Study of statistical variations of load spectra and material properties on aircraft fatigue life
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Authors
Walter, Richard W.
Subjects
Advisors
Lindsey, Gerald H.
Date of Issue
1992-09
Date
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
NAVAIR utilizes the fatigue spectrum of an existing Navy aircraft
to set the structural design requirements for a new Navy aircraft.
The current design requirement is for the new aircraft to withstand a
fatigue spectrum at least as severe as the spectrum experienced by
99.73% (3 standard deviations) of the aircraft from which the design
requirement originated. Two years of A-6 data were used in the
study, which contained the number of g exceedences at the four g,
five g, six g, and seven g levels. Trade off studies were completed to analytically examine the
variation in the fatigue life of an aircraft while varying the reference
stress at the notch of a crack, re-ordering of the load sequences
within the spectrum, varying the 3 sigma design requirement, and
changing the material properties of the metal.
The results indicated that NAVAIR's current requirement for a
new aircraft to withstand a three a spectrum may be too severe.
This conclusion is only valid for a three a spectrum based on the A-6
load history.
Type
Thesis
Description
Series/Report No
Department
Aeronautical Engineering
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
Sponsors
Funder
Format
77 p.;28 cm.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.