Servicing is applied periodically in practice with the aim of restoring the system state and prolonging the lifetime. It is generally seen as an imperfect maintenance action which has a chief influence on the maintena...Servicing is applied periodically in practice with the aim of restoring the system state and prolonging the lifetime. It is generally seen as an imperfect maintenance action which has a chief influence on the maintenance strategy. In order to model the maintenance effect of servicing, this study analyzes the deterioration characteristics of system under scheduled servicing. And then the deterioration model is established from the failure mechanism by compound Poisson process. On the basis of the system damage value and failure mechanism, the failure rate refresh factor is proposed to describe the maintenance effect of servicing. A maintenance strategy is developed which combines the benefits of scheduled servicing and preventive maintenance. Then the optimization model is given to determine the optimal servicing period and preventive maintenance time, with an objective to minimize the system expected life-cycle cost per unit time and a constraint on system survival probability for the duration of mission time. Subject to mission time, it can control the ability of accomplishing the mission at any time so as to ensure the high dependability. An example of water pump rotor relating to scheduled servicing is introduced to illustrate the failure rate refresh factor and the proposed maintenance strategy. Compared with traditional methods, the numerical results show that the failure rate refresh factor can describe the maintenance effect of servicing more intuitively and objectively. It also demonstrates that this maintenance strategy can prolong the lifetime, reduce the total lifetime maintenance cost and guarantee the dependability of system.展开更多
This paper proposes a dynamic opportunistic preventive maintenance (PM) optimization policy for multi-unit series systems by integrating multi PM techniques. Two PM techniques, periodic PM and sequential PM, are consi...This paper proposes a dynamic opportunistic preventive maintenance (PM) optimization policy for multi-unit series systems by integrating multi PM techniques. Two PM techniques, periodic PM and sequential PM, are considered. Whenever one of the units reaches its reliability threshold, a PM action has to be performed on that unit. At that time the whole system has to be stopped and PM opportunities arise for the other unitsof the system. An optimal PM practice is determined by maximizing the short-term cumulative opportunistic maintenance (OM) cost savings for the whole system. Numerical examples are given to show how this approach works. Finally, a comparison between the proposed PM policy and the other policies is given.展开更多
To quantitatively identify the maintenance demand for each highway segments in the pavement maintenance scheme design,a mathematical model of uniform segment division was established and an approach of applying cluste...To quantitatively identify the maintenance demand for each highway segments in the pavement maintenance scheme design,a mathematical model of uniform segment division was established and an approach of applying cluster analysis theory to the uniform segment division and evaluation of pavement maintenance demand was proposed.The actual maintenance project of a highway carried out in Guangdong province was cited as an example to demonstrate the validity of the proposed method.It is proved that the cluster analysis can eliminate human factors in classification without being constrained by the quantities of samples,considering multiple pavement distress indexes and the continuity of samples.Thus it is evident that cluster analysis is an efficient analytical tool in uniform segment division and evaluation of maintenance demand.展开更多
The aging of machine can be slowed and the life of machine can be increased by implementing periodic predictive maintenance. In this article,an improvement factor considering maintenance cost,age of machine and learni...The aging of machine can be slowed and the life of machine can be increased by implementing periodic predictive maintenance. In this article,an improvement factor considering maintenance cost,age of machine and learning effect in the process of maintaining is constructed to describe the effect of periodic preventive maintenance. The model of improvement factor can be fitted through health index. Based on improvement factor with infinite time,cost function including preventive maintenance cost,minimal repair cost and replacement cost is explored. The unit cost and the optimized maintenance time interval based on limit of reliability are deduced. The process of optimization and an example are given.展开更多
