Adding springs to an axisymmetric model

[dmackendh]

Im trying to create a porous viscoelastic model of cartilage..

I am modelling a small cylindrical plug so I am using an axisymmetric set-up. I drew my section and I needed to add springs between nodes to model cartilage fibres but when i tried to add the springs, the elements/nodes didnt show up, I only had the option to add a single spring across the section, connected to opposing vertices.

So after a lot of playing around, i created a 'mesh-part' which had an 'orphan mesh' and within this new part I was able to put the springs between individual nodes.

Is this the only way to add springs between mesh nodes?

It seems odd that I had to create a second part (the 'mesh-part') in order to do this.

What exactly is a 'mesh-part' and what is an 'orphan mesh' ??

 

[gurmeet2003]

Mesh part is same as an orphan mesh. In ABAQUS CAE one can work with the geometry. Usually when geometry for a part exists in CAE, the nodes and elements are directly not accessible. The advantage of working with the geometry is that it is easier to apply loads boundary conditions etc.
Also one can refine the mesh without losing the loads.

Before the model is solved all loads etc. are transferred to the finite element model (mesh). If one wants to use nodes and elements directly, one can create an orphan mesh part. The mesh in this part is not attached to any geometry.
The elements and nodes are directly accessible.

Gurmeet

 

[dmackendh]

Thank you. That was a very helpful explanation.

 

[brep]

This used to be a correct explanation, however, starting in V6.7EF (released at the end of last year) you can create surfaces and sets of individual (or groups of) nodes and elements even if they are on geometric parts. You can then put loads, bcs, constraints, history output requests, section assignments etc etc. Anything that you'd normally do with sets/surfaces. Note that if you remesh the geometry then the set/surface may become invalidated (and need reselection), but this is the only caveat.

 

[dmackendh]

Thanks again for the responses,

I thought I had figured it all out until I looked at my results and I realised that when I apply a displacement, it will only apply to one part or the other, but not both together.

Also I get a warning during sumission telling me that I have two unconnected regions in my model.

So.... is there a way to tie the two parts together? I need them to act as one part essentially. I thought the mesh-part would take on the properties of the original part and then I could just delete the original part? Maybe im wrong, would this totally void the mesh part if I deleted the original part?

Surely there must be a way to tie the two parts together?

 

[gurmeet2003]

It appears that you may be working with an assembly of two parts and not one part. In order to tie the two parts use tie constraints.

Gurmeet