Showing results for 
Search instead for 
Do you mean 

Number of sliding contacts - convergence criteria

Hello everyone,


The convergence criteria for a SOL101 Linear analysis including contact is defined in the Connection Properties of the contact elements of the model.

With my version of Femap with NX Nastran two criterion are available :

  1. Number of contact changes
  2. Percentage of active contacts

Using the first criteria would lead to an output .f06 file with the following text :

1    LINA+                                                                APRIL   8, 2016  NX NASTRAN  5/ 5/15   PAGE   642
NUMBER OF CONTACT STATUS CHANGES:                4       (NCHG:            5)    
NUMBER OF INACTIVE CONTACTS:                  2784 
NUMBER OF STICKING CONTACTS:                  1593 
NUMBER OF SLIDING CONTACTS:                    375 

As you can see convergence is reached for this analysis because the number of contact changes between two contact loops is less than 5 (convergence criteria). This is good. However the number of sliding contacts is still quite high.


My point here is to discuss with you the reliability of the criteria Number of changes. Shouldn't the number of sliding contacts be taken into account when a static contact analysis is performed ?