Study of Statistical Variations of Load Spectra and Material Properties on Aircraft Fatigue Life
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 o spectrum may be too severe. This conclusion is only valid for a three o spectrum based on the A-6 load history.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1992
- Accession Number
- ADA257961
Entities
People
- Richard W. Walter Ii
Organizations
- Naval Postgraduate School