Half sine shock on random control method for multi-axial vibration testing

Control method for the multi-axial half sine shock on random vibration test is studied in this article. From the Fourier spectrum analysis, it is found that the power of the half sine shock is mainly concentrated within a specific frequency band, which is only related to the sine frequency of the half sine shock. Compared with the broadband random signal, the frequency band occupies a small range. Therefore, a mixed signal separation method is proposed for the shock on random vibration control test. Firstly, the Fourier spectrum is divided into two parts, and then the Empirical Wavelet Transform (EWT) is used to extract the shock component from the mixed signal. Afterward, the random component is obtained by subtracting the shock component from the mixed signal. According to the deviations between each component and the specified references, the amplitudes of the shock component and the Power Spectral Densities (PSDs) of the random component are controlled by the amplitude correction algorithm and the matrix power control algorithm, respectively. An experiment with tri-axial shaker is implemented and the results show that the proposed method is feasible for the multi-axial half sine shock on broadband random vibration control test.