Accession Number : AD0631575

Title :   CRACK PROPAGATION AND RESIDUAL STRENGTH OF FULL SCALE WING CENTER SECTIONS.

Descriptive Note : Scientific rept.,

Corporate Author : NATIONAL AERO- AND ASTRONAUTICAL RESEARCH INST AMSTERDAM (NETHERLANDS)

Personal Author(s) : Broek,D.

Report Date : 1964

Pagination or Media Count : 62

Abstract : Fatigue tests were conducted on eight full-scale wing center sections of the Fokker F.27 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 sequencies: (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 crack propagation data indicated the following trends: (a) crack propagation was slightly higher under a randomly varying load than under a programmed load sequence, (6) addition of the ground-to-air cycles increased crack propagation rates by an amount of about 50%. As for the residual static strength of the structure in the presence of cracks the following remarks can be made: (a) if cracks are short the structure behaves like an unstiffened panel, (b) for long cracks the stringers become effective in raising the residual strength. (Author)

Descriptors :   (*WINGS, LOADS(FORCES)), (*FATIGUE(MECHANICS), WINGS), (*FAILURE(MECHANICS), WINGS), TENSILE PROPERTIES, PROPAGATION, TESTS, SIMULATION, NETHERLANDS, TRANSPORT AIRCRAFT

Subject Categories : Transport Aircraft
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE