Unrealistic Displacements in Frequency Studies?
Unrealistic Displacements in Frequency Studies?
(OP)
I'm doing frequency studies on a mass cantilevered/suspended by spring metal strips. I've been getting what appear to be reasonable frequency results, but grossly unrealistic URES Displacement values.
To do a sanity check, I've got a 4" long x 1" wide x 1/4" thick beam fixed to a vertical wall with a 2" cubic mass (approx. 2 pounds if steel material) merged off the free end of it. I've fixed the beam where the wall attachment would be and added a simple gravity load. When running a frequency study, the mode of interest is at about 59 Hz but is showing a resultant displacement of almost 5 inches.
I'm not familiar with this kind of result as my prior experience with frequency studies didn't reveal such unrealistic displacements. Can someone please explain this?
Thank you!
Tim
To do a sanity check, I've got a 4" long x 1" wide x 1/4" thick beam fixed to a vertical wall with a 2" cubic mass (approx. 2 pounds if steel material) merged off the free end of it. I've fixed the beam where the wall attachment would be and added a simple gravity load. When running a frequency study, the mode of interest is at about 59 Hz but is showing a resultant displacement of almost 5 inches.
I'm not familiar with this kind of result as my prior experience with frequency studies didn't reveal such unrealistic displacements. Can someone please explain this?
Thank you!
Tim






RE: Unrealistic Displacements in Frequency Studies?
Tata
RE: Unrealistic Displacements in Frequency Studies?
No matter which software you're using in MODAL STUDIES (FREQUENCY), the results are:
- When the models reachs its natural ressonance;
- How it would behave in ressonance;
So we have:
- WHEN: is the frequency (in rad/sec or Hz) resulta
- HOW: is the deformed plot
All other values are merely qualitative.
Best regards,
Eduardo
RE: Unrealistic Displacements in Frequency Studies?
The HOW is very usefull, use the displacement-result and let it animate, you'll see in which directions you can make your design stiffer..
RE: Unrealistic Displacements in Frequency Studies?
RE: Unrealistic Displacements in Frequency Studies?
Certified SolidWorks Professional
RE: Unrealistic Displacements in Frequency Studies?
If you want actual displacement, you'll need to run a linear dynamic study type.
RE: Unrealistic Displacements in Frequency Studies?
If you think about a modal analysis it is impossible to give real displacements because there is no load specified for the run.
TOP
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