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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Análisis de modos de falla en el proceso de detonación electrónica

Lepileo Soriano, Paola Consuelo January 2012 (has links)
Ingeniera Civil Electricista / El aumento de la inversión extranjera en la industria minera chilena ha generado la necesidad de mejorar los procesos de extracción y tratamiento del mineral, así como de implementar políticas de disminución en sus costos asociados. Inicialmente, dichas políticas se centraron en disminuir los costos en el proceso de tronadura, apuntando mayormente al desarrollo de métodos que permitan conseguir una roca más fragmentada, y por ende, un menor gasto de recursos en el resto del proceso de obtención de mineral. En este sentido, los dispositivos I-Kon, una línea de detonadores electrónicos programables, permiten una asignación de tiempo de detonación para obtener una tronadura mucho más precisa. Debido a la gran cantidad de fallas que se presentan en el proceso de detonación controlado con I-Kon, surge la necesidad de un estudio sobre este proceso. El presente trabajo de título tiene la finalidad de realizar un estudio FMECA (Fault Mode, Effects and Criticality Analysis) para el proceso de detonación impuesto por Orica Chile S.A y controlado por los dispositivos I-Kon en la división Orica Mining Services. Este estudio se realiza en dos de las muchas mineras a las que la empresa presta servicios: Compañía Minera Doña Inés de Collahuasi y Compañía Minera Spence. Para la realización de este estudio se analiza detalladamente el proceso de detonación, identificando los posibles modos de falla, sus causas, nivel de impacto en la operación y sus efectos. Además se lleva a cabo una serie de encuestas a los operadores de los equipos I-Kon, para así obtener información sobre la frecuencia y criticidad de estas fallas. Con estos datos realizan una serie de gráficos que relacionan las fallas provocadas por algún tipo de causa con su criticidad y frecuencia. Como resultado de este estudio se determinan las causas de las fallas más importantes del proceso de detonación, donde cuatro de las seis causas más significativas se asocian directamente a descuidos de los operadores en las distintas etapas del proceso. Para cada causa se sugieren medidas preventivas para evitar la aparición de fallas y en consecuencia, evitar los atrasos que éstas implican para la producción. Se sugiere también, como trabajo futuro, una mejora en los procedimientos de prevención para fallas causadas por problemas de interferencia, las cuales con un estudio más detallado de la correlación entre el campo electromagnético, la humedad del medio y la conductividad del mineral, podrían resultar en nuevas medidas de programación de tronaduras.
2

Management rizik ve výrobě elektromechanických součástek v organizaci Tesla Jihlava, a.s. / Risk management in the production process of the electromechanical components in TESLA Jihlava, a.s.

Přibylová, Zuzana January 2009 (has links)
Risk management is developing branch, which deals with identification, measurement, analysis and regulation of risks in the organisation. The main goal of this work is to find out the most significant risks of the production process in the firm TESLA Jihlava, a.s., to financially evaluate and to minimalize these risks. The way to optimize these risks and to reduce of costs is the mechanisation of the production process in this firm.
3

Reservdelshantering för maskinunderhåll

Abelsson, Ove, Bogdanovic, Dragan January 2011 (has links)
Underhållsavdelningen på Volvo Aero ansvarar för reservdelshanteringen vid köp av nya utrustningar. För att minska tiden för produktionsstopp måste reservdelar finnas tillgängliga på lager när ett behov uppstår. Vid inköpsstadiet erhålls en rekommenderad reservdelslista från maskinleverantören. Erhållen reservdelslista används främst när maskindelar går sönder, för att se vilka möjliga leverantörer som finns. Något arbete med vilka reservdelar som bör finnas tillgängliga utförs inte. Den strategi som används idag är att reservdelar beställs hem efter den erfarenhet som erhålls under maskinens drift. Ett arbetssätt har tagits fram för att hantera den rekommenderade reservdelslistan och därmed öka tillgängligheten i utrustningen och få en bättre ekonomi. Arbetssättet består av fyra steg. Första steget är att se över vilka av de rekommenderade reservdelarna som finns på Volvo Aeros egna förråd. Steg två är att ta fram en ny beställningspunkt för de reservdelar som redan finns på lager förutsatt att förbrukningen kommer att öka. Steg tre är att val om lagerläggning räknas ut matematiskt då livslängden för reservdelen är känd. Steg fyra innebär att feleffektsanalys skall göras för beslut om lagerläggning för reservdelar med icke känd livslängd. I den rekommenderade reservdelslistan ska information som till exempel artikelbenämning, fabrikat, typbeteckning dessutom erhållas om respektive reservdel. Arbetssättet ska tillsammans med informationen från reservdelslistan avgöra om vilka reservdelar som ska lagerläggas. Ett verktyg har också tagits fram för att förenkla arbetssteg ett till fyra. För att verktyget ska kunna användas fullt ut måste maskinleverantören följa Volvo Aeros tekniska specifikation, där det står beskrivet att rekommenderade reservdelar skall anges med en viss data. Data som artikelbenämning, fabrikat och typbeteckning måste finnas i Volvo Aeros system på alla reservdelar som lagrats för att steg ett ska kunna utföras. Den nuvarande tekniska specifikationen bör dessutom kompletteras med uppgifterna om felfrekvens, hur många av reservdelen som finns i maskin och om reservdelen är reparerbar. Dessa uppgifter är en hjälp för att lättare avgöra om reservdelarna skall lagerläggas alternativt köpas vid behov. Arbetssättet och tilläggen i den tekniska specifikationen ska förhoppningsvis leda till ett mer strukturerat arbetssätt och en mer ekonomisk reservdelshantering.
4

