Page 9 - dyser_Stankevych

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energy parameter E WT  1 , 0 – to the brittle fracture (macrocracking). Using this

criterion it is possible to correctly identify of the fracture types, which helps to increase

the efficiency of AE-diagnostics of structural elements in real time.

Based on the new criterion the applied method of identification of fracture types of
aluminum, aluminum alloys and their welded joints has been developed. Using energy

criterion it has been established that fracture of technically pure aluminum is ductile
with the formation of a large number of the slip bands and the deep pits on the surface.

During fatigue fracture of aluminum alloy 1201-T dominates the brittle fracture which
alternates with plastic deformation and microcracking. The sources of the AE signals

during fatigue fracture of aluminum alloys and their welded joints under quasistatic

loading were identified by energy criterion and fractographic research.

Based on the research results it was shown that the identification of the fracture

types using the energy parameters of the WT of the AE signals makes it possible to

correctly determine the start of the low-temperature creep cracks.

A new method for the identification of the fracture mechanisms of fiber composite

materials based on the energy parameters of continuous and discrete WT has been

developed.

An express method of qualitative ranking of dental polymers and prosthetic

constructions based on the parameters of their brittleness using of the energy criterion of

continuous WT has been created. Experimental investigations have shown that jump-

like macrofracture of the brittle dental materials had been accompanied by microplastic

acts, that was confirmed by the generation of corresponding AE signals. It is established

that the strength of prosthetic tooth-endocrown constructions depends on the strength of

the base (tooth), where the fracture initiates. The fracture of the zirconium dioxide

endocrown confirms this conclusion. The zirconium specimen on the rigid basis has not

fractured although. The construction with metal ceramic endocrown has the least risk of

early fracture during clinical application.

The method of estimation of the state of local hydrogen degradation of materials

using energy and frequency parameters of WT of MAE signals has been created. The

analysis of local features of continuous WT of MAE signals made it possible to obtain