Predictive maintenance of a worm reducer with an unbalanced load

Among all predictive maintenance techniques the oil analysis and vibration analysis are the most important for monitoring some mechanical systems. The integration of these techniques has potential to improve industrial maintenance practices and provide a better economic gain for industries. To study the integration of these two techniques, a test rig was set up to obtain an extreme working condition for the worm reducer used in this paper. The test rig was composed by a motor connected to a reducer through a flexible coupling and with an unbalanced load. The analysis of the results carried out by using a sample of the oil recommended by the manufacturer in extreme conditions, and using liquid contaminant is presented. From the results it was observed that if there is an abnormal instantaneous load in a system, the subsequent vibration analysis may not perceive what occurred if there was no permanent damage, which is not the case with the lubricant analysis.

A single bout of exercise with a flexible pole induces significant cardiac autonomic responses in healthy men

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Model updating of the non-linear vibrating structures through Volterra series and proper orthogonal decomposition

Classical procedures for model updating in non-linear mechanical systems based on vibration data can fail because the common linear metrics are not sensitive for non-linear behavior caused by gaps, backlash, bolts, joints, materials, etc. Several strategies were proposed in the literature in order to allow a correct representative model of non-linear structures. The present paper evaluates the performance of two approaches based on different objective functions. The first one is a time domain methodology based on the proper orthogonal decomposition constructed from the output time histories. The second approach uses objective functions with multiples convolutions described by the first and second order discrete-time Volterra kernels. In order to discuss the results, a benchmark of a clamped-clamped beam with an pre-applied static load is simulated and updated using proper orthogonal decomposition and Volterra Series. The comparisons and discussions of the results show the practical applicability and drawbacks of both approaches.

Biotecnologias aplicadas à reprodução de éguas velhas

The acceptance of biotechnology for the most equine breeders association had a significant effect in the horse industry, gaining popularity around the world, because the increasing on the genetic gain, allowing the use of sub fertile mares and stallions with high genetics value on reproduction. The embryos in vitro production of human and cattle has been used with success, however in vitro embryo production is not efficient in the horse, as oocyte transfer (OT) and intracytoplasmatic sperm injection (ICSI). The oocyte transfer has been used especially in subfertile old mares presenting reproductive pathologies as: endometrite, cervical and uterine adhesions, blocked oviduct, perineal laceration and ovulation failures. During oocyte recovery process, the oocytes must be collected from immature follicles that need be matured in vitro or in vivo matured oocytes from pre-ovulatory follicles through the transvaginal aspiration guided by ultrasound. The recovered oocyte is transferred to a previously inseminated recipient mare, through the flank laparotomy. The intracytoplasmatic sperm injection (ICSI) is a procedure of in vitro fertilization that needs only one sperm that is aspirated and injected inside the oocyte. The oocytes used, can be from mature and immature follicles. Fresh, cooled and frozen semen can be used, because the procedure not requires a functional sperm. The use of Piezo drill resulted in a breakthrough the pellucid zone, allowing the vibration per minute provided in the sperm injection pipette, a major result of cleaved oocytes, due to a better sperm injection in the oocyte. The embryo transfer can be straight inside the oviduct, as also transcervical transferred after embryo culture produced in vitro. In conclusion both procedures (OT and ICSI) are effective to be used on equine assisted reproduction, getting results even lower than expected, but satisfactory from animal genetically superior

Dimensionamento de suspensões veiculares para isolamento de vibrações excitadas pela via

This work intends to perform the dimensioning of the Guaratinguetá’s Engineering College Baja SAE vehicle suspension system. To do so, concepts of suspension systems, human comfort limits to vibrations and automotive models for suspension vibration analyses are reviewed. On the development of this work descriptions of considerations specific for the vehicle object of this work are made as well as descriptions of the experiment made to determine the stiffness of the tire used. These concepts are applied through a computational routine that allows the dimensioning of springs and shock absorbers of both front and rear axles of a vehicle in a way to respect all the criteria showed during this work and visualize the system’s behavior when excited on different frequencies

Análise da vibração para o controle do funcionamento de um ventilador de um sistema de exaustão

This work has as objective to show the vibrational analysis as a method of predictive maintenance as an auxiliar procedure in the fail detection in equipments, most specifically in the rotative ones, and with that help the maintenance team to have conditions to foresee the right time to do the swap of the components of the systems, what would lead to failures. Knowing the exact moment the resources of people and money can be focused in the critic operations to the plant. This technic has been already studied for more then 30 years and was widely used in this work, not only as an equipment condition verification method, but also, after the equipment replacement, was used to prove that the new fan was operating under the best work conditions and with that maintenance could return to contol the vibration level of the equipment, not being necessary any kind of intervention

Estudo da viabilidade da aplicação de técnicas preditivas na manutenção de reatores batelada

This study aims to analyze the feasibility of using predictive techniques like thermography, vibration analysis, eddy current, liquid penetrant, visual examination and ultrasound in equipment as batch reactors of the type used in a biodiesel production company. This study is based on: analysis of the practices of corrective and preventive maintenance commonly adopted in the company in question, the cost and time spent for such activities and the potential savings and revenue generation that can be after implementation of these techniques on the analysis of maintenance current

Lixamento do Pinus elliotti com carbeto de silício e óxido de aluminio

The Sanding is a complex process involving many variables that affect the quality of the part produced, working mainly in the timber industry in the production of panels (MDF, MDP, HDF, etc...) and furniture. However, these industries use the sanding process empirically, not optimizing it. The aim of this study was to compare the behavior of sandpaper white aluminum oxide (OA-white) and Black silicon carbide (SiC-black), analyzing variables in the process as: strength, power, emission, vibration, wear particle size of sanding, and its consequences on the surface finish of the workpiece. Made the process of plane grinding samples of Pinus elliottii, processed in parallel to the fibers, which were sanded with sandpaper grain OA white and black 3-SiC abrasive conditions (new, moderately eroded and severely eroded) grain sizes in 3 (80, 100, and 120 mesh). 6 replicates was performed for each condition tested. Each trial was captured output variables of the sanding process: strength, power, emission and vibration. With two stages totaling 108 trials. After the sanded samples, it has the same surface quality by raising the surface roughness Ra. Through experiment, it can be concluded that abrasives OA-white tended to have higher strength, power, emissions and less vibration in the sanding process, compared to the SiC-black. However, surface finish exhibited similar to the particle size of 80 to 100 mesh, worn abrasive conditions. However, the particle size of 120 mesh, obtained by the roughness of sandpaper OA-bank was higher compared to SiC-black to all conditions of sandpaper due to its toughness

Espectroscopia de infravermelho e suas aplicações

Infrared spectroscopy (IR spectroscopy) explores the infrared region of the electromagnetic spectrum. Like any other spectroscopic technique, it can be used to identify a compound or the composition of investigate a sample. Spectroscopy (IR) is a very important technique in qualitative chemical analysis, widely used in the chemistry of natural products, organic synthesis and transformations. In this work we study of the theoretical foundations of infrared spectroscopy, the different vibration modes, experimental techniques, and the identification and characterization of solids. Were studied as applications: their use in thermograph and remote sensing satellites

Analise de defeitos em motores através de vibração mecânica: estudo de caso

Revolving machines are among the most used equipment in general industry and therefore expenditures on this equipment class are a significant portion of the total amount spent by the company. If there is an unscheduled stop of some of this equipment, industrial plants can lose huge amounts of money caused by interrupted production and parts delay. Others may increase significantly maintenance costs due to consequences elsewhere not affected before. Even plant and people safety can be in danger if there is an operation interruption without a backup system start. This work is focused on a rotating system case study which is monitored by vibration analysis that shows that is possible to determine when is the most appropriate time for equipment intervention without any reliability loss just by using a simple and cheap system which is not much used because professionals are not aware to its utility. Industrial facilities were evaluated by fail detection and historical analysis in some equipment in order to show feasibility of vibration analysis through a before-during-after process. The plant evaluated is part of a chemical multinational located in Guaratinguetá-SP. At this time, that plant had around 650 critical equipment monthly monitored and no unscheduled shutdown was registered in one year period due to equipment monitoring

Controle de qualidade em estruturas na construção civil

This work is to control the quality of the structures, procedures for addressing the assembly of the formwork, scaffolding and the frame of pillars, beams and slabs. He had also intended to show that the vibration of launch and concrete items are also important, if poorly implemented can undermine the structure. This work also shows that the mapping becomes essential if there is some problem in the concrete, where concrete was launched, could be identified. And finally check the product where the structure will be evaluated for how much their quality

Colheita de energia usando dispositivos baseados em materiais piezoelétrico

Recently, research on energy harvesting has increased substantially. Many researchers have concentrated their efforts to find the best configuration for these systems and to optimize their output power. In the process of energy harvesting, the electric energy is obtained by converting mechanics energy created by an environment vibration source by a transducer, for example, a thin piezoceramic film. That vibration source is, for example, a beam suffering some mechanic force able to generate a vibration in it, an oscillating beam is the best properly used example. Different mechanisms of electromechanical coupling have been developed to harvesting devices, and a particular interest has been given to the use of models that transform the mechanical vibration into electrical current using a piezoelectric element. In this paper we propose a model to energy harvesting from vibrations, from an oscillating beam, including non-linearities in the piezoelectric coupling and a non-ideal excitation in the material. From this model, it was developed a system to obtain some results about the harvested power by the material. It was demonstrated that the power captured was influenced by the effect of the nonlinearities of the piezoelectric coupling, modifying the system dynamic behavior

