foot FEA question

[Liangliang Xiang]

Hi, I'm currently conducting foot FEA, but I don't know how to add foot plantar fascia, soft tissue, ligaments etc...
Could anyone give me some advices? Thanks so much!

 

[FEA way]

Check this thread, it contains the discussion about this topic:

https://www.eng-tips.com/viewthread.cfm?qid=456424

You will have to use multiple 1D elements such as springs, trusses and connectors to model ligaments/tendons and similar structures.

 

[Liangliang Xiang]

Thanks FEA way, I will check it and try to fix it.

 

[Liangliang Xiang]

Hi, FEA way,

How could I add Truss element to a assembly?

 

[FEA way]

Trusses are created in Part module, as wires. When you create a wire you can go to Property module and assign Truss section to it.

It might be easier to use axial connectors. These can be assigned to wires created in the Interaction module.

 

[Liangliang Xiang]

After I created a truss element.
Abaqus remind me that "Part dimensionality does not match the dimensionality of the existing instances" while I was trying to do the assembly in the 'Instance'. what's wrong in here?

 

[FEA way]

It seems that you created a 2D wire. If the remaining parts are 3D then the wire part needs to be in three dimensions as well.

 

[Liangliang Xiang]

Thank you very much for your patience and kind help!

Now it's in an assembly(Instance), but how could I combine them to one model?
And How to add cartilages between bones?

Thanks

 

[FEA way]

Truss elements can be connected to solids using kinematic coupling constraints.

You will most likely have to use solid elements to model cartillage. So you should create additional 3D solid parts for them. Or partition the bones.

 

[Liangliang Xiang]

Using Boolean operations to create cartilage? if is, how it can be done in Abaqus?

 

[FEA way]

Boolean operations in Abaqus can be performed on part instances. They are available in the Assembly module: Instance —> Merge/Cut. This way you can either merge two instances into one or cut instance using another instance as cutting tool. However, for cartillage you will rather need separate instances connected with bones (for example with tie constraint).

 

[IceBreakerSours]

Unsolicited advice:

Looking at this thread, I am afraid I must say these are the kinds of skills you need to learn in a class or under someone's supervision. You will encounter many (!) issues along the way once the model set-up is complete. If I were you, I would talk to my manager/supervisor. The sooner you have (ideally, local) help, the better off you will be.

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[Liangliang Xiang]

Thanks, You got me. I should learn more about FEA and Abaqus software.

 

[IceBreakerSours]

The intention was to offer advice (and not to get you in any way). You will be in much more control over the future of the project with a deeper skill-set, that is all. Relying on a free online forum for these sorts of questions seems like a precarious position to be in. But I have been wrong before.

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