Calculation of Thermo-poroelastic deformation using PDE
Posted 12 févr. 2019 02:05 UTC−05:00 Mechanical, Equation-Based Modeling Version 5.4 0 Replies
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Hi. I'm very new to COMSOL. I want to calculate thermo-poroelastic deformation in 2-D axissymmetric cylinder.
I have three questions. (1) How can I import values in a text file as format of [ x, z, value ] (value is change in pore pressure or change in temperature at each grid). Change in pore pressure and temperature were calculated beforehand by TOUGH2, which is a famous fluid flow simulator.
(2) How can I assign imported values into each mesh element.
(3) How can I implement stress tensor, including terms of thermomal expansion and pore-pressure-induced expansion (below formulation), at each mesh element.
stress(i j) = λ* (volumetric strain)δ(ij) + μstrain(i j) + βΔPδ(ij) + αKΔT*δ(ij)
i, j : component index
δ(ij) : Kronecker delta β : Biot-Willis coefficient α : thermal expansion coefficient K : bulk modulus
ΔP : pore pressure change (input from text file whose format is [x, z, ΔP] ) ΔT : change in temperature (input from text file whose format is [x, z, ΔT] )
I tried using diagonal "External stress" in "Structure Mechanics" module, but I couldn't find how to assign different ΔP & ΔT value at different element.
Next, I tried implenting thermo-poroelasicity using general form PDE module. However, coservative flux term (Γ), which corresponds to stress, cannot be defined detailed anymore (I want to make the constitutive ralation of thermo-poroelasticity described in above equation).
Thank you in advance.