Random vibration. Wiley, New York. Whereas sinusoidal vibration occurs at distinct frequencies, random vibration contains all frequencies simultaneously. 3. It’s intensity is defined using a Power Spectral Density (PSD) spectrum. Random vibration is also more realistic than sinusoidal vibration testing because random simultaneously includes all the forcing frequencies and “simultaneously excites all our product’s resonances.” ¹ Under a sinusoidal test, a particular resonance frequency might be found for one part of the device under test and at a different frequency, another part of the DUT may resonate. Sine and random vibration testing cannot be equated. Also phase changes occur over time with random vibration. Chung YT, Krebs DJ, Peebles JH (2001) Estimation of payload random vibration loads for proper structure design. Wijker JJ (2008) Spacecraft structures. (2.29) is not mathematically valid in the case of non-uniform flow because the power spectral density (PSD) of the excitation force, S F ω)(=2G(ω)) depends on the axial location along the tube. Random Vibration is a varying waveform. It does not refer to the physical quantity power such as watts or horsepower. These pages were created to assist you when doing random vibration analysis. ISBN 0-471-58579-3 Google Scholar. Consider Tustin’s description of random vibration: “I’ve heard people describe a continuous spectrum (random vibration, VRC), say 10-2000 Hz as ‘1990 sine waves 1 Hz apart.’ No. To avoid this problem, the following two approximate methods are applied: 1. Random vibration consists of all the frequencies in a defined spectrum that are sent to the shaker at any given time. 2. Power refers to the fact that the magnitude of the PSD is the mean-square value of the signal being analyzed. Eq. Random Vibration Analysis. ISBN 978-3-540-755524 Google Scholar. 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