جستجوی مقالات مرتبط با کلیدواژه « نگهداری و تعمیرات » در نشریات گروه « فنی و مهندسی »

Both in the academic environment and in the realm of operation, it has been shown that there is a close relationship between product quality and maintenance of equipment. Thus, coordination of the decisions associated with maintenance and quality can lead to decrease in operational costs of a production system and improve the overall productivity. To coordinate the decisions related to maintenance and statistical process control, this thesis develops integrated mathematical models. The system performance is compared in two states: (1) while there is a coordination between the decisions of maintenance and SPC, (2) while the decisions of maintenance and SPC are conducted separately, and indeed, there is no coordination between SPC and maintenance. To determine the system performance in state 1, an integrated model of SPC and maintenance is developed. Optimization of the integrated model determines the value of ECT in state 1. To determine the system performance in the uncoordinated state,i.e., state 2, the following steps are performed: (1) a stand-alone model of maintenance is proposed, (2) a stand-alone model of SPC is developed, (3) according to the results of optimization of step 1 and 2, the value of ECT in the uncoordinated state is computed. Finally, comparison of the values of ECT in the coordinated state and uncoordinated state clarifies that, due to the performance of the integrated model, how much saving in operational cost is obtained. For the systems investigated in the thesis, using factorial designs, the effect of the system parameters on the decision variables and the objective function is analyzed. Also, it is investigated that, with respect to the operational costs, what circumstances are more suitable for implementing the integrated models of SPC and maintenance. According to the results of the study, integration of the decisions associated with maintenance and SPC leads to a better performance. The amount of saving obtained from the coordination is significant for the different production systems.

Health index is a tool to evaluate the functional condition of an equipment with the aim of improving its operational performance. In this research, the types of models available in the field of asset health index estimation along with their challenges and limitations were examined, based on a developed model. The proposed model was implemented in five different types of wind tunnel equipment fans, due to their significant maintenance and repair costs. The model proposed in this research in order to estimate the health index includes steps such as: 1) selecting the equipment and defining its class, 2) evaluating the effect of loading factors and location, 3) calculating the aging rate, 4) achieving the initial health index at age t and 5) evaluation of load effect, modifiers of health index and reliability, and calculation of current health index. Examining the values obtained from the fan health index, in the form of a graphic design, showed that it is possible to determine the speed of failure rate and the functional life of the equipment. The results of this research can be used in choosing the appropriate strategy for maintenance and repairs with the aim of improving the operational performance of other equipment.

Failure to define the indicators and sub-indicators for measuring the performance of Repair and Maintenance (R&M) activities is one of the significant issues in a building to increase its life expectancy. Evaluation of R&M system in a building is one of the key factors in improving the quality of R&M performance steps. Therefore, to implement appropriate strategies, the criteria affecting on R&M system must be identified. Also, choosing the proper net policy is a strategic decision-making problem that effectively reduces the cost and longevity of buildings. In this research, by using the experts’ opinion and the Delphi method, the indicators and sub-indicators affecting the R&M system were identified, and those indicators were graded using the decision tool. The existing buildings in Karaj city as a case study were then considered to evaluate the proposed system. Analysis of the results shows that the safety index has the highest grade according to the experts’ opinion, but by reviewing the results of the case study, this rank was assigned to the health criterion. Then, by using the SWARA technique, the most critical policies affecting buildings’ R&M are identified among Emergency Maintenance (EM), Breakdown Maintenance, Corrective Maintenance (CM), Preventive Maintenance (PM), Predictive Maintenance (PdM), Total Productive Maintenance (TPM), Proactive maintenance. Applying the VIKOR method and the results of both approaches revealed that Corrective Maintenance (CM) and Breakdown Maintenance (BM) policies are the best for buildings, R&M policies.

Nowadays, due to the large volume of assets in the water and wastewater industry and its impact on the development and sustainability of other industries, specific attention to this industry becomes more apparent. Since there are various equipments in this industry, achieving efficiency and proper performance in this equipment and maintenance system has been identified and then, with fuzzy decision-making which can be envisaged as innovation of this project, the ranking of the factors has been worked upon. The results of this requires timely maintenance and repairs. This study has evaluated the efficiency of these systems by considering the importance of paying attention to the factors that affect the performance of the maintenance system and consequently the quality and reliability. Considering the various evaluation and ranking methods, the present research has investigated this issue in two phases using operations research techniques and fuzzy decision making. In the first, the pivotal factors on the Alborz Province Water and Sewage Company’s function of upkeep study shows that water and sewage companies by employing of technological conditions that include quality and utilization of innovative technologies that have highest priority in comparison to other important alternatives with ultimate importance of 0.3123 could increase productivity.

