The use of an acoustic signal in diagnosing a cross crack in a cantilever beam

The results of experimental investigations are described on the basis of which a method of diagnosing the formation and growth of a cross crack in a cantilever beam is developed. The diagnostic criterion is the nonlinear distortion factor calculated as the ratio of the rms value of the higher harmonic amplitudes to the rms value of the amplitude of the investigated acoustic signal. It is established that, by using this factor, it is possible to detect the initiation of a cross crack in a cantilever beam, observe the change in the beam structure within the period before its fracture, and monitor the crack's development. (C) 2000 MAIK "Nauka/Interperiodica".