熱収縮法による溶接変形の簡易シミュレーションの建設機械構造物への適用

抄録

The thermal shrinkage technique, which uses shrinkage strain to calculate welding distortion, shows promise as a simple simulation for predicting the welding distortion of large weld structures. To date, we performed parametric study using thermal shrinkage technique for bead-on-plate welding and optimum input data settings, which were the shrinkage strain of −0.012 and a shrinkage zone in which the maximum temperature reached 500°C or more, was clarified. In this work, the thermal shrinkage technique with established input data settings was applied to a construction machinery structure to validate whether the input data settings obtained in the previous study of test pieces is applicable to large weld structures. Thermal elastic-plastic analysis considering moving heat source was also performed to compare the numerical results by the thermal shrinkage technique. Numerical results revealed that the displacement distribution of the construction machinery structure obtained by the thermal shrinkage technique was in good agreement with that obtained by thermal elastic-plastic analysis. In addition, the displacement in each welding pass obtained by the thermal shrinkage technique accurately reproduced that obtained by thermal elastic-plastic analysis. The calculation time of the thermal shrinkage technique was 1/6 for the construction machinery compared with thermal elastic-plastic analysis, which clarified that calculation time could be shortened. Our results demonstrate that the thermal shrinkage technique with optimum input data settings could be applicable to large weld structures to predict welding distortion.