At last time for using helicopter very difficult due to lack of identification but todays the helicopter very well for transport, any things. The main Identification Factors Effects to Leadership Management for a Helicopter Flight Operational by calculating costs for flight and maintenance planning . For this purpose, to management flight operation, maintenance by availability, sustainability, serviceability factors. In this regard, increasing the capability of operational readiness is one of the most important characteristics for this goal by Flight and maintenance planning model. Diverse factors effect on the operational readiness in helicopter flight systems, for example, availability of the aircrafts and other important components. Scheduling the aircrafts flight aims to manage different components influencing the operational readiness. Scheduling includes the maintaining process to A study on the different models by experiment. Expert method in term of operational readiness in helicopter flight systems are proposed in this paper. The proposed models cover the issue in diverse topics. Todays for maintain and promotion flight operation by management flight operation. Management cost and evaluation credit. security at world will activity company air lines by active flight crew, capability helicopters and pension or emolument.

Road network is one of the main infrastructure developments and it is considered as the national capital. Maintaining this huge capital requires long-term planning and continuous activity of maintenance. In the past, traditional maintenance methods were focused on activities intrinsically or structures. Because preventative maintenance measures to increase pavement life-time service-systems and decrease the cost of long-term facilities, the theory carry out maintenance before the start of the collapse of the pavement is been considered by managers. Crowded intercity routes of Mazandaran province, especially in the tourist region studied in this research that was chosen because of high traffic and vehicle traffic. In order to solve this issue, after coding in MATLAB software, based on mathematical models and algorithms different states based on different period, the number of choosing the path of repairs category and a limited budget is defined, then desired results is obtained. The characteristics of solutions is defined in different states and changes in cost, utility and total number of selected routes as well as maintenance paths of selection from each category is analyzed.

Failure detection of complex industrial equipment such as locomotives is a challenging tack in maintenance process. Failure to timely diagnose the cause of locomotive failure, in addition to reducing access time, will cause disruption to the rail network, increase excess train stops and other adverse events. With the advances made in recent years, the amount of data stored in new locomotives is increasing. In different ways, the knowledge contained in the data can be extracted and used to increase the productivity of the organization. By pattern analysis of failure detection of locomotives, the cause of many failures can be discovered and repair time can be reduced. Among the available methods, data mining techniques can be mentioned. The present study uses data mining and Apriori algorithm to discover meaningful rules from the data in locomotives, with the aim of improving the efficiency of the failure detection process. The result of this study is the discovery of 20 frequent occurrence in passenger locomotives, 18 two-component laws and 2 three-component laws, and its key achievement is the improvement of locomotives maintenance in a short period of time in the Railway of the northeastern region of Iran. Use of the discovered laws in the future can eliminate many out-of-schedule stops of passenger trains and also significantly reduce the cost of locomotive maintenance. It is estimated that using only one of the mentioned laws alone can reduce the cost of Iran's railways by about ten billion rials per year.

Given the importance of the repair and maintenance process in keeping equipment and facilities ready for use, it is necessary to assess the process and performance of maintenance indicators regularly so that the repair and maintenance is planned and upgraded. The main purpose of the building repair and maintenance is to control the equipment, facilities, and various building components to determine productivity and optimize their ability to achieve the highest efficiency. As measuring the efficiency is one of the most important performance evaluation methods, evaluating the efficiency of the repair and maintenance is one of the qualitative factors to improve this system. The purpose of this study is to evaluate the efficiency and performance of the repair and maintenance in buildings using a quantitative and provable data envelopment analysis (DEA) method. The results of this study show that the DEA is a suitable method for evaluating the efficiency and productivity of the decision-making units (DMUs).Therefore, first, the questionnaire is formed based on the building repair and maintenance system parameters extracted from Topic 22 of the National Building Code, the ranks are determined, and the results obtained from the sub-indices are integrated by the mean ranking index, and the qestionnaires’ reliability is measured using Cronbach's alpha. Finally, after defining the input and output indices by the DEA, the efficiency of each building and its cost are determined based on the repair and maintenance indices(In a case study of the city of Karaj). The results showed that the minimum and maximum reduction of the cost of charging, maintenance and repair of the building to convert them into an efficient building is 1% and 80%, respectively. Moreover, based on the results, it is possible to provide suggestions to improve the efficiency of the inefficient buildings based on the repair and maintenance costs.

