This work investigates the feasibility of developing a self-powered structural health monitoring (SHM) smart tire using piezoelectric materials. While this work is divided into two components: SHM and energy harvesting, the context of smart tire in this work is defined as the development of a SHM system that (i) has self-powering capabilities, and (ii) addresses the potential of embedding sensors. The use of impedance based SHM on a tire is severely limited due to the low stiffness and high damping characteristics of the tire. This work propose the use of a high voltage impedance analyzer, and the addition of electrical circuit to enhance the damage detection process. Experimental work was conducted on an aluminum beam and on a tire section with commercially available piezoelectric sensors. The use of a high voltage impedance analyzer was demonstrated to provide insight on damage type and damage location. Two sensors were connected in parallel as an effective sensory system, and was shown to reduce interrogation time, but reduce damage identification sensitivity. With added electrical circuits, a belt separation on the tire was successfully detected by the shift in electrical impedance signature. For the energy harvesting portion of this work, a bimorph piezoelectric energy harvester model was derived using extended Hamilton's principle and the linear constitutive relations of piezoelectric materials. Comparison of model with experimental data at increasing loading conditions demonstrated the monotonic increase in voltage output, with linear asymptotes at extreme loading conditions (short-circuit and open-circuit). It also demonstrated the existence of an optimal resistive load for maximum power output. To address the ability to embed sensors, an existing fabrication process to grow arrays of ZnO nanowires in carbon fiber reinforced polymer was used in this work. Comparison of power generation from a composite beam with ZnO nanowires with a composite beam without ZnO nanowires demonstrated the power generation capabilities of the nanowires. A maximum peak voltage of 8.91 mV and peak power of 33.3 pW was obtained. After the application of 10V DC, a maximum of 45 pW was obtained. However, subsequent application of 20V DC reduced the maximum peak power output to 2.5 pW. Several attempts to increase power generation including adding a tip mass and changing the geometry of the composite beam were conducted. Finally, the theoretical voltage frequency response function obtained from the theoretical piezoelectric constant and dielectric constant of a single ZnO nanowire were compared to the experimental voltage frequency response function. The discrepancies were discussed. / Master of Science

This study was conducted at the Virginia Tech Power Plant to measure and compare stack emissions while firing coal alone and coal mixed with shredded tires. The coal-tire mixtures consisted of 10 and 20 percent tire chips. Modified EPA method 5 sampling train was used to determine particulate emissions. CO emissions were determined with an ENERAC 2000 gas analyzer. Supelco XAD-2 resin was used in the modified method 5 sampling train to adsorb nonpolar, vapor phase hydrocarbons. The XAD-2 resin was extracted and the wash concentrated before High Performance Liquid Chromatography (HPLC) was used to quantify the presence of benzene, chrysene, phenol, and benzo(a)pyrene. Particulate emissions resulting from the combustion of 0, 10 and 20 percent tire mixtures with coal were 0.88, 2.32, and 2.13 lb/10⁶ Btu, respectively. For carbon monoxide, the emissions were 0.17,0.22, and 0.33 1b/10⁶ BTU for 0, 10, and 20 percent tire mixtures, respectively. Large variations in polynuclear aromatic hydrocarbon (PAH) emissions were observed. Therefore, only trends in the PAH data can be discussed. Phenol emissions appeared to increase with the addition of shredded tires to the combustion process. Benzene and benzo(a)pyrene emissions appeared to decrease with the addition of shredded tires to the combustion process. An increase in chrysene emissions for 20% addition of shredded tires was observed. A larger data base is needed in order to develop stronger conclusions regarding PAH emissions resulting from coal/tire shred combustion in a conventional spreader stroker. / Master of Science