Procesní FMECA analýza výroby smrkového lepeného profilu. / Process FMECA of spruce glulam timber production

Janíčková, Bronislava January 2016 (has links)
The thesis is focused on the application of the method FMECA process manufacturing whitewood glued profile. The aim of work is to describe the production, identify fault conditions and their consequences in the fractional sub-processes of production and the analysis of criticality propose measures to increase the reliability of achieving the required quality.
5

Important systems engineering analysis tools : failure mode and effects analysis and hazard analysis

Moore, Alicia Louise Leonard 18 February 2011 (has links)
The goal of every program or project manager is to have a safe reliable product and to have an understanding of the residual risk of operating that product. Two very important systems engineering analysis tools to achieve those objectives are Hazard Analysis and Failure Modes and Effects Analysis. Sometimes seen strictly as Safety and Reliability tasks, these analyses are key to a successful program or project and require input from all stakeholders. When viewed in the Systems Engineering process, Safety and Reliability are truly specialty disciplines within Systems Engineering. Hazard Analysis is used to improve system safety while Failure Modes and Effects Analysis is used to identify ways to increase product reliability; both analyses are required to improve systems design and fully capture the risk for a system or program. Depending on how the analyses are scoped, there could be a perception of overlap and duplication of effort. This paper will present a systems engineering approach to show the need and benefits for performing both types of analyses. Both analysis processes are required to ensure that all possible hazardous conditions and failure modes have been identified and addressed to minimize overall risk to the program/project and to ensure a safe and reliable system. / text
6

Multi criteria risk analysis of a subsea BOP system

Okonji, Stephen Chiedu January 2015 (has links)
The Subsea blowout preventer (BOP) which is latched to a subsea wellhead is one of several barriers in the well to prevent kicks and blowouts and it is the most important and critical equipment, as it becomes the last line of protection against blowout. The BOP system used in Subsea drilling operations is considered a Safety – Critical System, with a high severity consequence following its failure. Following past offshore blowout incidents such as the most recent Macondo in the Gulf of Mexico, there have been investigations, research, and improvements sought for improved understanding of the BOP system and its operation. This informs the need for a systematic re-evaluation of the Subsea BOP system to understand its associated risk and reliability and identify critical areas/aspects/components. Different risk analysis techniques were surveyed and the Failure modes effect and criticality analysis (FMECA) selected to be used to drive the study in this thesis. This is due to it being a simple proven cost effective process that can add value to the understanding of the behaviours and properties of a system, component, software, function or other. The output of the FMECA can be used to inform or support other key engineering tasks such as redesigning, enhanced qualification and testing activity or maintenance for greater inherent reliability and reduced risk potential. This thesis underscores the application of the FMECA technique to critique associated risk of the Subsea BOP system. System Functional diagrams was developed with boundaries defined, a FMECA were carried out and an initial select list of critical component failure modes identified. The limitations surrounding the confidence of the FMECA failure modes ranking outcome based on Risk priority number (RPN) is presented and potential variations in risk interpretation are discussed. The main contribution in this thesis is an innovative framework utilising Multicriteria decision making (MCDA) analysis techniques with consideration of fuzzy interval data is applied to the Subsea BOP system critical failure modes from the FMECA analysis. It utilised nine criticality assessment criteria deduced from expert consultation to obtain a more reliable ranking of failure modes. The MCDA techniques applied includes the technique for order of Preference for similarity to the Ideal Solution (TOPSIS), Fuzzy TOPSIS, TOPSIS with interval data, and Preference Ranking Organization Method for Enrichment of Evaluations (PROMETHEE). The outcome of the Multi-criteria analysis of the BOP system clearly shows failures of the Wellhead connector, LMRP hydraulic connector and Control system related failure as the Top 3 most critical failure with respect to a well control. The critical failure mode and components outcome from the analysis in this thesis is validated using failure data from industry database and a sensitivity analysis carried out. The importance of maintenance, testing and redundancy to the BOP system criticality was established by the sensitivity analysis. The potential for MCDA to be used for more specific analysis of criteria for a technology was demonstrated. Improper maintenance, inspection, testing (functional and pressure) are critical to the BOP system performance and sustenance of a high reliability level. Material selection and performance of components (seals, flanges, packers, bolts, mechanical body housings) relative to use environment and operational conditions is fundamental to avoiding failure mechanisms occurrence. Also worthy of notice is the contribution of personnel and organisations (by way of procedures to robustness and verification structure to ensure standard expected practices/rules are followed) to failures as seen in the root cause discussion. OEMs, operators and drilling contractors to periodically review operation scenarios relative to BOP system product design through the use of a Failure reporting analysis and corrective action system. This can improve design of monitoring systems, informs requirement for re-qualification of technology and/or next generation designs. Operations personnel are to correctly log in failures in these systems, and responsible Authority to ensure root cause analysis is done to uncover underlying issue initiating and driving failures.
7

