A Study on the Distribution of Welding Residual Stresses in Laser Welds with the Nail-head Shape

Nail Head 형상을 가지는 레이저 용접 단면부의 잔류응력 분포 특성에 관한 연구

During the laser welding, weldments are suddenly heated by laser beam and cooled. This phenomenon gives occasion to complex welding residual stresses, which have a great influence on structural instability strength, in laser welds. However, a relevant research on this field is not sufficient until present and residual stress measurements have experimental and practical limitations. For these reasons a numerical simulation may be attractive in order to solve the residual stress problem. In order to determine the distribution of heat and welding residual stresses in laser welds with the nail-head shape, authors conduct the finite element analysis (two-dimensional unstationary heat conduction & thermal elasto-plastic analysis). From the result of this study, we can confirm the stress concentration is occurred at the place of melting line shape changed in laser welds with the nail-head shape.