how to define a solid non-deformable wall for impact analysis

Hi,

I am going to do a crash simulation with a non-deformable wall crashing a tube at a constant displacement deformation through Ls-Dyna solver. (please see the pic attached) The tube is going to be meshed with shell element using the mid-surface. The tube is constrained with 6 dof at the bottom.

What I know is if the wall is going to be meshed with solid element, it will show deformation from the simulation result. So how can I create a wall without any deformation but perform the constant displacement crash simulation?

Many thanks.

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Altair Forum User

Hi,

you can use a MAT RIGID for the Wall (or a Rigidwall, maybe). A rigid material, only x are free, looks like this...

*MAT_RIGID_TITLE
$HMNAME MATS       2MAT20_S355_Rigid_X_free
MAT20_S355_Rigid_X_free
         17.8500E-09 210000.0       0.3
       1.0         5         7
         0         0         0         0         0         0

For the velocity you can use a

*BOUNDARY_PRESCRIBED_MOTION

Regards,

Mario

Altair Forum User

Hi Mario,

Thank you for your reply. I will look into it.

I just got a mysterious issue that once I create a component collector from the model browser by right clicking to create, a property collector is also created automatically. But it didn't happen before. Please see attachment. For the outer_tube and Inner_tube in the graph, I have already deleted their property cards.

And another issue just comes along with the above one that I can not rename the midsurface I generated and the software gives me a messege: the collector specified does not exist in the model. Please see the attachment. But, again, I can rename any collector before.

Do you have any idea what causes this problem?

Many thanks for your help.

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Altair Forum User

Hi,

If you are creating a component by right clicking and create, then you can switch on or off the property / material creation into the specific tab (hook).

If you don't choose your own property / material, then empty collectors are created.

I can't understand (reconstruct) your second issue. Some reasons can be:

- you have choosen a existing name, then the renaming doesn't work

- check also if there hidden components (entitiy browser->components non active)

- reload your model and check the names

Regards,

Mario