for evaluation as a composite structure. The design, as developed, is composed of a woven KEVLAR-49/epoxy skin and graphite/epoxy frames and stringers. To support the selection of this specific design concept a materials study was conducted to develop and select a cure compatible graphite and KEVLAR-49/epoxy resin system, and a foam system capable of maintaining shape and integrity under the processing conditions established. The materials selected were, Narmco 5209/Thornel T-300 graphite, Narmco 5209/KEVLAR-49 woven fabric, and Stathane 8747 polyurethane foam. Eight specimens were fabricated, representative of the frame, stringer, and splice joint attachments. Evaluation of the results of analysis and test indicate that design predictions are good to excellent except for some conservatism of the complex frame splice.

16 CFR 1609.1 - Text of the Flammable Fabrics Act of 1953, as amended in 1954.

Code of Federal Regulations, 2014 CFR

2014-01-01

... be worn by individuals except hats, gloves, and footwear: Provided, however, That such hats do not... form an integral part of another garment: And provided further, That such footwear does not consist of...) The term fabric means any material (other than fiber, filament, or yarn) woven, knitted, felted, or...

16 CFR 1609.1 - Text of the Flammable Fabrics Act of 1953, as amended in 1954.

Code of Federal Regulations, 2012 CFR

2012-01-01

... be worn by individuals except hats, gloves, and footwear: Provided, however, That such hats do not... form an integral part of another garment: And provided further, That such footwear does not consist of...) The term fabric means any material (other than fiber, filament, or yarn) woven, knitted, felted, or...

Durability of carbon fiber reinforced shape memory polymer composites in space

NASA Astrophysics Data System (ADS)

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

2016-04-01

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

Methods of making wind turbine rotor blades

DOEpatents

Livingston, Jamie T.; Burke, Arthur H. E.; Bakhuis, Jan Willem; Van Breugel, Sjef; Billen, Andrew

2008-04-01

A method of manufacturing a root portion of a wind turbine blade includes, in an exemplary embodiment, providing an outer layer of reinforcing fibers including at least two woven mats of reinforcing fibers, providing an inner layer of reinforcing fibers including at least two woven mats of reinforcing fibers, and positioning at least two bands of reinforcing fibers between the inner and outer layers, with each band of reinforcing fibers including at least two woven mats of reinforcing fibers. The method further includes positioning a mat of randomly arranged reinforcing fibers between each pair of adjacent bands of reinforcing fibers, introducing a polymeric resin into the root potion of the wind turbine blade, infusing the resin through the outer layer, the inner layer, each band of reinforcing fibers, and each mat of random reinforcing fibers, and curing the resin to form the root portion of the wind turbine blade.

KSC-06pd0573

NASA Image and Video Library

2006-04-05

KENNEDY SPACE CENTER, FLA. - In Orbiter Processing Facility bay 2 at NASA's Kennedy Space Center, Endeavour waits for installation of its reinforced carbon-carbon nose cap. The nose cap is insulated with thermal protection system blankets made of a woven ceramic fabric. The special blankets help insulate the vehicle's nose cap and protect it from the extreme temperatures it will face during a mission. Photo credit: NASA/Jim Grossmann

KSC-06pd0578

NASA Image and Video Library

2006-04-06

KENNEDY SPACE CENTER, FLA. - In Orbiter Processing Facility bay 2 at NASA's Kennedy Space Center, the reinforced carbon-carbon nose cap has been installed on Endeavour. The nose cap has been insulated with thermal protection system blankets made of a woven ceramic fabric. The special blankets help insulate the vehicle's nose cap and protect it from the extreme temperatures it will face during a mission. Photo credit: NASA/Jim Grossmann

KSC-06pd0580

NASA Image and Video Library

2006-04-06

KENNEDY SPACE CENTER, FLA. - The reinforced carbon-carbon nose cap has been installed on Endeavour in Orbiter Processing Facility bay 2 at NASA's Kennedy Space Center. The nose cap has been insulated with thermal protection system blankets made of a woven ceramic fabric. The special blankets help insulate the vehicle's nose cap and protect it from the extreme temperatures it will face during a mission. Photo credit: NASA/Jim Grossmann

Stochastic Nonlinear Response of Woven CMCs

NASA Technical Reports Server (NTRS)

Kuang, C. Liu; Arnold, Steven M.

2013-01-01

It is well known that failure of a material is a locally driven event. In the case of ceramic matrix composites (CMCs), significant variations in the microstructure of the composite exist and their significance on both deformation and life response need to be assessed. Examples of these variations include changes in the fiber tow shape, tow shifting/nesting and voids within and between tows. In the present work, the influence of scale specific architectural features of woven ceramic composite are examined stochastically at both the macroscale (woven repeating unit cell (RUC)) and structural scale (idealized using multiple RUCs). The recently developed MultiScale Generalized Method of Cells methodology is used to determine the overall deformation response, proportional elastic limit (first matrix cracking), and failure under tensile loading conditions and associated probability distribution functions. Prior results showed that the most critical architectural parameter to account for is weave void shape and content with other parameters being less in severity. Current results show that statistically only the post-elastic limit region (secondary hardening modulus and ultimate tensile strength) is impacted by local uncertainties both at the macro and structural level.

Origin of tensile strength of a woven sample cut in bias directions

PubMed Central

Pan, Ning; Kovar, Radko; Dolatabadi, Mehdi Kamali; Wang, Ping; Zhang, Diantang; Sun, Ying; Chen, Li

2015-01-01

Textile fabrics are highly anisotropic, so that their mechanical properties including strengths are a function of direction. An extreme case is when a woven fabric sample is cut in such a way where the bias angle and hence the tension loading direction is around 45° relative to the principal directions. Then, once loaded, no yarn in the sample is held at both ends, so the yarns have to build up their internal tension entirely via yarn–yarn friction at the interlacing points. The overall fabric strength in such a sample is a result of contributions from the yarns being pulled out and those broken during the process, and thus becomes a function of the bias direction angle θ, sample width W and length L, along with other factors known to affect fabric strength tested in principal directions. Furthermore, in such a bias sample when the major parameters, e.g. the sample width W, change, not only the resultant strengths differ, but also the strength generating mechanisms (or failure types) vary. This is an interesting problem and is analysed in this study. More specifically, the issues examined in this paper include the exact mechanisms and details of how each interlacing point imparts the frictional constraint for a yarn to acquire tension to the level of its strength when both yarn ends were not actively held by the testing grips; the theoretical expression of the critical yarn length for a yarn to be able to break rather than be pulled out, as a function of the related factors; and the general relations between the tensile strength of such a bias sample and its structural properties. At the end, theoretical predictions are compared with our experimental data. PMID:26064655

Multi-Scale Analyses of Three Dimensional Woven Composite 3D Shell With a Cut Out Circle

NASA Astrophysics Data System (ADS)

Nguyen, Duc Hai; Wang, Hu

2018-06-01

A composite material are made by combining two or more constituent materials to obtain the desired material properties of each product type. The matrix material which can be polymer and fiber is used as reinforcing material. Currently, the polymer matrix is widely used in many different fields with differently designed structures such as automotive structures and aviation, aerospace, marine, etc. because of their excellent mechanical properties; in addition, they possess the high level of hardness and durability together with a significant reduction in weight compared to traditional materials. However, during design process of structure, there will be many interruptions created for the purpose of assembling the structures together or for many other design purposes. Therefore, when this structure is subject to load-bearing, its failure occurs at these interruptions due to stress concentration. This paper proposes multi-scale modeling and optimization strategies in evaluation of the effectiveness of fiber orientation in an E-glass/Epoxy woven composite 3D shell with circular holes at the center investigated by FEA results. A multi-scale model approach was developed to predict the mechanical behavior of woven composite 3D shell with circular holes at the center with different designs of material and structural parameters. Based on the analysis result of laminae, we have found that the 3D shell with fiber direction of 450 shows the best stress and strain bearing capacity. Thus combining several layers of 450 fiber direction in a multi-layer composite 3D shell reduces the stresses concentrated on the cuts of the structures.

Fabrication of Glass Fiber Reinforced Composites Based on Bio-Oil Phenol Formaldehyde Resin

PubMed Central

Cui, Yong; Chang, Jianmin; Wang, Wenliang

2016-01-01

In this study, bio-oil from fast pyrolysis of renewable biomass was added by the mass of phenol to synthesize bio-oil phenol formaldehyde (BPF) resins, which were used to fabricate glass fiber (GF) reinforced BPF resin (GF/BPF) composites. The properties of the BPF resin and the GF/BPF composites prepared were tested. The functional groups and thermal property of BPF resin were thoroughly investigated by Fourier transform infrared (FTIR) spectra and dynamic thermomechanical analysis (DMA). Results indicated that the addition of 20% bio-oil exhibited favorable adaptability for enhancing the stiffness and heat resistance of phenol formaldehyde (PF) resin. Besides, high-performance GF/BPF composites could be successfully prepared with the BPF resin based on hand lay-up process. The interface characteristics of GF/BPF composites were determined by the analysis of dynamic wettability (DW) and scanning electron microscopy (SEM). It exhibited that GF could be well wetted and embedded in the BPF resin with the bio-oil addition of 20%. PMID:28774009

Advanced Ceramic Matrix Composites with Multifunctional and Hybrid Structures

NASA Technical Reports Server (NTRS)

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 (< 1 mm) 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.

Effects of vertically aligned carbon nanotubes on shear performance of laminated nanocomposite bonded joints.

PubMed

Askari, Davood; Ghasemi-Nejhad, Mehrdad N

2012-08-01

The main objective is to improve the most commonly addressed weakness of the laminated composites (i.e. delamination due to poor interlaminar strength) using carbon nanotubes (CNTs) as reinforcement between the laminae and in the transverse direction. In this work, a chemical vapor deposition technique has been used to grow dense vertically aligned arrays of CNTs over the surface of chemically treated two-dimensionally woven cloth and fiber tows. The nanoforest-like fabrics can be used to fabricate three-dimensionally reinforced laminated nanocomposites. The presence of CNTs aligned normal to the layers and in-between the layers of laminated composites is expected to considerably enhance the properties of the laminates. To demonstrate the effectiveness of our approach, composite single lap-joint specimens were fabricated for interlaminar shear strength testing. It was observed that the single lap-joints with through-the-thickness CNT reinforcement can carry considerably higher shear stresses and strains. Close examination of the test specimens showed that the failure of samples with CNT nanoforests was completely cohesive, while the samples without CNT reinforcement failed adhesively. This concludes that the adhesion of adjacent carbon fabric layers can be considerably improved owing to the presence of vertically aligned arrays of CNT nanoforests.

Effects of vertically aligned carbon nanotubes on shear performance of laminated nanocomposite bonded joints

PubMed Central

Askari, Davood; Ghasemi-Nejhad, Mehrdad N

2012-01-01

The main objective is to improve the most commonly addressed weakness of the laminated composites (i.e. delamination due to poor interlaminar strength) using carbon nanotubes (CNTs) as reinforcement between the laminae and in the transverse direction. In this work, a chemical vapor deposition technique has been used to grow dense vertically aligned arrays of CNTs over the surface of chemically treated two-dimensionally woven cloth and fiber tows. The nanoforest-like fabrics can be used to fabricate three-dimensionally reinforced laminated nanocomposites. The presence of CNTs aligned normal to the layers and in-between the layers of laminated composites is expected to considerably enhance the properties of the laminates. To demonstrate the effectiveness of our approach, composite single lap-joint specimens were fabricated for interlaminar shear strength testing. It was observed that the single lap-joints with through-the-thickness CNT reinforcement can carry considerably higher shear stresses and strains. Close examination of the test specimens showed that the failure of samples with CNT nanoforests was completely cohesive, while the samples without CNT reinforcement failed adhesively. This concludes that the adhesion of adjacent carbon fabric layers can be considerably improved owing to the presence of vertically aligned arrays of CNT nanoforests. PMID:27877502

Cytotoxicity of silica-glass fiber reinforced composites.

