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Modelagem paramétrica de pórticos rolantes: estabilidade estrutural e otimização. / Gantry cranes parametric modeling: structural stability and optimization.Gustavo Sobue 29 July 2005 (has links)
O objetivo deste trabalho é desenvolver uma ferramenta de automatização de cálculo para projeto estrutural de pórticos rolantes. Com o apoio da geração automática de um modelo de elementos finitos e um memorial de cálculo, o projeto estrutural desses equipamentos pode ser rapidamente verificado quanto ao limite de escoamento do material e resistência à flambagem. Optou-se pela utilização do método dos elementos finitos para o cálculo estrutural, pois se trata de uma ferramenta de cálculo moderna, que permite avaliar soluções para as quais não há ferramentas analíticas disponíveis. Porém, o tempo para geração de modelos de cálculo pode ser longo em relação ao cronograma do projeto, principalmente se houver a necessidade de se alterar a geometria inicial ou se existirem várias condições de carregamento a serem analisadas. A utilização de um pré-processador permite que várias alternativas sejam analisadas para escolha da que melhor atenda aos requisitos de projeto e de custo. Assim como ocorre com outras estruturas de engenharia, não existe uma equação de dimensionamento, mas sim de verificação; as estruturas ótimas são procuradas por tentativa e erro com base na experiência do projetista. Para facilitar a busca de uma estrutura ótima, implementou-se também uma rotina para otimizar as estruturas metálicas do pórtico. Adotou-se como função objetivo nesta implementação a minimização da massa, o que no caso dos pórticos implica em redução da área da seção transversal das vigas. Como restrições a esta redução adotaram-se o limite de escoamento do material e limite de estabilidade da estrutura (flambagem). Foram utilizados os aplicativos Excel (Microsoft), Ansys (Ansys Inc.) e Mathcad (Mathsoft) de maneira integrada a fim de se obter uma interface amigável, uma análise estrutural confiável e a elaboração automática de um memorial de cálculo. / The objective of this work is to develop a tool to generate an automatic structural design of gantry cranes. With an automatic generation of finite element models and also a design report, this routine allows a fast verification against yield of material and structural instability. The use of the finite element method was chosen for the structural design because it is a modern analysis tool that permits the evaluation of geometric configurations for which there are no analytical formulations available. However, the time necessary to build these models may be high, especially if there are changes in the initial geometry and many load cases. The use of a pre-processor allows the evaluation of a series of geometric alternatives, within which would be chosen the one with the lowest cost that attends the clients specifications. Like many other engineering problems, there are no direct equations to find an adequate structure; there are only verification procedures available; the optimum structures are searched by trial and error, based on the designers experience. To accelerate this search process, an optimization routine was developed. Mass reduction was adopted as the objective function, which leads to reduction of the cross section area of the beams. Yield strength and buckling were adopted as restrictions to this optimization. Excel (Microsoft), Ansys (Ansys Inc) and Mathcad (Mathsoft) software were integrated to provide an user-friendly interface, reliable structural analysis and an automatic report generation.
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The weight lifting belt’s impact on power output, velocity and range of motion in a squatEngberg, Amanda January 2017 (has links)
Abstract Background: Using a weight lifting belt when performing a variety of resistance exercises is becoming more and more common. The purpose of using a weight lifting belt is its supposed ability to reduce compressive forces on the lumbar spine and enhancement of athletic performance. Although the weight lifting belt has been proven to increase the intra abdominal pressure that helps reduces the shear forces during a squat, little is known about the weight lifting belts effect on the performance. Studies have suggested that wearing a weight lifting belt during a squat can increase the vertical velocity and range of motion. Few studies have focused on the power output, but improvements have been seen while wearing a weight lifting belt when performing a deadlift. Variables such as power, velocity and range of motion are of importance for an athlete when making individual training plans as well as measuring the progress. Therefore more research is needed to identify the actual influence of the weight lifting belt on the performance. Aim: The purpose of this study was to examine if weight lifting belts have an impact on an athletes ability to develop power, velocity or improve range of motion in a squat. Methods: Fifteen healthy men and women familiar with the squat exercise participated in the study. During the study they performed six repetitions of the squat divided into two sets, one set without a weight lifting belt and one with a weight lifting belt. Power and velocity were measured during every squat with a linear encoder and videotapes were made to later calculate the angles in the hip- and knee joints at the lowest position of the exercise. Results: No significant differences were found in power (p = 0.25) or concentric and eccentric velocity (p = 0.61, p = 0.16) with or without a weight lifting belt. Range of motion in the knee joint was greater when not wearing a weight lifting belt (p = 0.03), but no differences in the hip angles were found (p = 0.70). Conclusion: The result from the current study shows that when performing a squat the weight lifting belt has little to no effect on power, velocity or range of motion. Although a noticeable change in range of motion of the knee joint were observed, further studies on larger populations are needed to determine if it is of clinical value.
