PRACTICAL AND THEORETICAL BASES FOR SPECIFYING A TRANSPORTATION VIBRATION TEST
REED RESEARCH INC WASHINGTON DC
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Each services material probably will be carried by rail, truck, ship or airplane from factory to the ultimate consumer. Despite similarity of total vibration environment, at least seven different vibration tests are prescribed. Emphasis is on developing a theoretical basis for a laboratory test since theory will define the numerical values of the shipping environment which should be collected. A modern statistical theory theory of random vibration is indicated. Equations show content mean square response in terms of suspension natural frequency and damping ratio and the environmental characteristics of acceleration spectral density and bandwidths. Linear fatigue accumulation concepts are used as a basis for realistically shortening test times. Two expressions equate sinusoidal test response amplitude and time with field time and the field response amplitude previously derived. The equations show that it is sufficient, when evaluating the suspension, to vibrate at a single frequency, preferably the lowest resonant.