Does not add load to mass in frequency analysis

Question

Does not add load to mass in frequency analysis

sal21 (Student)

(OP)

12 Feb 24 14:29

Hi,
I will do frequency analysis on abaqus, but I have external loads. I define these before the frequency as static general Nonlinear on. I cannot see its effect on the mass. Loads are not included in the mass. How can I include loads in the total mass?
Thank you.

FEA way (Mechanical) · Answer 1 · 2024-02-12 17:08:08

Preloads affect natural frequencies but not through a significant change in mass - it's because of stress stiffening/softening effects.

sal21 (Student) · Answer 2 · 2024-02-12 20:09:24

RE: Does not add load to mass in frequency analysis

sal21 (Student)

(OP)

12 Feb 24 20:09

Thank you for your return.

GregLocock (Automotive) · Answer 3 · 2024-02-12 20:28:01

...which in a linear system, assuming small displacements, still has no effect on the resonant frequencies.

Cheers

Greg Locock

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FEA way (Mechanical) · Answer 4 · 2024-02-12 20:41:21

We are talking about preloaded modal analyses here - those that are preceded by a nonlinear static analysis and then the stress stiffening/softening effects can be considered during the natural frequency extraction.

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Does not add load to mass in frequency analysis