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laws:lvmcq4
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LVMCQ4
Description
Von Mises type constitutive law for 3D shell (COQJ4) element numerically integrated on the thickness.
The model
This law is only used for mechanical analysis of elastoplastic isotropic hardening. Numerical integration on the thickness is used.
Files
Prepro: LVMCQ4.F
Lagamine: CQ4VMS.F
Input file
Parameters defining the type of constitutive law
| Line 1 (2I5, 60A1) | |
|---|---|
| IL | Law number |
| ITYPE | = 31 |
| COMMENT | Any comment (up to 60 characters) that will be reproduced on the output listing |
Integer parameters
| Line 1 (5I5) | |
|---|---|
| NPI | number of integration points across the thickness ( $\leq$ 10 ) |
| IND | index of the thickness variable |
| = 0 the thickness is variable during deformation | |
| = 1 it is constant during deformation | |
| = -1 incompressible | |
| NPO | number of points to define the uniaxial constitutive law ($\geq$ 0) |
| = 0 → bilinear | |
| = n → multilinear | |
| METH | = the method used to calculate the IP on thickness |
| = 0 → GAUSS | |
| = 1 → LOBATTO | |
| = 2 → NEWTON-COTE | |
| NINTV | number of sub-interval used to integrate the law |
Real parameters
Global Data
| Line 1 (2G10.0) | |
|---|---|
| E | Young Modulus |
| ANU | Poisson's coefficient |
Uniaxial Constitutive Law
For NPO = 0
| Line 2 (2G10.0) | |
|---|---|
| SY | Initial yield stress |
| ET | The tangent modulus (must be different than E) |
For NPO $\neq$ 0
| Line 2 - Repeated N times (2G10.0) | |
|---|---|
| $\sigma_i$ | the value of stress at the considered point |
| $\varepsilon$ | the value of strain at the considered point |
Results
Stresses
| SIG(1) | $N_x$, normal effort in the local X‑direction |
| SIG(2) | $N_y$, normal effort in the local Y‑direction |
| SIG(3) | $N_{xy}$, normal effort in the local X-Y plan |
| SIG(4) | $M_x$, moment associated to the local X‑direction |
| SIG(5) | $M_y$, moment associated to the local Y‑direction |
| SIG(6) | $M_{xy}$, moment associated to the local X-Y plan |
State variables
| Q(1) | thick, the actual thickness for this IP. |
| Q(2) | $\sigma_y^e$, the equivalent VM type stress integrated through the thickness of this IP |
| Q(3) | Yield, index of stress state for this IP |
| = 0, the stress state in this IP is elastic. | |
| = 1, it is elastoplastic. | |
| Repeat NPI times ($K = 3 + (IPI-1)*6$) | |
|---|---|
| Q(K+1) | $\sigma_y$, the yield stress at this IP in the thickness. |
| Q(K+2) | Yield, index of stress state for this IP in the thickness. |
| Q(K+3) | $\varepsilon_{ep}^p$, equivalent plastic strain at this IP in the thickness. |
| Q(K+4) | $\sigma_{11}$, the local stress at this IP in the thickness. |
| Q(K+5) | $\sigma_{22}$, idem. |
| Q(K+6) | $\sigma_{12}$, idem. |
the total number of state variables is equal to $3 + NPI*6$
laws/lvmcq4.txt · Last modified: 2020/08/25 15:46 (external edit)
