Cerca de 60% do total de cargas transportadas no país, utilizam-se do modal rodoviário, ainda que apenas 13,5% das estradas do país sejam pavimentadas, e, destas 48% possuam algum tipo de deficiência. Inseridas neste contexto, estão as quase 1300 fabricantes de implementos rodoviários, veículos destinados especificamente ao transporte dessas cargas. O cenário evidencia a concorrência existente neste segmento. Para manterem-se competitivas, estas empresas devem oferecer produtos com maior qualidade, durabilidade, segurança e a um custo competitivo. Uma das etapas do desenvolvimento que mais consome recursos destas empresas são as avaliações de durabilidade dos seus respectivos produtos e, neste intuito, as ferramentas de simulação numérica são importantes aliadas, pois permitem estimar a vida em fadiga dos mesmos ainda na fase de concepção, reduzindo custos em garantias, protótipos e tempo despendido no desenvolvimento de um novo produto. A vida em fadiga dos componentes e estruturas metálicas pode ser definida através de duas principais abordagens: domínio do tempo ou domínio da frequência, também chamado de métodos espectrais. Esta abordagem apresenta tanto excitações quanto respostas em termos de Densidade Espectral de Potência - PSD, enquanto a abordagem no domínio do tempo apresenta excitações e respostas em termos de históricos temporais. O uso de métodos espectrais possui como vantagens a redução do esforço computacional, melhor entendimento do comportamento dinâmico da estrutura, além de permitir a análise de trechos representativos das pistas por onde o implemento trafega. O presente trabalho apresenta uma metodologia para estimativa da vida em fadiga de componentes de implementos rodoviários, além de um estudo de caso, utilizando métodos espectrais. A solução do problema faz uso de acelerações aquisitadas em pistas de asfalto e estrada de chão e estes valores são utilizados como dados de entrada na estimativa da vida em fadiga do componente em estudo. Efeitos das tensões médias e critérios de multiaxialidade também foram abordados. / About 60% of the total cargo transported in the country makes use of highways, however only 13.5% of the country's roads are paved, and 48% of them have some type of disability. Inserted in this context there are approximately 1300 manufacturers of road implements, vehicles designed specifically to the transport of cargo. The scenario highlights the competition in this segment. In order to remain competitive, that companies must offer products with higher quality, durability, safety and lower cost. One of development the stages that consumes more resources from these companies is the durability evaluation of their products and, in this aim, numerical simulation tools are important allies, as they allow to estimate the fatigue life of them, still in the design phase, reducing costs in guarantees, prototypes and the time spent in the development of a new product. The fatigue life of components and metallic structures can be defined by two main approaches: the time domain and the frequency domain or spectral method. This spectral approach has both excitations and responses in terms of the Power Spectral Density - PSD, while the time domain approach involves the excitations and responses in terms of some history of time. The use of spectral methods have the advantage of reducing the computational effort, a better understanding of the dynamic behavior of the structure, and allows the analysis of more representative sections of tracks where the implement travels. This work uses one specific methodology for fatigue life assessment of components of road implements, besides a study of some particular case, using spectral methods. The solution of the problem makes use of experimental accelerations measured in paved and unpaved roads, where they are used as input data in the fatigue life assessment of the component in study. Mean stress effects and multiaxial stresses criteria were also considered.

abstract: Composite materials are widely used in various structural applications, including within the automotive and aerospace industries. Unidirectional composite layups have replaced other materials such as metals due to composites’ high strength-to-weight ratio and durability. Finite-element (FE) models are actively being developed to model response of composite systems subjected to a variety of loads including impact loads. These FE models rely on an array of measured material properties as input for accuracy. This work focuses on an orthotropic plasticity constitutive model that has three components – deformation, damage and failure. The model relies on the material properties of the composite such as Young’s modulus, Poisson’s ratio, stress-strain curves in the principal and off-axis material directions, etc. This thesis focuses on two areas important to the development of the FE model – tabbing of the test specimens and data processing of the tests used to generate the required stress-strain curves. A comparative study has been performed on three candidate adhesives using double lap-shear testing to determine their effectiveness in composite specimen tabbing. These tests determined the 3M DP460 epoxy performs best in shear. The Loctite Superglue with 80% the ultimate stress of the 3M DP460 epoxy is acceptable when test specimens have to be ready for testing within a few hours. JB KwikWeld is not suitable for tabbing. In addition, the Experimental Data Processing (EDP) program has been improved for use in post-processing raw data from composites test. EDP has improved to allow for complete processing with the implementation of new weighted least squares smoothing options, curve averaging techniques, and new functionality for data manipulation. / Dissertation/Thesis / Masters Thesis Civil Engineering 2016

