Learning Forum

[Roxas Hunter]

Hello Everybody,

 

I'm trying to simulate the gasket behavior between two flanges after the bolt preload.

The gasket is made in steel 1010 1/4 hard , the stiffness behavior is setted as flexible body not as gasket, both contact surfaces are made in aluminum.

I run the analysis with the mesh size of 2mm for both contact surfaces and 1mm for the gasket, everything has worked so far and the results look fine.

I would like to get finer contact pressure results, so I changed the mesh size and the model no longer converges... I tried different things but none of these  helped me to converge.

Any ideas to help me?

Thanks in advance for your support!

 

[Ankush Choudhary]

Hi Roxas,

Could you please try  reducing the Normal stiffness factor (FKN) value?

[Roxas Hunter]

Hello Ankush,

Thanks for the advice.

I switched the normal stiffnes factor for both gasket contact from "program controlled" to factor and the value is 1

Still not converged... Should i try another value?

Thanks in advance for your support!

[pawel_rek]

Normal Stiffness Factor = 1 is basically default (what ANSYS calculates). Try reducing it to 0.1 and check convergence. Depending on a mesh quality try also different "Detection Methods". If you're using newer ANSYS release you can also play a bit with "Normal Lagrange" formulation. Hope it helps. 

[Roxas Hunter]

 

 

Hello pawel_rek, thanks for the advice now it converge but I can’t no longer see the contract pressure between the bot face of the flange and the top face of the gasket… I see this:

 

 

I tried even with normal Lagrange formulation but it doesn’t converge.