Property degradation of anisotropic composite laminates with matrix cracking (I) -: Constitutive relation developing for (0m/90m)s cracked laminates by stiffness partition

The study on property degradation of damaged composite laminates is extended to anisotropic laminates with matrix cracking. In (1) of the paper an idea of "stiffness patition" is proposed to deal with the puzzle that the in-plane normal response is coupled with the shear response of the laminates. For (theta(m)/90(n))(s) laminates containing transversely cracked layers under general in-plane loading, the constitutive relations are derived and the effective stiffnesses are expressed as the function of crack density.