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.

Parametric Generation of Random Distribution of Fibers in Long-Fiber Reinforced Composites and Micromechanical FE Analysis

2010 ◽  
Vol 452-453 ◽  
pp. 117-120
Author(s):  
Zhen Qing Wang ◽  
Xiao Qiang Wang ◽  
Ji Feng Zhang ◽  
Song Zhou
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Fiber Volume Fraction ◽  
Random Distribution ◽  
Volume Fraction ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Parametric Generation ◽  
High Fiber ◽  
Damage Initiation

A method for the parametric generation of the transversal cross-section microstructure model of unidirectional long-fiber reinforced composite (LFRC) is presented in this paper. Meanwhile, both the random distribution of the fibers and high fiber volume fraction are considered in the algorithm. The fiber distribution in the cross-section is generated through random movements of the fibers from their initial regular square arrangement. Furthermore, cohesive zone element is introduced into modeling the interphase between the fiber and the matrix. All these processes are carried out by the secondary development of the finite element codes (ABAQUS) via Python language programming. Based on the model generated, micromechanical finite element analysis (FEA) is performed to predict the damage initiation and subsequent evolution of the composites. The results show that this technique is capable of capturing the random distribution nature of these composites even for high fiber volume fraction. Moreover, the results prove that a good agreement with the experimental results is found.

Effect of layer shift on the out-of-plane permeability of 0°/90° noncrimp fabrics

2014 ◽  
Vol 33 (22) ◽  
pp. 2073-2094 ◽  
Author(s):  
Liangchao Fang ◽  
Jianjun Jiang ◽  
Junbiao Wang ◽  
Chao Deng ◽  
Dejia Li ◽  
...  
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Dominant Role ◽  
Fiber Volume ◽  
Transfer Molding ◽  
Local Permeability ◽  
Out Of Plane ◽  
Unit Cells ◽  
Flow Through ◽  
Key Parameter

Layer shift has a great effect on the permeability which is a key parameter in resin transfer molding. In this paper, nine different unit cells were modeled based on the range of layer shift and decomposed into zones of characteristic yarn arrangement, respectively. For each unit cell, a set of equations was derived allowing description of the local permeability of each zone as a function of geometrical yarn parameters. The overall permeability was then modeled as a mixture of permeabilities of different zones with the electrical resistance analogy. Excellent agreement was found between predictions and experiment. Both results indicated that the channel flow had a dominant role in the whole flow through the fabrics. And the permeability values reached maximum when the empty regions were interconnected between upper and lower layers. In addition, the effect of fiber volume fraction on the differences of two extreme cases was also investigated.

scholarly journals Pengaruh Penambahan Serat Batang Pisang Ketip dan Filler Dedak Padi Terhadap Density, Kekuatan Bending dan Tarik Kompositcore, Sandwich dengan Skin Plywood

MECHANICAL ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 1
Author(s):  
Salman Salman ◽  
Ahmad Fadly
Keyword(s):  
Tensile Strength ◽  
Fiber Volume Fraction ◽  
Bending Strength ◽  
Volume Fraction ◽  
Sandwich Composite ◽  
Fiber Direction ◽  
Fiber Volume ◽  
Banana Fiber ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite

Fiber-reinforced composite core banana stems with additional filler of husk powder is another way to obtain the expected mechanical behavior of the composite. The aim of this study was to analyze the effect of fiber volume fraction content to density, bending strength and tensile strength of sandwich composite.   Preparation of composite was done by hand lay-up method. Composite material used by banana ketip  fiber and addition of husk powder with variation of fiber volume fraction were 7, 10, and 13 % where husk was constant at 5% with random fiber direction. Tests were conducted by referring to the density est standard (ASTM C 271), bending est (ASTM C 393) and tensile test (ASTM D3039).  The result showed that the greater volume fraction of banana fiber, the lower the density value and the lower the bending strength. Whereas the tensile strength tended to increase as the volume fraction was higher.

Permeability models of 0°/45° alternating multilayer fabrics considering the effect of layer shift

2016 ◽  
Vol 36 (3) ◽  
pp. 163-175 ◽  
Author(s):  
Shuo Feng
Keyword(s):  
Mathematical Models ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Unit Cell ◽  
Analytical Models ◽  
Experimental Measurements ◽  
Fiber Volume ◽  
Local Permeability ◽  
Out Of Plane

In this paper, the effect of layer shifting on out-of-permeability of 0°/45° alternating multilayer fabrics was studied. Three mathematical models with three extreme structures were developed to predict the out-of-plane permeability, respectively. By segmenting the unit cell into several different zones according to characteristic yarn arrangement, the global permeability was modeled by using a rule of mixture of local permeability. The influences of local permeability of each zone on the global value of unit cell were carefully researched. In addition, experimental measurements of the permeability were carried out to validate the analytical models. And the differences of the results of three extreme structures with respect to fiber volume fraction were also investigated.

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.

scholarly journals Novel cattail fiber composites: converting waste biomass into reinforcement for composites

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Md. Shadhin ◽  
Mashiur Rahman ◽  
Raghavan Jayaraman ◽  
Danny Mann
Keyword(s):  
Fiber Volume Fraction ◽  
Polyester Resin ◽  
Volume Fraction ◽  
Natural Fibers ◽  
Areal Density ◽  
Fiber Composites ◽  
Waste Biomass ◽  
Fiber Volume ◽  
Resin Impregnation ◽  
Out Of Plane

AbstractVacuum-assisted resin transfer molding (VARTM), used in manufacturing medium to large-sized composites for transportation industries, requires non-woven mats. While non-woven glass mats used in these applications are optimized for resin impregnation and properties, such optimized mats for natural fibers are not available. In the current research, cattail fibers were extracted from plants (18–30% yield) using alkali retting and non-woven cattail fiber mat was manufactured. The extracted fibers exhibited a normal distribution in diameter (davg. = 32.1 µm); the modulus and strength varied inversely with diameter, and their average values were 19.1 GPa and 172.3 MPa, respectively. The cattail fiber composites were manufactured using non-woven mats, Stypol polyester resin, VARTM pressure (101 kPa) and compression molding pressures (260 and 560 kPa) and tested. Out-of-plane permeability changed with the fiber volume fraction (Vf) of the mats, which was influenced by areal density, thickness, and fiber packing in the mat. The cattail fibers reinforced the Stypol resin significantly. The modulus and the strength increased with consolidation pressures due to the increase in Vf, with maximum values of 7.4 GPa and 48 MPa, respectively, demonstrating the utility of cattail fibers from waste biomass as reinforcements.

scholarly journals Continuous Fiber-Reinforced Aramid/PETG 3D-Printed Composites with High Fiber Loading through Fused Filament Fabrication

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 298
Author(s):  
Sander Rijckaert ◽  
Lode Daelemans ◽  
Ludwig Cardon ◽  
Matthieu Boone ◽  
Wim Van Paepegem ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Composite Materials ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Low Cost ◽  
Fiber Direction ◽  
Continuous Fiber ◽  
Fiber Volume ◽  
Fiber Loading ◽  
3D Printed

Recent development in the field of additive manufacturing, also known as three-dimensional (3D) printing, has allowed for the incorporation of continuous fiber reinforcement into 3D-printed polymer parts. These fiber reinforcements allow for the improvement of the mechanical properties, but compared to traditionally produced composite materials, the fiber volume fraction often remains low. This study aims to evaluate the in-nozzle impregnation of continuous aramid fiber reinforcement with glycol-modified polyethylene terephthalate (PETG) using a modified, low-cost, tabletop 3D printer. We analyze how dimensional printing parameters such as layer height and line width affect the fiber volume fraction and fiber dispersion in printed composites. By varying these parameters, unidirectional specimens are printed that have an inner structure going from an array-like to a continuous layered-like structure with fiber loading between 20 and 45 vol%. The inner structure was analyzed by optical microscopy and Computed Tomography (µCT), achieving new insights into the structural composition of printed composites. The printed composites show good fiber alignment and the tensile modulus in the fiber direction increased from 2.2 GPa (non-reinforced) to 33 GPa (45 vol%), while the flexural modulus in the fiber direction increased from 1.6 GPa (non-reinforced) to 27 GPa (45 vol%). The continuous 3D reinforced specimens have quality and properties in the range of traditional composite materials produced by hand lay-up techniques, far exceeding the performance of typical bulk 3D-printed polymers. Hence, this technique has potential for the low-cost additive manufacturing of small, intricate parts with substantial mechanical performance, or parts of which only a small number is needed.

scholarly journals Novel Cattail Fiber Composites - Converting Waste Biomass into Reinforcement for Composites

2021 ◽  
Author(s):  
Md Shadhin ◽  
Mashiur Rahman ◽  
Raghavan Jayaraman ◽  
Danny Mann
Keyword(s):  
Fiber Volume Fraction ◽  
Polyester Resin ◽  
Volume Fraction ◽  
Natural Fibers ◽  
Areal Density ◽  
Fiber Composites ◽  
Waste Biomass ◽  
Fiber Volume ◽  
Resin Impregnation ◽  
Out Of Plane

Abstract Vacuum Assisted Resin Transfer Molding (VARTM), used to manufacture medium to large sized composites for transportation industries, require non-woven mats. While non-woven glass mats used in these applications are optimized for resin impregnation and properties, such optimized mats for natural fibers are not available. In the current research, cattail fibers were extracted from plants (18–30% yield) using alkali retting and nonwoven cattail fiber mat was manufactured. The extracted fibers exhibited a normal distribution in diameter (davg. = 32.1 µm) and the modulus and strength decreased with increase in diameter with average values of 19.1 GPa and 172.3 MPa, respectively. The cattail fiber composites were manufactured using non-woven mats, Stypol polyester resin, and VARTM (101 kPa) and compression molding pressures (260 and 560 kPa) and tested. Out-of-plane permeability changed with Vf of mats, which was influenced by areal density, thickness, and fiber packing in the mat. The cattail fibers reinforced the stypol resin significantly. The modulus and the strength increased with consolidation pressures due to increase in fiber volume fraction (Vf), with maximum values of 7.4 GPa and 48 MPa, demonstrating the utility of Cattail fibers from waste biomass as reinforcements.

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