Influence of fiber spatial distribution in unidirectional composite cross-section on homogenized elastic parameters

The aim of this work is to analyze the influence of spatial distribution of fibers in unidirectional longfiber composite material on the mechanical behavior of a lamina using finite element models of unit cells (micromodels). The dependencies of effective elastic parameters of a lamina on degree of irregularity of spatial fiber distribution are investigated, proved and described. Degree of irregularity of real composite material cross-sections and the unit cells is described by a proposed parameter. This parameter expresses deviation of a given composite cross-section (2D geometry) from idealized regular hexagonal fiber distribution. Effective elastic parameters of 200 micromodels with geometries having different degrees of irregularity are calculated. A dependence between the parameter evaluating the cross-section irregularity and the spread (interval between extreme values) of the resulting effective parameters is obtained.