Numerical simulation for squeeze flow behaviour of carbon fibre sheet moulding compound

Abstract

Squeeze flow is one of the main deformation mechanisms in SMC compression moulding. This paper presents the development of a rate-dependent plasticity model for simulating the squeeze flow behaviour of a carbon fibre SMC under typical compression moulding conditions. The proposed model focused on the compressive stress–strain response of the SMC, taking into account the coefficient of friction at the SMC/mould interface, the apparent compressibility and the strain rate dependency of the SMC. The model was verified using a single-ply SMC squeeze flow simulation, where the predicted results of compressive force–displacement, the volume change of the SMC, and the in-cavity pressure distributions were compared with the experimental data. The simulation with combined compressibility and pressure-dependent friction gives better prediction in both compressive forces and pressure distribution. Furthermore, a multi-ply squeeze flow simulation was performed to validate the proposed model, and it was found that a more realistic representation of the SMC charge and a more accurate prediction of compressive forces were achieved by modelling the multi-ply charge as separated plies with varying thickness.