Traditional modular design methods lead to product maintenance problems, because the module form of a system is created according to either the function requirements or the manufacturing considerations. For solving th...Traditional modular design methods lead to product maintenance problems, because the module form of a system is created according to either the function requirements or the manufacturing considerations. For solving these problems, a new modular design method is proposed with the considerations of not only the traditional function related attributes, but also the maintenance related ones. First, modularity parameters and modularity scenarios for product modularity are defined. Then the reliability and economic assessment models of product modularity strategies are formulated with the introduction of the effective working age of modules. A mathematical model used to evaluate the difference among the modules of the product so that the optimal module of the product can be established. After that, a multi-objective optimization problem based on metrics for preventive maintenance interval different degrees and preventive maintenance economics is formulated for modular optimization. Multi-objective GA is utilized to rapidly approximate the Pareto set of optimal modularity strategy trade-offs between preventive maintenance cost and preventive maintenance interval difference degree. Finally, a coordinate CNC boring machine is adopted to depict the process of product modularity. In addition, two factorial design experiments based on the modularity parameters are constructed and analyzed. These experiments investigate the impacts of these parameters on the optimal modularity strategies and the structure of module. The research proposes a new modular design method, which may help to improve the maintainability of product in modular design.展开更多
In this article, we assume that the product in the burn-in procedure only experiences continuous smooth degradation process, while in the field operation period the product experiences both continuous smooth degradati...In this article, we assume that the product in the burn-in procedure only experiences continuous smooth degradation process, while in the field operation period the product experiences both continuous smooth degradation process and shock process. The shock process can cause the product not only traumatic failure,but also additional abrupt degradation damage. After the system reliability model and maintenance model have been proposed, the optimal burn-in setting and age replacement duration are obtained under the considering of minimizing the long run average cost rate. A numerical example with the real data is analyzed to illustrate the application of the model.展开更多
Based on the log-linear virtual age process, an imperfect preventive maintenance policy for numerical control(NC)machine tools with random maintenance quality is proposed. The proposed model is a combination of the Ki...Based on the log-linear virtual age process, an imperfect preventive maintenance policy for numerical control(NC)machine tools with random maintenance quality is proposed. The proposed model is a combination of the Kijima type virtual age model and the failure intensity adjustment model. Maintenance intervals of the proposed hybrid model are derived when the failure intensity increase factor and the restoration factor are both random variables with uniform distribution. The optimal maintenance policy in infinite time horizon is presented. A numerical example is given when the failures of NC machine tools are described by the log-linear process. Finally, a discussion is presented to show how the optimal results depend on the different cost parameters.展开更多
Most warranty cost models based on preventive maintenance operations are assumed that products improve at each preventive maintenance （PM） operation and the failure rate is reduced to the failure rate of new product...Most warranty cost models based on preventive maintenance operations are assumed that products improve at each preventive maintenance （PM） operation and the failure rate is reduced to the failure rate of new products or to some specified level. To make warranty cost models more suitable to real operations, a modeling method of the PM warranty cost was proposed with the situation where each PM operation slowed the rate of product degradation. A warranty cost model was built on PM operations. On the basis of the cost model, both without and with reliability limit PM warranty policy, algorithms were presented to derive the optimal PM number and the optimal PM interval with an objective of minimizing expected total warranty cost over a t＇mite warranty period. Finally, to demonstrate the feasibility of the presented modeling method, Weibuil distribution cases were tested by numerical simulations. The simulation results indicate that the proposed modeling method is feasible and valid for resolving the optimal solution of the product warranty cost.展开更多
For the failures of two-dimensional product affected by the calendar time and usage time,traditional one-dimensional preventive maintenance can't meet the actual demand. Therefore,the concept of two-dimensional pr...For the failures of two-dimensional product affected by the calendar time and usage time,traditional one-dimensional preventive maintenance can't meet the actual demand. Therefore,the concept of two-dimensional preventive maintenance innovatively is proposed,in order to make decision for two-dimensional product through calendar time and usage time. Firstly, failure rate function expression of two-dimensional product is established and the process of two-dimensional preventive maintenance is analyzed in detail.Then a model of two-dimensional preventive maintenance to minimize the consumer's cost per unit of time is proposed. And examples are given to analyze the model's applicability and validity.Furthermore,the optimal two-dimensional preventive maintenance interval is derived. Finally,a brief discussion on future research area about two-dimensional maintenance is given.展开更多
