[ABAQUS] Huge number of natural frequencies issue (70eigenmodes/2Hz ca.). Any hints?

[omar.el92]

Hi everyone.

I'm performing a natural frequency extraction of a railway, in order to get its eigenmodes in the range 0-1200Hz.
However, while performing the Frequency step needed for the frequency extraction, ABAQUS computes an enormous amount of natural frequencies, ca. 70 for a 2Hz frequency range.
Anybody could give me some hints about how to overcome this issue and get an acceptable frequency analysis? 

Regards,
Omar

 

[IceBreakerSours]

I would check if the model is un/underconstrained, especially if the frequencies are close to zero.

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[Mustaine3]

When you have a mesh with linear hex elements, it could be hourglassing. Try with reduced integrated parabolic hex and compare the results.