Using of Entropy Method in Failure Diagnostics

Occurring of failure is accompanied by changing of energy distribution of vibroacoustic signal generated by a dynamic system. Hence, comparing the energy distributions of signals observed for technical conditions without failure and for failure states of dynamic model one has access to information about the formation and development of damaging process. The tool to estimate the probability distribution changes corresponding to changes in the distribution of signal energy can be failure oriented measure of information. The paper discusses the problem of proper selection of entropy methods, for detecting and the identification of the failures, both for the signals generated by the actual dynamic systems and simulated one. Particular attention was paid to the possibility of using bispectral entropy and singular entropy change for example signals generated during the formation and propagation of the gear tooth crack. The next interesting resultants of analyzing changes was in the entropy energy of vibration signal recorded during the tests on the back to back test-bed. It was given the observation the chosen harmonic and its modulated bands. During analysis we determined energy change as a function of time in the bands of different widths around the successive harmonics engagement. On the basis of such a limited energy of signal, the technical state of entropy was calculated.