Changes In Technical Condition Research Articles

Development of a model of the process of development of manufacturing defects in automation means

In automated process control systems, automation equipment (sensors, converters, amplifiers, etc.) with technical defects arising during their manufacture, which are one of the main causes of failures, is widely used. The paper establishes the possibility of using the laws of nonequilibrium thermodynamics as the basis for determining the relationship between the controlled parameters of automation equipment and the parameters of the displayed medium, which made it possible to build a deterministic model of the development of production defects and, ultimately, determine the directions for changing and adjusting the technological processes of production of automation equipment. A method has been developed for implementing a guaranteed forecast of changes in the parameters of automation equipment based on solving the evolution equation using optimal filtering algorithms, which is the subject of research. The purpose of the work is to improve the quality and reliability of automation equipment by improving the monitoring of defects arising in the production of instruments, functional units and sensors of automation equipment. The article solves the following problems: analysis of existing approaches to the problem of manufacturing defects and methods for their detection and setting a research task; modeling of the process of development of production defects causing changes in the technical condition of automation equipment; development of a decision-making method based on guaranteed prediction of the technical state of automation equipment. The methodology of work is based on the methods of thermodynamic description of the kinetics of processes (when developing a model of the process of development of production defects that cause a change in technical condition) and methods of assessment and forecasting based on optimal filtering algorithms (when developing a decision-making method based on guaranteed foresight of technical condition). The results of the work include a model of the process of development of manufacturing defects that cause a change in the technical condition of automation equipment, and a decision-making method based on a guaranteed forecast of the technical condition of automation equipment. Conclusions. The paper establishes the possibility of using the laws of nonequilibrium thermodynamics to determine the relationship between the controlled parameters of automation equipment and the displayed medium, and to build a deterministic thermodynamic model of the development of production defects. Disclosed is an equation of evolution of technical state of automation equipment based on a deterministic kinetic model of processes occurring in a multicomponent medium, and an observation model which takes into account errors caused by instability of external effects and measurement errors. Disclosed is a method of implementing a guaranteed forecast of change in parameters of automation equipment based on solving the evolution equation using optimal filtering algorithms, which are used to solve estimation and prediction problems.

Taking into account the random function of parameter deviation in predicting the reliability of equipment

In article the question on forecasting of reliability of the equipment is considered. The characteristics infl uencing change of technical condition and reliability of the car (system) are analysed. Infl uence of stochastic function on a deviation of the actual values of parameter of technical condition is considered and the solution on her account is proposed.

Vibration diagnostics of the main power plant of vessels: improvement and integration of methods

The study is devoted to the development of a comprehensive approach to vibration diagnostics of the main power plant of water transport vehicles. The method of automatic processing of narrowband spectra is being improved. The method of automatic adaptation of threshold values for timely detection of changes in technical condition against the background of natural monotonous changes in vibration parameters characteristic of ship conditions is being improved. In the course of the study, the peculiarities of the spectra of vibration signals of rotary equipment were formulated and their analysis was carried out from the point of view of evaluating the parameters of diagnostically significant components. Automatic systems of centralized control and management are traditionally used to assess the current performance of SEU on ships. Their main purpose is to assess the quality of the SEU performance of the specified operating modes. But these systems do not allow solving the task of early prediction of the loss of performance of the most loaded and failure-prone SEU elements - rotary machines, because the controlled parameters of technological processes are either inertial and do not change synchronously with the development of faults, or do not react to the development of a number of dangerous defects until the onset irreversible consequences. The method of automatic diagnostics was further developed based on the results of monitoring vibration parameters of various nature and the assessment of the diagnostic significance of their changes against the background of natural monotonous fluctuations

