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Souza, André Cristiano De [unesp] - One of the best experts on this subject based on the ideXlab platform.

  • Failure analysis of the drive shaft Bearing Bracket used in heavy vehicle
    Universidade Estadual Paulista (UNESP), 2014
    Co-Authors: Souza, André Cristiano De [unesp]
    Abstract:

    Este trabalho tem o objetivo principal de compreender a metodologia de especificação e análise de linha de transmissão de torque através de cardans / juntas universais e avaliar o quanto o resultado oriundo desta metodologia influenciou na falha do suporte do mancal do cardan em uma aplicação real. Foram realizadas três linhas de trabalhos distintas, primeiro foi compreendido toda a metodologia e realizado os cálculos analíticos de acelerações e cargas de mancais nos cardans / juntas universais, em segundo foi realizado cálculos estruturais via MEF – Método dos Elementos Finitos com vários tipos de carregamentos, incluindo os obtidos através dos cálculos analíticos, e como resposta foram gerados valores de tensões normais máximas e mínimas em função de cada carregamento. Os resultados de tensões via MEF foram comparados com as tensões resultantes da terceira linha de trabalho obtidas através da instrumentação de um suporte de mancal de cardan em campo durante a aplicação real do caminhão em análise. Os resultados geram a conclusão de que os carregamentos oriundos dos cálculos analíticos possuem muito pouca influência na falha do suporte do mancal do cardan e converge para as conclusões das linhas de pesquisas já iniciadas praticamente pela totalidade dos autores do estado da arte. Uma planilha de cálculo paramétrica foi desenvolvida no intuito de efetuar a análise com base na teoria / metodologia suportanto o projetista diminuindo o tempo de aprovação, mas é necessário a continuidade de linhas de pesquisas neste assunto no intuito de prever com maior precisão o comportamento dinâmico da aplicação de linhas de transmissão de torque através de cardans e juntas universaisUnderstand the methodology of specification and analysis of torque transmission line through cardan and universal joint and evaluate how much these results are influent in the gimbal Bearing Bracket failure in a real case is the most important objective of this job. Three distinct task lines were applied, first it was understood the entire methodology and performed all analytical calculations about accelerations and gimbal / universal joints Bearing loads. In second and parallel, it was performed structural calculations through the FEA – Finite Elements Method considering several loads including the load result acquired in previous step, and the results were explicit in stress. The results of maximum and minimum stresses for all loads of the second step were compared with results of field measures stress acquired by instrumentation of a new gimbal Bearing Bracket with extensometers sensors during a real application of a truck under analysis. All results generate the conclusion that loads from the analytical calculations have little influence in the gimbal Bearing Bracket failure and converge to the conclusions of the research lines already begun for almost authors all commented in the art state. A spreadsheet was created based on the current theory to support designers during the Project, minimizing the approval time, but is necessary the studies continuity in this assumption to predict with more precision the dynamic behavior of the application of torque transmission line through gimbals and universal joint

André Cristiano De ,souza - One of the best experts on this subject based on the ideXlab platform.

  • Análise da falha do suporte de mancal de um eixo cardan utilizado num veículo pesado
    Universidade Estadual Paulista (UNESP), 2014
    Co-Authors: André Cristiano De ,souza
    Abstract:

