/MAT/LAW87 (BARLAT2000) (New!)

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/MAT/LAW87 - Barlat YLD2000

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This elasto-plastic law is developed for anisotropic materials especially aluminum alloys. Yield stresses can be defined either by user-defined functions (plastic strain vs. stress) or analytically by a combination of Swift-Voce model. The model is based on Barlat YLD2000 criterion (Barlat [2003]).

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/MAT/LAW87/mat_ID/unit_ID or MAT/BARLAT2000/mat_ID/unit_ID
mat_title

E				Iflag


Blank Line
a				n		Fcut		Fsmooth	Nrate
Aswift				Qvoce				k0
fct_IDi		Yscalei

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- 8 (Real)
Iflag	Yield stress definition flag Default = 0 (Integer) = 0: Tabulated input = 1: Swift-Voce analytic formulation
	Material parameters with i=1~8. See equation below. (Real)
a	Exponent in yield function. See equation below. (Real)
fct_IDi	Yield stress vs plastic strain identifier (Integer)
Yscalei	Scale factor for ordinate for fct_IDi Default = 1.0 (Real)
	Yield weighting coefficient Default = 0.0 (Real)
Qvoce	Voce hardening coefficient (Real)
k0	Voce hardening parameter (Real)
	Voce plastic strain coefficient Default = 0.0 (Real)
Aswift	Swift hardening coefficient (Real)
n	Swift hardening exponent Default = 1.0 (Real)
	Swift hardening parameter Default = 0.00 (Real)
Fsmooth	Smooth strain rate option flag (Comment 3) Default = 0 (Integer) = 0: no strain rate smoothing = 1: strain rate smoothing active
Fcut	Cutoff frequency for strain rate filtering Default = 1030 (Real)
Nrate	Number of yield functions (Comment 2) (Integer)
	Strain rate i corresponding to fct_IDi Default = 1 (Real)

1.	The yield function is expressed as:

X' and X" denote the principal values of the tensors X' and X'' which are a linear transformation of the stress deviator, which leads to:

The tensors X' and X'' are linear transformations of the stress tensor:

2.	The yield stress could be defined either by tabulated input or using the analytic Swift-Voce model.

•	If tabulated, it is possible to add total strain rate dependency by defining a number Nrate of functions

•	The analytic Swift Voce model is expressed as:

With is the equivalent plastic strain.

3.	The strain rate filtering is available to smooth strain rates when tabulated input is chosen.

List of Animation output (in /ANIM/SHEL/USRII/JJ):

USR 1= plastic strain

USR 2= effective stress

USR 3= increment of plastic strain

Barlat et al. [2003] Barlat F., Brem J.C., Yoon J.W, Chung K., Dick R.E., Lege D.J., Pourboghrat F., Choi, E. Chu S.-II, (2003), Plane stress yield function for aluminum alloy sheets—part 1: Theory, International Journal of Plasticity, Volume 19, Issue 8, August, Pages 1215-1244.

/MAT/LAW87 (BARLAT2000)

/MAT/LAW87 (BARLAT2000)

/MAT/LAW87 (BARLAT2000)

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