Maintenance scheduling is essential and crucial for wind turbines (WTs) to avoid breakdowns andreduce maintenance costs. Many maintenance models have been developed for WTs’ maintenance planning, suchas corrective, p...Maintenance scheduling is essential and crucial for wind turbines (WTs) to avoid breakdowns andreduce maintenance costs. Many maintenance models have been developed for WTs’ maintenance planning, suchas corrective, preventive, and predictive maintenance. Due to communities’ dependence on WTs for electricityneeds, preventive maintenance is the most widely used method for maintenance scheduling. The downside tousing this approach is that preventive maintenance (PM) is often done in fixed intervals, which is inefficient. In thispaper, a more detailed maintenance plan for a 2 MW WT has been developed. The paper’s focus is to minimize aWT’s maintenance cost based on a WT’s reliability model. This study uses a two-layer optimization framework:Fibonacci and genetic algorithm. The first layer in the optimization method (Fibonacci) finds the optimal numberof PM required for the system. In the second layer, the optimal times for preventative maintenance and optimalcomponents to maintain have been determined to minimize maintenance costs. The Monte Carlo simulationestimates WT component failure times using their lifetime distributions from the reliability model. The estimatedfailure times are then used to determine the overall corrective and PM costs during the system’s lifetime. Finally,an optimal PM schedule is proposed for a 2 MW WT using the presented method. The method used in this papercan be expanded to a wind farm or similar engineering systems.展开更多
Presents the optimal preventive maintenance model established with the target function given through technical economic analysis, and failure rate and delay time distribution estimated from subjective data, which desc...Presents the optimal preventive maintenance model established with the target function given through technical economic analysis, and failure rate and delay time distribution estimated from subjective data, which describes the relationship between the total downtime and the preventive maintenance and can be used to determine the rational inspection interval and to minimize the total expected downtime per unit time.展开更多
In this study,an optimization model of a single machine system integrating imperfect preventive maintenance planning and production scheduling based on game theory is proposed.The costs of the production department an...In this study,an optimization model of a single machine system integrating imperfect preventive maintenance planning and production scheduling based on game theory is proposed.The costs of the production department and the maintenance department are minimized,respectively.Two kinds of three-stage dynamic game models and a backward induction method are proposed to determine the preventive maintenance(PM)threshold.A lemma is presented to obtain the exact solution.A comprehensive numerical study is provided to illustrate the proposed maintenance model.The effectiveness is also validated by comparison with other two existed optimization models.展开更多
The recursion relation of preventive maintenance (PM) cycle is built up concerning the concept of effective age and age setback factor proposed in this paper, which illustrates the dynamic relationship between failure...The recursion relation of preventive maintenance (PM) cycle is built up concerning the concept of effective age and age setback factor proposed in this paper, which illustrates the dynamic relationship between failure rate and preventive maintenance activity. And the nonlinear optimal PM policy model satisfying the reliability constraints in finite time horizon following Weibull distribution is proposed. The model built in this paper avoids the shortcoming of steady analytical PM model in infinite time horizon and can be used to aid scheduling the maintenance plan and providing decision supporting for job shop scheduling.展开更多
The contribution deals with the optimization of a sequential preventive maintenance schedule of a technical device. We are given an initial time-to-failure probability distribution, model of changes of this distributi...The contribution deals with the optimization of a sequential preventive maintenance schedule of a technical device. We are given an initial time-to-failure probability distribution, model of changes of this distribution after maintenance actions, as well as the costs of maintenance, of a device acquisition, and of the impact of failure. The maintenance timing and, eventually, its extent, are the matter of optimization. The objective of the contribution is two-fold: first, to formulate a proper (random) objective function evaluating the lifetime of the maintained device relatively to maintenance costs;second, to propose a numerical method searching for a maintenance policy optimizing selected characteristics of this objective function. The method is based on the MCMC random search combined with simulated annealing. It is also shown that such a method is rather universal for different problem specifications. The approach will be illustrated on an artificial example dealing with accelerated lifetime after each maintenance action.展开更多
