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会议名称:

American Society for Composites technical conference

召开年:

2017

召开地:

West Lafayette

会议文集:

Proceedings of the American Society for Composites thirty-second technical conference: American Society for Composites thirty-second technical conference (ASC), October 23-25 2017, West Lafayette, Indiana, USA

主办单位:

American Society for Composites

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  • 题名 作者 来源 发表时间 操作
  • Peridynamics for Progressive Failure Analysis of Composites

    作者:ERDOGAN MADENCI;MEHMET DORDUNCU;NAM PHAN; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    This study applies the Peridynamic Differential Operator (PDDO) to solve for the equilibrium equations of Classical Laminate Theory (CLT) for progressive failure analysis of composites without employing a stiffness degradation factor. The PD representation of the displacement derivatives and the transformed reduced stiffness matrix permits the evolution of fiber and matrix cracking during deformation, and enables the modeling of progressive failure. In the derivation of equilibrium equations of CLT, the transformed reduced stiffness matrix is considered as spatially varying unlike the common assumption of its uniform variation. The PD representation of these equations enables the modeling of progressive failure during the deformation through the removal of PD interactions (bonds). The stiffness degradation is natural, and it is achieved by removing the PD bonds. The numerical results concern unidirectional laminates and a symmetric cross-ply laminate with a through-the-thickness crack under tension, and a nonsymmetric cross-ply laminate with a crack only in the bottom ply subjected to a uniform distributed load.

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  • Peridynamics for Progressive Failure Analysis of Composites

    ERDOGAN MADENCI;MEHMET DORDUNCU;NAM PHAN;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Atomistic Design of Carbon Nanotube Junctions of Arbitrary Junction Geometry

    作者:VIKAS VARSHNEY;VINU UNNIKRISHNAN;JONGHOON LEE;SANGWOOK SIHN;AJIT K. ROY; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    Creating any workable materials construct for any viable applications using carbon or any other nanotubes would invariable involve dispersion of the nanotube in either twodimensional spatial mesh or three-dimensional volumetric space. These dispersed nanotubes invariably are interconnected via overlap or junctions. It is known that the atomic configuration of these nanotube junctions critically influence the bulk properties (structural, thermal, electrical, dielectric). Thus, it is extremely important to pay a close attention to how optimally these junctions can be formed to attain the desirable properties. In all practical situations, experimentally synthesized junctions (either single CNT junctions or junctions in 2D and 3D CNT network structures) are expected to have random orientation of defect sites (non-hexagonal rings) around the junction. Such random nature of junctions’ topology and defect characteristics is expected to affect their strength and durability as well as have impact on associated mesoscopic and macroscopic properties. In this work, we present a generic framework on creating junctions between CNTs with arbitrary spatial (orientation and degree of overlap) and intrinsic (chirality) specifications, as well as to tune degree of topological defects around the junction via a variety of defect annihilation approaches. Our method makes use of the primal/dual meshing concept where the development and manipulation of the junction nodes occur using a triangular meshes (primal mesh), which is eventually converted to its dual (honeycomb mesh) to render a fully-covalently bonded CNT junction where each carbon atom has 3 bonded neighbors (mimicking sp¬2 hybridization). This design approach offers an opportunity to investigate the effect of topological arrangement of defects around the junction on mechanical, electrical and thermal properties. In addition, this junction design methodology is applied to a CNT-graphene junction and to study the effect of local carbon defects (pentagonal or heptagonal carbon ring versus the hexagonal) on junction strength. It is observed that a symmetrical distribution of carbon ring defects around the CNT-graphene junction yield higher strength that that of irregular defect distribution.

