Robust locating research of welding fixtures for the aluminum alloy sidewall of a high-speed train body

The sidewall of a high-speed train body is welded by multiple hollow extruded aluminum alloy sheets. Due to the material characteristics of aluminum alloy, excessive welding deformation is easy to occur in the welding process of the sidewall. The welding quality of the sidewall is mainly guaranteed by fixtures, and the reasonable arrangement of sidewall fixtures can reduce the welding deformation. In this paper, two robust fixture design methods based on the Taguchi method and the double response surface method are proposed and compared. Firstly, a simplified shell finite element model of the sidewall is established and verified, and a welding deformation evaluation index of the sidewall is put forward. Secondly, based on the inside and outside table experimental design, the Taguchi method is used to design the robust parameters of sidewall fixtures, and robust locating parameters of sidewall fixtures are determined according to the SNR. Thirdly, the mean and standard deviation models of welding deformation evaluation index are established based on the double response surface method, and the robust design of sidewall fixtures are carried out with the minimization of the square sum of the mean close to the target and the standard deviation. Finally, by comparing the original scheme, the fixture design scheme based on the Taguchi method and the fixture design scheme based on the double response surface method, it shows that the robust design method of sidewall fixtures based on the double response surface method is more suitable for the robust fixture design of the sidewall. The proposed robust fixture design methods can also be applied to other similar problems.