This paper presents the results from dynamic tests that investigate the effect of thread dimensional conformance of fasteners on vibration-induced loosening. Test specimens include combinations of bolts and nuts within dimensional conformance as specified by ASME Standard B1. 1-1992, as well as bolts with undersized pitch and major diameters and nuts with oversized pitch and minor diameters. Tests were performed using an inertial loaded compound cantilever beam apparatus that subjects the test fasteners to a vibration environment. Data from the tests show a significantly degraded resistance to vibration for the fastener combinations with undersized pitch and major bolt diameters or oversized pitch and minor nut diameters, compared to fastener combinations within conformance. Specifically, the lower 90 percent confidence limit for the time to failure for conforming specimens was 782 seconds compared to 8 to 29 seconds for nonconforming specimens.

Issue Section:
Research Papers
Topics:
Thread, Vibration, Fasteners, ASME Standards, Cantilever beams, Dynamic testing (Engineering), Failure
1.
ASME B 1.1-1992, 1992, Unified Inch Screw Threads, An American National Standard, The American Society of Mechanical Engineers, New York.
2.
Haviland, G. S., 1980, A Logical Approach to Secure Bolting and Locking, Loctite Corporation, Newington, Connecticut.
3.
Haviland
G. S.
,
1983
, “
Designing with Threaded Fasteners
,”
Mechanical Engineering
, Vol.
105
, pp.
17
–
31
.
4.
Hess
D. P.
,
1997
, “
Dimensional Conformance and Mechanical Performance of Threaded Components
,”
Fastener Technology International
, Vol.
XX
, pp.
75
–
77
.
5.
Hess, D. P., 1998, “Vibration and Shock Induced Loosening,” Chapter 40 in Handbook of Bolts and Bolted Joints, J. H. Bickford and S. Nassar, eds., Marcel Dekker, New York, pp. 757–824.
6.
Hess, D. P., and Dong, Y., 1998, “Tests Investigating the Effect of Thread Dimensional Conformance on Vibration-induced Loosening,” Research Report, Mechanical Engineering Department, University of South Florida, Tampa, Florida.
7.
Kerley, J. J., 1982, The Use and Misuse of Six Billion Bolts Per Year, NASA, Goddard Space Flight Center, Engineering Services Division, Maryland (Presented at the 35th Meeting of Mechanical Failures Prevention Group, National Bureau of Standards).
8.
Kerley, J. J., 1987, An Application of Retroduction to Analyzing and Testing the Backing Off of Nuts and Bolts During Dynamic Loading, NASA Technical Memorandum 4001, Goddard Space Flight Center, Maryland.
9.
MIL-STD-1312-7A, 1984, Fastener Test Methods—Method 7: Vibration, United States Department of Defense Military Standard, Washington, DC.
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