Thank you for your reply.

So what I understand is that no matter the loads were used in the structural analysis, as we are in linear analysis, Workbench will retrieve the stress of whole elements and will use the “history-data” like a factor to calculate the new stress in each elements and that at each point of the history-data file. 

And it will determine the damage at each step and with a summation using Milner rule it will give me the life of the part. 

But if no matter the loads we use in the first structural simulation, why when I changed it the results are not the same ? 

And So what is the “scale factor” under my history data file location in Ansys WB ? 

Best regards