How can I apply mass to a reference point on a shell structure?

[marenkr]

Hello everyone,

I have modelled 1/4 of a shell structure. I am doing a response analysis so I need to include the mass of the whole model.

Can I do this by adding a reference point to the shell structure? If so, is the location of the RP of great importance?
Do I need some kind of constraints to couple the structure to the reference point's mass, or is this done automatically. My structure is only one part. So I add the RP in the part module.

Many thanks in advance!

Best regards

Maren

 

[yuwimech]

You can just add a density property to the material that you assign for the model. You can do this in materials section.

OR you can add a force on that point instead. This way may come short but if only the force-effect at the superposition is needed this way may be suitable.

 

[marenkr]

Are you sure about that? I have applied a force on the structure (more presice a collison with another body) and I believe that an increase of the material density will influence the behaviour of the structure I have modelled.

I kind of want my increase in mass only to affect the global movement of the structure, and not the more local behaviour during loading. (sorry for my bad explanation).

You mean I can just add a force corresponding to my structural mass in the reference point? I don't need any types of coupling between structure and point? Is it possible to just apply mass instead?

 

[yuwimech]

you do want just the mass but not any moment any density or something. right?

I do not actually know the way of doing this. It's better someone more expert to answer your question. Best regards

 

[bassmanjax]

You can define a point mass (*ELEMENT, TYPE=MASS & *MASS) but you will have to connect it to your model. You can do this using *COUPLING.

Regards

Martin Stokes CEng MIMechE