Spatially Averaged Local Strains in Textile Composites Via the Binary Model Formulation

A previously published computational model of textile composites known as the Binary Model is generalized to allow systematic study of the effects of mesh refinement. Calculations using different meshing orders show that predictions of local strains are mesh independent when the strains are averaged over gauge volumes whose dimensions are greater than or equal to approximately half the width dimensions of a single tow. Strains averaged over such gauges are favored for use in failure criteria for predicting various mechanisms of failure in a textile composite, including transverse cracking within tows, kink band failure in compression, tensile tow rupture, and shear failure. For the highest order representations (infinitely dense meshes), the generalized formulation of the Binary Model necessarily approaches conventional finite element meshing strategies for textile composites in its predictions. However, the work reported here implies that usefully accurate predictions of spatially averaged strains can be obtained even at the lowest level of mesh refinement. This preserves great simplicity in the model set-up and rapid computation for relatively large features of structural components. Calculations for some textile structures provide insight into the strength or relative absence of textile effects in local strains for different loading configurations.