Predictions of Elastic Properties of Multi-Axial Warp Knitted Fabric Composites

2004 ◽  
Vol 261-263 ◽  
pp. 1499-1504 ◽  
Author(s):  
Heoung Jae Chun ◽  
K.S. Ryu ◽  
Joon Hyung Byun
Keyword(s):  
Elastic Properties ◽  
Averaging Method ◽  
Three Dimensional ◽  
Design Parameters ◽  
Fabric Composite ◽  
Fabric Composites ◽  
Out Of Plane ◽  
Experimental Values ◽  
Warp Knitted Fabric ◽  
Good Agreement

An analytical model was proposed to predict the elastic properties of multi-axial warp knitted (MWK) fabric composites for three-dimensional structures. The characteristics of MWK fabric composites are the assemblage of multilayers of rovings in the warp, weft and bias directions for in-plane reinforcement and out-of-plane stitches by knitting rovings to provide through-the- thickness reinforcement. For analysis, a representative volume of the MWK fabric composite was identified. The geometric limitations, effects of stitch fibers and design parameters of MWK composites are considered in the model. Then, the elastic properties of MWK fabric composites are predicted by using an averaging method. The experiments are also conducted on the MWK fabric composites to compare the predicted results with the experimental results for the verification of suggested model. The predicted elastic properties are in reasonably good agreement with the experimental values. Finally the effects of design parameters of the MWK fabric composites are discussed.

ELASTIC PROPERTY PREDICTION OF THE STITCHED MULTI-AXIAL WARP KNIT FABRIC COMPOSITES

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4022-4027 ◽  
Author(s):  
HEOUNG-JAE CHUN ◽  
HYUNG-WOO KIM ◽  
JOON-HYUNG BYUN
Keyword(s):  
Composite Materials ◽  
Elastic Properties ◽  
Cross Sections ◽  
Averaging Method ◽  
Geometric Parameters ◽  
Suggested Model ◽  
Fabric Composites ◽  
Out Of Plane ◽  
Experimental Values ◽  
Good Agreement

In order to improve the resistances to delamination, damage tolerance, some in-plane and out-of-plane properties of composite materials, a through-thickness reinforcement must be provided. This through-thickness reinforcement is achieved by stitching multi-axial warp knit (MWK) fabrics used as preforms for the fabrication of composite materials. The MWK fabrics are constructed with layers of insertion fiber bundles in the warp, weft and bias directions. In order to correlate the microstructure of a preform with the elastic properties of stitched MWK composite, the analytical model for stitched MKW composite is developed. The overall geometry and geometric parameters of a representative volume are determined from the photomicrographs of cross sections of the fabricated composite specimens. The various elastic properties of MWK fabric composites are predicted as functions of various geometric parameters using an averaging method. The experimental results are compared with the predicted results in order to validate the suggested model. It is found that the predicted elastic properties are in reasonably good agreement with the experimental values.

Elastic Behaviors of Stitched Multi-Axial Warp Knit Fabric Composites

2006 ◽  
Vol 306-308 ◽  
pp. 817-822 ◽  
Author(s):  
Heoung Jae Chun ◽  
H.W. Kim ◽  
Joon Hyung Byun
Keyword(s):  
Composite Materials ◽  
Elastic Properties ◽  
Structural Integrity ◽  
Experimental Results ◽  
Fiber Volume ◽  
Representative Volume ◽  
Fabric Composites ◽  
Out Of Plane ◽  
Stress States ◽  
Warp Knitted Fabric

The purposes of stitching multi-axial warp knitted fabric preform prior to the fabrication of the composite materials by resin-transfer molding technique are to improve the resistance to delamination and to increase the out-of-plane properties of the composite materials for structural integrity. The influence of the through-the-thickness stitching on the elastic properties and behaviors of the multi-axial warp knit fabric composites is studied. An analytical model based on the representative volume is proposed to predict the elastic properties of the stitched multi-axial warp knit fabric composite materials. The fiber volume ratios determined by geometric parameters set by the representative volume and elastic behaviors of the in-situ constituent materials are used for the predictions. The crucial step in the analysis is to correlate the averaged stress states in the constituents by adopting bridging matrix. The predicted results are compared with the experimental results. It is found that the predicted results are in reasonably good agreement with the experimental results.

Effect of design parameters on the cushioning property of cellular fabric composites

2018 ◽  
Vol 89 (18) ◽  
pp. 3692-3699
Author(s):  
Chunhong Zhu ◽  
Jian Shi ◽  
Kasumi Hayashi ◽  
Hideaki Morikawa ◽  
Akio Sakaguchi ◽  
...  
Keyword(s):  
Design Method ◽  
Three Dimensional ◽  
Hollow Structure ◽  
Woven Fabric ◽  
Design Parameters ◽  
Polyurethane Elastomer ◽  
Fabric Structure ◽  
Fabric Composite ◽  
Fabric Composites ◽  
Compression Resistance

