Failure-free Operation Research Articles

Analysis of research on smart rail circuits

The purpose of the article is to study intelligent continuous-type rail circuits with current receivers, respectively, to identify the possibility of determining the unit located on the rail lines with a standard shunt prescribed in the operating rules, as well as monitoring for breakage of a continuoustype rail circuit. To study smart railway circuits, it is necessary to take into account the circuit diagram of this track circuit and its operation with various factors influencing it. One of the points of the study is to determine the maximum and minimum resistance at the beginning and at the end of this rail line and also taking into account the worst influencing parameters on an intelligent rail circuit of unlimited length, carry out calculations and determine on the graphs the probability of failure-free operation in all modes. The study took into account fluctuations in temperature decline, both during the seasons, winter, summer, etc., and sharp continental changes within an hour in operating mode. When conducting the study, we also took into account the insulating resistance that affects the power supply of the composition determination sensor, which leads to a dependence on the length of the smart sensor. The parameters of changes in the sensor supply voltage, its variability from the supplier and the resistance of the rails and their fluctuations were taken. For this purpose, the requirements for the length of the intelligent rail circuit, shunt resistance and insulation resistance used on the road were applied, as well as determining the influence of all unfavorable conditions.

Evaluation of operational reliability of diesel fuel system elements

In the article, as a result of a review and analysis of studies on the reliability of elements of the power system of diesel engines, it was determined that the cause of most failures of elements of the power system is the presence of impurities and water in the fuel, and the use of a defective fuel filter. The purpose of the study is to assess the degree of reliability of elements of the power supply system of diesel engines under normal operating conditions. For this purpose, an observation program has been drawn up for a group of intensively working tractors. Taking into account apriori information, the following elements (nodes) were selected as observed elements. P1—fuel tank and fuel lines, P2—settler filter, Pz— high pressure fuel pump; P4 – fuel nozzle. The observation results were subjected to statistical processing and the probabilities of failure-free operation of each element were constructed. The correlation dependence of failure-free operation between the observed elements of the power system was assessed. To assess the actual reliability, the main statistical characteristics of the time between failures of the elements of the power system of the diesel engines of the tractors participating in the experiment were calculated. Graphs of the distribution of time between failures of power system elements were constructed, conclusions were drawn regarding the reliability and service life of the elements.

A new method for assessing the reliability of multi-purpose vehicles based on test results in extreme conditions

The article presents materials on methods and means of reducing testing time and improving their quality in terms of accuracy, reliability and reproducibility of results, regardless of changing road, soil and climatic conditions using a new reliability indicator: instead of average time between failures — time to 1st failure with probability of failure-free operation is 0.95. A method is presented for assessing the reliability of test results with different volumes of mileage in extreme road conditions by comparing normal test data with a reference scientific and methodological platform. Keywords multi-purpose vehicles, road tests, reliability, failure, method, reliability assessment

METHOD OF DETERMINING THREE ACOUSTIC SENSORS FOR REGISTRATION THE BALLISTIC WAVE OF AN ARTILLERY SHOT

Abstract. The paper is dedicated to the development of the method of identifying acoustic sensors for registering ballistic and muzzle waves of an artillery shot. The proposed method allows solving the problem of selecting three acoustic meters from the existing set in the firing zone, which are the most suitable for implementing effective registration of ballistic and muzzle waves of a shot, taking into account their location, measurement error, and the probability of failure-free operation. Keywords: artillery shooting, verification of shots, ballistic wave, method of identifying acoustic sensors

