Actual Technical Condition Research Articles

STATISTICAL MODELS OF PHYSIC-MECHANICAL CHARACTERISTICS OF ROADS IN THE AREA OF CULVERTS

Introduction. Increased technical requirements for roads, associated with increasing axial loads, the intensity and speed of vehicles, with the actual technical condition of the roads number, engineering structures, including culverts, activation of federal and regional services to bring the parameters of road surfaces to the world standards, all listed parameters pose the task in developing the mathematical modeling methods of physical-mechanical characteristics of soils in the culverts area. Therefore, such methods allow to reduce economic costs and time for carrying out experimental research of deformations based on the monitoring results of the soil roadbed and pavement.Materials and methods. The order of technical condition of the culverts’ research, pavement and physico-mechanical characteristics of soils, methods of experimental research were discussed in the article. Moreover, the approach to carrying out experimental works on penetration of pits in places of deformations and nearby was approved. Additionally, the evaluation of the soils condition on the roadbed and the annular space of the culverts was made.Results. The schemes of deformation and elasticity, density, humidity, consistency, plasticity number, fluidity, and physical properties of the soil are determined. The engineering-geological elements, mean values of density, humidity and compaction factor are established according to the research aim. Consequently, the values of the strain modules and the modulus of elasticity are calculated on the basis of compression and stamp tests.Discussion and conclusions. The dependence of the pavement on the physic-mechanical characteristics of the soil of the roadbed is proved. The correlation-regression analysis of soil characteristics is performed on the basis of experimental research. As a result, the regression equations are obtained in the annular space of culverts and at the distance of ± 30 m nearby. As could be proved, there are irregularities in the coverage of road clothes caused by drawdown in barrier locations. The physic-mechanical characteristics of the ground and strength characteristics are increased by culverts’ transfer on distance. The application of physic-mechanical characteristics of the soil together with experimental studies makes it possible to reduce labor costs, time and cost of testing.

Technology for Water Economy Monitoring of Technical State of Closed Drainage on Irrigation Systems

Technical state of closed drainage on irrigation systems owing to well-established, conditions for the country's economy development was without due attention beginning since the 90s of the 20th century and this was negatively reflected of their operational capability nowadays. Current survey procedures of closed drainage on irrigation systems are directed at evaluating, as a whole, serviceability of structure system elements for the further operation. When conducting survey a number of questions to the methods and ways to detect faults and defects as well as to forecast remaining life operational capability for the given period of time have been arisen. The objective to develop an automation technology for multifactor survey of closed drainage of irrigation systems is evaluating actual technical state of structural elements and the main equipment by the methods of non-destroying instrumental control, determination of remaining life operational capability of their elements as well as determination of safety deficit to evaluate possibilities of continuing operation above the fixed service life. The positive results of the above evaluation are the basis to prepare a structure for prolongation of its service life.

Analysis of change in the state of hydraulic drive of machines while in operation according to the diagnostic results

Technical diagnostics is a sphere of knowledge embracing theory, methods and means for defining the technical state of the objects. It is necessary for provision of security, functional reliability and efficiency of the technical object operation, as well as for reduction of the costs for its technical maintenance and reduction of the idle time losses caused by failures and premature shutdowns for maintenance. Therefore the objective of the paper is to analyze the change in the state of hydraulic drive of machines while in operation according to the diagnostic results. In order to achieve the set objective the authors used various experimental methods. The paper considers mutual influence of maintenance and technical diagnostics of hydrostatic drives of construction, track and some other mobile machines. It is shown that introduction of technical diagnostics allows transferring from the system of planned preventive repairs to the system of servicing the machines according to their actual technical state, which allows completely using the resource of a series of expensive aggregates. The authors described several main basic characteristics of change in the volume effectiveness of the hydraulic sets while in operation.

