Stent crimping
Stent crimping
(OP)
Hello,
I am trying to crimp a stent with magnesium material.
I am getting error messages of missing element property definitions even after many attempts.
Could anyone please look at the file and provide some guidance.
And also I am not sure of the boundary conditions while running it says too many increments or too little increments.
Could you please suggest what's wrong with the model in order to complete the exact simulation process?
I am trying to crimp a stent with magnesium material.
I am getting error messages of missing element property definitions even after many attempts.
Could anyone please look at the file and provide some guidance.
And also I am not sure of the boundary conditions while running it says too many increments or too little increments.
Could you please suggest what's wrong with the model in order to complete the exact simulation process?





RE: Stent crimping
In general:
There is special functionality in Abaqus to model stent crimping. If you are commercial customer, then you can access the Support system and check the Answer QA00000018351.
https://www.3ds.com/support/knowledge-base/
RE: Stent crimping
I am student working on research with school provided software.
RE: Stent crimping
1. Missing property definitions
2. Independent variables must be arranged in ascending order.
Could anyone please suggest the corrections to be done for this model?
RE: Stent crimping
You should mesh the crimp surface with reduced-integration surface elements (SFM3D4R) and assign a surface section. That's what's causing your first error. Also the slope of the plastic stress strain curve is negative between the last two points - you might want to check that. Also you've meshed your stent with linear tets (C3D4). I would avoid using these elements for modelling a stent.
Check the literature, there is a ton of published work on FEA of stents.
RE: Stent crimping
RE: Stent crimping
And element type-family in mesh do not provide 3D stress option. Why does this happen when a stent model is changed? How could this be fixed?
RE: Stent crimping
RE: Stent crimping
Yes, I am trying to assign solid to surface.
The stent that is attached in above posts could be assigned 3d stress.
But when the stent design is changed then this option is not available in Abaqus.
Thickness of stent is changed from 0.08mm to 0.14 mm, even then this option is not working.
The design itself is considered as shell part.
RE: Stent crimping
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RE: Stent crimping
Since last few weeks trying to understand the concepts and following the tips provided in other posts in this forum.
And checked this site for element types.
http://imechanica.org/files/l2-elements.pdf
The cad model is designed in Solidworks. Changed the file from IGES (imports-shell faces) to SAT (imports-solid faces). SAT file provides 3D stress option in element type but HEX-C3D8R is not allowed to choose for the mesh. Only tets are allowed.
I don't understand why solid feature is differing from one stent design to other although have same thickness of 0.08mm.
RE: Stent crimping
This is basic stuff and shouldn't take weeks to work through. These steps (geometry,partition,mesh,section) are explained well in the documentation - CAE Users guide, Analysis Users guide and Example Problems guide. Sounds like a chore but you would save yourself a lot of time and trouble by working through them.
RE: Stent crimping
Thank you for the information and explaining the element that could be used in the simulation process. As I was going through other posts C3D8 was recommended. So, I thought that was the only option to be used for stent analysis. That's the reason I was looking for solid faces. I was trying other methods for crimping from past few weeks like designing plates etc. I am following your suggestions provided in the previous post - http://www.eng-tips.com/viewthread.cfm?qid=356649
Thank you for all your suggestions.