動的陽解法FEMを基にした大規模構造のための溶接過渡変形・応力解析手法の提案

抄録

In the analysis of welding mechanics, it is difficult to analyze large-scale structures because of welding-specific moving local nonlinearity. In this research, the authors proposed a new numerical method for welding mechanics based on the Dynamic Explicit FEM. In the proposed method, the temperature step is divided into hundreds of time steps as implicit FEM and the displacements are computed for each time step based on dynamic explicit FEM until the whole system reaches the static equilibrium state. And, to achieve the static equilibrium state faster, modified mass and damping matrix are introduced. The modified mass and damping matrix are based on the Courant condition and the vibration theory, respectively. The proposed method and static implicit FEM are compared at the final path of multilayer welding of thick bead-on-plate to verify validity and accuracy. The transient and residual deformation and stress distribution of the proposed method show good agreement with those of static implicit FEM. In addition, the computing time and memory consumption of the proposed method are 1/12 and 1/40 times shorter than those of static implicit FEM, respectively, in 243,243 degree of freedom model. It is found that the proposed method has an advantage in large-scale analysis whose nodal points are more than tens of thousands.