Análise do comportamento em fadiga de rodas ferroviárias fabricadas pelos processos de forjamento e fundição

Since the beginning of the railway industry until today, rail wheels are important components to the good working of a railway. For being a critical security item, design and maintenance are done with extremely care to avoid failures. Despite de fact of railway components be projected to support a big number of cyclic solicitation during its life, some accidents still occur. These accidents, despite the low frequency, always have great consequences, drawing in great financial, material, and people losses. Nowadays, railway component failure is relatively low, because it’s been projected to work below the materials Fatigue Resistance Limit, however, with the growing demand of faster trains and higher load for each axle, the occurrence probability is even bigger. This work includes a comparative study of two fabrication processes (casting and forging) applied in the production of rail wheels where it was measured the mechanical properties of traction and fatigue. The study also verified through microstructural analysis, hardness, traction and fatigue tests, statistical analysis of fatigue test results and fractographic analysis that forging process lead to better correlations between fatigue life and mechanical properties, providing more security in railroads, less wagon retention caused by corrective maintenance and smaller operational cost with its use

Controle de velocidade e tração de rodas independentes para veículos elétricos

This work presents a proposal to replace thetraditional system of traction electric car that usesone electric motor and a mechanical differential, by two electric motors of lower power, controlled byelectronic control low cost. The proposed control isopen loop and uses the technique of Pulse WidthModulation (PWM), discrete and synchronizedaiming to reduce the generation of harmonics. The implementation of two smaller motor one on each wheel-drive distributes the weight of the vehicle, improving the heat exchange of the windings,beyond enable the power components supporting a current of 50% predicted for only one motor . The solution adopted for being open-loop, has a similar behavior to the mechanical differential, where theeffort imposed by the trajectory makes the velocity distribution between the wheels be appropriate tovehicle trajectory

Análise de fadiga em rodas automotivas utilizando método dos elementos finitos

The increasing search for better performance at the automotive industry, especially on the matter of fuel consumption, caused a progressive evolution of industrial technology. For the wheel this study is based on the try of reducing mass and decreasing the moment of inertia, characteristics that directly reflect on the performance parameter, as consumption and acceleration, so that it also is effective on the growth of the profit margin, since it reduces the costs of the locomotion. In this paper will be applied the Finite Element Analysis to explain the wheel behavior and identify ways to improve the performance. To the analyze it will be simulated a test condition established by ABNT NBR 6751:2009 foreseeing a possible collapse through general yielding and fatigue. The load here presented results from the equation presented on the norms and in the datas provided by the manufacturer

Relação entre carga parasitária de cães naturalmente acometidos por leishmaniose visceral e infectividade para Lutzomyia longipalpis: Lilian Aparecida Colebrusco Rodas. -

Pós-graduação em Ciência Animal - FMVA

Disposição construtiva aplicada em cadeira antropométrica

Disposição construtiva aplicada em cadeira antropométrica. Patente de modelo de utilidade para uma cadeira antropométrica constituída de uma estrutura (1) que sustenta uma pluralidade de instrumentos de medição, sendo que a parte posterior da cadeira é provida de dois instrumentos de medição compostos por duas hastes, sendo uma delas para medida da altura tronco-encefálica (2) e a outra para a medida do assento até a região renal (4), de modo que cada uma dessas hastes possui uma escala numérica, sendo ora interna (3), ora externa (5). O assento (6) da cadeira (1) é composto por um anteparo com uma canaleta interna e dois cursores laterais deslizantes para a direita e para a esquerda, que possuem escala numérica.; O assento é provido de referências métricas sendo uma no sentido da largura do assento (8) e outra no sentido da profundidade do assento (9), sendo a escala (8) dividida em duas escalas, onde o ponto zero é exatamente o meio do assento. O assento (6) também possui acoplada uma haste frontal, com deslizamento no sentido antero-posterior (10), a qual contém uma escala interna embutida na peça, de modo que a soma entre a medida da profundidade do assento com a medida obtida pela haste deslizante horizontal (10) totalizam a medida sacro-poplítea. Para a tomada da medida da altura poplítea, há uma outra haste (11), integrada à superfície anterior da cadeira, cujo deslizamento é vertical, sendo que essa haste (11) possui uma escala numérica interna uma externa (12).; A base da cadeira (13) possui um dispositivo de acionamento lateral com o pé (16), que é conectado ao assento (6) por meio de um macaco hidráulico, permitindo a elevação do assento, sendo que a outra alavanca (17), ao ser girada, realiza a descida do assento (6).

Sexualidade e adolescência: rodas de conversa e vivências em uma escola de ensino fundamental

Pós-graduação em Educação Sexual - FCLAR

Aplicação da Simulação de Monte Carlo no estudo de testes de fadiga em rodas agrícolas

Due to the increasing demand from clients and the search for better performances in the heavy vehicles industry, a progressive evolution in technology in a general way was needed. This paper uses a scientific method to validate, prior to its manufacture, the project of an agricultural wheel for sugar cane harvesters. Monte Carlo Simulation is used in conjunction with Finite Elements Method, in order to simulate the wheel's behavior in a cornering test, identify possible failure regions and get an estimate for its life under fatigue. To this end, test conditions according to EUWA Standards were simulated and obeyed, relevant to fatigue. Simulation results were interesting, according to industry experts involved in the project and manufacture of the product in question, and have provided important elements for the decision making regarding improvements that could be made on the product project before its execution

Aplicação da Simulação de Monte Carlo no estudo de testes de fadiga em rodas agrícolas

Due to the increasing demand from clients and the search for better performances in the heavy vehicles industry, a progressive evolution in technology in a general way was needed. This paper uses a scientific method to validate, prior to its manufacture, the project of an agricultural wheel for sugar cane harvesters. Monte Carlo Simulation is used in conjunction with Finite Elements Method, in order to simulate the wheel's behavior in a cornering test, identify possible failure regions and get an estimate for its life under fatigue. To this end, test conditions according to EUWA Standards were simulated and obeyed, relevant to fatigue. Simulation results were interesting, according to industry experts involved in the project and manufacture of the product in question, and have provided important elements for the decision making regarding improvements that could be made on the product project before its execution

Teócrito (Idilios 13 y 22), Apolonio de Rodas (II 282-283) y Propercio I 20 : Una contaminación

Este artículo analiza la contaminación que de los idilios 13 y 22 de Teócrito y de los versos II 282-283 del poema de Apolonio de Rodas realiza Propercio en su elegía 1, 20.

Teócrito (Idilios 13 y 22), Apolonio de Rodas (II 282-283) y Propercio I 20 : Una contaminación

Este artículo analiza la contaminación que de los idilios 13 y 22 de Teócrito y de los versos II 282-283 del poema de Apolonio de Rodas realiza Propercio en su elegía 1, 20.

Teócrito (Idilios 13 y 22), Apolonio de Rodas (II 282-283) y Propercio I 20 : Una contaminación

Este artículo analiza la contaminación que de los idilios 13 y 22 de Teócrito y de los versos II 282-283 del poema de Apolonio de Rodas realiza Propercio en su elegía 1, 20.