Cerca de 60% do total de cargas transportadas no país, utilizam-se do modal rodoviário, ainda que apenas 13,5% das estradas do país sejam pavimentadas, e, destas 48% possuam algum tipo de deficiência. Inseridas neste contexto, estão as quase 1300 fabricantes de implementos rodoviários, veículos destinados especificamente ao transporte dessas cargas. O cenário evidencia a concorrência existente neste segmento. Para manterem-se competitivas, estas empresas devem oferecer produtos com maior qualidade, durabilidade, segurança e a um custo competitivo. Uma das etapas do desenvolvimento que mais consome recursos destas empresas são as avaliações de durabilidade dos seus respectivos produtos e, neste intuito, as ferramentas de simulação numérica são importantes aliadas, pois permitem estimar a vida em fadiga dos mesmos ainda na fase de concepção, reduzindo custos em garantias, protótipos e tempo despendido no desenvolvimento de um novo produto. A vida em fadiga dos componentes e estruturas metálicas pode ser definida através de duas principais abordagens: domínio do tempo ou domínio da frequência, também chamado de métodos espectrais. Esta abordagem apresenta tanto excitações quanto respostas em termos de Densidade Espectral de Potência - PSD, enquanto a abordagem no domínio do tempo apresenta excitações e respostas em termos de históricos temporais. O uso de métodos espectrais possui como vantagens a redução do esforço computacional, melhor entendimento do comportamento dinâmico da estrutura, além de permitir a análise de trechos representativos das pistas por onde o implemento trafega. O presente trabalho apresenta uma metodologia para estimativa da vida em fadiga de componentes de implementos rodoviários, além de um estudo de caso, utilizando métodos espectrais. A solução do problema faz uso de acelerações aquisitadas em pistas de asfalto e estrada de chão e estes valores são utilizados como dados de entrada na estimativa da vida em fadiga do componente em estudo. Efeitos das tensões médias e critérios de multiaxialidade também foram abordados. / About 60% of the total cargo transported in the country makes use of highways, however only 13.5% of the country's roads are paved, and 48% of them have some type of disability. Inserted in this context there are approximately 1300 manufacturers of road implements, vehicles designed specifically to the transport of cargo. The scenario highlights the competition in this segment. In order to remain competitive, that companies must offer products with higher quality, durability, safety and lower cost. One of development the stages that consumes more resources from these companies is the durability evaluation of their products and, in this aim, numerical simulation tools are important allies, as they allow to estimate the fatigue life of them, still in the design phase, reducing costs in guarantees, prototypes and the time spent in the development of a new product. The fatigue life of components and metallic structures can be defined by two main approaches: the time domain and the frequency domain or spectral method. This spectral approach has both excitations and responses in terms of the Power Spectral Density - PSD, while the time domain approach involves the excitations and responses in terms of some history of time. The use of spectral methods have the advantage of reducing the computational effort, a better understanding of the dynamic behavior of the structure, and allows the analysis of more representative sections of tracks where the implement travels. This work uses one specific methodology for fatigue life assessment of components of road implements, besides a study of some particular case, using spectral methods. The solution of the problem makes use of experimental accelerations measured in paved and unpaved roads, where they are used as input data in the fatigue life assessment of the component in study. Mean stress effects and multiaxial stresses criteria were also considered.