A quick and valid method to determine preventive maintenance intervals is introduced in this paper.It applies the theory established by Barlow R.E.and Proschan F.in 1975,and It is based on the operation of actual age-...A quick and valid method to determine preventive maintenance intervals is introduced in this paper.It applies the theory established by Barlow R.E.and Proschan F.in 1975,and It is based on the operation of actual age-to-failure data and cost data for items to determine the optimum preventive maintenance interval by the technique of computer digital simulation on reliability.In comparison with the traditional methods,such as age-exploration,it can improve the rate of utilization and reduce the maintenance cost of the items.A longer period is needed to determine the maintenance interval by the traditional methods,while by the method introduced here it may shorten the time for the operational state to determine the maintenance interval.We can timely calibrate the interval by the computer in accordance with the statistics,and the application may be easily spreaded to the field of maintenance base.展开更多
In recent years, domestic expressway projects mostly adopt asphalt pavement, which is waterproof and can effectively prevent corrosion. This kind of pavement is relatively flat, convenient for maintenance and has a hi...In recent years, domestic expressway projects mostly adopt asphalt pavement, which is waterproof and can effectively prevent corrosion. This kind of pavement is relatively flat, convenient for maintenance and has a high degree of safety. Considering the close relationship between asphalt pavement operation technology and expressway operation quality, it is necessary to reasonably select pavement construction technology, strengthen quality control, fully ensure asphalt pavement operation effect and prolong highway service life. Based on this, it is of great significance to analyze the typical diseases and preventive maintenance technology of expressway asphalt pavement in this paper.展开更多
At present, thermal power is still an important part of Chinas electric energy. Real energy thermal power plants now have to achieve zero emissions, and carbon neutrality is not easy. This is a huge challenge, but als...At present, thermal power is still an important part of Chinas electric energy. Real energy thermal power plants now have to achieve zero emissions, and carbon neutrality is not easy. This is a huge challenge, but also a huge economic opportunity. This paper integrates the environmental benefits into the maintenance of the equipment, and the preventive maintenance strategy is adopted to minimize the unit carbon emission and cost in the life-cycle of the equipment by optimizing the number of preventive maintenance times. It provides an idea to reduce the carbon emission of equipment which is of great significance to realize carbon neutrality and environmental protection.展开更多
Preventive maintenance technology can effectively prevent pavement diseases and other problems, extend the service life of asphalt pavement, reduce the overall cost of periodic construction and maintenance, and improv...Preventive maintenance technology can effectively prevent pavement diseases and other problems, extend the service life of asphalt pavement, reduce the overall cost of periodic construction and maintenance, and improve economic benefits. Maintenance staff should use technology reasonably, so as to ensure the smooth road traffic.展开更多
At this stage, with the deepening of China's urbanization process, transportation is an important carrier of urban economic development. Highway maintenance treatment, as an important link, is the primary conditio...At this stage, with the deepening of China's urbanization process, transportation is an important carrier of urban economic development. Highway maintenance treatment, as an important link, is the primary condition to ensure the long-term sustainable development of highway engineering projects. Through preventive maintenance treatment, the highway maintenance project can achieve the ideal effect. This paper mainly discusses the application of preventive maintenance technology in highway maintenance engineering in order to improve the level of highway maintenance.展开更多
The distributed permutation flowshop scheduling problem(DPFSP)has received increasing attention in recent years,which always assumes that the machine can process without restrictions.However,in practical production,ma...The distributed permutation flowshop scheduling problem(DPFSP)has received increasing attention in recent years,which always assumes that the machine can process without restrictions.However,in practical production,machine preventive maintenance is required to prevent machine breakdowns.Therefore,this paper studies the DPFSP with preventive maintenance(PM/DPFSP)aiming at minimizing the total flowtime.For solving the problem,a discrete gray wolf optimization algorithm with restart mechanism(DGWO_RM)is proposed.In the initialization phase,a heuristic algorithm that takes into consideration preventive maintenance and idle time is employed to elevate the quality of the initial solution.Next,four local search strategies are proposed for further enhancing the exploitation capability.Furthermore,a restart mechanism is integrated into algorithm to avert the risk of converging prematurely to a suboptimal solution,thereby ensuring a broader exploration of potential solutions.Finally,comprehensive experiments studies are carried out to illustrate the effectiveness of the proposed strategy and to verify the performance of DGWO_RM.The obtained results show that the proposed DGWO_RM significantly outperforms the four state-of-the-art algorithms in solving PM/DPFSP.展开更多