In this study, a new design method for a three-dimensional hollow structure woven fabric was proposed and the effect of cellular size on the cushioning property of the fabric-reinforced polyurethane elastomer composite was investigated. The fabric structure was analyzed from a cross-section view and the theoretical equations for the warp and weft yarns were proposed, using the fabric layer and cellular size as parameters. Nine kinds of fabrics with different layers and cellular size were fabricated with a Jacquard loom and reinforced with polyurethane elastomer to yield fabric composites. Then the effect of cellular size on the cushioning property of the fabric composites was discussed. The results showed that upon increasing the cellular size, the cellular fabric composite exhibited lower compression resistance. Moreover, the stress at a strain of 65% and the energy absorbed in the loading process were increased with decreasing cellular size. Moreover, the compression resilience was also changed with the cellular size. It can be concluded that the cellular size had an important effect on the cushioning property of the fabric composite, which can be considered as a design parameter for cushion material based on its usages.

scholarly journals Deep Drawing of Plain Weft-Knitted Fabric Composites: Part 1.: Cup Height Analysis

1999 ◽  
Vol 8 (6) ◽  
pp. 096369359900800 ◽  
Author(s):  
T.C. Lim ◽  
S. Ramakrishna ◽  
H.M. Shang
Keyword(s):  
Deep Drawing ◽  
Shell Height ◽  
Knitted Fabric ◽  
Fabric Structure ◽  
Weft Knitted Fabric ◽  
Fabric Composite ◽  
Fabric Composites ◽  
Good Agreement

Previous investigations on forming of plain weft-knitted fabric composite sheets show the ease of stretching due to fabric loop straightening. Pure dependence on stretching alone, however, sets the limit to which the shell height can be further increased. Recent deep drawn knitted fabric composites give greater cup height in comparison to stretch formed cup. In this paper a method of predicting the achievable cup height is proposed with due consideration to the fabric structure and tool dimensions. Comparison between the theoretical and experimental cup height shows good agreement.

A novel multiaxial three-dimensional woven preform: Process and structure

2017 ◽  
Vol 37 (4) ◽  
pp. 247-266 ◽  
Author(s):  
Xinmiao Wang ◽  
Li Chen ◽  
Junshan Wang ◽  
Xintao Li ◽  
Zhongwei Zhang
Keyword(s):  
Cross Sections ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Woven Composite ◽  
Cell Geometry ◽  
Geometry Model ◽  
End Use ◽  
Experimental Values ◽  
Composite Samples ◽  
Good Agreement

A novel multiaxial three-dimensional woven preform and the weaving technique have been developed in this study. The preform exhibits remarkable designs, which is formed by multiple layers of different yarn sets, including bias (+bias/−bias), warp, and filling, and all layers are locked by Z-yarns These layers are arranged in a rectangular fashion and the layer number and the position of bias layer can be determined by the end-use requirements. A weaving process and machine are proposed to produce the preform. The weaving technique enables the insertion of many warp layers between two opposite bias layers. The microstructure of the preform was also studied. Microscopic evidence of the microstructure reveals that the cross-sections of Z-yarn are variable along its central axis due to the lateral compression forces of adjacent yarns from different directions. On the basis of microscopic observation, a unit cell geometry model of multiaxial three-dimensional woven preform is established, and a good agreement has been obtained between the theoretical and experimental values of the structural parameters of woven composite samples.

A general micromechanical model to predict elastic and strength properties of balanced plain weave fabric composites

2017 ◽  
Vol 51 (20) ◽  
pp. 2863-2878 ◽  
Author(s):  
MM Shokrieh ◽  
R Ghasemi ◽  
R Mosalmani
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Elastic Properties ◽  
Present Model ◽  
Micromechanical Model ◽  
Homogenization Method ◽  
Plain Weave ◽  
Weave Fabric ◽  
Fabric Composites ◽  
Out Of Plane

In the present research, a micromechanical-analytical model was developed to predict the elastic properties and strength of balanced plain weave fabric composites. In this way, a new homogenization method has been developed by using a laminate analogy method for the balanced plain weave fabric composites. The proposed homogenization method is a multi-scale homogenization procedure. This model divides the representative volume element to several sub-elements, in a way that the combination of the sub-elements can be considered as a laminated composite. To determine the mechanical properties of laminates, instead of using an iso-strain assumption, the assumptions of constant in-plane strains and constant out-of-plane stress have been considered. The applied assumptions improve the accuracy of prediction of mechanical properties of balanced plain weave fabrics composites, especially the out-of-plane elastic properties. Also, the stress analysis for prediction of strain–stress behavior and strength has been implemented in a similar manner. In addition, the nonlinear mechanical behavior of balanced plain weave composite is studied by considering the inelastic mechanical behavior of its polymeric matrix. To assess the accuracy of the present model, the results were compared with available results in the literature. The results, including of engineering constants (elastic modulus and Poisson’s ratio) and stress–strain behavior show the accuracy of the present model.