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  • Atomistic Design of Carbon Nanotube Junctions of Arbitrary Junction Geometry

    VIKAS VARSHNEY;VINU UNNIKRISHNAN;JONGHOON LEE;SANGWOOK SIHN;AJIT K. ROY;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Draping Behavior of Non-Crimp Fabrics

    作者:WILLIAM R. RODGERS;PRAVEEN PASUPULETI;SELINA ZHAO;ARNAUD DEREIMS;MARK DOROUDIAN;VENKAT AITHARAJU; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    Non-crimp fabric (NCF) preforms are an attractive alternative to traditional preimpregnated tapes due to their low manufacturing cost and high efficiency. The orientation of the fibers in each layer can be tailored, independent of the other layers, to optimize the required load carrying capacity in that particular direction, making them capable of improved performance. Stitches help to keep the fiber tows in the NCF fabric straight during handling; however, the stitches prevent the fibers from reorienting easily to accommodate complex shapes without wrinkling. In order for NCF fabrics to be used to create complex geometric shapes, their draping behavior needs to be understood with respect to different fabric variables so that the draping performance can be maximized. To date, the draping behavior of NCF fabrics has been only sparsely investigated in contrast to the amount of research reported on woven fabrics. This paper presents an investigation on the role of fabric architecture in the formability of NCF fabrics. This study is a subset of a broad study conducted under the purview of a Department of Energy project funded to General Motors for developing state of the art computational tools for integrated manufacturing and structural performance prediction of carbon fiber composites. For modeling the draping behavior, fabric characterization tests such as bending and bias-extension evaluations were conducted for NCF fabrics with varying areal weights and construction. Taking advantage of ESI’s PAM-FORM material model, asymmetric shear behavior was included in conjunction with different membrane and bending behavior to model the draping behavior of these fabrics. For this study, the fabric characterization data was first used to calibrate the draping models in simple shear and bending tests. Later these models were validated against the deformation of the fabrics when they were formed using a truncated pyramid tool designed at the General Motors Research Labs to assess the drapeability of the dry fabrics.

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  • Draping Behavior of Non-Crimp Fabrics

    WILLIAM R. RODGERS;PRAVEEN PASUPULETI;SELINA ZHAO;ARNAUD DEREIMS;MARK DOROUDIAN;VENKAT AITHARAJU;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Analytical Prediction of Tensile Strength for Two-Dimensional Triaxially Braided Composite

    作者:HAOYUAN DANG;PENG LIU;ZHENQIANG ZHAO;YULONG LI;CHAO ZHANG; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    In this paper, a new analytical model is developed to predict the strength of two-dimensional triaxial braided composite (2DTBC). According to the concept of subcell model, a representative unit cell of braided composite is divided into four subcells, each of which is approximated as a stack of unidirectional composite plies. In order to investigate the interaction of braided angle and effective properties, it is assumed that the unit cell models of different braid angles have the same fiber volume fraction and the same thickness. Then, explicit equations can be obtained to describe the geometric parameters and to quantify the specific dimensions of subcell components based on the manufacture provided properties and microscopic image analysis of realistic specimens. Micro-mechanical models are applied to estimate the elastic and strength properties of unidirectional plies. Classical Laminate theory and Parallel and Series Bridge models are implemented to connect the strain and stress responses of subcell components and effective responses of the unit cell. Hoffman and Hashin failure criteria are used to examine the onset of failure for each subcell component, which can then predict the progressive failure process and global stress-strain response of the unit cell. The developed analytical model will then be utilized to predict the tensile strength (axial tension and transverse tension) of a +60°/0°/-60° 2DTBC and validated against experiments. Finally, the validated model will be used to study strength properties for 2DTBC of different braided angles. The results can provide insights for the design and optimization of composite structures with similar braided architecture.

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  • Analytical Prediction of Tensile Strength for Two-Dimensional Triaxially Braided Composite

    HAOYUAN DANG;PENG LIU;ZHENQIANG ZHAO;YULONG LI;CHAO ZHANG;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Verification and Validation of a Generalized Orthotropic Material Model MAT213 Implemented in LS-DYNA

    作者:LOUKHAM SHYAMSUNDER;BILAL KHALED;NATHAN HOLT;CANIO HOFFARTH;SUBRAMANIAM RAJAN;ROBERT GOLDBERG;KELLY S. CARNEY;PAUL DUBOIS;GUNTHER BLANKENHORN; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    A general orthotropic material model has been developed which is suitable for impact analysis. The material model is driven by tabulated data rather than point-wise material properties data, and has been implemented into LS-DYNA. The stress-strain behavior of a material is one of the input tabulated data used to drive the material model which can be obtained either from experiment or virtual testing or a combination of both. The material model consists of three sub-models – deformation, damage and failure. The implementation of the sub-models and some of the salient features are presented in this paper. The second part of the paper presents some of the validation tests carried out using a unidirectional fiber reinforced composite, T800/F3900.

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  • Verification and Validation of a Generalized Orthotropic Material Model MAT213 Implemented in LS-DYNA

    LOUKHAM SHYAMSUNDER;BILAL KHALED;NATHAN HOLT;CANIO HOFFARTH;SUBRAMANIAM RAJAN;ROBERT GOLDBERG;KELLY S. CARNEY;PAUL DUBOIS;GUNTHER BLANKENHORN;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Tensile and Compressive Failure Behaviors of Triaxially Braided Composite

    作者:ZHENQIANG ZHAO;CHAO ZHANG;YULONG LI; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    The failure mechanisms of triaxially braided composite under in-plane tensile and compression loads are investigated in this study. The testing specimens are cut from a typical 8-layer 0°/±60° triaxially braided composite panel which is fabricated with Toray T700 carbon fiber and a toughened epoxy resin 3266. The quasi-static tension and compression loads that parallel or vertical to the 0° fibers are applied by using a Hydraulic testing machine, respectively. The Digital Image Correlation (DIC) technology is implemented to measure the displacement and strain fields of gauge section for both the tensile and compression tests. As a result, the failure mechanisms under different load conditions are elaborated contrastively.

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  • Tensile and Compressive Failure Behaviors of Triaxially Braided Composite

    ZHENQIANG ZHAO;CHAO ZHANG;YULONG LI;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Creating Flexible Structures Out of MDF Plates

    作者:RENZHE CHEN;MINGLIANG JIANG;NEGAR KALANTAR;MICHAEL MORENO;ANASTASIA MULIANA; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    Medium densify fiberboard (MDF) is a composite comprising of wood fibers and epoxy resin, with a typical density range between 600-800 kg/m3. It is currently used for secondary structures in buildings such as architectural walls and facades. MDFs are typically available in flat panel forms which can be cut into various shapes for architectural design purposes. One cutting method is known as kerfing, in which a series of cuts are made on a wood panel to create flexible structures mainly through bending and twisting deformations. In this study, we present a micromechanics model of cut patterns in order to understand the overall deformations of the kerf panel. Three different cut densities, i.e., one, two, and three cuts per quarter unit-cell, of a square spiral pattern are studied. The effect of different cut densities on the uniaxial stretching of the unit-cell is examined. An experimental test is also done on a unit-cell under uniaxial stretching. The responses from the experiment and model are compared.

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  • Creating Flexible Structures Out of MDF Plates

    RENZHE CHEN;MINGLIANG JIANG;NEGAR KALANTAR;MICHAEL MORENO;ANASTASIA MULIANA;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Multi-Scale Evaluation for Effect of Reinforcements on Viscoelasticity of Shape-Memory Polymer Composites

    作者:YUTA NAITO;SHIMPEI MATSUDA;MASAAKI NISHIKAWA;NAOKI MATSUDA;MASAKI HOJO; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    The present study investigated the effect of reinforcement on the viscoelasticity of shape-memory polymer composites (SMPCs) from two different scale views utilizing two different techniques. From a nano-scale view, we conducted dynamic viscoelastic simulations using molecular mechanics simulation models proposed by our research group . These nano-scale simulations could reproduce a clear glass transition from glassy state to rubbery state in the frequency domain; therefore, they are suitable for studying the filler effect including interface properties. From a macro-scale view, we conducted experiment dynamic mechanical analysis using woven fabric based SMPCs. Through comparison of multi-scale analyses, we investigated the importance of nano-scale analysis for the composites’ design of viscoelasticity.

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  • Multi-Scale Evaluation for Effect of Reinforcements on Viscoelasticity of Shape-Memory Polymer Composites

    YUTA NAITO;SHIMPEI MATSUDA;MASAAKI NISHIKAWA;NAOKI MATSUDA;MASAKI HOJO;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Effect of Consolidation Pressure on the Transverse Compressive Strength of UHMWPE Composites at High Strain-rates

    作者:JASON C. PARKER;K.T. RAMESH; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    UHMWPE (Ultra-High Molecular Weight Polyethylene) composites are commonly utilized as protective materials against fragments and projectiles. They are composed of UHMWPE fibers and a thermoplastic elastomeric matrix, typically Styrene- Isoprene-Styrene (SIS) or Thermoplastic Polyurethane (TPU). The dynamic mechanical performance of these composites is known to scale with consolidation pressure, but the underlying mechanisms are poorly understood. The majority of the experiments on this material described in the literature are performed at quasi-static strain-rates, even though the composite is loaded at ballistic strain-rates (10~5 – 10~6 s~(-1)) when used in protective applications. In this work, Dyneema® HB80 laminates consolidated at two different pressures are loaded in uniaxial out-of-plane compression at strain rates of the order of 10~3 s~(-1) in a Kolsky bar. Using high speed optical imaging, we are able to visualize the dynamic damage evolution in the composite as a function of the applied stress.

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  • Effect of Consolidation Pressure on the Transverse Compressive Strength of UHMWPE Composites at High Strain-rates

    JASON C. PARKER;K.T. RAMESH;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Direct Numerical Simulation of 3D Woven Textile Composites Subjected to Compressive Loading: A Multiscale Approach

    作者:DEEPAK K. PATEL;ANTHONY M. WAAS; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    Results for the compressive response of hybrid 3D woven textile composites (H3DWTCs) that consist of carbon, glass and kevlar fiber tows and a polymer matrix material are presented, using a combination of experiments and a multi-scale analysis of the full laboratory scale coupon for a class of H3DWTCs. The coupon model considers macro, meso and micro scale based modeling, where the notched gage area is explicitly modeled with fiber tows embedded in the matrix and the grip areas are homogenized at the macro scale. The meso scale fiber tows are considered homogenized entities of fibers and matrix, and are related to the constituents through an analytical micromechanics model. The experimental results suggest that carbon fiber compressive strength dictates the initiation of kink banding failure in carbon tows, while glass fiber tow compressive strength dictates the maximum load attainable. These experimental observations are seen to be captured by the 3-scale modeling strategy developed here and hence, seems to be a computationally efficient tool for the progressive damage and failure analysis of textile composites.

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  • Direct Numerical Simulation of 3D Woven Textile Composites Subjected to Compressive Loading: A Multiscale Approach

    DEEPAK K. PATEL;ANTHONY M. WAAS;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Quantitative Microscopic Investigation of Mode I Fracture Surfaces of Nanosilica-filled Epoxies

    作者:ANIRUDDH VASHISTH;TODD C. HENRY;CHARLES E. BAKIS; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    The addition of functionalized nanosilica (NS) particles to epoxy resins is known to improve certain mechanical properties such as modulus of elasticity and fracture toughness. In the current investigation, epoxies with and without NS reinforcement were investigated. Four NS concentrations were evaluated: 0, 15, 25 and a maximum wt% NS dependent on which of the two curing agents was used. The tensile modulus of elasticity and quasi-static Mode Ⅰ fracture toughness were measured and the Mode Ⅰ fracture surfaces were examined using a field emission scanning electron microscope for general imaging and a scanning laser confocal microscope for quantitative information on surface morphology. Fracture toughness, as measured by critical strain energy release rate (Gic), and fracture surface area increased monotonically with increased NS content in the epoxy cured with diethyltoluenediamine (DETDA). However, for the material cured at a higher temperature with 4-4’ diamino diphenyl sulfone (DDS), Gic and surface area reach their respective peaks at NS concentrations less than the maximum value. The primary morphological toughing mechanisms observed were particle pullout and crack deflection. The DDS cured system had higher surface area than DETDA system for any non-zero NS content, but less Gic. Analysis of the experimental results led to the conclusion that Gic of the DETDA was mostly explainable in the context of NS particle pullout, as both fracture surface area and Gic varied in rough proportion to NS content. In the DDS system, however, such proportional behavior was not observed and it is believed that competing mechanisms influence Gic at NS concentrations above 15 wt%.

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  • Quantitative Microscopic Investigation of Mode I Fracture Surfaces of Nanosilica-filled Epoxies

    ANIRUDDH VASHISTH;TODD C. HENRY;CHARLES E. BAKIS;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Fabrication of Cellulose Nanofiber/Glass Fiber-reinforced Composites and Their Bending Behavior Evaluation

    作者:YINGMEI XIE;HIROKI KURITA;RISA HONDA;KENICHI KATABIRA;FUMIO NARITA; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    It is required a joint technic with excellent mechanical properties to fabricate glass fiber reinforced plastic (GFRP) components. However, it is well-known that the mechanical jointing often causes the fracture of fiber reinforced plastics. It seems that the adhesive bonding is suitable to joint GFRPs, and it is necessary to develop an adhesive with outstanding mechanical properties. Recently, cellulose nanofibers (CNFs) have been obtained from plants by mechanical and chemical methods and it has been reported that CNFs have remarkable mechanical properties. In this study, we inserted epoxy resin with CNFs between GFRP and investigated its bending behavior, to estimate the capability of epoxy resin with CNFs as an adhesive for GFRPs. The flexural behavior and modulus of GFRP was similar regardless of the inserted part of epoxy resin with CNFs layer in GFRP. The flexural strength of GFRP was drastically increased (up to 600 MPa) by the insert of epoxy resin with CNFs of 5 or 10 wt.%, although that of GFRP was decreased by the insert of epoxy resin with CNFs of 25 wt.%. Therefore, it seems that the epoxy resin with CNFs is available as an adhesive for GFRP. However, it is required the observation of CNFs dispersion in epoxy resin to understand the strengthening mechanism of epoxy resin with CNFs.

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  • Fabrication of Cellulose Nanofiber/Glass Fiber-reinforced Composites and Their Bending Behavior Evaluation

    YINGMEI XIE;HIROKI KURITA;RISA HONDA;KENICHI KATABIRA;FUMIO NARITA;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Interesting Properties of 3D Warp Interlock Fabrics as Fibrous Reinforcement for Composite Materials

    作者:AXEL KECECI;FRANCOIS BOUSSU;DAMIEN SOULAT; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    3D fabrics tend to be more used as fibrous reinforcement into composite material due to their near-net-shape ability as well as their specific mechanical properties. Among these 3D structures, 3D warp interlock fabrics have been investigated in order to highlight their physical and mechanical properties. Several product parameters are needed to clearly define such a woven structure. In order to highlight the some product parameters influence, two different 3D warp interlock architectures with two different yarn’s raw material have been produced on the same weaving loom and tested. Significant mechanical behaviors have been observed in the weft direction compared to the warp direction, which tend to be stiffer due to less crimped yarns inside the woven structure. Additionally, it has been found that the shrinkage values of binding and stuffer warp yarns play an important mechanical behavior of 3D warp interlock fabrics during quasi-static tensile tests.

