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Pull off contact - electrostatic actuated beam
Posted Apr 25, 2011, 9:41 a.m. EDT Structural Mechanics 4 Replies
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Hi,
I've been working on a CNT pull-in and pull-out voltage. One of my goals is to check the stiction phenomena occuring when the beam is being apparted from the substrate. I want to make a 2-step simulation. During the first step I crush the beam against the substrate and during the second one I add a force in the upward direction.
I checked the cilinder contact example model and I'd like to know if anybody has ever taken off the cilinder and check the stresses.
Thank you,
David Carvajal
I've been working on a CNT pull-in and pull-out voltage. One of my goals is to check the stiction phenomena occuring when the beam is being apparted from the substrate. I want to make a 2-step simulation. During the first step I crush the beam against the substrate and during the second one I add a force in the upward direction.
I checked the cilinder contact example model and I'd like to know if anybody has ever taken off the cilinder and check the stresses.
Thank you,
David Carvajal
4 Replies Last Post Apr 26, 2011, 1:41 a.m. EDT
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Posted:
1 decade ago
Hi
what physical phenomena in COMSOL will give you some stiction ? I'm not sure there is any, by default so you must probably define something yourself.
Another point, passing the pull in value is tricky for the solver. Its easier to use pressure to make the contact, as this is linear
--
Good luck
Ivar
what physical phenomena in COMSOL will give you some stiction ? I'm not sure there is any, by default so you must probably define something yourself.
Another point, passing the pull in value is tricky for the solver. Its easier to use pressure to make the contact, as this is linear
--
Good luck
Ivar
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Posted:
1 decade ago
If by stiction you mean a static coefficient of friction that is higher than the dynamic coefficient then the COMSOL friction input already supports that feature. It should work for the cylinder example you mentioned.
Nagi Elabbasi
Veryst Engineering
Nagi Elabbasi
Veryst Engineering
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Posted:
1 decade ago
Hi
indeed, if we work tangentially, if we pull normally as a cantilever in contact will do, I'm not sure that is enough. In MEMS devices there are also van der Walls forces and other phenomena acting too
--
Good luck
Ivar
indeed, if we work tangentially, if we pull normally as a cantilever in contact will do, I'm not sure that is enough. In MEMS devices there are also van der Walls forces and other phenomena acting too
--
Good luck
Ivar
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Posted:
1 decade ago
Hi,
thanks for your reply. Actually I'm trying to figure out how can I make it work but I do have a couple of issues. In first place when I apply an upwards mechanical load the beam does not deattach from the substrate. I tried to use the static friction feature in the contact pair but the solver does not work. If I try to use an initial pressure it does not work either. I'm attaching my model.
Thanks for your help!
greetings
thanks for your reply. Actually I'm trying to figure out how can I make it work but I do have a couple of issues. In first place when I apply an upwards mechanical load the beam does not deattach from the substrate. I tried to use the static friction feature in the contact pair but the solver does not work. If I try to use an initial pressure it does not work either. I'm attaching my model.
Thanks for your help!
greetings