Numerical Simulation Of Structural Optimization And Welding Deformation In Thin-walled Multi-welds Component

The continuous plate dryer which composed mainly by drying tray is a new energy efficient conduction drying equipment, and the drying tray has characteristics of thin-walled, multi-welds, large deformation and large-size. The structure form and welding process of drying tray were optimized with numerical simulation technology for the problems of structure design and welding deformation.The punching distance, sheet thickness and punch diameter of drying tray were optimized use of orthogonal design combined numerical simulation methods, and hydraulic experimental of the structure optimized was carried out. The results show that the structure of drying tray optimized able to meet the requirements of the mechanical properties.The welding process of drying tray was numerical simulated with the method of segmented moving heat source since there are large number of welds, that the welds at each punching are activated simultaneously, and the large segment of the welds are divided into small pieces, each weld are activated simultaneously to improve computational efficiency. The segmented moving heat source method is reasonable verified by the residual stress measurement of blind-hole method. The residual deformation distribution of numerical simulation and welding experiment is more consistent which proved that the numerical simulation of welding process is reasonable and effective.The equivalent model of drying tray was established to save computation and computing time, and fifteen kinds of welding sequences on welding residual deformations were simulated to optimize the welding sequence. The welding residual deformations of drying tray with same direction, opposite direction and reverse direction welding program were measured, and a welding technological process was developed.The results show that the optimal structural parameters of drying tray is that punching distance is120mm, punching diameter is25mm, sheet thickness is4mm; The maximum residual stress of drying tray after welding is529MPa which located the fixed position weld between the punching board and the upper cover, and the maximum residual stress of upper cover is233MPa which located the initial weld; The welding deformation of workpiece is bulging deformation upward along the center, the maximum deformation is22.8mm which located in the inner diameter. The deformation of same direction program is28.2mm; the deformation of opposite direction program is22.1mm, and the deformation of reverse direction program is22.1mm. The adoption of reverse direction welding programs can reduce the welding deformation effectively while the welding deformation was reduced by41.5%, and the production efficiency can be increased by more than30%through the development of welding technological process.