Orthogonal Woven Composites Research Articles

Shear Behavior of 3D Orthogonal Woven Fabric Composites under High Strain Rates

The shear behavior of 3D orthogonal woven composite materials at various strain rates is investigated using the punch shear method both for quasi-static and high strain rate tests. Shear behavior in warp and weft directions respectively at strain rates from 900 to 3400/s are tested using modified split Hopkinson pressure bar (SHPB). The quasi-static tests are conducted on an MTS 810.23 material tester and compared with shear behavior in high strain rates. The results indicate that the shear strain and stiffness are rate sensitive both in the warp and weft directions. The shear stiffness increases, and shear failure strain decreases with the increase of strain rate. However, the failure shear stress in the warp direction is rate-independent while it increases with the strain rate increasing in the weft direction due to the different rate-sensitivity of Twaron yarns and glass yarns. The shear failure becomes more severe as the strain rate increases both in the warp and weft directions. The failure is the punch shear in the warp direction and punch accompanied with crack in the weft direction at various strain rates.

Transverse impact behavior and energy absorption of three-dimensional orthogonal hybrid woven composites

Abstract The transverse impact behaviors of three-dimensional (3D) orthogonal hybrid woven fabric composites were tested on a modified split Hopkinson pressure bar (SHPB) apparatus. The load–displacement curves of the composites in transverse impact were obtained to analyze the strain rate sensitivity of energy absorption. It was found that energy absorption of the composites increases with the impact velocity (i.e., strain rate). The failure modes under quasi-static transverse loading are tensile failure on back side and compressive failure on the front side, while those in transverse impact are matrix cracking, fiber breakage and fiber pull-out. The 3D orthogonal woven composites have the same failure mode in the warp and weft directions. There is no delamination for the 3D orthogonal woven composites under transverse impact as observed in laminated composites.

Energy absorptions and failure modes of 3D orthogonal hybrid woven composite struck by flat-ended rod

Three-dimensional (3D) orthogonal woven composite has high stiffness, strength, and energy absorption capacity along X, Y, and Z directions because there are no crimps in yarn. This paper presents mechanical behaviors and energy absorptions of the 3D orthogonal hybrid woven composite under transverse impact and quasi-static loading by flat-ended rod. The failure load and energy absorption of the composite increase with the increase in loading rate. The damage morphology of the composite coupon manifests the compression failure in the front side and tension failure in rear side. There are no delaminations in the composite coupons for both quasi-static and impact loading for the existence of Z-yarn in fabric structure. This phenomenon manifests the potential application of the 3D orthogonal woven composite to impact resistance areas. POLYM. COMPOS., 27: 410–416, 2006. © 2006 Society of Plastics Engineers

Virtual Material Characterization of 3D Orthogonal Woven Composite Materials by Large-scale Computing

In this paper, the virtual material characterization of three dimensional (3D) orthogonal woven composite materials is investigated by large-scale finite element analyses to predict the elastic properties. To numerically model the complex geometry of 3D orthogonal woven composites, a unit structure including the stuffer yarns, filler yarns, weaver yarns, and the resin region is generated based on direct numerical simulation (DNS) and the unit structures with the same pattern are assembled into an orthogonal woven composite structure composed of several millions of degrees of freedom. The influence of the geometrical irregularities, such as the inconsistent tow spacing and the waviness of the filler yarn, on the mechanical properties are also discussed by separately generating the yarns and the resin. From the numerical examples, it is shown that the pattern of tow distribution affects the shear modulus, and the direct modeling of the wavy yarns can produce more accurate stiffness knockdown. It is also emphasized that large-scale numerical analyses can be one of the methodologies sufficient for the material characterization of the orthogonal woven composites and can be more applicable in the realistic structure subject to complex loading compared to the unit cell approach.

An Analytical Method for Thermoelastic Analysis of 3D Orthogonal Interlock Woven Composites

A three-dimensional woven composite thermoelastic model is presented for predicting the thermoelastic properties of three-dimensional orthogonal interlock woven composites. The model is based on two level discretization of the repeating unit cell. The repeating unit cell is discretized into sections, elements, subsections and subelements. Eight number architectures of three-dimensional orthogonal woven composites have been analyzed. Compliance averaging and stiffness averaging schemes have been used for the prediction of thermoelastic properties. For the same fiber volume fraction, three-dimensional orthogonal interlock woven composites show a significant increase in through-the-thickness properties without a comparable reduction in the in-plane properties.

