Through identifying failure manufacturing companies compete in today’s world to gain beneficial attributes. The purpose if this thesis is to develop a model towards identifying failure and the root cause. The model developed to identify failure and the root cause toward it, which should result it decrease in failure time (nonfunction machine). The developed model has tested and analyzed in a manufacturing company. The model has been established through studies based on preventive and predictive maintenance: FMEA & RCA.

<p>More than twenty-five percent of the risk of failure for the 9-1-1 system can be contributed to blocked lines. The second major failure mode is unhelpful or improperly trained telecommunicators. The quick dispatch of emergency response teams in the event of any disaster or accident through the use of the 9-1-1 system is crucial to the well-being of the public. These potential failure modes prevent desperately awaited help from arriving as soon as possible. Therefore, the reliability and effectiveness of the system must be evaluated.</p> <p> The objective of this report is to identify failure modes of the 9-1-1 system, calculate their criticality, prioritize them in order of risk, and propose economical and feasible alternative solutions.</p> <p> Failure mode, effects, and criticality analysis (FMECA) is an evaluation tool that proves extremely useful when a system is desired to be kept highly effective and reliable. In this report, it is applied within the Systems Engineering Process to analyze areas of weakness throughout the New Jersey 9-1-1 system. FMECA is widely used throughout the military and commercial industry. It illustrates the interrelationships between causes and effects of failure modes, and helps to focus attention on high risk areas so that proper precautions may be taken.</p> <p> First, the use of FMECA is reviewed. The step-by-step procedures are next illustrated, and it is noted that FMECA must be tailored to each system relative to its characteristics and desired application. The New Jersey 9-1-1 system is analyzed in detail and is found to be an effective emergency communications network. However, technology has not yet provided solutions to all possible failures. In fact, technology adds to the failure possibilities. Possible future areas of development are included.</p> <p> / Master of Science

In the Swedish railway network there are about 12000 units of track switches and crossings, which at 13000 Km, make up about 5.5 percent of the total track length. However, the maintenance cost for S&amp;C is more than 13 percent of the total maintenance cost which is high in comparison with their proportion. The aim of the project is to conduct research into classification of the different modes of failure in S&amp;C components and to perform a statistical analysis to converge the data in order to determine the most important failures that occur in turnouts.

The grinding rollers of raw mill 7 operate in very harsh conditions and, because of this, suffer from excessive failure mode due to lip seal deterioration. Foreign material penetrates the deteriorated lip seal and enters the bearings resulting in bearing failure. Failure mode brings about high maintenance costs for the cement-producing company Cementa AB. This thesis aims to accomplish two things. 1- Hypothesize a set of root causes for failure mode and link them to existing literature studies to determine what actions should be taken to prevent or at least postpone failure mode. 2- Generate several new conceptual designs for the sealing mechanism by either creating a revolutionary sealing design or taking inspiration from standard seals currently on the market. The generated concepts aim to provide Cementa AB with a new perspective as well as mitigate some or all the root causes for failure mode if implemented. The hypothesized root causes for failure mode are categorized through the creation of a problem tree and are defined as lip seal failure, lubricative pressure and contamination, tribologically improper friction, vibration, and finally very harsh conditions that are indigenous to raw mills in general and that are seemingly incompatible with the current sealing mechanism. Revolutionary concepts are brainstormed entirely from an experimental perspective, while standard concepts are inspired by established sealing technology on the market. Both alternatives are then conceptually adapted to the grinding roller of raw mill 7 and, with inaccurate scaling, 3D modelled with the aid of Autodesk Inventor. 7 concepts, revolutionary and standard combined, are generated as a result. The revolutionary concepts have been deemed non-viable due to the limited timeframe and scope of the thesis. Instead, the selected seal for the upgrade is a labyrinth seal, which is a non-contact standard seal that has the potential to mitigate many of the root causes for failure mode. The literature studies on the hypothesized root causes also indicate that there are actions that could postpone failure mode should Cementa AB chose to retain the original sealing mechanism for a longer period. / Valsarna i råkvarn 7 arbetar under mycket tuffa förhållanden och på grund av detta lider maskinen av en överdriven mängd haverier till följd av läpptätnings försämring. Främmande material tränger igenom den försämrade tätningen och kommer in i lagren vilket resulterar i lagerhaveri. Detta medför höga underhållskostnader för det cementproducerande företaget Cementa AB. Denna avhandling syftar till att åstadkomma två saker. 1-Hypotesera en uppsättning av grundorsaker till lagerhaveri och länka dem till befintliga litteraturstudier för att avgöra vilka åtgärder som kan vidtas för att förhindra eller åtminstone skjuta upp lagerhaveri. 2-Generera flera nya konceptuella konstruktioner för tätningsmekanismen genom att antingen skapa en revolutionerande tätningsdesign eller hämta inspiration från standardtätningar. De genererade koncepten syftar till att ge Cementa AB ett nytt perspektiv såväl som att mildra några eller alla grundorsaker till lagerhaveri om de implementeras. De hypotiserade orsakerna till lagerhaveri kategoriseras genom skapandet av ett problemträd och definieras som trasig läpptätning, smörjningstryck och förorening, tribologiskt felaktig friktion, vibrationer och slutligen tuffa förhållanden som är inhemska för råkvarn generellt. Revolutionära koncept är brainstormade helt ur ett experimentellt perspektiv medan standardkoncept är inspirerade av etablerad tätningsteknik på marknaden. Båda alternativen är sedan konceptuellt anpassade till valsen i råkvarn 7 och, med oegentlig skalning, 3Dmodellerad med hjälp av Autodesk Inventor. 7 koncept, revolutionerande och standard kombinerat, genereras som resultat. De revolutionära koncepten har bedömts vara icke-livskraftiga på grund av avhandlingens begränsade tidsram och omfattning. Istället är den valda tätningen för uppgraderingen en labyrinttätning som är en icke-kontakt standardtätning som har potential att mildra många av orsakerna till lagerhaveri. Litteraturstudierna om de hypotiserade grundorsakerna tyder också på att det finns åtgärder som kan skjuta upp lagerhaveri om Cementa AB väljer att behålla den ursprungliga tätningsmekanismen under en längre period.

