Modification and application of a unit cell continuum model to predict the elastic properties of textile composites

The unit cell continuum model, presented by Foye, is based on the principles of finite element analysis using heterogeneous hexahedra brick elements to predict the elastic properties of textile composites. The use of heterogeneous elements, consisting of fibres and matrix, often introduces mathematical instabilities in the solution due to the large difference in the stiffness of the fibres and matrix. This can reduce the accuracy of the results. In this paper a solution is presented to this problem. The solution is based on a micro-level homogenization approach utilizing a fabric geometry model. Moreover, this approach is integrated with a geometric model, based on processing science modelling, to ensure accurate representation of complex fabric preforms. Test results for in-plane elastic properties of a five-harness satin weave carbon/epoxy composite and a three-dimensional weave E-glass/poly(vinyl ester) composite were compared with mechanical predictions using this approach and gave matching results.