АНАЛИЗ ПОКАЗАТЕЛЕЙ НАДЕЖНОСТИ ЭЛЕМЕНТОВ СИСТЕМЫ ВЕРХНЕГО ПРИВОДА ПРИ ЭКСПЛУАТАЦИИ НА МЕСТОРОЖДЕНИЯХ ЗАПАДНОЙ СИБИРИ

Oil and gas companies carry out routine and major repairs of wells using mobile drilling complexes equipped with top drive systems (TDS) in order to increase the fl ow rate of oil and gas wells. Statistical data on the operation of more than sixty TDSs in the fi elds of Western Siberia were collected and analyzed. The TDS’s main reliability indicators, such as the probability of failure-free operation and the failure rate, were calculated. The fi ndings can be used to improve drilling equipment maintenance and repair procedures. The insuf fi cient level of reliability of the TDS elements, along with intense operating conditions in the fi elds of Western Siberia, causes failures and halts the entire technological process of well repair, necessitating the need for repair and renewal operations. The fi rst priority of oil and gas companies lies in increasing the TDS reliability based on the high requirements for the reliability of drilling equipment operated at hazardous production facilities, as well as driven by the purpose of continuous operation on routine and major repairs of wells.

FAILURE MODEL OF NON-RESTORABLE COMPLEX TECHNICAL OBJECT OF MILITARY EQUIPMENT

Maintenance (MT) is a necessary component the process of operating a complex technical object of military equipment, intended for long-term operation in wartime and harsh operating conditions. The volume, content and timing of maintenance must be completely determined by the reliability properties of the object, conditions and modes of its use. Effective implementation of any maintenance operation is possible only if the design of the object provides special means for this purpose (for measuring the defining parameters) and ensures the accessibility and convenience of performing the operation. Complex technical objects in modern society are extremely important. Such objects belong to the class of restored objects long-term repeated use. They are usually expensive and require significant operating costs. To ensure the required level of failure-free operation during their operation, maintenance is usually carried out, the essence of which is the timely preventive replacement of elements that are in a pre-failure state, which is very important for military equipment. A characteristic feature of complex technical objects for special purposes (military equipment) is the presence in their composition of a large number (tens, hundreds of thousands) different types of components that have different levels of reliability, different patterns of their wear and aging processes. This feature requires a more subtle approach to organizing and planning maintenance during operation (of military equipment). The above statements fully justify the conclusion about need to determine the main characteristics of the maintenance system in early stages of its design, when it is still possible to make changes to design of the object. In this work, a model of failure-free operation non-repairable complex technical object of military equipment is developed. The work also confirms the general idea that data obtained fully confirm the assumption that a maintenance strategy that is not restored is more preferable in the case of unreliable (inaccurate) information about the reliability indicators of elements of a military equipment object.

Influence of the temperature schedule of heating network and using differential pressure regulators on the reliability of heat supply systems

The methods of increasing reliability of heat supply systems are analyzed. A digital twin of the existing heat supply system has been created. Various modes operation of the system are modeled and control and decision-making system in the conditions operation of the heat network is considered on the example of one of heat supply systems of the Republic of Tatarstan. The indicators of reliability of heat supply to consumers at using these methods are determined. As a result of the application of control methods and increasing reliability of the thermal power systems, probability of failure-free operation and the coefficient of hydraulic stability of heat supply system were calculated, the influence of the temperature schedule and the use of differential pressure regulators (DPR) on the reliability of the system in general were analyzed. Special attention is paid to the hydraulic balancing of the heat supply system to increase her reliability.

МЕТОДИКА ОЦЕНКИ ЭФФЕКТИВНОСТИ ПРИМЕНЕНИЯ ПРЕДУПРЕДИТЕЛЬНОГО РЕМОНТА ДЛЯ ЗАДНЕГО МОСТА АВТОБУСА

The efficiency of operating commercial vehicles is analyzed. Statistical results of failures of parts of the rear axle of the bus are presented and graphs of the probability of failure-free operation of the units are constructed. It is noted that fuzzy formalization will be used in the rear axle reliability model. A technique has been proposed to increase the technical readiness coefficient of the bus. The results of calculations of the technical readiness coefficient are presented, from which it is clear what contribution each detail makes to its change.

