Maintenance Alternatives Research Articles

Development of Fuzzy Multi Criteria Decision Making Method for Selection of Optimum Maintenance Alternative

An optimal maintenance strategy is a key support to production in the manufacturing industry. This paper present a fuzzy approach based on Multi-Criteria Decision-Making (MCDM) methodology for selecting the optimal maintenance alternative. In the present work the criticality of each equipment is achieved by ranking (based on production loss).It is very difficult to quantify the qualitative factors in exact numerical value. These factors can be expressed in the linguistics terms which can be translated into mathematical measures by using fuzzy sets & system theory. The study problem to develop a fuzzy decision approach to rank the suitable maintenance alternative. The objective of this paper is to propose fuzzy frame work based on fuzzy number theory to solve optimal maintenance alternative which includes decision criteria analysis, weight assessment & decision model development. The approach can aid formulating a cost-effective maintenance strategy for a manufacturing plant.

Optimization of fatigue maintenance strategies based on prognosis results

A general approach to determine the optimal set of maintenance alternatives for fatigue safety is introduced in this paper. The optimal maintenance alternatives are the solutions to maximize the fatigue reliability of aircrafts fleet subject to maintenance budget. A novel equivalent stress transformation model and the first-order-reliability method (FORM) are adopted to determine the failure probability or reliability associated with future fatigue loading. The equivalent stress transformation model is capable to transform future random loading to an equivalent constant loading, and does not require cycle-by-cycle simulation. First-order-reliability-method can resolve the computational complexity. Optimal maintenance solution can be efficiently found considering the future fatigue loading. Numerical examples are performed to demonstrate the application of the proposed approach.

SELECTION OF MAINTENANCE STRATEGY FOR AIRCRAFT SYSTEMS USING MULTI-CRITERIA DECISION MAKING METHODOLOGIES

This paper, proposes the Multi-Criteria Decision Making (MCDM) methodology for selection of a maintenance strategy to assure the consistency and effectiveness of maintenance decisions. The methodology is based on an AHP-enhanced TOPSIS, VIKOR and benefit-cost ratio, in which the importance of the effectiveness appraisal criteria of a maintenance strategy is determined by the use of AHP. Furthermore, in the proposed methodology the different maintenance policies are ranked using the benefit-cost ratio, TOPSIS and VIKOR. The method provides a basis for consideration of different priority factors governing decisions, which may include the rate of return, total profit, or lowest investment. When the preference is the rate of return, the benefit-cost ratio is used, and for the total profit TOPSIS is applied. In cases where the decision maker has specific preferences, such as the lowest investment, VIKOR is adopted. The proposed method has been tested through a case study within the aviation context for an aircraft system. It has been found that using the methodology presented in the paper, the relative advantage and disadvantage of each maintenance strategy can be identified in consideration of different aspects, which contributes to the consistent and rationalized justification of the maintenance task selection. The study shows that application of the combined AHP, TOPSIS, and VIKOR methodologies is an applicable and effective way to implement a rigorous approach for identifying the most effective maintenance alternative.

Development of maintenance decision model for flexible pavements

Selection of an appropriate pavement maintenance and rehabilitation (M&R) treatment is often a complex process. Some researchers have suggested a ‘decision tree’ approach to select the most feasible repair strategy based on the existing pavement condition. A decision system, maintenance unit (MU), was developed through research conducted at Cairo University, Egypt. The MU system determines M&R activities based on the density of distress repair methods (not the density of individual distresses). In addition, it addresses the complex combinations between distress levels and maintenance alternatives. Identifying future maintenance needs is an important component for a multi-year analysis. The objective of this study is to develop a maintenance decision model for flexible pavements using data extracted from the long-term pavement performance-DataPave3.0 programme. The proposed model, predicts future MU values with which future maintenance needs are determined. The validation process was performed using different sets of data. This model can play an important role in assisting decision makers in the planning and cost allocation of M&R more effectively.