In recent years, composite materials have been widely used in several applications due to their superior mechanical properties including high strength, high stiffness, and low density. Despite the remarkable advancements in theoretical and computational methods for analyzing composites, investigating the effect of lamina properties and lay-up configurations on the strength of composites still remains an active field of research. Finite Element Method (FEM) and Extended Finite Element Method (XFEM) are powerful tools for solving the boundary value problems. One of the objectives of this work is to employ XFEM as a defect identification tool for predicting the crack initiation and propagation in composites. Another major objective of this study is to investigate the damage development in hyperelastic materials. Two Finite Element models are adopted to study this phenomenon: multiscale modeling of the cord-rubber composites in tires and modeling of intelligent tires for evaluating the feasibility of the proposed defect detection technique. A new three-dimensional finite element approach based on the multiscale progressive failure analysis is employed to provide the theoretical predictions for damage development in the cord-rubber composites in tires. This new three-dimensional model of the cord-rubber composite is proposed to predict the different types of damage including matrix cracking, delamination, and fiber failure based on the micro-scale analysis. This process is iterative and data is shared between the finite element and multiscale progressive failure analysis. It is shown that the proposed cord-rubber composite model solves the problems corresponding to embedding the rebar elements to the solid elements and also increases the fidelity of numerical analysis of composite parts since the laminate characteristic variables are determined from the microscopic parameters. A tire rolling analysis is then conducted to evaluate the effects of different variables corresponding to the cord-rubber composite on the performance of tires. Tires operate on the principle of safe life and are the only parts of the vehicle which are in contact with the road surface. Establishing a computational method for defect detection in tire structures will help manufacturers to fix and develop more reliable tire designs. A Finite Element model of a tire with a tri-axial accelerometer attached to its inner-liner was developed and the effects of changing the normal load, longitudinal velocity and tire-road contact friction on the acceleration signal were investigated. Additionally, using the model, the acceleration signals obtained from several accelerometers placed in different locations around the inner-liner of the intelligent tire were analyzed and the defected areas were successfully identified. Using the new intelligent tire model, the lengths, locations, and the minimum number of accelerometers in damage detection in tires are determined. Comparing the acceleration signals obtained from the damaged and original tire models results in detecting defects in tire structures. / PHD / In recent years, composite materials have been widely used in several applications due to their superior mechanical properties. Studying the effect of different configurations and thicknesses on the strength of composites still remains an active field of research. Finite Element Method (FEM) is a powerful tool for simulating real problems. One of the objectives of this work is to employ FEM to show the damage development in the composite and rubber-based materials. Two Finite Element models are adopted to study this phenomenon: multiscale modeling of the cord-rubber composites in tires and modeling of intelligent tires, which are tires with sensors attached to the inner-liner, for evaluating the feasibility of the proposed defect detection technique. A new three-dimensional finite element approach based on the multiscale progressive failure analysis is employed to provide the theoretical predictions for damage development in the cord-rubber composites in tires. This new three-dimensional model of the cord-rubber composite is proposed to predict the different types of damage based on the micro-scale analysis. This process goes through the damage prediction formulations in each step to check whether damage happened or not. If damage happened, the stiffness of materials will be decreased. The fidelity of analysis is increased since the macro-scale mechanical properties are calculated based on the micro-scale properties. A tire rolling analysis is then conducted to evaluate the effects of different variables corresponding to the cord-rubber composite on the performance of tires. Tires operate on the principle of safe life and are the only parts of the vehicle which are in contact with the road surface. Establishing a computational method for defect detection in tire structures will help manufacturers to fix and develop more reliable tire designs. A tire with a sensor attached to its inner-liner was developed and the effects of changing the normal load, velocity and tire-road contact friction on the acceleration signal were investigated. Additionally, using the model, the acceleration signals obtained from several sensors placed in different locations around the inner-liner of the tire were analyzed. The defected areas were successfully identified by comparing the acceleration signals obtained from the damaged and original tire models.

