Daniel Shaw
Ansys Employee
The FT calculates the fatigue damage caused by cycling between 2 result sets. It does not matter that the 2 result sets are within one WB system (say time step 1 and time step 2) or that they are in 2 separate systems (different Environments). It just matters that you specify 2 unique result sets in the Solution Combination and place the FT under that solution combination.nIt also does not matter, if the stresses in the result sets are caused by one load or multiple loads. The FT just considers the total stress state from each result set. The FT calculates the difference in component stress (delta SX, delta SY, etc.) between the 2 stress states, and then uses those delta component stresses to calculate the fatigue damage (and life) caused by alternating between those stress states.