PubMed

Meriç, Gökçe; Dahl, Jon E; Ruyter, I Eystein

2008-09-01

Silica-glass fiber reinforced polymers can be used for many kinds of dental applications. The fiber reinforcement enhances the mechanical properties of the polymers, and they have good esthetic attributes. There is good initial bonding of glass fibers to polymers via an interface made from silane coupling agents. The aim of this in vitro study was to determine the cytotoxicity of two polymers reinforced with two differently sized silica-glass fibers before and after thermal cycling. Cytotoxicity of the polymers without fibers was also evaluated. Two different resin mixtures (A and B) were prepared from poly(vinyl chloridecovinylacetate) powder and poly(methyl methacrylate) (PMMA) dissolved in methyl methacrylate and mixed with different cross-linking agents. The resin A contained the cross-linking agents ethylene glycol dimethacrylate and 1,4-butanediol dimethacrylate, and for resin B diethylene glycol dimethacrylate was used. Woven silica-glass fibers were used for reinforcement. The fibers were sized with either linear poly(butyl methacrylate)-sizing or cross-linking PMMA-sizing. Cytotoxicity was evaluated by filter diffusion test (ISO 7405:1997) of newly made and thermocycled test specimens. Extracts were prepared according to ISO 10993-12 from newly made and from thermocycled specimens and tested by the MTT assay. The results from the experiments were statistically analyzed by one-way ANOVA and Tukey's test (rho<0.05). The filter diffusion test disclosed no change in staining intensity at the cell-test sample contact area indicating non-cytotoxicity in all experimental groups. Cell viability assessed by MTT assay was more than 90% in all experimental groups. All are non-cytotoxic. It can be concluded that correctly processed heat polymerized silica-glass fiber reinforced polymers induced no cytotoxicity and that thermocycling did not alter this property.

Abrasion of Candidate Spacesuit Fabrics by Simulated Lunar Dust

NASA Technical Reports Server (NTRS)

Gaier, James R.; Meador, Mary Ann; Rogers, Kerry J.; Sheehy, Brennan H.

2009-01-01

A protocol has been developed that produced the type of lunar soil abrasion damage observed on Apollo spacesuits. This protocol was then applied to four materials (Kevlar (DuPont), Vectran (Kuraray Co., Ltd.), Orthofabric, and Tyvek (DuPont)) that are candidates for advanced spacesuits. Three of the four new candidate fabrics (all but Vectran) were effective at keeping the dust from penetrating to layers beneath. In the cases of Kevlar and Orthofabric this was accomplished by the addition of a silicone layer. In the case of Tyvek, the paper structure was dense enough to block dust transport. The least abrasive damage was suffered by the Tyvek. This was thought to be due in large part to its non-woven paper structure. The woven structures were all abraded where the top of the weave was struck by the abrasive. Of these, the Orthofabric suffered the least wear, with both Vectran and Kevlar suffering considerably more extensive filament breakage.

Nacre-mimetic bulk lamellar composites reinforced with high aspect ratio glass flakes.

PubMed

Guner, Selen N Gurbuz; Dericioglu, Arcan F

2016-12-05

Nacre-mimetic epoxy matrix composites reinforced with readily available micron-sized high aspect ratio C-glass flakes were fabricated by a relatively simple, single-step, scalable, time, cost and man-power effective processing strategy: hot-press assisted slip casting (HASC). HASC enables the fabrication of preferentially oriented two-dimensional inorganic reinforcement-polymer matrix bulk lamellar composites with a micro-scale structure resembling the brick-and-mortar architecture of nacre. By applying the micro-scale design guideline found in nacre and optimizing the relative volume fractions of the reinforcement and the matrix as well as by anchoring the brick-and-mortar architecture, and tailoring the interface between reinforcements and the matrix via silane coupling agents, strong, stiff and tough bio-inspired nacre-mimetic bulk composites were fabricated. As a result of high shear stress transfer lengths and effective stress transfer at the interface achieved through surface functionalization of the reinforcements, fabricated bulk composites exhibited enhanced mechanical performance as compared to neat epoxy. Furthermore, governed flake pull-out mode along with a highly torturous crack path, which resulted from extensive deflection and meandering of the advancing crack around well-aligned high aspect ratio C-glass flakes, have led to high work-of-fracture values similar to nacre.

Graphene-Reinforced Metal and Polymer Matrix Composites

NASA Astrophysics Data System (ADS)

Kasar, Ashish K.; Xiong, Guoping; Menezes, Pradeep L.

2018-03-01

Composites have tremendous applicability due to their excellent capabilities. The performance of composites mainly depends on the reinforcing material applied. Graphene is successful as an efficient reinforcing material due to its versatile as well as superior properties. Even at very low content, graphene can dramatically improve the properties of polymer and metal matrix composites. This article reviews the fabrication followed by mechanical and tribological properties of metal and polymer matrix composites filled with different kinds of graphene, including single-layer, multilayer, and functionalized graphene. Results reported to date in literature indicate that functionalized graphene or graphene oxide-polymer composites are promising materials offering significantly improved strength and frictional properties. A similar trend of improved properties has been observed in case of graphene-metal matrix composites. However, achieving higher graphene loading with uniform dispersion in metal matrix composites remains a challenge. Although graphene-reinforced composites face some challenges, such as understanding the graphene-matrix interaction or fabrication techniques, graphene-reinforced polymer and metal matrix composites have great potential for application in various fields due to their outstanding properties.

Graphene-Reinforced Metal and Polymer Matrix Composites

NASA Astrophysics Data System (ADS)

Kasar, Ashish K.; Xiong, Guoping; Menezes, Pradeep L.

2018-06-01

Composites have tremendous applicability due to their excellent capabilities. The performance of composites mainly depends on the reinforcing material applied. Graphene is successful as an efficient reinforcing material due to its versatile as well as superior properties. Even at very low content, graphene can dramatically improve the properties of polymer and metal matrix composites. This article reviews the fabrication followed by mechanical and tribological properties of metal and polymer matrix composites filled with different kinds of graphene, including single-layer, multilayer, and functionalized graphene. Results reported to date in literature indicate that functionalized graphene or graphene oxide-polymer composites are promising materials offering significantly improved strength and frictional properties. A similar trend of improved properties has been observed in case of graphene-metal matrix composites. However, achieving higher graphene loading with uniform dispersion in metal matrix composites remains a challenge. Although graphene-reinforced composites face some challenges, such as understanding the graphene-matrix interaction or fabrication techniques, graphene-reinforced polymer and metal matrix composites have great potential for application in various fields due to their outstanding properties.

Nanofibrous Smart Fabrics from Twisted Yarns of Electrospun Piezopolymer.

PubMed

Yang, Enlong; Xu, Zhe; Chur, Lucas K; Behroozfar, Ali; Baniasadi, Mahmoud; Moreno, Salvador; Huang, Jiacheng; Gilligan, Jules; Minary-Jolandan, Majid

2017-07-19

Smart textiles are envisioned to make a paradigm shift in wearable technologies to directly impart functionality into the fibers rather than integrating sensors and electronics onto conformal substrates or skin in wearable devices. Among smart materials, piezoelectric fabrics have not been widely reported, yet. Piezoelectric smart fabrics can be used for mechanical energy harvesting, for thermal energy harvesting through the pyroelectric effect, for ferroelectric applications, as pressure and force sensors, for motion detection, and for ultrasonic sensing. We report on mechanical and material properties of the plied nanofibrous piezoelectric yarns as a function of postprocessing conditions including thermal annealing and drawing (stretching). In addition, we used a continuous electrospinning setup to directly produce P(VDF-TrFE) nanofibers and convert them into twisted plied yarns, and demonstrated application of these plied yarns in woven piezoelectric fabrics. The results of this work can be an early step toward realization of piezoelectric smart fabrics.

Development of a Meso-Scale Material Model for Ballistic Fabric and Its Use in Flexible-Armor Protection Systems

NASA Astrophysics Data System (ADS)

Grujicic, M.; Bell, W. C.; Arakere, G.; He, T.; Xie, X.; Cheeseman, B. A.

2010-02-01

A meso-scale ballistic material model for a prototypical plain-woven single-ply flexible armor is developed and implemented in a material user subroutine for the use in commercial explicit finite element programs. The main intent of the model is to attain computational efficiency when calculating the mechanical response of the multi-ply fabric-based flexible-armor material during its impact with various projectiles without significantly sacrificing the key physical aspects of the fabric microstructure, architecture, and behavior. To validate the new model, a comparative finite element method analysis is carried out in which: (a) the plain-woven single-ply fabric is modeled using conventional shell elements and weaving is done in an explicit manner by snaking the yarns through the fabric and (b) the fabric is treated as a planar continuum surface composed of conventional shell elements to which the new meso-scale unit-cell based material model is assigned. The results obtained show that the material model provides a reasonably good description for the fabric deformation and fracture behavior under different combinations of fixed and free boundary conditions. Finally, the model is used in an investigation of the ability of a multi-ply soft-body armor vest to protect the wearer from impact by a 9-mm round nose projectile. The effects of inter-ply friction, projectile/yarn friction, and the far-field boundary conditions are revealed and the results explained using simple wave mechanics principles, high-deformation rate material behavior, and the role of various energy-absorbing mechanisms in the fabric-based armor systems.

Mechanical Behavior of Fabric-Film Laminates

NASA Technical Reports Server (NTRS)

Said, Magdi S.

1999-01-01

Inflatable structures are gaining wide support in planetary scientific missions as well as commercial applications. For such applications a new class of materials made of laminating thin homogenous films to lightweight fabrics are being considered us structura1 gas envelops. The emerging composite materials are a result of recent advances in the manufacturing cf 1ightweight, high strength fibers, fabrics and scrims. The lamination of these load-carrying members with the proper gas barrier film results in wide range of materials suitable for various loading and environmental conditions. Polyester - based woven fabrics laminated to thin homogeneus film of polyester (Maylar) is an example of this class. This fabric/ film laminate is being considered for the development a material suitable for building large gas envelopes for use in the NASA Ultra Long Duration Balloon Program (ULDB). Compared to commercial homogeneus films, the material provides relatively high strength to weight ratio as well as better resistance to crack and tear propagation. The purpose of this papers is to introduce the mechanical behavior of this class of multi-layers composite and to highlight some of the concerns observed during the characterization of these laminate composites.

Application of boron/epoxy reinforced aluminum stringers and boron/epoxy skid gear for the CH54B helicopter tail cone. Phase 2: Fabrication, inspection and flight test

NASA Technical Reports Server (NTRS)

Welge, R. T.

1972-01-01

A CH-54B Skycrane helicopter was fabricated with boron/epoxy reinforced stringers in the tail cone and boron/epoxy tubes in the tail skid. The fabrication of the tail cone was made with conventional tooling, production shop personnel, and no major problems. The flight test program includes a stress and vibration survey using strain gages and vibration transducers located in critical areas. The program to inspect and monitor the reliability of the components is discussed.

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

NASA Astrophysics Data System (ADS)

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

2016-04-01

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

Atmospheric pressure plasma deposition of antimicrobial coatings on non-woven textiles

NASA Astrophysics Data System (ADS)

Nikiforov, Anton Yu.; Deng, Xiaolong; Onyshchenko, Iuliia; Vujosevic, Danijela; Vuksanovic, Vineta; Cvelbar, Uros; De Geyter, Nathalie; Morent, Rino; Leys, Christophe

2016-08-01

A simple method for preparation of nanoparticle incorporated non-woven fabric with high antibacterial efficiency has been proposed based on atmospheric pressure plasma process. In this work direct current plasma jet stabilized by fast nitrogen flow was used as a plasma deposition source. Three different types of the nanoparticles (silver, copper and zinc oxide nanoparticles) were employed as antimicrobial agents. X-ray photoelectron spectroscopy (XPS) measurements have shown a positive chemical shift observed for Ag 3d 5/2 (at 368.1 eV) suggests that silver nanoparticles (AgNPs) are partly oxidized during the deposition. The surface chemistry and the antibacterial activity of the samples against Staphylococcus aureus and Escherichia coli were investigated and analyzed. It is shown that the samples loaded with nanoparticles of Ag and Cu and having the barrier layer of 10 nm characterized by almost 97% of bacterial reduction whereas the samples with ZnO nanoparticles provide 86% reduction of Staphylococcus aureus. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

Simulation of Degraded Properties of 2D plain Woven C/SiC Composites under Preloading Oxidation Atmosphere

NASA Astrophysics Data System (ADS)

Chen, Xihui; Sun, Zhigang; Sun, Jianfen; Song, Yingdong

2017-12-01

In this paper, a numerical model which incorporates the oxidation damage model and the finite element model of 2D plain woven composites is presented for simulation of the oxidation behaviors of 2D plain woven C/SiC composite under preloading oxidation atmosphere. The equal proportional reduction method is firstly proposed to calculate the residual moduli and strength of unidirectional C/SiC composite. The multi-scale method is developed to simulate the residual elastic moduli and strength of 2D plain woven C/SiC composite. The multi-scale method is able to accurately predict the residual elastic modulus and strength of the composite. Besides, the simulated residual elastic moduli and strength of 2D plain woven C/SiC composites under preloading oxidation atmosphere show good agreements with experimental results. Furthermore, the preload, oxidation time, temperature and fiber volume fractions of the composite are investigated to show their influences upon the residual elastic modulus and strength of 2D plain woven C/SiC composites.