Development of a promising system for diagnosing the frogs of railroad switches using the transverse profile measurement method

We have developed a system for diagnosing the frogs of railroad switches, based on the application of modern microcontrollers of the type ESP with high technical characteristics and the simultaneous use of the information technology IoT (Internet of Things). The proposed system has advantages over mechanical systems in terms of the accuracy of data, their operational processing and submission to user in order to analyze technical condition of frogs at railroad switches. The results of measuring the transverse profile of frogs at railroad switches make it possible to take scientifically-substantiated decisions regarding the need for recovery repair of frogs by the method of surfacing and for control over gradual decrease in their carrying capacity, for establishing their actual technical condition and residual resource.We carried out experimental-theoretical research into longitudinal profile of frogs at railroad switches laid on the reinforced concrete bars. It was established as a result that after passing 50–65 million tons of cargo (that corresponds to the medium degree of wear) the trajectory takes the shape of a bump. We observe sharp hollows on the reinforced concrete base in the zone where a wheel rolls from a rail wing onto the core, characterized by significant total inclination. Subsequently, when the passed cargo increases, the number of sinusoidal irregularities grows. At wear close to maximal (80–95 million tons passed), the percentage of unfavorable trajectories (sinusoidal and hollows) grows; at low wear, they make up 49.8 %, at a wear of 5–6 mm and larger – 88.3 %. Sometimes there is a transformation of the sinusoidal irregularities into the wave-shaped ones.We have established characteristic motion trajectories of the center of mass of the wheel over the frog depending on the wear of rail wings and the core of a frog and the passed cargo. A mathematical model was constructed for predicting the wear of frog profile depending on the total weight of passed cargo.

ИНЖЕНЕРНЫЕ МЕТОДЫ ПРОГНОЗИРОВАНИЯ ОСТАТОЧНОГО РЕСУРСА ОБОРУДОВАНИЯ

One of the most important indicators of reliability of technical objects is their durability. Probabilistic and statistical methods used for group assessment of service life of marine equipment at the stage of its design are unsuitable for individual assessment of a residual resource during operation due to the great values of coefficients of the resource variation and significant discrepancies between the proposed and actual operation models. Improving the reliability of estimates can be achieved by controlling the actual operation and monitoring of diagnostic parameters which characterize degradation of the actual technical state of equipment. The article considers on specific examples the features of predictive extrapolation of time-series observations over diagnostic parameter and application of forecasting method based on the actual history of operational loadings. It is stated that the extrapolation method, in spite of such advantages as using a minimum number of controlled parameters and versatility, has a number of shortcomings that reduce its effectiveness in the evaluation of residual resource of multi-mode objects. To extend the use of extrapolative forecasting there have been proposed special methods of adjusting time series using the Euler method, linear and nonlinear regression models and the estimation approach of residual resource, which provides a preliminary study of physico-chemical deterioration of technical condition of equipment and subsequent measurement of the equivalent hours of the resource using results of the check operation and the hypotheses of linear summation of damage.

The impact of anthropogenic and external influences on the life cycle of a real estate object in Vietnam

The life cycle of real estate objects in Vietnam have been studied in the terms of negative anthropogenic and external impacts. It is shown in the paper that the reliability and longevity of the constructed objects are influenced in aggregate by all groups of the impact factors considered with the disclosure of the destructive processes leading to collapse of the buildings. It is explained that in order to ensure the safety of functioning of buildings erected in compliance with regulatory requirements at the stages of their construction and operation, it is necessary to conduct constant monitoring of their actual technical condition.

Neural network technique when distribution of vehicle component parts on the technological repair routes, taking into account their technical condition

Increase of repair efficiency is achieved due to the formation of centralized specialized production facilities which implement the vehicle component parts repair technique with the use of industrial technological processes to restore the technical state of the units and their components. In this case, the establishment of the expediency of sending the unit to repair, as well as the defining of volumes and nomenclature for necessary repair actions, should be performed at the stage of pre-repair diagnosis for each individual unit taking into account its actual technical condition. However, the effectiveness of pre-repair diagnosis using both deterministic and probabilistic methods of processing and analyzing the information obtained is significantly reduced by the presence of errors in the recognition of defects and the distribution of aggregates in accordance with the repair work variety preformed at the repair enterprise. Using promising cognitive technology based on neural networks it is possible to completely avoid the losses associated with the repetition of repair work. Therefore, the formation of scientific and methodological bases for the development, training and practical application of artificial neural networks in the subsystems of the pre-repair diagnosis of the repair fund of automobile vehicle omponent parts is an important and urgent task. The paper presents the results of analytical studies and a number of original techniques for the formation of scientific and methodological foundations for the development, training and practical application of artificial neural networks in the process of diagnosis the car vehicle component parts and special oil and gas equipment entering the centralized repair according to their technical condition