Determination of Dominant Failure Modes Using Combined Experimental and Statistical Methods and Selection of Best Method to Calculate Degradation Rates

January 2014 (has links)
abstract: This is a two part thesis: Part 1 of this thesis determines the most dominant failure modes of field aged photovoltaic (PV) modules using experimental data and statistical analysis, FMECA (Failure Mode, Effect, and Criticality Analysis). The failure and degradation modes of about 5900 crystalline-Si glass/polymer modules fielded for 6 to 16 years in three different photovoltaic (PV) power plants with different mounting systems under the hot-dry desert climate of Arizona are evaluated. A statistical reliability tool, FMECA that uses Risk Priority Number (RPN) is performed for each PV power plant to determine the dominant failure modes in the modules by means of ranking and prioritizing the modes. This study on PV power plants considers all the failure and degradation modes from both safety and performance perspectives, and thus, comes to the conclusion that solder bond fatigue/failure with/without gridline/metallization contact fatigue/failure is the most dominant failure mode for these module types in the hot-dry desert climate of Arizona. Part 2 of this thesis determines the best method to compute degradation rates of PV modules. Three different PV systems were evaluated to compute degradation rates using four methods and they are: I-V measurement, metered kWh, performance ratio (PR) and performance index (PI). I-V method, being an ideal method for degradation rate computation, were compared to the results from other three methods. The median degradation rates computed from kWh method were within ±0.15% from I-V measured degradation rates (0.9-1.37 %/year of three models). Degradation rates from the PI method were within ±0.05% from the I-V measured rates for two systems but the calculated degradation rate was remarkably different (±1%) from the I-V method for the third system. The degradation rate from the PR method was within ±0.16% from the I-V measured rate for only one system but were remarkably different (±1%) from the I-V measured rate for the other two systems. Thus, it was concluded that metered raw kWh method is the best practical method, after I-V method and PI method (if ground mounted POA insolation and other weather data are available) for degradation computation as this method was found to be fairly accurate, easy, inexpensive, fast and convenient. / Dissertation/Thesis / Masters Thesis Engineering 2014
8

Management rizika produktu

Hykš, Ondřej January 2008 (has links)
Práce pojednává o managementu rizika s důrazem na management rizika produktu. V teoretické části je popsán proces managementu rizika, který je poté v praktické části aplikován na konkrétní výrobek. V procesu managementu rizika produktu je využita metoda FMECA.
9

Použití metody FMECA pro prevenci chyb v průmyslovém podniku / Using of FMECA method for prevention of errors in the industrial enterprise

Macháč, Miroslav January 2012 (has links)
This thesis is focused on using FMECA in a manufacturing company. Analysis was developed in conjunction with a manufacturing company and its main goal is to decrease number of scrap. FMECA helped to find the most critical possible defects and then some actions for decreasing number of scrap were suggested.
10

Procesní FMECA analýza kartonového stojanu / FMECA procedural analysis of a cardboard stand

Potěšilová, Hana January 2015 (has links)
The thesis deals with application of method FMECA to the manufacturing process of cardboard stand. The aim of work is to describe cardboard stand manufacturing, identify fault conditions and their consequences in particular manufacturing processes. In order to increase reliability of cardboard stands, we have designed measures based on analysis of criticality.

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