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Conditional Displacement?

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Is it possible to incorporate a conditional displacement constraint into a model?

For example, if a pressure load is applied along a cantilever beam and I want it to be able to freely displace until a certain height (as if there was an imaginary wall at that height), can I model this?

If H is the critical height then the logic would be:

Free to move when 0<Height<H
Displacement = 0 when Height>H

Thanks,

Daniel

1 Reply Last Post Feb 23, 2012, 4:07 p.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Feb 23, 2012, 4:07 p.m. EST
Hi

hear like a contact type case, or just a prescribed displacement case.

But if you want to apply a force until a point reaches a given height, you can apply a load of a value MyF (along the correct coordinate, lets say "y") then add a Global equation where you define MyF such that intop1(v)-V0 (or intop1(y)-Y0 ) = 0 where intop1() is a Definitions point integration of the given point "#p" you vant to track, and "v" is the dependent variable for the displacement along "y", V0 is the maximum displacement you want your point to do (or y is the spatial coordinate of your point, and Y0 is the maximum value along y of your point. Note: you might need to turn ON the solver geometrical non-linerity for this second case as this handling of internal frame values have changed in v4.2a, be aware and pls check)

--
Good luck
Ivar
Hi hear like a contact type case, or just a prescribed displacement case. But if you want to apply a force until a point reaches a given height, you can apply a load of a value MyF (along the correct coordinate, lets say "y") then add a Global equation where you define MyF such that intop1(v)-V0 (or intop1(y)-Y0 ) = 0 where intop1() is a Definitions point integration of the given point "#p" you vant to track, and "v" is the dependent variable for the displacement along "y", V0 is the maximum displacement you want your point to do (or y is the spatial coordinate of your point, and Y0 is the maximum value along y of your point. Note: you might need to turn ON the solver geometrical non-linerity for this second case as this handling of internal frame values have changed in v4.2a, be aware and pls check) -- Good luck Ivar

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