Multi point Constraint

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

Hi,

 

 

 

Can anyone please explain to me what is the use of this function :  menu Load Case> Multi point Constraint ?

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited November 2014

    Hi Youssef,

     

    MPC are used to define a relationship between a set of nodes to dependent node (Equation).

     

    For instance, you have a dependent node and you want the X displacement of the dependent node equal to sum of half of X displacement of one of the independent node and twice of Y displacement of another independent node.

     

    in such a case you can use MPC.

  • Rahul_P1
    Rahul_P1
    Altair Employee
    edited November 2014

    Perhaps this webinar on MPC will help, - http://www.altairhyperworks.de/html/de-DE/BestPractice_Recordings/2011/07_May13_Radioss_RBEs_MPCs_index.html

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited November 2014

    Thank you Rahul , Thank you Prakash  image/emoticons/default_smile.png' alt=':)' srcset='/emoticons/smile@2x.png 2x' width='20' height='20'>

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited November 2014

    Hi,

    I have a also question about MPC.

    How do I create MPC's in HyperMesh for the RADIOSS Solver?

     

    F.M.

  • Simon Križnik
    Simon Križnik Altair Community Member
    edited January 2018

    Hi,

     

    I would also like to know how to create MPC in Radioss user profile to model cyclic symmetry.

     

    An example using this type of kinematic constraint would be appreciated. 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited January 2018

    Hi Ivan,

    For cyclic symmetry in RADIOSS we have a workaround.

    Select the nodes where you apply the boundary conditions, and put imposed displacement (/IMPDISP, and keep icoor=1)load on those nodes with zero magnitude function  in the required directions. 

    X       Y

    0       0

    1       0

     

  • Simon Križnik
    Simon Križnik Altair Community Member
    edited January 2018

    Thank you for the tip, however I am unable to properly apply this workaround. The reason is this model probably needs node to node constraints like MPC. Could you please look into the files?

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited January 2018

    Hi Ivan,

    Reviewed your files.

    The model is not a cyclical symmetry case but a planar symmetry problem. There are some limitations in RADIOSS if you want to continue with planar symmetry.

    If your purpose is only to reduce the run time I would recommend you to change the function defined for /IMPDISP load.  That is, instead of ramping the load in 1s you can ramp in 200 or 300ms and run the model for the same time.

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