Accession Number : ADA257961


Title :   Study of Statistical Variations of Load Spectra and Material Properties on Aircraft Fatigue Life


Descriptive Note : Master's thesis


Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA


Personal Author(s) : Walter II, Richard W


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a257961.pdf


Report Date : Sep 1992


Pagination or Media Count : 83


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.


Descriptors :   *AIRCRAFT , *FATIGUE LIFE , *LOADS(FORCES) , *VARIATIONS , *SPECTRA , *STATISTICAL ANALYSIS , *MATERIALS , REQUIREMENTS , HISTORY , FATIGUE , STRUCTURAL COMPONENTS , NUMBERS , STANDARDS , THESES , SEQUENCES , CRACKS , NAVY , METALS , COMMERCE


Subject Categories : Aircraft
      Logistics, Military Facilities and Supplies
      Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE