Effective Transverse Electrical Permittivities of Plain Weave, Twill Weave and Satin Fabric Composites

1995 ◽  
Vol 411 ◽  
Author(s):  
T.-W. Chou ◽  
Q-G. Ning
Keyword(s):  
Volume Fraction ◽  
Effective Properties ◽  
Dielectric Behavior ◽  
Analytical Prediction ◽  
Fiber Volume ◽  
Plain Weave ◽  
Fabric Composite ◽  
Fabric Composites ◽  
Electrical Permittivity ◽  
Twill Weave

ABSTRACTThis paper reports the analytical prediction of effective transverse electrical permittivities of plain weave, twill weave, 4-harness irregular satin, as well as 5-harness and 8-harness satin fabric composites with lossy constituents. Analytical solutions of the effective properties are presented. Numerical examples are given to illustrate the effects of fiber volume fraction and fabric architecture on the composite effective transverse dielectric behavior. Key words: electrical permittivity, plain weave, twill weave, satin weave, fabric composite, analytical solution.

Measurement and Prediction of Effective Thermal Conductivity for Woven Fabric Composites

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1808-1813 ◽  
Author(s):  
Nam Seo Goo ◽  
Kyeongsik Woo
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Woven Fabric ◽  
Fiber Volume ◽  
Plain Weave ◽  
Woven Fabric Composites ◽  
Weave Fabric ◽  
Experimental Apparatus ◽  
Fabric Composites ◽  
Thermal Conductivities

The current paper deals with the measurement and prediction of thermal conductivities for plain weave fabric composites. An experimental apparatus was setup to measure the temperature gradients from which the thermal conductivities were obtained. The thermal conductivities were also calculated using finite element analyses for plain weave unit cell models and then compared with experimental results. In addition, the effect of a phase shift and the fiber volume fraction in the tow on the thermal conductivities was addressed.

Effect of Nesting of Fiber Bundles on Micro Fracture of Laminated Woven Fabric Composite

2002 ◽  
Author(s):  
Toshiko Osada ◽  
Asami Nakai ◽  
Hiroyuki Hamada
Keyword(s):  
Volume Fraction ◽  
Woven Fabric ◽  
Fiber Bundles ◽  
Fiber Volume ◽  
Woven Fabric Composites ◽  
Number Of Layers ◽  
Fabric Composite ◽  
Knee Point ◽  
Fabric Composites ◽  
Layer Increase

In laminated woven fabric composites, fiber bundles do not pack tightly because there are resin rich regions caused by crimp of fiber bundles. The fiber bundles in one layer are often fitted into the neighboring layer, which is called nesting. In this study, the effect of nesting by laminating on mechanical properties and micro fracture behavior of composites was investigated. Tensile testing of woven fabric composites with different number of layers and observation using optical microscopy were performed. With the increase of number of layers, nesting is more likely to occur, resulting in a decrease in thickness per layer increase in fiber volume fraction. This also lead to an increase in modulus and strength but a decrease in knee point stress. The locations at which cracks occurred were different in specimens with and without nesting.

Thermo-Mechanical Modeling of 3D Woven Fabric Composites Using Two-Step Homogenization Approach

2019 ◽  
Author(s):  
Nagappa Siddgonde ◽  
Anup Ghosh
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Woven Fabric ◽  
Fiber Volume ◽  
Woven Fabric Composites ◽  
Fabric Composite ◽  
Fabric Composites ◽  
Matrix Properties ◽  
Homogenization Approach ◽  
3D Fea

Abstract A 3D finite element based Representative Volume Element (RVE) model has been developed to predict the thermo-mechanical properties of 3D orthogonal interlock woven fabric composites (OIWFC) and angle interlock woven fabric composite (AIWFC) using a two-step homogenization approach. The first step homogenization, micro-homogenization, deals with resin infiltration effect of yarn as a unidirectional continuous fiber with an assumption of 80 percent of fiber volume fraction based on initial fiber and matrix properties. The second step, meso-homogenization, predicts effective thermo-mechanical properties of 3D woven fabric composites based on effective yarn and matrix properties. The RVE analysis has been performed using 3D FEA method with periodic boundary conditions (PBCs). Further, a void study has been performed considering the influences of void on thermo-mechanical properties of the 3D woven fabric composite. It is noted that the influence of void contents plays a significant role in predicting the thermo-mechanical properties of the 3D WFC. The thermo-mechanical properties gradually decrease with an increase of void contents. Studies have been carried out considering the same fiber volume fractions in both 3D WFC models. An AIWFC model predicts higher values of thermo-mechanical constants than OIWFC model.

Experimental investigation of the tensile and bending behavior of multi-axial warp-knitted fabric composites

2016 ◽  
Vol 88 (3) ◽  
pp. 333-344 ◽  
Author(s):  
Xiaoping Gao ◽  
Danxi Li ◽  
Wei Wu ◽  
Si Chen
Keyword(s):  
Volume Fraction ◽  
Orientation Distribution ◽  
Knitted Fabric ◽  
Fiber Volume ◽  
Molding Method ◽  
Fabric Composite ◽  
Fabric Composites ◽  
Static Tensile ◽  
Bending Behavior ◽  
Warp Knitted Fabric

An experimental study was carried out on the tensile and bending behavior of multi-axial warp-knitted fabric composites. Five specimens reinforced with multi-axial warp-knitted fabric/epoxy were manufactured by a vacuum-assisted resin transfer molding method. Quasi-static tensile and three-point bending tests were carried out in a number of orientations relative to the stitching direction: quadriaxial, triaxial, biaxial (±45° and 0/90°) and unidirectional. The results of the tests revealed that the quadriaxial and biaxial (±45°) samples showed quasi-isotropic behavior, whereas the other laminates showed anisotropic behavior. The influence of fiber volume fraction and the orientation distribution of the constituent material on the tensile and bending behavior were also analyzed. The relationships between the stress and strain and the tensile and bending behavior of different multi-axial warp-knitted fabric composite were obtained by polynomial fitting.

An Analytical and Experimental Study of Strength and Failure Behavior of Plain Weave Composites

1998 ◽  
Vol 32 (1) ◽  
pp. 2-30 ◽  
Author(s):  
Makoto Ito ◽  
Tsu-Wei Chou
Keyword(s):  
Volume Fraction ◽  
Random Phase ◽  
Three Dimensional ◽  
Tensile Tests ◽  
Packing Fraction ◽  
Failure Behavior ◽  
Fiber Volume ◽  
Laminate Composites ◽  
Plain Weave ◽  
Geometrical Characteristics

This paper analyzes the strengxth and failure behavior of plain weave composites. First, the geometrical characteristics of yarn shape, laminate stacking configuration, fiber volume fraction, and yarn packing fraction are investigated using three-dimensional geometrical models. Based on the geometrical characteristics, iso-strain approach is developed to predict elastic properties, stress distributions, and strengths under tensile loading. The laminate stacking configuration and fabric waviness ratio have significant influence on the composite failure behavior. Specimens of iso-phase, out-of-phase and random-phase laminate composites are prepared. The mathematical models developed are evaluated by microscopic observation and tensile tests.

Automated RVE computations for evaluation of microdamage initiation in structural stitched non-crimp fabric composites

2020 ◽  
Vol 54 (30) ◽  
pp. 4751-4771
Author(s):  
Gerrit Pierreux ◽  
Danny Van Hemelrijck ◽  
Thierry J Massart
Keyword(s):  
Cross Sections ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Direction ◽  
Fiber Volume ◽  
Damage Initiation ◽  
Processing Step ◽  
Fabric Composites ◽  
Out Of Plane ◽  
Generate Unit

This contribution presents an approach to generate unit-cell models of structural stitched non-crimp fabric composites. Resin-rich regions and out-of-plane undulations caused by the stitching yarn are represented by initially straight discretised lines, while the stitching yarn is represented initially by a single discretised line which can be transformed into a multi-line configuration to model stitch cross-section variations. The discretised lines are shaped by geometrical operations with a contact treatment and boundary conditions being used to account, respectively, for line interactions and to control the shape of the bottom and top surfaces of each lamina respectively. A fiber-reinforced distorted zone with local variations in fiber volume fraction and fiber direction is modelled in cross-sections of the lamina in a post-processing step. Models for different stacking sequences and stitching parameters are then automatically generated and subsequently being in the stiffness calculation and damage initiation assessment using finite element based mechanical simulations.

scholarly journals An Energy-Based Model of Longitudinal Splitting in Unidirectional Fiber-Reinforced Composites

