Random Response Analysis using Abaqus

[y39chen]

Hi,

I am fairly new to Abaqus. I have a problem where I have a truss. I would like to applied an unit power spectral density to one point of the truss and find out its response (displacement) at the same point to find out its transfer function and produce a FRF graph.

So far, I used the random analysis solver in abaqus after the frequency step. In PSD definition, I define a PSD of 1 across the frequency of interested,and type = force. In correlation, I used correlated option. I defined a point load at the location of interested, and I output the U (displacement) and RU (RMS displacement) of the same point. Am I going about the problem the right way?

Also, the results are not what I expected. The displacment are orders of magnitude off. Do anyone know what I might have done wrong?

Thanks,

Yan