基金supported by the National Defence Preresearch Foundation of China(Nos.51327020105,51304010206)
文摘Servicing is applied periodically in practice with the aim of restoring the system state and prolonging the lifetime. It is generally seen as an imperfect maintenance action which has a chief influence on the maintenance strategy. In order to model the maintenance effect of servicing, this study analyzes the deterioration characteristics of system under scheduled servicing. And then the deterioration model is established from the failure mechanism by compound Poisson process. On the basis of the system damage value and failure mechanism, the failure rate refresh factor is proposed to describe the maintenance effect of servicing. A maintenance strategy is developed which combines the benefits of scheduled servicing and preventive maintenance. Then the optimization model is given to determine the optimal servicing period and preventive maintenance time, with an objective to minimize the system expected life-cycle cost per unit time and a constraint on system survival probability for the duration of mission time. Subject to mission time, it can control the ability of accomplishing the mission at any time so as to ensure the high dependability. An example of water pump rotor relating to scheduled servicing is introduced to illustrate the failure rate refresh factor and the proposed maintenance strategy. Compared with traditional methods, the numerical results show that the failure rate refresh factor can describe the maintenance effect of servicing more intuitively and objectively. It also demonstrates that this maintenance strategy can prolong the lifetime, reduce the total lifetime maintenance cost and guarantee the dependability of system.
基金the National Natural Science Foundation of China (Nos. 50905115 and 70771065)the National High Technology Research and Development Program (863) of China (Nos. 2009AA043403,2009AA043000 and 2008042801)the Shanghai Natural Science Foundation (No. 09ZR1414400)
文摘This paper proposes a dynamic opportunistic preventive maintenance (PM) optimization policy for multi-unit series systems by integrating multi PM techniques. Two PM techniques, periodic PM and sequential PM, are considered. Whenever one of the units reaches its reliability threshold, a PM action has to be performed on that unit. At that time the whole system has to be stopped and PM opportunities arise for the other unitsof the system. An optimal PM practice is determined by maximizing the short-term cumulative opportunistic maintenance (OM) cost savings for the whole system. Numerical examples are given to show how this approach works. Finally, a comparison between the proposed PM policy and the other policies is given.
基金Sponsored by the Scientific and Technological Project on Road Maintenance Management Mode in Guangdong Province(Grant No.200407132)the Launching Fund Project for Dr.in Guangdong Province(Grant No.05300135)
文摘To quantitatively identify the maintenance demand for each highway segments in the pavement maintenance scheme design,a mathematical model of uniform segment division was established and an approach of applying cluster analysis theory to the uniform segment division and evaluation of pavement maintenance demand was proposed.The actual maintenance project of a highway carried out in Guangdong province was cited as an example to demonstrate the validity of the proposed method.It is proved that the cluster analysis can eliminate human factors in classification without being constrained by the quantities of samples,considering multiple pavement distress indexes and the continuity of samples.Thus it is evident that cluster analysis is an efficient analytical tool in uniform segment division and evaluation of maintenance demand.
基金the National Natural Science Foundation of China(Nos.50875168 and 50905115)
文摘The aging of machine can be slowed and the life of machine can be increased by implementing periodic predictive maintenance. In this article,an improvement factor considering maintenance cost,age of machine and learning effect in the process of maintaining is constructed to describe the effect of periodic preventive maintenance. The model of improvement factor can be fitted through health index. Based on improvement factor with infinite time,cost function including preventive maintenance cost,minimal repair cost and replacement cost is explored. The unit cost and the optimized maintenance time interval based on limit of reliability are deduced. The process of optimization and an example are given.
基金Supported by National Natural Science Foundation of China(Grant Nos.51205347,51322506)Zhejiang Provincial Natural Science Foundation of China(Grant No.LR14E050003)+3 种基金Project of National Science and Technology Plan of China(Grant No.2013IM030500)Fundamental Research Funds for the Central Universities of ChinaInnovation Foundation of the State Key Laboratory of Fluid Power Transmission and Control of ChinaZhejiang University K.P.Chao’s High Technology Development Foundation of China
文摘Traditional modular design methods lead to product maintenance problems, because the module form of a system is created according to either the function requirements or the manufacturing considerations. For solving these problems, a new modular design method is proposed with the considerations of not only the traditional function related attributes, but also the maintenance related ones. First, modularity parameters and modularity scenarios for product modularity are defined. Then the reliability and economic assessment models of product modularity strategies are formulated with the introduction of the effective working age of modules. A mathematical model used to evaluate the difference among the modules of the product so that the optimal module of the product can be established. After that, a multi-objective optimization problem based on metrics for preventive maintenance interval different degrees and preventive maintenance economics is formulated for modular optimization. Multi-objective GA is utilized to rapidly approximate the Pareto set of optimal modularity strategy trade-offs between preventive maintenance cost and preventive maintenance interval difference degree. Finally, a coordinate CNC boring machine is adopted to depict the process of product modularity. In addition, two factorial design experiments based on the modularity parameters are constructed and analyzed. These experiments investigate the impacts of these parameters on the optimal modularity strategies and the structure of module. The research proposes a new modular design method, which may help to improve the maintainability of product in modular design.
基金the National Natural Science Foundation of China(No.11171119)the Science and Technology Projects of Jiangxi Province Department of Education in 2012(No.GJJ12206)
文摘In this article, we assume that the product in the burn-in procedure only experiences continuous smooth degradation process, while in the field operation period the product experiences both continuous smooth degradation process and shock process. The shock process can cause the product not only traumatic failure,but also additional abrupt degradation damage. After the system reliability model and maintenance model have been proposed, the optimal burn-in setting and age replacement duration are obtained under the considering of minimizing the long run average cost rate. A numerical example with the real data is analyzed to illustrate the application of the model.
基金Project(51465034)supported by the National Natural Science Foundation of China
文摘Based on the log-linear virtual age process, an imperfect preventive maintenance policy for numerical control(NC)machine tools with random maintenance quality is proposed. The proposed model is a combination of the Kijima type virtual age model and the failure intensity adjustment model. Maintenance intervals of the proposed hybrid model are derived when the failure intensity increase factor and the restoration factor are both random variables with uniform distribution. The optimal maintenance policy in infinite time horizon is presented. A numerical example is given when the failures of NC machine tools are described by the log-linear process. Finally, a discussion is presented to show how the optimal results depend on the different cost parameters.
基金National Natural Science Foundation of China(No.60574054No.70771065No.70671065)
文摘Most warranty cost models based on preventive maintenance operations are assumed that products improve at each preventive maintenance （PM） operation and the failure rate is reduced to the failure rate of new products or to some specified level. To make warranty cost models more suitable to real operations, a modeling method of the PM warranty cost was proposed with the situation where each PM operation slowed the rate of product degradation. A warranty cost model was built on PM operations. On the basis of the cost model, both without and with reliability limit PM warranty policy, algorithms were presented to derive the optimal PM number and the optimal PM interval with an objective of minimizing expected total warranty cost over a t＇mite warranty period. Finally, to demonstrate the feasibility of the presented modeling method, Weibuil distribution cases were tested by numerical simulations. The simulation results indicate that the proposed modeling method is feasible and valid for resolving the optimal solution of the product warranty cost.
