A dual-scale three-dimensional thermo-viscoelastic model for the hot stamping simulation of thermoplastic composites

Existing hot stamping simulations are performed at the macroscopic scale, making optimizing process parameters for a new composite system time-consuming. This paper develops a dual-scale three-dimensional thermos-viscoelastic model based on a numerical homogenization approach to accurately predict the structural deformation of thermoplastic composite laminates during hot stamping. The viscoelastic homogenization model is developed on representative volume elements using temperature-dependent viscoelastic parameters determined from thermo-mechanical tests. The effective properties of the composites are identified from the homogenization results, which are then combined with the experimentally measured thermal behavior into a numerical model of the hot stamping process. The developed model is validated by the agreement between the finite element homogenization results and the predictions made using the determined parameters. The simulated warpage of the molded part also agrees well with the experimental measurements. The developed dual-scale model can be used to predict the effective thermomechanical properties of composites. Moreover, it can also be integrated into numerical tools for structural design and process optimization of thermoplastic composites.