Prediction of process-induced distortions and residual stresses of a composite suspension blade

Abstract

This paper deals with a universal simulation strategy for the calculation of process-induced distortions and residual stresses of a composite part. The mechanical material behavior is described by a viscoelastic material model depending on temperature and degree of cure . The required material parameters are derived by dynamic mechanical analyses. For the description of the reaction kinetic a phenomenological based model considering chemical and diffusion-controlled reactions is introduced. The reaction model parameters are fitted to isothermal and dynamic DSC measurements via global and local optimization. The thermal expansion and chemical shrinkage are characterized by thermal mechanical analysis and using the contact angle measurement method. The simulation strategy is demonstrated for a GFRP suspension blade for the automobile industry. Based on a sequential coupled temperature-displacement analysis thermal hot spots, temperature and degree of cure distributions as well as the final corresponding process-induced distortions and residual stresses are calculated and analyzed. The development of the stiffness and the correlated stress during the curing process are discussed in more detail. Furthermore, the effect of a degree of cure dependent stiffness on the stresses is investigated.