Cerca de 60% do total de cargas transportadas no país, utilizam-se do modal rodoviário, ainda que apenas 13,5% das estradas do país sejam pavimentadas, e, destas 48% possuam algum tipo de deficiência. Inseridas neste contexto, estão as quase 1300 fabricantes de implementos rodoviários, veículos destinados especificamente ao transporte dessas cargas. O cenário evidencia a concorrência existente neste segmento. Para manterem-se competitivas, estas empresas devem oferecer produtos com maior qualidade, durabilidade, segurança e a um custo competitivo. Uma das etapas do desenvolvimento que mais consome recursos destas empresas são as avaliações de durabilidade dos seus respectivos produtos e, neste intuito, as ferramentas de simulação numérica são importantes aliadas, pois permitem estimar a vida em fadiga dos mesmos ainda na fase de concepção, reduzindo custos em garantias, protótipos e tempo despendido no desenvolvimento de um novo produto. A vida em fadiga dos componentes e estruturas metálicas pode ser definida através de duas principais abordagens: domínio do tempo ou domínio da frequência, também chamado de métodos espectrais. Esta abordagem apresenta tanto excitações quanto respostas em termos de Densidade Espectral de Potência - PSD, enquanto a abordagem no domínio do tempo apresenta excitações e respostas em termos de históricos temporais. O uso de métodos espectrais possui como vantagens a redução do esforço computacional, melhor entendimento do comportamento dinâmico da estrutura, além de permitir a análise de trechos representativos das pistas por onde o implemento trafega. O presente trabalho apresenta uma metodologia para estimativa da vida em fadiga de componentes de implementos rodoviários, além de um estudo de caso, utilizando métodos espectrais. A solução do problema faz uso de acelerações aquisitadas em pistas de asfalto e estrada de chão e estes valores são utilizados como dados de entrada na estimativa da vida em fadiga do componente em estudo. Efeitos das tensões médias e critérios de multiaxialidade também foram abordados. / About 60% of the total cargo transported in the country makes use of highways, however only 13.5% of the country's roads are paved, and 48% of them have some type of disability. Inserted in this context there are approximately 1300 manufacturers of road implements, vehicles designed specifically to the transport of cargo. The scenario highlights the competition in this segment. In order to remain competitive, that companies must offer products with higher quality, durability, safety and lower cost. One of development the stages that consumes more resources from these companies is the durability evaluation of their products and, in this aim, numerical simulation tools are important allies, as they allow to estimate the fatigue life of them, still in the design phase, reducing costs in guarantees, prototypes and the time spent in the development of a new product. The fatigue life of components and metallic structures can be defined by two main approaches: the time domain and the frequency domain or spectral method. This spectral approach has both excitations and responses in terms of the Power Spectral Density - PSD, while the time domain approach involves the excitations and responses in terms of some history of time. The use of spectral methods have the advantage of reducing the computational effort, a better understanding of the dynamic behavior of the structure, and allows the analysis of more representative sections of tracks where the implement travels. This work uses one specific methodology for fatigue life assessment of components of road implements, besides a study of some particular case, using spectral methods. The solution of the problem makes use of experimental accelerations measured in paved and unpaved roads, where they are used as input data in the fatigue life assessment of the component in study. Mean stress effects and multiaxial stresses criteria were also considered.

The purpose of this study was to demonstrate a new approach in the analysis of teaching procedures, and show the importance of certain variates on the academic performance of college students. Objectives: The objectives of this study were threefold: To determine whether an ABA approach (definition on page 19) can be used effectively to identify relevant variables influencing college student's academic performance. To determine the influence of grading and exam frequency on achievement in college. To compare the effectiveness of a lectureless go-at-your-own-pace teaching procedure and lecture procedures on student performance as measured on a final exam and a six month retention test. Method Experiment One. Using an ABA reversal procedure in a Latin square design 253 students were rotated through testing conditions to determine the effects of grading and exam frequency on college students academic performance. The four testing conditions were: (a) weekly exams given which counted towards the student's grade, (b) weekly exams given which did not count toward their grade, (c) monthly exams which counted, and (d) monthly exams which did not count. An analysis of the results with respect to the students' grade point average was also carried out. Experiment Two. Three classes of introductory psychology were used in an interclass comparison. Each class was exposed to a different teaching procedure. Daily lectures with a monthly exam were used on the first class. Daily lectures with weekly exams were administered to the second class. The third class attended no lectures, took oral and written exams on each chapter when they felt read y for them, had to master one chapter before progressing to the next, and received immediate feedback on their test results. All three classes were also given a retention test six months later. Students performance on both the final exam and retention test were compared. Results Experiment One. Grading was found to significantly influence students academic performance (p .05). Though exam frequency had a consistent and systematic effect on performance, its effect was not found statistically significant. It was also noted that both variates influenced students of all grade point average ranges to the same degree rather than differentially helping only certain grade levels. Experiment Two. It was found that the students in the go-at-your-own-pace group outscored both lecture classes on the final exam and six month retention test. Conclusions The following conclusions are drawn from the results of research conducted for this report. The lack of differential effects in past comparative studies is due to the fact that the students' academic behavior was not differentially influenced. Intraclass analytic procedures can be employed which are more sensitive than the interclass comparisons employed in the past. Instructors can use grading to strongly influence college students of all grade point ranges to perform better. Two things future research in college teaching should include are: (a) more sensitive experimental procedures, and (b) a change in the variates analyzed. A stronger look should be taken at what behavioral contingencies the course includes rather than only what the teacher does in class. It is suggested that higher education should direct itself to more contingent systems of instruction rather than shifting to more self-controlled learning situations.

