Fatigue settings

- January 22, 2020 at 10:36 am
  
  dardaem
  Subscriber
  
  Hello
  
  If I have a stress and I want to calculate the fatigue for plus and minus 10% of that stress which is the loading type and settings on fatigue tool to use on Ansys?
  
  Thanks
- January 22, 2020 at 11:11 am
  
  peteroznewman
  Subscriber
  
  The stress was caused by a load. If the load magnitude was 1, then the load magnitude that causes a 10% higher stress is 1.1 and the load magnitude that causes a 10% lower stress is 0.9
  
  Use a Type = Ratio where the Scale Factor is 1.1 and the Loading Ratio is 0.9/1.1 = 0.818181
  
  You might also consider which mean stress theory to use.
  
  If this answers your question, please mark the Is Solution link below this post to mark this discussion as Solved, or ask a followup question.
- January 22, 2020 at 11:23 am
  
  dardaem
  Subscriber
  
  Thanks a lot.
  
  And if I want to calculate the mean and stress amplitude should I use the equivalent or principal stress results?
- January 23, 2020 at 1:27 am
  
  peteroznewman
  Subscriber
  
  Use Equivalent Stress.