
Re: About linear simulation
Anthony Botting Oct 30, 2012 9:00 AM (in response to Third J)It may not be unreasonable depending on forcing frequency and displacement amplitude.
If "omega" is the forcing frequency of vibration (radians/second), and "A" is the vibration displacement amplitude:
displacement: x(t) = A sin (omega*t)
velocity: v(t) = [omega*A] cos (omega*t)
acceleration: a(t) = [](omega)^2 *A sin (omega*t)
So the magnitude of acceleration can be quite large = (omega squared) * A.
For example, if forcing frequency, omega = 223 Hertz = 1401 radians/second, and forced vibration amplitude is A= 0.005 meter (5 millimeters), then:
Magnitude of acceleration (ARES) = (omega squared) * A = 9816 m/s^2 = 1,000 g's (approximately).
As a check you could also plot Displacement Resultant and Velocity Resultant and handcalculate the Acceleration Resultant to see if the values workout.
Also, if the forcing frequency is near or very near any of the structure natural vibration frequencies, the values can get very large (especially with no damping). You can list the structure natural vibration frequencies and see if any of them are near the forcing frequency.

Re: About linear simulation
Third J Oct 30, 2012 11:21 PM (in response to Anthony Botting)So,does acceleration decrease with increasing damping?
And where could I search the parameters of material damping?
Because I can't find any useful result about material damping for setting.
Thank you.