Алгоритмы оценки основных параметров надежности низковольтного оборудования схем цеховых сетей

The article presents the classification of fuses, breakers, circuit breakers and packet switches. The laws of change of probabilistic reliability characteristics of the studied devices, as well as low-voltage cable lines are determined. Types of functions of change of basic reliability parameters are determined and corresponding graphical dependences are shown. The comparison of the obtained results of the values of probability of failure-free operation time with the requirements of GOST and passport data is carried out. The investigated probabilistic parameters of lowvoltage devices and cable lines are checked for compliance with the accepted law of distribution of random variables.

Исследование показателей надёжности многокомпонентной эргатической системы с учётом надёжности человека-оператора

The article substantiates the need to monitor the reliability of the human operator of the ergatic system, and also proposes a software application for assessing the corresponding indicator. The paper presents the results of an experimental study of the probability of failure-free operation of ergatic systems depending on the frequency of failures of the human operator.

Towards reliability of load-bearing beams of bridges (Tomsk)

One of the criteria for assessing the reliability of load-bearing elements of bridges, are peak values of the temporary mobile load significantly exceeding the standard level of loading. Peak loads are interpreted as a continuous random process in the form of a random pulse sequence manifested after a random period of time and having a random duration.Purpose: The aim of the paper is to show changes in temporary mobile load over time in the form of a simple Poissonian flow, where the bridge load is independent, and repeatability and duration of the random load are independent random variables.Research findings: Three cases are considered to determine sufficiently low probability of destructive temporary mobile loads during the given normative service life of bridges. Based on the failure types, the average failure-free operation of the beam is determined as well as the operating time for a possible failure with a prolonged or specific excess load.

Methods for assessing the reliability of in-shop power supply

Research activities in the field of development of electrical power and electrical equipment include the development of new approaches to assessing the reliability indicators of electrical equipment elements and in-house power supply systems in general. The study has examined methods for assessing the reliability of electrical equipment in intra-shop power supply systems using the example of a workshop network section, including its main elements: power transformer, low-voltage cable lines, distribution points, circuit breakers, magnetic starters, contactors, switches. The reliability parameters of the circuit are calculated relative to the distribution cabinet of the power (DCp) and the distribution point of the power (DPp); regarding each connection of DCp and DPp. The methods under consideration are recommended to be used to clarify the frequency and timing of maintenance and repairs of electrical equipment of the in-shop power supply system, as well as to analyze the reliability of operation and identify the least reliable sections of network diagrams. The presented calculation using the logical-probabilistic method by constructing a fault tree is advisable to use to estimate the frequency of power loss of DCp and DPp, as well as individual connections. For the studied circuits, graphical dependences of the probability of failure-free operation of electrical equipment and the occurrence of a failure over time have been constructed.

Increasing the Efficiency of Diagnostics in the Brush-Commutator Assembly of a Direct Current Electric Motor

Increasing the productivity and reliability of mining infrastructure facilities is an important task in achieving future goals. Mining dump trucks are an important part of coal mine infrastructure. In this article, to determine the reliability indicators in a brush–commutator unit and the residual life of electric motor brushes, a mathematical model for processing statistical data has been developed, which allows for the classification of types of failures and, unlike existing models, the determination of the life of the brushes according to the maximum extent of their wear. A method for predicting the residual life of an electric brush in a DC electric motor is presented, which contains a list of controlled reliability indicators, included a mathematical model. The described model improves the accuracy of the prediction and detection of DC motor failures. The derivation of the general formula for calculating the residual life of electric brushes is given. Based on the proposed mathematical model, we studied and calculated the reliability of the brush–commutator unit, the minimum height of the brush during operation, the average rate of its wear, the standard deviation and the mathematical expectation of brush wear. A nomogram of the failure-free operation time of the brush–commutator unit in a DC electric motor was modeled using the height of the brush during operation. Output parameters after the implementation of this monitoring system include the reliability of the electric motor operation. At the same time, diagnostic characteristics are improved twofold, and the residual life of the brush-switching unit is increased by 28–30%.

Distributed Data Proceeding Systems Architectures Resource Efficiency Improvement on the Basis of Apriory Data about the Jobs Late Completion Times

Purpose of research. The purpose of this study is to develop a method for improving the efficiency of distributed architectures of data processing systems operating in the fog and edge layers of the network. In conditions of high dynamics of both the network infrastructure and the load, the task of forming the architecture of data processing systems is solved regularly (migration of virtual machines, horizontal scalingб etc.) At the same time, the issue of the consumption of the residual resource of computing nodes is practically not considered, while the often used devices have relatively low capacity, and their high workload leads to a reduction in the service life. Therefore, the creation of methods for forming an architecture of a computing device system that is effective in terms of saving a computing resource is an urgent task.Methods. The main scientific methods used in this study are domain analysis, operations research methods, optimization methods and computer modeling, confirming the feasibility of the main aspects of the developed method. To improve the efficiency of placing computational tasks on the nodes of a network fragment, this paper formulated a multicriteria optimization problem, where each element of the vector objective function corresponds to an individual value of the probability of failure-free operation of a computing device. To obtain estimated values of the cost function, a priori estimates of the late completion of the solution of computational problems by nodes are used, since the resource allocated for solving depends on the allocated time, and the time for solving the problem, respectively, on the allocated computing resource. The value of the cost function is calculated on the basis of approximate a priori estimates, which leads to a positive effect in terms of the consumption of computing resources of devices.Results. The result of the study is a developed method for improving the efficiency of distributed architectures of data processing systems operating in the fog and edge layers of the network.Conclusion. The method proposed in this work allows to choose such a load distribution in order to reduce the workload of devices and thus reduce the consumption of computing resources of the devices.

MODERNIZATION OF MOVEABLE CONNECTIONS OF THE SECTION OF THE SOWING COMPLEX

The efficiency of planting seeds and, therefore, the yield of agricultural crops depend significantly on the characteristics of the mechanisms of copying sowing sections. These mechanisms can be conditionally divided into two categories: radial and parallelogram. Radial mechanisms with leashes are used in traditional technologies and require high-quality preliminary processing, and radial mechanisms with pressure rods are suitable for any agrophones The durability of the movable joints of the parallelogram copying mechanism of the sowing complex depends on their resistance to wear. This stability is determined by the mode of operation, chemical composition and structure of the surface layer of parts, as well as physical-mechanical and tribotechnical characteristics. With an average seasonal task for Agro-Soyuz Turbosem II 19-60 sowing complexes within 3–4 thousand hectares, the total service life of experimental parts is at least 4 years, which is at least four times more than in the case of serial parts. The positive effect of the absence (or the presence within the measurement error) of wear of steel parts of movable joints that work in connection with polymer composite material (PCM) was revealed. The average resource of experimental parts in the hinges of the parallelogram copying mechanism for Agro-Soyuz Turbosem II 19-60 seeding complexes is 20589 ha. The average value of the wear of the experimental parts was determined to be 1.78 mm, and the intensity of their wear was 1.02×10-4 mm/ha. It was established that the wear of UPA-6-30 PCM parts in the moving joints of the copying mechanism occurs according to the normal distribution law ( = 0.108), which allows very accurate prediction of their resource. The consistency of the experimental distribution with the theoretical distribution was checked using the Kolmogorov criterion. It is confirmed that the distribution takes place according to the normal law. An analysis of reliability indicators during shortened tests was also carried out and the probability of failure-free operation of experimental parts made of polymer-composite material was determined. According to the results of field tests of the elements of the movable joints of the mechanism of copying the sowing complex, it was established that the resource value of 20,558 hectares exceeds the indicators of serial parts by 4 times.