АНАЛИЗ СОВРЕМЕННЫХ МЕТОДОВ ДИАГНОСТИРОВАНИЯ ГАЗОПОРШНЕВЫХ АГРЕГАТОВ С СИНХРОННЫМИ ГЕНЕРАТОРАМИ НА ОБЪЕКТАХ ДОБЫЧИ НЕФТИ

Relevance One of the best available technologies for the utilization of associated petroleum gas and the generation of electrical energy is the use of gas piston units at oil and gas production enterprises. At the same time, limited funds for equipment repairs and unfavorable external conditions often force industrial enterprises to switch to a repair strategy based on technical condition. The type of organization of repairs based on the technical condition of the main power and electrical equipment can be used if the electric power industry entity has technical diagnostic tools and an automated system for monitoring the technical condition of the main equipment, which is a hardware and software complex that ensures the process of remote monitoring and control of the condition of the equipment and (or) object (operating equipment), its diagnosis and prediction of changes in technical condition based on collected data (historical data on the condition of the equipment) and operational data received from data collection systems installed on the equipment. At the same time, when organizing repairs based on the technical condition of equipment, the list and scope of repair measures should be determined based on the results of the performed monitoring and diagnosis of its technical condition. Thus, diagnostics and assessment of the technical condition, the emergency shutdown of which can cause the shutdown of the oil-producing well stock, is an important task, the solution of which helps to reduce operating costs, increase reliability, reduce the number of emergencies, reduce costs and losses of working time associated with unscheduled repairs of equipment and technological problems. Aim of research The aime of the study is to analyze the current methods for diagnosing gas piston units, as well as promising technologies in the field of diagnostics. Methods Analytical review of scientific literature. Results The article analyzes methods for technical diagnostics of gas piston units with synchronous alternating current generators, taking into account their advantages and disadvantages. Promising directions for the development of diagnostic systems of electrical machines are considered.

ІНТЕГРАЛЬНА ІНФОРМАЦІЙНО-ОБЧИСЛЮВАЛЬНА СИСТЕМА, ЩО ЗАБЕЗПЕЧУЄ ТЕХНІЧНЕ ОБСЛУГОВУВАННЯ ЗА СТАНОМ СИЛОВИХ ГАЗОТУРБІННИХ УСТАНОВОК

The effectiveness of the chosen maintenance strategy is determined by the completeness of information about the current technical condition of the facility. The real current state of a dynamic object should specify the list and scope of preventive and remedial work for each specific maintenance object. Existing strategies and programs according to the technical condition of dynamic objects are conditionally divided into three groups: with control over the level of reliability of the operating object; with control of the parameters of the object of operation; hybrid. Power gas turbine plants are objects of operation with high functional significance. They have an insufficient degree of redundancy, as well as a low level of operational manufacturability. Therefore, it is advisable for them to apply a maintenance strategy as per the parameter control. The article proposes general principles on the basis of which an integral information-computing system for processing parameters can be built. This system is the main element of the automated control system for the technical condition of the gas turbine power plant. Synthesized adaptive system for dynamic control of parameters characterizing the current technical state of a gas turbine power plant. Closing the control loop of the technical condition of the object with negative feedback allows you to switch from the strategy of its maintenance according to the operating time to the maintenance strategy according to the state with the control of parameters. The integrated information-computing system should solve two main tasks: a reliable assessment of the current technical state of a dynamic object and prediction of a pre-failure state in the medium and long term. The main condition for organizing the maintenance of dynamic objects according to the state with the control of parameters is the possibility of continuous monitoring of the parameters characterizing the current technical state. The choice of such parameters is ambiguous, which is due to both the specific features of dynamic object and diverse nature of relationship between faults and controlled parameters. The requirements for the determining parameters are of a general nature: the parameters must have acceptable accuracy and stability of readings over time; have the greatest diagnostic value among other parameters; not depend on changes in external operating conditions and modes of operation; based on standard measurements. The system of continuous monitoring of parameters characterizing technical state of a dynamic object must be adaptive. It should change in accordance with the change in technical condition of the gas turbine power plant. The use of a set of parameters of its dynamic linear model as characteristic of the current technical state of an object is justified for a wide class of objects. The control system of such objects operates in the stabilization mode, therefore, the adaptive system of continuous monitoring synthesized on the basis of this model provides the possibility of assessing the current technical state of the gas turbine power plant and makes it possible to predict its technical state. At the same time, the adaptation of the parameters of the linear dynamic model of the object to the new technical condition of the gas turbine plant should be carried out with the least interference in the normal operation of the plant.

Automatic Homogenization of Time Series: How to Use Metadata?

