Assessment of the fatigue strength and residual life

For dynamically loaded welded structures, a fatigue or durability detection is often required. Basically a sufficient fatigue strength for the respective notch detail against the vibration load has to be detected over the entire lifetime. When SKI engineering company for coming local fatigue concepts apply beyond their performance on the (global) nominal stress concept.

The following is the butt weld shown above on the example, can be done as a fatigue evaluation based on the notch strain concept. In the following figures can be seen as the notch stresses and tolerable numbers of cycles are influenced by a unscheduled offset. In the present case, the lower weld toe is left decisive for the entire fatigue strength of the butt weld.

Notch stresses in a butt weld with unplanned displacement (stress plot)
Local assessment of the numbers of cycles (fatigue plot)