A method for simulating the random acoustic excitation on a stiffened panel with an electromagnetic shaker was developed. The shaker simulation of the acoustic loading was verified both experimentally and theoretically over a wide range of axially applied tension and compression loads. Two flight-by-flight load spectra, corresponding to the upper and lower wing surface loads for typcal Advanced Medium Transport Aircraft were developed and used in the test program. Real time takeoff and accelerated flight durations were used. The shaker simulated acoustic and axial flight-by-flight loads were applied both separately and simultaneously to a total of twelve stiffened panels. The measured crack growth data was compared with current analysis methods. Crack propagation paths, and magnified photographs and fractographs of the crack surfaces are presented. No significant effects on the crack growth rate are obtained by the simultaneous application of the acoustic and flight loads. The observed crack branching is, however, attributed to the acoustic loading.
Effects of combined acoustic and flight loads of crack growth
Wirkung der kombinierten Schall- und Fluglasten auf die Rissbildung und Rissausbreitung
US Government Reports ; 1-161
1976
161 Seiten
Report
Englisch
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