WELD CRACK AND OPENING AND CLOSING BEHAVIOR OF ROOT GAP DURING WELDING UNDER CYCLIC LOADING

Abstract

 This study investigated opening and closing behavior of root gap and weld crack occurance in slit-welding under cyclic loading through welding tests and thermal elasto-plastic finite element analysis. Sectional observations after the welding test revealed that the crack occurance highly depends on the magnitude of root gap opening displacement and loading frequency in welding process, and also restraint intensity of slits. Then, through the simulation of welding under cyclic loading, it was clarified that root gap opening behavior during welding changes due to the restraint intensity of the slit, which correlates the tendency of the crack occurance under different restraint conditions. Based on the test and analysis results, a conditional expression for the weld crack occurrence consist of the initial root gap opening displacement, loading frequency and restraint intensity of slits was obtained, and its validity was verified by the experiments.