Shape memory alloy

- July 25, 2018 at 6:24 am
  
  Ankusham
  Subscriber
  
  I am trying to model shape memory effect with the geometry like horseshoe. i am doing it in 3 load step with initial body temperature 278.15 k
  
  1 Displacement loading of 5 mm on each end i;e to widen the opening
  
  2 Unloading i;e applying 0 displacement load at the two faces for elastic recovery
  
  3 Temperature loading 310.15 k to recover the plastic strain remains after unloading.
  
  To avoid nonlinear convergence problem, i used newton raphson method UNSYMMETRICAL, LARGE DEFLECTION ON, APPLY LOAD IN 300 SUB-STEP, ELEMENT SOLID 185(supportable for sma).
  
  Solution converges for 2 load step i;e loading and unloading, but at the start of very first sub-step of 3rd load step the solution i non convergent with error as some elements are HIGHLY DISTORTED.
- July 25, 2018 at 10:08 am
  
  Sandeep Medikonda
  Ansys Employee
  
  Hi Ankusham,
  
  Can you browse to the “Last Set” of results, select “Nonlinear Diagnostics” and highlight the item(s) that appear in the ‘Nonlinear Diagnostics – Postprocessing’ dialogue box?
  
  Also, are you performing a coupled thermal-structural analysis?
  
  Regards,
  
  Sandeep
- July 25, 2018 at 3:05 pm
  
  Sandeep Medikonda
  Ansys Employee
  
  Hi Ankusham,
  
  Can you share the material properties you are using in your model for the Shape Memory Alloy?
  
  As a first step, I would recommend you to take these properties and use them in one of the simple verification examples from the manual or even try your model with the properties listed in those examples, For Ex:
  
  Note that there are 3 verification examples available in the documentation:
  
  ANSYS Documentation > Verification Manuals > Mechanical APDL Verification Manual > I. Verification Test Case Descriptions > VM221
  
  ANSYS Documentation > Verification Manuals > Mechanical APDL Verification Manual > I. Verification Test Case Descriptions > VM251
  
  ANSYS Documentation > Verification Manuals > Mechanical APDL Verification Manual > I. Verification Test Case Descriptions > VM273
  
  Hope this helps.
  
  ~Sandeep
- July 25, 2018 at 5:15 pm
  
  Ankusham
  Subscriber
  
  Thank you sandeep,
  
  i am using static structural and VM221 is useful in my case. I modeled that correctly But in my case boundary condition, load, material properties are different.
  
  i look forward as per your suggestion.
  
  with regards
  
  Ankush