Influence of Stacking Sequence on the Transverse Matrix Cracking in Continuous Fiber Crossply Laminates

The influence of stacking sequence to the transverse matrix crack was studied experimentally and analytically. Five crossply laminates of GR/BMI and GL/BMI composites were tested. Stacking sequence was found to have a significant effect on the matrix crack growth in composite laminates, it is behaved by the thickness effect to the cracked 90° plies. If the total volumes of the 00 and 90° plies are identical but the stacking sequences are designed to be different, the matrix crack growth processes are quite different. The 90° layer with smaller thickness has the higher cracking loading, matrix crack growth rate and final saturation crack density. Although stacking sequence affects the damage material state of the matrix crack, a final damage mechanics state may exist in the matrix crack growth for the laminates with the same total volumes of the 0° and 90° plies but with different stacking sequences, this damage state is characterized by the final residual laminate stiffness and seems to be independent of the laminate stacking sequence. This phenomenon can be accounted by a modified shear-lag model. Further study shows that the stiffness degradation of the cracked 90° plies has a low boundary which is independent of the laminate layup and material.