The purpose of this study is to present a local strategy in the field of maintenance and explain its various dimensions and components, taking into account the successful global experiences, special considerations and requirements governing Iran's economic and industrial ecosystem, resistive economy policies, indigenous culture, indigenous moral values, and maintenance issues. The statistical population of this study consists of the experts in the field of maintenance and repairs in the country.The sampling is performed in a targeted manner and to the extent of achieving theoretical saturation, which is obtained through interviews with twenty experts. The collected data are analysed using the data-based method and their open, axial and selective codes are extracted at each stage. The final research model consists of seventeen main themes in four areas of soft strategy infrastructure, technical foundations, manpower continuity and appropriate support. The research findings are used in a military organization and the results are briefly reported in the form of a research action.

Multiple variables and subsystems increase the complexity of safety-based maintenance modeling in large systems, including power plants. This paper is modeling the power plant maintenance system by considering safety indicators. Then it simulates and analyzes the behavior of the designed model for a numerical sample. Regarding the literature review, a causal loop diagram of the maintenance system for power plant was designed and a safety subsystem was added to the model, based on the experts’ opinion, and finally the stock and flow diagram was formulated using AnyLogic software. The model was simulated in three scenarios including scenario one, training, scenario two, adding new equipment in the seventh year and scenario three, a combination of adding new equipment and training. The first simulation confirmed that increasing the training rate reduced the breakdown rate and equipment failure rate up to the sixth year, as well as reducing the accident rate and cost and increasing safety until the fifth year. Current costs increased. The second indicated that the addition of eight new equipment in the seventh year will improve the model up to 15 years later, and the amount of profit from the second year to the fifteenth year is more than scenario one and three. The combination of scenarios one and two, the optimal scenario, causes a greater amount of safety, a lower failure rate from the sixth year onward, a lower accident rate and cost, and a lower current cost from the fifth year onward.

Estimated wage for maintenance activities depends on time, cost and quality factors. Therefore, in the cost section, managing wages is important that with proper planning can lead to significant savings in organizational costs. In the discussion of the wage of maintenance, according to the rate approved by the government and at firms and repair shops, according to the rate approved by the union, payments are made. Due to the fact that the quality of repair work varies from one level to another, the wage must be commensurate with the quality and level of the repair work. In this paper, we present an output-oriented model (output-axis, meaning that people's pay depends on their output) in order to accurately calculate the wage, as well as create a bargaining framework in the maintenance department using the Overall Craft Effectiveness index at the levels Different maintenance activities are outsourced. In order to test the model, data from the automotive industry has been used in various market brands under the supervision of legal entities. This method, in addition to motivating, will make a person who is more effective and produces a higher quality output, receives a fair wage commensurate with it

Maintenance system is a dynamic and structured system, consisting of a coordination set of activities that are created to maintain, maintain and repair facilities and equipment in the organization and based on customer satisfaction is implemented as a whole consisting of Integrated components are a coherent set of activities with integrated resources, culture, structure and management system designed to create a dynamic and vibrant structure to control an environment with chaotic characteristics in which the outcome of activities is greater than the individual. The present study has been written with the aim of presenting a maintenance model in the Armed Forces based on the views of Imam Khamenei.The present study uses the library method and the study of His Majesty's orders in meetings with commanders and officials of the Armed Forces and visits to military complexes, information was collected and content analysis was used to analyze the data. Among the methods of qualitative data analysis, "content analysis" is a process for analyzing textual data and converts scattered and diverse data into rich and detailed data. ‌Based on the model of content analysis by studying in His Majesty's orders, 74 basic themes, 12 constructive themes under the titles of "religious faith and belief", "innovation and creativity", "national self-reliance and independence", "care and saving", " "Manpower", "Re-engineering", "Equipment readiness", "Equipment efficiency", "Revolutionary life", "Use of existing facilities", "Basic care" and "Consequences of the revolutionary note" are extracted, all of which are constructive themes under one They became known as the "revolutionary note".

