void Ratio (e) in PDMY

[kamyarsa]

Hi, I want to use PDMY02 material. I have one problem regarding using it. I tried to follow the instruction to write the code for the material, I just wonder why changing the void ratio(e) does not change any results.
I even model a single 2d element and simulate a triaxial test with this material, still changing void ratio does not change anything!!!

Can someone explain why this happens? Am I doing something wrong?

# nDMaterial('PressureDependMultiYield02', matTag, nd, rho, refShearModul, refBulkModul, frictionAng, peakShearStra, refPress, pressDependCoe, PTAng, contrac[0], contrac[2], dilat[0], dilat[2], noYieldSurf=20.0, *yieldSurf=[], contrac[1]=5.0, dilat[1]=3.0, *liquefac=[1.0,0.0],e=0.6, *params=[0.9, 0.02, 0.7, 101.0], c=0.1)

ops.nDMaterial('PressureDependMultiYield02', matTag, 2 , rho, refShearModul, refBulkModul, frictionAng, peakShearStra, refPress, pressDependCoe, PTAng, 0.067 , 0.23 , 0.06 , 0.27, 20, 5.0, 3.0, *[1.0,0.0], 0.6, *[0.9, 0.02, 0.7, 101.0], 0.1 )

[mhscott]

OpenSeesPy does not use kwargs. Use 0.6 instead of e=0.6 in the argument list. Same with the other inputs.

[kamyarsa]

Yes, you're right. I did exactly as you said. You can see in my previous message that I do not use kwargs ( The first line is only a comment for reference). I do not have any problem in the running of analysis. The analysis starts and finishes properly but the results are the same while I change "e" from 0.6 to 0.9.
I would appreciate it if you could help me why this happens! How e is inputted in this constitutive model?

[najafi]

Hi, I want to use PDMY02 material. I have one problem regarding using it. I tried to follow the instruction to write the code for the material, I just wonder why changing the void ratio(e) does not change any results.
I even model a single 2d element and simulate a triaxial test with this material, still changing void ratio does not change anything!!!

Can someone explain why this happens? Am I doing something wrong?

# nDMaterial('PressureDependMultiYield02', matTag, nd, rho, refShearModul, refBulkModul, frictionAng, peakShearStra, refPress, pressDependCoe, PTAng, contrac[0], contrac[2], dilat[0], dilat[2], noYieldSurf=20.0, *yieldSurf=[], contrac[1]=5.0, dilat[1]=3.0, *liquefac=[1.0,0.0],e=0.6, *params=[0.9, 0.02, 0.7, 101.0], c=0.1)

ops.nDMaterial('PressureDependMultiYield02', matTag, 2 , rho, refShearModul, refBulkModul, frictionAng, peakShearStra, refPress, pressDependCoe, PTAng, 0.067 , 0.23 , 0.06 , 0.27, 20, 5.0, 3.0, *[1.0,0.0], 0.6, *[0.9, 0.02, 0.7, 101.0], 0.1 )

Hi,
did you use Standard Single Point (SSP) fully coupled (UP) elements? (for ex. SSPquadUP and SSPBrickUP)
As far as I know, these elements also have a void ratio. If you forget to update e for these elements, OpenSees probably overwrite the void ratio because elements are defined after materials.