Learning Forum

[Doug]

Hello everybody
I am a beginner in Ansys simulation and I need your help to solve a model with high penetration.
As can be seen below, I have successfully simulated the first model with low penetration / gap. The mesh was optimized, a non-linear contact was defined (frictionless).

 

 

 

   

 

Now I want to simulate anothermodel with higher gap , under the same conditions as before.  

 

* First increased the number of substeps but that didn't work

 

* Then I reduced the mesh size, but that didn't work.

   

 

* Then I used a force to reduce the Initial gap size before contact was made, but that didn't work.  

* Then I used displacement to reduce the gap size, but that didn't work either.    

Please Note that I can't change any Stifness option to solve the convergence problem, because the result has to be symmetrical.

I know I'm missing something, but I don't know exactly what.
I would be happy to help you solve this problem and have a happy Christmas.

 

[parkersheaffer]

If you have an initial gap i would just remodel the geometry, as you only have two bodies this should be fairly quick to do. Reducing element size on the cylinder contact face might help as well.

One other thing that is typically useful is making sure your contacts are working as intended, right click the connections folder and insert a contact tool.  

[Doug]

Hello Parker,

thank you for your reply!

1. The geometries are information that I must not Change.

2. Reducing element size on the Cylinder: I'm not sure if that can help but i still try

3. i already create a contact tool as you can see below

 

 

[parkersheaffer]

So let me start from the beginning as I think I misread your model setup. You are creating geometry with an initial gap, the end result you want is to be in contact with the inner face of the cylinder.

 

[Doug]

exactly

 

[Doug]

and i just reduced the element size on the cylinder and it always does'nt work.
 
 

[parkersheaffer]

Can you post the solver output file.

[Doug]

how can i do it please?

 

[parkersheaffer]

Right click solution and look for a file called "solve.out". Should be able to open it with notepad.

[peteroznewman]

Hi Doug, You can try to make this a 3-step analysis. I recommend you put at least 2 elements through the thickness of the ring.

Under Analysis Settings, type 3 for Number of Steps.  I assume Large Deflection is already On.

Right mouse click on Static Structural and Insert a Contact Step Control into the model. You are going to deactivate the contact in Step 1.

Insert a Displacement on the end face of the ring you want to put inside the tube. The displacement in step 1 is to move that face to be perpendicular to the tube, so the contacting face is tangent to the tube.

Insert a Moment load on the other end face of the ring.  You should play around with the magnitude of the load until the result at the end of step 1 is that the ring is deformed enough to be inside the tube.

In Step 2 you activate the contact.

In Step 3 you deactivate the moment and the displacement on the two ends of the ring.

The result should be the ring is inside the tube held by the contact with nothing applied to the ends.

In Step 3 (and maybe step 1) might want Auto Time Stepping On with Initial, Minimum and Maximum Substeps set to 100.

If this doesn't work, you can break Step 3 into 3 and 4 and deactivate the BC on each end of the ring separately.