Long time series of observed climate data are often affected by changes in the technical conditions of the observations, which cause non-climatic biases, so-called inhomogeneities. Such inhomogeneities can be removed, at least partly, by the spatial comparison and statistical analysis of the data, and by the use of documented information about the historical changes in technical conditions, so-called metadata. Large datasets need the use of automatic or semiautomatic homogenization methods, but the effective use of non-quantitative metadata information within automatic procedures is not straightforward. The traditional approach suggests that a piece of metadata can be considered in statistical homogenizations only when the statistical analysis indicates a higher than threshold probability of inhomogeneity occurrence at or around the date of the metadata information. In this study, a new approach is presented, which suggests that the final inhomogeneity corrections should be done by the ANOVA correction model, and all the metadata dates likely indicating inhomogeneities according to the content of the metadata should be included in that correction step. A large synthetic temperature benchmark dataset has been created and used to test the performance of the ACMANT homogenization method both with traditional metadata use and with the suggested new method. The results show that while the traditional metadata use provides only 1–4% error reduction in comparison with the residual errors obtained by the homogenization without metadata, this ratio reaches 8–15% in the new, permissive use of metadata. The usefulness of metadata depends on the test dataset properties and homogenization method, these aspects are examined and discussed.

Особенности работы верхнего строения пути в условиях продолжительного зимнего периода

Purpose: To determine legitimacies of changes in technical state of railway permanent way in the areas with harsh climate conditions with the purpose to design track maintenance system in the Arctic conditions. Methods: During the study, an analysis of main indicators of permanent way (upper construction) technical condition was carried out such as the way’s element defectiveness (rails, fastenings, sleepers, ballast pollution) and faults of geometric parameter norms of rail track (widenings and narrowings, alignment by a level, sags, subsidences, position in a plan). Data analysis was carried out in accordance with specially created model of the dependence of changes in the parameters of permanent way technical condition from a workload tonnage inclusive of annual periods. Results: Based on the observations, the change in track maintenance costs for the lines located in continuous winter conditions was determined. These are costs, related to railway track faults and defectiveness of track superstructure (permanent way) elements. Practical importance: The results of the study ‘re intended for the work planning system development on track maintenance and repairs in harsh climate conditions.

The Use of Multicriteria Inference Method to Identify and Classify Selected Combustion Engine Malfunctions Based on Vehicle Structure Vibrations.

Internal combustion engines are among the most commonly used propulsion units for drive systems in various industries such as land transportation, maritime transportation, and power generation. Their operation involves a continuous change of technical condition as a result of not only the combustion process but also their operation under conditions of variable load or ambient impact. It is therefore important to monitor the technical condition of internal combustion engines to ensure high performance and reliability over their lifetime. The article presents the test results obtained from incorrect operation of an internal combustion engine as a result of forced failures of the ignition and injection system. On this basis, a multicriteria comparison of the signal analysis of engine block vibrations was made, after the transformation of the signal from the time domain to the frequency domain, by using the induction technique obtained from the operation of decision tree algorithms. For this purpose, the amplitude spectrum in the frequency domain, scaled to absolute values of discretization for which teaching and testing data tables were created for successive harmonics, was determined for the engine block vibration signal being tested. On the basis of the developed algorithm using decision trees, a multicriteria data table was analyzed for which a compatibility path for the analyzed engine block vibration signal is created. In this way, it is confirmed with a specified degree of effectiveness, depending on the point of operation of the engine resulting from its crankshaft speed, that there is a possibility of detecting a preset ignition or injection system malfunction in the technical condition of the internal combustion engine with a probability up to about 72%.

Change of Technical Condition and Productivity of Grain Harvesters Depending on Term of Operation

The regularities of change of technical condition of combine harvester Slavutich KZC-9F depending on service life are determined. It is determined that after the second year of operation, the readiness factors decrease in one season by 0.044 or 5.2%, and the recovery factors increase, respectively, their productivity decreases.Within the normative costs for overhaul repairs of combines and maintenance of their operability during the harvest after the second season of operation, there is an annual decrease in the readiness factor by 0.036.Analysis of rate of change of indicator of selective assessment of the readiness factor allows us to conclude that the service life of the main units, systems, mechanisms of combines is exhausted by the service life of five to six years and a total output of 1200-1400 hours with an average output for the season of 200-280 hours.If the duration of downtime to eliminate failures after the third year of operation changes to a maximum of 22%, the recovery rate increases by 35%.The productivity of the combine harvesters Slavutich KZC-9F increases with increasing service life due to a decrease in the readiness factor. A decrease in the readiness factor by 0.01 causes a decrease in the productivity of the combine by 21.2 tons/season.

The Irregularity Change of the Technical State`s Elements of the Vehicle: form Submission

Analyzed the use of the term «irregularity changes of technical condition of element’s vehicle» to certain stages of the operational cycle. Specific examples and quantitative assessment of irregularity changes the structural parameters for the elements, working independently, and interacting in the units or systems of the vehicle.

Revealing the patterns of change in the technical condition of refractory elements in thermal units during operation

Operating conditions of thermal units for processing raw materials predetermine defects in refractory elements resulting in their gradual accumulation, which leads to a change in technical condition. A large number of defects, their development, and the achievement of critical values lead to difficulties in modeling the physical processes of changing the technical condition of refractory elements.This study has investigated the mechanism of the occurrence, development, and accumulation of defects in refractory elements, as well as the processes of cumulative accumulation of damages; a probability model of their degradation has been constructed. The model was built using Markov chains; it describes the sequences of change in the states of refractory element damage and the probability of transitions between these states. Based on the statistical data about a change in the state of damage, the model makes it possible to assess the probability of a defect reaching the critical condition following the predefined number of load cycles. A special feature of the model is the possibility of its application to individual defects, as well as to refractory elements on which defects occur and develop, as well as to assemblies where such refractory elements are installed.The main patterns of change in the technical condition of refractory elements of coke ovens have been established: the distribution of cracks of a certain length according to the number of coke oven output cycles; the probability of the occurrence of a crack of a critical length at a certain point during operation; the dependence of the probability of a refractory element failure on the predefined number of coke oven output cycles.Based on the modeling results, it has been proposed, in order to prevent the degradation of refractory elements, to strengthen the structure of the surface layer of the refractory element by cold gas-dynamic spraying, to arrange laying elements that would stop the evolution of defects, and to make up schedules of hot repairs based on the time when the defects may reach critical values, determined during modeling

Technological features of formation of functionally oriented coatings of marine diesel engine parts

The article discusses the formation of functionally oriented coatings of marine diesel engine parts, general approach to the synthesis of the basic technological process, and technological features when apply-ing multilayer coatings with variable properties. The formation of coverage is associated with the provision of the required resource for marine diesels and their elements. The choice of the criterion of the limiting state is determined by the features of the operational function acting on the diesel element. Classifications of parts of marine diesel engines and processes causing a change in technical condition are given. The justified establishment of the criterion of the limiting state makes it possible to solve the problem of ensuring an equal specified life or a multiple one of the former one.

Metoda szacowania trwałości lotniczych napędów hydraulicznych

Throughout previous practice, estimating the life of aviation hydraulic drive assemblies has been utilizing a variant, which requires conducting long-lasting studies of the drive assemblies until they move to the unfitness state. Such studies, which enable estimating life a posteriori, are costly and long-lasting. Hence the need to look for new strategies for estimating life. The article presents a method of estimating the durability of a hydraulic drive assembly based on the control of its change in technical condition. Inspection of the technical condition enables timely detection of the condition before the emergency hydraulic assembly. The novelty of the method is to use, to detect the condition before the emergency team, the principle of determining the pre-emptive control parameter tolerance. Pre-emptive tolerances are a set of control parameter values between threshold levels and pre-emergency (allowable) levels. The intensity of depletion of durability (intensity of aging, wear) is random. The paper presents a stochastic description of the control parameter change and the resulting empirical relationships between the control parameter verification time probability density (verification periodicity) and the control parameter value change probability density. The inter-relations between these two functions were described. It also presents empirical relationships enabling the determination of the permissible value for the control parameters and the periodicity of the control parameter checks after exceeding the limit value. An example of estimating the life of a hydraulic piston pump on-board an aircraft operated in the Polish Air Forces was shown. The permissible values and the time for the first control parameter verification after exceeding the limit value were determined for selected control parameters of the hydraulic pump. The proposed method binds life (fitness time) with the physical wear mechanisms concerning the assemblies. It can be applied in work aimed at determining the resource life of technical equipment. Furthermore, it enables utilizing technical equipment according to a technical state strategy with monitoring the parameters.

Modeling of technologies in the vehicle maintenance on the basis of fuel consumption

Problem statement. A modern vehicle like any mechanical vehicle is a rather complex system consisting of a large number of subsystems, power units, units, elements (parts). Each element of a vehicle is manufactured with certain tolerances on the composition of the material, on its physical, chemical, mechanical, thermal, electrical properties, on shape and size. During the operation of a vehicle, it interacts with the environment (including transported goods or people), and its elements interact with each other. This interaction causes a load of parts, their mutual displacements, friction, heating, chemical transformations. As a result, during the operation the properties (parameters) of these elements change. They are hardness, surface roughness, size, relative position, gap, etc. A partial solution to the problems presented may be the search for methods for assessing the technical condition of a vehicle by a generalized criterion that is quite sensitive to changes in technical condition. One of these criteria may be fuel consumption in liters per 100 kilometers. Purpose. To explore the possibilities of using the fuel consumption indicator as a criterion for assessing the technical condition of vehicle and generalize the technology of maintenance and repair of motor vehicle and obtain a given technical solution. Conclusion. The possibility of using the fuel consumption indicator as a criterion for assessing the technical condition of vehicles by the example of Volkswagen Touran 1.9 TDI during operation is investigated. A clear dependence of fuel consumption on the life of the car is established, which means that it depends on its frequency and the quality of the maintenance and repair system. The technology of maintenance and repair of vehicles and obtaining a given technical solution is generalized. The process of creating a model of technology for maintenance and repair of vehicle is implemented on the basis of an iterative approach (reiteration) with the ability to clarify their features.

Assessment of Strength and Useful Life of Hydraulic Units with Partial Replacement of Equipment

Modernization and comprehensive reconstruction of hydraulic units that have exhausted their design service life are among the most important directions in the development of hydraulic power engineering over the next 10 – 20 years. Assessment of the remaining service life of the hydraulic unit as a whole and of individual assemblies that do not have to be replaced is of importance for arriving at a management decision on the need to replace elements and create a list of individual assemblies that do not have to be replaced. The existing industry regulatory base does not define the issues related to prediction of changes in technical state and individual assessment of the remaining service life of a hydraulic unit that has exhausted a lengthy service life under the conditions of actual operation in a hydroelectric power plant. This prevents us from standardizing the process of evaluating the strength and life of equipment following modernization of a unit of equipment or partial replacement of its assemblies and elements.

Experience of diagnostics of engineering structures by the method of small impacts

The problems of diagnostics of engineering structures during their service life are considered. As one of the promising methods, the method of vibration diagnostics for changing dynamic parameters (natural frequencies and decrements of oscillations, amplitudes and forms of oscillations) was chosen. The results of various studies in the field of vibration diagnostics of bridge structures are analyzed. The results of the study of the influence of various damages on the dynamic parameters of structures using finite element models are presented. Summarized data of long-term studies of the Siberian transport University to evaluate the technical state of structures based on measurement of natural oscillation frequency. The limitation of the method of vibration diagnostics for lower forms of vibration is associated with low sensitivity and significant influence of various factors on the results. However, in some cases, vibration diagnostics of structures under excitation of oscillations by small pulse effects can be effective. Examples of vibrodiagnostics of the state of structures are given. Vibrodiagnostics is particularly relevant in the study of the actual dynamic work of pedestrian bridges. Regular fixation of «digital dynamic portraits» allows you to track changes in technical condition. It is advisable to use methods of vibration diagnostics and in assessing the effectiveness of strengthening structures. In conclusion, it is noted that using the methods considered, it is possible to organize a system of periodic or continuous automated monitoring of the technical condition of bridges. This is especially important to prevent sudden failures of technically complex and unique structures, as well as in the case of serious damage to the load-bearing structures.

