Hi

I would like to perform dynamic analysis of a plate, but first, I’m practising on a beam model. And there is a problem already.

I got really strange results from Modal Analysis. For default settings displacement in the middle of a beam’s span is:

Load is harmonic P=A*sin(w*t) so I expected harmonic response. Can it be because to small time increment delta_t=1e-3 ?Do You got idea, why response is not as harmonic as the load? Is there a rule to chose time increment in dynamic analysis?

IF you got some material I would more than appreciate.

Cheers