A micromechanics-based method for off-axis strength prediction of unidirectional laminae

A micromechanics-based method to predict the off-axis strength of unidirectional linear elastic laminae is presented. These composites fail by matrix cracking along a plane parallel to the fiber direction. The stresses in the matrix are calculated using a local stress analysis based on a concentric cylinder model. This model consists of a unique fiber embedded in matrix; both constituents are represented by cylinders. The stresses and strains from the concentric cylinder model are averaged over the volume of the matrix and used in a local failure function This failure function has the form of a reduced and normalized strain energy density function where only transverse and shear terms are considered. The off-axis strength prediction method is validated using data from the literature.