Three dimensional finite element analysis of twill woven composite laminates

Woven fabric laminated composites are likely to play a key role in modern lightweight aerospace structures. Before these woven fabric laminated composites can be used in primary structural applications, predictions of elastic properties such as the moduli, Poisson's ratios from the weave architecture and the properties of the constituent materials are desirable. Many finite element models for plain weave, 5- and 8-harness satin weaves are available to predict these properties. However, very little work is reported in the area of three dimensional finite element analysis of twill weave. This paper addresses a basic development of three dimensional finite element model to predict the stiffness of the twill woven composites. The model takes into account effects of the actual fabric structure by considering tow undulations and continuity along both the fill and warp directions. Various tow cross sections are possible and can be easily incorporated for a particular application. The results obtained by using the present finite element model are compared with the experimental results.