Abstract
The thermal elastic-plastic analysis for the welding transient and residual stresses and deformations needs the huge computation time to obtain the accurate results. The main cause is that the increment of temperature has to be small enough to calculate accurately. In this study, the thermal elastic constitutive equation and the thermal elastic-plastic constitutive equation are refined so that the very large increment of temperature can be used. Moreover, in the latter, the definition of differential coefficient of the yield stress for change of temperature is modified to be ingenious. The new constitutive equations are introduced to the FEM program.
Simple typical problem of thermal elastic-plastic analysis was calculated to confirm the reliability and the accuracy of the above theory. Then, some complex welding problems were analyzed. The welding residual stresses and deformations were compared with the accurate results obtained using small temperature increment. As a result, it was confirmed that the computation time is very largely shortened, compared with the usual incremental method using small temperature increment, keeping the high accuracy.
