Comparison of the Sonic Fatigue Characteristics of Four Structural Designs
Final rept. Jan 1972-Dec 1975
AIR FORCE FLIGHT DYNAMICS LAB WRIGHT-PATTERSON AFB OH
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An experimental program was conducted under which the response and sonic fatigue resistance of four lightweight 1 lbsq ft aircraft structural panel types were investigated. Specifically, six sets of 20 aluminum alloy 7075-T 6 panels were tested one design of skin-stringer, three designs of bonded-beaded, one design of chem-milled, and one design of corrugated panels. Each set of 20 panels was tested in four groups of five panels to obtain results with high statistical confidence levels. The data gathered included panel damping ratios, rms stress, fatigue life and failure types. For some panel types, fatigue data in excess of ten to the eight power cycles were obtained. A comparison of the sonic fatigue resistance of the four structural designs was made and sonic fatigue design charts for bonded beaded panels developed.
- Metallurgy and Metallography