Method of assessing the influence of the moisture content in the braking fluid on the braking system actuation efficiency

Abstract The paper deals with assessing the influence of the braking fluid composition on the time of braking system actuation. It is justified that this factor should be taken into account in expert investigations of road accidents. The idea behind the research deals with putting forward proposals for improving the method for reconstructing road accidents by taking into account the braking fluid composition which can change during operation, resulting in increasing the time of brake drive actuation and in increasing the stopping distance of a vehicle equipped with a hydraulic braking system. The method of road accident reconstruction by adjusting standard (reference) values of braking parameters with consideration for properties of the braking fluid, affecting the time of deceleration rising up to its maximum and braking time with respect to steady deceleration, is reviewed. Experiments established the influence of the boiling temperature of the braking fluid and the moisture content on the total time of braking system actuation. A coefficient taking into account the influence of these factors on the estimated braking time and stopping distance of a vehicle is proposed and scientifically justified. The value of the paper lies in method application by automobile technical experts for the purposes of improving objectivity of expert evaluation results. The suggested refinements to the method allow improving and expanding the evidence base in road accident reconstruction in terms of the technical possibility to prevent the road accident, related to evaluation of the actual technical condition (as of the moment of the road accident) of the braking system equipped with a hydraulic drive.

EXPANSION OF OBJECTIVES OF THE PRACTICAL APPLICATION OF TECHNICAL AUDIT AT RAILWAY TRANSPORT ENTERPRISES

Purpose. The work is aimed to study, compare and summarize information on the current state and peculiarities of conducting technical audit in various branches of business in order to obtain the possibility of developing proposals for expanding the objectives of this procedure in railway enterprises. Methodology. In the course of the research there were used the methods of analysis and synthesis to study the content and basic provisions of scientific publications, normative legal acts of Ukraine, and other data on conducting technical audit in the field of industry, construction, gas extraction, electricity, marine and rail transport, followed by their comparison and generalization. Findings. Taking into account the positive experience of the audit carrying out in other sectors the article expands the goals of practical application of technical audit in railway transport enterprises. This envisages assessment of the current technical condition and the residual life of exploited vehicles and equipment of PJSC "Ukrzaliznytsia". As a result, there is an opportunity to detect and activate the reserves for improving the efficiency of railway transport enterprises, estimating and forecasting the costs for repair cycles and modernization, as well as for increasing the train safety level and improving investment attractiveness of the industry. Originality. The obtained results make it possible to broaden the concept of "technical audit" in railway transport, to define the purpose of its carrying out and the list of tasks. Application of the extended technical audit will provide an opportunity to receive objective information on the actual technical condition of the objects of the railway infrastructure, means of transport and equipment, and to use it for the formation of development programs as individual enterprises and the railway as a whole. Practical value. Expanding the goals of practical application of the technical audit at railway enterprises will increase the revenue part by identifying unused reserves, modernizing and obtaining investment, as well as reducing the expenditure part by minimizing the costs of eliminating the consequences of transport events, which is the cause of untimely identified technical risks.

