PINBALL REGION ON CONTA 172

[richardforever]

Hello people,
I just want that anyone could answer a query that I have with contact elements.
I'm modelling a thermal grease sticked to another two metals (silicon and copper) with conta 172 an targe 169 elements
The thickness of the grease is 0.02 mm but I want to introduce this grease with contact elements. I have done manual calculations and my TCC parameter = 5 . Now my doubt is about PINBALL region . I know that is like a 2D circle that surrounds the contact element and if I increase pinball region the target and contact surface 'see' each other. Does it mean that i have to put a high numbre of pinball region? (1000 is good or too high?). Of what magnitude? Apart of this is anything else that I have to take into account like (FKN, ICONT). Thanks!

If anyone could explain this parameters i would be very pleased. Thanks!

 

[rickfischer51]

The pinball region is an area of awareness for numerical computation. If a target element is outside the pinball region of a contact element, the software does not do a penalty calculation. this is done to save time. if the two bodies move closer together and the target is in the pinball, then it does a calculation for that element. You are using bonded contact. The bodies will not change position, so you do not need a large pinball. The programm calculated default should be fine.

Not sure exactly what you are doing, but if you are modeling a 0.02 mm gap between your bodies, you are misapplying the thermal conductance feature. It has no thickness. look at the units. They are W/mm2-C, same as convection. The intention is that you model the parts touching, stick them together with bonded contact, and put in heat transfer that is proportional to the surface area in contact. If you model the gap, make sure the pinball is larger than the gap, or the surfaces will not see each other. I've never done this so I could be wrong, but if you do this, I believe that changing the gap should have no effect on your results.

Rick Fischer
Principal Engineer
Argonne National Laboratory

 

[richardforever]

Thank you very much. It's been a great help.
My actual model hasn't got thickness. I was just comparing the solution with another model with thickness and a predefined area. Anyway the doubts has been resolved
Besides, it is true what you said that changing the gap hasn't got any effect.