Effect of residual stresses on the fatigue of butt joints using thermal elasto-plastic and multiaxial fatigue theory

This investigation performs a thermal elasto-plastic analysis using finite element techniques to analyze thermo-mechanical behavior and evaluate residual stresses in weldments. Ail effective procedure is also developed by combining finite elements and multiaxial fatigue theory while considering the welding residual stress as the initial conditions in accurately predicting the fatigue life of welded joints. Herein, the fatigue lives of butt-welded joints are forecast using the proposed procedure. The proposed procedure that followed the conventional strain-based method (maximum principal strain and von Mises effective strain) to predict the, fatigue life of the butt-welded joints was fairly sensitive to welding residual stress. Furthermore, the maximum principal strain method led to conservative life estimates and the von Mises effective strain method offered the best agreement with the experimental data of butt-welded joints. (C) 2002 Elsevier Science Ltd. All rights reserved.