Effects of Specimen Width and Specimen Length on Stress Intensity Factor Solutions for Spot Welds in U-Shape Specimens

In this paper, the stress intensity factor solutions for spot welds in U-shape specimens are investigated by finite element analyses. Three-dimensional finite element models are developed for U-shape specimens to obtain accurate stress intensity factor solutions. In contrast to the existing investigations of the stress intensity factor solutions based on the finite element analyses, various ratios of the sheet thickness to the nugget radius, the half width of the central square portions to the nugget radius and the half specimen length to the half specimen width are considered in this investigation. The computational results confirm the functional dependence on the nugget radius and sheet thickness of Zhang’s stress intensity factor solutions for U-shape specimens. The computational results provide a geometric function in terms of the normalized width of the central square portions and the aspect ratio of the bottom and top sheets of the U parts to Zhang’s stress intensity factor solutions for U-shape specimens. Finally, based on the analytical and computational results, the dimensions of U-shape specimens are suggested.