MODERN METHODS AND MEANS OF ENSURING SAFE EXPLOITATION OF OIL TRUNK PIPELINES

High requirements apply to safe exploitation of oil trunk pipelines. Safe exploitation of oil trunk pipelines significantly mentions not only system of oil transportation, but also others adjacent systems. So, for example, safety inhibition active oil trunk pipelines owing to his damage may cause the stop of oil pumping from oil extraction spot to oil refining spot with violation of normal operating modes manufacturing plants of recovering and refining oil. Acceptance of evidence-based technical and technology solutions in design stages, high-quality building and strict observance of rules of technical operation ensure safety of operation on a production object. Properties of metal of pipes and the equipment of the main oil pipelines, their intense deformed state, the environment and properties of the pumped-over oil form parameters of safe operation of objects. Increase in level of mechanical tension in a wall of pipes and the equipment, change of tension in size and the sign, increase in frequency of these changes negatively influence safety of operation of the oil pipeline. Corrosive attack of the pumped-over product and the environment to metal of pipes and the equipment and also power impact of the environment on them reduce safety at operation of a construction. During long operation of pipelines there is a gradual deterioration in metal properties of pipes and the equipment and also accumulation of the defects leading to decrease in their safety. Safety of pipelines in the course of their operation can be reached by renovation, reconstruction, periodic determination of the actual technical condition and timely carrying out repair. Carrying out repair work is the most widely used way of safety during operation of the main oil pipelines. Repair of the main oil pipeline, owing to its design features and the rigid mode of operation, is rather difficult process demanding considerable expenses. There is a number of methods and means of repair of the main oil pipelines increasing industrial production safety. At the same time, the analysis of methods and means of repair shows need of their further improvement. The main directions of improvement of repair of pipes with use of couplings are given.

Identification of the operating parameters of a complex technical system important from the operational potential point of view

The most important processes which take place in a technical system are the operation and service processes. Knowing the actual technical state of the system, it is possible to make a decision whether the system can operate or should be serviced. The efficiency of the system operation and the possibility of the failure occurrence strongly depend on the relevancy of this decision. The technical state of the system is described by the system features affected by the time histories of its operational parameters. Unfortunately, the amount of the operational parameters can be significant. Therefore, it becomes purposeful to identify the operational parameters significant from the system technical state evaluation point of view. In the article, the universal method of the significant operational parameters identification and the research carried out in a real industrial system to verify its correctness and the accuracy are presented.

Diagnostics of the Technical State of Bearings of Mining Machines Base Assemblies

The article reviews the methods of technical diagnostics of equipment used during maintenance of mining machines in accordance with their actual technical state, and considers the basics of vibration parameters measuring. The classification of existing methods for diagnosing the technical condition of rolling bearings is given. The advantages and disadvantages of these methods are considered. The main defects of rolling bearings arising during manufacturing, transportation, storage, and operation are considered.

Intellectual technologies in the problems of thermal power engineering control: formalization of fuzzy information processing results using the artificial intelligence methodology

Exploitation conditions of power stations in variable modes and related changes of their technical state actualized problems of creating models for decision-making and state recognition basing on diagnostics using the fuzzy logic for identification their state and managing recovering processes. There is no unified methodological approach for obtaining the relevant information is a case of fuzziness and inhomogeneity of the raw information about the equipment state. The existing methods for extracting knowledge are usually unable to provide the correspondence between of the aggregates model parameters and the actual object state. The switchover of the power engineering from the preventive repair to the one, which is implemented according to the actual technical state, increased the responsibility of those who estimate the volume and the duration of the work. It may lead to inadequacy of the diagnostics and the decision-making models if corresponding methodological preparations do not take fuzziness into account, because the nature of the state information is of this kind. In this paper, we introduce a new model which formalizes the equipment state using not only exact information, but fuzzy as well. This model is more adequate to the actual state, than traditional analogs, and may be used in order to increase the efficiency and the service period of the power installations.

Development of a mathematical model of the generalized diagnostic indicato on the basis of full factorial experiment

