Nonlinear Mechanical FE Analysis of Thin-Plate Complex Structures Using the Shell-Solid Mixed Method

Abstract

Abstract In the construction of ships and ocean structures, thin steel plates are welded in order to join parts. Due to the welding, deformations and residual stresses may occur. These deformations and residual stresses can cause problems in the assembly process. Therefore, the prediction of welding deformations and residual stresses is necessary in advance of production. Welding deformations and residual stresses can be predicted using thermal elastic plastic (TEP) finite element analysis (FEA). However, solid elements are used in the conventional analysis method of TEP-FEA. The modeling of the thin-plate structures using solid elements is very complicated and difficult. In addition, the number of elements increases when using solid elements compared to shell elements. This leads to an increase in the required computing resources. Therefore, an efficient modeling method is necessary for thin-plate structures. In the present research, in order to realize an efficient welding mechanics analysis method for thin-plate structures, the authors proposed an efficient FEA method for the welding mechanics problem for thin-plate complex structures using the proposed shell-solid mixed analysis method. For the shell-solid mixed analysis method, the multipoint constraint (MPC) technique was used in the finite element analysis to connect shell elements and solid elements. In order to compare the analysis accuracy with the conventional analysis, which uses solid elements, the proposed shell-solid mixed analysis method was applied to the fundamental welding mechanics problem of thin-plate structures. The results revealed that the proposed method has approximately the same analysis accuracy as the conventional method. These results indicated that the proposed method can effectively analyze the welding deformations and residual stresses in thin-plate complex structures.