Este trabalho tem como objetivo o desenvolvimento de uma tecnologia para a atenuação do impacto provocado pelo passivo ambiental gerado por pneus inservíveis, conjuntamente ao desenvolvimento de novos materiais compostos para uso na construção.Os pneus têm uma estrutura física especial, com grande resistência e durabilidade, mesmo ao término de sua vida útil e, por isso, sua deposição em aterros sanitários é inadequada, já que eles não permitem compactação, tornando-se favoráveis para a criação de agentes causadores de enfermidades e oferecem grandes riscos de incêndios, o que acarreta sérios danos ao meio ambiente. A tecnologia desenvolvida utilizou a borracha de pneus inservíveis, após serem picados por processo mecânico, segundo diferentes tamanhos, para a composição de produtos de baixo custo e utilizáveis na construção civil em elementos construtivos, placas de amortecimento sonoro e de revestimento de pisos para edificações, sinalização horizontal em vias públicas, absorvedores de impacto em estradas,etc. O agente de aglomeração utilizado foi a resina poliuretânica derivada do óleo de mamona (Ricinus communis), uma fonte renovável, que também apresenta estabilidade física e química, e um excelente desempenho como aglomerante. O composto obtido foi testado com relação à durabilidade, às propriedades mecânicas como resistência à compressão e tração, módulo de elasticidade e fluência por meio da termo análise, demonstrando resultados satisfatórios e confirmada sua aplicação em vários campos da construção civil. / The objective of this work is to develop a technology for the impact attenuation caused by the passive environmental generated by scrap tires, jointly to the development of new composites for being used in construction. The tires have a special physical structure, with great resistance and durability, also in the term of their useful life, therefore, their deposit in landing fields are inadequate, once they do not allow compacting, becoming favorable for the creation of causes of diseases and they offer great fires risks, what causes serious damages to the environment. The developed technology used the rubber of useless tires, after being fragmented by mechanic process, according to different sizes, for the composition of products of low cost to be used in the civil construction in constructive elements, noise reduction plates and lining of floors for constructions, horizontal signaling in public ways, impact insulating in highways, and so on. The agent of mass used was the polyurethane resin, derived of the castor oil (Ricinus communis), a renewable source that also presents physical and chemical stability, and a good bonding behavior. The obtained composite was tested in relation to durability behavior, mechanical properties which the compression forces and tension, and also its modulus of elasticity and creep by use of thermo analisys, demonstrated satisfactory results and confirmed its application in a many fields of the civil construction.

O objetivo do presente trabalho é avaliar o uso de borracha triturada de pneu como carburante substituto do coque após a fusão e durante o refino primário oxidante em um forno elétrico a arco na produção de aço 1020. Para o teste foram produzidas 40 toneladas de borracha de pneu triturado em condições granulométricas semelhantes ao coque e abastecido nos silos que alimentam injetoras que adicionaram este material durante o refino primário oxidante. No sistema existem 3 silos e 3 injetoras que são capazes de operar com vazões independentes. O silo n° 1 e o silo n° 3 foram abastecidos com borracha triturada, enquanto que o silo n° 2 foi abastecido com o coque. Testou-se durante 152 corridas situações com injeção de borracha em 4 níveis como substituto do coque: 0% de borracha (somente coque), 33% de borracha, 66% de borracha e 100% de borracha. As vazões e quantidades totais injetadas de carburante foram mantidas em relação ao processo usual. Para evitar interferências manteve-se a receita de carga fria metálica para abastecer o forno bem como os programas elétricos e químicos. Em todas as corridas testadas foram coletadas amostras do aço e da escória no momento antes do vazamento. As amostras foram analisadas através de um espectrômetro de RX. Os resultados obtidos mostraram que é possível a substituição total do coque pela borracha de pneu triturada sem incorrer prejuízos ao processo. Não se observou incorporação de Enxofre no aço, preocupação esta que existia pelo fato da borracha triturada conter teores mais elevados deste elemento em comparação com o coque. / The purpose of this research is to evaluate the use of grinded wasted rubber tires as a carbon source to substitute the coke during the refine in an Electric Arc Furnace to produce steel - grade 1020. For the tests, it was produced 40 tons of grinded rubber in similar size grains of the coke and the material was filled up inside the tanks that feeds the carbon injectors and added the carbon source during the primary oxidant refine. The system is composed by 3 tanks and 3 injectors that can be operate independent. The tank number 1 and number 3 were filled up with grinded rubber, and the tank number 2 was filled up with coke. It was tested during 152 heats 4 different levels of rubber injection to substitute coke: 0% of rubber, 33% of rubber, 66% of rubber and 100% rubber. The flow and injected quantities were kept in the same levels of the normal process. The metallic raw material and electrical and chemical profile were kept the same to avoid interferences. Samples of the steel and the slag were taken before the tap. The samples were analyzed in the RX Spectrometer. The results showed that is it possible to substitute completely the coke with rubber without causing any issues to process. The sulfur content in the rubber did not contaminated the steel, although the rubber contains higher sulfur compared to the coke.

[pt] Há mais de um século a humanidade usufrui de um invento essencial ao desempenho, economia e conforto à rodagem de veículos: o pneu. Entretanto, o pneu tem uma vida útil limitada, caracterizada pela redução de suas ranhuras - até o limite que comprometa a estabilidade do veículo. Uma vez ultrapassada a vida útil, sobra uma carcaça, constituída por materiais de alta resistência e toxicidade, que vem sendo, simplesmente, descartada e lançada à natureza. Em conseqüência, o pneu é considerado hoje um dos maiores problemas ambientais do mundo. Além de demorar até 600 anos para se decompor, um pneu pode causar diversos malefícios para a sociedade e o meio ambiente, quando dispostos inadequadamente. É nesse contexto que a logística reversa pós-consumo vem se desenvolvendo, ou seja, estudando maneiras de como um produto descartado pela sociedade pode retornar ao ciclo de negócios. Este trabalho apresenta um estudo do problema logístico reverso na reciclagem industrial por pirólise com xisto de pneus. O objeto de estudo será o programa Paraná Rodando Limpo, um projeto desenvolvido no estado do Paraná, que coleta e recicla pneus descartados. Além de descrever os agentes envolvidos, traçar e caracterizar a rede reversa desde a captação, transporte e reciclagem dos pneus, um estudo de otimização de rotas foi proposto para tornar o processo mais eficiente. / [en] For more than a century, the world civilization has benefited from an invention to essential the performance, cost reduction, and comfort of vehicles: the tire. However, the tire has a limited useful life, characterized by the reduction of its grooves, up to a limit that jeopardizes the stability of the vehicle. Once such useful life is exceeded, a carcass constituted by high- resistance and toxicity materials is discharged and thrown away in the environment. As a consequence, today the tire is considered one of the largest environmental problems in the world. It takes more than 600 years for a tire to decompose, resulting, when not properly disposed, in several problems to the society and its environment. In this context the post-consumption reverse logistics is being developed, namely, studying ways for a product that has been discarded by the society returning to the business cycle. This work presents a study of a reverse logistics problem in the industrial recycling of tires by pyrolysis with shale. The object of study will be the Parana Rodando Limpo project (Parana running in a clean way) developed by the State of Parana, which is in charge of collecting and recycling tires that are discharged. The study describes all the involved agents, outlines and characterizes the reverse logistics flows including the collection, the transport and the recycling of the tires and, in addition, proposes a routing optimization study in order to improve the efficiency of the process.