Purpose. The aim of this work is to develop a mathematical model of the generalized diagnostic indicator of the technical state of traction substations electrical equipment. Methodology. The main tenets of the experiment planning theory, methods of structural-functional and multi-factor analysis, methods of mathematical and numerical modeling have been used to solve the set tasks. Results. To obtain the mathematical model of the generalized diagnostic indicator, a full factorial experiment for DC circuit breaker have been conducted. The plan of the experiment and factors affecting the change of the unit technical condition have been selected. The regression equation in variables coded values and the polynomial mathematical model of the generalized diagnostic indicator of the circuit breaker technical condition have been obtained. On the basis of regression equation analysis the character of influence of circuit breaker diagnostic indicators values on generalized diagnostic indicator changes has been defined. As a result of repeated performances of the full factorial experiment the mathematical models for other types of traction substations power equipment have been obtained. Originality. An improved theoretical approach to the construction of generalized diagnostic indicators mathematical models for main types of traction substations electric equipment with using the methods of experiments planning theory has been suggested. Practical value. The obtained polynomial mathematical models of the generalized diagnostic indicator D can be used for constructing the automated system of monitoring and forecasting of the traction substations equipment technical condition, which allows improving the performance of processing the diagnostic information and ensuring the accuracy of the diagnosis. Analysing and forecasting the electrical equipment technical condition with the using of mathematical models of generalized diagnostic indicator changes process allows constructing the optimal strategy of maintenance and repair based on the actual technical condition of the electrical equipment. This will reduce material and financial costs of maintenance and repair work as well as the equipment downtime caused by planned inspections and repair improving reliability and uptime of electrical equipment.

RELIABILITY FUNCTIONS OF ELECTROMECHANICAL POWER STEERING

For the English abstract and full text of the article please see the attached PDF-File (English version follows Russian version).ABSTRACT The vast majority of new cars are equipped with electromechanical power steering (EPS) because of their clear advantages compared to hydraulic and pneumatic devices. At the same time, the question of the technical operation of the unit has not yet been fully studied, the combination of electronic and mechanical systems in which does not allow the full use of existing methods and means of monitoring operability of a vehicle, its actual technical condition. In this regard, development of standards for control over a technical state on the basis of diagnostic information, systematization of scientific achievements in this field, the problems of increasing reliability of EPS in operation are particularly relevant. The results of the conducted research will help in creation of a method for controlling reliability of the unit. (To be continued in the next issue). Keywords: car, steering, electromechanical amplifier, technical state control, reliability, operation.

MATHEMATICAL MODEL'S CHOICE REASONING AND ITS IMPLEMENTATION FOR THE EVALUATION OF THE STRENGTH OF TECHNOLOGICAL VESSELS

In connection with the global increase in the intensity of use of working equipment related to high-risk facilities and the expiry of the service life limit, the question arises of determining the actual technical condition and forecasting the residual resource. From the analysis of the approaches to determining the technical state and on the analysis of regulatory documents, it becomes clear that the regulated methods of assessing the technical state are obsolete, such that they do not ensure the reliability of the obtained control results. A new technique for determining the actual technical state through monitoring the level of stresses in the body of high-risk objects is proposed. The new technique takes into account additional physical and mechanical parameters that affect the stress-strain state, and have not yet been used. In other words, the technique of multivariable control of stress determination was proposed. Mathematical models of the process of deformation and stress for cylindrical vessels with a spherical and conic dome operating under the action of high pressure are proposed.

Definition defects of transformer equipment using frequency diagnostic parameters

The purpose of the article is to investigate the damageability of power equipment of electric power systems, methodsand means of their diagnostics.The article presents the results of studies of the damageability of power transformers, which indicate that a considerable partof such damages are defects in magnetic circuits and windings. Also, studies Defects power equipment of power systems in mostcases is from 1 to 3 years of operation and one after 25 years. These are such damages as radial and axial deformations of windings,sliding of coils of windings, results of "fire in steel", etc. It is also shown that among the most frequently damaged nodes and parts ofa transformer, there are windings and magnets. This indicates that monitoring of the current and the idling power of the transformer,the active insulation resistance of the windings, the short-circuit resistance and other diagnostic parameters stipulated in theregulatory and passport documentation, using diagnostic tools available for enterprises operating transformers, Some defects ofthese parts and assemblies, especially at an early stage of their development. Determined that the defects associated with defects inthe windings and magnetic deterioration best detected by comparing the frequency characteristics. Attention is also drawn to the factthat sometimes effective use of modern diagnostic equipment is limited by the absence of domestic normative documentation thatallows to interpret the results of diagnosing transformers with new methods reasonably, to assess the actual technical condition thatis necessary for its account during operation, repair planning, replacement and disposal