Purpose – In the last years companies are challenged by the increasing of innovation, product complexity and customisation, continuous and rapid changes in technology. A company’s successfulness in the market depends on the ability to quickly adapt to changes through innovation and efficiency in its products and services. Risk analysis might lead to success using different tools within the New Product Development (NPD)process, such as Design and Process Failure Mode and Effects Analysis (DFMEA andPFMEA). This study aims to identify how the integration between DFMEA and PFMEA might enhance the co-development of product and production to overcome the challenges in the NPD. To address the purpose, three research questions have been formulated: (1) Are DFMEA and PFMEA linked in the literature and how are they connected? (2) Which are the main challenges and opportunities to integrate DFMEA andPFMEA from a practical point of view? (3) How to improve DFMEA and PFMEAintegration for enhanced co-development of product and production? Method – The research has an inductive approach and data collection was carried out using qualitative methods, such as documents reviews, interviews and workshops. The chosen strategies were a literature review and a case study. Firstly, literature review was conducted in order to identify the connection between DFMEA and PFMEA and feasible methods to integrate them. Thereafter, documentation from two companies and recorded interviews were reviewed to gain information from a practical perspective. Lastly, two workshops were performed to explore further connections between DFEMA and PFMEA by collaborating with the responsible from the two analysed companies. Findings &amp; Analysis – In the literature, three suitable methods that linked DFMEAand PFMEA were identified. After reviewing the documentation from the companies and the recorded interviews and performing two workshops, two different situations were depicted. The companies are implementing different templates and their processes are slightly different. For this reason, a SWOT analysis helped comparing the two companies to identify their challenges and opportunities to integrate DFMEA and PFMEA. The three methods, the comparison between the companies and other reflections helped contribute to the knowledge and improve companies’ processes. Limitations – The main limitation of the study regards time constraints. There are several paths this research can pursue since there was not enough time to further explore in this thesis. In fact, it was intended to find a method to test in the companies and gain results after the test. In the end, the results are suggestions for further research and methods for integrating DFMEA and PFMEA

Yes / The process of generating FMEA following document-centric approach is tedious and susceptible to human error. This paper presents preliminary methodology for robotic manufacturing process modelling in MBSE environment with a scope of automating multiple steps of the modelling process using ontology. This is followed by the reasoning towards automatic generation of process FMEA from the MBSE model. The proposed methodology allows to establish robust and self-synchronising links between process-relevant information, reduce the likelihood of human error, and scale down time expenses.

