/MAT/LAW73

Block Format Keyword

/MAT/LAW73 - Thermal Hill Orthotropic Material

Description

This law describes the Thermal Hill orthotropic material and is applicable only to shell elements. This law differs from /MAT/LAW43 (HILL_TAB) by the fact that yield stress not only depends on strain rate and plastic strain, but also on temperature (it is defined by a user table).

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/MAT/LAW73/mat_ID/unit_ID
mat_title

E
fct_IDE		Einf		CE		Blank
r00		r45		r90		Chard		Iyield0

Tab_ID
Ti		Cp

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	Initial 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. 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 (Comment 3) 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
Iyield0	Yield stress flag (Integer) = 0: average yield stress input = 1: yield stress in orthotropic direction 1
	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 strain at which the stress in element is set to zero Default = 2.0 x 1030 (Real)
Tab_ID	Table identifier for yield stress definition (Integer)
	Yield stress scale factor Default set to 1.0 (Real)
	Strain rate scale factor Default set to 1.0 (Real)
Ti	Initial temperature Default set to 293 K (Real)
Cp	Specific heat per mass unit (Real)

(Steel)

#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:

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/MAT/LAW73/1/1

steel

# RHO_I

0.0078

# E NU

210000.0 0.3

# fct_IDE E_inf CE

0 0 0

# R00 R45 R90 C_hard I_yield0

1.6 1.6 1.6 0.0 0

# EPSP_MAX EPS_T1 EPS_T2

0 0 0

# table_ID SIGMA_SCALE EPSPT_SCALE

10 0 0

# TI CP

273. 4.

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

/TABLE/1/10

table

1011 0.0 273.

1013 0.02 300.

1013 0.04 300.

1012 0.0 300.

1012 0.02 273.

1012 0.04 273.

/FUNCT/1011

1st

0.0 185.0

0.1 339.0

1.0 339.0

/FUNCT/1012

2nd

0.0 190.0

0.1 344.0

1.0 344.0

/FUNCT/1013

3rd

0.0 195.0

0.1 349.0

1.0 349.0

#ENDDATA

/END

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

1.	This material law must be used with property set /PROP/TYPE9 (SH_ORTH) or /PROP/TYPE10 (SH_COMP).

2.	The yield stress is defined by a user function and the yield stress is compared to equivalent stress:

3.	Angles for Lankford parameters are defined with respect to orthotropic direction 1.

The Lankford parameters is the ratio of plastic strain in plane and plastic strain in thickness direction .

Where, is the angle to the orthotropic direction 1.

This Lankford parameters could be determined from a simple tensile test at an angle .

A higher value of R means better formability.

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

5.	If 1 (largest principal strain) , stress is reduced using the following relation:

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

7.	This law always uses iterative projection for plasticity (Iplas from the property set is ignored).

8.	This law is not available with global formulation for plasticity (N= 0 in the property shell is not available).

9.	The table for yield stress definition must be a 3-dimensional table whose parameters respectively represent plastic strain, strain rate, and temperature . Values of the table are yield stress values.

10.	If and and yield is linearly interpolated between the eight values of the table corresponding to , .

11.	If falls out of the range of the table, yield stress is obtained by linear extrapolation. Thus it is necessary to input into the table the static curves corresponding to zero strain rate (entry should belong to the table definition).

If the /HEAT/MAT option is not associated to the material identifier, adiabatic conditions are assumed and temperature is computed as:

where,

Eint is the internal energy computed by RADIOSS,

and Volume are the current density, and volume,

Cp is the heat capacity per mass unit.

Otherwise, the finite element formulation for heat transfer must be asked for (Iform = 1 in option /HEAT/MAT); initial temperature and specific heat input in the option /HEAT/MAT will then be used.

12.	If the yield stresses have been obtained in the orthotropic direction 1, define Iyield0 = 1; otherwise Iyield0 = 0.