Modeling and optimization of welding fixtures for a high-speed train aluminum alloy sidewall based on the response surface method

In order to ensure the welding quality of a high-speed train body sidewall, a series of fixtures are needed to locate and clamp the welding parts in the sidewall welding process. The fixture layout has a significant effect on the welding deformation. In this research, a modeling and optimization method of welding fixtures for a high-speed train aluminum alloy sidewall based on the response surface method is proposed. Firstly, a simplified finite element model of the sidewall is analyzed by a thermal elastoplastic finite element method, and the accuracy of the finite element model is verified by comparing with the actual measurement data. Secondly, two key fixture locating parameters are optimized based on the consistency of fixture locating parameters. Finally, based on the difference of fixture locating parameters, a second-order polynomial welding fixture model is established by the response surface method, and a set of satisfactory solutions is obtained. The accuracy of this set of solutions is verified by the finite element analysis. Compared with the initial fixture layout, the welding deformation in the optimized layout is reduced by 192.18% indicating the feasibility of this modeling and optimization method.