A MICROMECHANICAL MODEL FOR PREDICTING THE COMPRESSIVE STRENGTH OF FIBROUS COMPOSITE-MATERIALS

A micro-mechanical model is proposed for the prediction of the compres sive strengths of unidirectional fibrous composite laminates In these laminates, it is assumed that the fibers have a small misalignment ang le which ranges from 1 to 5 degrees from the vertical direction. A fib er 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 matri x strain energies within the composite and the external work due to ap plied loads are considered during deformation. The model is tested by using various types of composites: wood/ductile wax, spaghetti/paraffi n 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. (C ) 1997 Elsevier Science Limited.