Effect of plastic anisotropy on the limit load of highly undermatched welded specimens in bending

Plastic anisotropy is a typical property of many metals and it can have a significant effect of the limit load of structures. It is therefore of importance to evaluate this effect for typical geometries covered by compendia of flaw assessment procedures for limit load solutions. The present paper deals with a typical highly undermatched specimen in pure bending. It is assumed that the mismatch factor (the ratio of the yield stress of weld material to the yield stress of base material) is so small that plastic deformation solely occurs in the weld whereas the base material is elastic (rigid). The weld material obeys Hill’s quadratic orthotropic yield criterion. The variation of the upper bound bending moment with the thickness of the weld and anisotropic properties of the material is illustrated. Comparison with the isotropic case made shows that an effect of plastic anisotropy can be quite large.