/MAT/LAW66

Block Format Keyword

/MAT/LAW66 - Visco-Elastic Plastic Piecewise Linear Material

Description

This law models an isotropic tension-compression elasto-plastic material law using user-defined functions for the work-hardening portion of the stress-strain (plastic strain vs. stress).

This law can be defined for compression and tension.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/MAT/LAW66/mat_ID/unit_ID
mat_title

E				Chard		Fcut		Fsmooth	Iyld_rate
Pc		Pt

Read only if Iyld_rate = 0, 1 or 2

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
fct_IDc	fct_IDt	Fscalec		Fscalet
		c				VP

Read only if Iyld_rate = 3

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
fct_IDc	fct_IDt	Fscalec		Fscalet
Frate_IDc	Frate_IDt	Fscale_ratec		Fscale_ratet

Read only if Iyld_rate = 4

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
NFUNCC	NFUNCT

For each NFUNCC

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
fct_IDc				Fscalec

For each NFUNCT

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
fct_IDt				Fscalet

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)
Chard	Hardening coefficient (Real) = 0: the hardening is a full isotropic model = 1: the hardening uses the kinematic Prager-Ziegler model = value between 0 and 1: the hardening is interpolated between the two models
Fsmooth	Smooth strain rate option flag Default = 0 (Integer) = 0: no strain rate smoothing = 1: strain rate smoothing active
Fcut	Cutoff frequency for strain rate filtering Default = 1030 (Real)
Iyld_rate	Rate effect on the yield stress flag Default = 1 (Integer) = 1: Using Cowper-Symonds: = 2: By using: = 3: By using two load curves to scale the yield stress (fct_IDc) in compression and tension (fct_IDt). = 4: By using different functions for compression and tension for different strain rate values.
Pc	Limit pressure in compression Default = 0 (Real)
Pt	Limit pressure in tensile Default = 0 (Real)
fct_IDc	Compression yield stress (Integer)
fct_IDt	Tension yield stress (Integer)
Fscalec	Scale factor for ordinate (stress) in fct_IDc Default = 1.0 (Real)
Fscalet	Scale factor for ordinate (stress) in fct_IDt Default = 1.0 (Real)
c	Strain rate parameter (Real)
	Reference strain rate Default = 1.0 (Real)
	Initial yield stress Default = 0 (Real)
VP	Strain rate choice flag (Integer) = 0: strain rate effect on the yield stress is depending on the total strain rate = 1: strain rate effect on the yield stress is depending on plastic strain rate Only available if Iyld_rate = 1 (Cowper Symonds) - (Comments 2 and 3)
Frate_IDc	Compression strain rate effect function identifier (Integer)
Frate_IDt	Tension strain rate effect function identifier (Integer)
Fscale_ratec	Scale factor for ordinate (stress) in Frate_IDc Default = 1.0 (Real)
Fscale_ratet	Scale factor for ordinate (stress) in Frate_IDt Default = 1.0 (Real)
NFUNCC	Number of compression function (Integer)
NFUNCT	Number of tension function (Integer)
	ith compression strain rate i =1,NFUNCC (Real)
	ith tension strain rate i =1,NFUNCT (Real)

#RADIOSS STARTER

/UNIT/1

unit for mat

g mm ms

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#- 2. MATERIALS:

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/MAT/LAW66/1/1

Aluminum

# RHO_I

.0027

# E NU C_hard F_cut F_smooth Iyld_rate

60400 .33 0 0 0 4

# P_c P_t

500 600

# NFUNCC NFUNCT

2 2

# fct_IDc Episilon_c Fscalec

38 10 1

40 40 1.6

# fct_IDt Episilon_t Fscalet

38 10 1

40 40 1.6

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#- 3. FUNCTIONS:

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/FUNCT/38

function_38

# X Y

0 90

.08 170

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

/FUNCT/40

function_40

# X Y

0 90

.08 170

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

#ENDDATA

/END

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This is an isotropic elastic-plastic law. The yield stress is defined by using the compression and tension yield stress versus effective plastic strain for the both (compression and tension). When exceeded, the two pressures Pt and Pc, determine if the tension yield stress or compression yield stress is used respectively.

If the pressure is between these two values, the yield stress is given by:

If –Pt < P < Pc,