# Cooling Brake Simulation: A Motion Problem Between Two Solid Interfaces

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May 11, 2020, 06:50
Cooling Brake Simulation: A Motion Problem Between Two Solid Interfaces
#1
New Member

Onur
Join Date: Dec 2018
Location: Turkey
Posts: 25
Rep Power: 6
Hello there people of the internet;

Recently I have started a project on F1 Car brake simulation. The geometry can be seen below. The red/orange color represents the air domain (the inlet and pressure outlets respectively) while those two things to the right of the main body, which is the disc, are the calipers that will apply friction the the disc.

The continua for the solids are:
FSI-Fluid Structure Interaction
Finite Element Solid Energy
Solid Stress

The fluid, on the other hand, has coupled energy and flow is turbulent and constant density. So far no errors given on the models.

The disc in the middle will be rotating at 2000 RPM while the calipers will apply pressure gradually slowing down the rotation; however, I cannot assign different motions to the calipers and the disc. (I assigned the same rotational motion to the fluid not sure if necessary) The error can be seen below. Apparently both systems must be in the same motion yet that's something I do not want.

My interfaces are all mapped-contact interfaces created by imprinting and making contact mode interfaces. Not exactly sure what I should be doing.

That being said, do I need to assign rotation to the fluid region or can I leave it be with the mapped interface?

Attached Images
 Brake Geometry.jpg (22.5 KB, 15 views) Error.png (34.3 KB, 11 views)

 May 26, 2020, 05:32 #2 Senior Member   Ping Join Date: Mar 2009 Posts: 556 Rep Power: 18 do you still need help in this - i see its old?

 May 26, 2020, 20:37 #3 New Member     Onur Join Date: Dec 2018 Location: Turkey Posts: 25 Rep Power: 6 Yes indeed! Instead of applying a friction/motion I just calculated the energy produced by the braking action and put the value as heat generation.However, it would be nice to know how to do it the motion way. I did some reading perhaps creating a baffle interface helps? Thank you

 May 27, 2020, 09:20 #4 Senior Member   Ping Join Date: Mar 2009 Posts: 556 Rep Power: 18 i am not that familiar with the fe solver and its limitation in star but on a quick read of the first help page it says there can only be small sliding frictionless motion between solids so it looks like the fe approach is out. so i would be using the fv solver on the solids for just temperature prediction and the fixed brake pad will be allowed while the air and the disk rotate (both must) and you set heat transfer between the air and metal and metal to metal and can add the required heat source at the friction boundary. if doing at a fixed speed it could be done as a steady state case using the moving reference frame technique and a mixing type interface between the solids to distribute the heat around the disk. if you need the stress and strain predicted in the disk then you could map the temperature field from the fv solution into an fe case of just the disk as the initial condition, or maybe try using the fv stress solver which might be okay on these more solid parts.

 May 28, 2020, 08:24 #5 New Member     Onur Join Date: Dec 2018 Location: Turkey Posts: 25 Rep Power: 6 It seems logical to eliminate FE solver since I did try sliding frictionless motion in the interfaces which still gave the error. I'll apply the FV solver and see what happens. Thank you!

 Tags brake cooling, fsi, mapped interface, motion, solid motion