Consider fracture-mechanical support factor

The FVA guideline can consider the fracture-mechanical support effect as a supplement to the calculation concept. Phenomenologically, this describes the effect that fatigue cracks (also microcracks) grow more slowly in a component in which the stress distribution is inhomogeneous than in homogeneous stress fields. 

Activating this switch increases the local material strength in the notch root of the component by a factor of n_bm. 
The fracture-mechanical support factor only influences the strength for very sharp notches (very high stress concentration factors) and, as recommended in the FVA guideline, is calculated based on the 7th edition of the FKM Guideline (2020).