Multiphysics simulations of cure residual stresses and springback in a thermoset resin using a viscoelastic model with cure-temperature-time superposition

摘要

Simulations of evolution of cure-induced stresses in a viscoelastic thermoset resin are presented. The phenomenology involves evolution of resin modulus with degree of cure and temperature, the development of stresses due to crosslink induced shrinkage, and the viscoelastic relaxation of these stresses. For the simulations, the detailed kinetic and chemo-thermo-rheological models for an epoxy-amine thermoset resin system, described in Eom et al. (Polym. Eng. Sci. 2000, 40, 1281) are employed. The implementation of this model into the simulation is facilitated by multiphysics simulation strategies. The trends in simulated cure-induced stresses obtained using the full-fledged viscoelastic model are compared with those obtained from two other equivalent material models, one involving a constant elastic modulus, and the other involving a cure-dependent (but time-invariant) elastic modulus. It is observed that the viscoelastic model not only results in lower estimates of cure-induced stresses, but also provides subtle details of the springback behavior.