539.4

stresses, deformation, hydrogen concentration, finite elements method, backward Eulermethod, virtual work principle, cylindrical samples. 

In most cases the metal structures service under operating conditions results in the fact that these structures or their certain elements are constantly affected not only by mechanical factors (load, residual stresses, etc.), but also by the environment. Elements of pipelines, load-bearing sections of thermal and hydroelectric power stations, metal structures of bridges are all influenced by the environment that fills or surrounds them. Such environment depending on the content of acids and alkalis, a number of hydrogen-containing media can be corrosive. It should be also noted that the influence of such corrosive environment and mechanical factors influence are simultaneous and interrelated resulting very often in brittle or quasi-brittle metal fracture. Therefore, the problem of estimating the basic metal structures engineering parameters (strength, reliability, etc.) that are corroded by the simultaneous action of mechanical force factors, is currently an important problem of industrial operation. The problems of hydrogen interaction and stresses in metal structures are still not sufficiently investigated. While hydrogenating the metal body, the linear dimensions of its elements and volume change. At the same time, changing body volume, under certain conditions, causes internal stresses. Let us assume that the interaction between hydrogen atoms is negligible. It is necessary to establish the stress-strain state of the metal body due to the hydrogen concentration in it. Stresses in the body also occur due to external loads . According to the classical theory of elasticity, stresses of such nature cause the corresponding elongations and displacements. Therefore, stresses cause deformation. According to the superposition law, the increase in total deformations is equal to the sum of deformations caused by the change in the hydrogen concentration and deformations caused by stresses in the body.

1. Glukhova Zh. L., Goltsov V. A., Schegoleva T. A. et al. Mathematical modeling of hydroelastic effect of slowing down of diffusion processes in metal-hydrogen system. Int. J. Nucl. Hydrogen Prod. App-2008. № 4. P. 334–342.
2. Goltsov V. A., Glukhova Zh. L., Lyubimenko E. N. et al. Vodorodnyje koncentracionnyje naprjazenija: priroda, eksperimentalnyje projavlenia, znachimost’ dlja techniki. Metalurhija. 2009. Vyp. 11 (159). P. 165–173. [Іn Russian].
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4. Panasyuk V. V., Ivanyts’kyi Ya. L., Hembara О. V., Boiko V. M. Influence of the stress-strain state on the distribution of hydrogen concentration in the process zone system. Material Science. 2014. 50. № 3. P. 315–323.
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In most cases the metal structures service under operating conditions results in the fact that these structures or their certain elements are constantly affected not only by mechanical factors (load, residual stresses, etc.), but also by the environment. Elements of pipelines, load-bearing sections of thermal and hydroelectric power stations, metal structures of bridges are all influenced by the environment that fills or surrounds them. Such environment depending on the content of acids and alkalis, a number of hydrogen-containing media can be corrosive. It should be also noted that the influence of such corrosive environment and mechanical factors influence are simultaneous and interrelated resulting very often in brittle or quasi-brittle metal fracture. Therefore, the problem of estimating the basic metal structures engineering parameters (strength, reliability, etc.) that are corroded by the simultaneous action of mechanical force factors, is currently an important problem of industrial operation. The problems of hydrogen interaction and stresses in metal structures are still not sufficiently investigated. While hydrogenating the metal body, the linear dimensions of its elements and volume change. At the same time, changing body volume, under certain conditions, causes internal stresses. Let us assume that the interaction between hydrogen atoms is negligible. It is necessary to establish the stress-strain state of the metal body due to the hydrogen concentration in it. Stresses in the body also occur due to external loads . According to the classical theory of elasticity, stresses of such nature cause the corresponding elongations and displacements. Therefore, stresses cause deformation. According to the superposition law, the increase in total deformations is equal to the sum of deformations caused by the change in the hydrogen concentration and deformations caused by stresses in the body.