Hi all,
I have been struggling with this problem for a couple of days now, and I still can't identify why it is not working as should.
I'm modeling a microvalve in a silicon MEMS structure. The idea is that the valve blocks the flow in one way.
The flow is induced by a pressure difference between the inlet and outlet. The pressure that the fluid exerts on the valve flap results in a deformation of the flap and the flap could make contact with the valve seat if the deformation is large enough.
I have a 3D model that all works fine; a fluid, a solid and a moving mesh to account for large deformations.
However, the contact pair that I have defined is always ignored by the solver. Please note that the solution that comsol finds yields no warnings or errors. It just does not take the contact pair into account, I think.
So what have I done to try to make this work:
- Source boundary is the most stiff part, destination boundary the least stiff.
- Played around with search distance for contact, also changed from "Fast" to "Direct" mode.
- Performed an parametric study increasing the pressure on the inlet, to make small steps in the deformation (200Pa per step, 200-2000 Pa sweep).
- Tried switching from "form union" to "from assembly"
- Read the comsol forum
- Studied the models in the model library
All without succes. Unfortunately this model is to big to attach, but it can be found here:
blackboard.tudelft.nl/bbcswebd..._contact_3um_gap%20%283%29.mph
I dont see any difference in the definition of the contact pair if I compare my model with the models in the model library.
However, what I noticed is that the solver does not mention any contact related variable under "dependent variables.
I also tried to remove the solver and initiate it again, but also without succes...
Can anyone point out what I'm missing, doing wrong, or something else that I should do?!
Any help would be greatly appreciated!
Thanks!
Diederik
I have been struggling with this problem for a couple of days now, and I still can't identify why it is not working as should.
I'm modeling a microvalve in a silicon MEMS structure. The idea is that the valve blocks the flow in one way.
The flow is induced by a pressure difference between the inlet and outlet. The pressure that the fluid exerts on the valve flap results in a deformation of the flap and the flap could make contact with the valve seat if the deformation is large enough.
I have a 3D model that all works fine; a fluid, a solid and a moving mesh to account for large deformations.
However, the contact pair that I have defined is always ignored by the solver. Please note that the solution that comsol finds yields no warnings or errors. It just does not take the contact pair into account, I think.
So what have I done to try to make this work:
- Source boundary is the most stiff part, destination boundary the least stiff.
- Played around with search distance for contact, also changed from "Fast" to "Direct" mode.
- Performed an parametric study increasing the pressure on the inlet, to make small steps in the deformation (200Pa per step, 200-2000 Pa sweep).
- Tried switching from "form union" to "from assembly"
- Read the comsol forum
- Studied the models in the model library
All without succes. Unfortunately this model is to big to attach, but it can be found here:
blackboard.tudelft.nl/bbcswebd..._contact_3um_gap%20%283%29.mph
I dont see any difference in the definition of the contact pair if I compare my model with the models in the model library.
However, what I noticed is that the solver does not mention any contact related variable under "dependent variables.
I also tried to remove the solver and initiate it again, but also without succes...
Can anyone point out what I'm missing, doing wrong, or something else that I should do?!
Any help would be greatly appreciated!
Thanks!
Diederik