Table of Contents

LEV-T

Description

Elasto-viscoplastic constitutive law with thermal effects for solid elements at variable temperature

The model

Coupled thermo-mechanical analysis of elasto-viscoplastic isotropic element undergoing large strains.

Files

Prepro: LLEVT.F
Lagamine: LEVT2D.F,

Availability

Plane stress stateNO
Plane strain state YES
Axisymmetric state YES
3D state NO
Generalized plane state NO

Input file

Parameters defining the type of constitutive law

Line 1 (2I5, 60A1)
ILLaw number
ITYPE 230
COMMENT Any comment (up to 60 characters) that will be reproduced on the output listing.

Integer parameters

Line 1 (3I5)
NTEMPnumber of temperature at which material data are given
IALG0 if $\alpha$ is given
1 if $\int{\alpha dT}$ is given
METK 0 $\dot{\lambda}$ function $\hat{D}_{eq}$ and analytical compliance matrix
1 compliance matrix computed by perturbation

Real parameters

if NTEMP $\neq$ 0

Line 1 (7G10.0) - Repeat NTEMP times
T temperature
EYOUNG's elastic modulus at temperature T
ANUPOISSON's ratio at temperature T
ALPHAthermal expansion coefficient ($\alpha$) or $\int{\alpha dT}$ at temperature (see IALG)
$A_{c}$ parameter for $\sigma- \dot{\varepsilon}_{\theta}$ relation at temperature T
$A_{m}$ parameter for $\sigma- \dot{\varepsilon}_{\theta}$ relation at temperature T
$\hat{\sigma}_{eq} = A_{c} \hat{D}_{eq}^{A_{m}}$
CTQ Taylor-Qinney's coefficient (q) at temperature T if NTEMP = 0.

if NTEMP = 0

Line 1 (5G10.0)
$E_{0}$E = $E_{0}(1-exp(-B_{E}*T))$
$\nu_{0}$$\nu= \nu_{0}exp(B_{\nu}*T)$
$\alpha_{0}$$\alpha= \alpha_{0}exp(B_{\alpha}/T)$
$A_{c0}$$A_{c}= A_{c0}exp(B_{A_{c}}/T)$
$A_{m0}$$A_{m}= A_{m0}(1-exp(-B_{A_{m}}*T))$
Line 2 (5G10.0)
$B_{E}$To check before use (June 91 A-M.HABRAKEN)
$B_{\nu}$
$B_{\alpha}$
$B_{A_{c}}$
$B_{A_{m}}$

Stresses

Number of stresses

4 (for plane state)

Meaning

The stresses are the components of CAUCHY stress tensor in global (X,Y,Z) coordinates.

SIG(1)$\sigma_{XX}$
SIG(2)$\sigma_{YY}$
SIG(3)$\sigma_{XY}$
SIG(4)$\sigma_{ZZ}$

State variables

Number of state variables

7

List of state variables

Q(1) circumferential strain rate $\dot{\varepsilon_\theta}$ in axisymmetric state
1 in plane strain state
Q(2) current yield limit in tension
Q(3) 0 if the current state is elastic
1 if the current state is elasto-plastic
Q(4) equivalent plastic strain $\overline{\varepsilon}^{p}$
Q(5) plastic work per unit volume
Q(6) part of the dissipated power converted into heat
Q(7) initial temperature