====== CTMLC ======
2D interface-joint \\
:!: Still under development (?) - Last update: september 2003 (S. Castagne) 
===== Description =====
{{  :elements:cntcp.png?400|}}
The element has 2 or 3 nodes (linear or parabolic) and is related to a foundation or a tool. \\ \\
This element is designed for the study of polycristalline material and mainly to the representation of interfaces such as grain boundaries. It includes pressure, friction, and can also include the axial and transverse thermal flows at the boundary. \\ \\
Convention: when the element is considered in increasing order of nodes (1 → 2 → 3), the first body is to the left, and the foundation to the right. \\ \\
This element can be used with: 
  * Law [[laws:couc|COU2DC]] (transverse flow computed in the law);
  * Law [[laws:thsol2|THSOL2]] specific to the damage of grain boundaries (no thermal flow);
  * Mechanical law [[laws:intme|INTME]] + flow law INTTH1 (this law can only be called by CTMLC)
  * A classic mechanical law + flow law INTTH1 (this law can only be called by CTMLC)

\\
It can be used in plane strain/stress state, generalized plane state, or axisymmetric state. It can be used for mechanical, thermal, or thermo-mechanical analysis. \\ \\
Please, take care to give a value to the parameter DMAX (Lagamine execution data) that imposes the maximum distance between the element and the associated foundation. For example DMAX=0.01. \\ \\
Type: 216 \\

==== Files ====
Prepro: CTMLCA.F \\
Lagamine: CTMLCB.F

===== Input file =====
^Title (A5)^^
|TITLE|"CTMLC" in the first 5 columns|
^Control data (3I5)^^
|NELEM|Number of elements|
|INSIG|= 0  no initial stresses|
|:::  |= 1 initial stresses (see below) |
|IDOMA|Number of the ES group to which the elements are connected (necessary in case of remeshing)|
^Initial stresses - only if INSIG = 1 ^^
|**If law = [[laws:couc|COU2DC]] or [[laws:intme|INTME]] (4G10.0)**||
|The pressure varies as: $PRESS = PRESS0 + (Y*DPRES) \text{ for } P\geq 0$ \\ Tau varies as: $TAU = TAU0+(Y*DTAU)$||
|PRES0|Pressure of the contact at the axis origin|
|DPRES|Coefficient of variation of the pressure along Y (= 0 → constant pressure)|
|TAU0|TAU at the axis origin|
|DTAU|Coefficient of variation of TAU along Y (= 0 → constant TAU)|
|**If law ≠ [[laws:couc|COU2DC]] or [[laws:intme|INTME]] (7G10.0)**||
|All stresses vary as: $SIGnn=SI0nn+(Y*DSIG)$||
|SI011|Stresses at the axis origin (y=0) \\ expressed in local axes|
|SI022|:::|
|SI012|:::|
|SI033|:::|
|DSIG|Coefficient of stress variation along Y ( = 0 → constant stress)|
|DTAU|:::|
|RIGM|Penalty \\ = 1 by default \\ = 1/e inverse of the element thickness|
^Definition of the elements (6I5/3I5)^^
|NINTE|Number of integration points (1 to 10, 5 max can be drawn by DESFIN - recommanded value: 2)|
|LMATM|Mechanical law|
|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.|
|INTYP|Type of numerical integration (recommanded value: 0) \\ 0 → Gauss \\ 1 → Lobatto \\ 2 → Newton-Cote|
|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|List of nodes (2 or 3)|
===== Results =====
__Stresses:__ \\
If the law is [[laws:couc|COU2DC]] or [[laws:thsol2|THSOL2]] or [[laws:intme|INTME]]: \\
Pressure, tangent stress, 0, 0, longitudinal flow, stored flow, transverse flow \\
For other laws: \\
$\sigma_{11}$, $\sigma_{22}$, $\sigma_{12}$, $\sigma_{33}$ in local axes, longitudinal flow, stored flow, transverse flow
\\ \\
__Internal variables:__ \\
The first values are the ones relating to the law. \\ The last values correspond to the contact geometry. They are: \\
  * The segment number of the foundation in contact
  * The interpenetration distance
  * The jacobian
  * NOCO the contact indicator given by CALFON
  * The relative tangent rate
  * The cumulated relative tangent rate
  * The thickness of the element in the case of generalized plane state
  * The last values are that of the flow law if there is one.