/MAT/LAW23 (PLAS_DAMA)
Block Format Keyword This law models an isotropic elastic plastic material and combines JohnsonCook material model with a generalized damage model. The law is applicable only for solid elements.
Format
(1)  (2)  (3)  (4)  (5)  (6)  (7)  (8)  (9)  (10) 

/MAT/LAW23/mat_ID/unit_ID or /MAT/PLAS_DAMA/mat_ID/unit_ID  
mat_title  
${\rho}_{i}$  
E  $\nu $  
a  b  n  ${\epsilon}_{p}^{max}$  ${\sigma}_{\mathrm{max}\text{}0}$  
c  ${\dot{\epsilon}}_{0}$  ICC  
${\epsilon}_{dam}$  E_{t} 
Definition
Field  Contents  SI Unit Example 

mat_ID  Material
identifier. (Integer, maximum 10 digits) 

unit_ID  Unit Identifier. (Integer, maximum 10 digits) 

mat_title  Material
title. (Character, maximum 100 characters) 

${\rho}_{i}$  Initial
density. (Real) 
$\left[\frac{\text{kg}}{{\text{m}}^{\text{3}}}\right]$ 
E  Young's
modulus. (Real) 
$\left[\text{Pa}\right]$ 
$\nu $  Poisson's
ratio. (Real) 

a  Plasticity yield stress 
should be strictly positive. (Real) 
$\left[\text{Pa}\right]$ 
b  Plasticity hardening
parameter. (Real) 

n  Plasticity hardening
exponent. 3 (Real) 

${\epsilon}_{p}^{max}$  Failure plastic
strain. Default = 10^{30} (Real) 

${\sigma}_{\mathrm{max}\text{}0}$  Plasticity maximum
stress. Default = 10^{30} (Real) 
$\left[\text{Pa}\right]$ 
c  Strain rate coefficient.
Default = 0.00 (Real) 

${\dot{\epsilon}}_{0}$  Reference strain
rate. If $\dot{\epsilon}\le {\dot{\epsilon}}_{0}$ , no strain rate effect. (Real) 
$\left[\frac{\text{1}}{\text{s}}\right]$ 
ICC  Strain rate computation
flag. 5
(Integer) 

${\epsilon}_{dam}$  Damage model starts at
${\epsilon}_{dam}$
. Default = 0.15 (Real) 

E_{t}  Softening damage slope (
$E<{E}_{t}\le 0$
). Default = 0.00 (Real) 
$\left[\text{Pa}\right]$ 
Example (Aluminum)
#RADIOSS STARTER
#12345678910
/UNIT/1
unit for mat
g mm ms
#12345678910
# 2. MATERIALS:
#12345678910
/MAT/LAW23/1/1
Alu
# RHO_I
.0027
# E nu
70000 .3
# a b n Eps_max sig_max0
100 0 1 .2 100
# c EPS_0 ICC
0 0 0
# EPS_dam E_t
.1 2000
#12345678910
#ENDDATA
/END
#12345678910
Comments
 The damage law is applied to the stress tensor ${\sigma}_{ij}$ and damage occurs in tension, compression and shear.
 The input is the same as material law (/MAT/LAW22 (DAMA)).
 The plasticity hardening exponent n must be less than one.
 When ${\epsilon}_{p}$ reaches ${\epsilon}_{p}^{max}$ , in one integration point, then the solid element is deleted.
 ICC is a flag of the strain
rate effect on material maximum stress
${\sigma}_{\mathrm{max}}$
.
$\sigma ={\sigma}_{y}\left(1+c\mathrm{ln}\left(\frac{\dot{\epsilon}}{{\dot{\epsilon}}_{o}}\right)\right)$ $\sigma ={\sigma}_{y}\left(1+c\mathrm{ln}\left(\frac{\dot{\epsilon}}{{\dot{\epsilon}}_{o}}\right)\right)$ ${\sigma}_{\mathrm{max}}={\sigma}_{\mathrm{max}0}\left(1+c\mathrm{ln}\left(\frac{\dot{\epsilon}}{{\dot{\epsilon}}_{o}}\right)\right)$ ${\sigma}_{\mathrm{max}}={\sigma}_{\mathrm{max}0}$