/MAT/LAW33 (FOAM

Block Format Keyword

/MAT/LAW33 - Visco-Elastic Plastic Foam Material

Description

This law models a visco-elastic plastic foam material. This law is applicable only for solid elements and is typically used to model low density, closed cell polyurethane foams such as impact limiters.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/MAT/LAW33/mat_ID/unit_ID or /MAT/FOAM_PLAS/mat_ID/unit_ID
mat_title

E		Ka	fct_IDf	Fscalecrv
P0
A		B		C

Read only if Ka = 1

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
E1		E2		Et

Field	Contents	SI Unit Example
mat_ID	Material identifier (Integer, maximum 10 digits)
unit_ID	Optional unit identifier (Integer, maximum 10 digits)
mat_title	Material title (Character, maximum 100 characters)
	Initial density (Real)
E	Young’s modulus (Real)
Ka	Analysis type flag (Integer) = 0: the skeletal behavior before yield is elastic = 1: the skeletal behavior before yield is visco-elastic
fct_IDf	Yield stress vs. volumetric strain curve function identifier (Integer)
Fscalecrv	Stress in yield curve scale factor Default = 1.0 (Real)
P0	Initial air pressure (Comment 3) (Real)
	Ratio of foam to polymer density (Real)
	Initial volumetric strain (Real)
A	Yield parameter (Real)
B	Yield parameter (Real)
C	Yield parameter (Real)
E1	Coefficient for Young’s modulus update (Real)
E2	Coefficient for Young’s modulus update (Real)
Et	Tangent modulus (Real)
	Viscosity coefficient in pure compression (Real)
	Viscosity coefficient in pure shear (Real)

#RADIOSS STARTER

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

/UNIT/1

unit for mat

Mg mm s

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

#- 2. MATERIALS:

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

/MAT/FOAM_PLAS/1/1

Foam

# RHO_I

2E-10

# E Ka fct_IDf Fscale_crv

200 1 0 1

# P0 Phi Gamma_0

0 0 0

# A B C

1E30 0 0

# E1 E2 Et nu_comp nu_shear

0 0 2 2E27 1E27

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

#ENDDATA

/END

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

1.	If fct_IDf = 0, then

Where, is the volumetric strain:

2.	If fct_IDf ≠ 0, vs. is read from input of the curve number fct_IDf. The curve can be defined for tensile () and compression (). Stress is positive anytime.