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COU2DC/3DC
Description
Constitutive law for unilateral thermo-mechanical contact
The model
Thermo-mechanical analysis of problems involving unilateral contact between two bodies. Coulomb dry friction law is used. The contact condition is enforced via a penalty method or augmented Lagrangian method according to ISTRA(4). Heat transfer between the bodies depends upon the contact state.
- Contact occurs(pression non zero) heat transfer is computed according the contact thermal resistance
- Contact does not occur, heat transfer is computed by convection and radiation with constant coefficient.
In this case, the outside temperature is the following one :
- INDIC = 1 always the atmosphere temperature
- INDIC = 0 if the normal to the structure intersects one segment, this segment temperature is chosen; otherwise, the atmosphere temperature is used
- INDIC = 2 if the normal to the structure intersects one segment, this segment temperature is chosen; otherwise, no flux is computed (interest if 2 layers of contact element exist)
Files
Prepro: LCNTTH.F
Lagamine: COU2DC.F, COU3DC.F
Availability
| Plane stress state | YES |
| Plane strain state | YES |
| Axisymmetric state | YES |
| 3D state | YES |
| Generalized plane state | YES |
Input file
Parameters defining the type of constitutive law
| Line 1 (2I5, 60A1) | |
|---|---|
| IL | Law number |
| ITYPE | 280 |
| COMMENT | Any comment (up to 60 characters) that will be reproduced on the output listing. |
Integer parameters
| Line 1 (3I5) | |
|---|---|
| INDIC | 0, 1, 2 to define the outside temperature used in case of no contact (see Use paragraph) |
| NINTV | 1 (except in 3D dynamic where value $\neq$ 1 is possible) For the 3D state dynamic analysis: Number of sub-steps used to integrate numerically the constitutive equation in a time step |
| ISOL | 0, 1 or 4 |
| NTEMP | Number of temperatures at which THCON, CONVEC & RADIA parameters are given (see hereafter). Default value = 1 |
Real parameters
if NTEMP = 1
| Line 1 (7G10.0) | |
|---|---|
| AKP | penalty coefficient on the contact pressure $K_p$ |
| AKTAU | penalty coefficient on the shear frictional stress $K_{\tau}$ |
| PHI | COULOMB's friction coefficient $tg \phi $ |
| B | cohesion |
| TAUMAX | maximum contact friction (only for 2D state) (default value = $10^{20}$) |
| THCON | thermal resistance when contact occurs |
| CONVEC | convection coefficient h |
| Line 2 (4G10.0) | |
| RADIA | radiation coeficient $\sigma_0$ $\varepsilon$ where $\sigma_0$ is the Boltzman constant, and the $\varepsilon$ emissivity |
| CTQ | TAYLOR QUINNEY's coefficient to take into account the dissipation for heat computation a. CTQ = -1 $\Rightarrow$ flux = QB(3) b. CTQ $\in$ [0,1] $\Rightarrow$ QB(3) = $\Sigma (DISSIP/2*CTQ*\Delta t)$ c. CTQ $\geq$ 100 $\Rightarrow$ flux = DISSIP/2*(CTQ-100) Case a = semi-coupled analysis : thermal analysis Case b = semi-coupled analysis : mechanical analysis Case c = total coupled analysis |
| TAMB | atmosphere temperature |
| PRESID | residual pressure |
if NTEMP > 1
| Line 1 (5G10.0) | |
|---|---|
| AKP | penalty coefficient on the contact pressure $K_p$ |
| AKTAU | penalty coefficient on the shear frictional stress $K_{\tau}$ |
| PHI | COULOMB's friction coefficient $\phi$ |
| B | cohesion |
| TAUMAX | maximum contact friction (only for 2D state) (default value= $10^{20}$) |
| Line 2 (4G10.0) - Repeated NTEMP times | |
| TEMP | Temperature |
| THCON | Thermal resistance when contact occurs |
| CONVEC | convection coefficient h |
| RADIA | radiation coeficient $\sigma_0$ $\varepsilon$ where $\sigma_0$ is the Boltzman constant, and the $\varepsilon$ emissivity |
| Line NTEMP+2 (3G10.0) | |
| CTQ | TAYLOR QUINNEY's coefficient to take into account the dissipation for heat computation a. CTQ = -1 $\Rightarrow$ flux = QB(3) b. CTQ $\in$ [0,1] $\Rightarrow$ QB(3) = $\Sigma (DISSIP/2*CTQ*\Delta t)$ c. CTQ $\geq$ 100 $\Rightarrow$ flux = DISSIP/2*(CTQ-100) Case a = semi-coupled analysis : thermal analysis Case b = semi-coupled analysis : mechanical analysis Case c = total coupled analysis |
| TAMB | atmosphere temperature |
| PRESID | residual pressure |
Stresses
Number of stresses
4 for 3D state
3 for the other cases
Meaning
For the 3D state
| SIG(1) | normal contact pressure |
| SIG(2) | tangent contact stress in the $\xi$ direction |
| SIG(3) | tangent contact stress in the $\eta$ direction |
| SIG(4) | heat transfer |
The $\xi$ and $\eta$ correspond to the intrinsic co-ordinates of the contact element CFI3D
For the other cases
| SIG(1) | normal contact pressure |
| SIG(2) | tangent contact stress |
| SIG(3) | heat transfer |
State variables
Number of state variables
3
List of state variables
| Q(1) | 0 if the current state is elastic (no sliding) 1 if the current state is elastoplastic (sliding at contact) -1 no mechanical, nor thermical contact |
| Q(2) | amount of mechanical energy dissipated per unit area, due to friction |
| Q(3) | information concerning the mechanical dissipation into heat flow (for exact meaning see CTQ parameter above) |
laws/couc.1573733843.txt.gz · Last modified: 2020/08/25 15:34 (external edit)