Moire´-Holographic Technique for Three-Dimensional Stress Analysis

1970 ◽  
Vol 37 (1) ◽  
pp. 180-185 ◽  
Author(s):  
C. A. Sciammarella ◽  
G. Di Chirico ◽  
T.-Y. Chang
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Reconstruction Process ◽  
Double Beam ◽  
Out Of Plane ◽  
Hologram Interferometry ◽  
Moire Method ◽  
Diffraction Patterns ◽  
Good Agreement ◽  
Three Dimensional Space

The moire´ method is combined with hologram interferometry to obtain the three displacements of an arbitrarily deformed plane in the three-dimensional space. Double beam interference patterns are utilized. The interfering beams are obtained from the diffraction patterns of a grating printed in the analyzed plane. The in-plane and the out-of-plane displacements are measured in separate steps and yield separate patterns. The patterns are generated by double exposure and observed by a wave front reconstruction process. The experimental results included in the paper show a good agreement with theoretical results, proving the feasibility of the proposed technique.

THEORETICAL PREDICTION OF DEBYE TEMPERATURE FOR MANTLE MINERALS AT HIGH TEMPERATURES

2011 ◽  
Vol 25 (12) ◽  
pp. 1593-1600 ◽  
Author(s):  
ANJANI K. PANDEY ◽  
ABHAY P. SRIVASTAVA
Keyword(s):  
Shear Modulus ◽  
Elastic Properties ◽  
Laboratory Data ◽  
Seismic Velocities ◽  
Mantle Minerals ◽  
Seismic Properties ◽  
Debye Temperatures ◽  
Temperature Ranges ◽  
Experimental Values ◽  
Good Agreement

The seismic properties of a material depend on composition, crystal structure, temperature, pressure and in some cases defect concentrations. Most of the earth is made up of crystals. The elastic properties of crystals depend on orientation and frequency. Thus, the interpretation of seismic data or the extrapolation of laboratory data requires knowledge of crystal or mineral physics, elasticity and thermodynamics. In the present work, we calculated the shear modulus, seismic velocities and Debye temperatures at different high temperature ranges. The temperature dependence of elastic properties such as shear modulus, seismic velocities and Debye temperatures has been measured using Hill's averaging method and other thermodynamic methods for five silicate mantle minerals viz. MgAl 2 O 4, Mg 2 SiO 4, Fe 2 SiO 4, Mn 2 SiO 4, and Co 2 SiO 4. The results are found to be in good agreement with experimental values.

Backward Extrusion of Internally Shaped Tubes From Round Billets

1984 ◽  
Vol 106 (2) ◽  
pp. 143-149 ◽  
Author(s):  
D. Y. Yang ◽  
C. H. Han
Keyword(s):  
Pure Aluminum ◽  
Three Dimensional ◽  
Mapping Function ◽  
Velocity Transformation ◽  
Backward Extrusion ◽  
Commercially Pure ◽  
Theoretical Predictions ◽  
Experimental Values ◽  
Punch Pressure ◽  
Good Agreement

An analytical method is proposed for estimating the steady-state punch pressure for three-dimensional backward extrusion (or piercing) of complicated internally shaped tubes from circular billets. A kinematically admissible velocity field is derived to formulate an upper-bound solution using velocity transformation and mapping function. The configuration of deforming boundary surfaces are determined by minimizing the extrusion power with respect to some chosen parameters. Experiments are carried out with commercially pure aluminum billets for internally shaped tubes at various reductions of area by using different sizes of shaped punches, such as square and regular hexagons. It is shown that the theoretical predictions for extrusion load are in good agreement with the experimental values.

Mechanical Reinforcement of Three-Dimensional Spacer Fabric Composites

2010 ◽  
Vol 654-656 ◽  
pp. 2604-2607 ◽  
Author(s):  
Shao Kai Wang ◽  
Min Li ◽  
Yi Zhuo Gu ◽  
Zuo Guang Zhang ◽  
Bo Ming Wu
Keyword(s):  
Failure Modes ◽  
Synergistic Effects ◽  
Three Dimensional ◽  
Compressive Load ◽  
Mechanical Reinforcement ◽  
The Core ◽  
Fabric Composite ◽  
Spacer Fabric ◽  
Fabric Composites ◽  
Foam Filling

Three-dimensional (3-D) spacer fabric composite is a novel lightweight sandwich structure, the reinforcement of which is integrally woven with two facesheets connected by continuous fibers (named piles) in the core. Usually the 3-D spacer fabric composite without extra reinforcement is called mono-spacer fabric composite, which provides outstanding facesheet / core debonding resistance. However, its mechanical properties cannot meet the demand of structure application because of the thin facesheet and low load-bearing capacity of high piles. Hence, two reinforcement methods were developed by laminating additional weaves at the facesheet and filling foam materials in the core to strengthen the facesheet and piles, respectively. This paper aims to investigate the influences of reinforcement methods on the mechanical behaviors and damage modes of 3-D spacer fabric composites under flatwise compressive, shear, edgewise compressive and three-point bending loads, by comparing with mono-spacer fabric composites. The results indicate that additional weaves reinforcement can enhance edgewise compressive and flexural properties effectively. Foam filling is one of the best options to improve the flatwise compressive and shear properties, and especially, there are synergistic effects between piles and foam under flatwise compressive load. Besides, the failure modes of reinforced and mono-spacer fabric composites are different.

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