    Este trabalho tem o objetivo principal de compreender a metodologia de especificação e análise de linha de transmissão de torque através de cardans / juntas universais e avaliar o quanto o resultado oriundo desta metodologia influenciou na falha do suporte do mancal do cardan em uma aplicação real. Foram realizadas três linhas de trabalhos distintas, primeiro foi compreendido toda a metodologia e realizado os cálculos analíticos de acelerações e cargas de mancais nos cardans / juntas universais, em segundo foi realizado cálculos estruturais via MEF – Método dos Elementos Finitos com vários tipos de carregamentos, incluindo os obtidos através dos cálculos analíticos, e como resposta foram gerados valores de tensões normais máximas e mínimas em função de cada carregamento. Os resultados de tensões via MEF foram comparados com as tensões resultantes da terceira linha de trabalho obtidas através da instrumentação de um suporte de mancal de cardan em campo durante a aplicação real do caminhão em análise. Os resultados geram a conclusão de que os carregamentos oriundos dos cálculos analíticos possuem muito pouca influência na falha do suporte do mancal do cardan e converge para as conclusões das linhas de pesquisas já iniciadas praticamente pela totalidade dos autores do estado da arte. Uma planilha de cálculo paramétrica foi desenvolvida no intuito de efetuar a análise com base na teoria / metodologia suportanto o projetista diminuindo o tempo de aprovação, mas é necessário a continuidade de linhas de pesquisas neste assunto no intuito de prever com maior precisão o comportamento dinâmico da aplicação de linhas de transmissão de torque através de cardans e juntas universaisUnderstand the methodology of specification and analysis of torque transmission line through cardan and universal joint and evaluate how much these results are influent in the gimbal Bearing Bracket failure in a real case is the most important objective of this job. Three distinct task lines were applied, first it was understood the entire methodology and performed all analytical calculations about accelerations and gimbal / universal joints Bearing loads. In second and parallel, it was performed structural calculations through the FEA – Finite Elements Method considering several loads including the load result acquired in previous step, and the results were explicit in stress. The results of maximum and minimum stresses for all loads of the second step were compared with results of field measures stress acquired by instrumentation of a new gimbal Bearing Bracket with extensometers sensors during a real application of a truck under analysis. All results generate the conclusion that loads from the analytical calculations have little influence in the gimbal Bearing Bracket failure and converge to the conclusions of the research lines already begun for almost authors all commented in the art state. A spreadsheet was created based on the current theory to support designers during the Project, minimizing the approval time, but is necessary the studies continuity in this assumption to predict with more precision the dynamic behavior of the application of torque transmission line through gimbals and universal joint

Morić Matija - One of the best experts on this subject based on the ideXlab platform.

  • Sand casting simulation of aluminium alloy Bearing Bracket
    University of Zagreb. Faculty of Mechanical Engineering and Naval Architecture., 2020
    Co-Authors: Morić Matija
    Abstract:

    U ovom radu opisana je tehnologija lijevanja aluminijskih legura u jednokratne pješčane kalupe. Pojašnjeni su osnovni dijelovi uljevnog sustava, te njihov proračun pomoću nomograma. Opisan je proces skupljanja metala pri skrućivanju, te njegov utjecaj na izvedbu sustava za napajanje. Opisana je i uloga numeričkih simulacija u modernoj ljevačkoj industriji. U eksperimentalnom dijelu rada konstruirano je nekoliko varijanti uljevnog sustava za odljevak nosača ležaja te su uspoređeni rezultati dobiveni numeričkom simulacijom u programu QuikCAST s onima dobivenim lijevanjem u laboratoriju. Također je prikazan proces kalupljenja prilikom lijevanja u pješčane kalupe. Kod odljevaka lijevanih sa središnjim pojilom rezultati simulacije odgovaraju stvarnom stanju.This thesis describes the technology of casting aluminum alloys in sand molds. Elementary parts of the running system are described and their design using a nomogram is explained. In addition, the influence of volume contraction in metals during their solidification on the design of the feeding system is explained. The use of numerical simulations in the modern casting industry is also explained In the experimental part of the thesis, few variations of running systems were designed for the Bearing Bracket casting and the results of numerical simulations made using QuikCAST software were compared with the results of casting in the laboratory. The process of the production of sand molds is also presented. For castings with the central feeder, the simulation results match the actual condition

Perić Jure - One of the best experts on this subject based on the ideXlab platform.

  • Design of hydro generator upper combined Bearing Bracket
    University of Zagreb. Faculty of Mechanical Engineering and Naval Architecture., 2020
    Co-Authors: Perić Jure
    Abstract:

    U radu je prikazano konstruiranje i proračun nosača gornjeg kombiniranog ležaja. Opisane su vrste hidrogeneratora s obzirom na položaj vratila rotora te smještaj i glavne funkcije gornjeg nosača u vertikalnom hidrogeneratoru. Prikazana je položaj segmenata kombiniranog ležaja na tijelo gornjeg nosača te položaj i veličina radijalne i aksijalne sile koja djeluju na nosač. Opisano je tehnologično oblikovanja nosača i ležajnog lonca s aspekta postupka zavarivanja, strojne obrade i montaže svih dijelova koje je potrebno spojiti na nosač. Također, zbog manjih dimenzija transporta nosača, konstruirane su rastavljive ruke uporabom vijaka te je izračunato naprezanja u vijcima pomoću softvera za proračun vijčanih spojeva. Pomoću metode konačnih elemenata provedena je analiza naprezanja i pomaka za tri različita uvjeta rada hidrogeneratora a prethodno je dana verifikacija tetraedarskih paraboličnih konačnih elemenata. Na osnovu provedenog oblikovanja i proračuna napravljena je tehnička dokumentacija za rastavljivu i nerastavljivu izvedbu prema kojoj će nosač biti izrađen.This paper presents the construction and calculation of upper Bearing Bracket. Hydrogenerators, regarding position of the rotor shaft, and accommodation and main functions of the upper Bracket in vertical hydrogenerators, are described. The position of the segments of the combined Bearing on the upper support body is shown, also the position and size of the radial and axial forces acting on the carrier. Technological design of the Bracket and Bearing pot is described from the point of view of welding, machining and assembly of all the parts that will be connected to the Bracket. Also, due to the smaller dimensions of the Bracket carriage, disassembled hands were constructed using screws and, using software to calculate screw connections, the strain in screws was calculated. Analysis of stress and displacement for three different work conditions of the hydrogenerator was carried out with help of finite element method, but tetrahedral parabolic finite elements were verified before. On the basis of the design and calculating prepared the technical documentation for separable and inseparable embodiment for which the Bracket will be made

