Search academic texts

Information × Registration Number 0225U001343, (0122U001729) , R & D reports Title Development of calculation methods for determining the residual lifetime of structural elements under maneuvering load and aggressive environments popup.stage_title Розроблення розрахункових методів для визначення залишкової довговічності елементів конструкцій за маневрового навантаження та агресивних середовищ Head Andreikiv Oleksandr Ye., д.т.н. Registration Date 29-01-2025 Organization Ivan Franko National University of Lviv popup.description1 The aim of the work is to develop an energy approach to determine the kinetics of cracks propagation in solids and on this basis to create calculation methods for determining the residual lifetime of structural elements subjected to long-term maneuvering load, high temperatures, hydrogen and corrosion environments. popup.description2 A previously unknown phenomenon of abrupt movements of blast furnace walls of flooded ferritic-pearlite steels during their quasi-static magnetisation, depending on the hydrogen concentration in them, was established, which consists in the fact that with an increase in hydrogen concentration, the amplitude and number of abrupt movements of blast furnace walls increases, and when the hydrogen concentration reaches the value characteristic of this material, it decreases (Officially, this scientific discovery is registered with the Association of Authors of Scientific Discoveries of Ukraine, Diploma No. 5/442). The paper describes the scheme of the technology developed by the authors for manufacturing rifled tank barrels with an increased resource of targeted damage. Important components of this technology are the authors' proposed strengthening of the inner surface of the barrels by surface hardening with high-frequency currents and grinding of surface microcracks that appear as a result and can serve as sources of barrel fracture. Mathematical models (differential equations with initial and final conditions) have been constructed to describe the kinetics of crack propagation in materials (with known characteristics of the medium and materials) under long-term static, cyclic and manoeuvring loads, high temperatures, hydrogen-containing and corrosive environments, and neutron irradiation. These models are based on the first law of thermodynamics for the elementary act of crack propagation in a solid under mechanical loading and the influence of the above physical and chemical factors, as well as the basic principles of the physical and chemical mechanics of material fracture. On the basis of the models, computational methods for determining the period of pre-critical crack growth in structural elements (determining their residual life) under the influence of the above-mentioned physical and chemical factors have been developed. Using the developed methods, the residua Product Description popup.authors Blahitka Marta Ya. Dolinska Iryna Ya. Zviahin Nikita S. Nastasiak Sviatoslav V. Slobodian Mykola S. Sulym Heorhii T. popup.nrat_date 2025-01-29 Close