INCREASING THE RELIABILITY OF ELECTRIC POWER FACILITIES THROUGH THE USE OF UNMANNED AERIAL VEHICLES

The issue of increasing the reliability of the operation of facilities in the energy system of Ukraine is being considered. It is shown that the electric power complex of Ukraine has significant levels of depreciation, which, in turn, leads to an increase in the number of emergency conditions, an increase in the time of post-accident recovery, and as a result, a decrease in the reliability of power supply in general. Accordingly, the loss of electrical energy will be the more, the higher the wear of systems and equipment. Maintenance costs must also increase to keep the power system within regulatory requirements for high wear equipment. Outdated and worn-out equipment leads to an increase in energy losses, an increase in the cost of maintaining the state of working capacity and, as a result, financial losses. Reduction of electricity losses on worn-out equipment cannot be carried out instantly and radically due to the impossibility of the Ukrainian economy to upgrade power equipment in a short time. The authors propose to reduce financial losses by reducing the cost of maintaining existing equipment. And it is proposed to do this through the use of modern technologies, namely the use of UAVs for monitoring power equipment. It is proposed to pay attention to only one parameter, namely the uninterrupted operation of power facilities. Thus, for network companies monitoring the technical condition of lines and control of isolation means is the main type of monitoring. Density of failures of equipment operation is built in graphical form, where a normalized number of inspections is presented, based on reliability requirements. The number of inspections is calculated according to regulatory documents. The paper shows that the graph of the change in the probability of failure-free operation is not straight. Therefore, the frequency of inspections cannot use the frequency that is not related to the wear and tear of the equipment. And to maintain the level of reliability, it is necessary to increase the number of inspections to ensure the standard level of reliability. Therefore, the authors propose to reduce costs with an increased number of inspections using UAVs. The above economic calculations show the high economic efficiency of such a proposal.

Evaluation of the effectiveness of sliding redundancy of radioelectronic facilities

Objectives. The increased reliability of radioelectronic facilities can be achieved by the application of structural and load redundancy. Structural redundancy is achieved taking into account multiplicity of redundancy and the intensity of failures of elements of radioelectronic facilities, while load redundancy involves an easing of electrical, thermal, and mechanical operating modes of the elements. The choice of a redundancy method is determined according to reliability indicator requirements, which may often be contradictory. Therefore, the problem of how to effectively combine structural redundancy and load redundancy methods is very topical. In long-life radioelectronic facilities, for example, in satellite communication repeater systems, sliding redundancy is applied when limiting mass-dimensional parameters and consequently consumed energy. The aim of the work is to evaluate the efficiency of sliding redundancy according to various reliability indicators when altering redundancy multiplicity, reserve operating mode, element failure intensity, and switching device type.Methods. To describe the structure of a complex sliding redundancy system, a logical-probabilistic method is used, in which the dependence of the system reliability indicators on the reliability indicators of the elements is formulated as a logical function of operability. Graph-analytical methods are used to compare different variants of reliability logic schemes.Results. Mathematical models have been obtained to evaluate the effectiveness of sliding reservation. A comparative analysis of the efficiency of sliding redundancy with a loaded and unloaded reserve was carried out in terms failure-free operation probability, as well as gamma-percentage resource, failure rate when changing the fractional multiplicity of the redundancy, and element failure rate. The influence of the reliability of the switching device on the efficiency of the sliding redundancy is considered.Conclusions. Practical recommendations on the selection of the redundancy mode are presented according to different reliability indices and constructed mathematical models of the sliding redundancy efficiency coefficients. The correlation between the reliability indices of elements and the switching device whose reliability can be discounted, is determined. To increase the efficiency of sliding redundancy of radioelectronic facilities, it is necessary to combine multiplicity of redundancy and the operating mode of the reserve with approaches aimed at reducing the intensity of failure of elements.

