Flexural mechanism design is one of the latest field for mechanism researches in these recent years. In this paper, it will address one method of normalized dimensional parameters. According to the traditionally change of the appearance of flexural hinge, the different parameters will be designed through to the differences of several combination. On the other hand, we use the Finite Element Method to analyze the kinematics behavior of different hinges. Finally, we come up with a series of complete data that provide designers a reference for designing.

Linear-motion compliant mechanisms have generally been developed for small displacement applications. The objective of the thesis is to provide a basis for improved large-displacement linear-motion compliant mechanisms (LLCMs). One of the challenges in developing large-displacement compliant mechanisms is the apparent performance tradeoff between displacement and off-axis stiffness. In order to facilitate the evaluation, comparison, and optimization of the performance of LLCMs, this work formulates and presents a set of metrics that evaluates displacement and off-axis stiffness. The metrics are non-dimensionalized and consist of the relevant characteristics that describe mechanism displacement, off-axis stiffness, actuation force, and size. Displacement is normalized by the footprint of the device. Transverse stiffness is normalized by a new performance characteristic called virtual axial stiffness. Torsional stiffness is normalized by a performance characteristic called the characteristic torque. Because large-displacement compliant mechanisms are often characterized by non-constant axial and off-axis stiffnesses, these normalized stiffness metrics are formulated to account for the variation of both axial and off-axis stiffness over the range of displacement. In pursuit of mechanisms with higher performance, this work also investigates the development of a new compliant mechanism element. It presents a pseudo-rigid-body model (PRBM) for rolling-contact compliant beams (RCC beams), a compliant element used in the RCC suspension. The loading conditions and boundary conditions for RCC beams can be simplified to an equivalent cantilever beam that has the same force-deflection characteristics as the RCC beam. Building on the PRBM for cantilever beams, this paper defines a model for the force-deflection relationship for RCC beams. Included in the definition of the RCC PRBM are the pseudo-rigid-body model parameters that determine the shape of the beam, the length of the corresponding pseudo-rigid-body links and the stiffness of the equivalent torsional spring. The behavior of the RCC beam is parameterized in terms of a single parameter defined as clearance, or the distance between the contact surfaces. The RCC beams exhibit a unique force-displacement curve where the force is inversely proportional to the clearance squared. The RCC suspension is modeled using the newly defined PRBM. The suspension exhibits unique performance, generating no resistance to axial motion while providing significant off-axis stiffness. The mechanism has a large range of travel and operates with frictionless motion due to the rolling-contact beams. In addition to functioning as a stand-alone linear-motion mechanism, the RCC suspension can be configured with other linear mechanisms in superposition to improve the off-axis stiffness of other mechanisms without affecting their axial resistance.

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No. of bitstreams: 1 DissEJA.pdf: 12810392 bytes, checksum: 80fef2ab76f23b539c00768be1473dde (MD5) Previous issue date: 2017-04-27 / Não recebi financiamento / Being a global phenomenon, the motorization process has advanced in the last decades and is characterized mainly by the increase of motor vehicles used in the individual transport. The evidence suggests the association of the process with the deficiencies of public transport, the model of urban land occupation and the economic policies to encourage the automobile industry in recent decades. In view of the aggravation of the national scenario, the new guidelines of the National Urban Mobility Policy were instituted in 2012 with the purpose of encouraging the use of collective transportation and non-motorized modes. In spite of representing an innovation, with admittedly positive propositions, several questions are raised, especially regarding the financing of infrastructure and the sharing of the costs of public transport and other initiatives aimed at urban mobility. The new legislation did not give due attention to motorcycles, as it saw them under the same conditions as cars and other motor vehicles, despite their recognized vulnerability. This is the reason why small safety initiatives in the use of this type of vehicle are important. It was verified that some parking spaces for motorcycles available on the campus São Carlos of the UFSCar have reduced dimensions or some difficulty for their access, besides the disproportionality in front of the offer of vacancies for the automobiles. The hypothesis was then formulated about the outdating of the parameters used in the distribution of the vacancies, dimensions and in the maximum slope of the floor, particularly in parking lots positioned outside the streets. The bibliographic review was applied to collect propositions regarding these parameters. A questionnaire was also sent to the municipal transit authorities, which allowed verification the criteria for the deployment of new parking lots. The case study was used to analyze the adopted parameters and was inferred by the veracity of the initial hypothesis. It was also verified that in the majority of the studied cases the size of the vacancies do not follow the recommendation of the regulator of traffic. It was found that the distribution of parking spaces between motorcycles and automobiles does not correspond to the proportion observed in the municipal, state and regional vehicle fleet. It was concluded that the specificities of the motorcycles were not considered in relation to the inclination of the floor of the parking lots. Based on the information obtained during the research, the proposals for adequacy for UFSCar parking lots were made. / Sendo um fenômeno global, o processo de motorização tem avançado nas últimas décadas e se caracteriza principalmente pelo aumento de veículos motorizados empregados no transporte individual. As evidências sugerem a associação do processo às deficiências do transporte público, ao modelo de ocupação do solo urbano e as políticas econômicas de incentivo à indústria automobilística das últimas décadas. Diante do agravamento do cenário nacional, instituiu-se no ano de 2012 as novas diretrizes da Política Nacional de Mobilidade Urbana com o propósito de incentivar o uso do transporte coletivo e dos modos não motorizados. A despeito de representar uma inovação, com proposições reconhecidamente positivas, diversos questionamentos são levantados, especialmente no que diz respeito ao financiamento da infraestrutura e à repartição dos custos do transporte público e de outras iniciativas voltadas à mobilidade urbana. A nova legislação não dispensou a devida atenção às motocicletas, pois as contemplou nas mesmas condições dos automóveis e demais veículos motorizados, apesar da sua reconhecida vulnerabilidade. Por esse motivo tornam-se importantes as pequenas iniciativas voltadas à segurança na utilização desse tipo de veículo. Verificou-se que algumas vagas de estacionamento de motocicletas disponibilizadas no campus São Carlos da UFSCar apresentam dimensões reduzidas ou alguma dificuldade para o seu acesso, além da desproporcionalidade frente à oferta de vagas para os automóveis. Formulou-se, então, a hipótese sobre a desatualização dos parâmetros empregados na distribuição das vagas, nas dimensões e na inclinação máxima do piso, particularmente em estacionamentos posicionados fora das ruas, do tipo “bolsão”. Aplicou-se a revisão bibliográfica para colher proposições a respeito desses parâmetros. Também foi enviado um questionário às autoridades municipais de trânsito, que permitiu verificar os critérios de implantação de novas vagas. Utilizou-se o estudo de casos para analisar os parâmetros adotados e inferiu-se pela veracidade da hipótese inicial. Verificou-se, ainda, que na maioria dos casos estudados as dimensões das vagas não seguem a recomendação do órgão regulador de trânsito. Constatou-se que a distribuição das vagas de estacionamento entre motocicletas e automóveis não corresponde à proporção observada na frota de veículos municipal, estadual e regional. Concluiu-se que as especificidades das motocicletas não foram consideradas em relação à inclinação do piso dos estacionamentos. Com base nas informações obtidas durante a pesquisa foram feitas as proposições de adequação para os estacionamentos da UFSCar.