The Effect of Matrix Shrinkage on Damage Accumulation in Composites

Abstract

This study addresses residual stress and its effect on the performance of thermoset filamentary composites. Both cure shrinkage and thermal shrinkage in the matrix generate various residual stresses. In this work, a molecular additive was used to nearly eliminate the cure shrinkage of the cast thermoset resin and thereby to significantly reduce the residual stress in the composite. In spite of the reduction in residual stress, the damage accumulation behavior was un changed : transverse cracking studies of (02/902) s laminates showed identical crack onset and crack accumulation in both control and experimental composites (with and without additive, respectively). The surprising lack of effect of reduced residual stress on damage accumulation is explained by considering the effect of the additive on elastic constants and fracture sensitivity.