Recently, I am focusing on the aerodynamic load of an FOWT subject to a prescribed displacement motion as a sine function. I found that the FAST code coupling to a seismic load module is very interesting, and it helps me to study on my topic. However, I am wondering the “ActDamp” variable that should be correctly defined in the input file (NRELOffshrBsline5MW_Onshore_Seismic.dat). According to the guideline of Seismic Loading for FASTmodule, this value is suggested as 60-70%. As my understanding, this value should be defined as 0% because my prescribed displacement motion is a sine function. Is it right? If no, how much is it in your opinion? In fact, I tried to investigate the effect of this variable on the aerodynamic loads, their magnitude is different.
I would be glad to hear your recommendation for this problem.