Matrix damage of fibrous composites: Effects of thermal residual stresses and layer sequences

A simplified micromechanics model and a damage evolution function are incorporated into a finite-element analysis program for laminated fibrous composite structures in order to investigate the effects of microscale damages on the structural response. The computer program can analyze both fiber failure and matrix cracking. However, the present study focuses on matrix cracking. In the present study, two kinds of problems are solved using the computer program. The first study is to investigate effects of contiguous stacking of 90 ° layers in cross-ply composites on reduction of composite stiffness. The analyses show that more contiguous stacking of 90 ° layers in cross-ply composites causes a greater stiffness reduction for the same amount of matrix cracking. The second study investigates the effect of thermal residual stresses on the composite stiffness reduction. The results show that the thermal residual stresses play an important role in matrix cracking of cross-ply, fibrous composites.