Dear @peteroznewman, I perfectly agree with you in performing two different analysis as you suggested.

Honestly, i tried a base excitation with a prescribed flat acceleration and with a tabular input, but i was not able. To approach the problem in a simpler way, I started approch the problem from a tabular input displacement with a full response analysis.

So, If you kindly suggest and explain in details how to perform a base excitation analysis as well as how to use a tabular input within the analysis, i will really appreciate.

I'm quite new in performing such analyses in Ansys APDL.