ANSYS vs. MCalibration Mooney Rivlin Constant Mismatch
Im currently working on modelling hyperelasticity. As such, I have some uniaxial tension test data that I use to obtain Mooney Rivlin constants (9 paramter). For this I used ANSYS and MCalibration. However, these two softwares give me very very different values for the same dataset. ANSYS gives very high values (both negative and positive). However it is an exact match unlike MCalibration which doesnt exactly match the data at low strains as shown.
I made a UMAT for LS DYNA based on 9 parameter Mooney Rivlin model. The values given from Mcalibration work but ANSYS coefficients lead to instability. Any idea how or why this happens?