Numerical simulation on notch size and shape effects of fiber-reinforced composite laminates

A 3D finite element model was developed in this work by considering damage modes like matrix cracking, fiber breakage, intra-ply splitting and inter-ply delamination. The notch size effect and notch shape effect of tensile quasi-isotropic composite laminates ([45/0/-45/90]_2S) with central holes and central cracks were studied by the finite element model. The simulation results indicate that the damage strength of the laminates decreases with the increasing of notch size. However, the laminates with central cracks always show higher damage strengths than those with corresponding central holes for the laminates studied in this paper. A further investigation of the finite element simulation results shows that subcritical damage forms earlier in cracked laminates with larger subcritical damage zones. The subcritical damage will significantly alleviate the stress concentration at the notch tip, and therefore make the cracked laminates exhibit higher damage strengths.