A Multi-Stage Remanufacturing Approach for Life Extension of Safety Critical systems

Life extension of safety critical systems is gaining popularity in many industries due to the increasing demand in world's energy consumption and the strong desire to reduce carbon emissions by different countries. Identification and implementation of a suitable life extension strategy enables safety critical systems to perform their intended functions under stated condition for an extended period of time beyond original design life. In the past, the viability analysis of life extension strategies has been undertaken based on the accumulated knowledge and experience of Original Equipment Manufacturer (OEM), maintenance engineers and inspectors. These approaches involving expert judgement are qualitative in nature and based on conservative assumptions, which may lead to inaccurate conclusion or misleading recommendations to asset managers. Therefore, it is crucial to develop an approach consisting of methods to determine the technical condition of components, estimate the cost of life extension interventions and to analyze carbon footprints. “Remanufacturing” is considered as a suitable end-of-life strategy that can help reduce the overall environmental burden from the product by processing waste materials while at the same time keeping reliability high. Due to the advantages of remanufacturing, it is widely applied for life extension purposes in safety critical industries such as offshore oil and gas, nuclear power, petrochemical, renewable energy, rail transport, aviation, shipping, and electricity distribution and transmission. In this paper, a multi-stage approach is presented to analyze the impact of remanufacturing of safety critical systems on the performance of industrial operations in terms of total cost and carbon footprint. In this approach, the equipment health status is determined by modelling the degradation of the system and then the maintenance costs and carbon footprint are calculated. For the purpose of clarity, the proposed model is applied to an air compressor system and the results are discussed

Analysis of the environmental impact on remanufacturing wind turbines

To deliver clean energy the use of wind turbines is essential. In June 2011 there was an installed wind capacity equivalent to 211,000MW world-wide (WWEA, 2011). By the end of the year 2009 the U.S. had 35,100MW of wind energy installed capacity to generate electricity (AWEA, 2010). This industry has grown in recent years and is expected to grow even more in the future. The environmental impacts that will arise from the increased number of wind turbines and their end-of-life should be addressed, as large amounts of resources will be required to satisfy the current and future market demands for wind turbines. Since future 10MW wind turbines are expected to be as heavy as 1000 tons each, the study of the environmental response of profitable retirement strategies, such as remanufacturing for these machines, must be considered. Because of the increased number of wind turbines and the materials used, this study provides a comparison between the environmental impacts from remanufacturing the components installed inside the nacelle of multi-megawatt wind turbines and wind turbines manufactured using new components. The study methodology is the following: * Describe the life-cycle and the materials and processes employed for the manufacture and remanufacturing for components inside the nacelle. * Identify remanufacturing alternatives for the components inside the nacelle at the end of the expected life-time service of wind turbines. * Evaluate the environmental impacts from the remanufactured components and compare the results with the impacts of the manufacturing of new components using SimaPro. * Conduct sensitivity analysis over the critical parameters of the life cycle assessment * Propose the most environmentally friendly options for the retirement of each major component of wind turbines. After an analysis of the scenarios the goal of the study is to evaluate remanufacturing as an end-of-life option from an environmental perspective for commercial multi-megawatt wind turbines targeted for secondary wind turbine markets

Circular economy business models and technology management strategies in the wind industry: Sustainability potential, industrial challenges and opportunities

Circular business models, aimed at narrowing, slowing, and closing resource loops, can potentially generate significant economic and social benefits, promote resource security and improve environmental performance. However, within the wind power industry, sustainability research, including life cycle assessments, has been focused mostly on technology innovation at the material (e.g. permanent magnets), components (e.g. blades) or product level (e.g. new assets). Research analysing the implementation of circular business models in the wind industry is scarce. Such information could, however, support more robust decision-making in the development of system-level innovations for the deployment of more resource-efficient and sustainable wind energy infrastructure. Building upon practical methods for the identification, categorisation and characterisation of business models, 14 circular business models with application to the wind industry were comprehensively evaluated through the revision of 125 documents, including 56 journal papers, 46 industrial business cases and 23 wind technology management reports. Each circular business model is examined according to i) business offering and drivers, ii) value creation, delivery and capture mechanisms, iii) sustainability benefits and trade-offs, and iv) industrial challenges and opportunities. Accordingly, comprehensive guidelines to drive political (legislation design and implementation), industrial (technology and business innovation) and academic (further research) actions, are provided. Though the results are focussed on the wind industry, the general findings and recommendations are relevant across the renewable and low-carbon energy sector

Feasibility analysis of design for remanufacturing in bearing using hybrid fuzzy-topsis and taguchi optimization

The tremendous advancement in technology, productivity and improved standard of living has come at the cost of environmental deterioration, increased energy and raw material consumption. In this regard, remanufacturing is viable option to reduce energy usage, carbon footprint and raw material usage. In this manuscript, using computational intelligence techniques we try to determine the feasibility of remanufacturing in case of roller bearings. We collected used N308 bearings from 5 different Indian cities. Using Fuzzy-TOPSIS, we found that the roundness, surface roughness and weight play a vital role in design for remanufacturing of roller bearings. Change in diameter, change in thickness and change in width showed minimal influence.  We also used Taguchi analysis to reassess the problem. The roundness of inner and outer race was found to be the most influential parameters in deciding the selection of bearing for remanufacturing. The results suggest the bearing designer to design the bearing in such a way that roundness of both races will be taken cared while manufacturing a bearing. However, using Taguchi the weight of the rollers was found to be of least influence. Overall, the predictions of Taguchi analysis were found to be similar to Fuzzy-TOPSIS analysis

