An effective thermal-mechanical coupling method for simulating friction stir-assisted incremental aluminum alloy sheet forming

Incremental sheet forming (ISF) is considered as an advanced sheet metal-forming process for flexibly producing complex sheet metal parts. Numerical simulation is supposed to be able to effectively track the forming process, which is beneficial for ISF process optimization. Accuracy and efficiency in ISF process simulation have always been a research focus, especially for friction stir-assisted ISF (FS-ISF) with local friction heat involved, which brings a challenge to FS-ISF process simulation: how can this forming process be effectively simulated with acceptable accuracy? In order to accurately and efficiently predict the impact of local friction heat on FS-ISF process, a new thermal-mechanical coupling simulation method was developed. Based on a new equivalent method of the thermal field on the geometrically compressed tool and scaling of thermal conductivity of sheet metal, the simulation model was proposed and verified. Comparison with the experiment results of AA2024-T3 FS-ISF demonstrates that the optimal simulation model can improve computational efficiency by 316% and simulate FS-ISF process with promising accuracy, which provides a potential tool for virtual check of the feasibility of FS-ISF process design and optimization with thermal field involved.