Structural and Fatigue analysis of a Frame with Cutout

Concern has arisen that fatigue cracks might occur at the cutout as the service loads are increased. Since the loading is random in nature, it needs to be measured before a fatigue analysis can be carried out. This is done by three strain gauges during a few representative service cycles.

Then, a static model of the beam is built and solved to calculate, from the strain measurements, the stresses at the critical locations around the cutout.

A built-in function to perform rainflow counts on the stress history is then utilized. Here, load cycles based on the amplitude and mean stress are grouped together into bins. The accumulated Palmgren-Miner fatigue damage is then calculated by considering the contribution from each bin.

Boundary plot showing the von Mises stress. The results reveal that stress is mainly concentrated around the cutout.

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