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Question regarding 'update parameter' for hPerm/vPerm in pdmy02 with SSPquadUP elements

Posted: Tue May 26, 2026 2:57 pm
by javnetz2021
Hello everyone,

I am currently working on a numerical model to simulate soil liquefaction using the PressureDependMultiYield02 (pdmy02) material model alongside SSPquadUP elements.

I have a question regarding the update parameter command when changing permeability (hPerm and vPerm). I attempted to apply a permeability update to a specific region of my model. However, I am observing pore pressure (PP) accumulation across the entire domain, including areas where the permeability is supposedly set to a high value (k = 10).

This leads me to suspect that the parameter update is being applied globally to the entire material tag, rather than being restricted to the specific region I intended to target.

Could someone confirm if this is the standard behavior in OpenSees/STKO? If the command inherently updates the parameter for the entire material globally, I assume the correct workaround is to define two completely separate material tags for the different permeability zones.

Any insights or confirmation on this would be greatly appreciated. Thanks in advance!

Re: Question regarding 'update parameter' for hPerm/vPerm in pdmy02 with SSPquadUP elements

Posted: Mon Jun 08, 2026 7:43 am
by STKO Team
Unfortunately, the SSPBrickUP (as opposed to the others) only supports: xPerm, yPerm and zPerm parameters, as you can see from the source code:
PERM.png
PERM.png (66.31 KiB) Viewed 279 times