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January 25, 2024 at 8:48 pmdxiangSubscriber
Hello,
I am trying to model isolators with joint and two questions here:
1, how to deifne siffness if compression and tension are different. (such as wire rope isolator);
2. Can I define damping ratio in joint? Or Is there any way to tranfer damping ratio to vicous damping.
Thank you
Daniel
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January 29, 2024 at 4:34 pmdloomanAnsys Employee
Instead of a joint consider using a nonlinear spring (COMBIN39.) The nonlinear spring has a material property DMPR, which is short for damping ratio. Â
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January 29, 2024 at 11:41 pmdxiangSubscriber
Hi Dave,
Thank you for quick response. Further quesitons:
1, I have to use 3 springs for each isolator, right?
2. Can I make dynamics analysis such as modal, random vibration and transient if nonlinear spring is used?
Thanks
Daniel
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January 30, 2024 at 5:08 pmdloomanAnsys Employee
Yes, you need 3 springs if you want to specify the lateral stiffnesses of the isolator. If the spring stiffness is not the same in tension and compression then linear analyses like modal and random vibration are not possible. A full transient (not mode-sup) is possible with non-linearities.
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January 31, 2024 at 5:21 pm
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January 31, 2024 at 7:09 pmdloomanAnsys Employee
In a harmonic analysis you could specify a stiffness equal to LOAD/20 mil) for the frequency you are solving for, but in general, no, you can't specify isolator properties as a function of frequency. The LOAD is probably a combination of damping and stiffness forces so that makes it even more ambiguous how to use these curves.
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February 1, 2024 at 11:47 pmdxiangSubscriber
Get it. About joints, can I probe them in postprocess? I defined the isolators as general joint with X,Y,Z free plus proper stiffness. After SRS simulaiton, I want to to check axial and radical inforamtion such as deflection, force etc. But I can not see joint in probe drop menu. Or there is any other way?
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February 2, 2024 at 1:58 pmdloomanAnsys Employee
If it's possible you will be able to drag and drop the joints onto Solution (highlighted in your image.)Â If you're not allowed to drop them on Solution then no.
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February 2, 2024 at 6:40 pmdxiangSubscriber
It works in static analysis, but not for spectrum response. I am working on a product design, which is under shock load. Not sure if you have APDL script which can get joint (isolator) information after SRS simulation.Â
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- The topic ‘question about define joint in dynamics analysis with ANSYS mech’ is closed to new replies.
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