An experimental procedure is proposed for studying the underhead and thread friction in fasteners. The effective bearing friction radius, the underhead friction coefficient, and the thread friction coefficient are experimentally determined for fasteners with standard hexagonal heads and for flanged head fasteners. Hence, greater accuracy has been achieved in determining the value of the torque components that are consumed in overcoming friction in threaded fasteners. This would lead to a more reliable torque-tension correlation and would enhance the safety and quality of bolted assemblies. A design of experiment procedure is presented in order to investigate the effect of fastener material class, the thread pitch, and the fastener size on thread friction coefficient. For the underhead bearing friction, an experimental model is presented in order to determine the effect of the radii ratio of the contact area on the bearing friction radius.

Keywords:
Fastener Bearing Friction, Thread Friction, Fastener Torque Components, Fastener Torque-Tension, fasteners, machine bearings, friction, torque
Topics:
Bearings, Fasteners, Friction, Thread, Torque
1.
Bickford, J. H., 1997, An Introduction to the Design and Analysis of Bolted Joints, 3rd ed., Marcel Dekker, New York.
2.
Bickford, J. H., and Nassar, S., 1988, Handbook of Bolts and Bolted Joints, Marcel Dekker, New York.
3.
Juvinall, R. C., and Marshek, K. M., 2000, Fundamentals of Machine Component Design, 3rd ed., Wiley, New York.
4.
Jiang
,
Y.
,
Chang
,
J.
, and
Lee
,
C.
,
2000
, “
An Experimental Study of Torque-Tension Relationship for Bolted Joints
,”
Int. J. Mater. Prod. Technol.
,
16
(
4/5
),
417
–
429
.
5.
Motosh
,
N.
,
1976
, “
Development of Design Charts for Bolts Preloaded up to the Plastic Range
,”
ASME J. Eng. Ind.
,
98
, pp.
849
–
851
.
6.
Nassar
,
S.
,
Barber
,
G. C.
, and
Zuo
,
D.
,
2005
, “
Bearing Friction Torque in Bolted Joints
,”
STLE Tribol. Trans.
,
48
, pp.
1
–
7
.
7.
Nassar, S., Matin, P., and Barber, G. C., 2004, “Thread Friction Torque in Bolted Joints,” Proceedings of ASME Pressure Vessels and Piping Conference, July 25–29, San Diego, CA, pp. 145–154.
8.
Zou
,
Q.
,
Sun
,
T.
,
Nassar
,
S. A.
,
Barber
,
G. C.
,
El-Khiamy
,
H. M.
, and
Zhu
,
D.
,
2005
, “
Contact Mechanics Approach to Determine the Effective Bearing Radius in Bolted Joints
,”
ASME J. Tribol.
,
127
, pp.
1
–
7
.
Copyright © 2005
 by ASME
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