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A question about Fixed boundaries

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Hi,

I am using Comsol v 3.5a and have a question about the behavior of fixed boundaries. Supposed I have a rectangle (2D) with lower boundary fixed, but the rest are free. The rectangle is compressed in the y-direction. Will the lower boundary still expand in the x-direction?

3 Replies Last Post Dec 22, 2010, 8:05 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Dec 21, 2010, 2:24 a.m. EST
Hi

no, you have no motion, fixed is u=0, v=0.

Check your equation you will see

You could use a "roller" which along a x direction line mean v=0 but u can take any value. But then you must retain one point along x otherwise you part might "roll" away. select a point in the centre, i.e. opposed to the overage Y load

--
Good luck
Ivar
Hi no, you have no motion, fixed is u=0, v=0. Check your equation you will see You could use a "roller" which along a x direction line mean v=0 but u can take any value. But then you must retain one point along x otherwise you part might "roll" away. select a point in the centre, i.e. opposed to the overage Y load -- Good luck Ivar

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Posted: 1 decade ago Dec 21, 2010, 6:46 p.m. EST
Thanks. One more clarification:

In terms of contact forces, would this fixed boundary act like a very rigid wall/floor?
Thanks. One more clarification: In terms of contact forces, would this fixed boundary act like a very rigid wall/floor?

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Dec 22, 2010, 8:05 a.m. EST
Hi

yes a fixed boundary is rigidly "stuck" so you can integrate the reaction forces (and moments if you define a reference point) to check your model loading coherence (with or without the Lagrange multipliers)

--
Good luck
Ivar
Hi yes a fixed boundary is rigidly "stuck" so you can integrate the reaction forces (and moments if you define a reference point) to check your model loading coherence (with or without the Lagrange multipliers) -- Good luck Ivar

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