Interface type to be given

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

Hi,

 

I have to give a interface between a surface and a block. The block is on the surface . Initial velocity is given to the block. Can you suggest what Interface type has to be used between block and the surface?

 

Thanks in advance.

 

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2016

    Hi Raghav,

    You can try modeling this contact using TYPE2 tied interface that kinematically connects a set of slave nodes to a master surface.

    Please visit this link which give more details on Type 2 interface: http://www.altairuniversity.com/learning-library/vii_b_interface-type-2-in-radioss/

     

  • gopal_rathore
    gopal_rathore Altair Community Member
    edited October 2016

    Hi Raghav,

    It seems that you want to study the motion of the block over a fixed surface. For this you can go for using TYPE 7 interface with friction value if required between surface and the block. Are you using RBODY for block and giving imposed velocity to master node RBODY?

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2016

    Hi Gopal,

     

    Yes I'm using RBODY amd IMPACC actually for the block. I guess Type 2 interface is not suitable as well because it is typically used as tied interface(for eg spot welds). I am using type 7 interface. Also when I run my job. It's showing 0 errors however the output file is not getting generated. Only the restart files are generated...

     

    What could be problem??

     

     

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2016

    Hi Raghav,

    Check the time step of the model. If possible please share the model files (_0000.rad and _0001.rad) for better understanding.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2016

    /VERS/130
    /RUN/1910/0/
    0.120000000000000   
    /ANIM/ELEM/EPSP
    /ANIM/ELEM/VONM
    /ANIM/MASS
    /ANIM/DT
    0.000000000000000    1.00000000000000E-03
    /TFILE/0         
    1.00000000000000E-03
    /ANIM/NODA/DT
    /ANIM/NODA/DMAS
    /ANIM/NODA/DINER
    /DT/BRICK/CST
    0.670000000000000    4.00000000000000E-07
    /DT/INTER/DEL
    0.670000000000000    5.00000000000000E-07
    /DT/NODA/CST/0
    0.670000000000000    5.00000000000000E-07

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2016

    The units for time is in seconds.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2016

    Hi Raghav,

    In the engine file provided in the above post, the scale factor for imposing a time step is 0.9.

     

    /DT/NODA/CST

    0.9 5E-7

    Please clarify the same for all.

    For a workaround please share your model file (_0000.rad) through the dropbox link provided in the signature. Also please attach the starter out file (_0000.out)

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2016

    Hi,

     

    Thnaks for the advice.. I decreased the time step and its working. However if in the animation The base nodes of the blocks are getting attached to the surface. Could you specify why??

     I used a type 2 interface between cube and surface, pulse is given to the center node of the cube(made it RBODY). and the surface is stationery.

     

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2016

    Hi Raghav,

    For better understanding need to review the model.Meanwhile can you try running the analysis with Type 7 interface and update.

  • gopal_rathore
    gopal_rathore Altair Community Member
    edited October 2016

    Hi Kash,

    TYPE 2 is a tied interface and thus will not allow relative motion. TYPE 7 is a general contact which will take sliding if happening into account. So, go for TYPE 7 contact between the surfaces and also friction value if available.

    Also for time step first run the model with no imposed time step option i.e DT/NODA commands , with this you will be able to know the natural time step and based on that value imposed time step is defined. If you have already done this, ignore this.

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