Short fatigue crack growth in welded joints described by the effective cyclic J-integral

Abstract

Abstract. The purpose of the present contribution is to predict the fatigue life of welded joints by using the effective cyclic J-integral as crack driving force. The plasticity induced crack closure effects and the effects of welding residual stresses are taken into consideration. Here, the fatigue life is regarded as period of short fatigue crack growth. The node release technique is used to perform finite element based crack growth analyses. For fatigue lives calculations, the effective cyclic J-integral is employed in a relation similar to the Paris (crack growth) equation. For this purpose, a specific code was written for the determination of the effective cyclic J-integral for various lifetime relevant crack lengths. The effects of welding residual stresses on the crack driving force and the calculated fatigue lives are investigated. Results reveal that the influence of residual stresses can be neglected only for large load amplitudes. Finally, the predicted fatigue lives are compared with experimental data: a good accordance between both results is achieved.

Fatigue of welded joints described by elastic‐plastic fracture mechanics

“…Dr The numerical fatigue life results were compared with experimental data: a good accordance between numerical and experimental results was achieved for both stress relieved and as-welded (shown in [27]) specimens. Thus, ΔJ eff is obviously an appropriate parameter for calculations concerning fatigue life prediction in welded joints.…”

“…Thus, a good accordance between both results is achieved. More comparisons can be found in [27] including results for non-stress relieved specimens, for R = 0 loading, and for weldments made of steel S690.…”