Effect of fabrication processes on mechanical properties of glass fiber reinforced polymer composites for 49 meter (160 foot) recreational yachts

NASA Astrophysics Data System (ADS)

Kim, Dave (dea-wook); Hennigan, Daniel John; Beavers, Kevin Daniel

2010-03-01

Polymer composite materialsoffer high strength and stiffness to weight ratio, corrosion resistance, and total life cost reductions that appeal to the marine industry. The advantages of composite construction have led to their incorporation in U.S. yacht hull structures over 46 meters (150 feet) in length. In order to construct even larger hull structures, higher quality composites with a lower cost production techniques need to be developed. In this study, the effect of composite hull fabrication processes on mechanical properties of glass fiber reinforced plastic(GFRP) composites is presented. Fabrication techniques used in this study are hand lay-up (HL), vacuum infusion (VI), and hybrid (HL+VI) processes. Mechanical property testing includes: tensile, compressive, and ignition loss sample analysis. Results demonstrate that the vacuum pressure implemented during composite fabrication has an effect on mechanical properties. The VI processed GFRP yields improved mechanical properties in tension/compression strengths and tensile modulus. The hybrid GFRP composites, however, failed in a sequential manor, due to dissimilar failure modes in the HL and VI processed sides. Fractography analysis was conducted to validate the mechanical property testing results

Effect of natural weathering conditions on the dynamic behavior of woven aramid composites

NASA Astrophysics Data System (ADS)

Kaya, A. I.; Kısa, M.; Özen, M.

2018-02-01

In this study, aging of woven aramid/epoxy composites under different natural conditions were studied. Composite beams were manufactured by Vacuum Assisted Resin Infusion Method (VARIM). Composites were cut into specimen according to ASTM D3039 and vibration tests. Elastic moduli of reference composites were found according to ASTM D3039 standard. Validation of methodology was performed numerically in Ansys software before aging process. An algorithm, which is predicated on FFT (Fast Fourier Transforms), was composed in Matlab to process output of vibration analysis data so as to identify natural frequencies of beams. Composites were aged for 12 months and various natural weathering aging conditions effects on woven aramid composite beams were surveyed through vibration analysis with 3 months interval. Five specimens of woven aramid beams were considered for dynamic tests and effect of aging on first three natural frequencies were determined.

Design and fabrication of novel anode flow-field for commercial size solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Canavar, Murat; Timurkutluk, Bora

2017-04-01

In this study, nickel based woven meshes are tested as not only anode current collecting meshes but also anode flow fields instead of the conventional gas channels fabricated by machining. For this purpose, short stacks with different anode flow fields are designed and built by using different number of meshes with various wire diameters and widths of opening. A short stack with classical machined flow channels is also constructed. Performance and impedance measurements of the short stacks with commercial size cells of 81 cm2 active area are performed and compared. The results reveal that it is possible to create solid oxide fuel cell anode flow fields with woven meshes and obtain acceptable power with a proper selection of the mesh number, type and orientation.

Fabrication of ceramic substrate-reinforced and free forms

NASA Technical Reports Server (NTRS)

Quentmeyer, R. J.; Mcdonald, G.; Hendricks, R. C.

1985-01-01

Components fabricated of, or coated with, ceramics have lower parasitic cooling requirements. Techniques are discussed for fabricating thin-shell ceramic components and ceramic coatings for applications in rocket or jet engine environments. Thin ceramic shells with complex geometric forms involving convolutions and reentrant surfaces were fabricated by mandrel removal. Mandrel removal was combined with electroplating or plasma spraying and isostatic pressing to form a metal support for the ceramic. Rocket engine thrust chambers coated with 0.08 mm (3 mil) of ZrO2-8Y2O3 had no failures and a tenfold increase in engine life. Some measured mechanical properties of the plasma-sprayed ceramic are presented.

Recycling of woven carbon-fibre-reinforced polymer composites using supercritical water.

PubMed

Knight, Chase C; Zeng, Changchun; Zhang, Chuck; Wang, Ben

2012-01-01

Over the past few years, there has been great deal of interest in recycling carbon-fibre-reinforced polymer composites. One method that has shown promising results involves the use of supercritical fluids to achieve separation between matrix and fibres by effectively degrading the resin into lower molecular weight compounds. In addition, the solvents used are environmentally benign and can also be recovered and reused. In this study, supercritical water with 0.05 M KOH as the catalyst was used for the recycling of an aerospace-grade high-performance epoxy carbon fibre composite (Hexcel 8552/IM7). The morphology of the reclaimed fibres was observed by scanning electron microscopy, and the tensile properties of the fibres were measured by single filament testing. The effects of processing time on the resin elimination efficiency and fibre property retention were investigated. With the process developed in this research, as much as 99.2 wt% resin elimination was achieved, resulting in the recovery of clean, undamaged fibres. The reclaimed fibres retained the original tensile strength. The feasibility of recycling multiple layer composites was also explored.

KSC-06pd0579

NASA Image and Video Library

2006-04-06

KENNEDY SPACE CENTER, FLA. - In Orbiter Processing Facility bay 2 at NASA's Kennedy Space Center, a worker checks the reinforced carbon-carbon nose cap after installation on Endeavour. The nose cap has been insulated with thermal protection system blankets made of a woven ceramic fabric. The special blankets help insulate the vehicle's nose cap and protect it from the extreme temperatures it will face during a mission. Photo credit: NASA/Jim Grossmann

Finger materials for air cushion vehicles. Volume 1: Flexible coatings for finger materials

NASA Astrophysics Data System (ADS)

Conn, P. K.; Snell, I. C.; Klemens, W.

1984-12-01

Twenty polymer formulations from ten selected gum rubber polymers or polymer blends and fourteen formulations of castable liquid polyurethane polymers were characterized as coatings for the coated fabric that is the type material used to make flexible fingers for air cushion vehicles. The formulations were screened for crack growth and flexural fatigue resistance; the results were compared to results from a natural rubber/cisabutadiene blend control coating. In addition, selected polymers were evaluated with primary and secondary characterization tests and the results compared to results from the control formulation. One polymer also was used to evaluate the use of a reticulated carbon black to improve thermal conductivity. Several polymers had better crack growth resistance and a number had better flexural fatique resistance than the control polymer. A clorinated polyethylene polymer coated on nylon fabric had properties equivalent to the control polymer coated on nylon fabric. Hysteresis tests at different rates of deformation yielded results which suggested that the standard tests may not identify polymers with improved performance on air cushion vehicles. Woven fabric, knit, and mat structures were evaluated as reinforcements for polymer coatings; the knit and mat structures were not as efficient on a strength-to-weight basis as woven fabrics.

Woven TPS Mechanical Property Evaluation

NASA Technical Reports Server (NTRS)

Gonzales, Gregory Lewis; Kao, David Jan-Woei; Stackpoole, Margaret M.

2013-01-01

Woven Thermal Protection Systems (WTPS) is a relatively new program funded by the Office of the Chief Technologist (OCT). The WTPS approach to producing TPS architectures uses precisely engineered 3-D weaving techniques that allow tailoring material characteristics needed to meet specific mission requirements. A series of mechanical tests were performed to evaluate performance of different weave types, and get a better understanding of failure modes expected in these three-dimensional architectures. These properties will aid in material down selection and guide selection of the appropriate WTPS for a potential mission.

Impact behaviour of auxetic Kevlar®/ epoxy composites

NASA Astrophysics Data System (ADS)

Yang, S.; Chalivendra, V. B.; Kim, Y. K.

2017-10-01

Experimental study was performed to investigate fracture and impact properties of novel Auxetic Kevlar® laminated composites. For comparison, standard Kevlar® woven composites with and without polyurethane surface treatment were also considered in this study. For these three composites, short nylon fibers of two different fiber lengths and three different fiber densities were flocked between laminates. Vacuum infusion process along with optimized compaction was employed to fabricate composites. The double cantilever beam configuration was used to investigate the fracture properties. The Auxetic Kevlar® composites showed a significant improvement of 225% in fracture toughness compared to regular woven Kevlar® composites. Furthermore, the initiation toughness was increased by 577% with the application of flocking in Auxetic Kevlar®. During impact testing, the Auxetic Kevlar® reinforced composites showed a significant reduction in damaged area compared to woven counterpart. On the other hand, the reduction in damaged area influenced the reduction in impact energy absorption.

Fiber and fabric solar cells by directly weaving carbon nanotube yarns with CdSe nanowire-based electrodes

NASA Astrophysics Data System (ADS)

Zhang, Luhui; Shi, Enzheng; Ji, Chunyan; Li, Zhen; Li, Peixu; Shang, Yuanyuan; Li, Yibin; Wei, Jinquan; Wang, Kunlin; Zhu, Hongwei; Wu, Dehai; Cao, Anyuan

2012-07-01

Electrode materials are key components for fiber solar cells, and when combined with active layers (for light absorption and charge generation) in appropriate ways, they enable design and fabrication of efficient and innovative device structures. Here, we apply carbon nanotube yarns as counter electrodes in combination with CdSe nanowire-grafted primary electrodes (Ti wire) for making fiber and fabric-shaped photoelectrochemical cells with power conversion efficiencies in the range 1% to 2.9%. The spun-twist long nanotube yarns possess both good electrical conductivity and mechanical flexibility compared to conventional metal wires or carbon fibers, which facilitate fabrication of solar cells with versatile configurations. A unique feature of our process is that instead of making individual fiber cells, we directly weave single or multiple nanotube yarns with primary electrodes into a functional fabric. Our results demonstrate promising applications of semiconducting nanowires and carbon nanotubes in woven photovoltaics.Electrode materials are key components for fiber solar cells, and when combined with active layers (for light absorption and charge generation) in appropriate ways, they enable design and fabrication of efficient and innovative device structures. Here, we apply carbon nanotube yarns as counter electrodes in combination with CdSe nanowire-grafted primary electrodes (Ti wire) for making fiber and fabric-shaped photoelectrochemical cells with power conversion efficiencies in the range 1% to 2.9%. The spun-twist long nanotube yarns possess both good electrical conductivity and mechanical flexibility compared to conventional metal wires or carbon fibers, which facilitate fabrication of solar cells with versatile configurations. A unique feature of our process is that instead of making individual fiber cells, we directly weave single or multiple nanotube yarns with primary electrodes into a functional fabric. Our results demonstrate promising applications

A two-step sealing-and-reinforcement SU8 bonding paradigm for the fabrication of shallow microchannels

NASA Astrophysics Data System (ADS)

Mehboudi, Aryan; Yeom, Junghoon

2018-03-01

Adhesive bonding is a key technique to create microfluidic devices when two separate substrates are used to form microchannels. Among many adhesives explored in microchannel fabrication, SU8 has been widely used as an adhesive layer for sealing the microchannel sidewalls. The majority of the available SU8-based bonding methods, however, suffer from the difficulties associated with sealing of two important types of the microchannel architecture: (1) shallow microchannels with small patterns on a large area, and (2) microchannels with ultra-low aspect ratios (e.g. 6 mm in width and 2~μ m in height). In this paper, a new bonding paradigm based upon the low-temperature and low-pressure SU8 bonding, consisting of two steps of sealing using a thin-SU8-coated PET film and bonding reinforcement using a SU8-coated glass slide, is proposed to resolve the aforementioned difficulties. Since it does not need complicated instruments such as a wafer bonding machine and a lamination device, the developed bonding paradigm is convenient and economical. We successfully demonstrate the compatibility of the proposed bonding paradigm with the two microchannel fabrication approaches based on the glass wet etching and the SU8 photo-lithography, where small microchannels with the innermost surfaces fully made of SU8 are obtained. A theoretical model is employed to better investigate the flow characteristics and the structural behavior of the microchannel including the PET film deformation, strain and von Mises stress distributions, bonding strength, etc. Moreover, we demonstrate the fabrication of the multi-height deep-shallow microchannel sidewalls and their sealing using the SU8-coated PET film. Finally, as a proof-of-concept device, a microfluidic filter consisting of the double-height deep-shallow microchannel is fabricated for separation of 3 µm and 10 µm particles.

Micromechanics of fatigue in woven and stitched composites

NASA Technical Reports Server (NTRS)

Cox, B. N.; Dadkhah, M. S.; Inman, R. V.; Mitchell, M. R.; Morris, W. L.; Schroeder, S.

1991-01-01

The goal is to determine how microstructural factors, especially the architecture of microstructural factors, control fatigue damage in 3D reinforced polymer composites. Test materials were fabricated from various preforms, including stitched quasi-isotropic laminates, and through-the-thickness angle interlock, layer-to-layer angle interlock, and through-the-thickness stitching effect weaves. Preforms were impregnated with a tough resin by a special vacuum infiltration method. Most tests are being performed in uniaxial compression/compression loading. In all cases to date, failure has occurred not by delamination, but by shear failure, which occurs suddenly rather than by gradual macroscopic crack growth. Some theoretical aspects of bridging are also examined.

Turbine component, turbine blade, and turbine component fabrication process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delvaux, John McConnell; Cairo, Ronald Ralph; Parolini, Jason Robert

A turbine component, a turbine blade, and a turbine component fabrication process are disclosed. The turbine component includes ceramic matrix composite plies and a feature configured for preventing interlaminar tension of the ceramic matrix composite plies. The feature is selected from the group consisting of ceramic matrix composite tows or precast insert tows extending through at least a portion of the ceramic matrix composite plies, a woven fabric having fiber tows or a precast insert preventing contact between a first set of the ceramic matrix composite plies and a second set of the ceramic matrix composite plies, and combinations thereof.more » The process includes laying up ceramic matrix composite plies in a preselected arrangement and securing a feature configured for interlaminar tension.« less

Study on properties of CFRP fabricated by VA-RTM process

NASA Astrophysics Data System (ADS)

Jeoung, Sun Kyoung; Hwang, Ye Jin; Lee, Hyun Wook; Son, Soon Keun; Kim, Hyung Sik; Ha, Jin Uk

2016-03-01

Carbon fiber reinforced plastics (CFRP) have a lot of attention from industry and academia due to its excellent mechanical property. It has been used for aircraft, automotive and so on, since it can replace metallic materials and reduce total weight with increased physical properties. However, the manufacturing process and the material cost are still challenging to be commercialized in the automotive market. Therefore, many researchers are trying to minimize materials and process cost for broadening their applications. In this study, thermoset epoxy resins were used for binder of CFRP. Epoxy resins were investigated in order to figure out optimized curing speed under vacuum assisted resin transfer molding (VARTM) processing condition. Mechanical properties of CFRP with different carbon fiber orientation and woven carbon fiber were compared to mathematically simulated results. In order to develop the application of automobile component, reliability tests of CFRP were carried out. Tensile strength of CFRP is increased when the orientation angle between fiber and axis of load was decreased (90°→ 0°). It is considered that epoxy and carbon fiber absorbed the tensile energy because the orientation of fiber and the load bearing are matched with axis direction. In addition, the CFRP automobile engine hood was fabricated by VARTM process. Drop weight impact tests (20kg & 100kg weight) were carried out in order to simulate crash performance of CFRP engine hoods.

A wearable fabric-based speech-generating device: system design and case demonstration.

PubMed

Fleury, Amanda; Wu, Gloria; Chau, Tom

2018-05-26

Existing speech generating devices (SGD) often require caregiver intervention for setup and positioning, and thus limit opportunities for spontaneous social interaction. The advent of conductive fabrics presents an opportunity to render SGDs wearable, thus persistently available. Our goal was to design and test a wearable SGD incorporating resistive textile-based switches for a nonverbal pediatric participant with vision impairment. Quad-key fabric keypads were designed using two conductive fabrics in combination with felt and mesh insulators. The keypad with the most repeatable low force activations and the least cross-talk among keys was chosen for implementation in a wrist-worn, four-message textile SGD. The fabric-based SGD was used by a nonverbal pediatric participant for two one-week analysis periods, alternating with the user's current device for usage reference. Data were derived from usage logs, parent questionnaires and an end-of-study participant interview. The best performing keypad consisted of two layers of woven conductive fabrics and one layer of insulating felt with 10 mm apertures. Communicative interactions were higher with the fabric-based SGD, particularly at school. Unprompted initiation of communication was observed only with the fabric-based SGD. The persistent availability of the textile solution, along with esthetic appeal likely contributed to its utilization. While the participant preferred the fabric-based SGD, the parent opted for the iPod alternative, citing enhanced message intelligibility. Fabric-based SGDs are a new alternative to conventional SGD designs using rigid electronics. As such, tactile differentiability of keys, device wearability and esthetic personalization may be promising advantages for pediatric users. Implications for rehabilitation Fabric-based switches may be a promising alternative to conventional electro-mechanical switches for the control of speech-generating devices, offering functional (e.g., comfort and

An Evaluation of 3D Woven Orthogonal Composites' Potential in the Automotive Supply Chain

NASA Astrophysics Data System (ADS)

Taylor, Dalia

The automotive supply chain and its management can be a very complex process and comprises a long dynamic and complex network that consists of four primary segments: original equipment manufacturers (OEMs), first tier suppliers, sub tiers suppliers, and infrastructure suppliers. During the analysis of the current automotive industry it was identified that textile industry importance is considerable increasing as a part of the global automotive supply chain, because textile products are used for interior, exterior and even suspension parts and components. Automotive industry has an increasing demand for higher quality exterior panels with better functional properties and reduced weight. One of the main potentials for this demand is based on the three-dimensional woven composites technology innovations which can replace an existing technology. The new role of the textile industry could make important changes in the automotive supply chain industry, such as: changes in the size of the supply chain, the time to the market and the position of textile industry in the automotive supply chain structure. 3D composite materials from high performance fibers, such as glass and carbon, have been used for automotive applications in a limited way due to the low production rate and the lack of research and development. This research will contribute to the understanding of textile composites in transportation and the textile parameters that affect the performance characteristics of these materials. The research examines the performance characteristics of lighter and stronger 3D woven fabric composites made from fiberglass with the aim to improve fuel efficiency by reducing the total vehicle weight while maintaining safety standards. The performance characteristics of the 3D woven fabric composite can be designed by changing different construction parameters, such as picks density, pick roving linear density, arrangements of warp and z-yarns, and the number of warp and picks layers

75 FR 11557 - Woven Electric Blankets From China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-11

... From China AGENCY: United States International Trade Commission. ACTION: Scheduling of the final phase... States is materially retarded, by reason of less-than-fair-value imports from China of woven electric... blankets from the People's Republic of China are being sold in the United States at less than fair value...

Tensile Behavior of As-Fabricated and Burner-Rig Exposed SiC/SiC Composites with Hi-Nicalon Type-S Fibers

NASA Technical Reports Server (NTRS)

Yun, H. M.; Dicarlo, J. A.; Ogbuji, L. T.; Chen, Y. L.

2002-01-01

Tensile stress-strain curves were measured at room temperature and 1315 C for 2D-woven SiC/BN/SiC ceramic matrix composites (CMC) reinforced by two variations of Hi-Nicalon Type-S SiC fibers. These fibers, which contained a thin continuous carbon-rich layer on their as-produced surface, provided the as-fabricated CMC with good composite behavior and an ultimate strength and strain of -350 MPa and -0.5%, respectively. However, after un-stressed burner-rig exposure at 815 C for -100 hrs, CMC tensile specimens with cut edges and exposed interphases showed a significant decrease in ultimate properties with effectively no composite behavior. Microstructural observations show that the degradation was caused by internal fiber-fiber oxide bonding after removal of the carbon-rich fiber surface layer by the high-velocity combustion gases. On the other hand, SiC/BN/SiC CMC with Sylramic-iBN fibers without carbon-rich surfaces showed higher as-fabricated strength and no loss in strength after the same burner rig exposure. Based on the strong role of the carbon layer in these observations, a process method was developed and demonstrated for achieving better strength retention of Hi-Nicalon Type-S CMC during burner rig exposure. Other general approaches for minimizing this current deficiency with as-produced Type-S fibers are discussed.

Electron Microscopy Abrasion Analysis of Candidate Fabrics for Planetary Space Suit Protective Overgarment Application

NASA Technical Reports Server (NTRS)

Hennessy, Mary J.

1992-01-01

The Electron Microscopy Abrasion Analysis of Candidate Fabrics for Planetary Space Suit Protective Overgarment Application is in support of the Abrasion Resistance Materials Screening Test. The fundamental assumption made for the SEM abrasion analysis was that woven fabrics to be used as the outermost layer of the protective overgarment in the design of the future, planetary space suits perform best when new. It is the goal of this study to determine which of the candidate fabrics was abraded the least in the tumble test. The sample that was abraded the least will be identified at the end of the report as the primary candidate fabric for further investigation. In addition, this analysis will determine if the abrasion seen by the laboratory tumbled samples is representative of actual EVA Apollo abrasion.

76 FR 72161 - Laminated Woven Sacks From the People's Republic of China: Negative Preliminary Determination of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-22

... merchandise anti-circumvention inquiry to determine whether laminated woven sacks printed with two colors in... Circumvention (Printed Ink Colors) dated March 25, 2011. \\5\\ See Laminated Woven Sacks From the People's... to an exterior ply of paper that is suitable for high quality print graphics; \\6\\ printed with three...

Comparison of resin film infusion, resin transfer molding, and consolidation of textile preforms for primary aircraft structure

NASA Technical Reports Server (NTRS)

Suarez, J.; Dastin, S.

1992-01-01

Under NASA's Novel Composites for Wing and Fuselage Applications (NCWFA) Program, Grumman is developing innovative design concepts and cost-effective fabrication processes for damage-tolerant primary structures that can perform at a design ultimate strain level of 6000 micro-inch/inch. Attention has focused on the use of textile high-performance fiber-reinforcement concepts that provide improved damage tolerance and out-of-plane load capability, low-cost resin film infusion (RFI) and resin transfer molding (RTM) processes, and thermoplastic forming concepts. The fabrication of wing 'Y' spars by four different materials/processes methods is described: 'Y' spars fabricated using IM7 angle interlock 0/90 deg woven preforms with +/- 45 deg plies stitched with Toray high-strength graphite thread and processed using RFI and 3501-6 epoxy; 'Y' spars fabricated using G40-800 knitted/stitched preforms and processed using RFI and 3501-6 epoxy; 'Y' spars fabricated using G40-800 knitted/stitched preforms and processed using RTM and Tactix 123/H41 epoxy; and 'Y' spars fabricated using AS4(6k)/PEEK 150-g commingled angle interlock 0/90 deg woven preforms with +/- 45 deg commingled plies stitched using high-strength graphite thread and processed by consolidation. A comparison of the structural efficiency, processability, and projected acquisition cost of these representative spars is presented.

