THE EFFECT OF RESIDUAL-STRESSES AND WELD GEOMETRY ON THE IMPROVEMENT OF FATIGUE LIFE

In this paper, the effect of residual stresses and weld geometry on th e fatigue life of butt welded joints was studied by developing an anal ytical model using Linear Elastic Fracture Mechanics (LEFM), superposi tion and finite element approaches. Various configurations of residual stresses and weld geometry in butt welded joints were considered and corresponding effective stress intensity factors were calculated by us ing Bueckner's and Kanazawa's weight functions for an edge and a centr al through-thickness crack in finite plate respectively and Newman-Raj u's empirical equation was used for semi-elliptical surface crack. Fat igue life of bun welds subjected to various weld geometries and residu al stress configurations in as-welded condition and post-weld treated condition were calculated by using Paris' law with the effective range of stress intensity factor for zero-to-tensile loading (R=0) and comp ared with the available experimental data.