A presente pesquisa teve como objetivo a avaliação do uso da banda de rodagem de pneus inservíveis triturada (BPIT) como suporte ao desenvolvimento de biofilmes em um reator anaeróbio de leito expansível (RALEx), em escala plena, com volume de 32m3, empregado no tratamento de esgoto sanitário. A utilização desse material como suporte apresentou-se como proposta inovadora, com grande potencial de aplicação. Para partida do sistema foram utilizados 6,0m3 de lodo proveniente do reator UASB da Estação de Tratamento de Esgoto Jardim das Flores de Rio Claro – SP, tendo sido alcançado o equilíbrio dinâmico aparente após 80 dias de operação. A BPIT mostrou-se eficiente como recheio do RALEx, tendo em vista que promoveu remoção média de 70% de matéria orgânica, em termos de DBO (amostras não filtradas), quando operado com tempo de detenção hidráulico médio de 3,2h, velocidade ascensional média de 5,7m/h (sem recirculação do efluente), e carga orgânica volumétrica média de 5,4kgDQO/m3.dia. A remoção média de sólidos em suspensão no sistema foi de 65% (com teor residual no efluente de 95mg/L) e a porcentagem de metano no biogás manteve-se próxima a 65%. Assim como os demais reatores anaeróbios, verificou-se que a remoção de nitrogênio e fósforo no RALEx foi relativamente baixa, com valores inferiores a 10%. Avaliou-se também a perda de carga no leito de BPIT, obtendo-se valores extremamente baixos para todas as granulometrias testadas, em torno de 4cm/m de leito, e determinou-se a velocidade mínima de fluidificação em 39m/h. Nos ensaios preliminares, verificou-se que o diâmetro equivalente das partículas de BPIT foi de 4,3mm, com coeficiente de desuniformidade de 1,61 e massa específica de 1,14g/cm3. A BPIT mostrou-se competitiva também no aspecto econômico, tendo em vista que o custo de aquisição foi 12,8 vezes inferior ao do carvão ativado granular e 1,6 vezes superior ao da areia (materiais comumente utilizados como recheio de RALEx). / The present research had as objective the assessment of granulated tread of scrap tires (GTST) as support for the development of biofilms in an expanded bed anaerobic reactor (EBAR), in full scale, with a total volume of 32m3, employed for wastewater treatment. The use of this material as support was presented as an innovating proposal, with a high application potential. To start up the system 6.0m3 of sludge coming from the UASB reactor from Jardim das Flores Wastewater Treatment Plant, Rio Claro – SP, were used. The apparent dynamic equilibrium was reached 80 days after operating start up. GTST showed itself as efficient in the packing of the EBAR, where it removed an average of 70% of organic matter, in terms of BOD (non-filtered samples), when operated with hydraulic detention time of 3.2h, mean ascension velocity of 5.7m/h (without effluent re-circulation), and mean volumetric organic load of 5.4kgCOD/m3.day. The mean suspended solids removal in the system was of 65% (with 95mg/L of residual content in the effluent) and the percent of methane in biogas was close to 65%. Likewise in other anaerobic reactors, it was seen that nitrogen and phosphorous removal in the EBAR was relatively low, with values below 10%. Headloss was also assessed in the bed of the GTST, where extremely low values were obtained for all tested granulometry, around 4cm/m in the bed. In the preliminary essays, it was verified that the equivalent diameter of GTST particles was of 4.3mm, with disuniformity coefficient of 1.61 and specific mass of 1.14g/cm3. GTST was also competitive in the economical aspect, where the acquisition cost was 12.8 times lower than granular activated carbon and 1.6 times higher than sand (materials commonly used as EBAR packing material).

O principal objetivo desta pesquisa é determinar o custo operacional e o ponto de renovação da frota de tratores agrícolas de pneus de uma empresa agropecuária, utilizando-se os dados dos dispêndios do uso de 39 tratores, entre os anos de 1983 e 1998. Aplicou-se o método do custo anualizado equivalente (CAE), pelo qual é possível determinar-se a idade de substituição dos tratores, a partir do custo operacional e do fluxo de caixa de cada trator. A análise dos resultados obtidos permitiu concluir que dentre os custos operacionais as despesas com reparos e manutenção são as mais elevadas o que pode ser atribuído às altas horas de trabalho acumuladas, tornando antieconômica a utilização da máquina na empresa. Os valores calculados através do custo anualizado equivalente (CAE), apresentaram resultados maiores que os calculados pelo custo operacional. A diferença fundamental entre os dois métodos de cálculo está no CAE que considera uma remuneração ao capital utilizando a taxa de desconto do fluxo de caixa. O método do custo anualizado equivalente, mostrou-se eficiente na análise da vida econômica de tratores e na determinação do ponto de substituição de frotas, pois permite a substituição da máquina antes que ocorram as despesas mais altas com a mesma. Caso contrário, a perda de capital provocada pela diminuição do valor presente do valor residual, calculado pelo CAE, pode inviabilizar o uso econômico da máquina. Verificou-se com a aplicação do CAE que a idade de substituição de uma máquina depende do valor de inicial, das despesas anuais com o trator, de valor de revenda em cada ano e da taxa de desconto. Especificamente para esta empresa verificou-se que a idade economicamente ótima de troca situou-se entre quatro e cinco anos de vida útil do trator. / The main objective of the present study was to determine the operational cost and the fleet renewal point of agricultural tractors of tires for an agricultural company, which provided data on expenditures for the use of 39 tractors, from 1983 to 1998. The computation took in account the yearly cost equivalent method (CAE), which allowed to determine the tractor substitution age , starting from the operational cost and from the cash flow of each tractor. The analysis results analysis showed that the greater item in the operational costs is the expenses with repairs and maintenance which can be attributed to the greater accumulated working hours, so far it may make not profitable the use of the machine in the company. The CAE method values showed bigger values than the operational cost method values (OC). The fundamental difference among them is that CAE considers a remuneration to the capital using the cash flow discount tax. Also , the CAE method was more efficient in the analysis of the tractor economical life and in the determination of the fleet substitution point, so it allowed the substitution of the machine before higher expenses might occur. Otherwise, the capital loss provoked by the decrease of the present value of the residual value, computed by CAE, would make unfeasible the economical use of the machine. Also ,the present study showed that the age of substitution of a machine depends on the initial value, on the annual expenses with the tractor, on the value of resale in every year and on the discount tax. Specifically for this company, it was verified that the economical age to change a vehicle is between four or five years of useful life of the tractor.

Made available in DSpace on 2017-07-21T20:42:34Z (GMT). No. of bitstreams: 1 Armando Madalosso Vieira Filho.pdf: 12599724 bytes, checksum: 65d627ecd808a90acce0c965752d8655 (MD5) Previous issue date: 2009-09-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Finding new ways and techniques of recycling has been one of the main paths searched by investigators to solve the problem of the garbage. For this study were chosen two of the polymers with large volumes of post-consumer material: LDPE and rubber tire. Several studies have been made to incorporate rubber tire in polymers by following different paths one of them is the devulcanization of rubber tire by microwave. The focus of this study was process and characterize blends of virgin and / or recycled LDPE with ground tire rubber. Both formulations, virgin and recycled LDPE, were made with percentage by weight of 0, 5, 10, 20 and 40 of rubber in and with percentage by weight of 0 and 10 in the blends of 50% virgin / 50% recycled LDPE. The formulations were processed into a of single screw extruder, granulated, injected and treated with microwave “in situ”. Tests were made for size distribution of the rubber, tensile, bending, optical and scanning electron microscopy, DSC and infrared spectroscopy. As results obtained were: a rubber tire can be used as an additive for staining, mechanical properties similar to almost all formulations was obtained with up to 10% of tire rubber. The amount of rubber incorporated and composition (recycled or virgin) influence the mechanical and thermal properties of some blends. The treatment with microwaves "in situ" presented influence on the mechanical and thermal properties in the formulations tested, presenting differential properties, such as increased maximum stress in some formulations, demonstrating that the study of the treatment is technologically interesting. / Encontrar novos meios e técnicas de reciclagem têm sido um dos grandes caminhos buscados por pesquisadores para resolver o problema do lixo. Para este estudo foram escolhidos dois dos polímeros com grandes volumes de material pós-consumo: PEBD e borracha de pneu. Várias pesquisas têm sido feitas no sentido de incorporar borracha de pneu em polímeros seguindo diversos caminhos e dentre eles está a desvulcanização da borracha por microondas. O objetivo deste trabalho foi processar e caracterizar misturas de PEBD virgem e/ou recicladas incorporadas com pó de borracha de pneu. Foram feitas formulações com teores de 0, 5, 10, 20 e 40% em peso de borracha no PEBD virgem e reciclado, e 0 e 10% em blendas de PEBD/ PEBD reciclado (50/50). As formulações foram processadas em extrusora de rosca simples, injetadas e tratadas com microondas “in situ”. Foram feitos ensaios de distribuição granulométrica da borracha, tração, flexão, microscopia, DSC e FTIR. Observou-se: que a borracha de pneu pode servir como aditivo para fins de coloração; propriedades mecânicas similares com até 10% de borracha para quase todas as formulações; que a quantidade de borracha incorporada e o tipo de matriz influenciam as propriedades mecânicas e térmicas. O tratamento “in situ” com microondas apresentou influência nas propriedades mecânicas e térmicas nas formulações ensaiadas apresentando propriedades diferenciadas, como aumento da tensão máxima em algumas formulações, demonstrando que o estudo do tratamento é interessante tecnologicamente.

Resumo: O desempenho operacional dos tratores agrícolas é dependente da interação dos rodados e a superfície de contato, sendo de extrema importância a seleção do tipo de pneu, pressão de inflação e lastragem para as diversas operações agrícolas, proporcionando maior eficiência de tração e menor compactação do solo, racionalizando assim, os custos operacionais do sistema produtivo. O presente trabalho teve como objetivo avaliar e correlacionar as metodologias de determinação das áreas de contato e deformações elásticas de pneus agrícolas em superfícies rígida e deformável, em função das pressões de inflação e das cargas radiais, com a finalidade de identificar a metodologia mais acurada e prática para cada condição de ensaio estático de pneus. O experimento foi realizado no Núcleo de Ensaio de Máquinas e Pneus Agrícolas (NEMPA) da Faculdade de Ciências Agronômicas - UNESP, Câmpus de Botucatu, SP. Os pneus estudados foram do tipo R1 com as seguintes dimensões: pneu baixa pressão e alta flutuação (500/60-26.5) inflado com as pressões de 206,7 kPa, 103,3 kPa e 68,9 kPa; radial (14.9R26) com pressões de inflação de 186,1 kPa, 137,8 kPa e 68,9 kPa e diagonal (14.9-26) com pressões de 206,7 kPa, 137,8 kPa e 68,9 kPa; submetidos as cargas de 5 kN, 10 kN, 15 kN e 20 kN aplicadas por uma prensa hidráulica. As áreas de contato dos pneus agrícolas em superfície deformável foram obtidas em tanque de solo e em superfície rígida pelo método do pó, carbono e massa. Os valores das áreas de contato foram determinados por duas metodologias de cálculo: equação da elipse e digitalização das áreas. Os resultados permitiram concluir que a metodologia de cálculo das áreas de contato através da equação da elipse é confiável e prática para obter as áreas de contato dos pneus agrícolas... / Abstract: The agricultural tractor performance is depended of interaction among the tire and contact surface, and then, the selection of tire type, its inflation pressure and tractor ballast are very important to several conditions of agricultural operation, proportioning higher efficiency of machines and lower soil compaction, rationalizing the operations costs of crop systems. This present research had for main objective the evaluation and correlation of methodologies of tire/ground contact areas and elastic deformations of agricultural tires on rigid and deformable surfaces, in function of inflation pressures and ballasts, identifying the methodology most accuracy and practice for each condition of tire static test. The research was carried out at Agricultural Machinery and Tire Testing Center (NEMPA), Rural Engineering Department of Agronomic Science College, Sao Paulo State University (UNESP), Botucatu/SP, Brazil. The studied tires were of R1 type with the following dimensions: low pressure and high fluctuation tire (500/60-26.5) inflated with pressures of 206,7 kPa, 103,3 kPa and 68,9 kPa; radial ply (14.9R26) with inflation pressures of 186,1 kPa, 137,8 kPa and 68,9 kPa and bias ply (14.9-26) with pressures of 206,7 kPa, 137,8 kPa and 68,9 kPa. Four ballast conditions were applied on the wheels by hydraulic press: 5 kN, 10 kN, 15 kN and 20 kN. The contact areas of the agricultural tires on deformable surface were obtained in soil bin and on rigid surface by powder, carbon paper and modelling mass methods. The contact area values were determined by two calculus methodologies: ellipse equation and areas digitalization. The results of methodologies used to calculate the contact areas permit to conclude that ellipse equation can estimate with precision and practice the contact areas of agricultural tires... / Orientador: Kléber Pereira Lanças / Coorientador: Reginaldo Barboza da Silva / Banca: Afonso Lopes / Banca: Marcos Milan / Mestre