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laws:vmvp
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Table of Contents
VMVP
Von Mises Visco-Plastic.
Description
3D isotropic viscoplastic damage law that enables the modeling of non-classical creep responses via Graham-Walles and a modified activation function-Norton viscosity function.
Numerical model
This law was implemented in the context of C.Rojas-Ulloa's PhD. project on the modeling of the non-classical long-term creep response of Incoloy 800H (see (C.Rojas-Ulloa et al., 2024) for more details). It is based in the law implemented by Hélène Morch (CHAB), a viscoplastic damage law combines the von Mises yield criterion with a Norton viscosity function, a complex backstress formulation, and Kachanov-Lemaitre creep-fatigue damage laws). VMVP includes
Input file
Parameters defining the type of constitutive law
| Line 01; format (2I5, 60A1) | |
|---|---|
| IL | Law number |
| ITYPE | 271 |
| COMMENT | Any comment (up to 60 characters) that will be reproduced on the output listing |
Integer parameters
| Line 02; format (9I5) | ||
|---|---|---|
| 1:5 | TID | =1 if parameters are given for linear interpolation at different temperatures = 0 if not |
| 6:10 | ntemp | if TID=1, ntemp defines the number of temperatures at which parameters are given |
| 11:15 | ianisoth | =1 if anisothermal loadings = 0 otherwise |
| 16:20 | MAXIT | =maximum number of Newton-Raphson iterations within the colaw (25 default) |
| 21:25 | nintv | =Number of sub-intervals (substeps); if 0, no substeps |
| 26:30 | ilcf | indicator for low-cycle fatigue |
| 31:35 | mat_interp | indicator for interpolation method (1$\leq$mat_interp$\leq$5) for material parameters $(E, \nu)$ |
| 36:40 | tdilc_interp | indicator for interpolation method (1$\leq$mat_interp$\leq$5) for temp. dilatation coefficient |
| 41:45 | iso_interp | indicator for interpolation method (1$\leq$mat_interp$\leq$5) for isotropic hardening parameters $(b, Q)$ |
| Line 03; format (10I5) | ||
| 1:5 | nAFX | Number of Armstrong-Fredericks equations used to define the back-stress $\underline{X}$ (minimum value=1) |
| 6:10 | NAFC | Number of Armstrong-Fredericks equations taking into account cyclic hardening |
| 11:15 | NAFY | Number of Armstrong-Fredericks equations taking into account evolution of the mean stress |
| 16:20 | iarrh | ID for interpolation method of AD equations |
| 21:25 | ivp | ID for type of viscoplastic law 1=Norton law (after CHAB); 2=Graham-Walles; 4=AFN |
| 26:30 | vpinterp | ID for interpolation method for viscoplastic law parameters. if ivp=2, vpinterp defines the number of Graham-Walles equations |
| 31:35 | type_dam | ID for damage type. 0=no damage; 1=uncoupled damage; 3=semi-coupled damage; 4=fully-coupled damage(not working yet) |
| 36:40 | idam | ID for damage law. 1 = Kachanov(creep) + Lemaitre(fatigue) (after CHAB); 2 = IfW (PhD. thesis from Narayana K. Karthik, RWTH Aachen university) |
| 41:45 | dam_interp | ID for interpolation of damage law parameters |
| 46:50 | daminit | ID for damage initiation criterion |
Real parameters
case TID = 0
| Line 04 | format | ||
|---|---|---|---|
| 1:$x$ | $E$ | Young modulus (MPa) | after mat_interp |
| Line 05 | … | ||
| 1:$x$ | $\nu$ | Poisson ratio (-) | after mat_interp |
| Line 06 | … | ||
| 1:$x$ | $\alpha$ | Thermal dilatation coefficient (m/K) | after mat_interp |
| Line 07 | … | ||
| 1:$x$ | $\sigma_y$ | Yield stress (MPa) | after iso_interp |
| $x$+1:$x$+10 | $b$ | Hardening saturation rate (-) | 1G10.0 |
| $x$+11:$x$+20 | $Q$ | Hardening saturation value (MPa) | 1G10.0 |
| Kinematic hardening (Armstrong-Frederick) Line 08:$\mathbf{m}$ | … | ||
| –> case iarrh=0; repeat for i=1,nAFX | |||
| 1:10 | $C_i$ | Swift-type hardening term (MPa) | 1G10.0 |
| 11:20 | $\gamma_i (-)$ | Static recovery term (-) | 1G10.0 |
| 21:30 | $b_i$ | Dynamic recovery term (-) | 1G10.0 |
| 31:40 | $r_i$ | Dynamic recovery exponent (-) | 1G10.0 |
| –> case iarrh=1; repeat for i=1,nAFX | |||
| 1:10 | $C_i (-)$ | Swift-type hardening term (MPa) | 1G10.0 |
| 11:20 | $A_{\gamma_{i}}$ | Static recovery term; single Arrhenius fit: $\gamma_i(T)=A_{\gamma_{i}}\cdot[1-B_{\gamma_{i}}\cdot exp(\frac{T}{C_{\gamma_{i}}})]$ | 1G10.0 |
| 21:30 | $B_{\gamma_{i}}$ | 1G10.0 | |
| 31:40 | $C_{\gamma_{i}}$ | 1G10.0 | |
| 41:50 | $b_i (-)$ | Dynamic recovery term (-) | 1G10.0 |
| 51:60 | $r_i (-)$ | Dynamic recovery exponent (-) | 1G10.0 |
| –> case iarrh=2; repeat for i=1,nFA Line 07$+2*i-1$ |
|||
| 1:10 | $A_{C_{i}}$ | Swift-type hardening term (MPa); single Arrhenius fit: $C_i(T)=A_{C_{i}}\cdot[1-B_{C_{i}}\cdot exp(\frac{T}{C_{C_{i}}})]$ | 1G10.0 |
| 11:20 | $B_{C_{i}}$ | 1G10.0 | |
| 21:30 | $C_{C_{i}}$ | 1G10.0 | |
| 31:40 | $A_{\gamma_{i}}$ | Static recovery term; single Arrhenius fit: $\gamma_i(T)=A_{\gamma_{i}}\cdot[1-B_{\gamma_{i}}\cdot exp(\frac{T}{C_{\gamma_{i}}})]$ | 1G10.0 |
| 41:50 | $B_{\gamma_{i}}$ | 1G10.0 | |
| 51:60 | $C_{\gamma_{i}}$ | 1G10.0 | |
| Line 07$+2*i$ | |||
| 1:10 | $A_{b_{i}}$ | Dynamic recovery term (-); single Arrhenius fit: $b_i(T)=A_{b_{i}}\cdot[1-B_{b_{i}}\cdot exp(\frac{T}{C_{b_{i}}})]$ | 1G10.0 |
| 11:20 | $B_{b_{i}}$ | 1G10.0 | |
| 21:30 | $C_{b_{i}}$ | 1G10.0 | |
| 31:40 | $r_i$ | Dynamic recovery exponent (-) | 1G10.0 |
| Cyclic hardening (mean stress evolution) Line $\textbf{m+1}$:$\textbf{n}$ | … | ||
| –> case iarrh=0 or iarrh=1; repeat for $j$=1,nAFC | |||
| 1:10 | $D_{\gamma_{j}}$ | Cyclic hardening parameter (-) | 1G10.0 |
| 11:20 | $a_{\gamma_{j}}$ | Strain memory surface parameter (-) | 1G10.0 |
| 21:30 | $b_{\gamma_{j}}$ | Strain memory surface parameter (-) | 1G10.0 |
| 31:40 | $c_{\gamma_{j}}$ | Strain memory surface parameter (-) | 1G10.0 |
| –> case iarrh=2; Single Arrhenius; repeat for $j$=1,nAFC Line $\textbf{n+1}$:$\textbf{o}$ |
|||
| 1:10 | $A_{D_{\gamma_{j}}}$ | Cyclic hardening parameter (-); single Arrhenius fit: $D_{\gamma_{j}}(T)=A_{D_{\gamma_{j}}}\cdot[1-B_{D_{\gamma_{j}}}\cdot exp(\frac{T}{C_{D_{\gamma_{j}}}})]$ | 1G10.0 |
| 11:20 | $B_{D_{\gamma_{j}}}$ | 1G10.0 | |
| 21:30 | $C_{D_{\gamma_{j}}}$ | 1G10.0 | |
Other things
| Interpolation methods included within VMVP: | |
|---|---|
| 1 | Unique value, no interpolation |
| 2 | Single Arrhenius fit $P(T)=A_P\cdot[1-B_P\cdot exp(\frac{T}{C_P}]$ Parameters $A_P$, $B_P$ & $C_P$ are introduced in format 3G10.0 |
| 3 | Double Arrhenius fit $P(T)=A_P\cdot[1-B_P\cdot exp(\frac{T}{C_P} )] - D_P\cdot exp(\frac{T}{E_P})]$ Parameters $A_P$, $B_P$, $C_P$, $D_P$ & $E_P$ are introduced in format 5G10.0 |
| 4 | 3 deg. polynomial fit $P(T)=A_P\cdot[1 - B_P\cdot(T-T_0) + C_P\cdot(T-T_0)^2 - D_P\cdot(T-T_0)^3]$ Parameters $A_P$, $B_P$, $C_P$, $D_P$ & $T_0$ are introduced in format 4G10.0 |
| List of state variables | |
|---|---|
| Q(1) | Equiv. plastic (creep) strain (-) |
| Q(2) | Equiv. plastic (creep) strain rate $(s^{-1})$ |
| Q(3) | Equiv. thermal strain (-) |
| Q(4:9) | Plastic strain vector (-) |
| Q(10:15) | Total strain vector (-) |
| Q(16) | Isotropic/cyclic hardening R (MPa) |
| Q(17) | Plastic memory surface radius (-) |
| Q(18:23) | Plastic memory surface center $\zeta$ |
| Q(24) | Total accumulated damage |
| Q(25) | Accumulated creep damage |
| Q(26) | Accumulated fatigue damage |
| Q(27) | Accumulated plastic energy $w_D$ |
| Q(28:28+6$\times$nAFX-1) | Kinematic hardening components $\underline{X}$ |
laws/vmvp.1731422873.txt.gz · Last modified: 2024/11/12 15:47 by carlos
