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3.5a> Struct. Mech.> Circular, Frictional Sliding Constraint
Posted Aug 20, 2010, 12:30 a.m. EDT Structural Mechanics Version 4.2 2 Replies
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Hello,
Suppose I have a large metal plate with a large circular hole drilled into it.
Now I spread a thin, flexible sheet above this metal plate, and push inward through the hole.
The sheet will displace through the circular hole and down below, and its motion will be confined to the circular constraint of the structure of the hole. There also will be frictional effects.
How can I model this with COMSOL? Can I do it with 3.5a, and if so, which physics application(s) should I use?
Basically, most important is learning how to specify this circular constraint, and of less importance is the frictional force specifications.
Thank you.
Best regards,
Kevin
Suppose I have a large metal plate with a large circular hole drilled into it.
Now I spread a thin, flexible sheet above this metal plate, and push inward through the hole.
The sheet will displace through the circular hole and down below, and its motion will be confined to the circular constraint of the structure of the hole. There also will be frictional effects.
How can I model this with COMSOL? Can I do it with 3.5a, and if so, which physics application(s) should I use?
Basically, most important is learning how to specify this circular constraint, and of less importance is the frictional force specifications.
Thank you.
Best regards,
Kevin
2 Replies Last Post Aug 22, 2011, 1:00 p.m. EDT
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Posted:
1 decade ago
Hi
I believe your model there should be considered as "difficult" (but anycase interesting and challenging)
friction along and edge is difficult to assess because of the stress and pressure concentration effects (singularities), but on two sliding surfaces (assembly mode) you can define pressure and friction forces.
Your next challenge would be the topology, if your membrane is very flexible and stretches I believe you can get further, if its rather stiff you would expect it to buckle along the rim as the excessive surface is forced through the hole, this is really a highly non-linear bahaviour, tricky, not sure how solve that.
In anycase, I would suggest to start in 2D axi to test the model and the physics
--
Good luck
Ivar
I believe your model there should be considered as "difficult" (but anycase interesting and challenging)
friction along and edge is difficult to assess because of the stress and pressure concentration effects (singularities), but on two sliding surfaces (assembly mode) you can define pressure and friction forces.
Your next challenge would be the topology, if your membrane is very flexible and stretches I believe you can get further, if its rather stiff you would expect it to buckle along the rim as the excessive surface is forced through the hole, this is really a highly non-linear bahaviour, tricky, not sure how solve that.
In anycase, I would suggest to start in 2D axi to test the model and the physics
--
Good luck
Ivar
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Posted:
1 decade ago
Hi both of you,
I have two questions with respect to this discussion,
1- When I have a glass sphere pushing against a hyperelastic film, do I need to consider friction? I mean what is the indication that here, in this problem I need friction? My particle moves from 2 micrometeraway from the surface and presses the film for 300 nm.
I am learned from tutorials that In geometry, when I have 2 objects like a glass sphere and a hyperelastic film, when I want to finalize everything, I will choose make an assembly and not form a union. What is the difference between these two things? When are things union and when assembly?
yours
Marjan
I have two questions with respect to this discussion,
1- When I have a glass sphere pushing against a hyperelastic film, do I need to consider friction? I mean what is the indication that here, in this problem I need friction? My particle moves from 2 micrometeraway from the surface and presses the film for 300 nm.
I am learned from tutorials that In geometry, when I have 2 objects like a glass sphere and a hyperelastic film, when I want to finalize everything, I will choose make an assembly and not form a union. What is the difference between these two things? When are things union and when assembly?
yours
Marjan