====== Contact elements ======
<note important>
Revision 2950 : Change of the default value for AREAINCONTACT property : new default = AIC_ONCE (AIC_NO before revision 2950)
</note>
===== Contact[2|3]DElement =====

For rigid-defo contact: ''Contact[2|3]DElement'' defines contact between a rigid entity under a given displacement (unmeshed geometric entity) and a meshed geometric entity which is part of the surface of the mesh. This element is therefore a one node element, called the slave, having 2/3 dofs in 2/3D.

For defo-defo contact: ''Contact[2|3]DElement'' defines contact between two meshed geometric entities, both part of the surface of the mesh. This element associates one node to a set of edges or faces.


=== Parameters ===
^   Name          ^     Metafor Code     ^  Dependency ^
| ''MATERIAL''    | Number of the [[doc:user:elements:contact:laws|contact material]] to consider |  -  |
| ''STIFFMETHOD'' | Method used to compute the stiffness matrix\\ = ''STIFF_ANALYTIC'' : analytic matrix (default)\\ = ''STIFF_NUMERIC''  : numerical matrix          |  -  |
| ''AREAINCONTACT''   | Parameter to taken into account the surface associated to a slave node to ponder contact forces : \\ Force = Penalty * gap * Area \\ = ''AIC_NO'' : not taking into account contact area (formally Area = 1.0) (:!: by default until Rev2950) \\ = ''AIC_USER'' : Area = value given in ''USERCONTACTAREA'' property \\ = ''AIC_ONCE'' : Area  = "Slave node surface computed based on initial configuration" (:!: default since Rev2950) \\ = ''AIC_ONCEPERSTEP''  :  Area = "Slave node surface recomputed at the beginning of each time step (take into account Slave node surface variations using an explicit scheme (to use if friction depends on the contact area, for example using Tresca's law) \\ = ''AIC'' : Area = "Node contact surface computed at each mechanical iteration". The contact stiffness matrix is adapted to Area modification (connectivity of contact elements also adapted)|  -  |
| ''USERCONTACTAREA'' | Contact Area Value for AIC_USER case  |  -  |
| ''AREAINCONTACTMETHOD''   | Method used to compute the slave node surface used to ponder contact forces\\ = ''AICM_GEOPHYS'', 0 : the calculation of the area is based on a geometrical approach in the physical space (by default).\\ = ''AICM_GEOREF'', 1 : the calculation of the area is based on a geometrical approach in the reference space.\\ = ''AICM_CONS'',  2  : the calculation of the area is based on an energy approach. |  -  |
| ''PRECONNORMALGAP'' | Accuracy set on the normal gap when using the [[doc:user:elements:contact:lag_aug|augmented Lagrangian]]. By default, no value since the method is deactivated. |  -  |
| ''PRECONTANGENTGAP'' | Accuracy set on the tangential gap when using the  [[doc:user:elements:contact:lag_aug|augmented Lagrangian]]. By default, no value since the method is deactivated.  |  -  |	
===== Tm[2]Contact[2|3]DElement =====

Thermomechanical contact element for rigid-defo or defo-defo, of the first or second order. Same as ''ContactElement'' but with a thermal field.

:!:Second order thermomechanical elements are not tested:!:

=== Parameters ===
^   Name          ^     Metafor Code     ^  Dependency ^
| ''MATERIAL''    |Number of the [[doc:user:elements:contact:laws|contact material]] to consider             |  -  |
| ''STIFFMETHOD'' | Method used to compute the stiffness matrix\\ = ''STIFF_ANALYTIC'' : analytic matrix (default)\\ = ''STIFF_NUMERIC''  : numerical matrix           |  -  |
| ''AREAINCONTACT''   | Parameter to taken into account the surface associated to a slave node to ponder contact forces : \\ Force = Penalty * gap * Area \\ = ''AIC_NO'' : not taking into account contact area (formally Area = 1.0) (:!: by default until Rev2950) \\ = ''AIC_USER'' : Area = value given in ''USERCONTACTAREA'' property \\ = ''AIC_ONCE'' : Area  = "Slave node surface computed based on initial configuration" (:!: default since Rev2950) \\ = ''AIC_ONCEPERSTEP''  :  Area = "Slave node surface recomputed at the beginning of each time step (take into account Slave node surface variations using an explicit scheme (to use if friction depends on the contact area, for example using Tresca's law) \\ = ''AIC'' : Area = "Node contact surface computed at each mechanical iteration". The contact stiffness matrix is adapted to Area modification (connectivity of contact elements also adapted) |  -  |
| ''USERCONTACTAREA''  | Contact Area Value for AIC_USER case |  -  |
| ''PRECONNORMALGAP'' | Accuracy set on the normal gap when using the [[doc:user:elements:contact:lag_aug|augmented Lagrangian]]. By default, no value since the method is deactivated. |  -  |
| ''PRECONTANGENTGAP'' | Accuracy set on the tangential gap when using the  [[doc:user:elements:contact:lag_aug|augmented Lagrangian]]. By default, no value since the method is deactivated.  |  -  |
| ''TOOLTEMP'' | Temperature of the tool in  a rigid-defo configuration ( By default, 293.0K )  |  time  |