Effect of weaving damage on the tensile properties of three-dimensional woven composites

This research paper examines the damage mechanisms and reductions to the tensile properties of E-glass yarns during weaving of three-dimensional (3D) fabrics for polymer-based composites. The paper also assesses the influence of weaving damage to load-bearing glass yarns on the tensile properties of 3D orthogonal woven composites. It is found that damage occurs to yarns at most stages of the 3D weaving process due to abrasion and breakage caused when sliding against the loom machinery. The abrasion damage causes a large reduction (∼30%) to the tensile strength of the dry woven yarns, although the tensile stiffness remains unaffected. The damage and reduction to the tensile properties of the dry yarns at different weaving stages are described. Tensile studies performed on single yarn/resin composites and larger coupons of 3D orthogonal woven composites reveal that weaving damage is responsible for a significant reduction to the tensile strength.

Evaluation of thermo-elastic properties of three-dimensional orthogonal woven composites

A homogenisation scheme is developed to evaluate the thermo-elastic properties of three-dimensional orthogonal woven composites. The coupling effects between thermal and mechanical behaviour in different directions are taken into account. In comparison to some other analytical models, the results obtained with the present scheme are shown to be in better agreement with FEM predictions and experimental data. In addition, effects of cross-sectional geometry of yarns on the thermo-elastic properties of the composites are also analysed.

Stress and Failure Analysis of 3D Orthogonal Interlock Woven Composites

A three-dimensional woven composite strength model is presented for predicting the failure behavior of three-dimensional orthogonal interlock woven composites under on-axis uniaxial static tensile loading and shear loading. The model is based on two-level discretization of the repeating unit cell. The repeating unit cell is discretized into sections, elements, subsections and subelements. The model predicts the stress levels at which the secondary failures take place at subelement level. The effect of secondary failure is considered for further analysis and the ultimate tensile strength and shear strength and the corresponding strains are predicted. A parametric study has been carried out for different 3D orthogonal interlock woven composite configurations. In general, it is seen that there is no significant reduction in the inplane elastic and strength properties for 3D orthogonal woven composites, compared to the corresponding cross-ply laminates made of unidirectional layers, but there is a significant increase in the through-the-thickness properties.

Stress and Failure Analysis of 3D Orthogonal Interlock Woven Composites

A three-dimensional woven composite strength model is presented for predicting the failure behavior of three-dimensional orthogonal interlock woven composites under on-axis uniaxial static tensile loading and shear loading. The model is based on two-level discretization of the repeating unit cell. The repeating unit cell is discretized into sections, elements, subsections and subelements. The model predicts the stress levels at which the secondary failures take place at subelement level. The effect of secondary failure is considered for further analysis and the ultimate tensile strength and shear strength and the corresponding strains are predicted. A parametric study has been carried out for different 3D orthogonal interlock woven composite configurations. In general, it is seen that there is no significant reduction in the inplane elastic and strength properties for 3D orthogonal woven composites, compared to the corresponding cross-ply laminates made of unidirectional layers, but there is a significant increase in the through-the-thickness properties.

Behavior of 3D orthogonal woven CFRP composites. Part II. FEA and analytical modeling approaches

