Evaluation of process induced residual stresses in continuous fiber-reinforced hybrid thermoplastic composites

The mechanical behavior of hybrid thermoplastic composites can be strongly influenced by process induced residual stresses. In this work studies for the evaluation of deformation and residual stresses are presented. The studies performed on a material consisting of a pure polypropylene layer and a glass fiber reinforced UD-Tape include measurements of the deformation, bending tests, residual stress measurements and accompanying finite element simulations. The results show that significant deformations and residual stresses exist, which are strongly influenced by the anisotropic material behavior of the thermoplastic laminate. It can be seen that annealing influences the deformation and the strength of the hybrid specimen.