Error Regarding Circular Dependancy?

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

Hello friends,

 

I got this Kind of error:

*** ERROR # 179 ***
  The dependent d.o.f.s of multi-point constraints produces a singular matrix.
  This may be caused by a circular dependency in which a d.o.f. is
  indirectly dependent upon itself./n      MPC set id = 15398.
 

 

I have rbe2 element which constraint D.O.F 1 2 3 and Also MPC which used for incompatible contact. I have also checked Independent nodes from rbe2 and MPCs. Those don't have any Problems. How can I eliminate this error?

 

Please guide me.

 

Thank you.

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited January 2017

    Nayak,

     

    Check if dependent nodes are defined as independent node for other elements.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited January 2017

    As I mentioned, I am using MPC Converting from REB2, in which if my dependent node of Number 761027 is exactly same for MPC Dependend node.

     

    In case if I can convert it as in depended node then I will get another error as I have defined  MPC D.O.F for depended node more than Once. But here every things is okay. but still getting suspicious error. I just want to know that on the same node for contact nodes I have apply RBE2 for Rigid element and MPC for incompatible contact. Both at the same time is it possible or not?

     

    when I am only using thermal Analysis then I don't have any error. Error only Comes when I am using Mechanical and Thermal Both.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2017

    Hi Jay,

     

    In the sample file which you shared with me doesn't have any RBEs or MPCs. There is a RBE2 collector but no elements are there.

     

    Please cross check.

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