Page 6 - Дисертація Сапужак Я.І

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hydrogenation. The subject of the research is mathematical models and methods for

estimating the strength and durability of structural elements under the action of a

hydrogen-containing environment and long-term high-temperature load.

The thesis presents an analytical review of recent models and methods for

evaluating and ensuring the strength and durability of power equipment elements. It

has been concluded that the existing models and methods do not take into account the

specific features of the influence of hydrogen on the mechanical properties and

accumulation of damage in the metal, especially under long-term high-temperature

loading. This is because predicting the behavior of structures over time to determine

their durability under constant or variable operating conditions becomes a very

complex problem of modeling the flow of a set of different processes going at

different speeds at different points of the structure and requires special algorithms for

their solution. Considering the analysis, the thesis sets and solves an important

scientific and technical task for the energy of Ukraine for predicting the strength and

durability of structural elements of power equipment, taking into account their

possible hydrogenation. The method of conducting research and the mathematical
apparatus used in the research is substantiated. Methods of mathematical modeling

are based on the approaches of the mechanics of deformable body and energy criterion
of fracture.

Methodology and software for assessing the strength and durability of
structural elements in terms of complete control and management of material state for

long-term operation based on the energy approach were improved. The developed

mathematical models and the developed algorithm for their realization using an

estimation of results of conducting and the corrosive environment of accumulation of

harmful processes in metals at the expense of influence on the base of the energy

approach are improved. For the first time, the stress-strain state and the duration of

the rectilinear section of heat exchange pipes of three types of steam generators made