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Recent content by ryankb

  1. ryankb

    *SUPERELASTIC nitinol built-in definitions

    Dave- I've completed those steps, and it all works just fine. The problem arrises, however, when doing the following: tension to 6%, unload, reapply tension to 12%, unload, reapply tension to 16%, unload, reapply tension to 20% When tensioning to the 16% and 20% loops, the upper plateau...
  2. ryankb

    *SUPERELASTIC nitinol built-in definitions

    I am working on transitioning over to the built-in *Superelastic definitions of nitinol in Abaqus, and at the same time working to include plasticity (new model requires very high strains). I'm having a rough time including the Material Hardening and Material Hardening Modifications. I built a...
  3. ryankb

    Dual varying linear pattern help!!

    I'm stuck. What I'm trying to do doesn't seem that difficult logically, but I simply cannot get the software to make it happen - and I really don't want to have to manually edit a TON of dimensions. It's a plate with holes. The holes are actually small round-ended slots. I want to do three...
  4. ryankb

    Import analysis issues - stresses dropping rapidly

    Hello all, I'm hoping someone can shed some light into an issue I've been having this week. I'm running Abaqus explicit, a nitinol product is hitting a wall. Nitinol is modeled as beam elements, wall is solid elements. I think something with the restart isn't quite working properly, because in...
  5. ryankb

    Contact interaction not working for restart/import file

    I am coming back to this thread after trying a lot of things, and I'm still stumped. I do get a CPRESS value, but it's e-5, and hardly where I'd expect there to be any values. Any other thoughts of things to look at? I've tried defining contact pairs instead of relying on general contact, and...
  6. ryankb

    Contact interaction not working for restart/import file

    In the previous analyses I had not requested COPEN or CSTATUS. However, I was able to plot CPRESS on my rubber material, and it has non-zero values.
  7. ryankb

    Contact interaction not working for restart/import file

    I'm working on an explicit model, nitinol mesh inside a tube. I've completed the loading process in a previous analysis, and now I'm using it for the base of an import model to continue the analysis and release it against a piece of rubber. So, I've successfully brought everything in, ran it...
  8. ryankb

    Explicit Displacement B.C. after anneal step

    The amplitude definition is correct - that was one of the first things I checked. I do have a displacement jump warning - but I have multiple steps with displacements and I assumed this was what it was from. I'll look more at that warning and what it's about.
  9. ryankb

    Explicit Displacement B.C. after anneal step

    I'm running a nitinol explicit simulation using displacement B.C.'s to do the heat setting procedure. I'm doing a multi-step process, so I have an anneal step in the middle. This is causing me difficulties with my B.C.'s however. Say I want to displace by 2mm. In the B.C. definition, for Step1...
  10. ryankb

    stent wire / expansion surface contact problems

    Yes, you are correct on shell and beam. You also assumed the correct interaction (blue interact with imaginary outer surface). Is it just not possible with standard? I have an explicit example which I followed (but changed to standard), which when solved in explicit does have the offset. I do...
  11. ryankb

    stent wire / expansion surface contact problems

    I'm having some difficulty defining contact/interaction between my stent and expansion cylinder (wire stent). I'm not getting what I'm expecting from my results. It is running to completion without errors, but when viewing the results, it looks like my surface is interacting with the actual...
  12. ryankb

    Using Plasticity definitions in Nitinol UMAT - finding some interesting problems

    I too was pulled away from this simulation early this week, so don't worry. Yes, the material is calibrated. The test data and single-element data are completely on top of each other. I'm assuming you meant the elastic section is quite flat? That is quite typical of the nitinol and processing...
  13. ryankb

    Using Plasticity definitions in Nitinol UMAT - finding some interesting problems

    That is actually what is plotted above. The pinkish color is the single element test. It overlaps the graph above so it's difficult to see the underlying tensile data
  14. ryankb

    Using Plasticity definitions in Nitinol UMAT - finding some interesting problems

    The single element model shows good agreement with the data:
  15. ryankb

    Using Plasticity definitions in Nitinol UMAT - finding some interesting problems

    Here's a quick excel graph of the material definitions and how they work/don't work.... Focus on what's to the right of the flag... Green: actual data. When I put the datapoints in, it fails most of the way through the crimp step, but typically somewhere around the 11-ish% strain mark. Red...
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