Natural frequency of double acting hydraulic cylinder
Natural frequency of double acting hydraulic cylinder
(OP)
Hello,
I am trying to measure the natural frequency of double acting hydraulic cylinder analytically to validate numerical method. I have already done a basic modal analysis of each of the components( solid cylinders, and the barrel) on ABAQUS. But the analytical formula I saw was based on some experimental analysis which I don't have. SO, what I am asking is is there a way to find the nat freq without any experiments since I don't have the physical equipment (yet). If so, how?
Thanks a bunch,
Ann
I am trying to measure the natural frequency of double acting hydraulic cylinder analytically to validate numerical method. I have already done a basic modal analysis of each of the components( solid cylinders, and the barrel) on ABAQUS. But the analytical formula I saw was based on some experimental analysis which I don't have. SO, what I am asking is is there a way to find the nat freq without any experiments since I don't have the physical equipment (yet). If so, how?
Thanks a bunch,
Ann
RE: Natural frequency of double acting hydraulic cylinder
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Natural frequency of double acting hydraulic cylinder
RE: Natural frequency of double acting hydraulic cylinder
of course we need op to clarify wtf he meant.
=====================================
(2B)+(2B)' ?
RE: Natural frequency of double acting hydraulic cylinder
RE: Natural frequency of double acting hydraulic cylinder
I too thought the hydraulic column mode would be the one of interest, but I suppose a bending mode might be of interest too, for something like an aircraft landing gear exposed to a lateral shock load when it first contacts the ground...
RE: Natural frequency of double acting hydraulic cylinder
RE: Natural frequency of double acting hydraulic cylinder
RE: Natural frequency of double acting hydraulic cylinder
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Natural frequency of double acting hydraulic cylinder
RE: Natural frequency of double acting hydraulic cylinder
Thanks,
Anne
RE: Natural frequency of double acting hydraulic cylinder
I think you are looking for the transverse vibrations of the cylinder, correct? If so, then the vibration of the tube wall is probably not important to you. However, for transverse vibration analysis of the assembly a tube is probably a better (more realistic) choice than a solid hunk of metal.
Are you worried about the oil column natural frequency? It would produce vibration in the axial direction of the cylinder.
RE: Natural frequency of double acting hydraulic cylinder
Roughly speaking, define a mode shape as a function of time and some amplitude parameters, say .5, 1.5,2.5 wavelengths of a sin wave for bending. Then work out the potential+elastic energy at maximum deflection, and the KE at zero deflection. These are equal, with velocity= w.x, now differentiate w with respect to the amplitudes of the sin waves, and aim for minimising w. It takes a bit of practice, but is very powerful for simple but non uniform systems.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?