Remnant Woven Bone and Calcified Cartilage in Mouse Bone: Differences between Ages/Sex and Effects on Bone Strength

PubMed Central

Ip, Victoria; Toth, Zacharie; Chibnall, John; McBride-Gagyi, Sarah

2016-01-01

Introduction Mouse models are used frequently to study effects of bone diseases and genetic determinates of bone strength. Murine bones have an intracortical band of woven bone that is not present in human bones. This band is not obvious under brightfield imaging and not typically analyzed. Due to the band’s morphology and location it has been theorized to be remnant bone from early in life. Furthermore, lamellar and woven bone are well known to have differing mechanical strengths. The purpose of this study was to determine (i) if the band is from early life and (ii) if the woven bone or calcified cartilage contained within the band affect whole bone strength. Woven Bone Origin Studies In twelve to fourteen week old mice, doxycycline was used to label bone formed prior to 3 weeks old. Doxycycline labeling and woven bone patterns on contralateral femora matched well and encompassed an almost identical cross-sectional area. Also, we highlight for the first time in mice the presence of calcified cartilage exclusively within the band. However, calcified cartilage could not be identified on high resolution cone-beam microCT scans when examined visually or by thresholding methods. Mechanical Strength Studies Subsequently, three-point bending was used to analyze the effects of woven bone and calcified cartilage on whole bone mechanics in a cohort of male and female six and 13 week old Balb/C mice. Three-point bending outcomes were correlated with structural and compositional measures using multivariate linear regression. Woven bone composed a higher percent of young bones than older bones. However, calcified cartilage in older bones was twice that of younger bones, which was similar when normalized by area. Area and/or tissue mineral density accounted for >75% of variation for most strength outcomes. Percent calcified cartilage added significant predictive power to maximal force and bending stress. Calcified cartilage and woven bone could have more influence in genetic

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

NASA Astrophysics Data System (ADS)

Knight, Chase C.

of the polymer matrix. To date, very few studies have been reported in this area and the studies thus far have only focused on small scale feasibility and have only shown the recovery of random fibers. The goal of this research is to advance the knowledge in the field of sub-critical and supercritical fluid recycling by providing fundamental information that will be necessary to move this process forward to an industrial scale. This dissertation work consists of several phases of studies. In the first phase of this research, the feasibility of recycling woven CFRP was established on a scale approximately 30 times larger than previously reported. The industrial relevance was also conveyed, as the process was shown to remove up 99% of a highly cross-linked resin from an aerospace grade composite system with 100% retention of the single filament tensile strength and modulus whilst also retaining the highly valuable woven fiber structure. The second phase of research demonstrated the power of this technology to recycle multi-layer composites and provide the ability to reuse the highly valuable materials. Up to 99% resin elimination was achieved for a woven 12-layer aerospace grade composite. The recycled woven fabric layers, with excellent retention of the fiber architecture, were directly reused to fabricate reclaimed fiber composites (RFC). Manufacturing issues associated with the use of the recycled fiber were investigated. Several fabrication technologies were used to fabricate the composite, and the composites show moderate short beam shear strength and may be suitable for certain industrial applications. Moreover, fresh composites were also recycled, recovered, and reused to investigate the retention of flexural properties of the fibers after recycling. Up to 95% of the flexural strength and 98% of the flexural modulus was retained in the reclaimed fiber composites. The recycled resin residual can be incorporated into fresh resin and cured, demonstrating a near

Computational micromechanics of woven composites

NASA Technical Reports Server (NTRS)

Hopkins, Dale A.; Saigal, Sunil; Zeng, Xiaogang

1991-01-01

The bounds on the equivalent elastic material properties of a composite are presently addressed by a unified energy approach which is valid for both unidirectional and 2D and 3D woven composites. The unit cell considered is assumed to consist, first, of the actual composite arrangement of the fibers and matrix material, and then, of an equivalent pseudohomogeneous material. Equating the strain energies due to the two arrangements yields an estimate of the upper bound for the material equivalent properties; successive increases in the order of displacement field that is assumed in the composite arrangement will successively produce improved upper bound estimates.

KSC-06pd0575

NASA Image and Video Library

2006-04-05

KENNEDY SPACE CENTER, FLA. - In Orbiter Processing Facility bay 2 at NASA's Kennedy Space Center, workers are nearby as a crane lifts the reinforced carbon-carbon nose cap to be installed onto Endeavour. The nose cap is insulated with thermal protection system blankets made of a woven ceramic fabric. The special blankets help insulate the vehicle's nose cap and protect it from the extreme temperatures it will face during a mission. Photo credit: NASA/Jim Grossmann

KSC-06pd0577

NASA Image and Video Library

2006-04-05

KENNEDY SPACE CENTER, FLA. - In Orbiter Processing Facility bay 2 at NASA's Kennedy Space Center, a worker examines the underside of the reinforced carbon-carbon nose cap that will be installed on Endeavour. The nose cap is insulated with thermal protection system blankets made of a woven ceramic fabric. The special blankets help insulate the vehicle's nose cap and protect it from the extreme temperatures it will face during a mission. Photo credit: NASA/George Shelton

KSC-06pd0574

NASA Image and Video Library

2006-04-05

KENNEDY SPACE CENTER, FLA. - In Orbiter Processing Facility bay 2 at NASA's Kennedy Space Center, workers are preparing to move and install the reinforced carbon-carbon nose cap (on the stand) onto Endeavour. The nose cap is insulated with thermal protection system blankets made of a woven ceramic fabric. The special blankets help insulate the vehicle's nose cap and protect it from the extreme temperatures it will face during a mission. Photo credit: NASA/Jim Grossmann

KSC-06pd0257

NASA Image and Video Library

2006-02-09

KENNEDY SPACE CENTER, FLA. - The thermal protection system blanket insulation (foreground) has been hand-sewn onto a frame before being installed inside Endeavour's Reinforced Carbon-Carbon nose cap, seen in the background, in the NASA Kennedy Space Center Orbiter Processing Facility bay 2. Made of a woven ceramic fabric, the special blankets are used to help insulate the vehicle's nose cap and protect it from the extreme temperatures it will face during a mission. Photo credit: NASA/Jack Pfaller.

Development of Textile Reinforced Composites for Aircraft Structures

NASA Technical Reports Server (NTRS)

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.

Impact of Material and Architecture Model Parameters on the Failure of Woven Ceramic Matrix Composites (CMCs) via the Multiscale Generalized Method of Cells

NASA Technical Reports Server (NTRS)

Liu, Kuang C.; Arnold, Steven M.

2011-01-01

It is well known that failure of a material is a locally driven event. In the case of ceramic matrix composites (CMCs), significant variations in the microstructure of the composite exist and their significance on both deformation and life response need to be assessed. Examples of these variations include changes in the fiber tow shape, tow shifting/nesting and voids within and between tows. In the present work, the effects of many of these architectural parameters and material scatter of woven ceramic composite properties at the macroscale (woven RUC) will be studied to assess their sensitivity. The recently developed Multiscale Generalized Method of Cells methodology is used to determine the overall deformation response, proportional elastic limit (first matrix cracking), and failure under tensile loading conditions. The macroscale responses investigated illustrate the effect of architectural and material parameters on a single RUC representing a five harness satin weave fabric. Results shows that the most critical architectural parameter is weave void shape and content with other parameters being less in severity. Variation of the matrix material properties was also studied to illustrate the influence of the material variability on the overall features of the composite stress-strain response.

Evaluation of Mechanical Properties and Morphological Studies of Rice Husk (Treated/Untreated)-CaCO3 Reinforced Epoxy Hybrid Composites

NASA Astrophysics Data System (ADS)

Verma, Deepak; Joshi, Garvit; Gupta, Ayush

2016-10-01

Natural fiber reinforced composites are a very popular area of research because of the easy availability and biodegradability of these fibers. The manufacturing of natural fiber composite is done by reinforcing fibers in the particulate form, fiber form or in woven mat form. Natural fiber composites also utilize industrial wastes as a secondary reinforcements like fly ash, sludge etc. By keeping all these point of views in the present investigation the effect of rice husk flour (chemically treated/untreated) and micro sized calcium carbonate with epoxy resin have been evaluated. The diameter of rice husk flour was maintained at 600 µm through mechanical sieving machine. The husk flour was chemically treated with NaOH (5 % w/v). Mechanical properties like hardness, flexural impact and compression strength were evaluated and found to be superior in modified or chemically treated flour as compared to unmodified or untreated flour reinforced composites. Scanning electron microscopy (SEM) study was also undertaken for the developed composites. SEM study shows the distribution of the rice husk flour and calcium carbonate over the matrix.

Low Velocity Impact Behavior of Basalt Fiber-Reinforced Polymer Composites

NASA Astrophysics Data System (ADS)

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

2017-06-01

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

Manufacture and performance of carbon/epoxy 3-D woven composites

NASA Technical Reports Server (NTRS)

Brandt, J.; Drechsler, K.; Mohamed, Mansour; Gu, PU

1992-01-01

This paper evaluates 3-D orthogonal woven carbon/epoxy composites. Preforms were manufactured on an automatic 3-D weaving machine developed at N.C. State University. Matrix infiltration was conducted at MBB Central Laboratories. Testing was carried out at both locations and the joint results will be reported. The properties investigated include: interlaminar shear strength, compression, compression after impact, bending, tensile and penetration resistance. The 3-D orthogonal woven composites were compared with laminated and other 3-D composites made with preforms having interlock structure. C-scans were used to examine the quality of infiltration and the damage area after impact. The performance of the composites made from the 3-D orthogonal preforms showed superior properties compared to the other composites. The penetration resistance test showed unexpectedly very good performance.

The influence of FLiNaK salt impregnation on the mechanical properties of a 2D woven C/C composite

NASA Astrophysics Data System (ADS)

Zhang, Dongsheng; Xia, Huihao; Yang, Xinmei; Feng, Shanglei; Song, Jinliang; Zhou, Xingtai

2017-03-01

Impregnating of molten LiF-NaF-KF salt (LiF-NaF-KF: 46.5-11.5-42 mol%, FLiNaK) into a 2D woven C/C composite was performed at 650 °C under different pressure. The weight gain and mechanical properties change of the 2D woven C/C composite after FLiNaK salt impregnation were measured. The FLiNaK salt distribution into the 2D woven C/C composite was observed by X-ray computed tomography (X-ray CT) and scanning electron microscopy. The results showed that the weight gain of the 2D woven C/C composite increased with increasing impregnating pressure. In X-ray CT images, FLiNaK salt was distributed into the open pores and fissures among fiber bundles and neighboring plies. The interlaminar shear strength, compressive strength, and flexural strength of the 2D woven C/C composite increased with the increase of weight gain. The influence of FLiNaK salt impregnation on the mechanical properties was attributed to the coupling effect of re-densification of FLiNaK salt impregnation and residual stress formed in 2D woven C/C composite.

Experimental Analysis of the Influence of Drill Point Angle and Wear on the Drilling of Woven CFRPs

PubMed Central

Feito, Norberto; Díaz-Álvarez, José; Díaz-Álvarez, Antonio; Cantero, José Luis; Miguélez, María Henar

2014-01-01

This paper focuses on the effect of the drill geometry on the drilling of woven Carbon Fiber Reinforced Polymer composite (CFRPs). Although different geometrical effects can be considered in drilling CFRPs, the present work focuses on the influence of point angle and wear because they are the important factors influencing hole quality and machining forces. Surface quality was evaluated in terms of delamination and superficial defects. Three different point angles were tested representative of the geometries commonly used in the industry. Two wear modes were considered, being representative of the wear patterns commonly observed when drilling CFRPs: flank wear and honed cutting edge. It was found that the crossed influence of the point angle and wear were significant to the thrust force. Delamination at the hole entry and exit showed opposite trends with the change of geometry. Also, cutting parameters were checked showing the feed’s dominant influence on surface damage. PMID:28788675

Research notes : geotextile fabrics under asphalt concrete overlays.

DOT National Transportation Integrated Search

1992-12-01

Last year, the City of Portland decided to place geotextile fabrics under asphalt concrete overlays for pavement reinforcement and crack retardation. The City expected the following benefits from using the fabrics: retardation of reflective cracks, r...

Time-to-Corrosion of Reinforcing Steel in Concrete Slabs, Vol. 4: Galvanized Reinforcing Steel

DOT National Transportation Integrated Search

1981-12-01

Four-ft. by 5-ft. by 6-inch (1.2m x 1.5m x 0.15m) reinforced concrete slabs were fabricated, cured and subjected to 7 years of daily salting at an outdoor exposure yard. Subsequently, the slabs were modified and instrumented to allow direct measureme...

Mechanical properties of nanodiamond-reinforced hydroxyapatite composite coatings deposited by suspension plasma spraying

NASA Astrophysics Data System (ADS)

Chen, Xiuyong; Zhang, Botao; Gong, Yongfeng; Zhou, Ping; Li, Hua

2018-05-01

Hydroxyapatite (HA) coatings suffer from poor mechanical properties, which can be enhanced via incorporation of secondary bioinert reinforcement material. Nanodiamond (ND) possesses excellent mechanical properties to play the role as reinforcement for improving the mechanical properties of brittle HA bioceramic coatings. The major persistent challenge yet is the development of proper deposition techniques for fabricating the ND reinforced HA coatings. In this study, we present a novel deposition approach by plasma spraying the mixtures of ND suspension and micron-sized HA powder feedstock. The effect of ND reinforcement on the microstructure and the mechanical properties of the coatings such as hardness, adhesive strength and friction coefficient were examined. The results showed that the ND-reinforced HA coatings display lower porosity, fewer unmelted particles and uniform microstructure, in turn leading to significantly enhanced mechanical properties. The study presented a promising approach to fabricate ND-reinforced HA composite coatings on metal-based medical implants for potential clinical application.

76 FR 21333 - Laminated Woven Sacks From the People's Republic of China: Final Results of Second Antidumping...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-15

... the People's Republic of China: Final Results of Second Antidumping Duty Administrative Review AGENCY... from the People's Republic of China (``PRC''). See Laminated Woven Sacks From the People's Republic of... to these reviews are addressed in the ``Laminated Woven Sacks from the People's Republic of China...

Fabrication and Physical Evaluation of Gelatin-Coated Carbonate Apatite Foam

PubMed Central

Hara, Kanae; Fujisawa, Kenji; Nagai, Hirokazu; Takamaru, Natsumi; Ohe, Go; Tsuru, Kanji; Ishikawa, Kunio; Miyamoto, Youji

2016-01-01

Carbonate apatite (CO3Ap) foam has gained much attention in recent years because of its ability to rapidly replace bone. However, its mechanical strength is extremely low for clinical use. In this study, to understand the potential of gelatin-reinforced CO3Ap foam for bone replacement, CO3Ap foam was reinforced with gelatin and the resulting physical characteristics were evaluated. The mechanical strength increased significantly with the gelatin reinforcement. The compressive strength of gelatin-free CO3Ap foam was 74 kPa whereas that of the gelatin-reinforced CO3Ap foam, fabricated using 30 mass % gelatin solution, was approximately 3 MPa. Heat treatment for crosslinking gelatin had little effect on the mechanical strength of the foam. The gelatin-reinforced foam did not maintain its shape when immersed in a saline solution as this promoted swelling of the gelatin; however, in the same conditions, the heat-treated gelatin-reinforced foam proved to be stable. It is concluded, therefore, that heat treatment is the key to the fabrication of stable gelatin-reinforced CO3Ap foam. PMID:28773832

Fabrication and Physical Evaluation of Gelatin-Coated Carbonate Apatite Foam.

PubMed

Hara, Kanae; Fujisawa, Kenji; Nagai, Hirokazu; Takamaru, Natsumi; Ohe, Go; Tsuru, Kanji; Ishikawa, Kunio; Miyamoto, Youji

2016-08-23

Carbonate apatite (CO₃Ap) foam has gained much attention in recent years because of its ability to rapidly replace bone. However, its mechanical strength is extremely low for clinical use. In this study, to understand the potential of gelatin-reinforced CO₃Ap foam for bone replacement, CO₃Ap foam was reinforced with gelatin and the resulting physical characteristics were evaluated. The mechanical strength increased significantly with the gelatin reinforcement. The compressive strength of gelatin-free CO₃Ap foam was 74 kPa whereas that of the gelatin-reinforced CO₃Ap foam, fabricated using 30 mass % gelatin solution, was approximately 3 MPa. Heat treatment for crosslinking gelatin had little effect on the mechanical strength of the foam. The gelatin-reinforced foam did not maintain its shape when immersed in a saline solution as this promoted swelling of the gelatin; however, in the same conditions, the heat-treated gelatin-reinforced foam proved to be stable. It is concluded, therefore, that heat treatment is the key to the fabrication of stable gelatin-reinforced CO₃Ap foam.

Biaxial Testing of High-Strength Fabric Improves Design of Inflatable Radar Domes

NASA Technical Reports Server (NTRS)

Krause, David L.; Bartolotta, Paul A.

2001-01-01

Large radar installations around the globe continuously watch the skies, unobtrusively providing security to the United States; these systems have been in active use for the past 50 years. Often situated in extreme environments, the radar dishes require shielding from the harsh elements. Air-inflated domes (over 100 ft in diameter) are one structure of choice for providing this essential protection. The radomes are constructed from highstrength fabric that is strong enough to withstand the inflation pressure, high winds, and other environmental loads, yet transparent to the microwave signal to allow precise radar mapping. This fabric is woven from glass fibers for high strength and embedded in a polytetrafluoroethylene resin matrix, akin to the nonstick coatings used on cookware.

Fabrication And Evaluation Of Sic/Sic Tubes With Various Fiber Architectures

NASA Technical Reports Server (NTRS)

Yun, H. M.; DiCarlo, J. A.; Fox, D. S.

2003-01-01

SiC/SiC composites are excellent material candidates for high temperature applications where the performance requirements are high strength, high creep-rupture resistance, high environmental durability, and high thermal conductivity. In the past, the NASA UEET program has demonstrated fabrication of high-performance SiC/SiC flat panels reinforced by Sylramic-iBN SiC fibers. Currently NASA UEET is scaling up this SiC/SiC system by fabrication of more complex shaped components using the same fiber type. This paper reports the effects of various fiber architectures on the processing, mechanical, and durability behavior of small-diameter 0.5" ID SiC/SiC tubes, which are potential sub-elements for leading edges and cooling channels in turbine vanes and blades. Nine different fiber architectures were utilized for construction of seamless tube preforms, from simple 2D jelly-rolling to complex braiding, pin-weaving, filament-winding and 3D orthogonal weaving with approximately 5% fibers in the thru-thickness direction. Using the BN interphase and Sic matrix processing steps established for the flat panels, SiC/SiC tubes were fabricated with wall thicknesses of approximately 60 mils and total fiber fractions of approximately 35%. The "D" split ring tests for hoop tensile properties, micro-structural examinations for relationship between fiber architecture formation and matrix infiltration, and the low-pressure burner rig tests for the high temperature durability under thru-thickness thermal gradient were conducted. The better matrix infiltration and higher hoop strength were achieved using the tri-axial braided and the three-float pin woven SiC/SiC tubes. In general, it needs not only higher hoop direction fibers but also axial direction fibers for the higher hoop strength and the better infiltration, respectively. These results are analyzed to offer general guidelines for selecting fiber pre-form architectures and SiC/SiC processes that maximize tube hoop strength, thru

Powder-Coated Towpreg: Avenues to Near Net Shape Fabrication of High Performance Composites

NASA Technical Reports Server (NTRS)

Johnston, N. J.; Cano, R. J.; Marchello, J. M.; Sandusky, D. A.

1995-01-01

Near net shape parts were fabricated from powder-coated preforms. Key issues including powder loss during weaving and tow/tow friction during braiding were addressed, respectively, by fusing the powder to the fiber prior to weaving and applying a water-based gel to the towpreg prior to braiding. A 4:1 debulking of a complex 3-D woven powder-coated preform was achieved in a single step utilizing expansion rubber molding. Also, a process was developed for using powder-coated towpreg to fabricate consolidated ribbon having good dimensional integrity and low voids. Such ribbon will be required for in situ fabrication of structural components via heated head advanced tow placement. To implement process control and ensure high quality ribbon, the ribbonizer heat transfer and pulling force were modeled from fundamental principles. Most of the new ribbons were fabricated from dry polyarylene ether and polymide powders.

Micromechanical Characterization and Testing of Carbon Based Woven Thermal Protection Materials

NASA Technical Reports Server (NTRS)

Agrawal, Parul; Pham, John T.; Arnold, James O.; Peterson, Keith; Venkatapathy, Ethiraj

2013-01-01

Woven thermal protection system (TPS) materials are one of the enabling technologies for mechanically deployable hypersonic decelerator systems. These materials can be simultaneously used for thermal protection and as structural load bearing members during the entry, descent and landing operations. In order to ensure successful thermal and structural performance during the atmospheric entry, it is important to characterize the properties of these materials, once they have been subjected to entry like conditions. The present paper focuses on mechanical characteristics of pre-and post arc-jet tested woven TPS samples at different scales. It also presents the observations from scanning electron microscope and computed tomography images, and explains the changes in microstructure after being subjected to combined thermal-mechanical loading environments.

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

NASA Astrophysics Data System (ADS)

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

2013-05-01

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

Mg-Zn based composites reinforced with bioactive glass (45S5) fabricated via powder metallurgy

NASA Astrophysics Data System (ADS)

Ab llah, N.; Jamaludin, S. B.; Daud, Z. C.; Zaludin, M. A. F.

2016-07-01

Metallic implants are shifting from bio-inert to bioactive and biodegradable materials. These changes are made in order to improve the stress shielding effect and bio-compatibility and also avoid the second surgery procedure. Second surgery procedure is required if the patient experienced infection and implant loosening. An implant is predicted to be well for 15 to 20 years inside patient body. Currently, magnesium alloys are found to be the new biomaterials because of their properties close to the human bones and also able to degrade in the human body. In this work, magnesium-zinc based composites reinforced with different content (5, 15, 20 wt. %) of bioactive glass (45S5) were fabricated through powder metallurgy technique. The composites were sintered at 450˚C. Density and porosity of the composites were determined using the gas pycnometer. Microstructure of the composites was observed using an optical microscope. In-vitro bioactivity behavior was evaluated in the simulated body fluid (SBF) for 7 days. Fourier Transform Infrared (FTIR) was used to characterize the apatite forming on the samples surface. The microstructure of the composite showed that the pore segregated near the grain boundaries and bioglass clustering was observed with increasing content of bioglass. The true density of the composites increased with the increasing content of bioglass and the highest value of porosity was indicated by the Mg-Zn reinforced with 20 wt.% of bioglass. The addition of bio-glass to the Mg-Zn has also induced the formation of apatite layer after soaking in SBF solution.

Fiber-Reinforced Origamic Robotic Actuator.

PubMed

Yi, Juan; Chen, Xiaojiao; Song, Chaoyang; Wang, Zheng

2018-02-01

A novel pneumatic soft linear actuator Fiber-reinforced Origamic Robotic Actuator (FORA) is proposed with significant improvements on the popular McKibben-type actuators, offering nearly doubled motion range, substantially improved force profile, and significantly lower actuation pressure. The desirable feature set is made possible by a novel soft origamic chamber that expands radially while contracts axially when pressurized. Combining this new origamic chamber with a reinforcing fiber mesh, FORA generates very high traction force (over 150N) and very large contractile motion (over 50%) at very low input pressure (100 kPa). We developed quasi-static analytical models both to characterize the motion and forces and as guidelines for actuator design. Fabrication of FORA mostly involves consumer-grade three-dimensional (3D) printing. We provide a detailed list of materials and dimensions. Fabricated FORAs were tested on a dedicated platform against commercially available pneumatic artificial muscles from Shadow and Festo to showcase its superior performances and validate the analytical models with very good agreements. Finally, a robotic joint was developed driven by two antagonistic FORAs, to showcase the benefits of the performance improvements. With its simple structure, fully characterized mechanism, easy fabrication procedure, and highly desirable performance, FORA could be easily customized to application requirements and fabricated by anyone with access to a 3D printer. This will pave the way to the wider adaptation and application of soft robotic systems.

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

NASA Technical Reports Server (NTRS)

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

KSC-06pd0576

NASA Image and Video Library

2006-04-05

KENNEDY SPACE CENTER, FLA. - In Orbiter Processing Facility bay 2 at NASA's Kennedy Space Center, workers maneuver the reinforced carbon-carbon nose cap as it is hoisted into the air. The nose cap will be installed on Endeavour. The nose cap is insulated with thermal protection system blankets made of a woven ceramic fabric. The special blankets help insulate the vehicle's nose cap and protect it from the extreme temperatures it will face during a mission. Photo credit: NASA/Jim Grossmann

Long-term Isothermal Aging Effects on Weight Loss, Compression Properties, and Dimensions of T650-35 Fabric-reinforced PMR-15 Composites-data

NASA Technical Reports Server (NTRS)

Bowles, Kenneth J.; Tsuji, Luis; Kamvouris, John; Roberts, Gary D.

2003-01-01

A cooperative program was conducted with the General Electric Aircraft Engines plant in Evendale, Ohio, to study the effects of long-term isothermal aging at elevated temperatures on compression and thermal durability properties of T650 35 fabric-reinforced PMR 15 composites. This degradation study was conducted over an approximate time period of 3 1/2 yr. The aging temperatures were 204, 260, 288, 316, and 343 C. Specimens of different dimensions were evaluated. Specimens with ratios of the cut edge to total surface area of 0.03 to 0.89 were fabricated and aged. The aged and unaged specimens were tested in compression as specified in Test Method for Compressive Properties of Rigid Plastics (ASTM D695M). Thickness changes, degraded surface layer growth, weight loss, and failure modes were monitored and recorded. All property changes were thickness dependent.

The investigation on the structure, fabrication and applications of graphene

NASA Astrophysics Data System (ADS)

Du, Donghe

By investigating the structure of graphene oxide (GO), the long-wavelength photoluminescence of GO is evidenced to be originated from the excimer formation between GO basal plane and oxidative debris (ODs) attached on the GO sheets. The thermally unstable ODs would induce micro-explosion of GO upon heating. A novel method is developed to supress the explosion and achieve simultaneous thermal reduction and nitrogen doping of graphene oxide in air. The high quality N-doped graphene demonstrate excellent electrocatalytic property in oxygen reduction reaction. Furthermore, an electronic textile material is fabricated by coating chemically reduced GO on a piece of non-woven fabric (GNWF). GNWF can be applied as wearable sensors to detect physiological signals of human body. This research work deepens the understanding on the structure and property of graphene based materials and provides a cost-effective fabrication method for large scale production of graphene, and hence facilitates the commercialization of graphene.

Electrically and Thermally Conductive Carbon Fibre Fabric Reinforced Polymer Composites Based on Nanocarbons and an In-situ Polymerizable Cyclic Oligoester.

PubMed

Jang, Ji-Un; Park, Hyeong Cheol; Lee, Hun Su; Khil, Myung-Seob; Kim, Seong Yun

2018-05-16

There is growing interest in carbon fibre fabric reinforced polymer (CFRP) composites based on a thermoplastic matrix, which is easy to rapidly produce, repair or recycle. To expand the applications of thermoplastic CFRP composites, we propose a process for fabricating conductive CFRP composites with improved electrical and thermal conductivities using an in-situ polymerizable and thermoplastic cyclic butylene terephthalate oligomer matrix, which can induce good impregnation of carbon fibres and a high dispersion of nanocarbon fillers. Under optimal processing conditions, the surface resistivity below the order of 10 +10 Ω/sq, which can enable electrostatic powder painting application for automotive outer panels, can be induced with a low nanofiller content of 1 wt%. Furthermore, CFRP composites containing 20 wt% graphene nanoplatelets (GNPs) were found to exhibit an excellent thermal conductivity of 13.7 W/m·K. Incorporating multi-walled carbon nanotubes into CFRP composites is more advantageous for improving electrical conductivity, whereas incorporating GNPs is more beneficial for enhancing thermal conductivity. It is possible to fabricate the developed thermoplastic CFRP composites within 2 min. The proposed composites have sufficient potential for use in automotive outer panels, engine blocks and other mechanical components that require conductive characteristics.

Design, Analysis and Fabrication of Secondary Structural Components for the Habitat Demonstration Unit-Deep Space Habitat

NASA Technical Reports Server (NTRS)

Smith, Russell W.; Langford, William M.

2012-01-01

In support of NASA s Habitat Demonstration Unit - Deep Space Habitat Prototype, a number of evolved structural sections were designed, fabricated, analyzed and installed in the 5 meter diameter prototype. The hardware consisted of three principal structural sections, and included the development of novel fastener insert concepts. The articles developed consisted of: 1) 1/8th of the primary flooring section, 2) an inner radius floor beam support which interfaced with, and supported (1), 3) two upper hatch section prototypes, and 4) novel insert designs for mechanical fastener attachments. Advanced manufacturing approaches were utilized in the fabrication of the components. The structural components were developed using current commercial aircraft constructions as a baseline (for both the flooring components and their associated mechanical fastener inserts). The structural sections utilized honeycomb sandwich panels. The core section consisted of 1/8th inch cell size Nomex, at 9 lbs/cu ft, and which was 0.66 inches thick. The facesheets had 3 plys each, with a thickness of 0.010 inches per ply, made from woven E-glass with epoxy reinforcement. Analysis activities consisted of both analytical models, as well as initial closed form calculations. Testing was conducted to help verify analysis model inputs, as well as to facilitate correlation between testing and analysis. Test activities consisted of both 4 point bending tests as well as compressive core crush sequences. This paper presents an overview of this activity, and discusses issues encountered during the various phases of the applied research effort, and its relevance to future space based habitats.

Low-cost and large-scale flexible SERS-cotton fabric as a wipe substrate for surface trace analysis

NASA Astrophysics Data System (ADS)

Chen, Yanmin; Ge, Fengyan; Guang, Shanyi; Cai, Zaisheng

2018-04-01

The large-scale surface enhanced Raman scattering (SERS) cotton fabrics were fabricated based on traditional woven ones using a dyeing-like method of vat dyes, where silver nanoparticles (Ag NPs) were in-situ synthesized by 'dipping-reducing-drying' process. By controlling the concentration of AgNO3 solution, the optimal SERS cotton fabric was obtained, which had a homogeneous close packing of Ag NPs. The SERS cotton fabric was employed to detect p-Aminothiophenol (PATP). It was found that the new fabric possessed excellent reproducibility (about 20%), long-term stability (about 57 days) and high SERS sensitivity with a detected concentration as low as 10-12 M. Furthermore, owing to the excellent mechanical flexibility and good absorption ability, the SERS cotton fabric was employed to detect carbaryl on the surface of an apple by simply swabbing, which showed great potential in fast trace analysis. More importantly, this study may realize large-scale production with low cost by a traditional cotton fabric.

Notch Sensitivity of Woven Ceramic Matrix Composites Under Tensile Loading: An Experimental, Analytical, and Finite Element Study

NASA Technical Reports Server (NTRS)

Haque, A.; Ahmed, L.; Ware, T.; Jeelani, S.; Verrilli, Michael J. (Technical Monitor)

2001-01-01

The stress concentrations associated with circular notches and subjected to uniform tensile loading in woven ceramic matrix composites (CMCs) have been investigated for high-efficient turbine engine applications. The CMC's were composed of Nicalon silicon carbide woven fabric in SiNC matrix manufactured through polymer impregnation process (PIP). Several combinations of hole diameter/plate width ratios and ply orientations were considered in this study. In the first part, the stress concentrations were calculated measuring strain distributions surrounding the hole using strain gages at different locations of the specimens during the initial portion of the stress-strain curve before any microdamage developed. The stress concentration was also calculated analytically using Lekhnitskii's solution for orthotropic plates. A finite-width correction factor for anisotropic and orthotropic composite plate was considered. The stress distributions surrounding the circular hole of a CMC's plate were further studied using finite element analysis. Both solid and shell elements were considered. The experimental results were compared with both the analytical and finite element solutions. Extensive optical and scanning electron microscopic examinations were carried out for identifying the fracture behavior and failure mechanisms of both the notched and notched specimens. The stress concentration factors (SCF) determined by analytical method overpredicted the experimental results. But the numerical solution underpredicted the experimental SCF. Stress concentration factors are shown to increase with enlarged hole size and the effects of ply orientations on stress concentration factors are observed to be negligible. In all the cases, the crack initiated at the notch edge and propagated along the width towards the edge of the specimens.

Assessment of damage in 'green' composites

NASA Astrophysics Data System (ADS)

Malinowski, Paweł H.; Ostachowicz, Wiesław M.; Touchard, Fabienne; Boustie, Michel; Chocinski-Arnault, Laurence; Pascual Gonzalez, Pedro; Berthe, Laurent; de Vasconcellos, Davi; Sorrentino, Luigi

2017-04-01

The behaviour of eco-composites, when subjected to laser or mechanical impact loadings, is not well known yet. A research was proposed looking at the behaviour of `green' and synthetic composites under impact loading. The study was focused on composites reinforced with short, medium and long fibres. Short fibre composites were made of spruce fibres and ABS. The fibres were used both as received and after a thermal treatment. Another set of samples was made of 60 mm-long flax fibres. Two types of thermoplastic polymers were used as matrices: polypropylene and polylactide. Also a woven eco-composite was investigated. It was made of plain woven hemp fabric impregnated with epoxy resin. A fully synthetic woven composite, used as reference laminate for comparison with `green' composites, was prepared by using a plain weave woven glass fabric impregnated with epoxy resin. Mechanical impacts were performed by means of a falling dart impact testing machine. The specimens were tested at different impact energy levels (from 1J to 5J) by keeping constant the mass of the impactor and varying the drop height. Laser impact tests were performed by means of a high power laser shock facility. All the samples were tested at six different laser shock intensities, keeping constant the shock diameter and the pulse duration. Six assessment techniques were employed in order to analyse and compare impact damages: eye observation, back face relief, terahertz spectroscopy, laser vibrometry, X-ray micro-tomography and microscopic observations. Different damage detection thresholds for each material and technique were obtained.

Reinforce Design and Construction Issues with a Comprehensive Laboratory Project.

ERIC Educational Resources Information Center

Schemmel, John J.

In 1996, a comprehensive project was introduced in the first course of Reinforced Concrete Design, CVEG 4303 at the University of Arkansas. The primary purpose of this project was to highlight issues related to the construction of reinforced concrete elements. This semester-long project involves the design, fabrication, and testing of 8-foot long…

Carbon Nanotube-Reinforced Thermotropic Liquid Crystal Polymer Nanocomposites

PubMed Central

Kim, Jun Young

2009-01-01

This paper focuses on the fabrication via simple melt blending of thermotropic liquid crystal polyester (TLCP) nanocomposites reinforced with a very small quantity of modified carbon nanotube (CNT) and the unique effects of the modified CNT on the physical properties of the nanocomposites. The thermal, mechanical, and rheological properties of modified CNT-reinforced TLCP nanocomposites are highly dependent on the uniform dispersion of CNT and the interactions between the CNT and TLCP, which can be enhanced by chemical modification of the CNT, providing a design guide of CNT-reinforced TLCP nanocomposites with great potential for industrial uses.

Laminates and reinforced metals

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1980-01-01

A selective review is presented of the state of the art of metallic laminates and fiber reinforced metals called metallic matrix laminates (MMLs). Design and analysis procedures that are used for, and typical structural components that have been made from MMLs are emphasized. Selected MMLs, constituent materials, typical material properties and fabrication procedures are briefly described, including hybrids and superhybrids. Advantages, disadvantages, and special considerations required during design, analysis, and fabrication of MMLs are examined. Tabular and graphical data are included to illustrate key aspects of MMLs. Appropriate references are cited to provide a selective bibliography of a rapidly expanding and very promising research and development field.