The development of high power density three-phase ac converter has been a hot topic in power electronics area due to the increasing needs in applications like electric vehicle, aircraft and aerospace, where light weight and/or low volume is usually a must. Many challenges exist due to the complicated correlations in a three-phase power converter system. In addition, with the emerging SiC device technology the operating frequency of the converter can be potentially pushed to the range from tens of kHz to hundreds of kHz at higher voltage and higher power conditions. The extended frequency range brings opportunities to further improve the power density of the converter. Technologies based on existing devices need to be revisited. In this dissertation, a systematic methodology to analyze and design the high power density three-phase ac converter is developed. All the key factors of the converter design are explored from the high density standpoint. Firstly, the criteria for the passive filter selection are derived and the relationship between the switching frequency and the size of the EMI filter is investigated. A function integration concept as well as the physical design approach is proposed. Secondly, a topology evaluation method is presented, which provides the insight into the relationships between the system constraints, operating conditions and design variables. Four topologies are then compared with the proposed approach culminating with a favored topology under the given conditions. Thirdly, a novel average model is developed for the selected topology, and used for devising a carrier-based control approach with simple calculation and good regulation performance. Fourthly, the converter failure mode operation and corresponding protection approaches are discussed and developed. Finally, a 10 kW three-phase ac/ac converter is built with the SiC devices. All the key concepts and ideas developed in this work are implemented in this hardware system and then verified by the experimental results. / Ph. D.

Three-phase voltage source converters(VSCs) have become the converter of choice in many ac medium and high power applications due to their many advantages, including low harmonics, high power factor, and high efficiency. Modular VSCs have also been a popular choice as building blocks to achieve even higher power, primarily through converter paralleling. In addition to high power ratings, paralleling converters can also provide system redundancy through the so-called (N+1) configuration for improved availability, as well as allow easy implementation of converter power management. Interleaving can further improve the benefit of paralleling VSCs by reducing system harmonic currents, which potentially can increase system power density. There are many challenges to implement interleaving in paralleled VSCs system due to the complicated relationships in a three-phase power converter system. In addition, to maximize the benefit of interleaving, current knowledge of symmetric interleaving is not enough. More insightful understanding of this PWM technology is necessary before implement interleaving in a real paralleled VSCs system. In this dissertation, a systematic methodology to analyze and design a paralleled three-phase voltage source converters with interleaving is developed. All the analysis and proposed control methods are investigated with the goal of maximizing the benefit of interleaving based on system requirement. The dissertation is divided into five sections. Firstly, a complete analysis studying the impact of interleaving on harmonic currents in ac and dc side passive components for paralleled VSCs is presented. The analysis performed considers the effects of modulation index, pulse-width-modulation (PWM) schemes, interleaving angle and displacement angle. Based on the analysis the method to optimize interleaving angle is proposed. Secondly, the control methods for the common mode (CM) circulating current of paralleled three-phase VSCs with discontinuous space-vector modulation (DPWM) and interleaving are proposed. With the control methods, DPWM and interleaving, which is a desirable combination, but not considered possible, can be implemented together. In addition, the total flux of integrated inter-phase inductor to limit circulating current can be minimized. Thirdly, a 15 kW three phase ac-dc rectifier is built with SiC devices. With the technologies presented in this dissertation, the specific power density can be pushed more than 2kW/lb. Fourthly, the converter system with low switching frequency is studied. Special issues such as beat phenomenon and system unbalance due to non-triplen carrier ratio is explained and solved by control methods. Other than that, an improved asymmetric space vector modulation is proposed, which can significantly reduce output current total harmonic distortion (THD) for single and interleaved VSCs system. Finally, the method to protect a system with paralleled VSCs under the occurrence of internal faults is studied. After the internal fault is detected and isolated, the paralleled VSCs system can continue work. So system reliability can be increased. / Ph. D.