With the expansion of industries and companies, the number and dimensions of buildings and facilities of organizations are increasing, which increases the value of these assets, increasing the importance of maintenance and repairs of these facilities. On the other hand, as the number of assets increases, the process of managing their maintenance and repairs becomes more difficult than in the past. It is better to define a model for scheduling the maintenance, to proposed the optimal time and order of maintenance program. In this paper, by the combination of Genetic algorithm (GA) and Particle Swarm Optimizations (PSO), a new model for scheduling maintenance for organizations with different locations is presented. The main contributions of this paper are (a) Definition of the main problem in multiple locations and consideration of travel times between each location. (b) Consideration of different work skills for maintenance plan. (c) Consideration of the possibility of outsourcing each task. Considering 10 scenarios for the number of facilities, 3 scenarios for the number of specialists in each location and 2 scenarios for the type of costs, the results show the better performance of the proposed model in compare of three different models as Gulpiras model, Koay’s Model, and Javanmard’s model, where the results have been shown, by using the proposed model, it is possible to reduce costs just over by 34%.

Today, maintenance due to increased complexity in the production process and product variety has faced the change and caused the paradigm shift in implementation of maintenance strategies that in this procedure, maintenance strategies based on status has changed to strategies based on reliability. The aim of the study is evaluating of risk of equipment failure by a subset technique of possible risk assessment, which is called Fault Tree Analysis. Fault tree analysis is a technique based on failure and component-oriented, which started with an undesirable event, and by using a backward system process, determine the causes of this event. During this process, a fault tree is drawn to describe graphically the events and their relationship to the occurrence of the top event. Fault Tree is a qualitative model that offers a lot of useful information that cause an undesirable event. On the other hand, by using of Boolean algebra equations and by considering the relationship between the specified causes, quantitative analysis also can be done. In this study, emergency stop of gas turbine due to a malfunction in lubrication system as the top event (undesirable event) is considered and by considering the causes of failure to the occurrence of the event and drawing the fault tree, both quantitative and qualitative assessments on system failures, has been done. In addition, how to use the results of the risk assessment of failures in order to optimize the processes of maintenance management system has been presented.

Using the services available in different organizations, you make use of the international organization, providing consulting services. Internet activities, given access to the island, cannot be reorganized into international organizations and can present you with a competitor and thus become Brazil. Paying attention to the dedicated task and switching specific features as a vehicle, body, sensitive and gravitational imposes a lot of costs on the organization and you can send us many problems as well. Use the best of the most important reasons This is useful, you can use actual services, use specialists on the Internet and use specialists on the Internet, using specialized facilities, access to specialists, feasibility, usability skills, quality, Synchronization using modified methods, and a variety of contractors can use these applications and their applications, applications and scheduling, with good quality, synchronization using modified methods, and Be a variety of contractors. Imagine. This research has come to a conclusion in two phases: At the proposed level, the metrics of outsourcing and the economics of resistance are published with the study of scientific literature and the free consulting firm Advertising Distribution and we offer its basics. Secondly, with the help of empowerment economic criteria, outsourcing criteria using different criteria accessibility techniques (TOPSIS model) are also prioritized. By visiting your site, you can display your information by visiting your site.

Oil analysis is one of the Condition Monitoring methods to detect abnormal corrosion of mechanical equipment and systems.The wear and tear is caused by the same wear and tear on the inside of the machine. Knowing the metallurgy of the materials used to make the engine's internal components and the material of the particles in the oil can make predictions about the probability of various defects. In this study, we investigate the erosive behavior of road construction engines with respect to the status of oil-based elements of line analysis. These baselines were obtained by data mining methods of oil analysis experiments based on normal distribution and statistical methods along with recorded failures in the maintenance unit over a period of about three years.According to the analysis of erosive particles and elements present in various engine components, especially cylinder and cylinder alloy structure, alloy used in the rod structure, base metal material used in bearings, type of engine oil and oil performance, probable defects and probable investigations Are determined. Indicators studied in oil analysis are: viscosity, silica, coarse ferrous particles, erosive metals such as iron, aluminum, lead, copper, tin, chromium. Other parameters to consider include: Whether or not to use oil additives  Use of acid neutralizers, cleaners, oxidizers, and anti-wear and rust agents. Antifreeze consumption and its type •          The type of service and repairs performed on the devices (if repaired, reported a problem and if possible, provided images of parts that have been damaged or damaged) •          The environment where the machines are used (mines, roads, dusty environments, etc.).