natural frequency for cantilever beam mounted on a vibration isolation pad
natural frequency for cantilever beam mounted on a vibration isolation pad
(OP)
The problem I have is finding the natural frequency for a cantilever beam mounted on a vibration isolation pad. I first modeled a cantilever beam fixed at one end and found the natural frequency using the standard formula Link Based on the frequency, I simplified the system into a mass spring system, by back calculating a stiffness value k1 using f = sqrt(k1/m). Now, assuming my vibration isolation pad has a stiffness value of k2. I add a spring with spring constant k2 in between the cantilever beam and the ground. I thought I can get a keq (k1*k2/(k1+k2)) and then find the new natural frequency or the system. But when I check it using ANSYS WB, I didn't get anything close to it.





RE: natural frequency for cantilever beam mounted on a vibration isolation pad
Have Fun!
James A. Pike
www.xl4sim.com
www.erieztechnologies.com
RE: natural frequency for cantilever beam mounted on a vibration isolation pad
RE: natural frequency for cantilever beam mounted on a vibration isolation pad
What is your goal? Check the FE model?
Have Fun!
James A. Pike
www.xl4sim.com
www.erieztechnologies.com
RE: natural frequency for cantilever beam mounted on a vibration isolation pad
in ANSYS WB, i just put a longitudinal spring at one end of the cantilever beam and the frequency changed significantly. when the beam was fixed on one end, the frequency was ~10Hz. with the spring, the frequency changed to 65Hz even though i varied the stiffness between 1e-11 lbf/in to 1e20 lbf/in. i was surprised that a spring can change the frequency that much and also even thought i varied the stiffness, it didn't have much effect. that's why i start to suspect that i probably didn't model the system correctly. don't know if you have any suggestions.
RE: natural frequency for cantilever beam mounted on a vibration isolation pad
Have Fun!
James A. Pike
www.xl4sim.com
www.erieztechnologies.com