Table of Contents

IRSTH

Description

Elastic-visco-plastic constitutive law with thermal effects for solid elements at variable temperature (to check before use, A-M. HABRAKEN, june 91).

The model

Coupled thermo-mechanical analysis of elastic-visco-plastic solids undergoing large strains

Files

Prepro: LIRSTH.F
Lagamine: IRSC2E.F, IRSC2A.F, IRSC2G.F

Availability

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

Input file

Parameters defining the type of constitutive law

Line 1 (2I5, 60A1)
ILLaw number
ITYPE 240
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
NINTV number of sub-steps used to integrate numerically the constitutive equation in a time step
IENTH0 to use the classical formulation of the heat problem
1 to use the enthalpy formulation of the heat problem

Real parameters

2 lines repeated NTEMP times

Line 1 (7G10.0)
Ttemperature
EYOUNG's elastic modulus at temperature T
ANUPOISSON's ratio at temperature T
ALPHAthermal expansion coefficient ($\alpha$) at temperature T
ANstrain rate exponent (n) at temperature T
Bstrain rate coefficient (B) at temperature T
AMhardening exponent (m) at temperature T
Line 2 (10X, 4G10.0)
H1hardening coefficient ($H_1$) at temperature T
AQrecovery exponent (q) at temperature T
H2recovery coefficient ($H_2$) at temperature T
AKOinitial yield limit ($K_o$) at temperature T

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

4

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
Q(2) current yield limit in tension, its initial value is $K_o$
Q(3) hydrostatic stress ($\sigma_m$)
Q(4) difference between the current temperature and the initial temperature