Constitutive law for unilateral mechanical contact with creep damage
Creep damage analysis for polycrystalline materials. The contact and damage evolution conditions at the grain boundary are enforced via a penalty method. A threshold value is defined for crack propagation. When this value is reached, the interface and its foundation are no longer in contact
Prepro: LCRDAM.F
Lagamine: CREDAM.F
| Plane stress state | YES |
| Plane strain state | YES |
| Axisymmetric state | YES |
| 3D state | NO |
| Generalized plane state | YES |
| Line 1 (2I5, 60A1) | |
|---|---|
| IL | Law number |
| ITYPE | 290 |
| COMMENT | Any comment (up to 60 characters) that will be reproduced on the output listing. |
| Line 1 (1I5) | |
|---|---|
| NTEMP | number of temperatures at which CREEX, CREPA, SIGO and CADE parameters are given (see hereafter) |
| Line 1 (7G10.0) | |
|---|---|
| DGRAIN | mean grain size |
| SLIDE | grain viscosity parameter $\dot{\varepsilon}_{c}^{e}/\varepsilon_{B}$ |
| CDIFF | boundary diffusivity |
| ATVOL | atomic volume |
| ACTIV | activation energy |
| FNUC | nucleation parameter |
| CADEN | cavities density for nucleation (not used because of temperature dependence of CADE, see hereunder) |
| Line 2 (5G10.0) | |
| PSI | cavities angle |
| AINI | initial cavity size |
| BINI | initial cavity distance |
| DLIM | rupture criterion (a/b) |
| CDMAX | factor of the cavities density for nucleation |
if NTEMP = 1
| Line 3 (4G10.0) | |
|---|---|
| CREEX | creep exponent n |
| CREPA | creep parameter B |
| SIGO | normalisation stress |
| CADE | cavities density for nucleation |
| Line 4 (2G10.0) | |
| AKP | penalty coefficient on the contact pressure $K_P$ |
| AKTAU | penalty coefficient on the shear frictional stress $K_{\tau}$ |
if NTEMP > 1
| Line 3 (5G10.0) - Repeat NTEMP times | |
|---|---|
| TEMP | temperature (of the solid) |
| CREEX | creep exponent n at temperature TEMP |
| CREPA | creep parameter B at temperature TEMP |
| SIGO | normalisation stress at temperature TEMP |
| CADE | cavities density for nucleation |
| Line 3 + NTEMP (2G10.0) | |
| AKP | penalty coefficient on the contact pressure $K_P$ |
| AKTAU | penalty coefficient on the shear frictional stress $K_{\tau}$ |
3
| SIG(1) | normal contact pressure |
| SIG(2) | tangent contact stress |
| SIG(3) | meaningless |
17
These are the state variables related to the law, they are the first ones printed. After them, you find the state variables related to the contact geometry, their meaning is explained in the element section;
| 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 thermal contact |
| Q(2) | interface temperature |
| Q(3) | meaningless |
| Q(4) | accumulated damage d |
| Q(5) | accumulated interface sliding u |
| Q(6) | accumulated interface separation $\delta$ |
| Q(7) | cavity volume growth rate $\dot{V}$ |
| Q(8) | equivalent strain |
| Q(9) | equivalent strain rate |
| Q(10) | total cavity volume V |
| Q(11) | actual cavity density N |
| Q(12) | actual cavity size a |
| Q(13) | actual cavity distance b |
| Q(14) | mean stress |
| Q(15) | equivalent stress |
| Q(16) | total normal contact pressure |
| Q(17) | total tangent contact stress |