The influence of residual stresses implicated via cure volume shrinkage on CF/VEUH—composites

This paper presents a thermal finite element analysis (FEA) of a unidirectional carbon fibre reinforced vinylester urethane hybrid matrix system. The evolution of the thermal residual stresses due to the mismatch in the coefficient of thermal expansion (CTE) of the single components in the cooling phase have been investigated. Additionally, the cure volume shrinkage was implemented into the FE-model. The model allows the transition of the homogeneous unidirectional composite material properties on a microscopic spot, where the properties of the fibres and the matrix can be considered separately. It could be shown, that the cure volume shrinkage (CVS) has a dramatic effect on the fibre/matrix interface region due to radial compression stresses along the fibre. Further, this may lead to microcracking or fibre/matrix debonding before any kind of load is applied to the material.