Multiobjective Optimization Applied to Maintenance Policy for Electrical Networks

A major goal for managers of electric power networks is maximum asset performance. Minimal life cycle cost and maintenance optimization becomes crucial in reaching this goal, while meeting demands from customers and regulators. This necessitates the determination of the optimal balance between preventive and corrective maintenance in order to obtain the lowest total cost. The approach of this paper is to study the problem of balance between preventive and corrective maintenance as a multiobjective optimization problem, with customer interruptions on one hand and the maintenance budget of the network operator on the other. The problem is solved with meta-heuristics developed for the specific problem, in conjunction with an evolutionary particle swarm optimization algorithm. The maintenance optimization is applied in a case study to an urban distribution system in Stockholm, Sweden. Despite a general decreased level of maintenance (lower total maintenance cost), better network performance can be offered to the customers. This is achieved by focusing the preventive maintenance on components with a high potential for improvements. Besides this, this paper displays the value of introducing more maintenance alternatives for every component and choosing the right level of maintenance for the components with respect to network performance.

Pitfalls of HDM-4 strategy analysis

Strategy analysis using the Highway Development and Management Tool (HDM-4) is a powerful means for exercising pavement management planning at the network level. However, since good/bad practices are not well documented, practitioners are often confronted with various pitfalls in conducting strategy analyses using HDM-4. This paper discusses three such pitfalls and proposes remedial guidelines for avoiding them using a case study. They pertain to the generation of good maintenance alternatives, defining appropriate analysis periods of HDM-4 runs in relative to planning periods, and obtaining more or less uniform outlays of investment over the analysis period as benchmarks for strategy analyses. The first problem is particularly acute with the dynamic sectioning approach for the representation of a road network. It is often preferred for its potential accuracy but tends to generate a large number of sections and requires the generation of good alternatives for each of them.

Integration of stochastic deterioration models with multicriteria decision theory for optimizing maintenance of bridge decks

This paper presents a new approach to optimizing the maintenance of concrete bridge decks. This approach combines a stochastic deterioration model and a multiobjective optimization model. The stochastic deterioration model is based on the first-order Markov chain, which predicts the probabilistic time variation of bridge deck conditions. The multiobjective optimization model takes into account two important and conflicting criteria: the minimization of maintenance costs and the maximization of the network condition. This approach achieves the best compromise between these competing criteria while considering the uncertainty in bridge deck deterioration. The feasibility and capability of the proposed approach are demonstrated with field data for a sample network of bridge decks obtained from the Ministère des Transports du Québec database. This example illustrates the effectiveness of the proposed approach in determining the optimal set of maintenance alternatives for reinforced concrete bridge decks when two or more relevant optimization criteria are taken into consideration.Key words: concrete bridge deck, maintenance management, multicriteria optimization, Markov chain, deterioration model.

Maintenance optimization of infrastructure networks using genetic algorithms

This paper presents an approach to determining the optimal set of maintenance alternatives for a network of infrastructure facilities using genetic algorithms. Optimal maintenance alternatives are those solutions that minimize the life-cycle cost of an infrastructure network while fulfilling reliability and functionality requirements over a given planning horizon. Genetic algorithms are applied to maintenance optimization because of their robust search capabilities that resolve the computational complexity of large-size optimization problems. In the proposed approach, Markov-chain models are used for predicting the performance of infrastructure facilities because of their ability to capture the time-dependence and uncertainty of the deterioration process, maintenance operations, and initial condition, as well as their practicality for network level analysis. Data obtained from the Ministére des Transports du Québec database are used to demonstrate the feasibility and capability of the proposed approach in programming the maintenance of concrete bridge decks.

Capturing Effects of Maintenance Practices in Highway Asset Valuation: Replacement-Cost Approach Versus Book-Value Method

The replacement-cost approach and the book-value method as decision support tools for selecting maintenance alternatives under budget constraints and for capturing the effects of maintenance practices on highway asset value are investigated. By using a case study based on the Thailand Pavement Management System, the replacement-cost approach and the book-value method are applied to analyze maintenance alternatives for selected highways. The versatility of these asset-valuation methods is explored for capturing trade-offs in the type and timing of maintenance and for incorporating the added value of effective maintenance practices and the impact of deferred maintenance in the overall asset value. The study demonstrated that the replacement-cost approach is a more versatile tool for considering the maintenance-related value of highways in maintenance decision making, whereas the book value may be a simpler financial accounting tool. The two approaches may be used together to clarify how maintenance expenditures are being translated into facility replacement value or how the overall value of the infrastructure is being preserved. The study results are potentially useful to agencies interested in capturing the added value of effective maintenance practices in the overall value of their asset base.