基金Mechanical Engineering College Research Foundation,Chian(No.13038)
文摘For the failures of two-dimensional product affected by the calendar time and usage time,traditional one-dimensional preventive maintenance can't meet the actual demand. Therefore,the concept of two-dimensional preventive maintenance innovatively is proposed,in order to make decision for two-dimensional product through calendar time and usage time. Firstly, failure rate function expression of two-dimensional product is established and the process of two-dimensional preventive maintenance is analyzed in detail.Then a model of two-dimensional preventive maintenance to minimize the consumer's cost per unit of time is proposed. And examples are given to analyze the model's applicability and validity.Furthermore,the optimal two-dimensional preventive maintenance interval is derived. Finally,a brief discussion on future research area about two-dimensional maintenance is given.
基金the Natural Sciences and Engineering Research Council of Canada(Grant No.RGPIN-2019-05361)and the University Research Grants Program.
文摘Maintenance scheduling is essential and crucial for wind turbines (WTs) to avoid breakdowns andreduce maintenance costs. Many maintenance models have been developed for WTs’ maintenance planning, suchas corrective, preventive, and predictive maintenance. Due to communities’ dependence on WTs for electricityneeds, preventive maintenance is the most widely used method for maintenance scheduling. The downside tousing this approach is that preventive maintenance (PM) is often done in fixed intervals, which is inefficient. In thispaper, a more detailed maintenance plan for a 2 MW WT has been developed. The paper’s focus is to minimize aWT’s maintenance cost based on a WT’s reliability model. This study uses a two-layer optimization framework:Fibonacci and genetic algorithm. The first layer in the optimization method (Fibonacci) finds the optimal numberof PM required for the system. In the second layer, the optimal times for preventative maintenance and optimalcomponents to maintain have been determined to minimize maintenance costs. The Monte Carlo simulationestimates WT component failure times using their lifetime distributions from the reliability model. The estimatedfailure times are then used to determine the overall corrective and PM costs during the system’s lifetime. Finally,an optimal PM schedule is proposed for a 2 MW WT using the presented method. The method used in this papercan be expanded to a wind farm or similar engineering systems.
文摘Presents the optimal preventive maintenance model established with the target function given through technical economic analysis, and failure rate and delay time distribution estimated from subjective data, which describes the relationship between the total downtime and the preventive maintenance and can be used to determine the rational inspection interval and to minimize the total expected downtime per unit time.
基金Sponsored by the National Natural Science Foundation of China(Grant Nos.72061022 and 72171037).
文摘In this study,an optimization model of a single machine system integrating imperfect preventive maintenance planning and production scheduling based on game theory is proposed.The costs of the production department and the maintenance department are minimized,respectively.Two kinds of three-stage dynamic game models and a backward induction method are proposed to determine the preventive maintenance(PM)threshold.A lemma is presented to obtain the exact solution.A comprehensive numerical study is provided to illustrate the proposed maintenance model.The effectiveness is also validated by comparison with other two existed optimization models.
基金Natural Science Foundation of China (No. 59889505)
文摘The recursion relation of preventive maintenance (PM) cycle is built up concerning the concept of effective age and age setback factor proposed in this paper, which illustrates the dynamic relationship between failure rate and preventive maintenance activity. And the nonlinear optimal PM policy model satisfying the reliability constraints in finite time horizon following Weibull distribution is proposed. The model built in this paper avoids the shortcoming of steady analytical PM model in infinite time horizon and can be used to aid scheduling the maintenance plan and providing decision supporting for job shop scheduling.
文摘The contribution deals with the optimization of a sequential preventive maintenance schedule of a technical device. We are given an initial time-to-failure probability distribution, model of changes of this distribution after maintenance actions, as well as the costs of maintenance, of a device acquisition, and of the impact of failure. The maintenance timing and, eventually, its extent, are the matter of optimization. The objective of the contribution is two-fold: first, to formulate a proper (random) objective function evaluating the lifetime of the maintained device relatively to maintenance costs;second, to propose a numerical method searching for a maintenance policy optimizing selected characteristics of this objective function. The method is based on the MCMC random search combined with simulated annealing. It is also shown that such a method is rather universal for different problem specifications. The approach will be illustrated on an artificial example dealing with accelerated lifetime after each maintenance action.
