Error in simlab

Altair Forum User

Hello

I am getting an error like this. How to resolve this?

 *** ERROR # 772 ***
 It is invalid to use a free grid as an independent grid in RBE3 data.
 Free spiders are not allowed to be independent grids in RBE3 data.
                RBE3 id =   433592
           free grid id =   543806
    weighted components =      123
 You should remove this grid from the RBE3 data.
  
 *** Run terminated because of error(s) in the input data.
  

Rahul Rajan_21763

The error seems to be because of RBE3 nodes that are not connected to any part of the structure, this would create singularity in the model and hence OptiStruct throws the error message.
Automatic way to fix this via Param card, PARAM,RBE3FREE,YES.