A micro-mechanical model for predicting the compressive strength of fibrous composite materials

Abstract

A micro-mechanical model is proposed for the prediction of the compressive strengths of unidirectional fibrous composite laminates. In these laminates, it is assumed that the fibers have a small misalignment angle which ranges from 1 to 5 ° from the vertical direction. A fiber shear buckling mode is considered in the model formulation which is assumed to cause large shear deformation. A basic energy approach is utilized to determine the critical buckling load. Both fiber and matrix strain energies within the composite and the external work due to applied loads are considered during deformation. The model is tested by using various types of composites: wood/ductile wax, spaghetti/paraffin wax, glass/epoxy and carbon/epoxy. Results of the proposed model are compared with results given by the Rosen and Wisnom micro-models and with available experimental data. It is found that the proposed model yields reasonable results for the composite materials investigated.