====== FAIL3 ======
3D fault interface
===== Description =====
Type: 213 \\
\\
{{ :elements:cfi3d.png?400|}}
The element consists of 4 or 8 nodes connected to the structure. The normal (red side in DESFIN) must go out of the structure. \\
\\
The foundation, defined by a series of triangular or quadrangular sides, by a cylinder or a truncated cone, 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. \\
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If the foundation is cylindrical, it is represented by 3 nodes. The first 2 nodes represent the limits of the cylinder axis. The last node has coordinates $(R, \phi, 0)$, where $\phi$ represents the rotation of the cylinder ($\phi=0$ initially). \\
If the foundation is a truncated condeit is also represented by 3 nodes. The first 2 nodes represent the limits of the truncated cone axis. The last has coordinates $(R_1, R_2, \phi)$ where $R_1$ and $R_2$ are the radius at node 1 and 2, and $\phi$ represents the rotation of the truncated cone ($\phi=0$ initially). \\
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The element can work in flow, mechanical, or coupled analysis. \\
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This element can use mechanical law [[laws:intme|INTME3]] or a classic law and flow law [[laws:intec3|INTEC3]].
\\ \\
Implemented by: J.P. Radu, 2000
==== Files ====
Prepro: FAIL3A.F \\
Lagamine: FAIL3B.F

===== Input file =====
^Title (A5)^^
|TITLE|"FAIL3" 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 ^^
|**If law = [[laws:intme|INTME2/INTME3]] (6G10.0/blank line)**||
|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)|
|**If law ≠ [[laws:intme|INTME3]] (6G10.0/3G10.0)**||
|All stresses vary as: $SIGnn=SI0nn+(Z*DSIG)$ \\ $SIGnl=SI0nl+(Z*DTAU)$||
|SI011|Stresses at the axis origin (y=0) \\ **expressed in local axes (z=0)**|
|SI022|:::|
|SI033|:::|
|SI012|:::|
|SI013|:::|
|SI023|:::|
|DSIG|Coefficient of normal stress variation along Z ( = 0 → constant SIGnn)|
|DTAU|Coefficient of tangent stress variation along Z ( = 0 → constant SIGnm)|
|RIGM|Penalty \\ = 1.0 by default \\ = 1/e inverse of the element thickness|
^Definition of the elements (5I5/8I5)^^
|NINTE|Number of integration points (1 to 10, 5 max can be drawn by DESFIN - recommanded value: 2)|
|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 [[lagamex:auto#4th_line_14i5|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 [[lagamex:auto#4th_line_14i5|ISTRA(4)]]). \\ Suitable for solids of different stiffnesses, both must be properly represented.|
|NODES(8)|List of nodes|
===== Results =====
**Stresses**: \\
__If law = [[laws:intme|INTME3]]__: \\
  * Pressure
  * Tangent stress
  * 0
  * 0
  * 0
  * Flow in the plane of the element $f_{x,loc}$, 
  * Flow in the plane of the element $f_{y,loc}$,
  * Stored flow, 
  * Transversal flow
__If the law is not [[laws:intme|INTME2/INTME3]]:__ \\
  * $\sigma_{11}$, $\sigma_{22}$, $\sigma_{33}$, $\sigma_{12}$,$\sigma_{13}$, $\sigma_{23}$ in local axes
  * Flow in the plane of the element $f_{x,loc}$, 
  * Flow in the plane of the element $f_{y,loc}$,
  * Stored flow, 
  * Transversal flow
**Internal variables**: \\ 
The first values are the ones relating to the mechanical law \\ 
For [[laws:intme|INTME3]], this will be: 
  * Plasticity indicator, 
  * Dissipation, 
  * Fault closing $V$, 
  * Fault opening $D$
\\ The 4 next values correspond to the contact geometry. They are: \\
  * The segment number of the foundation in contact
  * The interpenetration distance
  * The relative tangent rate 1
  * The relative tangent rate 2
The last values are those relating to the flow law; for [[laws:intec3|INTEC3]], they are:
  * 0
  * Intrinsic permeability in the plane of the element
  * The porosity
  * The specific mass of the fluid
  * Transversal transmissivity