Research On The Performance Of Self-piercing Riveting And Its Application On Front Longero Simulation

In order to satisfy increasingly stringent emission regulations,how to minimize the weight of the vehicle while ensuring the strength of the vehicle has become a major issue in current automotive design.Compared with the structural optimization of body parts that are not ideal for weight reduction,more and more auto companies have used new materials as the main way to reduce the weight of the car body.The use of new materials has brought significant results to the lightweight of the car body,and the application of steel and aluminum hybrid bodies in the field of passenger cars is becoming more and more common.How to reliably and firmly connect different materials has become the main problem facing steel and aluminum hybrid body.In this paper,the most widely used self-pierce riveting technology in steel and aluminum hybrid body connection is selected as the research object.The influence of self-pierce riveting process parameters on joint performance and the application of simplified model in body modeling are discussed.The finite element simulation of the self-piercing riveting process and the failure process of different conditions of Q235 and 5754 aluminum alloy sheets was carried out by Simufact.forming software.The simulation results and load-displacement curves of the self-piercing riveting and joint failure process are analyzed.The effects of different process parameters on the performance of self-pierce riveted were studied by orthogonal test and the optimum die process parameters under the riveting combination were determined.The simulation effect of self-pierce riveted joint failure behavior was verified by LS-DYNA using two combinations of HEX8 solid element with MAT-SPOTWELD material model and keyword constraint CONSTRAINED_SPR2.The failure parameters of two simplified models were calibrated by means of a self-piercing riveted failure solid model.Compare the load-displacement curve of the simplified model under three loading conditions with the solid model.Determine CONSTRAINED_SPR2 as the best simplified model for self-piercing riveted joints.According to the calibrated optimal simplified model of self-piercing riveting,A steel-aluminum mixed front longeron model with self-piercing riveting was established and compared with the steel front longeron connected by spot welding.The results show that the steel-aluminum mixed front longeron is better than the steel front longeron in terms of energy absorption characteristics and light weight,and the rivet spacing of the steel-aluminum mixed front longeron is optimized.