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APPLICATIONS OF THE PROXIMITY SPECTRUM INCLUDING SPECTRA OF SOME SIMPLE SHOCK DESIGN AND TEST MOTIONS.
AIR FORCE FLIGHT DYNAMICS LAB WRIGHT-PATTERSON AFB OH
The concept of a proximity criterion was developed in a paper presented at the 34th Shock and Vibration Symposium. It was suggested that this concept could be expanded to a proximity spectrum which would provide useful insights into the effects of shock motions not obtainable from either the Fourier Spectrum or the shock spectrum. The proximity criterion indicates the effects of shock on a simple idealized equipment consisting of two uncoupled linear single-degree-of-freedom systems mounted to a common rigid base. When the base undergoes a shock motion, the distance between the two masses varies. The change in the distance between these two systems is called the proximity criterion. In some types of failure e.g. electrical malfunctions and collision of parts this criterion is important. This paper develops the proximity criterion into the proximity spectrum by varying the natural frequencies of the two systems so that data can be obtained for spectral plots. Digital computation is employed for obtaining data from a mathematical model. The technique provides means of comparing different shock motions in terms of their effects on a standard equipment. Proximity spectra of the half-sine, terminal peak sawtooth, and rectangular shock motions are presented. Author
Technical rept. Jan-Sep 65,