文摘A quick and valid method to determine preventive maintenance intervals is introduced in this paper.It applies the theory established by Barlow R.E.and Proschan F.in 1975,and It is based on the operation of actual age-to-failure data and cost data for items to determine the optimum preventive maintenance interval by the technique of computer digital simulation on reliability.In comparison with the traditional methods,such as age-exploration,it can improve the rate of utilization and reduce the maintenance cost of the items.A longer period is needed to determine the maintenance interval by the traditional methods,while by the method introduced here it may shorten the time for the operational state to determine the maintenance interval.We can timely calibrate the interval by the computer in accordance with the statistics,and the application may be easily spreaded to the field of maintenance base.
文摘In recent years, domestic expressway projects mostly adopt asphalt pavement, which is waterproof and can effectively prevent corrosion. This kind of pavement is relatively flat, convenient for maintenance and has a high degree of safety. Considering the close relationship between asphalt pavement operation technology and expressway operation quality, it is necessary to reasonably select pavement construction technology, strengthen quality control, fully ensure asphalt pavement operation effect and prolong highway service life. Based on this, it is of great significance to analyze the typical diseases and preventive maintenance technology of expressway asphalt pavement in this paper.
文摘At present, thermal power is still an important part of Chinas electric energy. Real energy thermal power plants now have to achieve zero emissions, and carbon neutrality is not easy. This is a huge challenge, but also a huge economic opportunity. This paper integrates the environmental benefits into the maintenance of the equipment, and the preventive maintenance strategy is adopted to minimize the unit carbon emission and cost in the life-cycle of the equipment by optimizing the number of preventive maintenance times. It provides an idea to reduce the carbon emission of equipment which is of great significance to realize carbon neutrality and environmental protection.
文摘Preventive maintenance technology can effectively prevent pavement diseases and other problems, extend the service life of asphalt pavement, reduce the overall cost of periodic construction and maintenance, and improve economic benefits. Maintenance staff should use technology reasonably, so as to ensure the smooth road traffic.
文摘At this stage, with the deepening of China's urbanization process, transportation is an important carrier of urban economic development. Highway maintenance treatment, as an important link, is the primary condition to ensure the long-term sustainable development of highway engineering projects. Through preventive maintenance treatment, the highway maintenance project can achieve the ideal effect. This paper mainly discusses the application of preventive maintenance technology in highway maintenance engineering in order to improve the level of highway maintenance.
基金supported by the National Natural Science Foundation of China(Nos.62473186 and 62273221)Natural Science Foundation of Shandong Province(No.ZR2024MF017)Discipline with Strong Characteristics of Liaocheng University Intelligent Science and Technology(No.319462208).
文摘The distributed permutation flowshop scheduling problem(DPFSP)has received increasing attention in recent years,which always assumes that the machine can process without restrictions.However,in practical production,machine preventive maintenance is required to prevent machine breakdowns.Therefore,this paper studies the DPFSP with preventive maintenance(PM/DPFSP)aiming at minimizing the total flowtime.For solving the problem,a discrete gray wolf optimization algorithm with restart mechanism(DGWO_RM)is proposed.In the initialization phase,a heuristic algorithm that takes into consideration preventive maintenance and idle time is employed to elevate the quality of the initial solution.Next,four local search strategies are proposed for further enhancing the exploitation capability.Furthermore,a restart mechanism is integrated into algorithm to avert the risk of converging prematurely to a suboptimal solution,thereby ensuring a broader exploration of potential solutions.Finally,comprehensive experiments studies are carried out to illustrate the effectiveness of the proposed strategy and to verify the performance of DGWO_RM.The obtained results show that the proposed DGWO_RM significantly outperforms the four state-of-the-art algorithms in solving PM/DPFSP.
