Bolt-nut connectors play an important role in the safety and reliability of structural systems. Stress concentration due to unequal load distribution can cause fatigue failure in bolt-nut connectors. In this paper, the stress distribution in bolt-nut connectors is studied using an axisymmetric finite element model. Various geometric designs proposed in the literature were studied to determine the extent to which they reduce stress concentrations. Some well known modifications do significantly reduce the stress concentration factor (up to 85%) while other changes produce much more modest changes. The design modifications include things such as grooves and steps on the bolt and nut, and reducing the shank diameter of the bolt. All of the changes also result in a reduction in weight.

Issue Section:
Research Papers
Keywords:
fasteners, safety, reliability, fatigue, failure (mechanical), finite element analysis, design engineering
Topics:
Design, Stress, Stress concentration, Thread
1.
Bickford
,
J. H.
, and
Nassar
,
S.
, 1998,
Handbook of Bolts and Bolted Joints
,
Marcel Dekker
, New York, pp.
309
–
315
.
2.
Hetenyi
,
M.
, 1943, “
A Photoelastic Study of Bolt and Nut Fastenings
,”
Trans. ASME
0097-6822,
65
, pp.
A93
–
A100
.
3.
Seika
,
M.
,
Sasaki
,
S.
, and
Hosono
,
K.
, 1974, “
Measurement of Stress Concentrations in Threaded Connections
,”
Bull. JSME
0021-3764,
17
, pp.
1151
–
1156
.
Crossref
Search ADS
 
4.
Patterson
,
E. A.
, and
Kenny
,
B.
, 1987, “
Stress Analysis of Some Bolt-Nut Connections With Some Modifications to the External Shape of the Nut
,”
J. Strain Anal.
0022-4758,
22
, pp.
187
–
193
.
Crossref
Search ADS
 
5.
Patterson
,
E. A.
, and
Kenny
,
B.
, 1985, “
Stress Analysis of Some Bolt-Nut Connections With Modification to the Nut Thread Form
,”
J. Strain Anal.
0022-4758,
20
, pp.
35
–
40
.
6.
Kenny
,
B.
, and
Patterson
,
E. A.
, 1985, “
Load and Stress Distribution in Screw Threads
,”
Exp. Mech.
0014-4851,
25
, pp.
208
–
213
.
Crossref
Search ADS
 
7.
Fukuoka
,
T.
,
Yamasaki
,
N.
,
Kitagawa
,
H.
, and
Hamada
,
M.
, 1986, “
Stresses in Bolt and Nut
,”
Bull. JSME
0021-3764,
29
, pp.
3275
–
3279
.
Crossref
Search ADS
 
8.
Tanaka
,
M.
,
Miyazawa
,
H.
,
Asaba
,
E.
, and
Hongo
,
K.
, 1981, “
Application of the Finite Element Method to Bolt-Nut Joints
,”
Bull. JSME
0021-3764,
24
, pp.
1064
–
1071
.
Crossref
Search ADS
 
9.
Bretl
,
J. L.
, and
Cook
,
R. D.
, 1979, “
Modeling the Load Transfer in Threaded Connections by the Finite Element Method
,”
Int. J. Numer. Methods Eng.
0029-5981,
14
, pp.
1359
–
1377
.
Crossref
Search ADS
 
10.
Mackerle
,
J.
, 2003, “
Finite Element Analysis of Fastening and Joining: A Bibliography (1990–2002)
,”
Int. J. Pressure Vessels Piping
0308-0161,
80
, pp.
253
–
271
.
Crossref
Search ADS
 
11.
Zhao
,
H.
, 1998, “
Stress Concentration Factors Within Bolt-Nut Connectors Under Elasto-Plastic Deformation
,”
Int. J. Fatigue
0142-1123,
20
, pp.
651
–
659
.
Crossref
Search ADS
 
12.
Keniray
,
D. M.
, 1995, “
Effects of Stress Flow Guides on Overall Stress Concentration Factor in Plates, Shafts and Machine Threads
,” M.S. thesis, The Ohio State University, Columbus, OH.
13.
Kenny
,
B.
, and
Patterson
,
E. A.
, 1986, “
New Design of Nut Redistributes Axial Load
,” Des. Engng., pp.
30
–
36
.
14.
Marshek
,
K. M.
, 1987,
Design of Machine and Structural Parts
,
Wiley
, New York, pp.
166
–
168
.
15.
Juvinall
,
R. C.
, 1983,
Fundamentals of Machine Component Design
,
Wiley
, New York, pp.
291
–
292
.
16.
Brenner
,
H. S.
, 1980, “
Standard Fasteners
,”
Standard Handbook of Fastening and Joining
,
R. O.
Parmley
, ed.,
McGraw-Hill
, New York, pp.
1
–
2
.
17.
Pilkey
,
W. D.
, 1997,
Peterson’s Stress Concentration Factors
,
Wiley
, New York, pp.
387
–
388
.
18.
Staedel
,
W.
, 1933, “
Dauerfestigkeit von Schrauben
,”
Mitt. der Materialprufungsanstalt an der Technischen Hochschule Darmstadt, No. 4
,
VDI
, Berlin.
19.
Wiegand
,
H.
, 1933, “
Uber die Dauerfestigkeit von Schraubenwerkstoffen und Schraubenverbindungen
,” Thesis, Technische Hochschule Darmstadt, Dormstadt, Germany.
Copyright © 2006
 by American Society of Mechanical Engineers
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