/MAT/LAW57 (BARLAT3)

Block Format Keyword

/MAT/LAW57 - Barlat 3-Parameters Orthotropic Material

Description

This law describes plasticity hardening defined by a user function and can be used only with shell elements. This is an elasto-plastic orthotropic law for modeling anisotropic materials in forming processes especially aluminum alloys. This material law must be used with property set type /PROP/TYPE9 (SH_ORTH) or /PROP/TYPE10 (SH_COMP).

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/MAT/LAW57/mat_ID/unit_ID or /MAT/BARLAT3/mat_ID/unit_ID
mat_title

E
fct_IDE		Einf		CE
r00		r45		r90		Chard		m

fct_IDi		Fscalei

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)
	Poisson’s ratio (Real)
fct_IDE	Function identifier for the scale factor of Young modulus, when Young modulus is function of the plastic strain (Comment 11): Default = 0: in this case the evolution of Young depends on Einf and CE. (Integer)
Einf	Saturated Young’s modulus for infinitive plastic strain (Real)
CE	Parameter for Young’s modulus evolution (Real)
r00	Lankford parameter 0 degree Default = 1.0 (Real)
r45	Lankford parameter 45 degrees Default = 1.0 (Real)
r90	Lankford parameter 90 degrees Default = 1.0 (Real)
Chard	Hardening coefficient (Real) = 0: hardening is full isotropic model = 1: hardening uses the kinematic Prager-Ziegler model = between 0 and 1: hardening is interpolated between the two models
m	Barlat parameter Default = 6.0 (Real) = 8.0: for Face Centered Cubic (FCC) material = 6.0: for Body Centered Cubic (BCC) material
	Failure plastic strain Default = 1.0 x 1030 (Real)
	Tensile failure strain at which stress starts to reduce. Default = 1.0 x 1030 (Real)
	Maximum tensile failure damage strain at which the stress in element is set to zero. Default = 2.0 x 1030 (Real)
fct_IDi	Plasticity curves ith function identifier (Integer)
Fscalei	Scale factor for ith function Default set to 1.0 (Real)
	Strain rate for ith function (Real)

#RADIOSS STARTER

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

/UNIT/1

unit for mat

g 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/LAW57/1/1

Steel

# RHO_I

.008

# E NU

206000 .300000012

# fct_IDE E_INF CE

0 0 0

# r00 r45 r90 C_hard m

1.79 1.51 2.27 0 0

# EPSP_max EPS_T EPS_M

0 0 0

# fct_ID Fscale_i EPS_i

5 0 0

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

#- 3. FUNCTIONS:

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

/FUNCT/5

function_5

# X Y

0 157

.1 320

.5 480

1.2 600

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

#ENDDATA

/END

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

1.	The anisotopic yield criteria F for plane stress is defined by:

where,

is the yield stress

and

2.	Angles for Lankford parameters are defined with respect to orthotropic direction 1. The material constants a, c, h, and p are obtained from the three Lankford parameters:

Material constant p is calculated by solving:

3.	If the last point of the first (static) function equals 0 in stress, the default value of is set to the corresponding value of .

4.	If (plastic strain) reaches , in one integration point, the corresponding shell element is deleted.

5.	If the largest principal strain , the stress is reduced using the following relation:

6.	If , the stress is reduced to 0 (but the element is not deleted).

7.	The maximum number of curves is 10.

8.	If , the yield is interpolated between fn and fn-1.

9.	If , function f1 is used.

10.	Above , yield is extrapolated.

law57

11.	The evolution of Young’s modulus:

•	If fct_IDE > 0, the curve defines a scale factor for Young modulus evolution with equivalent plastic strain, which means the Young Modulus is scaled by the function :

The initial value of the scale factor should be equal to 1 and it decreases.

•	If fct_IDE = 0, the Young Modulus is calculated as:

Where, E and Einf are respectively the initial and asymptotic value of Young’s modulus, and is the accumulated equivalent plastic strain.

Note: If fct_IDE = 0 and CE = 0, Young modulus E is kept constant.