Hembara O. The methods of calculation of residual life time of structural elements under hydrogen-containing environment effect

Object of investigation - fracture of structural elements materials under effect of hydrogen-containing environment. Aim - construction of calculation models and development on their bases of the methods for assessing residual lifetime of structural elements with cracks, taking into account different mechanisms of hydrogen effect. Methods of investigation - finite element method, method of Laplase integral transformation in time, method of asymptotic equivalent functions and the method of boundary interpolation , the equivalent areas and Runge-Kutta methods. A number of new calculation models of crack propagation in metals under different mechanisms of hydrogen effect were formulated and based on them the methods of calculation of the residual lifetime of structures under effect of hydrogen-containing environments, with account of peculiarities of hydrogen effect on crack propagation, were developed. Residual lifetime of such structures as a pipeline with an internal semi-elliptical crack and a high-pressure gas vessel with a surface crack under long-term static loading, vessel of the oil hydrocracking reactor with a sub-surfacing crack subjected to non-stationary temperature effects, a section of gas pipeline with an internal blister under effect of hydrogen sulphide medium and with an internal crack in the conditions of soil corrosion was predicted. Investigation results have been used at "Izhorskie zavody" company (Russia) for optimization of the technology of protective films application on the vessel of oil hydrocracking reactor and at " Ukrtransgaz" State company for prediction of the residual lifetime of the main " Urengoy-Pomari-Uzhgorod" gas pipeline section. Branches of application - power generating, oil-chemical and oil-processing.