FEM simulation of a thermosetting epoxy matrix: Application to internal stresses

A novel approach has been developed to simulate internal stress growth during the curing of thermosetting systems. Couplings between the thermal, the chemistry and the mechanics were taken into account. Especially, heat produced by the thermosetting reaction was considered for the cure kinetics simulation. As a consequence, chemical shrinkage and thermal properties evolutions during the curing were obtained from the degree of cure computed at each time of the curing. Mechanical characteristics evolution with temperature and degree of conversion of the chemical reaction were deduced from DMA-TMA experiments. The numerical solving of the coupling problem was performed with the finite element software Abaqus. Simulation results for internal stress developments were validated by failure prediction for the Pyrex test tube containing the resin as observed experimentally. It confirms the validity of the FEM model for cure simulation and internal stress prediction.