Avaliação do efeito ambiental nas propriedades mecânicas e viscoelásticas de compósitos híbridos de titânio/fibra de carbono/resina epóxi

Hybrid composites combining metal plates and laminates with continuous fiber reinforced polymer, called fiber-metal (CHMF), have been particularly attractive for aerospace applications, due mainly to their high mechanical strength and stiffness associated with low density. These laminates (CHMF) consist of a sandwich structure consisting of layers of polymer composites and metal plates, stacked alternately. This setting allows you to combine the best mechanical performance of polymer composites reinforced with long fibers, to the high toughness of metals. Environmental effects should always be considered in the design of structural components, because these materials in applications are submitted to the effects of moisture in the atmosphere, the large cyclical variations of temperature around 82 ° C to -56 ° C, and high effort mechanical. The specimens of fibermetal composite were prepared at EMBRAER with titanium plates and laminates of carbon fiber/epoxy resin. This study aims to evaluate the effect of different environmental conditions (water immersion, hygrothermal chamber and thermal shock) of laminate hybrid titanium/carbon fiber/epoxy resin. The effects of conditioning were evaluated by interlaminar shear tests - ILSS, tensile, and vibration free

Determinação da freqüência natural de eixos utilizando o software excel

This work aims to determine the first natural frequency of rotation shaft by using a basic software, Excel, and to compare it to the values obtained in laboratory. When an axle is submitted to a rotation, depending on the rotational frequency used, the axle can enter a state of resonance, in which the amplitude of vibration becomes rather high. The frequencies in which the resonance is observed depends on several parameters of the axle, including the number of concentrated masses associated to the axle. Thus, to obtain a computer program of easy use and access, which can preview the frequency of resonance of an axle in rotation with ‘n’ numbers of concentrated masses it has been studied how the frequency varies with each of these parameters. The computer program and the analyses have been made using the Rayleigh Method, which allowed the transformation of a continuous system to discrete through the theory of finite elements, which has proved that, the bigger the number of divisions of the shaft taken into consideration in the calculus of the natural frequency, the more this value gets close to the real value. The results obtained have been considered satisfactory once these have gotten close to the theoretical results expected

Efeito da plataforma vibratória na recuperação da densidade óssea de ratas ovariectomizadas

As mudanças demográficas decorrentes do envelhecimento populacional têm contribuído substancialmente para o aumento de doenças crônicas não transmissíveis relacionadas à idade, dentre elas está a osteoporose, considerada um dos principais problemas de saúde pública, por sua prevalência crescente e pela associação a fraturas em diversas áreas do corpo, com graves repercussões clínicas e sociais. Com isso vem se buscando cada vez mais alternativas de exercício físico válidas para o combate e prevenção a estas doenças ósseas. Como possível alternativa têm se estudado os efeitos e benefícios dos treinamentos realizados em Plataformas Vibratórias, equipamento que através de baixa amplitude e alta freqüência pode vir a influenciar positivamente nas capacidades físicas. Portanto, devido à escassez de informações acerca dos efeitos do exercício na plataforma vibratória sobre a microarquitetura dos ossos em indivíduos idosos e já acometidos pela osteoporose, o objetivo deste estudo foi, com um modelo animal, descrever através de imagens de Microscopia Eletrônica de Varredura (MEV), a reação do tecido ósseo de ratas idosas ovariectomizadas ao exercício em Plataforma Vibratória. Para execução deste estudo foram utilizadas 20 ratas Wistar (Rattus Norvegicus Albinus Wistar), separadas em 4 grupos: Sedentário Controle (S), Sedentário Ovariectomizado (SO), Treinado Controle (T) e Treinado Ovariectomizado (TO). Como protocolo de treinamento a plataforma vibratória foi regulada com freqüência de 35 Hz e amplitude baixa (1 a 2 mm) e consistiu de uma fase de adaptação ao exercício e à vibração e após este período uma fase de treinamento. Para análise a região do osso selecionada foi o terço proximal da diáfise do fêmur. Como resultado, obtivemos que para o grupo SO a indução à osteoporose foi positiva quando comparada ao grupo S, que ...(Resumo completo, clicar acesso eletrônico abaixo)