Transverse cracking of cross-ply laminates: A computational micromechanics perspective

Abstract

Transverse cracking in cross-ply carbon/epoxy and glass/epoxy laminates in tension is analyzed by means of computational micromechanics. Longitudinal plies were modeled as homogenized, anisotropic elastic solids while the actual fiber distribution was included in the transverse plies. The mechanical response was obtained by the finite element analysis of a long representative volume element of the laminate. Damage in the transverse plies was triggered by interface decohesion and matrix cracking. The simulation strategy was applied to study the influence of ply thickness on the critical stress for the cracking of the transverse plies and on the evolution of crack density in 02=90n=2

s laminates, with n = 1, 2, 4 and 8. It was found that the transverse ply strength corresponding to the initiation and propagation of a through-thickness crack was independent of the ply thickness and that the transverse strength of carbon/epoxy laminates was 35% higher than that of the glass fiber counterparts. In addition, the mechanisms of crack initiation and propagation through the thickness as well as of multiple matrix cracking were ascertained and the stiffness reduction in the 90 ply as a function of crack density was computed as a function of the ply thickness.