Abstract
The authors have investigated fatigue crack propagation behavior and fatigue life of welded joints under combined normal and shear stresses acting in phase through fatigue tests. In this study, methods of fatigue life assessment of welded joints under the combined stresses are investigated. Fatigue life assessment methods based on maximum principal stress range or normal stress range are reviewed. A method based on fatigue crack propagation behavior and the concept of maximum strain energy release rate is proposed. Using the proposed method, fatigue life under the combined stresses is in good agreement with that under normal stress, and thus fatigue design S-N curves of welded joints for the normal stress cycle can be applicable to the combined normal and shear stress cycles.
