weave, architecture, yarn crimp, and the various mechanisms of energy absorption of the fabric, discussed later. To briefly compare various commercial brands of fabrics, Zylon woven fabrics absorb nearly twice the energy per unit areal density specific energy absorbed SEA than both Kevlar and Spectra, when gripped on all four edges, and almost 12 times that of aluminum fuselage skin. The ballistic impact performance of PBO systems is substantially superior to Kevlar 29 systems and marginally better than Kevlar KM2 systems 4. It is reported in Ref. 5 that Spectra fibers are ten times stronger than steel. Previous review work includes a database of early ballistic fabric research by Cunniff 6, and the mechanisms influencing ballistic performance of woven fabrics by Cheeseman and Bogetti 7.

Ballistic Impact of Dry Woven Fabric Composites: A Review

This work presents a computational material model of flexible woven fabric for finite element impact analysis and simulation. The model is implemented in the non-linear dynamic explicit finite element code LSDYNA. The material model derivation utilizes the micro-mechanical approach and the homogenization technique usually used in composite material models. The model accounts for reorientation of the yarns and the fabric architecture. The behaviour of the flexible fabric material is achieved by discounting the shear moduli of the material in free state, which allows the simulation of the trellis mechanism before packing the yarns. The material model is implemented into the LSDYNA code as a user defined material subroutine. The developed model and its implementation is validated using an experimental ballistic test on Kevlar woven fabric. The presented validation shows good agreement between the simulation utilizing the present material model and the experiment. Copyright © 2001 John Wiley & Sons, Ltd.

Computational micro-mechanical model of flexible woven fabric for finite element impact simulation

Development of reliable modeling methodologies for engine fan blade out containment analysis. Part II: Finite element analysis

Meshfree modeling and homogenization of 3D orthogonal woven composites

A novel approach is combined with the generalized method of cells (GMC) to predict the elastic properties of plain-weave polymer matrix composites (PMCs). The traditional one-step three-dimensional homogenization procedure that has been used in conjunction with GMC for modeling woven composites in the past is inaccurate due to the lack of shear coupling inherent in the model. However, by performing a two-step homogenization procedure in which the woven composite repeating unit cell is homogenized independently in the through-the-thickness direction prior to homogenization in the plane of the weave, GMC can now accurately model woven PMCs. This two-step procedure is outlined and implemented, and predictions are compared with results from the traditional one-step approach as well as other model and experimental results from the literature. Full coupling of this two-step technique within the recently developed Micromechanics Analysis Code with GMC software package will result in a widely applicable, efficient, and accurate tool for the design and analysis of woven composite materials and structures.

Micromechanics-Based Modeling of Woven Polymer Matrix Composites

This paper presents two newly developed micromechanical models for the analysis of plain weave fabric composites. Both models utilize the representative volume cell approach. The representative unit volume of the woven lamina is divided into subcells of homogeneous material. Starting with the average strains in the representative volume cell and based on continuity requirements at the subcell interfaces, the strains and stresses in the composite fiber yarns and matrix are determined as well as the average stresses in the lamina. Equivalent homogenized material properties are also determined. In their formulation the developed micromechanical models take into consideration all components of the three-dimensional strain and stress tensors. The performance of both models is assessed through comparison with available results from other numerical, analytical, and experimental approaches for composite laminae homogenization. The very good accuracy together with the simplicity of formulation makes these models attractive for the finite element analysis of composite laminates.

R. Tanov

Papers

Computationally Efficient Micromechanical Models for Woven Fabric Composite Elastic Moduli