A multiple-point excitation prediction model of pavement management

In view of the Gray Characteristic of pavements and the variability of pavement performance, a multiple-point excitation prediction model with rear effects on cement concrete pavement performance, GM(1,1, \\delta_{i} ) model, is deduced and established in the light of Gray System Theory. Analysis of the model characteristic is presented. The model parameters of GM(1,1, \\delta_{i} ) are studied and determined, combined with the effects of the maintenance and rehabilitation alternatives. Finally, application to the network level management in P.R.China is presented.

Bridge Maintenance Level Assessment

Parameters in assessing the effectiveness of maintenance tasks on the overall cost of a bridge or system of bridges are identified and the linkage among maintenance, condition rating, and cost is made by subdividing the subjective process into smaller parts. Experience with New York City bridges is used to develop a life expectancy model once the maintenance and repair protocol is specified. Results for several sample maintenance allocations are given to show how a rapid spreadsheet calculation can provide a basis for comparing maintenance alternatives and to point in the direction of an optimized allocation of limited budgets.

MULTIPLE CRITERIA ANALYSIS OF A DWELLING LIFE CYCLE/VIENBUČIŲ GYVENAMŲJŲ NAMŲ GYVAVIMO PROCESO DAUGIAKRITERINĖ ANALIZĖ

The determination of the utility degree and value of the project under investigation and establishment of the priority order for its implementation does not present much difficulty if the criteria numerical values and significances are obtained and the multiple criteria decision-making methods used. The results of the project comparative analysis are presented as a decision-making matrix where columns contain n alternative projects being considered, while all quantitative information pertaining to them is found in lines. Quantitative description of the project provides the information about various aspects of a building life cycle (ie economical, technical, technological, infrastructural, legislative, etc). Quantitative information is based on the criteria systems and subsystems, units of measure, values and initial significances as well as the data on an alternative project. In order to select the best project, it is necessary, having formed the decision-making matrix, to perform the multiple criteria analysis of the projects. This is done by comparing criteria numerical values and significances and analysing the conceptual information of the investigated project. One of the major tasks is to determine the significances of the criteria. This paper presents a new method for complex determination of the criteria significances taking into account their quantitative and qualitative characteristics. When performing multiple criteria assessment of projects it is necessary to normalise the criteria values describing the projects and then to weight them. This creates a possibility to compare the criteria values with different measuring units and to determine the most efficient alternatives. The significances of all criteria must be coordinated among themselves. The method of complex determination of significances allows to determine significances of criteria which are maximally interrelated and depend on qualitative and quantitative characteristics of all criteria. A method of multiple criteria complex proportional evaluation of the projects discussed in this paper assumes direct and proportional dependence of significance and priority of investigated versions on a system of criteria adequately describing the alternatives and on values and significances of the criteria. The system of criteria is determined and the values and initial significances of criteria are calculated by experts. All this information can be corrected by interested parties (customer, users, etc) taking into consideration their pursued goals and existing capabilities. The degree of utility Nj of a building life cycle is directly associated with quantitative and conceptual information related to it. A degree of dwelling life cycle utility reflects the extent to which the goals pursued by the interested parties are attained. The paper concludes with a demonstrative example, concerning the multiple criteria assessment of plot, dwelling, contractor and maintenance alternatives, and dwelling life cycle variants are being developed based on these alternatives of solutions.

Pavement Distress and Selection of Rehabilitation Alternatives: Michigan Practice

The Michigan Department of Transportation (MDOT) practice regarding the preservation, rehabilitation, and preventative maintenance actions for rigid, flexible, and composite pavements is presented and discussed. For each pavement type, the causes of distress and the corresponding MDOT fix alternatives are also presented. Examples of the MDOT practice regarding the selection of maintenance and rehabilitation alternatives for rigid, flexible, and composite pavements are also presented.

Nevada's Approach to Pavement Management

The Nevada Department of Transportation has a fully implemented pavement management system (PMS) at the network level and an extensive pavement evaluation system at the project level. Both systems use actual field performance data that are collected annually from pavement sections throughout the state. The PMS is being further developed to incorporate performance modeling, life-cycle cost analysis, and network optimization processes. Once fully developed the system will allow the engineer to select the best rehabilitation and maintenance alternative that can carry the pavement over the entire analysis period. The project-level evaluation process includes the use of nondestructive testing data and condition surveys from the PMS. The overall systems are summarized at both levels, and the individual steps that are involved within each system are described.

Nevada's Approach to Pavement Management

The Nevada Department of Transportation has a fully implemented pavement management system (PMS) at the network level and an extensive pavement evaluation system at the project level. Both systems use actual field performance data that are collected annually from pavement sections throughout the state. The PMS is being further developed to incorporate performance modeling, life-cycle cost analysis, and network optimization processes. Once fully developed the system will allow the engineer to select the best rehabilitation and maintenance alternative that can carry the pavement over the entire analysis period. The project-level evaluation process includes the use of nondestructive testing data and condition surveys from the PMS. The overall systems are summarized at both levels, and the individual steps that are involved within each system are described.

Reliability and maintainability tradeoff study for repetitive electromagnetic launch systems

A quantitative model has been developed which will support conceptual reliability and maintainability tradeoff studies for repetitive electromagnetic launch systems early in the research and development phase. Model results are presented in a sensitivity analysis format. A study covering a hypothetical 120-shot repetitive launch system was developed, the results of which are displayed in graphical form. Results clearly establish the high degree of effectiveness that modest maintenance alternatives contribute to system availability. In contrast, relatively large improvements in reliability result in modest improvements in availability. Results suggest that system maintainability, as well as reliability, will be a critical issue in electromagnetic launch system development.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Flying Skill Maintenance

A skills maintenance and reacquisition training (Project SMART) research program has been developed to improve Air Force continuation flying training. Project SMART consists of four phases: 1. Preliminary evaluation of research concepts and procedures, 2. Identification and definition of critical flying skills and development of skill measures, 3. Evaluation of skill maintenance and reacquisition training program alternatives, and 4. Measurement of skill retention. The program is sponsored by Air Force Headquarters and is being accomplished by the Air Force Human Resources Laboratory with participation by the Strategic Air Command and the Tactical Air Command. Selected studies completed during Phases 1 and 2 are reported.

Income Maintenance Alternatives and Family: An Analysis of Price Effects

There is some current public concern about the effects of welfare programs on participants' decisions about marriage and divorce or having children. This paper discusses one way in which family composition may be affected by income maintenance program benefits, through what are called effects. After discussing price incentives hypothetically, the paper presents measures of the price incentives in our current welfare system and in the cash component of President Carter's welfare-reform proposal. No income maintenance program can be entirely marriage-neutral, but it is found that the reform generally reduces the destabilizing incentives of the current system.

Assessing Regional Effects of Income Maintenance Programs: A Guide to Policy Analysis

This paper is concerned with research issues that must be faced in assessing the potential subnational effects of proposed income maintenance programs, a job that has barely just begun. The paper is divided into discussions of four major tasks that must be performed by pohcy analysts if they are to help policymakers evaluate these effects. The first of these tasks is simply to list program provisions that may have important subnational effects, either directly or by changing the behavioral patterns of participating families. Examples of spheres of behavior that income maintenance legislation may affect include labor supply, the propensity to migrate, investments in human capital (such as in schooling and on-the-job training), consumption patterns, the propensity to marry and to stay married, and fertihty. The second task is to construct a set of socioeconomic indicators whereby these effects can be gauged in a manner readily comprehensible to policymakers. The third task is to develop an appropriate theoretical framework for analyzing behavioral changes systematically. The fourth task involves obtaining the information necessary to estimate the magnitude of program effects, that is, to predict the changes in the socioeconomic indicators that would result from adoption of the proposed income maintenance alternatives under consideration.