Development of Flight-by-Flight Fatigue Test Data from Statistical Distributions of Aircraft Stress Data. Volume I.

摘要

Axially loaded specimens of 7075-T651 aluminum with a hole were fatigue tested using loading histories derived from strain gage data recorded on operational aircraft. For the baseline data the magnitude and order in which the loads occurred during a flight were preserved. The flight contained data from taxi, takeoff, flight and landing strain histories. The data was processed by several counting techniques to obtain statistical distributions of the cyclic and mean stress amplitudes, as well as the number of stress cycles per flight for both the ground operations and the inflight operations. These distributions were then used to generate a series of flight-by-flight test sequences. Three different counting techniques were used to determine the statistical distribution of the cyclic stress for each of two aircraft types. The report presents the results in terms of the number of flights to failure for 9 sequences of B-58 data and 6 sequences for the F-106 data. A total of 91 specimens were tested. The report concludes that simulated testing sequences can yield the same fatigue life as the original strain gage data recorded on operational aircraft.