/MAT/LAW23 (PLAS_DAMA)

Block Format Keyword This law models an isotropic elastic plastic material and combines Johnson-Cook 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 ${\stackrel{˙}{\epsilon }}_{0}$ ICC
${\epsilon }_{dam}$ Et

Definitions

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 = 1030 (Real)

${\sigma }_{\mathrm{max}\text{​}0}$ Plasticity maximum stress.

Default = 1030 (Real)

$\left[\text{Pa}\right]$
c Strain rate coefficient.
= 0
No strain rate effect.

Default = 0.00 (Real)

${\stackrel{˙}{\epsilon }}_{0}$ Reference strain rate.

If $\stackrel{˙}{\epsilon }\le {\stackrel{˙}{\epsilon }}_{0}$ , no strain rate effect.

(Real)

$\left[\frac{\text{1}}{\text{s}}\right]$
ICC Strain rate computation flag. 5
= 0 (Default)
Set to 1.
= 1
Strain rate effect on ${\sigma }_{\mathrm{max}}$ .
= 2
No strain rate effect on ${\sigma }_{\mathrm{max}}$ .

(Integer)

${\epsilon }_{dam}$ Damage model starts at ${\epsilon }_{dam}$ .

Default = 0.15 (Real)

Et Softening damage slope ( $-E<{E}_{t}\le 0$ ).

Default = 0.00 (Real)

$\left[\text{Pa}\right]$

Example (Aluminum)

#RADIOSS STARTER
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/UNIT/1
unit for mat
g                  mm                  ms
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#-  2. MATERIALS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/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
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#ENDDATA
/END
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

Comments

1. The damage law is applied to the stress tensor ${\sigma }_{ij}$ and damage occurs in tension, compression and shear.
2. The input is the same as material law (/MAT/LAW22 (DAMA)).
3. The plasticity hardening exponent n must be less than one.
4. When ${\epsilon }_{p}$ reaches ${\epsilon }_{p}^{max}$ , in one integration point, then the solid element is deleted.
5. ICC is a flag of the strain rate effect on material maximum stress ${\sigma }_{\mathrm{max}}$ .