The Nitinol test data above was digitized from Figure 2 of the 2017 paper by Duerig, The Measurement and Interpretation of Transformation Temperatures in Nitinol.  We will use it in this post to talk about the calibration of a material model that contains these material attributes:

*Elastic

*Superelastic

*Superelastic Hardening

*Superelastic Hardening Modifications. 

Note: There is an existing post that discussed calibration of just the *Superelastic part:   Nitinol, superelastic material

In the figure above, there are several "transition plateaus".  During the transition to/from austenite / martensite, the stress strain segment is nearly horizontal.  The figure above shows that during loading the "loading transition plateaus" for the three stress-strain curves are virtually on top of each other. It also shows that during the unloading, the "unloading transition plateaus" are distinct from one another.  The unloading transition plateau is lowered by the accumulated plastic strain.  The Abaqus keyword *Superelastic Hardening Modifications is used to capture this effect. 

The videos below were created using R2026x HotFix 4.26 of the Material Calibration App.  This first video focuses on the use of *Superelastic

The 2nd video adds the *Superelastic Hardening to capture plasticity.

The 3rd video adds the *Superelastic Hardening Modifications.

Here is an image of the final material model. 

The zip file below contains an Excel file of the digitized data and several 3dxml files from the Material Calibration App.  The 3dxml files would require R2026x HotFix 4.26 or later. 

Back to:  Sharing Material Test Data

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