Iteratively updating stress/strain curve using experimental data

- January 13, 2020 at 11:37 am
  
  alexmarsh
  Subscriber
  
  Hi all,
  
  I'm attempting to use ANSYS to carry out a similar procedure to that carried out by Kamaya and Kawakubo (which they call "Iterative FEA prodcedure based on DIC measurement (IFD)") in the linked paper below:
  
  https://www.sciencedirect.com/science/article/pii/S0167663611000238/
  
  In brief, I would like to use an FEA model of a tensile test alongside experimental load/displacement results to create an accurate stress/strain curve for my sample material. I plan to go along approximately linear segments of the stress/strain curve used by ANSYS, iteratively updating each segment (i.e. changing the slope for that range of strain) until the load/displacement curve for that segment matches the experimental data. The model will use the load over time recorded by the loading device in the experiment. The linked paper makes the process clearer, and I have attached the flowchart used by the authors.
  
  However, I'm increasingly unsure that ANSYS has the capacity to do this - for example, it seems that ANSYS has no way of running a simulation until such-and-such a strain is reached. Am I just missing something, or is it impossible to do what I'm attempting with ANSYS?
  
  I would be grateful for any suggestions.
- January 13, 2020 at 5:24 pm
  
  DrDalyO
  Subscriber
  
  Hi Alex,
  
  Not sure I follow your question exactly. In Ansys, you have the ability to insert a custom stress-strain curve using either bilinear or multilinear isotropic hardening material properties in the Engineering Data tab. Should you require different stress strains in compression and tension you could follow one of my youtube videos on this (see below) for entering custom stress-strain data via a command file.
  
  You can run a simulation and then check the maximum strain results and then adjust the simulation forces to end at that exact strain value. You could also email me the paper to my email on my youtube channel info page.
  
  https://youtu.be/dLPa3TOW-20
  
  Regards,
  
  Drdalyo
- January 13, 2020 at 6:10 pm
  
  alexmarsh
  Subscriber
  
  Hi Drdalyo,
  
  Thank you for responding. I'm able to create a custom stress-strain curve in Engineering Data, my main concern was how to get ANSYS to end the simulation once a particular strain value is reached. As I understand it, I was right to think this can't be done directly, and your suggestion would be to run the simulation all the way each time, but to look only up to the strain value of interest. This seems like the best solution at the moment, so I'll probably run with it.
  
  Thanks again,
  
  Alex