Okrepky Y. Acoustic emission diagnostics of fracture of brittle inclusions

Fields of elastic waves induced during fracture of brittle inclusions in quasistatically loaded solids. To develop a method for quantitative evaluation of fracture of brittle inclusions employing the parameters of elastic waves of acoustic emission. There were used the fundamental solutions of the problems from elasticity theory, mathematical modeling, spectral analysis of AE signals, physical experiment. There were suggested analytical relationships for determination of sizes of brittle inclusions of the elliptical and plate-like form incorporating strain relaxation time during the period of their fracture. There were calculated the values of stress both in the matrix and in the inclusion during the loading of the real body. There were experimentally found and theoretically confirmed that the AE signals generated during the early stages of loading accompanied the fracture of brittle inclusions. It was determined that the value of stress intensity factor is invariant with respect both to the thickness of the samples and the type of loading. The results of this work were used for AE diagnostics of the containers for storing liquid and dry substances in the seaport of Odessa and water-circular vacuum pump VVN-50 at VAT "Horokhiv sugar mill". The results of this study could be used for: further development of the theory of strength and linear fracture mechanics pertained to the solids with brittle inclusions; improvement of the existent methods of AE diagnostics of controlling objects; generalization of the certain statements related to the AE-signal selection.