SHAKER SIMULATION OF RANDOM VIBRATION WITH A HIGH KURTOSIS VALUE

This paper presents a vibration test technique for extending the tails of amplitude probability distribution beyond the Gaussian values as i s characteristic for vibration of ground vehicles on a rough road or t errain. The method proposed uses the commonly accepted approach of app lying pseudorandom excitation in the form of a Fourier expansion. The procedure described in this paper can be implemented by updating curre ntly available digital vibration controllers. The solution for amplitu de domain fitting is based on an analytical expression derived for the kurtosis parameter of the polyharmonic process in terms of amplitudes and phase angles for any number of harmonic components. The results o f theoretical analysis are embodied in software subjected to verificat ion in computer and experimental tests. Even with additional kurtosis control, the closeness of the generated and desired spectra is the sam e as for the Gaussian simulation of power spectral density. Hence, thi s new technique for amplitude domain matching is not accompanied led b y the deterioration of ordinary test capabilities in the frequency dom ain.