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Natural Frequencies and Mode Shapes of Plates with Interior Cut-Outs. x
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING
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The effect of square holes on the natural frequencies and mode shapes of a 7 in. x 10 in. clamped rectangular plate were investigated. The frequencies of the first five modes were obtained in separate experiments using holographic interferometry and accelerometers and analytically using the finite element method. The shapes were observed in the holography experiment and photographs were taken. For a plate without holes, the experimental frequencies were approximately 10 lower than the theoretical values possible due to some rotation of the plate edges. Using a 25 element model, the finite element program gave frequencies within 1 of the theoretical values. For central square holes, the frequencies of each mode varied with hole size in a number of ways. A correlation between the variation of frequencies and mode shapes was noted. Modified author abstract
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