Diagnostics of glass fiber reinforced polymers and comparative analysis of their fabrication techniques with the use of acoustic emission

NASA Astrophysics Data System (ADS)

Bashkov, O. V.; Bryansky, A. A.; Panin, S. V.; Zaikov, V. I.

2016-11-01

Strength properties of the glass fiber reinforced polymers (GFRP) fabricated by vacuum and vacuum autoclave molding techniques were analyzed. Measurements of porosity of the GFRP parts manufactured by various molding techniques were conducted with the help of optical microscopy. On the basis of experimental data obtained by means of acoustic emission hardware/software setup, the technique for running diagnostics and forecasting the bearing capacity of polymeric composite materials based on the result of three-point bending tests has been developed. The operation principle of the technique is underlined by the evaluation of the power function index change which takes place on the dependence of the total acoustic emission counts versus the loading stress.

Long-term follow-up of aneurysms treated electively with woven stent-assisted coiling.

PubMed

Cheung, Nicholas K; Chiu, Albert Hy; Cheung, Andrew K; Wenderoth, Jason D

2017-12-15

Preliminary short-term results for stent-assisted coil embolization (SACE) using woven/braided stents have been promising. However, evidence supporting mid- to long-term efficacy and durability is lacking. To report the long-term results for the durability of elective intracranial aneurysms treated with woven stents. Between May 2012 and May 2015, 98 consecutive patients with 103 aneurysms underwent elective woven SACE across three Australian neurovascular centres. All patients had immediate, 6- and 18-month clinical and radiological follow-up. Radiological assessment was performed with modified Raymond-Roy occlusion scores based on angiography results, while clinical assessment was based on the modified Rankin Scale. Six-month follow-up was available in 100 aneurysms, and an 18-month follow-up in 97 aneurysms. Total occlusion rates of 82% were achieved at inception, 82% at 6 months, and 90% at 18 months. Satisfactory occlusion with small neck remnants was present in 17% at inception, 16% at 6 months, and 9% at 18 months. Good neurological outcomes were achieved in 95% at 18 months. Intraprocedural thromboembolic events were recorded in 3% and delayed events in 1% (all in patients taking clopidogrel). Aneurysm recurrence occurred in one patient (1%). Technical complications occurred in 5%. The total complication rate was 10%. Woven SACE is safe, efficacious, and durable at long-term 18-month follow-up, with very low recurrence and re-treatment rates. Preliminary results appear better than those for traditional laser-cut stents. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Elastic properties of woven bone: effect of mineral content and collagen fibrils orientation.

PubMed

García-Rodríguez, J; Martínez-Reina, J

2017-02-01

Woven bone is a type of tissue that forms mainly during fracture healing or fetal bone development. Its microstructure can be modeled as a composite with a matrix of mineral (hydroxyapatite) and inclusions of collagen fibrils with a more or less random orientation. In the present study, its elastic properties were estimated as a function of composition (degree of mineralization) and fibril orientation. A self-consistent homogenization scheme considering randomness of inclusions' orientation was used for this purpose. Lacuno-canalicular porosity in the form of periodically distributed void inclusions was also considered. Assuming collagen fibrils to be uniformly oriented in all directions led to an isotropic tissue with a Young's modulus [Formula: see text] GPa, which is of the same order of magnitude as that of woven bone in fracture calluses. By contrast, assuming fibrils to have a preferential orientation resulted in a Young's modulus in the preferential direction of 9-16 GPa depending on the mineral content of the tissue. These results are consistent with experimental evidence for woven bone in foetuses, where collagen fibrils are aligned to a certain extent.

Vision-based in-line fabric defect detection using yarn-specific shape features

NASA Astrophysics Data System (ADS)

Schneider, Dorian; Aach, Til

2012-01-01

We develop a methodology for automatic in-line flaw detection in industrial woven fabrics. Where state of the art detection algorithms apply texture analysis methods to operate on low-resolved ({200 ppi) image data, we describe here a process flow to segment single yarns in high-resolved ({1000 ppi) textile images. Four yarn shape features are extracted, allowing a precise detection and measurement of defects. The degree of precision reached allows a classification of detected defects according to their nature, providing an innovation in the field of automatic fabric flaw detection. The design has been carried out to meet real time requirements and face adverse conditions caused by loom vibrations and dirt. The entire process flow is discussed followed by an evaluation using a database with real-life industrial fabric images. This work pertains to the construction of an on-loom defect detection system to be used in manufacturing practice.

Preliminary evaluation of fiber composite reinforcement of truck frame rails

NASA Technical Reports Server (NTRS)

Faddoul, J. R.

1977-01-01

The use of graphite fiber/resin matrix composite to effectively reinforce a standard steel truck frame rail is studied. A preliminary design was made and it was determined that the reinforcement weight could be reduced by a factor of 10 when compared to a steel reinforcement. A section of a 1/3 scale reinforced rail was fabricated to demonstrate low cost manufacturing techniques. The scale rail section was then tested and increased stiffness was confirmed. No evidence of composite fatigue was found after 500,000 cycles to a fiber stress of 34,000 psi. The test specimen failed in bending in a static test at a load 50 percent greater than that predicted for a non-reinforced rail.

Musculoskeletal Problems in Iranian Hand-Woven Shoe-Sole Making Operation and Developing Guidelines for Workstation Design.

PubMed

Veisi, H; Choobineh, A R; Ghaem, H

2016-04-01

Musculoskeletal disorders (MSDs) are among important health problems in working population. Because of performing difficult physical activities, hand-woven shoe-sole makers are at risk of developing various types of MSDs. To determine the prevalence of musculoskeletal symptoms in different body areas of hand-woven shoe-sole makers, assess workers' postures and workstations, evaluate ergonomic and individual factors associated with MSDs, and develop guidelines for designing hand-woven shoe-sole making workstation. In this cross-sectional study, the prevalence of MSDs symptoms and their risk factors were studied among 240 hand-woven shoe-sole makers. Working posture and workstations were ergonomically assessed as well. The data were collected through interviewing and using Nordic musculoskeletal questionnaire and by direct observation of posture using RULA method. Logistic regression analysis was used to determine risk factors associated with MSDs symptoms. The prevalence and severity of MSDs symptoms were high among the study population. Ergonomic factors including daily working time, working posture, and force exertion, as well as individual factors, such as age, job tenure, and education were significantly associated with MSDs symptoms. It seems that the majority of ergonomics shortcomings originate from poorly designed workstation. Some general guidelines for designing shoe-sole making workstation are presented.

Fabrication and wear test of a continuous fiber/particulate composite total surface hip replacement

NASA Technical Reports Server (NTRS)

Roberts, J. C.; Ling, F. F.; Jones, W. R., Jr.

1981-01-01

Continuous fiber woven E-glass composite femoral shells having the ame elastic properties as bone were fabricated. The shells were then encrusted with filled epoxy wear resistant coatings and run dry against ultrahigh molecular weight polyethylene acetabular cups in 42,000 and 250,000 cycle were tests on a total hip simulator. The tribological characteristics of these shells atriculating with the acetabular cups are comparable to a vitallium bal articulating with an ultrahigh molecular weight polyethylene cup.

Durability Characteristics Analysis of Plastic Worm Wheel with Glass Fiber Reinforced Polyamide.

PubMed

Kim, Gun-Hee; Lee, Jeong-Won; Seo, Tae-Il

2013-05-10

Plastic worm wheel is widely used in the vehicle manufacturing field because it is favorable for weight lightening, vibration and noise reduction, as well as corrosion resistance. However, it is very difficult for general plastics to secure the mechanical properties that are required for vehicle gears. If the plastic resin is reinforced by glass fiber in the fabrication process of plastic worm wheel, it is possible to achieve the mechanical properties of metallic material levels. In this study, the mechanical characteristic analysis of the glass-reinforced plastic worm wheel, according to the contents of glass fiber, is performed by analytic and experimental methods. In the case of the glass fiber-reinforced resin, the orientation and contents of glass fibers can influence the mechanical properties. For the characteristic prediction of plastic worm wheel, computer-aided engineering (CAE) analysis processes such as structural and injection molding analysis were executed with the polyamide resin reinforcement glass fiber (25 wt %, 50 wt %). The injection mold for fabricating the prototype plastic worm wheel was designed and made to reflect the CAE analysis results. Finally, the durability of prototype plastic worm wheel fabricated by the injection molding process was evaluated by the experimental method and the characteristics according to the glass fiber contents.

Durability Characteristics Analysis of Plastic Worm Wheel with Glass Fiber Reinforced Polyamide

PubMed Central

Kim, Gun-Hee; Lee, Jeong-Won; Seo, Tae-Il

2013-01-01

Plastic worm wheel is widely used in the vehicle manufacturing field because it is favorable for weight lightening, vibration and noise reduction, as well as corrosion resistance. However, it is very difficult for general plastics to secure the mechanical properties that are required for vehicle gears. If the plastic resin is reinforced by glass fiber in the fabrication process of plastic worm wheel, it is possible to achieve the mechanical properties of metallic material levels. In this study, the mechanical characteristic analysis of the glass-reinforced plastic worm wheel, according to the contents of glass fiber, is performed by analytic and experimental methods. In the case of the glass fiber-reinforced resin, the orientation and contents of glass fibers can influence the mechanical properties. For the characteristic prediction of plastic worm wheel, computer-aided engineering (CAE) analysis processes such as structural and injection molding analysis were executed with the polyamide resin reinforcement glass fiber (25 wt %, 50 wt %). The injection mold for fabricating the prototype plastic worm wheel was designed and made to reflect the CAE analysis results. Finally, the durability of prototype plastic worm wheel fabricated by the injection molding process was evaluated by the experimental method and the characteristics according to the glass fiber contents. PMID:28809248

Composite strengthening. [of nonferrous, fiber reinforced alloys

NASA Technical Reports Server (NTRS)

Stoloff, N. S.

1976-01-01

The mechanical behavior of unidirectionally reinforced metals is examined, with particular attention to fabrication techniques for artificial composites and eutectic alloys and to principles of fiber reinforcement. The properties of artificial composites are discussed in terms of strength of fiber composites, strength of ribbon-reinforced composites, crack initiation, crack propagation, and creep behavior. The properties of eutectic composites are examined relative to tensile strength, compressive strength, fracture, high-temperature strength, and fatigue. In the case of artificial composites, parallelism of fibers, good bonding between fibers and matrix, and freedom of fibers from damage are all necessary to ensure superior performance. For many eutectic systems there are stringent boundary conditions relative to melt purity and superheat, atmosphere control, temperature gradient, and growth rate in order to provide near-perfect alignment of the reinforcements with a minimum of growth defects.

Recent progress in NASA Langley textile reinforced composites program

NASA Technical Reports Server (NTRS)

Dexter, H. Benson; Harris, Charles E.; Johnston, Norman J.

1992-01-01

The NASA LaRC is conducting and sponsoring research to explore the benefits of textile reinforced composites for civil transport aircraft primary structures. The objective of this program is to develop and demonstrate the potential of affordable textile reinforced composite materials to meet design properties and damage tolerance requirements of advanced aircraft structural concepts. In addition to in-house research, the program was recently expanded to include major participation by the aircraft industry and aerospace textile companies. The major program elements include development of textile preforms, processing science, mechanics of materials, experimental characterization of materials, and development and evaluation of textile reinforced composite structural elements and subcomponents. The NASA Langley in-house focus is as follows: development of a science-based understanding of resin transfer molding (RTM), development of powder-coated towpreg processes, analysis methodology, and development of a performance database on textile reinforced composites. The focus of the textile industry participation is on development of multidirectional, damage-tolerant preforms, and the aircraft industry participation is in the areas of design, fabrication and testing of textile reinforced composite structural elements and subcomponents. Textile processes such as 3D weaving, 2D and 3D braiding, and knitting/stitching are being compared with conventional laminated tape processes for improved damage tolerance. Through-the-thickness reinforcements offer significant damage tolerance improvements. However, these gains must be weighed against potential loss in in-plane properties such as strength and stiffness. Analytical trade studies are underway to establish design guidelines for the application of textile material forms to meet specific loading requirements. Fabrication and testing of large structural components are required to establish the full potential of textile reinforced