The test data above is real test data for 316 Stainless steel (316SS) at 4 temperatures. I digitized this data from a web image. This will be useful test data for demonstrating material model calibration for temperature dependent metals (elasto-plasticity). There is an existing demonstration that used some realistic but synthetic data:
AL7075-T6 : Johnson-Cook Plasticity across temperatures
In the zip file at the bottom of this post, I have attached both the raw digitized test data and the data after clean-up in the material calibration app. With many curves in the original figure, it was hard to digitize near the stress-strain origin. I corrected for this by using the clean-up tools using the regularization feature.
The images and video below use the current public cloud, 2024x FD01, HotFix 1.22 to calibrate a temperature dependent material model : the Elastic modulus is a tabular function of temperature and the Johnson-Cook hardening law has its own parameters for temperature dependence. For the current public release, temperature dependence is not available in every elastic-plastic material model.
As we start to calibrate the JC hardening law, it is worth recalling the equation below. The equation tells us a few procedural details. Using this procedure greatly enhances the calibration success.
- First calibrate just the A, B and n parameters to the lowest temperature dataset. (with "m" set to zero)
- Set "m" to 1
- Set The Melting_Temperature parameter to a value higher than the highest temperature of the data.
- Set the Transition_Temperature parameter to the lowest temperature of the data.
If this Johnson-Cook plasticity model is run for FE temperatures equal to, or greater than the Melt_Temperature, the yield stress becomes zero and the FE run will most likely fail.
This is an image at the end of the calibration:
The zip file below contains the following:
- The raw and cleaned test data (2 separate Excel files)
- The file 316SS_temperatures_start.3dxml (created with version 2024x HotFix 1.22)
Back to: Sharing Material Test Data
Back to: Calibration examples, including narrated videos
Back to: Material Modeling and Calibration - An Overview and Curriculum
