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FAIF3
3D fault interface
Description
Type: 227
The element consists of 4 or 8 nodes (DoF 1, 2, 3, 4, 5, and 6) relating to one side of the fault (= the structure), and 4 or 8 additional nodes to discretize the flow of water, gas, or temperature inside the fault (DoF 4, 5, and 6). It also relates to a predefined foundation.
The normal (red side in DESFIN) must go out of the structure.
The foundation, defined by a series of triangular or quadrangular sides, is defined in the “FOUND” section of the *.lag file. If the foundation is defined by a series of sides, the normal is given by the product of vectors $\vec{12}$ and $\vec{13}$ built on the nodes of the foundation $\vec{n}=\vec{12} \wedge\vec{13}$ of each side. This normal must be directed inwards the foundation.
This element is dedicated to soil mechanics and in particular to structure-structure contact (fault). It includes pressure, friction, flows axial to the fault (water, gas, thermal), and two (x3) flows (water, gas, thermal) transversal to the fault (along the thickness).
The element can work in coupled mechanical-water-air-temperature analysis, with 6 DoF.
This element can use mechanical law INTME3 or a classic law and flow law INTFL3.
Warning: When using renumbering of the DoFs, only directional renumbering works.
Implemented by: J.P. Radu, 2007
Files
Prepro: FAIF3A.F
Lagamine: FAIF3B.F
Input file
| Title (A5) | |
|---|---|
| TITLE | “FAIF3” in the first 5 columns |
| Control data (3I5) | |
| NELEM | Number of elements |
| INSIG | = 0 no initial stresses |
| = 1 → initial stresses | |
| Initial stresses - only if INSIG = 1 (6G10.0) | |
| The pressure varies as: $PRESS = PRES0 + (Z*DPRES)$ Tau varies as: $TAUn = TAUn0+(Z*DTAUn)$ |
|
| PRES0 | Pressure of the contact at the axis origin |
| DPRES | Coefficient of variation of the pressure along Y (= 0 → constant pressure) |
| TAU10 | TAU along direction 1 at the axis origin |
| DTAU1 | Coefficient of variation of TAU1 along Z (= 0 → constant TAU1) |
| TAU20 | TAU along direction 2 at the axis origin |
| DTAU2 | Coefficient of variation of TAU2 along Z (= 0 → constant TAU2) |
| Definition of the elements (5I5/8I5/8I5) | |
| NINTE | Number of integration points (1, 4, or 9) |
| LMATM | Mechanical law number |
| LMATF | Flow law |
| IFOND | Number of the foundation or tool If the foundation number is equal to 0, the boundary thermal flow is calculated with the ambient, without mechanical contact with any foundation. |
| IRIGF | Type of contact |
| 0 → rigid foundation or tool | |
| 1 → uncoupled solid/solid contact One contact element on each structure, the interpenetration distance is divided by 2. Suitable for solids with similar stiffnesses. |
|
| 2 → coupled solid/solid contact Only one contact element must be defined on a solid, the other being its foundation. The computation of MBAND and NHICO must be actualized (see ISTRA(4)). Suitable for solids of different stiffnesses, with one (the foundation) can be more roughly approximated. |
|
| 3 → coupled solid/solid contact One contact element on each structure, the force is divided by 2. None of the structure is privileged. The computation of MBAND and NHICO must be actualized (see ISTRA(4)). Suitable for solids of different stiffnesses, both must be properly represented. |
|
| NODES(1 to 8) | List of nodes on the structure side. Nodes 5 to 8 can be 0; in that case the element is of linear degree |
| NODES(9 to 16) | List of nodes inside the fault. Nodes 5' to 8' can be 0; in that case the element is of linear degree |
Results
Stresses (24):
- Pressure
- Tangent stress in direction 1
- Tangent stress in direction 2
- 0
- Longitudinal water flow $f_{w,x,loc}$ in the plane of the element,
- Longitudinal water flow $f_{w,y,loc}$ in the plane of the element,
- Stored water flow,
- “FI” (between Foundation and Inside) transversal water flow
- “IS” (between Inside and Structure) transversal water flow
- Longitudinal gas flow $f_{g,x,loc}$ in the plane of the element,
- Longitudinal gas flow $f_{g,y,loc}$ in the plane of the element,
- Stored gas flow,
- “FI” (between Foundation and Inside) transversal gas flow
- “IS” (between Inside and Structure) transversal gas flow
- Longitudinal thermal flow $f_{t,x,loc}$ in the plane of the element,
- Longitudinal thermal flow $f_{t,y,loc}$ in the plane of the element,
- Stored thermal flow,
- “FI” (between Foundation and Inside) transversal thermal flow
- “IS” (between Inside and Structure) transversal thermal flow
- Longitudinal vapor flow $f_{v,x,loc}$ in the plane of the element,
- Longitudinal vapor flow $f_{v,y,loc}$ in the plane of the element,
- Stored vapor flow,
- “FI” (between Foundation and Inside) transversal vapor flow
- “IS” (between Inside and Structure) transversal vapor flow
Internal variables (4+2+25 = 31):
The first values are the ones relating to the law
For INTME2/INTME3, this will be:
- plasticity indicator,
- dissipation,
- fault closing $V$,
- fault opening $D$
The 2 next values correspond to the contact geometry. They are:
- The segment number of the foundation in contact
- The interpenetration distance
The last values are those relating to the flow law; for INTFL3, they are:
- The relative permeability to water
- The relative permeability to gas
- The porosity
- The saturation to water
- The suction
- The specific mass of water
- The specific mass of gas
- Peclet number
- The water content
- The specific mass of vapor
- The vapor pressure
- The relative humidity
- The mass of liquid water per unit volume
- The mass of dry air per unit volume of soil
- The mass of vapor per unit volume of soil
- The intrinsic longitudinal permeability
- The gas saturation
- The partial pressure of hydrogen (not used)
- The water pressure inside the fault
- The gas pressure inside the fault
- The temperature inside the fault
- The transversal transmissivity of water
- The transversal transmissivity of gas
- The thermal transversal transmissivity
- The thermal conductivity
