Table of Contents
EHMIC
Plane or axisymmetric state
Description
2D Multi-scale Coupled Analysis in large deformations: Mechanical-Water-Air.
Type: 283
The element is defined by 8 nodes indicated in NODES according to the order presented in the figure. 4 integration points are used for the interpolation.
The mechanical constitutive laws that can be used with this element are, for instance:
- ELA: Elastic constitutive law
- EP-PLASOL: Elasto-plastic constitutive law with linear elasticity
- ORTHOPLA: Elasto‑plastic constitutive law with linear anisotropic elasticity
The flow constitutive laws that can be used with this element are, for now:
- HMIC: Hydraulic micro law with WA coupling and implicit mechanics
Implemented by: F. Bertrand & G. Corman (2019)
The framework definition of this element can be found in Corman (2024)1).
Files
Prepro: EHMICA.F
Lagamine: EHMICB.F
Input file
| Title (A5) | |
|---|---|
| TITLE | “EHMIC” in the first 5 columns |
| Control data (4I5) | |
| NELEM | Number of elements |
| INSIG | = 0 → No initial stress = 1 or 2 → Initial stresses |
| Initial stresses - Only if INSIG > 0 (4G10.0) | |
| If INSIG=1: $\sigma_y=\sigma_{y0}+yd\sigma_{y}$ If INSIG=2: $\sigma_y=min(\sigma_{y0}+yd\sigma_y,0)$ |
|
| SIGY0 | $\sigma_{y0}$ effective stress $\sigma_y$ at the axes origin |
| DSIGY | Effective stress gradient along Y axis |
| AK0X | $k_0$ ratio $\sigma_x/\sigma_y$ |
| AK0Z | $k_0$ ratio $\sigma_z/\sigma_y$ (if AK0Z=0, AK0Z=AK0X) |
| The computation of SIGY0 and DSIGY must take into account the apparent specific mass, defined as \[\rho_a'=[(1-n)\rho_s+nS_w\rho_w]-\rho_w\] where: $\rho_s$ is the solid specific mass - this represents the specific mass of a fictive sample where ther is no porosity, i.e. where the grains occupy the whole volume of the sample $\rho_w$ is the fluid specific mass $n$ is the porosity defined in the flow law related to the element $S_w$ fluid saturation, ∈ [0,1] |
|
| Definition of the elements (6I5/16I5(/9I5)) | |
| NNODM | Number of nodes for the mechancial description: 8 |
| NINTM | Number of integration point for the mechanical description: 4 |
| LMATM | Mechanical law |
| NNODP | Number of nodes for the flow description: 8 |
| NINTP | Number of integration points for the flow description: 4 Must be equal to NINTM |
| LMATF | Flow law |
| NODES(NNODEM) | List of nodes |
| Definition of the hydraulic micro-elements in the microstructure (1I5/4I5) | |
| NUMEL2 | Number of hydraulic micro-elements |
| IELEM2 | No. of the hydraulic micro-element |
| ILAW | Type of element: 1=bedding plane, 2=bundle of tubes, 3=bridging plane |
| NDUN | No. of the micro-node at one side of the micro-element |
| NDDEUX | No. of the micro-node at the other side of the micro-element |
| Definition of the hydraulic micro-nodes in the microstructure (1I5/10I5) | |
| NUMNDH | Number of hydraulic micro-nodes |
| INOD2 | No. of the hydraulic micro-node |
| IEDGE | No. of the microstructure boundary to which belong the micro-node: 0=none, 1=left or bottom, 2=right or top |
| IELUN | No. of the 1st micro-element connected to the micro-node |
| IELDEUX | No. of the 2nd micro-element connected to the micro-node |
| IELTROIS | No. of the 3rd micro-element connected to the micro-node |
| IELQUTR | No. of the 4th micro-element connected to the micro-node |
| IELCINQ | No. of the 5th micro-element connected to the micro-node |
| IELSIX | No. of the 6th micro-element connected to the micro-node |
| IELSEPT | No. of the 7th micro-element connected to the micro-node |
| IELHUIT | No. of the 8th micro-element connected to the micro-node |
Results
- Stresses (in global axes)
- Mechanical stresses $\sigma_x$, $\sigma_y$, $\sigma_{xy}$, $\sigma_z$
- Flow in water $f_{wx}$, $f_{wy}$, $f_{w,stored}$
- Flow in air $f_{ax}$, $f_{ay}$, $f_{a,stored}$
- Advection dissolved gas flux $f_{adx}$, $f_{ady}$
- Diffusion dissolved gas flux $f_{addx}$, $f_{addy}$
- Advection gaseous gas flux $f_{agx}$, $f_{agy}$
- Internal variables:
- Internal variables of the mechanical law
- Internal variables of the flow law
1)
Corman, G. (2024). Hydro-mechanical modelling of gas transport processes in clay host rocks in the context of a nuclear waste repository. PhD thesis, University of Liège. https://hdl.handle.net/2268/307996