Вимірювальна техніка та метрологія
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Item Моделювання та якість моніторингу діагностичних систем(Видавництво Львівської політехніки, 2015) Чабан, Олеся; Юзевич, ЛарисаРозроблено рекомендації щодо поліпшення якості математичних моделей моніторингу складних об’єктів техніки та медицини з низьким рівнем динаміки процесів, що характеризуються особливостями раннього виявлення кризових (передаварійних) ситуацій. Разработаны рекомендации относительно повышения качества математических моделей мониторинга сложных объектов техники и медицины с низким уровнем динамики процессов, которые характеризуются особенностями раннего выявления кризисных (предаварийных) ситуаций. The example of improvement of the mathematical model of monitoring of difficult objects of technique and medicine with the low level of dynamics of processes is examined. The article of researches is normative documents, which should be expediented to specify and perfect on the basis of thein formation, got as a result of analysis of results, mathematical models of monitoring of difficult objects of technique, medicine got with a help with the low level of dynamics of processes. An aim of the put article is an evaluation of quality of theim proved mathematical model of monitoring of difficult objects of technique, medicine with the low level of dynamics of processes. As an example, the diagnostic system of the corrosive monitoring of pipelines (SCMP) is examined, the methodologies described and regulated by a state standard are fixed in basis of functioning of that. Facilities of SCMP are diagnose the stress corrosive spalling of pipelines, that is initiated and develops as defects on the external surface of pipe at using of isolating coverage and cathode defence for simultaneous influence of the mechanical loading and corrosive-active environment. A corrosive environment is designed by an aquasystem with the different value of pH-value. The criterion of damage of sheeting the methods of measuring of protective and polarization potentials is a jection of electric potential, that is compared to the value, set corresponding normative document. It is suggested to use methodology of control of constituents for slushing coverage on the stage of making of steel pipes with coverage on the size of regional corner of moistening. Coverages can be metallic, dielectric. In particular, the three-stratified polyethylene coverage is used in the last time. On the size of regional corner of moistening it is possible to estimate adhesion of coverage, in particular, work of adhesion and energy of adhesive bonds. The criterion of adhesion strength for coverage (metallic or dielectric), that is expressed through the critical values of power descriptions of interface layer on the border of metal of pipe with coverage is introduced. The methods of scientific researches are constantly developed and improved. Therefore in course of time standards need additions, id est bringing of new more actual information. Touches such type of addition integral criterion of evaluation of biocorrosive aggressiveness of soils, that takes into account exceptelectro-resistance also a quantity most corrosive dangerous groups of microorganisms and elements of chemical composition of soils. Possible penetration of oxygen, water and other substances is through sheeting. As a result there is a hasp of passive tape with formation of local cells of corrosion – pitting. Pitting of transformed in microcrack, and on the finishing stage one of microcracks initiates distribution of main crack. Procedure of calculation of durability and longevity of pipeline is offered at presence of defects as a cavity there is pitting in the top of that. Methodologies of calculation of durability of steel pipes at presence of defects are complemented by the criteria of durability, that in the models of SCMP was not examined before. The first criteria represents connection of threshold value of coefficient of intensity of tensions of К1SCC with work off lowage in a calculation on unit of the accrued surface at distribution of crack of PPL and overstrain of anodic reaction z of corrosive dissolution. The parameter of PPL is included in the known formula (criterion of durability) of Griffits-Orovan, that it is also suggested to be used. The criterion of Griffits-Orovan binds the limit of fluidity (to durability) of metal to length of crack, by the Young’s module and by the Poisson’s ratio of material. The system of mathematical correlations of SCMP is suggested to complement correlation for the closeness of current of ia in the top of pitting, that is expressed through a corner in the top of pitting, conductivity of electrolyte, dependency upon resistance change of potential between anodic and cathode parts. This correlation is set forth as a criterion of corrosive firmness of pitting. The model of SCMP is complemented by criterion correlation for determination of speed of remaining corrosion of metal (id est closeness of Ik of corrosive current) in the defect of isolating coverage, polarization potential and potential of corrosion of metal of pipeline are included in that. The new entered criteria of durability and corrosive firmness complement, specify and perfect SCMP and can be used for control of corrosive process and development of recommendations of slushing defence. With their help optimization of terms of defence of elements of constructions of metallic underground pipelines can be conducted. The compatible use of the new entered criteria allows in detailen ough from positions of electrochemistry, physics of superficial processes and mechanics of destruction to study the mechanisms of distribution of corrosive cracks in main pipelines that are in aggressive environments. Monitoring quality is characterized by quality of measuring and recreation of information, in particular: by exactness, comparativeness, authenticity, operationability, stability of estimations of parameters, that is included in the new entered criteria. Recommendations in relation to upgrading of mathematical models of monitoring of difficult objects of technique and medicine with the low level of dynamics of processes touch protective potentials, them uncertainty and gradients. An algorithm that is base on the use of the new entered criterion correlations and allows to optimize oscillation of protective and polarization potentials in time is offered in the system of the corrosive monitoring of underground pipelines, that it is necessary for the correct evaluation of corrosive activity of soil and speed of remaining corrosion of metal of pipeline. Corresponding results give an opportunity to forecast the change of the corrosive state of metal of pipeline in course of time and to expect the resource of capacity of local area and all pipeline on the whole. The indicated innovations will help to perfect normative documents, in particular, standards that touch anticorrosion defence.