Research On Modeling And Optimization Of Spotweld On Vehicle Front Longitudinal-beam Based On Crashworthiness

With the increasing of vehicle ownership, traffic accident has become a serious problem in the world. Many people annually die in the traffic accident, and traffic accident has brought a serious disaster to people's lives and property. With the loss of accident increasing greatly, the research of vehicle crash safety performance and improvment of the vehicle crashworthiness become an important issue for motor companies in the world. Today, strict crash safety statutes were established in the major vehicle manufacturing countries and the vehicle products must meet the standard.Based on the drop-weighted tests of the thin-walled column, three finite element models of spotweld are built, and the comparative analysis is carried out, including the force/distance curves, peak force, average crash force, compression, and mode of deformation. The spotweld model which is suitable for vehicle crashworthiness anlysis is found. The spotweld failure is common in the vehicle crash tests. Based on setting up different failure forces, the effect of spotweld failure to the crashworthiness is analysed. According the characteristic of research on crashworthiness, the method of optimization is used which consists of constructing the response surface model on design of experiment. The crashworthiness of the typical thin-walled column is optimized to study the effect of dimension parameters and the layout of spotweld on crashworthiness and acquire the optimized design parameters. The risk of spotweld failure is decreased, with the improvement of crashworthiness.Finally, to the problem of spotweld failure and HIC exceeding standard in the state statute test for a minbus, the vehicle front crash finite element model is established, and the optimization method is implemented in the optimal design of the front rail. The test results show that the front rail is compressed normally, the spotweld failure isn't found and the HIC of dummy meets the demand of state statute. The vehicle passes the test successfully. The study indicates that the method is of great guiding value to the prophase design of vehicle passive safety.