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ELMER GUI - Modal Analysis

Posted: 08 Nov 2017, 13:15
by FemUser1414
Hello fellow Users

I am new to Elmer-Gui and Forums in general. So I do appreciate the support and the patience.

I am trying to complete a modal analysis of a simple square section bar (SIF attached): 10mm x 10mm x 100mm - Generic Steel Alloy - Free-Free.

Comparing the results of this model with hand calculations (Formulas for natural frequency and mode shape - Blevins) highlights "large" discrepancies (screen shot of spreadsheet attached)!

Am I doing something wrong?
I don't believe the deviations are related to mesh refinement (exercise has been completed but results are not attached).
I don't believe the deviations are related to the specific solver (exercise has been completed but results are not attached).

Please help.

Regards
FemUser1414
PS. I am not worried about the first 6 modes as predicted by Elmer because they are rigid-body modes.
PS. Additional information:
This exercise is just to get me familiar with this package. I am planing to use Elmer-Gui for a more elaborate application: Harmonic Analysis of a pre-stressed cylindrical object. This object is pre-stressed due to shrink-fit onto a more stiff and heavier part (not sure that I want to do Contact Analysis at this stage! Maybe after investigating the initial results)