Gustavsson Rolf - One of the best experts on this subject based on the ideXlab platform.

  • Rotor dynamical modelling and analysis of hydropower units
    Luleå, 2008
    Co-Authors: Gustavsson Rolf
    Abstract:

    In almost all production of electricity the rotating machines serves as an important part of the energy transformation system. In hydropower units, a hydraulic turbine connected to a generator converts the potential energy stored in the water reservoir into electrical energy in the generator. An essential part of this energy conversion is the rotating system of which the turbine and the generator are crucial parts. During the last century the machines for production of electricity have been developed from a few megawatts per unit, up to several hundreds megawatts per unit. The development and increased size of the hydropower machines has also brought a need for new techniques. The most important developments are the increased efficiency of the turbines and generators, new types of Bearings and the introduction of new materials. Vibration measurement is still the most reliable and commonly used method for avoiding failure during commissioning, for periodic maintenance, and for protection of the systems. Knowledge of the Bearing forces at different operational modes is essential in order to estimate the degeneration of components and to avoid failures. In the appended Paper A, a method has been described for measurement of Bearing load by use of strain gauges installed on the guide Bearing Bracket. This technique can determine the magnitude and direction of both static and dynamic loads acting on the Bearing. This method also makes it possible to find the cause of the radial Bearing force among the various eccentricities and disturbances in the system. This method was used in Paper C to investigate Bearing stiffness and damping. A principal cause of many failures in large electrical machines is the occurrence of high radial forces due to misalignment between rotor and stator, rotor imbalance or disturbance from the turbine. In this thesis, two rotor models are suggested for calculation of forces and moments acting on the generator shaft due to misalignment between stator and rotor. These two methods are described in appended papers B and D. In Paper B, a linear model is proposed for an eccentric generator rotor subjected to a radial magnetic force. Both the radial force and the bending moment affecting the generator shaft are considered when the centre of the rotor spider hub deviates from the centre of the rotor rim. The magnetic force acting on the rotor is assumed to be proportional to the rotor displacement. In Paper D, a non-linear model is proposed for analysis of an eccentric rotor subjected to radial magnetic forces. Both the radial and bending moments affecting the generator shaft are considered when the centre of the generator spider hub deviates from the centre of the generator rim. The magnetic forces acting on the rotor are assumed to be a non-linear function of the air-gap between the rotor and stator. The stability analysis shows that the rotor can become unstable for small initial eccentricities if the position of the rotor rim relative to the rotor hub is included in the analysis. The analysis also shows that natural frequencies can decrease and the rotor response can increase if the position of the rotor rim in relation to the rotor spider is considered. In Paper E, the effect of damping rods was included in the analysis of the magnetic pull force. The resulting force was found to be reduced significantly when the damper rods were taken into account. An interesting effect of the rotor damper rods was that they reduced the eccentricity forces and introduced a force component perpendicular to the direction of eccentricity. The results from the finite-element simulations were used to determine how the forces affect the stability of the generator rotor. Damped natural eigenfrequencies and the damping ratio for load and no-load conditions were investigated. When applying the forces computed in the time- dependent model, the damped natural eigenfrequencies were found to increase and the stability of the generator rotor was found to be reduced, compared with when the forces were computed in a stationary model. Damage due to contact between the runner and the discharge ring have been observed in several hydroelectric power units. The damage can cause high repair costs to the runner and the discharge ring as well as considerable production losses. In Paper F a rotor model of a 45 MW hydropower unit is used for the analysis of the rotor dynamical phenomena occurring due to contact between the runner and the discharge ring for different grades of lateral force on the turbine and Bearing damping. The rotor model consists of a generator rotor and a turbine, which are connected to an elastic shaft supported by three isotropic Bearings. The discrete representation of the rotor model consist of 32 degrees of freedom. To increase the speed of the analysis, the size of the model has been reduced with the IRS method to a system with 8 degrees of freedom. The results show that a small gap between the turbine and discharge ring can be dangerous, due to the risk of contact with high contact forces as a consequence. It has also been observed that backward whirl can occur and in some cases the turbine motion becomes quasi-periodic or chaotic. The endurance of hydropower rotor components is often associated with the dynamic loads acting on the rotating system and the number of start-stop cycles of the unit. Measurements, together with analysis of the rotor dynamics, are often the most powerful methods available to improve understanding of the cause of the dynamic load. The method for measurement of the Bearing load presented in this thesis makes it possible to investigate the dynamic as well as the static loads acting on the Bearing Brackets. This can be done using the suggested method with high accuracy and without re-designing the Bearings. During commissioning of a hydropower unit, measurement of shaft vibrations and forces is the most reliable methods for investigating the status of the rotating system. Generator rotor models suggested in this work will increase the precision of the calculated behaviour of the rotor. Calculation of the rotor behaviour is important before a generator is put in operation, after overhaul or when a new machine is to be installed.Godkänd; 2008; 20081111 (ysko)

