/MAT/LAW82

Block Format Keyword

/MAT/LAW82 - Ogden Material

Description

This keyword defines the Ogden material. This law is compatible with solid and shell elements. In general it is used to model polymers and elastomers.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/MAT/LAW82/mat_ID/unit_ID
mat_title

N

. . . N values of (five per line)

. . . N values of (five per line)
D1		D2		D3
. . . N values of D (five per line)

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)
N	Order of the Ogden model (Integer, maximum 10 digits)
	Poisson’s ratio Default = 0.475 (Real)
	ith Parameter (i = 1,N) (Real)
	ith Parameter (i = 1,N) (Real)
Di	ith Parameter (i = 1,N) (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/LAW82/1/1

Rubber

# RHO_I

2E-9

# N NU

3 0

# Mu_i

1.061898 .0578289 .0159176

# Alpha_i

.428246 5.71269 -4.59726

# D_i

1E-4 0 0

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

#ENDDATA

/END

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

#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/LAW82/1/1

LAW82 RUBBER

# RHO_I

1E-9

# N NU

2 .495

# Mu_i

2 1

# Alpha_i

2 -2

# D_i

0 0

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

#ENDDATA

/END

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

1.	The strain energy density W is computed using the following equation:

with and

where, is the ith principal stretch.

2.	The Bulk Modulus is:

➢	If , then,

➢	If , the value D1 is modified to respect:

If and D1 = 0, then .

3.	To get a material without Poisson ratio effect, should be defined with a small value (1e-10).

4.	The ground shear modulus:

5.	Further explanation about this law can be found in “Non-Linear Elastic Deformations”, by R.W Ogden, Ellis Horwood, 1984.