Abstract In this paper, a 3D macro/micro finite element analysis (FEA) modeling approach and a 3D macro/micro analytical modeling approach are proposed for predicting the failure strengths of 3D orthogonal woven CFRP composites. These approaches include two different scale levels, macro- and micro-level. At the macro-level, a relatively coarse structural model is used to study the overall response of the structure. At the micro-level, the laminate block microstructure is modeled in detail for investigating the failure mechanisms of 3D orthogonal woven CFRP composites. The FEA and analytical models developed previously [Tan P, Tong L, Steven GP. Modeling approaches for 3D orthogonal woven composites, Journal of Reinforced Plastics and Composites, 1998:17;545–577] are employed to predict the mechanical properties of 3D orthogonal woven CFRP composites. All models presented in this paper are validated by comparing the relevant predictions with the experimental results, which were reported earlier in Part I of the paper [Tan P, Tong L, Steven GP. Behavior of 3D orthogonal woven CFRP composites. Part I. Experimental investigation, Composites, Part A: Applied Science and Manufacturing, 2000:31;259–71]. The comparison shows that there is a good agreement for the mechanical properties. An acceptable agreement exists for the failure strength in the x or stuffer yarn direction even though the FEA model gives a lower bound and the analytical model gives an upper bound. However, for the failure strength in the y or filler yarn direction, the difference between the predicted and experimental results is significant due to primarily ignoring of the waviness of filler yarn in the models. A curved beam model, which considers the waviness of the filler yarn, will be presented in Part III of the paper.

Models for Predicting Thermomechanical Properties of Three-Dimensional Orthogonal Woven Composites

Unit cell and laminate modeling approaches were previously developed for predicting the effective elastic constants of three-dimensional (3D) orthogonal woven fabric composites [1]. For both models, the finite element analysis (FEA) and theoretical analysis methods were proposed. In the FEA method, finite element meshes were generated using the commercial FEA software Strand6, while in the theoretical analysis methods, closed-form formulas were derived using elastic mechanics theory and the "X model," "Y model" and "Z model" [2]. In this paper, both the unit cell and laminate modeling approaches were used to predict the effective coefficients of thermal expansion (CTEs) for 3D orthogonal woven fabric composites. The present numerical study showed that there is a good agreement between the FEA and theoretical analysis results. Also, a good agreement was noted between the present predicted results and experimental results available in the literature. Parametric studies were conducted to investigate the effects of the yarn cross-sectional shape, lamina block layer number, lamina block thickness, through-the-thickness (or z) yarn volume fraction and its space (i.e., space between two adjacent z yarns) on the effective coefficients of thermal expansion. It is worth pointing out that the theoretical models and the relevant formulas for predicting the effective coefficients of thermal expansion can also be used to predict the effective coefficients of moisture expansion for 3D orthogonal woven fabric composites.

Modeling Approaches for 3D Orthogonal Woven Composites

In this paper, a unit cell model and a laminate model are presented for predicting engineering elastic constants of 3D orthogonal woven composites. For the unit cell model, one finite element analysis (FEA) and four theoretical analytical approaches were proposed. In the FEA approach, a finite element mesh of a unit cell was generated by interfacing an in-house computer code with the commercial FEA software Strand6, and then used to investigate the effects of some geometrical parameters on engineering elastic constants and yarn volume fractions. In the theoretical approaches, all four analytical methods were developed using the elastic mechanics theory and "X model," "Y model" and "Z model" developed previously [1]. For the laminate model, one FEA modeling approach and one theoretical method were proposed by introducing three new lamina blocks. The finite element analysis of a laminate block was conducted using Strand6 and the theoretical method was developed using the same theory as the unit cell model above. The effect of the warp lamina block layer number on engineering elastic constants was discussed using the theoretical method. Good agreement between the FEA and theoretical analysis results were achieved for both the unit cell model and the laminate model. In addition, the in-plane Young's moduli El and E2 predicted using the unit cell and the laminate models correlated well with the experimental results available in the literature [2].

The effect of free radicals and anti-oxidant during in vitro maturation and fertilization of porcine oocytes

Modelling the mechanical performance of textile composites is typically based on idealised unit cell geometry. However, 3D woven composites feature more complex textile architecture then 2D woven materials, and in reality nominally straight warp and weft yarns can also possess significant waviness. For such textiles, idealising yarns as straight entities becomes an oversimplification. In this study, the voxel method and a continuum damage model are used in a finite element analysis to compute stress–strain curves for an orthogonal 3D woven composite under tensile loading. The main goal of this study was to compare results produced using idealised geometry with realistic geometry obtained from detailed simulation of the preform during weaving and compaction. Significant variation in predictions was obtained using the different geometrical models. The idealised model lead to an overestimation of stiffness and strength compared to experiment due to the neglecting of yarn waviness, whereas the simulated geometry models produced more conservative results closer to experiment.