How to provide base excitation 1G load in Direct Frequency Response Analysis?

Question

I am doing a simple FRA of cantilever beam.

In SPCD load collector I included the Gravity in vertical direction.

The simulation is solving, but base motion (where the beam is constrained) is not observed.

Request members support.

Thanks,

Jegan

Jegan cae · Answer

Hello Song,

Thanks for the suggestion.

I tried Modal based method with SPCD card (G load applied on BC node). Its working now.

Might have done some mistake in direct method I suppose.

Anyhow will try your approach as well.

Thanks.

Xiaolei · Answer

Hi Jegan,

For modal frequency response analysis, we can use PARAM,ENFMOTN,REL to request relative output.

https://help.altair.com/hwsolvers/os/topics/solvers/os/param_enfmotn_bulk_r.htm

But for direct method, it's not supported.

So I would suggest using modal method if possible.

Thanks.

Xiaolei