Numerische Schweißsimulation gekoppelt mit einem anschließenden Hämmerprozess und integrierten lokalen Ermüdungsberechnungen

Numerical welding simulation coupled with a hammer peening procedure and local fatigue assessments.

Due to the post weld treatment the fatigue strength of welded joints can be enhanced in principal, if the weld toes are the most critical hot spots. But the fatigue life can not be increased significantly when the crack initiation starts at the untreated weld root. This paper provides detailed information about experimental and numerical investigations of an arc welding process followed by a process of hammer peening. The experiments were carried out on steel plates with single side butt welds. After welding the weld toes were treated by highfrequency hammer peening. However, the welding and fatigue tests were used as verifications for numerical welding simulations coupled with a hammer peening procedure and local fatigue calculations. The objective was to analyze the difference in fatigue strength between as welded and treated conditions. Therefore the change of residual stresses and notch geometry are the most important effects on the fatigue life for welded joints with and without post weld treatment. Within a fatigue tool the residual stresses and geometry of the notch can be considered in numerical simulations with local fatigue approaches. The total fatigue life was assessed by adding crack initiation life calculated with notch strain approach and crack propagation life calculated with crack propagation approach. Finally the coupled simulation provides not only stress plots but also fatigue plots for the whole welded joint under consideration of as welded and treated conditions after hammer peening.