新型高峰度系数随机振动测试信号生成方法

justifying Random vibration testing is significant for automotive and aerospace components testing. The vibration signal is usually generated by applying inverse fast fourier transform (IFFT) to the desired power spectral density (PSD) combined with a randomly generated phase spectrum. However, this method leads to a Gaussian-distributed signal with a Kurtosis 3, which differs a lot from the realistic vibration signal which typically contains distinctive peaks above average level of vibration and has a higher kurtosis. In this paper, a new method is proposed to increase effectively the kurtosis of testing signal without affecting the signal PSD. This method relies on the design of phase spectrum by taking part of it from a template time-domain signal and randomizing the rest of it. Two important parameters in the frame of this method are studied, which are demonstrated by simulation and experiments to have a clear and significant influence on the signal kurtosis. This method can cooperate with the existing vibration testing method and a potential control strategy can be designed by using these two parameters proposed to control the signal kurtosis, improve the testing performance.