Hello,
I am currently simulating a triaxial compression test on a rock specimen under different confinement pressures (uniaxial, 10 MPa, 20 MPa, and higher). The stress–strain curves and the associated FISH functions work as expected for the 10 MPa case. However, when I use the same parameters at higher confinement (e.g., 20 MPa), the stress–strain response does not produce the expected results.
To speed up the simulations, I adjusted the strain rate from 0.05 to 2. This modification worked well for the 10 MPa confinement, but for the 20 MPa case, the results still fail to converge to a reasonable curve, even with different strain-rate values.
I am using the Material Modeling Support Package and have attached the parameters I used as well as a figure showing the result of the 20 MPa test.
Here are the key parameter settings I applied:
fish define ctSetParams
; Set Compression-Test Parameters
ct_testType = 0 ; test-type code (0: confined, 1: unconfined, 2: uniaxial strain)
ct_Pc = 10.0e6
ct_Pc = 20.0e6
ct_eRate = 0.05
ct_eRate = 2
ct_loadCode = 0
ct_loadFac = 0.8
end
I would greatly appreciate any guidance on why the 20 MPa confinement test is not behaving as expected and whether additional adjustments are needed to the parameters for higher confinement levels.
Thank you for your support.
Best regards,
Alaa
