On the Use of Kurtosis Control Methods in Shaker Testing for Fatigue Damage

摘要

Random vibration testing with increased kurtosis introduces high peaks into shaker drive signalsto simulate land vehicle vibration more accurately and also to shorten the required test time.Two methods of controlling kurtosis by phase manipulation in the inverse fast Fourier transformwere implemented, tested, and compared. The first method generates high-kurtosis excitationswith a gradual, smooth pattern of peak heights from low to high, and the second method producesisolated high peaks with intervals of stable background vibration between them. Whenapplying a kurtosis increase for accelerated fatigue damage testing, the kurtosis control methodmust be able to pass high-kurtosis values from the generated shaker table vibration into thestress response of the unit under test. However, this is not always the case, and only one ofthe considered methods was capable of doing so. In the article, the fatigue damage spectrummodel was used for an evaluation of the time to failure. An experimental study was carried outusing operational vibration measured in a car. Shaker testing of cantilever specimens was performedfor Gaussian, non-Gaussian, and accelerated non-Gaussian excitations.