Master of Science / Department of Mechanical and Nuclear Engineering / Kevin B. Lease / Xiao J. Xin / The study of buckling behavior of tubular and cellular structures has been an intriguing area of research in the field of solid mechanics. Unlike the global Euler buckling of slender structures under compressive loads, tubular and cellular structures deform with their walls buckling as individual supported plates. The aspect ratio and the dimensional characteristics of the tube define the buckling behavior of any tube structure. In this thesis, a thorough study on the buckling of polygon tubular structures with different cross sections is discussed. In the first study, the theoretical buckling formulation of a square tube using the energy method is reviewed from existing solutions in literature. The elastic critical load of a square tube derived from the theoretical solution is then compared with results of finite element elastic buckling simulations. The formation of lobes along the height of the walls at different aspect ratios of the tube is investigated and compared to theory. Also, the buckling behavior of multi-wall structures is studied and the relationship between these structures and a rectangular simply supported plate is established. A brief study on the buckling behavior of rhombic tubes is also performed. The results of the simulation match closely with the theoretical predictions. The study is then extended to quadrilateral tubes with cross-sections in the shape of square, rectangle, rhombus and parallelogram. The theory of buckling of these tubes is explicitly defined using classical plate mechanics based on the previous works presented in literature. Also, the possibility of global Euler buckling in the tubular structures after a certain critical height is discussed. The prediction from the theory is validated using extensive finite element elastic buckling simulations and experimental tests on square and rhombic tube specimens. The results of the simulations and experiments are observed to be consistent with the theory. Using the formulation of plate buckling under different boundary conditions, the buckling behavior of triangular tubes is also determined. A theoretical formulation for calculating the critical load of triangular tubes is derived. The theoretical critical loads for a range of aspect ratios are compared with corresponding finite element simulation results. The comparisons reveal high degree of similarity of the theoretical predictions with the simulations.

<p>Дефинисани су експeримeнтaлни поступци за oдрeђивaњe губитака и стeпeнa искoришћeњa пoстрojeњa у зaвиснoсти oд рeлaтивнoг oптeрeћeњa кaбинe (кoшa) у експлоатационим условима, као и за oдрeђивaњe мeхaничких кaрaктeристикa чeличних ужaди.<br />Дата је мoгућнoст примeнe мeтoдa нумeричкe aнaлизe зa рeшaвaњe систeмa ПДЈ хипeрбoличнoг типa са константним параметрима и граничним условима што одговара случајевима осциловања кабине (коша) након заустављања (кочења) погонског мотора.<br />Развијени су aдeквaтни прoрaчунски мoдeли који омогућују комплексну динaмичку aнaлизу лифтoвa и извoзних пoстрojeњa у функцији прoмeнљиве крутoсти и граничних услова. Дефинисан је утицај променљиве крутости нa стaбилнoст крeтaњa, кроз прoмeну слободне дужине ужади.</p> / <p>Definisani su eksperimentalni postupci za određivanje gubitaka i stepena iskorišćenja postrojenja u zavisnosti od relativnog opterećenja kabine (koša) u eksploatacionim uslovima, kao i za određivanje mehaničkih karakteristika čeličnih užadi.<br />Data je mogućnost primene metoda numeričke analize za rešavanje sistema PDJ hiperboličnog tipa sa konstantnim parametrima i graničnim uslovima što odgovara slučajevima oscilovanja kabine (koša) nakon zaustavljanja (kočenja) pogonskog motora.<br />Razvijeni su adekvatni proračunski modeli koji omogućuju kompleksnu dinamičku analizu liftova i izvoznih postrojenja u funkciji promenljive krutosti i graničnih uslova. Definisan je uticaj promenljive krutosti na stabilnost kretanja, kroz promenu slobodne dužine užadi.</p> / <p>We have defined the experimental procedures for defining the dissipation and the utility factor of vertical transport machines depending on the relative loading of the cabin (cage) in exploiting conditions, as well as for the setting the mechanical charactristics of the steel ropes.<br />There is given the option of applying the numerical analyses methods for solving the PDE systems of the hyperbolic type with constant parameters and boundary conditions, which is suitable for the cases when there are oscillations of the cabin (cage) after stopping (braking) the driving motor.<br />The adequate calculation models have been developed and they enable a complex dynamic analyses of elevators and mine elevators in the function of variable stiffness and boundary conditions. We also defined the influence of the variable stiffness on the stability of movement, through a change in the ropes&rsquo; free length.</p>

Made available in DSpace on 2016-04-28T20:39:43Z (GMT). No. of bitstreams: 1 Rafael Domingues Adaime.pdf: 2962262 bytes, checksum: f1d0a77fd261ce9788d1ea724b3760a7 (MD5) Previous issue date: 2008-03-27 / This dissertation is a study of experimental procedures in psychotherapy, in which I intend to give visibil ity through some cases and theoretical elements, to the way I have worked at the clinic through experimentation, by the influence of the work of Gilles Deleuze and Felix Guattari, the schizoanalysis / Esta dissertação é um estudo sobre procedimentos experimentais em psicoterapia, em que procuro dar visibil idade, através de alguns casos e elementos teóricos, para o modo como tenho trabalhado na clínica pela via da experimentação, por influência da obra de Gilles Deleuze e Félix Guattari, a esquizoanálise