Self-piercing riveting is a connection technology to achieve efficient connection of aluminum alloy plates, and the quality of the connection mainly depends on the rivet and mold parameters. This paper establishes a self-piercing riveting simulation analysis model based on the ALE method, and verifies the accuracy of the model by comparing the simulation and experimental results. Five parameters such as rivet length and mould radius are selected, and the undercut amount, bottom thickness, remaining thickness, and tensile shear capacity are used as evaluation indexes to research the main factors that affect the joint forming quality, and an effective optimization scheme is proposed.

In order to improve the quality of clinching joint, the parameters of mould should be considered synthetically. In this paper, the Hollomon flow stress model is used to simulate material deformation, while Arbitrary lagrangain-Eulerian method to adjust the distorted meshes for improving the accuracy of finite element simulation. The experiment of multi-objective optimization and finite element simulation method are combined to study the relationship underneath between the mould parameters and quality of clinching joint. As two of the most important quality related indicators, the neck thickness and self-lock value of clinching joint are optimized by the genetic algorithm and the optimal solution of the mould parameters are obtained accordingly. The final experimental results show the obvious quality improvement of clinching point after the optimization of the mould parameters. This progress provides reference for the multi-parameter optimization of the mould. 1

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Taking the front bumper system of a passenger car as the research object, a finite element model of pedestrian lower leg collision was first established, and the tibial acceleration at Y400 was found to be high in the performance analysis. Second, the sensitivity analysis was performed on the main parameters of the bumper system to determine the skin Thickness and foam density are the main influencing variables. Finally, a performance improvement scheme is proposed, and the lower leg tibia acceleration is reduced by 47.71% after the improvement, indicating that the scheme is conducive to lower leg protection.