  • Modelling and analysis of hydropower generator rotors
    Luleå, 2005
    Co-Authors: Gustavsson Rolf
    Abstract:

    In almost all production of electricity the rotating machines serves as an important part of the energy transformation system. In hydropower units, a hydraulic turbine connected to a generator converts the potential energy stored in the water reservoir into electrical energy in the generator. An essential part of this energy conversion is the rotating system of which the turbine and the generator are part. During the last century the machines for electricity production have been developed from a few mega watts per unit up to several hundreds mega watts per unit. The development and increasing of size of the hydropower machines have also brought a need for new techniques. The most important developments are the increased efficiency of the turbines and generators, new types of Bearings and the introduction of new materials. Vibration measurements are still the most reliable and commonly used method to avoid failure during commissioning, for periodic maintenance, and as protection of the systems. Knowledge of the Bearing forces in different operational modes is essential in order to estimate the degeneration of components and to avoid failures. In the appended Paper A, a method has been described for measurement of Bearing load by use of strain gauges installed on the guide Bearing Bracket. This technique can determine the magnitude and direction of both static and dynamic loads acting on the Bearing. This method also makes it possible to find the cause of the radial Bearing force among the various eccentricities and disturbances in the system. A principal cause of many failures in large electrical machines is the occurrence of high radial forces due to misalignment between rotor and stator, rotor imbalance or disturbance from the turbine. In this thesis, two rotor models are suggested for calculation of forces and moments acting on the generator shaft depending on misalignment between stator and rotor. These two methods are described in appended papers B and C. In Paper B, a linear model is proposed for an eccentric generator rotor subjected to a radial magnetic force. Both the radial force and the bending moment affecting the generator shaft are considered when the centre of the rotor spider hub deviates from the centre of the rotor rim. The magnetic pull force acting on the rotor is assumed to be proportional to the rotor displacement. In Paper C, a non-linear model is proposed for analysis of an eccentric rotor subjected to radial magnetic force. Both the radial and bending moments affecting the generator shaft are considered when the centre of the generator spider hub deviates from the centre of the generator rim. The magnetic forces acting on the rotor are assumed to be a non-linear function of the air-gap between the rotor and stator. The stability analysis shows that the rotor can become unstable for small initial eccentricities if the rotor rim position relative to the rotor hub is included in the analysis. The analysis also shows that the natural frequencies can decrease and the rotor response can increase if the rotor rim position in relation to the rotor spider is considered. The endurance of hydropower rotor components is often associated with the dynamic loads acting on the rotating system and the number of start-stop cycles of the unit. Measurements together with analysis of the rotordynamics are often the most powerful methods available to improve understanding of the cause of the dynamic load. The method for measurement of Bearing load presented in this thesis makes it possible to investigate the dynamic as well as the static loads as acting on the Bearing Brackets. This can be done using the suggested method with high accuracy and without redesign of the Bearings. During commissioning of hydropower unit, measurements of shaft vibrations and forces are the most reliable method to investigate the status of the rotating system. Generator rotor models suggested in this work will increase the precision of the calculated behavior of the rotor. Calculation of the rotor behavior is important before the generator is put in operation, after rehabilitation or when new machines will be installed.Godkänd; 2005; 20061214 (haneit