Modification Research of Pavement Deflection Representative Value Formula Based on Wavelet Transform

Because the measured deflection of expressway asphalt pavement does not obey the normal distribution, the calculation formula of deflection representative value can’t be used. In order to solve it, in the premise of keeping original characteristics of the measured deflection data, by using the two times standard deviation method, the specific data of the original measured deflection data were eliminated and then furthermore the noise of the deflection data was managed through wavelet transform. The normal distribution ratio of the measured deflection data of asphalt pavement were increased from 20.0% to 86.7%, the requirement of the original formula of deflection representative value was meet, so according to the method, the original formula of the deflection representative value can be modified. Engineering Practice shows that the revised deflection representative value calculation formula that was applied to evaluate the pavement structural strength was suitable. Its evaluation result can reflect the actual technical condition of roads.

Operational control and diagnostics of the equipment by the parameters of the electric drive power supply by the example of deep well pump units

Currently, the vast majority of Russian oil wells use oil well pumping units (OPU), equipped with a mechanical drive – a balancing pumping unit. The significant lifetime of balancing pumping units used in oil fields of Russia amounts to full or close to full resource generation and to a high accident rate of the mechanical drive rod of OPU. Reduced material costs for operation and maintenance of OPU may be provided by the rejection of the system of preventive maintenance and service during the transition to the actual technical condition. The article analyzes the statistics of the most frequent crash balancing pumping units of OPU and their causes. The prospect of applying the method of instrument control parameters is proved, and the technical condition of the OPU is assessed based on the analysis of the magnitude and the nature of changes in load drive motors, determined by the recording of the instantaneous values of power consumption. The authors consider the construction and operation of the programmable controller ‘AKD-SK’ manufactured by JSC R&D company ‘ROS’ (Perm). Fundamentals of vattmetrogramm analysis of OPU drive motors are stated, and the character of displaying key defects of submersible pumps and balanced beam unit is described.

Применение методологии искусственного интеллекта для формализации результатов обработки нечеткой информации

One of the distinctive features pertinent to the present-day conditions under which the power plant equipment operate is the necessity to run it in variable modes, as a result of which certain changes occur in the equipment technical state with time. These factors have generated the need of solving, on a priority basis, a number of unresolved matters concerned with creating models for decision-making and state recognition proceeding from power plant diagnostics with the use of fuzzy information for identifying the equipment state and managing the equipment recovering processes. It should be noted, however, that there is no unified methodological approach to obtaining the relevant information for diagnostic purposes in solving such problems under the conditions of fuzziness and inhomogeneity of initial information about the actual equipment state and its residual life. As a result, the existing methods for shaping data and knowledge in performing an analysis of data and in making managerial decisions are not identified and are not interconnected with their mathematical models. In addition, they are aimed at solving separate tasks and are not always able to ensure that the equipment set model’s parameters are consistent with the actual state of the facility in question. At the same time, the shift that was done in the power industry from the policy of planned and preventive repairs to the policy of repairs according to the actual technical state has resulted in that a higher responsibility has to be undertaken by those who make decisions in determining the repair scope and timeframes, and, accordingly, more stringent requirements are imposed on the quality of diagnostic models. As a consequence of its having been made without doing proper methodical background work, such a shift has lead a situation in which the diagnostic and the decision-making models turned to be inadequate due to the use of information about the equipment state that contains uncertainties. At the same time, recent years have seen a drastically grown interest in various aspects of the intellectual management problem, in particular, the intellectual management by technologies according to a hybrid principle. One of the main areas involves the use of techniques developed within the framework of fuzzy systems and cognitive neural sciences: fuzzy sets, fuzzy logic, fuzzy modeling and management, semantic memory organization, fuzzy mathematics, artificial neural networks, pattern recognition, data processing by human neurons and brain, human consciousness, mind, memory, and artificial life. The article presents the results from extending the range of practical applications of the fuzzy and hybrid system techniques as applied to the technologies of estimating the state of complex technical systems (including power systems), especially under the conditions of data processing and using cognitive neural sciences.