The effect of deformation-induced change of fiber orientation on the non-linear behavior of polymeric composite laminates

Effects of deformation-induced fiber orientation change and processing-induced thermal residual stresses on the non-linear behavior of IM7/5260 and AS4/PEEK composite laminates have been investigated. An overstress viscoplasticity model was used to describe the rate-dependent non-linear behavior of the composite lamina, and the laminate was modeled with the classical laminated-plate theory. The thermal residual stresses were calculated by using thermoelasticity. It was found that for certain laminates, the change of fiber orientation induced by deformation has a significant effect on the non-linear behavior of the laminate at relatively high strain levels and that thermal residual stresses played a more important role at lower strain levels.