平均应力对非高斯随机振动疲劳损伤的影响研究OA

Fatigue failure represents one of the primary failure modes in engineering structures.Although the frequency domain method can quickly estimate the fatigue damage rate,it struggles to effectively consider the influence of the mean of each stress cycle when dealing with non-Gaussian random loads.Therefore,systematically investigating the influence of mean stress on fatigue damage under non-Gaussian random vibrations is crucial.Firstly,a Gaussian random process is generated using the trigonometric series method,and non-Gaussian characteristics are introduced through a nonlinear transformation model.Secondly,the power spectral shape,bandwidth,skewness,kurtosis,global mean stress and the mean of each stress cycle are comprehensively considered.Finally,numerical simulations are conducted to investigate the influence of mean stress on non-Gaussian fatigue damage calculations under various conditions.The results show that the frequency domain method considering the global mean stress can effectively estimate fatigue damage under Gaussian and zero-skewness non-Gaussian loads.However,when subjected to non-Gaussian loads with significant skewness,the mean distribution of stress cycles is influenced by the coupled effects of skewness and kurtosis.At this point,it is necessary to use the time-domain method to consider the mean of each stress cycle.