# *MAT_034 (FABRIC)

LS-DYNA Input Interface KeywordDefines an orthotropic elastic material with softening in compression.

## Format

(1) (2) (3) (4) (5) (6) (7) (8)
*MAT_034 or *MAT_FABRIC
mat_ID ${\rho }_{i}$ E1 E2 v12
G12 G23 G32 RE
AOPT FLC FAC FORM
A1 A2 A3
V1 V2 V3 BETA
FUNC_1 FUNC_2 FUNC_3 FUNCUN_1 FUNCUN_2 FUNCUN_3
Read if FORM = 14 or -14
(1) (2) (3) (4) (5) (6) (7) (8)
FUNC_1 FUNC_2 FUNC_3 FUNCUN_1 FUNCUN_2 FUNCUN_3

## Definition

Field Contents SI Unit Example
mat_ID Material identifier.

(Integer)

${\rho }_{i}$ Initial density.

(Real)

$\left[\frac{\text{kg}}{{\text{m}}^{\text{3}}}\right]$
E1, E2 Young’s modulus in material directions 1 and 2.

E2=E1, if E2 is null or not defined.

(Real)

$\left[\text{Pa}\right]$
v12 Poisson’s ratio between directions 1 and 2.

Default = 0 (Real)

G12, G23, G32 Shear modulus in corresponding directions.

(Real)

$\left[\text{Pa}\right]$
RE Stiffness reduction in compression option.
= 0
No stiffness reduction in compression.
= 1
Stiffness reduction in compression.

(Integer)

FORM Membrane formulation.
= 14 or -14
Material is anisotropic.

Otherwise, material is linear orthotropic.

AOPT Material axis flag.
= 0 (Default)
Locally orthotropic axes defined by Node.
= 2
Globally orthotropic axes defined by Vector.
= 3
Locally orthotropic axes defined with element normal.
AOPT < 0
The absolute value |AOPT| is a coordinate system identifier which defines the orthotropic directions.

(Real)

FLC
> 0
Scaling coefficient for porous area.
< 0
Function number which determines scaling coefficient for porous area as function of time.

(Real)

FAC
< 0
Gas outflow velocity as function of absolute pressure inside of airbag.

(Real)

A1, A2, A3 Vector defining first orthotropy direction for AOPT = 2.

(Real)

V1, V2, V3 A vector which in combination with element normal defines the first orthotropy direction for AOPT = 3.

(Real)

BETA Material angle for AOPT = 3,0.

(Real)

$\left[\mathrm{deg}\right]$
FUNC_1 Loading curve for true stress versus true strain in material direction 1.

(Integer)

$\left[\text{Pa}\right]$
FUNC_2 Loading curve for true stress versus true strain in material direction 2.

(Integer)

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

(Integer)

$\left[\text{Pa}\right]$
FUNCUN_1 Unloading curve for true stress versus true strain in material direction 1.

(Integer)

$\left[\text{Pa}\right]$
FUNCUN_2 Unloading curve for true stress versus true strain in material direction 2.

(Integer)

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