G.V. Karpenko Physical-Mechanical Institute

The feasibility of using a combined method for the separation of powdered polymers activated by dispersed metals is established. Vibration, together with the transfer of the studied polymer mixture to a fluidized state, can more effectively separate the mixture into fractions with different metal contents. The design of the installation makes it possible to unload individual fractions of the mixture for their further analysis, which is important for laboratory research. The fatigue life of thin-sheet specimens made of powdered polyvinyl chloride activated with dispersed zinc under pure bending, is studied. Fractographic features of fractures are identified.

The regularities of the coating formation in an alkaline electrolyte by the method of plasma electrolytic oxidation on the titanium surface previously nitrided by gas and plasma methods were investigated. It was established that such complex treatment allows formation of the hydrophilic porous hydroxyapatite coating with a thickness up to 100 m and a Ca/P ratio closer to biological hydroxyapatite.

This article focuses on the mathematical modeling of residual life assessment for structural elements subjected to prolonged static loads, considering the operational degradation of their materials in corrosive environments. The residual life of a structural element is defined as the operational time remaining after the detection of a crack-like defect. The acoustic emission method and an energy-based approach are used to develop a mathematical model. The energy-based approach relies on a mechanical analogue of the first law of thermodynamics, considering the balance of energy components and the work done by external forces, along with the rate of change balance during an elementary crack propagation increment. It is proposed that the crack size and the loading parameter in its vicinity be determined from the acoustic emission signal parameters acquired from the monitored structural element during crack growth. The proposed model was applied to assess the residual life of an X70 steel plate after 33 years of service.