SEDL / STP / STP714-EB / STP27490S

Effects of Fighter Attack Spectrum on Crack Growth

Dill, HD
Section chief-Technology and senior engineer-Technology, McDonnell Aircraft Co., St. Louis, Mo.

Saff, CR
Section chief-Technology and senior engineer-Technology, McDonnell Aircraft Co., St. Louis, Mo.

Potter, JM
Aerospace engineer, Air Force Flight Dynamics Laboratory, Wright-Patterson Air Force Base, Ohio

Pages: 13    Published: Jan 1980

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Abstract

The purpose of this program was to systematically evaluate the effect of variations in flight stress spectra on crack propagation using analysis in conjunction with experimental correlations. Over 100 spectrum variations were generated, derived from four baseline load factor spectra. Three constant amplitude and 30 spectrum tests were performed to verify predictions of the effects of spectrum variations and to provide data useful in defining guidelines for structural verification of future aircraft. Spectrum variations shown to have the greatest impact on crack growth life are those affecting the maximum peak stresses.