Problem with Boundary constraint In FEM

[khalaq]

I am getting problem with applying boundary constraint. I am simulating a Stent geometry. It is totally support free. We need to extend along Z-axis. How can I apply boundary constraint. Please write here...

bye

Khalaq

 

[rb1957]

do you possibly mean "tent" ?

consider the real world ... if it is totally free, it'll fall down, or get blown away. it is secured somewhere.

if you constrain the structure at one point in the z-direction, then it'll be free to strain in z, and displace at the other end.

but then, maybe i don't understand your post ?

 

[prost]

We need more information!
Is the stent in force and moment equilibrium? If so, you can apply a RIGID BODY CONSTRAINT to the model to run the FEA simulation.

Is this 2D or 3D? How is it loaded, with an internal pressure? Or some other loading?

 

[40818]

Stent??

 

[tianle]

Your stent can never be "totally support free", Dude.
Did you mean it's suspended in vacuum far from the earth?
So you can either think of its loads or to simplify the boundary condition as a point constraint or sth.

Describing your model in more detail might draw more helps to you.

 

[corus]

A stent, I believe, is used in the arteries to open them up to allow blood to flow.
I would suspect that you can impose symmetry restraints to cater for any x and y translation. For the Z (axially) you'll have to restrain one end in order to pull it at the other end.

corus

 

[rb1957]

so it's something like an expanding collar that expands (driven by a spring i assume) untill it meets an external restraint (driven by the elasticity of the surrounding). so the edge on the "stent" should be attached to spring elements, which of course would be grounded. i guess you could model two springs (one for the stent, and one for surround) or you could combine the two mathematically.

 

[rb1957]

from wiki, for "stent" ...

In medicine, a stent is a tube that is inserted into a natural conduit of the body to prevent or counteract a disease-induced localized flow constriction.

you learn something new everyday ...
and sometimes it's usefull.