Yes / Risk Management is one of the most relevant approaches and systematic application of strategies, procedures and practices management that have been introduced in literature to identifying and analysing risks which exist through the whole life of a product or a process. As a quality management tool, the novelty of this paper suggests a modified Failure Modes and Effect Analysis (FMEA) for understanding the non-technical risk comprehensively, and to attain a systemic methodology by decomposing the risk for nine risk categories including an appropriate 84 Risk Indicators (RI's) within all those categories through the Life Cycle (LC) stages of power plants. These risk categories have been identified as: economic risks, environmental and safety health risks, social risks, technological risks, customer/demand risks, supply chain risks, internal and operational business process risks, human resources risks and management risks. These indicators are collected from literatures. The enhanced FMEA has combined the exponential and the weighted geometric mean (WGM) to calculate the Exponential Weighted Geometric Mean-RPN (EWGM-RPN). The EWGM-RPN can be used to evaluate the risk level, after which the high-risk areas can be determined. Subsequently, effective actions either preventive or corrective can be taken in time to reduce the risk to an acceptable level. However, in this paper the FMEA will not adapt an action plan. Due to that, all RPN's will be considered depending on the point scale (1 to 5) afterward, the results will be combined and extended later with AHP. This developed methodology is able to boost effective decision- making about risks, improve the awareness towards the risk management at power plants, and assist the top management to have an acceptable and preferable understanding of the organisation than lower level managers do who are close to the day-to-day (tactical plan). Additionally, this will support the organisation to develop strategic plans which are for long term. And the essential part of applying this methodology is the economic benefit. Also, this paper includes developed sustainability perspective indicators with a new fourth pillar, which is the technological dimension. The results of the analysis show that the potential strategic makers should pay special attention to the environmental and internal and operational business process risks. The developed methodology will be applied and validated for different power plants in the Middle East. An expanded validation is required to completely prove drawbacks and benefits after completing the Analytical Hierarchy Process (AHP) model. / Hashemite University, Jordan

A influência de variáveis metodológicas no valor da resistência de união e no padrão de fratura, por ensaio de microcisalhamento, foi verificada em dentina planificada de molares humanos e estudada em quatro diferentes experimentos, nos quais dois sistemas adesivos foram utilizados (Adper Single Bond 2 e XP Bond) e uma resina composta (Filtek Z250). Foram eles: Experimento 1- momento de fotoativação do adesivo: antes ou após o posicionamento das cânulas sobre o substrato dentinário; Experimento 2- tempo de armazenagem: 10min, 24 horas, 48 horas e 7 dias em água destilada a 37oC; Experimento 3- área de secção transversal dos corpos de prova: 0,44mm2, 0,82mm2, 1,98mm2 e 4,44mm2; Experimento 4- momento de fotoativação da resina / remoção da cânula para o ensaio. Os dados obtidos de resistência de união, em MPa, foram tratados por métodos de ANOVA. Os corpos de prova resultantes de todos os experimentos foram observados em microscopia eletrônica de varredura e analisados de forma qualitativa quanto ao modo de fratura. Houve diferença significativa no Experimento 1, sendo que os valores médios de resistência de união foram mais altos quando os adesivos foram fotoativados antes de posicionar as cânulas. Não houve diferença estatisticamente significante para as variáveis tempo de armazenagem e sistema adesivo (Experimento 2), e nem para as variáveis área de secção transversal e sistema adesivo estudadas (Experimento 3). Para o Experimento 4, houve diferença estatisticamente significante para a condição experimental resina fotoativada e remoção da cânula quando previamente realizada à adesão ao substrato e entre os adesivos. Em todos os experimentos o modo de fratura foi predominantemente adesivo/misto. Concluiu-se que algumas variáveis do método são fundamentais para sua padronização, pois com base nos resultados deste estudo elas influenciam os valores médios da resistência de união. / The effect of methodological variables on the microshear bond strength and fracture pattern was assessed in flat human molars dentin in four different experiments using two adhesive systems (Adper Single Bond 2 and XP Bond) and a composite resin (Filtek Z250). The experiments were: 1. Adhesive light activation moment prior or after mold positioning on dentin; 2. Storage period 10 min, 24h, 48h or 7 days in distilled water at 37oC; 3. Mold transversal section area 0.44mm2, 0.82mm2, 1.98mm2 and 4.44mm2; 4. Resin light activation moment with or without mold removal prior to testing. Mean data values (MPa) were subjected to ANOVAs methods. All fractured specimens were qualitatively analyzed in SEM to verify the fracture mode. Regarding Experiment 1 a significative difference was shown for the main factor Adhesive Light Activation Moment; higher bond strength values were achieved with adhesive system ligth activated before mold positioning. No significant differences were found for storage period or section area analyzed on Experiments 2 and 3, respectively. The main factor Resin Light Activation Moment presented differences when the resin composite was previously light activated and mold was removed prior to bonding the resin with the adhesive systems. In all experiments, mode of failure was predominantly adhesive/mixed. The conclusion is that some variables of the method are essential for its standardization, given that they influence the bond strength values.