Nodal velocity as boundary condition

[matparta]

Hello
I am interested in an harmonic analysis (frequency response) of a structure made of a mass connected to a frame. The mass can be modeled as a point mass, connected with rigid constrains (or distributed coupling) to the frame, which is modeled by shell elements.
I want to apply a velocity on the mass as a nodal boundary condition - in other words, I want to simulate a mass moving with given m/s at given frequency(ies) and I want to see the vibration velocity in a certain part of the frame.
Now, the FE softwares that I have checked do not have the possibility to apply such as boundary conditions (Ansys and Actran - Actran seems to be able to do it but it is cumbersome). I can only apply nodal displacement boundary conditions or nodal loads.
Why is that? How would you approach the problem?

I thought about converting the velocity to an acceleration and by knowing the mass of structure connected to a frame, convert that to a point load applied as a nodal load.
Thanks

 

[GregLocock]

why not turn it into a displacement at each frequency w using v=j*w*d?

It almost sounds like a forced response than a FR.

 

[BlasMolero]

Dear Matparta,
When the excitation is defined in amplitude of displacement or velocity in the frequency range the correct approach is to convert the excitation to acceleration and apply to the base of the frame structure using an RBE2 spider rigid element, not to the point mass: in the point mass is where you will read the response and plot vs. frequency of any response value you like : displacement, velocity or acceleration. This is the typical approach I do when solving dynamic modal frequency harmonic response analysis (SOL111) using Simcenter FEMAP with NASTRAN.
Best regards,
Blas.