How to extract Acceleration response about CG of a model in ABAQUS? 1

[nama21cha]

thread799-341184
Hi,
I want to extract acceleration response of the model at its CG which has gone under time history analysis. I have used frequency extraction step followed by dynamic implicit step. I have attached a simplified diagram which represents my model.

I can extract the response on the nodes within the model. But the location of CG falls in hollow section of the model.

Thanks

Nama

 

[FEA way]

Create a reference point at that location and connect it with the rest of the model using rigid body constraint or other available constraint type. You may have to assign small mass/inertia to this point to avoid errors.

 

[nama21cha]

Hi FEA way,
Thanks for your recommendation. I guess, it's solved now.

Steps I used:
1)Create a Reference Point at the location of CG.
2)Create Constraint
3)Constraint Type: Coupling, MPC ( TIE, Link, Beam etc ) & Rigid Body.

While doing a lot of hit & trials, I found MPC TIE is suitable one. Because, there is no change in the frequency of the model compared with model prior to assignment of this constraint. While other options presented significant frequency change during Frequency extraction process.

Is there any another way to validate?

Cheers,
Nama

 

[FEA way]

If dynamic response of the structure is the same as before the application of the constraint then this approach seems correct.

 

[nama21cha]

Agreed!