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Resposta da pressão arterial durante exercício resistido em hipertensos:influência de anlodipina. / Blood pressure responses to dynamic resistance exercise: influence of amlodipineDinoelia Rosa de Souza 09 November 2012 (has links)
O exercício resistido dinâmico é recomendado para hipertensos, mas a pressão arterial (PA) se eleva muito durante sua execução. Este estudo investigou o efeito do antagonista do canal de cálcio diidropiridínico, anlodipina, sobre a resposta da PA ao exercício resistido de diferentes intensidades. Onze hipertensos essenciais foram estudados após 4 semanas de uso de placebo e anlodipina, num desenho aleatório e duplo cego. Os voluntários realizaram o exercício de extensão de joelhos até a exaustão, seguindo os seguintes protocolos: a) 1 série em 100% de 1RM, b) 3 séries em 80% de 1RM; e c) 3 séries em 40% de 1RM. Antes e durante os exercícios, a PA foi medida diretamente na artéria radial. A anlodipina reduziu os valores absolutos da PA sistólica (225±6 vs 207±6 mmHg em 100%, 289±8 vs 273±10 mmHg em 80% e 289±10 vs 271±11 mmHg em 40%) e da PA diastólica (141± 3 vs 130±6 mmHg em 100%, 178±5 vs 169±6 mmHg em 80% e 176±8 vs 154±6 mmHg em 40%) em todas as intensidades. Ela também minimizou o aumento da PA diastólica que ocorreu na 2ª e 3ª séries do exercício realizado em 40% de 1 RM. Em conclusão, anlodipina é capaz de diminuir os valores máximos da PA atingidos durante a realização de exercícios resistidos de diferentes intensidades e minimizar o aumento progressivo da PA diastólica em exercícios mais prolongados.Estes efeitos podem reduzir o risco cardiovascular durante a execução de esforços resistidos em hipertensos / Dynamic resistance exercise is recommended for hypertensives. However, during its execution blood pressure (BP) presents a huge increase. This study investigated the effects of dyhidropyridine calcium channel antagonist, amlodipine, on BP responses during resistance exercises executed at different intensities. Eleven essential hypertensives were studied after 4 weeks of placebo and amlodipine administered at a random double blinded order. Volunteers were evaluated during the execution of the knee extension exercise performed with three different protocols: a) 1 set at 100% of 1RM (repetition maximum), b) 3 sets at 80% of 1RM, and c) 3 sets at 40% of 1RM. Before and during exercise, BP was directly measured at the radial artery. Amlodipine reduced the absolute values of systolic BP (225±6 vs 207±6 mmHg at 100%, 289±8 vs 273±10 mmHg at 80% e 289±10 vs 271±11 mmHg at 40%) and diastolic BP (141± 3 vs 130±6 mmHg at 100%, 178±5 vs 169±6 mmHg at 80% e 176±8 vs 154±6 mmHg at 40%) during all the exercise intensities. In addition, it mitigated diastolic BP increase that happened at the second and third sets of the exercise at 40% of 1 RM. In conclusion, amlodipine was able to decrease BP maximal values achieved during resistance exercise at different intensities, and minimizes diastolic BP increase in prolonged resistance exercises. These effects may confer some cardiovascular protection for hypertensives during the execution of resistance efforts
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Mechanické zajištění hydraulických zdvihacích systémů pro jevištní techniku / Mechanical securing of hydraulic lifting systems for stage technologyDrha, Vojtěch January 2018 (has links)
The aim of this thesis is to design a mechanical position securing of hydraulic elevating systems for stage technology. The first part includes an overview of present state of elevating systems and their securing solutions. The second part determines technical parameters and design of a chosen solution together with control and design calculations. Final part analyses suggested solution in terms of security.
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Pomocná jeřábová kočka 10000 kg / Auxiliary crane trolley 10000 kgMilichovský, Karel January 2019 (has links)
This master thesis deals with design of auxiliary crab trolley with load capacity 10t. Crab trolley moves along outdoor track of scrab yard. The target of this thesis is calculation and own design of travelling and lifting gear, strength calculation of frame and drawing documentation of a crane trolley assembly.
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Návrh výrobní technologie pro zdvihací zařízení chladiče traktoru / Production technology of a lifting equipment for tractor coolerRaiskup, Martin January 2019 (has links)
The thesis focuses on production technology of the lifting equipment for a tractor cooler. This device is used in order to ease the installation of a cooler during the manufacturing of a tractor. In the first chapter, various types of the lifting equipment are described. In the following chapters manufacturing methods, machines and tools for the production of the specific component are described. Furthermore, materials and manufacturing processes for the complementation of the specific component are proposed. In the conclusion, the methods for the manufacturing are suggested, the timescale is calculated and the technical-economical evaluation is performed.
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Zakázkový projekt na zdvihací zařízení / Custom design for lifting equipmentMatějíčková, Eva January 2020 (has links)
The aim of this thesis is to design and manufacture a lifting device to the Volkswagen Crafter long vehicle. In the first part, I present a simple descriptive overview of different lifting devices based on their principle and use. Next, commercially available alternative solutions to the given problem are shown and discussed. The main goals of the practical part are the design of the lifting device that fits to a carriage van according to given specifications and the description of the technological processes for the manufacturing of individual components of the device. The design includes selection of proper machines, measuring devices and working tools, which was carried out based on the available equipment. Finally, manufacturing, testing and evaluation are described and discussed together with the possibilities for future improvement.
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Drapák pro manipulaci s dřevem / Grab sampler for handling with woodKučera, Jakub January 2008 (has links)
The assignment of this thesis is a design of the wood manipulation grab to be used with small hydraulic cranes. The aim is to design a grab with lifting capacity of 2000 kg. The results of thesis can be used to diversify production of the company Agama a.s. Primarily, the grab should be lightweight, easy to manufacture and affordable.
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Zvedací zařízení pro formulový vůz / Lifting Unit for Formula CarHavel, Jan January 2010 (has links)
In this thesis, the author deals with structural design of lifting unit for the formula car. First, he searches in the currently used solutions, followed by selection of appropriate accessories, a preliminary analytical calculation and stress analysis model. In the last part, there is made economic and weight balance.
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Skidová dopravníková technika / Skid conveyor technologyFajkus, Pavel January 2014 (has links)
This diploma thesis deals with planning conveyor technology in welding factory in Kvasiny and concept proposal of stacking equipment for skids. The report contains summary of conveyor technology in Škoda Auto a.s., description of the planning process about connection line from new hall to the existing hall, proposal of stacking equipment constructional variants, mechanism load stress analysis, inner effects results and verification by final elements method (MKP) components of the choice.
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