Ensuring the operational reliability of the tractor fleet

One of the major problems facing the engineering and technical service of agricultural enterprises is to figure out the volume of repair and maintenance impacts to ensure the optimal operation of the tractor fleet in conditions of limited financial resources. The study introduces individual reliability indicators of tractors, based on the analysis of the machine and tractor fleet in the Vologda region. The condition for the formation of rational and effective repair and maintenance impacts is the constant monitoring of reliability indicators of tractors and agricultural machinery, which allows not only identifying their individual characteristics, but also predicting changes in technical state. Studies have shown that different systems of tractors, in particular MTZ tractors, can differ by reliability actually n several times. The interrelation between the invested funds for repairs and the subsequent failure-free operation was found out. The increase of failure-free operation allows reducing the probability and the amount of downtimes in the busy farming season, thereby reducing the possible costs associated with losses due to downtime of machines, such as: violation of agro-technical terms, which is especially important for sowing and harvesting, being one of the factors of yield reduction. These studies laid the foundation for the method for determining the rational volume of repair and maintenance impacts, which consists in minimizing the total costs aimed at improving the failure-free operation of tractors. All this, along with using the up-to-date diagnostics tools, will increase the efficiency of preventive repair and maintenance impacts.

Approaches to increasing the efficiency of systems of technical diagnostics

The growing importance of systems of technical diagnostics as an integral element of complex technical systems, determine the need of developing an assessment methodology and improve the effectiveness of systems of technical diagnostics themselves. Generally assessment of the impact of systems of technical diagnostics on results of functioning of an object of diagnostics can be received by comparison of indexes of efficiency of an object of diagnostics without the system of diagnosing and with the system of diagnosing. In practice the cost efficiency of the systems of technical diagnostics and various indexes characterizing quality of technical diagnosing are usually calculated. In a general view, the "contribution" of the system of technical diagnostics to decrease in an accident risk and risk from operation of the object of diagnostics can be estimated on the basis of the functional, accounting the reduced cost of creation and functioning the system of technical diagnostics and the direct losses caused by risk of accident (refusal) of the system of technical diagnostics. The inefficiency of the system of technical diagnostics is, as a rule, caused by discrepancy of its parameters with the tasks solved by it; these tasks are: development of algorithms of diagnosing, forecasting of change of technical condition, development of methods and diagnostic devices. This made it possible to formulate some main directions and conditions for the formation of effective systems of technical diagnostics.

The Use of a Mathematical Model of Marine Diesel Engine in a Computer Program

Abstract The paper describes the application of the author’s mathematical model of gas-dynamic processes for a marine piston engine based on a computer program. The developed mathematical and numerical model is designed to conduct simulation diagnostics. Therefore, it is possible to carry out calculations for motors in different technical conditions and observing influence of changes in technical condition on selected parameters of its work. Simulation of changes in technical condition is carried out by modifying parameters of structure’s model object. The article contains a detailed description of each options of the computer program. From the main program window, user can select type of engine model (supercharging method, cylinder number, work order, stroke and piston diameter and a number of other parameters). Through a window of simulation of known and recognizable damages such as: change in fuel dose for each cylinder, change in intake and outlet valves, leakage of piston-ring-cylinder system, change of injector hole cross section. Final windows show results of calculations in form of mileage parameters of engine as a function of crank angle.

The method for increasing the efficiency of equipment’s maintenance in railway traction power supply systems

Purpose. To develop the method for increasing the efficiency of the equipment’s maintenance and repair system, ensuring necessary level of operational reliability of the equipment, safety and reliability of the electric equipment with minimal expenses on operation. Relevance. Aging of the power equipment in railway power supply systems sharply raised a need for assessment of its states and degree of risk for operation outside rated service life. In critical conditions of technological processes and operational modes of the railways it is necessary to increase the equipment’s operational reliability. The scheduled maintenance and repair system whose main technical and economic criterion is the minimum of equipment’s downtimes on the basis of a rigid regulation of repair cycles, in the conditions of market regulations in the field of repair in many cases does not provide the optimal decisions due to insufficient financing. The solution of this problem is possible by improvement of the maintenance and repair system. Under these conditions the main direction for supporting the operational reliability of power electric equipment on TS is a development of the modern methods based on individual supervision over real changes of technical condition of power equipment. Scientific novelty. In this article the authors proposed an integrated approach, on the basis of which can be developed the effective maintenance and repair system for traction power supply systems. Proposed approach allowed to react quickly to changes of service conditions on traction substations, to control the technical condition of power electric equipment under the conditions of uncertainty, to establish interrelation between quality of service and operational reliability of the equipment, to choose a service strategy on traction substations. Practical importance. The validity of the developed method was confirmed by the results of calculations and practically by choosing the optimal maintenance's option for transformer TDTN-25000/150-70 U1 (ТДТН-25000/150-70 У1) on traction power supply substation.