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

Altair Forum User
Altair Forum User
Altair Employee
edited October 2020 in Community Q&A

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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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited July 2013

    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
    Altair Forum User
    Altair Employee
    edited July 2013

    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.

     

     

     

    <?xml version="1.0" encoding="UTF-8"?>post-7386-0-75745400-1374494872_thumb.jp

    <?xml version="1.0" encoding="UTF-8"?>post-7386-0-83968500-1374495208_thumb.jp

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited July 2013

    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

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