Accuracy of 2D FE models for prediction of crack initiation in nested textile composites with inhomogeneous intra-yarn fiber volume fractions

The finite element simulation of nesting phenomena in textile composites is challenging, because of the difficulties that come with creating a 3D finite element model of a stack of nested plies. This paper proposes a 2D modeling approach for prediction of crack initiation locations in nested textile composites. The model is built up based on high resolution microscopic images of the polished edge of a tensile specimen and routines have been developed to take the inhomogeneous intra-yarn fiber volume fractions into account. The locations of critical stresses are compared with high-resolution microscopic images during tensile loading of the nested textile composite, and correlated with the locations of crack initiation. The methodology is validated against tensile experiments on a steel fabric reinforced epoxy laminate. The steel fabric has a high tendency for layer nesting and a high inhomogeneity in intra-yarn volume fractions, and it shows very good contrast in micro-tomography and microscopic images.