Reply To: PSD (random vibration) and Acceleration on a body (harmonic response)

[dlooman]

The acceleration of the motor is obtained by applying a force equal to the desired acceleration divided by the motor mass.  Even though the acceleration is actually at the motor.  Applying a base acceleration should produce the same relative results.  The only error is that the base acceleration is applied to the entire model.  Here are commands that apply a pressure psd based on a unit pressure applied in the modal:

sfdele,all,all
psdunit,2,press
lvscale,1! scale pressure from modal
psdfrq,2,,10,50,100,500,1000
psdval,2,0.01,0.02,0.022,0.042,0.03
pfact,2,node! nodal excitation
!dmprat,.01 ! damping ratio
psdcom
solve