Showing results for 
Search instead for 
Did you mean: 

Work with contacts in mechanism


Hi to everyone!

I'm trying to model a roller bearing loaded on the external ring, i've never used femap for a complex model, now i'm stuck and i can't see any solution.

The most important problem is the contact between the external ring and the rolling elements, when i try to apply the contact, only the side faces of the bearing and the shaft are connected while the rolling elements are not connected to the external ring. Another thing that i can only resolv by flagging the bailout option, is the error occurred when i run nastran saying that i'm working with a mechanism, is there any other way out to this problem?maby apply other constraints? Thanks in advance to everyone! 



Re: Work with contacts in mechanism

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Dear Marzatico,

The meshing approach will depend if your target is to study the roller bearing (you are a manufacturer of roller bearings) or you are utilizing commercial roller bearings in your structure.


If you need to model in detail the contact between rolling elements and bearing body then I suggest to take advance of SYMMETRY, this will stabilize your model against rotation.


Also take a look to my blog in the following address where you will understand how to use the important contact INIPENE parameter:


INIPENE contact parameter


If you want to model the bearing support including the effect (both damping & stiffness) of the bearing in the assembly, then use a CBUSH element, this is one of the most powerful elements of NX NASTRAN:




Best regards,


Blas Molero Hidalgo, Ingeniero Industrial, Director
Blog Femap-NX Nastran:

Re: Work with contacts in mechanism



Dear Blas,


first of all, thanks for your articulated answer, i've applied the symetry constraint and also changed the contact property, but now the rolls are pushed out axially even if the are constrained in that direction, what can i do? thanks in advance!