Skliarov V. Development of methods for measuring the characteristics of complex mechanical and thermophysical systems based on computer simulation

The thesis presents new solutions to the important scientific and applied problem of improving the accuracy of research results of mechanical and thermophysical characteristics of complex systems based on the synthesis of measurements, analytical calculations and computer simulation. The complex systems are considered as a set of interacting, functionally independent subsystems designed for safe operation of an industrial facility, including technical devices with measuring functions operated at energy generating facilities, or are the part of the national measurement standards of Ukraine. The analysis of modern computational complexes is carried out according to the problems they solve. It is established that the work of many computer simulation programs is based on the finite element method, which is a numerical method for solving differential equations with partial derivatives, as well as integral equations that arise when solving scientific problems of applied metrology. The application of computational complexes for solving hardness measurement and heat transfer problems is investigated. The scientific approach to the research of additional components of the uncertainty budget in measurement simulation is developed. In contrast to the existing approximate methods of peer review, the integrated calculation and experimental method based on a combination of modern computer programs and the results of experimental studies of complex systems is proposed, which allows the evaluation and prediction of their condition. In contrast to the existing methods with insufficient detail of the target of study, the quality criteria of developing a finite element model of a complex system by modern calculation complexes are investigated, which allows to increase the accuracy of simulation results. It is proposed to take into account additional factors in the measurement equation and the uncertainty budget of the results of hardness measurements, which increases the accuracy of evaluation of the degree of equivalence of the national measurement standard of hardness units on the Rockwell and Super-Rockwell scales when performing international comparisons. By introducing the nonlinearity factor of substitution non-equivalence in the model solution of the temperature field, the method of calculation of the calorimetric transducer of laser radiation is improved, which allowed to increase the accuracy of measuring the power and energy of laser radiation. The methodology for predicting the mechanical properties of materials using simulation and experimental study of methods for measuring the hardness of material samples is improved, which, in contrast to the existing method of assessing NPP equipment, provides for the prediction of aging and the study of critical components of the equipment, that allowed to increase the reliability of the assessment of the thermomechanical equipment of NPPs. Model solutions are further developed in the study of the properties of modern polymeric materials obtained using additive technologies and the properties of new polymeric materials are obtained, which makes it possible to model the behavior of polymeric materials depending on the influencing mechanical factors.