The failure due to accidental drop of magnetic recording disks made of brittle or ductile materials is of great interest in the design of small form factor hard disk drives. In this study, fracture of glass disks (brittle material) and plastic deformation of aluminum disks (ductile material) at very high shock levels caused by accidental drop are investigated using finite element analysis. It is found that failure inception for both disk types occurs at the inside perimeter of the disk. For glass disks, cracks are found to propagate toward the outer perimeter of the disk along distinct radial lines associated with the largest bending moment of the disk. The critical shock level at which failure originates increases with an increase in the clamp diameter, a reduction in the disk diameter, and an increase in the thickness of the disk. Some experimental results are presented to validate the numerical model.

1.
Schreck
,
E.
, 1994, “
Magnetic-Readback-Mapping and its Application to the Slider/Disc Interface Damage Due to Shock Impact
,”
STLE Proceedings on Tribology and Mechanics of Magnetic Storage Systems Symposia, IX
, pp.
5
10
.
2.
Allen
,
A. M.
, and
Bogy
,
D. B.
, 1996, “
Effects of Shock on the Head Disk Interface
,”
IEEE Trans. Magn.
0018-9464,
32
, pp.
3717
3719
.
3.
Edwards
,
J. R.
, 1999, “
Finite Element Analysis of the Shock Response and Head Slap Behavior of a Hard Disk Drive
,”
IEEE Trans. Magn.
0018-9464,
35
, pp.
863
867
.
4.
Lee
,
S. J.
,
Hong
,
S. K.
, and
Lee
,
J. M.
, 2001, “
A Study of Shock-Resistance Design of Suspension Subjected to Impulsive Excitation
,”
IEEE Trans. Magn.
0018-9464,
37
, pp.
826
830
.
5.
Lin
,
C. C.
, 2002, “
Finite Element Analysis of a Computer Hard Disk Drive Under Shock
,”
ASME J. Mech. Des.
0161-8458,
124
, pp.
121
125
.
6.
Zeng
,
Q. H.
, and
Bogy
,
D. B.
, 2002, “
Numerical Simulation of Shock Response of Disk-Suspension-Slider Air Bearing Systems in Hard Disk Drives
,”
Microsyst. Technol.
0946-7076,
8
, pp.
289
296
.
7.
Jayson
,
E. M.
,
Murthy
,
J.
,
Smith
,
P. W.
, and
Talke
,
F. E.
, 2002, “
Shock and Head Slap Simulations of Operational and Nonoperational Hard Disk Drives
,”
IEEE Trans. Magn.
0018-9464,
38
, pp.
2150
2152
.
8.
Murthy
,
A. N.
,
Feliss
,
B.
,
Gillis
,
D.
, and
Talke
,
F. E.
, 2006, “
Experimental and Numerical Investigation of Shock Response in 312 and 212 Inch Form Factor Hard Disk Drives
,”
Microsyst. Technol.
0946-7076,
12
, pp.
1109
1116
.
9.
Feliss
,
B.
,
Murthy
,
A. N.
, and
Talke
,
F. E.
, 2007, “
Microdrive Operational and Non-Operational Shock and Vibration Testing
,”
Microsyst. Technol.
0946-7076,
13
, pp.
1015
1021
.
10.
Bhargava
,
P.
, and
Bogy
,
D. B.
, 2007, “
Numerical Simulation of Operational-Shock in Small Form Factor Hard Disk Drives
,”
ASME J. Tribol.
0742-4787,
129
, pp.
153
160
.
11.
Bless
,
S. J.
,
Brar
,
N. S.
,
Kanel
,
G.
, and
Rosenberg
,
Z.
, 1992, “
Failure Waves in Glass
,”
J. Am. Ceram. Soc.
0002-7820,
75
, pp.
1002
1004
.
12.
Rosenberg
,
Z.
,
Bourne
,
N. K.
, and
Millett
,
J.
, 1996, “
Direct Measurements of Strain in Shock-Loaded Glass Specimens
,”
J. Appl. Phys.
0021-8979,
79
, pp.
3971
3974
.
13.
Bourne
,
N. K.
,
Millett
,
J.
,
Rosenberg
,
Z.
, and
Murray
,
N.
, 1998, “
On the Shock Induced Failure of Brittle Solids
,”
J. Mech. Phys. Solids
0022-5096,
46
, pp.
1887
1908
.
14.
Millett
,
J. C. F.
,
Bourne
,
N. K.
, and
Rosenberg
,
Z.
, 2000, “
Direct Measurements of Strain in a Shock-Loaded Lead Filled Glass
,”
J. Appl. Phys.
0021-8979,
87
, pp.
8457
8460
.
15.
Grady
,
D. E.
, 1998, “
Shock-Wave Compression of Brittle Solids
,”
Mech. Mater.
0167-6636,
29
, pp.
181
203
.
16.
Govindjee
,
S.
,
Kay
,
G. J.
, and
Simo
,
J. C.
, 1995, “
Anisotropic Modeling and Numerical Simulation of Brittle Damage in Concrete
,”
Int. J. Numer. Methods Eng.
0029-5981,
38
, pp.
3611
3633
.
17.
Elías
,
D. A.
, and
Chiang
,
L. E.
, 2003, “
Dynamic Analysis of Impact Tools by Using a Method Based on Stress Wave Propagation and Impulse-Momentum Principle
,”
ASME J. Mech. Des.
0161-8458,
125
, pp.
131
142
.
18.
Curran
,
D. R.
,
Seaman
,
L.
, and
Shockey
,
D. A.
, 1987, “
Dynamic Failure of Solids
,”
Phys. Rep.
0370-1573,
147
, pp.
253
388
.
19.
Seaman
,
L.
,
Curran
,
D. R.
, and
Shockey
,
D. A.
, 1976, “
Computational Models for Ductile and Brittle Fracture
,”
J. Appl. Phys.
0021-8979,
47
, pp.
4814
4826
.
20.
Costin
,
L. S.
,
Duffy
,
J.
, and
Freund
,
L. B.
, 1977, “
Fracture Initiation in Metals Under Stress Wave Loading Conditions
,” American Society of Testing and Measurement, Paper Nos. STP627-EB and STP27395S.
21.
Nakamura
,
T.
,
Shih
,
C. F.
, and
Freund
,
L. B.
, 1985, “
Elastic-Plastic Analysis of a Dynamically Loaded Circumferentially Notched Round Bar
,”
Eng. Fract. Mech.
0013-7944,
22
, pp.
437
452
.
22.
Nishioka
,
T.
, and
Atluri
,
S. N.
, 1983, “
Path-Independent Integrals, Energy Release Rates, and General Solutions of Near-Tip Fields in Mixed-Mode Dynamic Fracture Mechanics
,”
Eng. Fract. Mech.
0013-7944,
18
, pp.
1
22
.
23.
Rosakis
,
A. J.
, and
Ravichandran
,
G.
, 2000, “
Dynamic Failure Mechanics
,”
Int. J. Solids Struct.
0020-7683,
37
, pp.
331
348
.
24.
Voyiadjis
,
G. Z.
,
Palazotto
,
A. N.
, and
Gao
,
X. -L.
, 2002, “
Modeling of Metallic Materials at High Strain Rates With Continuum Damage Mechanics
,”
Appl. Mech. Rev.
0003-6900,
55
, pp.
481
493
.
25.
Ma
,
D.
, and
Lankarani
,
H. M.
, 1997, “
A Multibody/Finite Element Analysis Approach for Modeling of Crash Dynamic Responses
,”
ASME J. Mech. Des.
0161-8458,
119
, pp.
382
387
.
26.
Yang
,
R. J.
,
Wang
,
N.
,
Tho
,
C. H.
,
Bobineau
,
J. P.
, and
Wang
,
B. P.
, 2005, “
Metamodeling Development for Vehicle Frontal Impact Simulation
,”
ASME J. Mech. Des.
0161-8458,
127
, pp.
1014
1020
.
27.
Belytschko
,
T.
,
Liu
,
W. K.
, and
Moran
,
B.
, 2000,
Nonlinear Finite Elements for Continua and Structures
,
Wiley
,
New York
.
28.
2003,
DYNA Models for Crash Simulation of Automobiles
,
Insurance Institute for Highway Safety
.
29.
2004,
PRO/ENGINEER User Manual
,
Parametric Technology Corporation
,
Needham, MA
.
30.
2002,
HYPERMESH User Manual
,
Altair Computing Inc.
,
Troy, MI
.
31.
2003,
LS-DYNA User Manual
,
Livermore Software Technology Corporation
,
Livermore, CA
.
32.
Hallquist
,
J. O.
, 1998,
LS-DYNA Theoretical Manual
,
Livermore Software Technology Corporation
,
Livermore, CA
.
33.
Wong
,
E. H.
, 2005, “
Dynamics of Board-Level Drop Impact
,”
ASME J. Electron. Packag.
1043-7398,
127
, pp.
200
207
.
34.
Young
,
W. C.
, and
Budynas
,
R. G.
, 2002,
Roark's Formulas for Stress and Strain
,
7th ed.
,
McGraw-Hill
,
New York
.
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