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Stent Modelling

  • Thread starter Thread starter graeham
  • Start date Start date
G

graeham

Guest
Hi All,

I am new to Creo, but have done a bit of design (including stents) on Unigraphics/NX and Solidworks.

I am trying to model a stent (such as seen below) for export to Abaqus for FE and CFD.

View attachment 6055

I've tried a few different approaches, all that have ended up with me bashing my head on my desk from not understanding Creo's features.

My main strategy has been to start with a unit cell (or part of one), and tessellate it through the pattern function.

I start with a sketch of half a unit cell:
View attachment 6056

Then I sweep a rectangular cross section along the initial sketch. I then mirror the resulting solid twice to get the other half of the unit cell.
View attachment 6057

Then I make the unit into a pattern of 5x20 unit cells.


This is where things get messy (although this could be a symptom of doing something wrong earlier?). The cells don't quite align nicely - there is either overlap or underlap. I think the answer would be some kind of "unite" function, where the exterior surface would be saved from overlapping. There is a small 'lip' from where the unit cells don't quite align. I think I could fix this by either being more careful with the first sketch that the sweep was made with, or by adding rounds at this stage to "wipe" over them. When I try to add rounds at this point, the tool takes the edge as being for two separate solids.
View attachment 6059

I think the last step would be to use a Toroidal Bend to wrap the plane into a cylinder. This always fails when I try, and also fails with just the one unit cell. I am able to get it to roll with just a rectangular sheet, so I think I do know the tool well enough - I'm thinking its a problem with the solid I'm using?

Thanks for any help or advice!!

EDIT:
File is at http://www.filehosting.org/file/details/426385/stentpiecemeal.prt.9

Sorry I was having trouble uploading it here, I think it was unhappy with the .prt.9 extension
 

Attachments

  • Covidien-EverFlex-straight.jpg
    Covidien-EverFlex-straight.jpg
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  • StentSketch.jpg
    StentSketch.jpg
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  • StentSweep.jpg
    StentSweep.jpg
    81.7 KB · Views: 17
  • StentPlane.jpg
    StentPlane.jpg
    91.4 KB · Views: 20
  • StentOverlaps.jpg
    StentOverlaps.jpg
    78.4 KB · Views: 14
Last edited:
I may be able to help, at least try to help, but without the part file, i cant try. :)
 
I was halfway through modeling this when you uploaded the part, so i worked from scratch and quickly modeled this.so its dirty modeling. see if it helps. :)unsuppress all features to see the model. (because its curved in 1 direction only, you should use spinal bend.)https://docs.google.com/file/d/0BzwwE53MwdQ4d20wVWQ0OUVmUU0/edit?usp=sharing
%25255BUNSET%25255D.png
 
Last edited:
If its what you want, please make a reference to my contribution in your paper as well :)
 
Thanks - that is a HUGE help to me. Also thanks to Jonathan for your emailed advice and help.
 

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