/MAT/LAW65 (ELASTOMER)

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/MAT/LAW65/mat_ID/unit_ID or /MAT/ELASTOMER/mat_ID/unit_ID
mat_title
${\rho }_{i}$
E $\upsilon$ ${\epsilon }_{p}^{max}$
Nrate Fsmooth Fcut
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
fct_IDld fct_IDul Fscalestress $\stackrel{˙}{\epsilon }$

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)

$\left[\text{Pa}\right]$
$\upsilon$ Poisson's ratio.

(Real)

${\epsilon }_{p}^{max}$ Failure plastic strain.

(Real)

Default = 50 (Integer)

Fsmooth Smooth strain rate flag.
= 0 (Default)
No strain rate filtering.
= 1
Strain rate filtering.

(Integer)

Fcut Cutoff frequency for strain rate filtering.

Default = 1030 (Real)

$\text{[Hz]}$

(Integer)

(Integer)

Fscalestress Stress scale factor.

Default = 1.0 (Real)

$\left[\text{Pa}\right]$
$\stackrel{˙}{\epsilon }$ Strain rate.

Default = 1.0 (Real)

$\left[\frac{\text{1}}{\text{s}}\right]$

Example (Nitinol)

#RADIOSS STARTER
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/UNIT/1
unit for mat
kg                  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/LAW65/1/1
nitinol-like material
#              RHO_I
6E-6
#                 E0                  NU             EPS_max
50                  .3                   0
#    Nrate   Fsmooth                Fcut
1         1                   0
#FUNC_IDld FUNC_IDul       FSCALESTRESS             EPS_rate
3         4                   1                   0
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#-  3. FUNCTIONS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/3
#                  X                   Y
0                   0
.0085                 .35
.0575                 .55
.077               1.262
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/4
#                  X                   Y
0                   0
.0055                .199
.0502                 .25
.077               1.245
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#ENDDATA
/END
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|


1. The law is defined by pairs of true stress-true strain functions for loading and unloading at specified strain rates. Each of the curves should begin with point (0,0) and increase monotonically. Each unloading curve should lie below the loading curve for corresponding strain rate.
2. The loading/unloading curve with the higher strain rate ( ${\stackrel{˙}{\epsilon }}_{2}$ ) should lie above the curve with lower strain rate ( ${\stackrel{˙}{\epsilon }}_{1}$ ). The curves between ${\stackrel{˙}{\epsilon }}_{2}$ and ${\stackrel{˙}{\epsilon }}_{1}$ are interpolated linearly for intermediate strain rates. Curves are extrapolated for strain rates higher than maximum specified strain rate. It is advised to duplicate the last curves twice to avoid instability for high strain rates.
6. When ${\epsilon }_{p}$ reaches ${\epsilon }_{p}^{max}$ in one integration point, then based on the element type: