Thesis (Ph.D.)--University of Tulsa, 1994. / Includes bibliographical references (leaves 87-92).

Orientador: Celso Kazuyuki Morooka / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-23T20:08:04Z (GMT). No. of bitstreams: 1 Mendes_JoseRicardoPelaquim_M.pdf: 6979997 bytes, checksum: cb7b7cacbcb91fb76e57ca2cad3585fc (MD5) Previous issue date: 1998 / Resumo: Uma série de trabalhos desenvolvidos com o uso do conceito de Sistemas Inteligentes Distribuídos, criando agentes de raciocínio fornecido por especialistas em diversas áreas do Petróleo, implementadas em um shell específico (Kards), tem vislumbrado um grande potencial do uso desta tecnologia no ramo do Petróleo. Na seleção de brocas para a perfuração de poços de Petróleo, o objetivo é alcançar um mínimo custo métrico, sendo a seleção na prática realizada através de poços de correlação e na própria experiência do engenheiro de perfuração. O uso de métodos analíticos geralmente necessitam de informações expendiosas além de ser uma tarefa árdua devido a complexibilidade do problema. Nesta dissertação é apresentado um método de preservação do conhecimento especializado no processo de seleção de brocas tricônicas através de redes neurais, lógica nebulosa e ferramentas disponíveis no Sistema Kards. Este trabalho serviu de base para arquitetar um Sistema Inteligente para o auxílio de seleção de brocas tricônicas, sendo útil também em termos de treinamento de novos engenheiros / Abstract: A series of works developed using the concept of Distributed Intelligent Systems, creating agents of reasoning provided by experts in several areas of Petroleum, structured in a specific shell (Kards), has glimpsed a great potencial of this technology in Petroleum sector. ln the bit selection to drill oil well, the objective is to obtain a minimum metric cost, being the selection in practice realized using correlation wells and in drilling engineers experience. The use of analytical methods usually needs extensive informations and moreover it is hard job owing to complexity of the problem. ln the thesis is presented a method of preservations of specialized knowledge jn triconics drills selection process using neural nets, fuzzy logic and available tools in the Kards System. This work was a base to construct an lntelligent System for the assistance of triconics drills selection, being also useful to fit to training of engineers / Mestrado / Mestre em Engenharia de Petróleo

published_or_final_version / abstract / Applied Geosciences / Master / Master of Science

No description available.

Este trabalho apresenta um estudo a respeito do comportamento do solo durante a escavação de um túnel, com foco na metodologia de escavação mecanizada. São abordadas diretrizes para a modelagem numérica de túneis com o emprego de diferentes métodos de cálculo, distintos modelos constitutivos para representação do comportamento do solo e duas maneiras de se representar o revestimento da escavação. Alguns conceitos fundamentais relacionados a escavações de túneis de grande diâmetro em solo com o emprego de máquinas tuneladoras são descritos, como os tipos de máquinas existentes (com ênfase nas máquinas do tipo EPB - Earth Pressure Balance), princípios de funcionamento e modos de operação, além de uma comparação deste método com a metodologia sequêncial tradicional. É realizada uma revisão bibliográfica sobre distintos métodos de cálculo para estimar a estabilidade de uma escavação, a previsão da deformação no maciço e os esforços atuantes no revestimento do túnel. O trabalho também apresenta uma revisão de publicações recentes a respeito da modelagem numérica de túneis escavados mecanicamente, destacando algumas diferenças em relação à metodologia sequencial. Uma das diferenças é com relação à simulação do revestimento do túnel, com a possibilidade de se considerar as propriedades das juntas dos anéis. Outro ponto distinto é o método de cálculo empregado, levando em conta na simulação aspectos específicos da escavação mecanizada, como pressão de frente aplicada, vazio anelar e injeção de grout. É feita uma breve introdução e são apresentados os conceitos básicos de dois modelos constitutivos do solo: o modelo elastoplástico perfeito conhecido como Mohr-Coulomb e o modelo elastoplástico com endurecimento Hardening Soil. Utilizando alguns dos conceitos estudados na revisão bibliográfica, são realizadas análises numéricas bidimensionais retroanalisando um caso real de escavação com tuneladora. Foi utilizado o programa de elementos finitos Plaxis para realizar comparações entre os métodos de cálculo do alívio de tensões e da contração, além da simulação do revestimento com ou sem a consideração das juntas. Por fim é feita uma análise crítica dos resultados obtidos nas diferentes modelagens numéricas. / This research presents a study about the soil behavior during the excavation of a tunnel, focusing on the mechanized excavation methodology. Guidelines for the numerical modeling of tunnels with the use of different calculation methods, distinct constitutive models to characterize the soil behavior and two ways of representing the lining of the excavation are addressed. Relevant aspects regarding excavations of large diameter tunnels in soil with the use of TBM (Tunnel Boring Machine) are presented, like types of machines, with the focus on the Earth Pressure Balance (EPB) machines, fundamental concepts of the methodology and operation modes, besides a comparison of this method with the traditional sequential methodology. A literature review on different methods of calculation to estimate the excavation stability, the prediction of ground deformation and the efforts acting in the tunnel lining is made. The research also presents a review of recent publications regarding numerical modeling of mechanically excavated tunnels, highlighting some differences with the sequential method. One of these differences is related to the simulation of the tunnel lining, with the possibility of considering the properties of the ring joints. Another different point is the calculation method employed, considering in the simulation specific aspects of mechanized excavation, as front pressure applied, ring void and grout injection. A brief introduction is made about constitutive models to represent the soil behavior and the basic concepts of two constitutive soil models are presented: Mohr-Coulomb and Hardening Soil. Using some of the concepts studied in the literature review, it is performed two-dimensional numerical analysis with a back-analysis of a real case, using the finite element model program Plaxis, comparing the calculation methods of stress relieving and contraction, as well as the tunnel lining simulation with or without consideration of the joints. Finally, it is made a critical analysis of the results of the numerical simulations.

Improvement of manufacturing productivity is dependent on the successful automation of manufacturing processes, the success of which is based in turn upon the availability of information which describes the state of manufacturing operations. Acoustic Emission (AE) signals related to the cutting process and tool wear have been recently applied to monitor manufacturing processes, and various AE parameters can be used to provide process information. For example, when cutting tools become worn, AE energy generated at the interface of tool flank and work piece increases. This study is thus an experimental investigation of the AE spectrums representing AE signals energy distribution to determine the possibility of extracting useful parameters to provide on-line information about drilled-hole quality and drill-bit wear. An experiment conducted using a radial-arm drilling machine was employed to collect on-line AE drilling process spectrums, yielding eight indicator parameters. Drill wear states were measured using a machine vision system. Assessment of the drilled hole quality was based on tolerances established in Geometric Dimensioning and Tolerancing (GD&T). Correlations among drill wear, drilled-hole quality measurements, and the AE spectrum indicator parameters were examined by regression analysis. A forward-stepwise variable selection procedure was used to select the best-fit regression model for each drilled hole quality measurement associated with the set of one AE parameter raised to different powers. According to quality measurements, drilled holes were categorized as either "acceptable" or "unacceptable" holes, using cluster analysis with a group-averaging method. The usage of AE parameters to decide to which group a drilled hole belonged was also examined. From the experimental evidence, it was observed that there are strong relationships between AE parameters and drill-wear state and the quality measurements of drilled holes. AE parameters could be useful predictor variables to provide information to controller/operators to evaluate current drilling processes. Based on the status information of drill wear and the quality measurements, drilling processes can be adjusted accordingly. / Graduation date: 1997

In the aerospace industry, burr removal is a very important part of the manufacturing process. Stacks of material on sections of an aircraft are assembled and drilled by hand. Due to extensive burr formation the sheets must be destacked so that burrs can be removed and then the stacks are reassembled and fastened together. If burrs are minimized in the drilling process, this would reduce the necessity for the sheets to be destacked and deburred. One approach to minimizing burrs is to lower the thrust force in drilling through suitable modification of the drill geometry such as the use of a step drill. Although prior researchers have analyzed different drill geometries such as step drills and their effect on hole exit burr formation in the drilling process through experimentation, no work has been reported on modeling and analysis of step drilling forces and their relationship to burr formation as a function of the step drill geometry parameters. Consequently, this thesis focuses on the modeling of the thrust force and torque for step drills and analyzes their relationship with burr size as a function of the step drill geometry parameters. In the first step, a mechanistic model for thrust and torque in drilling is implemented for a standard twist drill. This mechanistic model is then adapted to predict the thrust and torque for a step drill. Subsequently, experiments are performed to validate the mechanistic model and to evaluate burr formation with standard and step drills. The influence of thrust and torque on hole exit burr formation is analyzed for different step drill geometries and experimental feeds and speeds. The results show that the predicted thrust and torque values for both drill geometries are in good agreement with measured values, although the torque model consistently underpredicts. For standard drill geometry in the calibration tests, the average error in the thrust prediction is 7.09% and the average error in the torque prediction is -18.05%. In validation tests, the average error for predicted thrust is 2.29% and the average error for predicted torque is -18.46%. For the step drill model the average error in thrust is 0.72% while the average error in torque is -8.72%. In addition, a reduction in the predicted thrust force for a step drill relative to the standard twist drill is found to correlate well with a reduction in the measured burr size. However, further reduction in the thrust force by varying the step angle and diameter ratio do not correlate well with the measured burr size. Likely reasons for these results are presented in this thesis.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 230-235). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 230-235). Also available on the Internet.

Thesis (M.A.)--York University, 2001. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 142-161). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ71710.