Optimal maintenance strategy for systems with two failure modes

This paper considers a single-unit system subject to two types of failures: a traditional catastrophic failure and a two-stage delayed failure. Periodic inspections are carried out to identify the defective stage of the two-stage failure process, whereas preventive replacements are implemented to avoid any potential failure due to the catastrophic failure mode. We construct a basic maintenance model and then extend it to the cases of imperfect inspections (i.e., inspections that do not always notice a defective state). We analyze the renewal process of the system and establish the expected long-run cost rate (ELRCR). The optimal inspection period and preventive replacement interval are determined by minimizing the ELRCR. A case study on infusion pumps is presented to illustrate the proposed model

ANALYTIC HIERARCHY PROCESS APPROACH FOR SELECTION AND EVALUATION OF MAINTENANCE STRATEGY

Selection of suitable maintenance strategy has always been vital for the industries. The selection deals with the large number of tangible and intangible attributes. Estimation of the optimal maintenance strategies for the different failure modes represents the main complexity of the selection process. Equipment, as well as the available maintenance facilities, tools and capabilities delimit the selection of the type of maintenance. In many cases, the selection requires the knowledge of various factors such as safety aspects, environmental problems, costs and budget constraints, manpower utilization and etc. This project presents Analytic Hierarchy Process (AHP) approach to define the best strategies for maintenance of mechanical systems or equipment. The main objective is to develop an application, which would assist in quick selection of maintenance strategy using AHP. User friendly application is developed to assist the user in selection, and weighting the criterions and alternatives. The final output is the scores of each maintenance strategy that will aid in ranking. However, the user is also offered predetermined sets of weightings of criterions and alternatives that are dependent on risk analysis results. Since risk contributes towards decision making by affecting the weighting considerations, the classic definition of risk that accounts both the probability and consequence of accident or failure is also considered, and equipment can be categorized into four risk zones based user’s judgment or assessment results, if any conducted. The developed decision framework is tested for validity of results with help of two case studies. The results obtained prove the validity of developed framework

ANALYTIC HIERARCHY PROCESS APPROACH FOR SELECTION AND EVALUATION OF MAINTENANCE STRATEGY

Selection of suitable maintenance strategy has always been vital for the industries. The selection deals with the large number of tangible and intangible attributes. Estimation of the optimal maintenance strategies for the different failure modes represents the main complexity of the selection process. Equipment, as well as the available maintenance facilities, tools and capabilities delimit the selection of the type of maintenance. In many cases, the selection requires the knowledge of various factors such as safety aspects, environmental problems, costs and budget constraints, manpower utilization and etc. This project presents Analytic Hierarchy Process (AHP) approach to define the best strategies for maintenance of mechanical systems or equipment. The main objective is to develop an application, which would assist in quick selection of maintenance strategy using AHP. User friendly application is developed to assist the user in selection, and weighting the criterions and alternatives. The final output is the scores of each maintenance strategy that will aid in ranking. However, the user is also offered predetermined sets of weightings of criterions and alternatives that are dependent on risk analysis results. Since risk contributes towards decision making by affecting the weighting considerations, the classic definition of risk that accounts both the probability and consequence of accident or failure is also considered, and equipment can be categorized into four risk zones based user’s judgment or assessment results, if any conducted. The developed decision framework is tested for validity of results with help of two case studies. The results obtained prove the validity of developed framework

Managing Well Integrity using Reliability Based Models

Imperial Users onl

Predictive maintenance for the heated hold-up tank

We present a numerical method to compute an optimal maintenance date for the test case of the heated hold-up tank. The system consists of a tank containing a fluid whose level is controlled by three components: two inlet pumps and one outlet valve. A thermal power source heats up the fluid. The failure rates of the components depends on the temperature, the position of the three components monitors the liquid level in the tank and the liquid level determines the temperature. Therefore, this system can be modeled by a hybrid process where the discrete (components) and continuous (level, temperature) parts interact in a closed loop. We model the system by a piecewise deterministic Markov process, propose and implement a numerical method to compute the optimal maintenance date to repair the components before the total failure of the system.Comment: arXiv admin note: text overlap with arXiv:1101.174

Development and implementation of preventive-maintenance practices in Nigerian industries.

A methodology for the development of PM using the modern approaches of FMEA, root-cause analysis, and fault-tree analysis is presented. Applying PM leads to a cost reduction in maintenance and less overall energy expenditure. Implementation of PM is preferable to the present reactive maintenance procedures (still prevalent in Nigeria