FATIGUE LIVES OBTAINED IN RANDOM AND PROGRAM TESTS ON FULL-SCALE WING CENTER SECTIONS.
Abstract
Fatigue tests were conducted on eight full-scale wing center sections of the F-27 Friendship aircraft. The specimen consisted of the tension skin, including all stiffening elements. The remainder of the wing was replaced by a dummy structure. Two tests were carried out for each of the following load sequences: (1) random load (2) programmed load (3) random load with ground-to -air cycles (4) programmed load including ground-to-air cycles. The random loading was based on a simulation of strain gage records obtained by flying in turbulent air. The primary aim of the investigation was to study the equivalence of random and programmed loadings. A comparison of the fatigue lives and the critical components indicated the following trends: (a) Cracks were found in the same components for all tests. (b) The fatigue life under the programmed load was slightly longer than in the random load tests, both for tests without and with ground-to-air cycles. (c) The addition of ground-to-air cycles reduced the fatigue life to 50% or even less. For one fatigue-sensitive element sufficient data were available for a statistical evaluation; this indicated that the scatter within one structure may be smaller than the variability between a number of identical structures. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 15, 1963
- Accession Number
- AD0631574
Entities
People
- J. Schijve
- P. De Rijk