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  • Interesting Properties of 3D Warp Interlock Fabrics as Fibrous Reinforcement for Composite Materials

    AXEL KECECI;FRANCOIS BOUSSU;DAMIEN SOULAT;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • The Impact Resistance of Thermoplastic Fiber-metal Laminates Based on Glass and Basalt Fibers

    作者:FABRIZIO SARASINI;JACOPO TIRILLO;LUCA FERRANTE;CLAUDIA SERGI;PIETRO RUSSO;GIORGIO SIMEOLI;ANDREA CALZOLARI; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    In an attempt to reduce the elevated processing temperature and pressure required for a prolonged period for consolidation of components made from prepreg in conventional fiber metal laminates (FMLs), thermoplastic matrix FMLs, known as TFMLs, have recently been introduced. The present work is an experimental study on the low velocity impact response of a TFML based on thin layers of an aluminum alloy and a polypropylene (PP) matrix reinforced with basalt fibers. The response of the TFML based on basalt fibers under low velocity impact loading is evaluated, where the effect of varying the stacking configuration of the constituent materials is studied, with the results being compared to those offered by glass fiber/PP reinforced FMLs, basalt/epoxy reinforced FMLs and neat aluminum. The results show that basalt TFMLs behaved better than aluminum plates and glass TFMLs, especially for the energy level causing FC (first crack) due to a greater deformation ability of basalt fiber metal laminates.

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  • The Impact Resistance of Thermoplastic Fiber-metal Laminates Based on Glass and Basalt Fibers

    FABRIZIO SARASINI;JACOPO TIRILLO;LUCA FERRANTE;CLAUDIA SERGI;PIETRO RUSSO;GIORGIO SIMEOLI;ANDREA CALZOLARI;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Material Characterization and Finite Element Modeling for the Forming of Highly Oriented UHMWPE Thin Film and Unidirectional Cross-ply Composites

    作者:KARI WHITE;MICHAEL YEAGER;JAMES SHERWOOD;TRAVIS BOGETTI;JULIA CLINE; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    Thermoforming is a cost-effective, high-volume production process used for the manufacture of complex shaped thermoplastic composite parts. Finite element modeling of the process offers a cost-effective and time-saving tool to explore how changes in the ply stack-up orientations and processing conditions can impact part quality and throughput. A credible finite element model of the process requires a robust constitutive model of the material system and a comprehensive associated material characterization program to develop the set of material properties to go into that model. In this paper, some of the technical challenges associated with the charaterizaton of the in-plane shear mechanical behavior of two UHMWPE compsosite formats; a unidirectional fiber/matrix cross-ply (Dyneema® HB210) and a highly-oriented extruded film (DuPontTM TensylonTM HSBD 30A) and the subsequent finite element modeling of the shear response are explored. Picture frame shear testing of each material system is conducted to examine the mechanical behavior at room temperature and a processing temperature of 100℃. Trilinear and ploynomial empirical fits of the evolution of the in-plane shear stiffness as a function of the state of in-plane shear are derived from these experimental data. The curves are then used as material inputs for two material models in LS-DYNA, i.e. the built-in *MAT214 (*MAT_DRY_FABRIC) and *MAT41 (user-defined material model), respectively. The two material models are first used to investigate their respective abilities to replicate the material characterization shear-frame tests for Dyneema® HB210 and TensylonTM HSBD 30A and subsequently to model an in-plane shear test, which is a variation of the bias-extension test. Both material models correlate very well with the shear-frame test data for the two material systems and for the in-plane shear test of Dyneema® HB210. However, both material models underpredict the load deformation response for TensylonTM HSBD 30A. Future work is to understand what enhancements need to be added to the material models such that the in-plane shear response of TensylonTM HSBD 30A is better predicted by the models.

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  • Material Characterization and Finite Element Modeling for the Forming of Highly Oriented UHMWPE Thin Film and Unidirectional Cross-ply Composites

    KARI WHITE;MICHAEL YEAGER;JAMES SHERWOOD;TRAVIS BOGETTI;JULIA CLINE;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Micromechanical Progressive Failure Analysis of Composite Materials Using Continuum Decohesive Finite Element

    作者:SHIYAO LIN;ANTHONY M. WAAS; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    An efficient framework for microscopic progressive failure analysis of fiberreinforced composite is established using the continuum decohesive finite element (CDFE) method. CDFE is a novel finite element technique connecting continuum and cohesive crack modeling seamlessly. In CDFE, the transition from a continuum to non-continuum (cracked solid) is modeled by physically introducing pairs of crack dummy nodes. A static condensation algorithm is applied to solve for and preserve the crack separation information on the crack dummy nodes to facilitate the implementation of CDFE into general-purpose finite element solvers. In this paper, CDFE is applied to micromechanical progressive failure analyses on a representative volume element (RVE) of composite materials with randomly packed fibers. No crack path is predefined and the maximum principal stress criterion (MPSC) is used to determine the crack orientation and initiation. According to CDFE results, multiple microscopic cracks initiate at different locations and coalesce into a macroscopic transverse crack. By comparison with existing FE results and high-fidelity generalized method of cells (HFGMC) results, the CDFE framework proves to be accurate and efficient.

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  • Micromechanical Progressive Failure Analysis of Composite Materials Using Continuum Decohesive Finite Element

    SHIYAO LIN;ANTHONY M. WAAS;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Modeling and Simulation of Carbon Composite Blast Behavior

    作者:CHIAN-FONG YEN;ROBERT KASTE;CHARLES CHIH-TSAI CHEN;NELSON CAREY; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    The design of new generation aircraft is driven by the vastly increased fuel cost and the resultant imperative for greater fuel efficiency. Carbon fiber composites have been used in aircraft structures to lower weight due to their superior stiffness and strength-to-weight properties. However, carbon composite material behavior under dynamic ballistic and blast loading conditions is relatively unknown. For aviation safety consideration, a computational constitutive model has been used to characterize the progressive failure behavior of carbon laminated composite plates subjected to ballistic and blast loading conditions. Using a meso-mechanics approach, a laminated composite is represented by a selected number of representative unidirectional layers with proper layup configurations. The damage progression in a unidirectional layer is assumed to be governed by a set of strain-rate dependent layer progressive failure criteria using the continuum damage mechanics approach. The composite failure model has been successfully implemented within LS-DYNA as a user-defined material subroutine. In this study, a series of experimental, close-in shock-hole blast tests on carbon composite panels, were simulated using the LS-DYNA-ALE method integrated with the ARL progressive failure composite model, which include strain rate effects on damage and fracture. The computational constitutive model has been validated to characterize the progressive failure behavior in carbon laminates subjected to close-in blast loading conditions with reasonable accuracy. The availability of this modeling tool will greatly facilitate the development of carbon composite structures with enhanced ballistic and blast survivability.

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  • Modeling and Simulation of Carbon Composite Blast Behavior

    CHIAN-FONG YEN;ROBERT KASTE;CHARLES CHIH-TSAI CHEN;NELSON CAREY;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Numerical Simulation of Failure Behavior Under Impact Loading for Cylindrical Carbon Fiber Reinforced Polymer

    作者:YUSUKE SAWAMURA;YUTA YAMAZAKI;JUN KOYANAGI;SATORU YONEYAMA; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    This study presents a prediction for the dynamic failure behavior of the carbon fiber reinforced polymer (CFRP) under impact loading. In the experiment, the split Hopkinson pressure bar (SHPB) test was conducted by using two types of cylindrical CFRP specimens. The commercial finite element analysis (FEA) software Abaqus was used for the analysis. In this study, we considered two types of failure mechanisms, a problem that mainly involves matrix-dominated failure and does not involve fiber breakage and a problem that involves fiber-dominated failure. To predict the matrix-dominated failure, we adopted multi-scale analysis, which is a method that can carry out analysis at different scales. We considered the damage initiation criterion based on continuum damage mechanics (CDM). This damage initiation criterion was based on the Christensen failure criterion. We simulated interfacial failure by using cohesive zone modeling (CZM), which considers failure conditions in mixed mode. In micro-scale analysis, a two-dimensional periodic unit cell (PUC) was used and we considered CDM and CZM. Macro-scale analysis was conducted in the same way as in the SHPB experiments. To predict the fiber-dominated failure, simulation was carried out using the Hashin damage theory. Parameters used in macro-scale analysis were obtained from micro-scale analysis. Macro-scale analysis is currently conducted.