1999 ◽  
Vol 67 (3) ◽  
pp. 437-443 ◽  
Author(s):  
K. Oguni ◽  
G. Ravichandran
Keyword(s):  
Volume Fraction ◽  
Effective Properties ◽  
Confining Pressure ◽  
Fiber Reinforced Composites ◽  
Fiber Direction ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Unidirectional Fiber ◽  
Longitudinal Splitting

Unidirectional fiber-reinforced composites are often observed to fail in a longitudinal splitting mode in the fiber direction under far-field compressive loading with weak lateral confinement. An energy-based model is developed based on the principle of minimum potential energy and the evaluation of effective properties to obtain an analytical approximation to the critical stress for longitudinal splitting. The analytic estimate for the compressive strength is used to illustrate its dependence on material properties, surface energy, fiber volume fraction, fiber diameter, and lateral confining pressure. The predictions of the model show good agreement with available experimental data. [S0021-8936(00)02003-1]

Micromechanical Analysis of Heterogeneous Composites using Hybrid Trefftz FEM and Hybrid Fundamental Solution Based FEM

2013 ◽  
Vol 29 (4) ◽  
pp. 661-674 ◽  
Author(s):  
C. Y. Cao ◽  
Q.-H. Qin ◽  
A. B. Yu
Keyword(s):  
Fundamental Solution ◽  
Volume Fraction ◽  
Effective Properties ◽  
Multiscale Simulation ◽  
Homogenization Method ◽  
Micromechanical Modeling ◽  
Future Application ◽  
Fiber Volume ◽  
Mesh Density ◽  
Properties Of Composites

ABSTRACTIn this paper, a new algorithm is developed based on the homogenization method integrating with the newly developed Hybrid Treffe FEM (HT-FEM) and Hybrid Fundamental Solution based FEM (HFS-FEM). The algorithm can be used to evaluate effective elastic properties of heterogeneous composites. The representative volume element (RVE) of fiber reinforced composites with periodic boundary conditions is introduced and used in our numerical analysis. The proposed algorithm is assessed through two numerical examples with different mesh density and element geometry and used to investigate the effect of fiber volume fraction, fiber shape and configuration on the effective properties of composites. It is found that the proposed algorithm is insensitive to element geometry and mesh density compared with the traditional FEM (e.g. ABAQUS). The numerical results indicate that the HT-FEM and HFS-FEM are promising in micromechanical modeling of heterogeneous materials containing inclusions of various shapes and distributions. They are potential to be used for future application in multiscale simulation.

scholarly journals Fabrication of High Quality, Large Wet Lay-Up/Vacuum Bag Laminates by Sliding a Magnetic Tool

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 992 ◽  
Author(s):  
Marli Sussmann ◽  
Mehrad Amirkhosravi ◽  
Maya Pishvar ◽  
M. Altan
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Optimal Number ◽  
Large Area ◽  
Fiber Volume ◽  
High Quality ◽  
Plain Weave ◽  
Consolidation Pressure ◽  
Novel Method ◽  
Number Of Passes

This study presents a novel method to fabricate high-quality, large composite parts which can be used in a wet lay-up/vacuum bag (WLVB) process. The new method utilizes a commercial lifting magnet, which is commonly used for transporting ferrous plates, to apply a magnetic consolidation pressure on the WLVB composite lay-up. The pressure is applied on a large area of the laminate by slowly sliding the magnet over the vacuum bag surface, which leads to an improved laminate quality. When further improvement is desirable, multiple passes of the magnet can be performed, where each pass successively compacts the lay-up. To explore the feasibility of implementing this technique, random mat and plain weave glass/epoxy laminates were fabricated, and their properties compared to conventional WLVB laminates. The effects of the number of moving passes of the lifting magnet on the laminate microstructure and properties are also investigated. As a result of multiple passes, the fiber volume fraction in random mat and plain weave laminates increases to 34% and 53%, representing 80% and 16% improvements, respectively. In addition, the void volume fraction reduces almost by 60% to a very low level of 0.7% and 1.1%, respectively. Consequently, the flexural properties considerably enhance by 20–81%, which demonstrates the potential of the proposed method to produce WLVB parts with substantially higher quality. It is also shown that there exists an optimal number of passes, depending on the fabric type where additional passes induce new voids as a result of excessive resin removal.

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