A Simulation Based Approach for Determining Maintenance Strategies

Manufacturing organizations are continuously in the mode of identifying and implementing mechanisms to achieve a competitive edge. To this point manufacturers have recognized the critical role of equipment in the productivity of manufacturing operations. With the current trend of manufacturers attempting to lean out their production processes, primary and auxiliary equipment have become even more important to manufacturers as measured by productivity, quality, delivery, and cost metrics. As a result of the focus on lean manufacturing, maintenance management has found a new vigor and purpose to increase equipment capacity and capability. However, the most proactive maintenance strategy is not always the most effective utilization of resources. It is typical for manufacturers to integrate both reactive and proactive maintenance to define a cost effective maintenance strategy. A simulation-based approach is presented that allows an end user to develop such a maintenance strategy

A system-approach for recoverable spare parts management using the discreteweibull distribution

Optimal spare parts management strategies allow sustaining a system's availability, while ensuring timely and effective maintenance. Following a systemic perspective, this paper starts from the Multi-Echelon Technique for Recoverable Item Control (METRIC) to investigate the potential use of a Weibull distribution for modelling items' demand in case of failure. Adapting the analytic formulation of METRIC through a Discrete Weibull distribution, this study originally proposes a METRIC-based model (DW-METRIC) to be used for modelling the stochastic demand in multi-item systems, in order to ensure process sustainability. The DW-METRIC has been tested in a case study related to an industrial plant constituted by 98 items in a passive redundancy configuration. Comparing the results via a simulation model, the outcomes of the study allow defining applicability criteria for the DW-METRIC, in those settings where the DW-METRIC offers more accurate estimations than the traditional METRIC

Wind Power Performance Optimization Considering Redundancy and Opportunistic Maintenance

In This paper the redundancy and imperfect opportunistic maintenance optimization of a multi-state weighted k-out-of-n system is formulated. The objective is to determine the k-out-of-n system redundancy level and the maintenance strategy which will minimize the wind farm life cycle cost subject to an availability constraint. A new condition based opportunistic maintenance approach is developed. Different component health state thresholds are introduced for imperfect maintenance of failed subsystems and working subsystems and preventive dispatching of maintenance teams. In addition, a simulation method is developed to evaluate the performance measures of the system considering different types of subsystems, maintenance activation delays and durations, limited number of maintenance teams, and discrete inspection of the system. Also, a multi-seed tabu search heuristic algorithm is also proposed to solve the formulated problem. An application to the optimal design of a wind farm is provided to illustrate the proposed approach

Risk based life management of offshore structures and equipment

Risk based approaches are gaining currency as industry looks for rational, efficient and flexible approaches to managing their structures and equipment. When applied to inspection and maintenance of industrial assets, risk based approaches differ from other approaches mainly in their assessment of failure in its wider context and ramifications. These advanced techniques provide more insight into the causes and avoidance of structural failure and competing risks, as well as the resources needed to manage them. Measuring risk is a challenge that is being met with state of the art technology, skills, knowledge and experience. The thesis presents risk based approaches to solving two specific types of problem in the management of offshore structures and equipments. The first type is finding the optimum timing of an asset life management action such that financial benefit is maximised, considering the cost of the action and the risk (quantified in monetary terms) of not undertaking that action. The approach presented here is applied to managing remedial action in offshore wind farms and specifically to corroded wind turbine tower structures. The second type of problem is how to optimise resources using risk based criteria for managing competing demands. The approach presented here is applied to stocking spares in the shipping sector, where the cost of holding spares is balanced against the risk of failing to meet demands for spares. Risk is the leitmotiv running through this thesis. The approaches discussed here will find application in a variety of situations where competing risks are being managed within constraints

In-flight maintenance study Final report

Sample system analysis, MF requirements, redesign, and packaging desig

After-Sales Service Contracting for Excellence in Life-Cycle Cost Management: Numerical Experiments and Systematic Review of Analytical Models

This research adds to the literature and provides insight to practice via three essays that increase understanding about the applications and consequences of the two new approaches to the after-sales service governance: warranty contract and performance-based contracts. First, we attempted to enhance our knowledge of the modeling of the after-sales service process. In the first essay, the research papers with analytical models of after-sales services to present current trends, issues, and future research directions in the literature are classified. In the second essay, the effect of the warranty contract on the supplier's product quality improvement efforts in the context of capital goods is examined. Three sets of optimization models reveal that the existence of a warranty improves product quality. In the third essay, the performance-based contract is examined in the context of the warranty contract. The numerical experimentations conducted demonstrate that the performance-based contract is superior to the warranty contract in terms of the supplier's product quality efforts and the customer's total cost of after-sales services. The alignment of incentives based on the product performance tackles the issues presented in the traditional after-sales service contracting. Collectively, the three studies presented in this research expand our understanding of after-sales service contracts. Thus, the research presents managerial implications and adds to the existing body of knowledge in after-sales service research

A Collection of Technical Papers

Papers presented at the 6th Space Logistics Symposium covered such areas as: The International Space Station; The Hubble Space Telescope; Launch site computer simulation; Integrated logistics support; The Baikonur Cosmodrome; Probabalistic tools for high confidence repair; A simple space station rescue vehicle; Integrated Traffic Model for the International Space Station; Packaging the maintenance shop; Leading edge software support; Storage information management system; Consolidated maintenance inventory logistics planning; Operation concepts for a single stage to orbit vehicle; Mission architecture for human lunar exploration; Logistics of a lunar based solar power satellite scenario; Just in time in space; NASA acquisitions/logistics; Effective transition management; Shuttle logistics; and Revitalized space operations through total quality control management