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  • Numerical Simulation of Failure Behavior Under Impact Loading for Cylindrical Carbon Fiber Reinforced Polymer

    YUSUKE SAWAMURA;YUTA YAMAZAKI;JUN KOYANAGI;SATORU YONEYAMA;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Reliability-based Approach for Sandwich Composite Structural Applications

    作者:SADRA EMAMI;ELIAS TOUBIA;KELLIE SCHNEIDER; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    Composite sandwich structures have many advantages in engineering design, due to their light weight and resistance to corrosion and in-service environmental conditions. Recent interest in such composite structures has increased in structural applications. Liability concerns prevent most structural engineers from considering this material, specifically, when the basis of the technical design data and long-term durability behavior are still uncertain. For this purpose, several sandwich composite samples (Balsa and PVC foam) were molded and subjected to severe weathering and environmental conditions. Experimental tests to predict the core shear strength, compression and moduli of the sandwich structures were performed on 30 samples. The Load and Resistance Factor Design (LRFD) method was employed and the resistance factors of the core shear and compression strengths were developed. This work advances the current state of the art by assisting engineers to quantify the reliability of their design and increase the utilization of composites as a reliable material for structures. The results of this research will ultimately lead to a probabilistic analysis model as well as act as a reference to guide those applying this technology.

    关键字:

  • Reliability-based Approach for Sandwich Composite Structural Applications

    SADRA EMAMI;ELIAS TOUBIA;KELLIE SCHNEIDER;

    American Society for Composites technical conference;American Society for Composites

    2018年

  • Long-term Stress Rupture Limitations of Unidirectional High Strain Composites in Bending

    作者:KAMRON MEDINA;T.J. ROSE;WILL FRANCIS; 会议名称:American Society for Composites technical conference;American Society for Composites 2018年

    The efficiency of any deployable structure for aerospace applications is directly correlated to the mass/stiffness ratio and the volume compaction ratio. While High Strain Composite (HSC) materials have a large mass/stiffness ratio the volume compaction ratio is a direct function of the maximum safe stowage strain-limit of the HSC. Previous works have shown that HSC materials are capable of achieving surface strains in excess of the tensile and compressive allowable strains for the constituent fiber. However, it has also been noted that large surface strains exhibit a time-dependent failure behavior. The purpose of this paper was to begin an investigation of the stressstrain- time dependent behavior of an IM7 unidirectional TP-HSC utilizing a novel adaptation of the Column Bend Test method for Long-Term testing (CBT-LT). Ultimate failure curvature testing was conducted on the IM7 laminate to determine long-term test curvature levels corresponding to 80%, 85%, and 90% of the ultimate value. Out of the ten stress rupture/relaxation tests conducted, five were observed to reach stress rupture within six-months of accelerated effective time. All five of the ruptured samples were held at surface strains in excess of 1.7%, corresponding to 89.5% of the reported ultimate tensile failure strain of an IM7 fiber and 91.8% of the ultimate failure surface strain of the IM7 laminate determined in this study. While the initial stress relaxation/rupture trends observed using the CBT-LT method is promising, future work is needed to improve the fidelity of the test method.

    关键字:

  • Long-term Stress Rupture Limitations of Unidirectional High Strain Composites in Bending

    KAMRON MEDINA;T.J. ROSE;WILL FRANCIS;

    American Society for Composites technical conference;American Society for Composites

    2018年

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