Help with MPC

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

Hi, I'm modeling a joint between a beam element and a rigid element. For this I used the MPC to connect the beam end and the rigid center node, in order to use this connection in different loadsteps. But the behavior of the nodes on the results is like they are disconnected.

 

Is there another way to simulate this?

 

All help is greatelly appreciated.

 

Thanks!

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited March 2014

    Hello,

     

    try to connect the Rigid (RBE2 or RBE3 ?) directly to the beam. Check the DOFs.

    I think it is not a good idea to connect rigids with MPCs.

     

    Regards,

    Mario

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2014

    Hello,

    I have the same problem as KaTo_SRT.

    The sense of using an MPC at this joint is that one can choose if the MPC is activated or not, for every loadstep independently. In this way you can choose in every loadstep if there is a connection or not.

     

    But in my case it doesn't work. The MPCs are not the way to solve this problem.

     

    Generally I'm searching for a rigid connection, which I can activate or not in different loadsteps. How to solve this problem?

     

    Regards,

    Keule

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2014

    Hello,

    with the help from the support hotline, I solved the problem.

    To connect two nodes with MPCs, there has to be one equation for each dof you whish to have a connection for. To create a connection which behaves like an RBE2-element there have to be 6 equations, one for every dof. The key is the weight factor: when creating the connection mentioned above the weight factor of one node has to be -1 while the weight factor of the other node has to be +1.

    Regards,

    Keule

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