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How to support flexible tube.

Posted Mar 20, 2014, 3:24 p.m. EDT Fluid & Heat, Computational Fluid Dynamics (CFD), Geometry, Structural Mechanics Version 4.4 2 Replies

Barrett Hutto
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Hi-

I am doing a 3D FSI model on a simple branched artery with blood flow. I naturally want the artery to expand and contract as the fluid moves though. What is the best way to constrain the inlets / outlets? Rollers do not add enough constraint and fixed edges constrict the artery from expanding / contracting. In addition, I get high stresses at the areas of constraint.

Attached is a picture of the geometry where the arrows are the fluid flow

Thanks,
Barrett
2 Replies Last Post Mar 21, 2014, 11:37 p.m. EDT
Barrett Hutto
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Posted: 1 decade ago Mar 21, 2014, 11:14 a.m. EDT
Attached is the picture of the geometry.
Attached is the picture of the geometry.

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Nagi Elabbasi Facebook Reality Labs
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Posted: 1 decade ago Mar 21, 2014, 11:37 p.m. EDT
Hi Barrett,

One way to define constraints that prevent rigid body motions without causing localized stresses, and without preventing contraction/expansion, is to define displacement constraints on each end of the artery in a “distributed” sense. Conceptually you would fix the average X, Y and/or Z displacement of a boundary to be zero instead of fixing a specific point or the whole boundary.

You can do that by defining a Component Coupling operator, type Average then using it in a Global Constraint. For example if your operator is aveop1() you can set a global constraint to “aveop1(u)” to set the average displacement of the boundary in the X direction to zero.

Nagi Elabbasi
Veryst Engineering
Hi Barrett, One way to define constraints that prevent rigid body motions without causing localized stresses, and without preventing contraction/expansion, is to define displacement constraints on each end of the artery in a “distributed” sense. Conceptually you would fix the average X, Y and/or Z displacement of a boundary to be zero instead of fixing a specific point or the whole boundary. You can do that by defining a Component Coupling operator, type Average then using it in a Global Constraint. For example if your operator is aveop1() you can set a global constraint to “aveop1(u)” to set the average displacement of the boundary in the X direction to zero. Nagi Elabbasi Veryst Engineering

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