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laws:bodath
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BODATH
Description
Bodner elastic-visco-plastic constitutive damage law with thermal effects for solid elements at variable temperature.
The model
Coupled thermo-mechanical analysis with damage of elastic-visco-plastic solids undergoing large strains.
Files
Prepro: LBODAT.F
Lagamine: BODC2E.F, BODC2A.F, BODC3D.F
Availability
| Plane stress state | NO |
| Plane strain state | YES |
| Axisymmetric state | YES |
| 3D state | YES |
| Generalized plane state | NO |
Input file
Parameters defining the type of constitutive law
| Line 1 (2I5, 60A1) | |
|---|---|
| IL | Law number |
| ITYPE | 246 |
| COMMENT | Any comment (up to 60 characters) that will be reproduced on the output listing. |
Integer parameters
| Line 1 (9I5) | |
|---|---|
| NTEMP | number of temperatures at which material data are given |
| NINTV | number of sub-steps used to integrate numerically the constitutive equation in a time step |
| IFRAC | usefulness actually |
| ISDOT | >0 <0 |
Real parameters independent of the temperature
| Line 1 (7G10.0) | |
|---|---|
| E | YOUNG's elastic modulus |
| ANU | POISSON's ratio |
| D0 | assumed limiting plastic-shear strain rate |
| D1 | maximum of directional hardness |
| RK1 | maximum of istropic hardness |
| RM1 | hardening exponent of isotropic hardness |
| RM2 | hardening exponent of directional hardness |
| Line 2 (4G10.0) | |
| R1 | recovery exponent of isotropic hardness |
| R2 | recovery exponent of directional hardness |
| ALPHA | thermal expansion coefficient ($\alpha$) |
| COEF | TAYLOR QUINNEY's coefficient |
Real parameters dependent of the temperature
Repeat NTEMP times
| Line 1 (6G10.0) | |
|---|---|
| TEMPE | temperature |
| RKO | initial isotropic hardness ($K_o$) at temperature T |
| RK2 | minimum or stable isotropic hardness ($K_o$) at temperature T |
| A1 | recovery coefficient of isotropic hardness at temperature T |
| A2 | recovery coefficient of directional hardness at temperature T |
| RN | strain rate sensitivity coefficient (n) at temperature T |
Real parameters related to the damage model
| Line 1 (7G10.0) | |
|---|---|
| A | coefficient of stress function in the damage model (A) |
| S | exponent of stress function in the damage model (S) |
| THOLD | stress threshold for damage onset |
| R | exponent of equivalent plastic strain rate |
| TAUCO | ratio of deviatoric to volumetric damage |
| BETA | constant in the triaxial stress function |
| DSMAX | failure value of deviatoric damage |
Stresses
Number of stresses
6 for the 3D state
4 for the other cases
Meaning
The stresses are the components of CAUCHY stress tensor in global (X,Y,Z) coordinates.
For the 3-D state:
| SIG(1) | $\sigma_{XX}$ |
| SIG(2) | $\sigma_{YY}$ |
| SIG(3) | $\sigma_{ZZ}$ |
| SIG(4) | $\sigma_{XY}$ |
| SIG(5) | $\sigma_{XZ}$ |
| SIG(6) | $\sigma_{YZ}$ |
For the other cases:
| SIG(1) | $\sigma_{XX}$ |
| SIG(2) | $\sigma_{YY}$ |
| SIG(3) | $\sigma_{XY}$ |
| SIG(4) | $\sigma_{ZZ}$ |
State variables
Number of state variables
25 for the 3D state
23 for the other cases
List of state variables
| Q(1) | = element thickness (t) in plane stress state = 1 in plane strain state = circumferential strain rate $\dot{\varepsilon_\theta}$ in axisymmetric state = 0 in 3D state = element thickness (t) in generalized plane state |
| Q(2) | current equivalent stress in tension |
| Q(3) | current isotropic hardness, its initial value is KO |
| Q(4) | equivalent directional hardness |
| Q(5)-Q(N) | components of directional hardness (N = 10 for 3D state and N = 8 for other cases) |
| Q(N+1) | equivalent strain |
| Q(N+2) | deviatoric damage |
| Q(N+3) | volumetric damage |
| Q(N+4) | PUISB |
| Q(N+5) | PUISB*DELTAT (its final value is calculated in THNL2 or THNL3) |
| Q(N+6) | RHO * C (calculated in THNL2 or THNL3) |
| Q(N+7)-Q(N+12) | fracture criteria (not programmed) |
| Q(N+13) | NINTV |
| Q(N+14) | deviatoric damage rate |
| Q(N+15) | 0 if d < DSMAX 1 if d > or = DSMAX |
laws/bodath.txt · Last modified: 2020/08/25 15:46 (external edit)
