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Ansys Learning Forum › Forums › Discuss Simulation › LS Dyna › Problems with fatigue calculations › Reply To: Problems with fatigue calculations

June 3, 2024 at 8:46 pm
igandiko
Ansys Employee

Hello, how do the element stress results compare to the S-N curve? Do the elements showing low fatigue life have higher stresses/high damage ratio? 

The expected fatigue life is computed as exposure time (in time domain, it is defined by termination time by *CONTROL_TERMINATION, also see texpo paramter) divided by cumulative damage ratio.

Regarding your question 3, expected fatigue cycles are computed as "expected fatigue life" times “zero-crossing frequency with positive slope”. For d3ftg generated in a time domain fatigue analysis, only cumulative damage ratio and expected fatigue life are provided. There is no “zero-crossing frequency” so no “expected fatigue cycle” is provided.