Altair RISE

A program to recognize and reward our most engaged community members

Nominate Yourself Now!

Error Regarding Circular Dependancy?

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.

Find more posts tagged with

English

OptiStruct

Accepted answers

All comments

Altair Forum User

Nayak,

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

Altair Forum User

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

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.