Deformation mechanism and residual stress evolution of CFRP/rubber composite mandrels during thermo-chemo-mechanical manufacturing process

CFRP/rubber composite structures are widely adopted in mandrel design owing to their conformability and tunable stiffness. However, the mismatch between rubber vulcanization and prepreg curing may induce non-uniform deformation and process-induced stress accumulation during manufacturing. The coupled manufacturing behaviour of CFRP/rubber composite mandrels remains insufficiently understood, particularly under the simultaneous effects of rubber flow, mold contact, and prepreg curing. In this study, a thermo-chemo-mechanical coupled model is developed to investigate the deformation mechanisms and residual stress evolution of CFRP/rubber composite mandrels during manufacturing. The key contribution of the proposed framework is its unified treatment of multiple coupled manufacturing phenomena. It integrates heat transfer, vulcanization/curing kinetics, cure-dependent viscoelastic transition, mold-mandrel contact, and process-induced stress evolution. The results reveal that mandrel deformation is jointly governed by non-uniform thermal and vulcanization/curing evolution, rubber flow, and structural configuration. The final residual stress is mainly controlled by processing temperature and the stiffness mismatch between CFRP and rubber. Based on a multi-criteria evaluation, a processing condition of 180 °C and 0.7 MPa with an additional cooling time of 70 min is recommended as the optimal trade-off between efficiency and manufacturing performance. Experimental verification shows agreement with the simulation results, demonstrating the feasibility of the proposed framework.