*MAT_181 (SIMPLIFIED_RUBBER/FOAM)

LS-DYNA Input Interface KeywordDefines a rubber and foam material with uniaxial tensile/compression test results as input curve. This material can be used with solid elements only.

Format

(1) (2) (3) (4) (5) (6) (7) (8)
*MAT_181 or *MAT_SIMPLIFIED_RUBBER/FOAM
mat_ID ρ i K   G      
Length Wide Thick Table_ID Tension      
Optional card 1: unloading behavior
(1) (2) (3) (4) (5) (6) (7) (8)
Fct_unl Hys Shape          

Definition

Field Contents SI Unit Example
mat_ID Material identifier.

(Integer)
ρ i Poisson's ratio.

(Real)

 [ kg m 3 ]
K Bulk modulus.

(Real)

 [ Pa ]
G Shear modulus.

(Real)

 [ Pa ]
Length Specimen gauge length.

(Real)

 [ m ]
Wide Specimen gauge width.

(Real)

 [ m ]
Thick Specimen gauge thickness.

(Real)

 [ m ]
Table_ID Curve or table ID defining the force versus gauge length and for the different strain rate value defined in the table.

(Integer)

  
Tension Unloading rate effects option flag.
= 0 (Default)
Unloading follows the quasi-static unloading curve.
= 1
Unloading follows the loading strain rate dependent curves and the unloading curve is not used.
= -1
Unloading in tension follows the quasi static unloading curve; Unloading in compression follow the loading strain rate dependent curves.

(Integer)

  
Fct_unl Unloading curve ID.

(Integer)

  
Hys Hysteresis unloading factor. Ignore if, unloading function is used.

0.0 ≤ Hys ≤ 1.0

Default = 0 (Real)

  
Shape Shape factor. Ignored if, unloading function is used.

Default = 1.0 (Real)

  

Comments

  1. This keyword maps to /MAT/LAW70 (FOAM_TAB) for foam, and /MAT/LAW88 for the hyperelastic materials.
  2. The option “_TITLE” can be added to the end of this keyword. When “_TITLE” is included, an extra 80 characters long line is added after the keyword input line which allows an entity title to be defined.