/FAIL/HASHIN

Block Format Keyword

/FAIL/HASHIN - Hashin Composite Failure Model

Description

Describes the Hashin failure model.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/FAIL/HASHIN/mat_ID/unit_ID
Iform	Ifail_sh	Ifail_so	ratio


		Sdel

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)
Iform	Formulation flag Default = 1 (Integer) = 1: uni-directional lamina model = 2: Fabric lamina model
Ifail_sh	Shell failure flag Default = 1 (Integer) = 1: Shell is deleted, if damage is reached for one layer. = 2: Shell is deleted, if failed layer > all layer * RATIO = 3: Shell is deleted, if all layers (except 1) have failed
Ifail_so	Solid failure flag Default = 1 (Integer) = 1: Solid is deleted, if damage is reached for one integration point of solid. = 2: Solid is deleted, if failed int_point > all int_point * RATIO = 3: Solid is deleted, if all integration points (except 1) have failed
ratio	Default= 1.0 (Real) For Isolid=2 or Ifail_sh=2: the element will be deleted, if more than ratio of the layers (or integration points) have failed
	Longitudinal tensile strength Default = 1030 (Real)
	Transverse tensile strength Default = 1030 (Real)
	Through thickness tensile strength Default = 1030 (Real)
	Longitudinal compressive strength Default = 1030 (Real)
	Transverse compressive strength Default = 1030 (Real)
	Crush strength Default = 1030 (Real)
	Fiber shear strength Default = 1030 (Real)
	Matrix shear strength 12 Default = 1030 (Real)
	Matrix shear strength 23 Default = 1030 (Real)
	Matrix shear strength 13 Default = 1030 (Real)
	Coulomb friction Angle for matrix and delamination < 90 degrees Default = 0 (Real)
Sdel	Delamination criteria scale factor Default = 1.0 (Real)
	Dynamic time relaxation (Comment 6) Default = 1030 (Real)
fail_ID	(Optional) Failure criteria identifier (Comment 5) (Integer, maximum 10 digits)

With tension and compression tests (see below) of single composite layer and pure matrix test to determine the strength and yield stress, which are used in material LAW25 and in failure model HASHIN. Delamination is not considered in this example.

fail_hashin_example

Fabric lamina model (Iform =2) is used

#RADIOSS STARTER

/UNIT/1

unit for mat and failure

# MUNIT LUNIT TUNIT

kg mm ms

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

/MAT/COMPSH/1/1

composite material

# RHO_I

1.5E-6

# E11 E22 NU12 Iform E33

42 40 .05 1 .5

# G12 G23 G31 EPS_f1 EPS_f2

3.4 3 3 0 0

# EPS_t1 EPS_m1 EPS_t2 EPS_m2 dmax

0 0 0 0 .9999

# Wpmax Wpref Ioff IFLAWP ratio

0 0 5 0 0

# c EPS_rate_0 alpha ICC_global

0 2E-4 0 1

# sig_1yt b_1t n_1t sig_1maxt c_1t

.1 25 .1 0 0

# EPS_1t1 EPS_2t1 SIGMA_rst1 Wpmax_t1

0 0 0 0

# sig_2yt b_2t n_2t sig_2maxt c_2t

.1 20 .1 0 0

# EPS_1t2 EPS_2t2 sig_rst2 Wpmax_t2

0 0 0 0

# sig_1yc b_1c n_1c sig_1maxc c_1c

.005 800 .5 0 0

# EPS_1c1 EPS_2c1 sig_rsc1 Wpmax_c1

.08 .15 .1 0

# sig_2yc b_2c n_2c sig_2maxc c_2c

.005 2000 .5 0 0

# EPS_1c2 EPS_2c2 sig_rsc2 Wpmax_c2

0 0 0 0

# sig_12yt b_12t n_12t sig_12maxt c_12t

.004 83 .31 0 0

# EPS_1t12 EPS_2t12 sig_rst12 Wpmax_t12

.075 .085 .05 0

# GAMMA_ini GAMMA_max d3max

1E31 1E31 .9999

# Fsmooth Fcut

0 0

/FAIL/HASHIN/1/1

# Iform Ifail_sh Ifail_so Ratio

2 1 0 0

# Sigma1_T Sigma2_T Sigma3_T Sigma1_C Sigma2_C

2 .525 1E30 1.7 1.7

# Sigma_C SigmaF_12 SigmaM_12 SigmaM_23 SigmaM_13

1E30 1E30 .075 1E30 1E30

# Phi Sdelam Tau_max

0 1 .01

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

#enddata

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

1.	This failure model is available for Shell and Solid.

2.	Example of “ratio”: if ratio = 0.5, and Ifail_sh =2 (or Ifail_so =2), the element will be deleted, if more than half of the layers (or integration points) failed.

3.	The 3D material failure model:

•	Uni-directional lamina model:

Tensile/shear fiber mode:

Compression fiber mode:

Crush mode:

Failure matrix mode:

Delamination mode:

where:

Note:

•	Fabric lamina model:

Tensile/shear fiber mode:

With:

Compression fiber mode:

Crush mode:

Shear failure matrix mode:

Matrix failure mode:

where:

If the damage parameter is Fi > 1.0, the stresses are decreased by using an exponential function to avoid numerical instabilities. A relaxation technique is used by decreasing the stress gradually:

With,

where,

t is the time

tr is the start time of relaxation when the damage criteria is assumed

is the time of dynamic relaxation

is the stress components at the beginning of damage

4.	The damage value, D is 0 < D < 1. The status for fracture is:

•	Free, if 0 < D < 1

•	Failure, if D =1

with D = Max( F1 , F2 , F3 , F4). This damage value shows with /ANIM/BRICK/DAMA or /ANIM/SHELL/DAMA.

5.	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).

The value of

determines a period of time after failure criterion is reached when the stress in failed element is gradually reduced to zero, then the element is deleted. This is necessary to avoid instability coming from a sudden element deletion and failure "chain reaction" in the neighboring elements. The default value of

is set to 1e30. With this value, elements will not be deleted, even if the failure criterion is reached. Normal value of

is 10 times higher than the actual time step should be set in the card directly.

Hashin, Z., and Rotem, A., "A Fatigue Criterion for Fiber-Reinforced Materials," Journal of Composite Materials, Vol. 7, 1973, pp. 448-464. 9)

Hashin, Z., "Failure Criteria for Unidirectional Fiber Composites," Journal of Applied Mechanics, Vol. 47, 1980, pp. 329-334.