/FAIL/SNCONNECT

Block Format Keyword

/FAIL/SNCONNECT - Failure According Plastic Strain Criteria

Description

Describes the failure model for CONNECTION material with plastic stain criteria. This model allows a different failure behavior in normal and shear directions.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/FAIL/SNCONNECT/mat_ID/unit_ID
								Ifail_so	ISYM
fct_IDON	fct_ID0S	fct_IDFN	fct_IDFS	XSCALE_0		XSCALE_F		AREAscale

Optional line:

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

Field	Contents	SI Unit Example
mat_ID	Material identifier (Integer, maximum 10 digits)
unit_ID	Optional unit identifier (Integer, maximum 10 digits)
	Parameter for initial yield function referring to the beginning of damage. (Real)
	Exponent for initial yield function referring to the beginning of damage. (Real)
	Parameter for final yield function referring to rupture (Real)
	Exponent for final yield function referring to rupture (Real)
Ifail_so	Solid failure flag Default = 1 (Integer) = 1: the solid element is deleted, when one integration point reaches the failure criteria = 2: the solid element is deleted, when all integration points reach the failure criteria
ISYM	Rupture deactivation flag for compression Default = 0 (Integer) = 0: Same behavior in tension and compression = 1: Deactivation of failure in case of compression
fct_IDON	Function identifier defining a scale factor for strain rate dependency in normal direction in initial yield function. Default = 0 (Integer)
fct_ID0S	Function identifier defining a scale factor for strain rate dependency in tangential direction in initial yield function. Default = 0 (Integer)
fct_IDFN	Function identifier defining a scale factor for strain rate dependency in normal direction in rupture yield function. Default = 0 (Integer)
fct_IDFS	Function identifier defining a scale factor for strain rate dependency in tangential direction in rupture yield function. Default = 0 (Integer)
XSCALE_0	Scale factor for the abscissa strain rate for initial function Default = 1.0 (Real)
XSCALE_F	Scale factor for the abscissa strain rate for rupture function Default = 1.0 (Real)
AREAscale	Failure scale factor for area increase (Comment 5) Default = 0.0 (Real)
fail_ID	(Optional) Failure criteria identifier (Comment 3) (Integer, maximum 10 digits)

#RADIOSS STARTER

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

/UNIT/1

unit for mat

kg 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/LAW83/1/1

CONNECT MATERIAL

# RHO_I

7.8E-6

# E Imass

20 0

# fct_ID1 Y_scale1 X_scale1 ALPHA BETA

200 1 1 0 2

# RN RS Fsmooth Fcut

.2 .4 0 0

# fct_IDN fct_IDS XSCALE

0 0 0

/FAIL/SNCONNECT/1/1

# ALPHA_0 BETA_0 ALPHA_F BETA_F Ifail_so ISYM

0 2 0 2 1 1

# fct_0N fct_0S fct_FN fct_FS XSCALE_0 XSCALE_F

2001 2002 2003 2004 1 1

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

#- 3. FUNCTIONS:

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

/FUNCT/200

MAT83 curve

# X Y

0 1

1 1

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

/FUNCT/2001

fct_0N

# X Y

0 .5

1 .5

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

/FUNCT/2002

fct_0S

# X Y

0 .5

1 .5

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

/FUNCT/2003

fct_FN

# X Y

0 1

1 1

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

/FUNCT/2004

fct_FS

# X Y

0 1

1 1

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

#ENDDATA

/END

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

1.	This failure model is compatible only with the connection materials, /MAT/CONNECT and /MAT/LAW83.

2.	A combined energy failure criteria is defined such as:

fail_snconnect

With being the elongation.

Damage of element begins when the first surface is reached which is described by the following equation:

The damage factor is computed as:

and the stress is reduced as .

The element is deleted when the rupture surface is reached:

•	Parameters in bold are the input variables.

•	sym is the sign of the angle between the normal of the lower surface and the normal of the upper surface of the solid element.

3.	The fail_ID is used with /STATE/BRICK/FAIL and /INIBRI/FAIL. There is no default value. If the line is blank, no value will be output for failure model variables in the /INIBRI/FAIL (written in .sta file with /STATE/BRICK/FAIL option).

4.	With /ANIM/BRICK/VDAMA following damage variable value could be output in an animation file:

VDMA1 = d is the damage value

VDAM2 = is the damage surface

VDAM3 = is the rupture surface

The area is calculated as the mean value of the upper and lower surface of the solid element. If the actual area reaches the value of initial area multiplied by the AREAscale factor, the whole element will be deleted. The default value is set to zero. This causes no deletion, due to area increase. The application is to prevent shooting nodes, if the cohesive element nodes will be released, when surrounding elements start to fail and erode.