In the preceding papers, the author and his colloborators reported the following resnlts, obtained by tensile tests of transversely-welded wide plates without any artificial notch, that brittle fracture in welded structures using some high strength steels under some conditions initiated at the fusion line of the weld-joint, and that strain concentration at the fusion line induced by welding distortion was one of the most important factors to fracture.
In this paper, the author studied theoretically and experimentally the strain concentrations at weld-joints with verious types of initial distortions in flat plates and in cylindrical and spherical shells.
The theoretical formulas presented in this paper, together with the testing method proposed in the preceding paper, would be applicable to various welded structures to prevent brittle fracture initiation which is characteristic to welded structures.