Study of the regularity of wear influence on the service life of cutting elements of bulldozers’ working bodies

Our mathematical model describes the regularities of blade wear and takes into account the influence of different operating modes of a bulldozer when dealing with diverse soils that have different degrees of abrasiveness. When calculating the probability of failure-free operation of the bulldozer cutting elements (blades), which depends on the maximum load, it was found that the probability of failure-free operation at an operating time of 600 machine-hours is 0.7...0.75 – for soil category I; 0.5...0.55 – for soil category II; 0.3...0.35 – for soil category III. Comparison of failure-free operation probabilities has made it possible to establish that with an increase in soil density, failure-free operation probability drops by 30-40%, which suggests a significant impact of soil density on reliability of the bulldozer working equipment. In addition, this mathematical model of the total probability allows us to obtain a theoretical description of changes in failure-free operation probability of the bulldozer equipment during working processes, changes in the service life of a bulldozer blade, and taking into account the properties of the blade material. The service life of a bulldozer cutting element can be estimated by its wear, structural features of the material, geometric parameters (thickness in particular), and machine operating modes. It has been established that the regularity of changes in the service life, due to bulldozer blade wear, is exponential. The higher the soil category is, the lower the wear is, and hence the service life of a bulldozer working body. The dependence of the change in the blade service life on the time of its contact with soils of three categories was obtained as well. Thus, the maximum value of a blade service life at the beginning of operation on different soil categories was determined: 450 machine-hours – on soil category I; 350 machine-hours – on soil category II; 280 machine-hours – on soil category III.

PROBABILISTIC FORECASTING OF THE SERVICE LIFE OF REINFORCED CONCRETE AT ARCTIC OIL AND GAS FACILITIES, CONSIDERING DEFECTS AND DAMAGE

Currently, large fuel and energy companies are conducting intensive development of the Arctic territories of the Russian Federation by commissioning new capital construction facilities. At the same time, new formulations of modified concrete with improved performance properties are used. However, in extreme construction conditions, defects and damages can form, which affect the durability of structures. The paper presents the results of probabilistic modeling of the failure-free operation of reinforced concrete according to the criterion of the impact of carbon dioxide on concrete for the conditions of the new shift settlement Sabetta. Concretes with a water-cement ratio of 0.35 and 0.5 on slag-Portland cement were taken as calculated values. The results showed that without defects and damage, the period of normal operation generally corresponds to the design value of 50 and 100 years. If there are defects, the first local areas will appear in 40 years. Recommendations on repair of the considered defects and damages are given.

Mathematical Analysis of the Reliability of Modern Trolleybuses and Electric Buses

The rhythmic and stable operation of trolleybuses and autonomous trolleybuses or urban electric buses, depends to a large extent on the reliability of the equipment installed on the trolleybus. The actual operational reliability of trolleybus electrical equipment (EE) depends on its technical condition. Under the influence of external factors and specific operating modes, the technical condition of the equipment is continuously deteriorating, reliability indicators are decreasing, and the number of failures is increasing. Using the mathematical theory of reliability, probability theory and mathematical statistics, numerical methods of solving nonlinear and transcendental equations, this article defines the conditions of diagnostics depending on the intensity of failures and the given probability of failure-free operation of the equipment. Additionally, the inverse problem of determining the current reliability of electrical engineering systems depends on the terms of diagnostics and the intensity of failures being solved. As a result of the processing of statistical information on failures it is established that for the electrical equipment of a trolleybus, after a number of repair measures, the maximum density of failures occurs at a lower mileage, and the probability of failure-free operation can vary depending on the degree of wear of the equipment, i.e., on the number of previous failures. It is theoretically substantiated and experimentally confirmed that the reliability of trolleybus electrical equipment changes according to the exponential law of distribution of a random variable. It has been established that the real averaged diagnostic terms regulated by instructions are not optimal in most cases and differ several times from those defined in this paper. The dependence of switching equipment run-in on time has been clarified, which served as a prerequisite for specifying the inter-repair period for various types of trolleybus electrical equipment. A method of adjustment of the inter-repair time for the electrical equipment of trolleybuses is proposed.