Displacement in forced vibration

[unc25]

Hello all,
This is my first post here and I am hoping that someone would help me out.

I would like to get the displacement at the point of interest. Here is how I have carried out the forced vibration simulation: After an "initial step", I chose "Linear Perturbation" to first extract the natural frequency. My next step was "Modal Dynamics". I then applied the load in the form of a sine wave under the same step. I have an isotropic material. When I try to submit the job, I received following warning:

"A steady state subspace projection based, or mode based dynamic analysis is required for a model with non-diagonal mass matrix. Abaqus/standard subspace projection based or modal based dynamic analysis for a model with non-diagonal mass matrix (e.g. using substructure) might give incorrect reaction forces. However other output quantities will be correct."

I am unaware of how severe this warning is. Can anyone please guide me regarding this? Have I selected the correct approach for the forced vibrational analysis?

Thanks a lot!


Mandar

 

[caemagic]

Hi Mandar

In vibration simulation , almost any software would require you to carryout a modal analysis first , hence u should extract the eigenvalues of the ur structure first , then proceed to any other analysis including transient analysis , hope that helped

caemagic

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