@Claudio Pedrazzi I can understand the general concept, sir.
In my case, vibrating motors have their own self-weight and distribution mass over at point A. Are these two factors will affect the mode shapes and natural frequency?
Another doubt is, I am using two exciters, so the excitation frequency is double the value ( 2x 16 - 32 Hz) or Not?
whether I have to apply the moment of the exciters or not?
Totally what are the inputs I should apply to get correct natural frequency modes.