cancel
Showing results for 
Search instead for 
Did you mean: 

Problems using Contact definition including offset

Valued Contributor
Valued Contributor

Hello,

 

I am currntly trying to set up a model with contact definition including a offset to consider a pressfit.

I already did the tutorial from the NX documentation. There everything works fine.

But in my actuall topic I still have a problem.

 

The offset is working so far along the contact definition, but at the ends of the contact surfaces the "corner" nodes are pulled together as if they where glued. See the picture.

 

I already tried to increase the contact surfaces, but the result was the same.

Does anybody has an idea how to solve this problem?

Picture of Contact definition_Tube over Schaft.pngContact pressure_Tube over shaft.png

 

Regards, 

Georg

 

3 REPLIES

Re: Problems using Contact definition including offset

Siemens Phenom Siemens Phenom
Siemens Phenom

Georg,

 

Are there coincident or shared nodes at the edges? The results image looks like they are shared, but your intent was to have them be coincident.

 

Regards,

Mark

Re: Problems using Contact definition including offset

Valued Contributor
Valued Contributor

Hello Mark,

 

I guess the problem is as you note. At the vertical connection plane below the tube edge I used a glue-coincident mesh mating condition.

For the contact area between the shaft and the tube i used the free coincident mesh mating condition, but somehow are the corner nodes of the tube connected to the "connection-plane-corner nodes" of the shaft and the same happens on the shaft end.

But i still don´t understand how this can occure.

 

Regards,

 

Georg

Re: Problems using Contact definition including offset

Siemens Phenom Siemens Phenom
Siemens Phenom

Georg,

 

I agree it doesn't make much sense. It could be dependent on the order of operations or a bug. I was able to reproduce your situation with these steps. My shaft and tube were both split into 2 bodies such that I had coincident faces in the contact region to start with.

 

1. Create glue coincident MMC between the shaft bodies

2. Create glue coincident MMC between the tube bodies

3. Create glue coincident MMC betweeen the contacting shaft and tube bodies

 

At this point everything is connected. I essentially made a mistake by defining the last MMC as glue coincident.

 

4. Edit the shaft/tube MMC to be free coincident

 

A check of the faces in the contact region shows that I have 2. A check of the edges in the contact region shows that I still have 1 edge where I expect 2. The edit of the MMC separated the faces, but the faces are using the same edges. It didn't produce new edges for the new face.

 

The workaround is to delete the MMCs that affect the contact faces/edges and re-create them with the proper MMC type. 

 

Regards,

Mark

 

Mark Lamping

Simulation Product Management

Product Engineering Software

 

Siemens Industry Sector

Siemens Product Lifecycle Management Software Inc.

mark.lamping@siemens.com