Product-service system inventory control: manufacturing perspectives

This thesis explores the role of Inventory Control in Product Service System (PSS) applications within manufacturing contexts. This research led to a new approach for dealing with inventory control and contributes to understanding of the PSS paradigm in manufacturing industries. PSS embraces the product and service continuum as one system; meanwhile, Inventory Control has led to substantial improvements in performance across many industries. PSS and Inventory Control have for many years been recognized in the scientific literature and by industry as enablers of manufacturing operations. Most studies in the field of PSS and Inventory Control have only focussed on its individual scenarios; little is known about where the boundaries of PSS should lie as it needs to integrate both external and internal elements in managing PSS Inventory Control. To date, very little research has been reported related to inventory control in product-service systems from manufacturing operations perspectives. Research has been done in three stages: (1) PSS characteristics were synthesised from the literature; (2) current industry example of PSS inventory were investigated through a survey; four case studies were developed; (3) uncertainty elements were identified from the literature related to the current PSS Inventory Control scenario and these were evaluated, developed and validated producing a generic model. The research carried out involved collecting primary data from qualitative research conducted through four case studies with companies in the United Kingdom and Malaysia; and information from secondary sources; utilising techniques such as survey, interview, matrix and modelling language method. This thesis contributes to the current PSS research by developing a generic model of PSS Inventory Control from manufacturing operations perspectives and a PSS Inventory Control (PSSIC) Framework

Performance improvement of remanufacturing systems operating under N-policy

This thesis deals with N-policy M/G/1 queueing remanufacturing system with general server breakdown and start-up time, where the value of returned products exponentially deteriorates since received. The server will instantly turn on the system, but the system requires a start-up period to prepare for remanufacturing when returned products in the queue reach the value of N. Otherwise, the system keeps in turn-off status. During the remanufacturing process, the machines may break down and will return back to service immediately after repairing. The procedures that will be used to achieve the target are as follows. Firstly, the expression of cost function will be derived and solved. Next, the simulation software ProModel will be used to simulate this problem. Finally, a sensitivity analysis is used on a numerical example to show the applicability of the methodology and quality of results

Towards a simulation-based understanding of smart remanufacturing operations : a comparative analysis

While the majority of literature on remanufacturing operations examines an end-of-life (EOL) strategy which is both manual and mechanised, authors generally agree that digitalisation of remanufacturing is expected to increase in the next decade. Subsequently, a new research area described as digitally-enabled remanufacturing, remanufacturing 4.0 or smart remanufacturing is emerging. This is an automated, data-driven system of remanufacturing by means of Industry 4.0 (I4.0) paradigms. Insights into smart remanufacturing can be provided through simulation modelling of the remanufacturing process. While the use of simulation modelling in order to predict responses and behaviour is prevalent in remanufacturing, the use of these tools in smart remanufacturing is still limited in literature. The goal of this research is to present, as a first of its kind, a comparative understanding of simulation modelling in remanufacturing in order to suggest the ideal modelling tool for smart remanufacturing. The proposed comparison includes system dynamics, discrete event simulation and agent based modelling techniques. We apply these modelling techniques on a smart remanufacturing space of a sensor-enabled product and use assumptions derived from industry experts. We then proceed to model the remanufacturing operation from sorting and inspection of cores to final inspection of the remanufactured product. Through our analysis of the assumptions utilised and simulation modelling results we conclude that, while individual modelling techniques present important strategic and operational insights, their individual use may not be sufficient to offer comprehensive knowledge to remanufacturers due to the challenge of data complexity that smart remanufacturing offers

Reliability-Informed Life-Cycle Warranty Cost Analysis: A Case Study on a Transmission in Agricultural Equipment

In agricultural and industrial equipment, both new and remanufactured systems are often available for warranty coverage. In such cases, it may be challenging for equipment manufacturers to properly trade-off between the system reliability and the cost associated with a replacement option (e.g., replace with a new or remanufactured system). To address this problem, we present a reliability-informed life-cycle warranty cost (LCWC) analysis framework that enables equipment manufacturers to evaluate different warranty policies. These warranty policies differ in whether a new or remanufactured system is used for replacement in the case of product failure. The novelty of this LCWC analysis framework lies in its ability to incorporate real-world field reliability data into warranty policy assessment using probabilistic warranty cost models that consider multiple life cycles. First, the reliability functions for the new and remanufactured systems are built as the time-to-failure distributions that provide the best-fit to the field reliability data. Then, these reliability functions and their corresponding warranty policies are used to build the LCWC models according to the specific warranty terms. Finally, Monte Carlo simulation is used to propagate the time-to-failure uncertainty of each system, modeled by its reliability function, through each LCWC model to produce a probability distribution of the LCWC. The effectiveness of the proposed reliability-informed LCWC analysis framework is demonstrated with a real-world case study on a transmission used in some agricultural equipment