Learning Forum

[Haiquan]

Hello

I am performing hyperelastic material(EPDM) simulation using Yeoh 3rd Order. Both uniaxial test data and biaxial test data are used for curve fitting. The fitting result seems good as shown in Fig.1

My questions are:

1/Both my test data(uniaxial and biaxial) only contains tension(positive strain?) data, is it enough for a compressing load simulation as shown in Fig.2 ?

2/I launched a tensile case to validate the material model, but I found that there is gap between test and simulation as shown in Fig.3. What is the cause of this gap? Is it because I didn't introduce compressibility?

I attached Ansys file with version 2020 R1 if anyone is willing to check. Thank you in advance. Will you a happy new year!

Fig.1

[peteroznewman]

nTest data uses Engineering Stress and Strain.nSimulation results are True Stress and True Strain.nPut them on the same basis to see if curves give a closer match.n

[Haiquan]

Thank you very much for your quick answer! I convert engineering test data to true test data, it is now very close!nBy the way, any comment about my question 1?n

[peteroznewman]

nIf you want to simulation compression, it is better to have hyperelastic experimental data as well as tensile data, but you can get results with only tensile data. The circular section that is getting compressed in the Y direction is creating internal tensile stress in the X direction. I don't know the size of the error if you only have tensile data.n

[Haiquan]

Thank you very much for your comment!n