Prediction of stiffness degradation in hygrothermal aged [θm/90n]S composite laminates with transverse cracking

The stiffness reduction of symmetric hygrothermal aged angle-ply laminates containing a cracked mid-layer is predicted by using a modified shear-lag model. The material properties of the composite are affected by the variation of temperature and moisture, and are based on a micro-mechanical model of laminates. This hygrothermal effect is taken into account to assess the changes in the longitudinal modulus due to transverse cracking. The obtained results represent well the dependence of the degradation of elastic properties on the cracks density and hygrothermal conditions.