Stress intensities derived from stresses around a spot weld

The stress intensities (stress intensity factors and J-integral) around a s pot weld between sheets of dissimilar materials and different thicknesses a re generally expressed by the local stresses around the spot weld. The deri vations are established on an interface crack model which represents the ra dial cross-sections of the spot weld with the local stresses varying from p oint to point along the periphery of the nugget. The J-integral is determin ed analytically by applying the equilibrium conditions and the elementary p late theory to the model. The stress intensity factors are then separated b y following a load decomposition procedure and an analytic solution to inte rface cracks. The thermal stress intensities are also obtained for the spot weld. Application examples are given for a tensile-shear specimen.