I'm conducting a vibration FEA analysis to compare with results from a physical sine sweep vibration test. In the experiment, applying a 1G sine sweep excitation at a non-resonant frequency results in an acceleration response close to 1G.

In my FEA simulation, I first extract the natural frequencies using fixed boundary conditions. Then, I apply a 1G base excitation using the *STEADY STATE DYNAMICS, MODAL step. However, the acceleration output (A1, A2, A3) from Abaqus is nearly zero at non-resonant frequencies.

Could this be because Abaqus outputs relative acceleration (i.e., the response relative to the moving base), and I need to add the base acceleration (1G) back in to match the test measurements?

Does anybody have any thoughts or suggestions?

Thanks,

Sean