How to determine the remaining life of machine parts

Author(s):  
Vyacheslav I. Chernoivanov ◽  
Vyacheslav A. Denisov ◽  
Aleksey A. Solomashkin

The article presents three strategies for maintenance and repair of machines that control the pre-selected and justified parameters of the technical condition of the machine, as well as the costs of eliminating failures for these strategies and the possibility of reducing them. (Research purpose) The research purpose is to identify the most effective way to determine the residual life of machine parts. (Materials and methods) The article proposes a strategy for maintenance and repair of machines, in which a special place is occupied by ways of reducing the mechanical friction losses, increasing the efficiency of the machine and the service life of its parts. The article notes that in order to meet the service life, it is necessary to monitor their remaining life visually or using appropriate sensors. In order to determine the remaining resource in more accurately way, we suggested that it would be measured several times, preferably using different methods or devices. Authors designed a computer program that allows to estimate the remaining resource using an interval estimation of random values for a given probability of failure-free operation of the machine part. The plunger pairs of a high-pressure fuel pump were chosen as the object of research. As a diagnostic parameter that characterizes the technical condition of the pump, its starting cycle feed was used, the value of which was determined on different stands. (Results and discussion) Article presents the values of the average resources of the plunger pairs, their dispersion around the corresponding average values, and calculated their average residual resource as an interval estimate for a given probability of failure-free operation. (Conclusions) The research results have shown a possibility of using the residual resource as the basis of the proposed strategy for maintenance and repair of machines based on minimizing the residual resource of their parts. The most important unsolved task for this strategy remains the selection and justification of primary diagnostic sensors for assessing the residual life of machine parts.

Author(s):  
Aleksey S. Dorokhov ◽  
Aleksandr V. Denisov ◽  
Aleksey A. Solomashkin ◽  
Valeriy S. Gerasimov

Modern machines are subject to progressive wear that occurs at different rates, which leads to unpredictable failures that reduce the reliability and durability of machines. The strategy of maintenance and repair is aimed at eliminating these problems. (Research purpose) The research purpose is in analyzing the basic principles of the strategy of maintenance and repair of agricultural machinery in order to ensure control of the technical condition of machine parts. (Materials and methods) When resource diagnostics is used, , the allowable value of the parameter is set in advance for a part . This value is the tolerance that corresponds to a certain wear rate of the part. The tolerance is set based on the condition that if the current value of the controlled resource parameter during the next diagnosis is less than the set value, then such a part at the current value of the wear rate can be finalized until the next inter-control check. Taking into account the wear rate of the same type of parts from the group when determining the allowable wear during their resource diagnostics becomes an urgent task. (Results and discussions) As a result of research, the article presents "Methodology for determining the main indicators of reliability of parts of agricultural machines with different wear rates" and "Methodology for determining the tolerance system of parts of agricultural machines with different wear rates". (Conclusions) The article presents the tolerance system that reduces the probability of failure of machine parts in operation. During resource diagnostics, those parts whose resource parameters exceed the tolerance are rejected.


2020 ◽  
pp. 66-71
Author(s):  
V. V. Ivashechkin ◽  
◽  
V. I. Kritskaya ◽  
V. N. Anufriev ◽  
A. N. Kondratovich ◽  
...  

The on-site investigation of groundwater intakes is carried out to obtain and update the actual parameters of the equipment and structures of a water intake, to optimize its operation modes with an analysis of their changes in time in order to plan maintenance and repair. This article discusses an improved methodology for examining individual elements and structures of groundwater intakes, which allows us to evaluate their current technical condition and to make a predictive calculation of changes in well productivity for the next period of operation based on the solution of the equations of dynamic equilibrium. The technique of clogging assessment allows determining ageing coefficients and approximate residual life of wells; the estimate of the rated pump pressure head reduction due to wear enables the pump testing during its operation at the well and timely replacement of the pump for routine repair; assessment of pipe sculling makes it possible to account for hydraulic resistance of lines connecting the wells to prefabricated water pipes during operation.


Author(s):  
P. Openko ◽  
V. Polishchuk ◽  
M. Mуronіuk ◽  
A. Kozyr

Maintenance of armaments and military equipment, implementation of a set of measures to maintain armaments and military equipment in working order are related to the need to solve the problem of ensuring the specified indicators of their efficiency, especially samples with long service life. Given the current state of the domestic armaments and military equipment park, it is important to study the experience of NATO member states in implementing adaptive maintenance and repair strategies, including maintenance and repair strategies. The aim of the article is to analyze the current state of use of adaptive strategies for maintenance and repair of weapons and military equipment in the world's leading countries with further substantiation based on its recommendations for their practical implementation during the organization of their operation in the Air Force of Ukraine. According to the results of research, a positive impact of the application of maintenance and repair strategy, including by solving the problem of minimizing the cost of operation of weapons and military equipment. As a result, substantiated and proposed the necessary conditions for the application of the strategy of their maintenance and repair, which are in service with the Armed Forces of Ukraine in technical condition, the implementation of which as an alternative to the use of service life (resource) of relevant samples control of the limit condition or the need for maintenance and repair of the product, which are accepted as a result of continuous (periodic) control of the parameters that determine the technical condition.


Author(s):  
Н.А. Сидоренков ◽  
Б.Г. Мартынов

Во время эксплуатации гидроманипуляторов (ГМ) возникает задача продления жизненного цикла ГМ. В настоящее время он составляет при полной нагрузке ГМ от 3 до 5 лет или 6000 моточасов до капитального ремонта. В зависимости от условий работы и обслуживания этот ресурс, по данным ПО «Подъемные машины», может быть израсходован за 8 мес. Руководством по эксплуатации ГМ определены пять видов ТО: ЕТО и четыре номерных. Причем в гарантийных обязательствах определен период работы ГМ до первого отказа. Он соответствует примерно 120 моточасам. Для продления срока службы ГМ до капитального ремонта необходимо перейти от обычной планово-предупредительной системы ТО и ремонта к проактивной системе. Основу проактивной системы ТО и Р составляет правильное управление техническим состоянием механизма с целью повышения его эксплуатационной надежности, определения оптимальной периодичности ТО и Р, что в свою очередь требует полной информации о техническом состоянии механизма и надежности его узлов и сопряжений. Цель проактивной системы ТО и Р – предупреждать отказ узлов и сопряжений механизма. Для реализации этой цели необходима разработка модели надежности ГМ и проведение статистических исследований отказов элементов механизма. Поэтому данная задача является актуальной. В настоящей статье приводится выражение, которое позволит формировать стратегию обслуживания данного типа манипуляторов для продления их срока службы. Цель исследования – разработка вероятностной модели надежности узлов и сопряжений ГМ для решения одной из задач управления техническим состоянием механизма с целью обоснования проактивной системы ТО и Р. During operation of hydraulic manipulators (GM), there arises the problem of extending the life cycle of the GM. Currently, it is under full load UM from 3 to 5 years or 6000 hours before overhaul. Depending on the conditions of operation and maintenance of this resource, according to «Lifting machines», can be used for 8 months. The user manual for the GM identifies five kinds: UTB and four plates. And in a warranty period defined by the work of the GM until the first failure. It corresponds to about 120 hours. To extend the service life of the GM overhaul need to move from conventional preventive system of maintenance and repair to a proactive system. The basis for proactive maintenance and R is the correct management of the technical condition of the mechanism with the purpose of increasing its ex-operational reliability, determining the optimal frequency and R, which in turn requires full information about the technical condition of the mechanism and reliability of its components and interfaces. The purpose of proactive maintenance and repair – to prevent failure of the nodes and interfaces of the mechanism. To achieve this goal it is necessary to develop reliability models of the GM and carrying out statistical studies of failures of elements of the mechanism. Therefore, this task is urgent. In this paper, we provide an expression that will form the servicing strategy for this type of manipulators to extend their service life. The purpose of the study: the development of probabilistic reliability models of the nodes and interfaces of GM to address one of the problems of control of technical condition of the mechanism in order to justify the proactive maintenance and R.


2021 ◽  
Vol 3 (144) ◽  
pp. 49-55
Author(s):  
Aleksey A. Solomashkin ◽  
◽  
Azamat F. Il’mukhametov

The article identifies the existing types of troubleshooting of self- propelled agricultural machinery. Taking into account the wear rate of the same type of parts from the group of parts of the same name when determining the permissible wear during their resource diagnostics is an urgent problem. The article presents the resource parameter and its influence on the reliability indicators of machine parts. (Research purpose) The research purpose is in determining the basic principles of the strategy of maintenance and repair of agricultural machinery in order to ensure control of the technical condition of machine parts, in particular, to increase the reliability of hydraulic drive parts. (Materials and methods) The article presents the options for maintenance strategies, the disadvantages and advantages of each of them. (Results and discussion) The article presents standard maintenance strategies: according to the need, planned preventive, according to the condition and justifies the optimal type of maintenance, taking into account the wear rate of each specific part. Authors performed an analysis of the algorithm for carrying out maintenance in each case individually. The tolerance is set based on the condition: if the current value of the controlled resource parameter during the next diagnosis turns out to be less than the set value, then such a part at the current value of the wear rate will be able to refine it until the next inter-control check. (Conclusions) The choice of a maintenance strategy has an important role in increasing the reliability of hydraulic drive parts of agricultural machines. A strategy has been developed that takes into account the wear rate of each specific part and the culling is carried out taking into account the wear rate of each part individually. Parts with a high wear rate are rejected first, and parts with a low wear rate are the last.


Author(s):  
Anzor L. Bolotokov ◽  
Valentin P. Lyalyakin

Injectors of diesel engines lose their functionality due to loss of tightness and jamming of the needle of the nozzle sprayer. (Research purpose) The research purpose is increasing the durability of injectors by upgrading the sprayer needle by performing a spiral screw groove on its guiding part. (Materials and methods) The article notes that the screw groove is performed by an elbor cutter on a lathe with the following parameters: an angle of 30 degrees, a radius of 0.133 millimeters, and a length of 21.71 millimeters. Authors conducted research to determine the resistance coefficient of the gap between the sprayer body and the sprayer with a spiral groove, depending on the fuel contamination. Authors performed non-motor bench accelerated tests of sprayers to determine the hydraulic density, the volume of fuel in the screw groove, and the resistance coefficient of the gap. (Results and discussion) Article notes that the decrease rate in the value of hydro density in upgraded sprayers is 1.24 times less than in serial ones. The article shows that due to the screw groove, the needle of the sprayer is rotated, and the working surfaces of the needle are not caught with the sprayer body, which ensures uniform wear with less intensity. (Conclusions) Upgrading the spray nozzle by applying a screw groove to its surface ensures that the surfaces are lubricated and creates a softened twisting impact instead of a hard hit on the spray nozzle seat.


Author(s):  
Н.В. Сидоренков ◽  
Б.Г. Мартынов ◽  
М.В. Тарабан

Из анализа исследований по разработке систем технического обслуживания и ремонта следует, что самая прогрессивная система, проактивная, предусматривает предупреждающие меры обслуживания, исходя из статистических результатов отказов наименее надежных узлов и сопряжений. Для обоснования проактивной стратегии профилактики (ПСП) необходимо определить надежность элементов гидроманипуляторов (ГМ), собрать статистические данные об отказах этих элементов, разработать правила, по которым проводятся техническое обслуживание и ремонт (ТО и Р). Для обоснования критерия ПСП наиболее подходит методика, в которой для формирования стратегии, во-первых, применялся анализ текущего технического состояния объекта и, во-вторых, вводилось понятие «относительная вероятность», представляющее разность между вероятностью безотказной работы и вероятностью отказа. На основе этого введено понятие «квантиль вероятности» и на его основании определены области благоприятной эксплуатации механизма, где 0 ≤ r(t) ≤ 1, время первого диагностирования tD 1, при котором r(t) = 0,75, время второго диагностирования tD 2 (корректировка кривой изменения диагностического параметра), при котором вероятности P(t) и Q(t) пересекаются (в идеальном случае это значение равно 0,5), и время, когда машину можно ставить на ремонт [r(t) = –0,5]. Но так как кривые вероятностей корректируются по результатам текущего технического состояния машин, то интенсивности безотказной работы и отказов имеют разные коэффициенты. А область профилактики определяется областью изменения функции относительной вероятности r(t) от +0,75 до –0,5. Точка, в которой r(t) = 0, определяет оптимальное время обслуживания машины. Эта методика позволяет руководителю самостоятельно принимать решения по управлению техническим состоянием машины. Но в случае таких механизмов, как ГМ, которые в основном работают сезонно и при полной нагрузке, необходимо ужесточение допустимых или даже предельных значений диагностических параметров, и при организации проактивной системы ТО и Р не обязательно определять кванты диагностирования. В данном случае осуществляется постоянный контроль, и поэтому необходимо определить критическую точку, после которой следует в обязательном порядке остановить ГМ, провести техническое обслуживание и предварительный ремонт. Цель исследования – обоснование проактивной стратегии профилактики ГМ, предусматривающей предупреждающие меры обслуживания, исходя из статистических результатов отказов наименее надежных узлов и сопряжений. Определены условия изменения параметров технического состояния для определения времени профилактики, контролируемые параметры, получено выражение для определения времени профилактики. From the analysis of the research on the development of systems of technical maintenance and repair of the most advanced system proactively provides preventative maintenance, based on the statistical results of the failures of the least reliable nodes and interfaces. To justify a proactive strategy of prevention (SRP) is necessary to determine the reliability of the GM, to collect statistical data on failures of these elements, to develop the rules by which IT is held and R. To justify the criterion of the SRP is the most suitable technique in which to form a strategy first, applied analysis of the current technical condition of the object and, secondly, introduced the concept of relative probabilities, representing the difference between the probability of failure and probability of failure. Based on this the notion of the quantile of probability and on the basis of identified areas of favourable operation of the mechanism, where 0 ≤ r(t) ≤ 1, the time of the first diagnosis, tD 1 , where r(t) = 0.75 and the time of the second diagnosis tD 2 (correction curve changes a scan parameter), in which the probability P(t) and Q(t) intersect (in the ideal case this value is equal to 0.5) and the time when the machine can be put in repair [r(t) = –0,5]. But since curves of probabilities are adjusted according to the results of the current technical state of machinery, the intensity of uptime and failures have different coefficients. And the prevention area is determined by the range of variation of the relative likelihood function r(t) from +0.75 to 0.5 in. The point at which r(t) = 0 determines the optimal maintenance time of the machine. This technique allows the Manager to make decisions on the management of the technical condition of the car. But in the case that such mechanisms as the GM, who work mainly seasonal and gender-Neu load need tightening or even the permissible limit values of diagnostic parameters and in the organization of proactive maintenance and repair is not necessary to determine the quanta of diagnosis. In this case, is monitored and it is therefore necessary to determine the critical point, after which it follows, necessarily, stop the GM, to carry out maintenance and advanced repairs. The purpose of the study. The rationale for a proactive strategy of prevention of the GM, providing preventative maintenance, on the basis of statistical results of the failures of the least reliable nodes and interfaces. The article defines the conditions for changing parameters of the technical condition to determine the time of prevention, control parameters and equation to determine the time prevention.


Author(s):  
V.I. Chernoivanov ◽  
◽  
V.A. Denisov ◽  
Yu.V. Kataev ◽  
A.A. Solomashkin ◽  
...  

The existing strategies of maintenance and repair are discussed and a new strategy based on the control of the residual life is presented. It is assumed that in the future, the main maintenance and repair operations will be focused on minimizing this residual life, i.e. on the increase in the service life. It is proved that this maintenance organization strategy for the maintenance and repair optimization allows minimizing the flow of random failures of components during operation and increasing their service life (for a group of the same components) to a maximum. The work on the selection and justification of the life parameters controlled in this strategy has been performed.


2019 ◽  
Vol 12 (1) ◽  
pp. 56-62 ◽  
Author(s):  
A. O. Nedosekin ◽  
A. V. Smirnov ◽  
D. P. Makarenko ◽  
Z. I. Abdoulaeva

The article presents new models and methods for estimating the residual service life of an autonomous energy system, using the functional operational risk criterion (FOR). The purpose of the article is to demonstrate a new method of durability evaluation using the fuzzy logic and soft computing framework. Durability in the article is understood as a complex property directly adjacent to the complex property of system resilience, as understood in the Western practice of assessing and ensuring the reliability of technical systems. Due to the lack of reliable homogeneous statistics on system equipment failures and recoveries, triangular fuzzy estimates of failure and recovery intensities are used as fuzzy functions of time based on incomplete data and expert estimates. The FOR in the model is the possibility for the system availability ratio to be below the standard level. An example of the evaluation of the FOR and the residual service life of a redundant cold supply system of a special facility is considered. The transition from the paradigm of structural reliability to the paradigm of functional reliability based on the continuous degradation of the technological parameters of an autonomous energy system is considered. In this case, the FOR can no longer be evaluated by the criterion of a sudden failure, nor is it possible to build a Markov’s chain on discrete states of the technical system. Assuming this, it is appropriate to predict the defi ning functional parameters of a technical system as fuzzy functions of a general form and to estimate the residual service life of the technical system as a fuzzy random variable. Then the FOR is estimated as the possibility for the residual life of the technical system to be below its warranty period, as determined by the supplier of the equipment.


2020 ◽  
Vol 4 (141) ◽  
pp. 114-122
Author(s):  
DAR’YA LEBEDEVA ◽  
◽  
ANNA KARPUNICHEVA

Large forces and significant thermal effects are created on the rolls when rolling sheets. The higher the stability of the rolls, the less downtime during their rerolling and higher productivity. (Research purpose) The research purpose is in analyzing the ways of restoring rolls and choose the most appropriate method for restoring these parts. (Materials and methods) The article presents the analysis of the scientific and technical literature on the topic of rolling production, methods for restoring large-sized machine parts of machine-building and metallurgical industries that work in difficult conditions and are subject to a high degree of wear. Authors try to solve the problem by means of comparative and logical analysis based on theoretical and empirical methods of scientific research. (Results and discussion) The article presents two groups of methods for restoring rolled rolls: banding and surfacing the working layer of the roll. Authors have analyzed each method in terms of technology, equipment, and feasibility. The article presents the advantages and disadvantages of the methods under consideration. (Conclusions) The most acceptable way to restore parts with a high degree of wear is surfacing. It is most efficient to apply submerged surfacing using an additional hot additive. Such surfacing, despite some complication of the equipment design, allows to deposit the metal on the roll with low heat input and in most cases in one pass. Surfacing using an additional hot additive allows to increase the productivity of the process by up to 250 percent while reducing the penetration depth by 2-3 times and saving energy by up to 40 percent.


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