Thanks for your helpful reply

1. you split the 20 seconds into 4 groups, which means that it takes 5s for 80-110Hz with the sampling frequency 2200Hz and 2200*5=11000 data points, but if I would be interested in the breakpoints, which means that the next group will be 105Hz(can also be less or higher whenever it is less than 110Hz) to 140Hz. Do I understand your point correctly?

2. I try the acceleration with fixed support, the frequency sweep is from 80Hz to 200Hz, I give it 80000 data points, which is exactly 20 times higher during 20s time span, but the thing is that I found out the output is just copying the trend of the input. unlike the last time, you help me to create a constant 5g acceleration within 10s, the result of which looks very promising. Do you know the reason? I also attached the ANSYS file, If you have time, you could run it and take a look at it, The acceleration data I got is just to do twice derivative of the displacement forcing function.

3. If I give the fixed support, but at the same time, I also apply the displacement with only Z direction free to move, will it still work when both of them are input as the boundary conditions?