• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 7
  • 7
  • 2
  • 1
  • Tagged with
  • 20
  • 8
  • 8
  • 7
  • 7
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Aplicação do método de análise de risco ao estudo do descarrilamento. / Aplication of risk analysis method to the derailment study.

William Hong 01 April 2011 (has links)
Este trabalho propõe um método de análise de risco aplicada ao descarrilamento (incidente no qual a roda perde a sustentação provida pelo trilho, podendo ser causado por diversos aspectos como imperfeições na via, falhas no material rodante, obstáculos na via, entre outras que pode acarretar possíveis acidentes e perdas materiais e humanas) de forma a tornar mais seguro o transporte ferroviário, que atualmente não apresenta diminuição da taxa de ocorrência dos descarrilamentos, complementando assim as simulações computacionais e simulações dinâmicas que podem ser aplicadas ao estudo deste evento. Risco pode ser definido como o potencial de perda resultante da exposição a um perigo, sendo relacionado à probabilidade de ocorrência de um evento ou combinação de eventos acarretando em um perigo e a conseqüência deste perigo. Este conceito pode ser utilizado para investigar e avaliar as incertezas associadas com um evento. Já Confiabilidade pode ser definida como a probabilidade de um item executar a sua função sob condições pré-definidas de uso e manutenção por um período de tempo específico. Assim, considerando estes dois conceitos, será apresentada uma metodologia de análise de risco e confiabilidade para análise e discussão do descarrilamento, discorrendo sobre os possíveis parâmetros que podem causar este evento bem como propondo uma alternativa para avaliação da probabilidade de ocorrência do descarrilamento; desta forma permite guiar o gerenciamento da segurança quanto a este evento já que no Brasil não existe a figura da autoridade ferroviária, órgão máximo e responsável final pela regulamentação para a operação de um sistema ferroviário, que poderia determinar o processo que deve ser seguido para a garantia de segurança. Os objetos de estudo serão veículos ferroviários e conseqüentemente os elementos de interface com este tipo de veículo, como por exemplo, os elementos de via. / This research proposes a risk analysis method applied to derailment event (characterized by the wheel overlap on the rail, which can be caused by many aspects: rail imperfections, rolling stock failures, obstacles etc and which can cause accidents, material and life loss) to increase the safety level on railway transport that actually does not present decrease of derailment rate. This method also complements computational and dynamic simulations, which can be applied to this event. Risk can be defined as the potential loss due to a hazard exposure, also related with the probability of occurrence of an event or combinations of events leading to a hazard and the consequence of this hazard. This concept can be applied to investigate and to evaluate the uncertainties related with this event. Reliability can be defined as the probability of an item to perform its function under predefined use and maintenance conditions during a specific period of time. Thus, considering these two concepts, it will be presented a risk and reliability analysis to study the derailment event, discoursing about the possible parameters that can cause this event and proposing alternatives to evaluate the derailment occurrence probability in order to guide safety management since a railway authority does not exist in Brazil (body with the overall accountability to a regulator for operation a railway system, that could determines the process to be followed to assure safety levels). This research will cover railway vehicles and consequently the interface, for example, the railroad elements.
12

Avaliação dinâmica de veículos ferroviários através de um sistema multicorpos / Dynamic assessment of railway vehicles through a multibody system

Viganico, Carlos Eduardo Henke January 2010 (has links)
Os acidentes com veículos ferroviários podem ter origem em muitos fatores, mas os principais são relacionados com a dinâmica do veículo e carga, via permanente em péssimas condições e operações inseguras nos trens. Os acidentes causam mortes, danos materiais e ao meio ambiente e prejuízos para as operadoras e seus clientes. Para avaliar a dinâmica dos veículos ferroviários, um sistema multicorpos foi desenvolvido (programa computacional) para representar matematicamente um típico veículo ferroviário com seus principais graus de liberdade. As equações de movimento foram desenvolvidas utilizando a equação de Lagrange de movimento, a qual considera princípios da mecânica como: energia cinética, energia potencial e a dissipação de energia do sistema. As equações acopladas e desacopladas são programadas e resolvidas para acelerações, estas são integradas duas vezes, obtendo-se as velocidades e deslocamentos. A partir das repostas do sistema o comportamento do veículo pode ser avaliado em várias condições de operação. A verificação do programa é realizada através de comparações com resultados de outros programas publicados na literatura, onde se verifica uma adequada correlação. Avaliações nos principais regimes de operação são realizadas de forma a simular condições determinadas pela norma AAR e condições extras originadas por irregularidades aperiódicas da via do tipo cusp e jog. Dois tipos de veículos são simulados para representar as condições típicas das ferrovias brasileiras: veículos operando em bitola métrica e em bitola larga. Os resultados das simulações apresentam valores de amplitude e fase que estão de acordo com resultados expostos nas normas e na literatura ferroviária de referência utilizada neste trabalho. A avaliação dinâmica de veículos ferroviários através de um programa computacional é importante, pois considera as principais características dos veículos e via permanente. A possibilidade de representar o veículo com uma configuração simples em relação a programas comerciais permite uma simulação rápida e confiável para determinar respostas em regimes como: hunting, twist e roll, pitch e bounce e yaw e sway. / The accidents with rail vehicles has origin due to many factors, but the main ones are related to the dynamics of the vehicle and load, the spoiled railway and unsafe operations on the trains. Accidents causing deaths, damage to property and the environment and damage to operators and their customers. In order to evaluate the railway vehicles dynamics, it was developed a multibody system (computer program) to mathematically represent a typical railway vehicle with its main degrees of freedom. The motion equations were developed using Lagrange's equation of motion, which takes into consideration the principles of mechanical, as: kinetic energy, potential energy and energy dissipation of the system. The coupled and uncoupled equations are programmed and solved for accelerations, which are twice integrated, in order to have the speeds and displacements. From the system’s responses, the vehicle behavior can be evaluated in several operating conditions. The comparison of the program is accomplished through confrontations with results from other programs in the literature, in which a good correlation is verified. The evaluations in the main regimes of operation are made in a way simulate the conditions determined by the standard conditions and extra conditions caused by aperiodic irregularities of the track. Two types of vehicles are simulated to represent the typical conditions of Brazilian railways: vehicles operating on meter gauge and large gauge. The simulation results show that amplitude and phase values are consistent with results presented in the standards and in the railway literature of reference of this work. The rail vehicles dynamic evaluation through a computer program was important because it considers the main characteristics of vehicles and permanent way. The possibility of representing the vehicle with a simple configuration in relation to commercial softwares allows a fast and reliable simulation to determine responses in regimes as: hunting, twist and roll, pitch and bounce and yaw and sway.
13

Avaliação dinâmica de veículos ferroviários através de um sistema multicorpos / Dynamic assessment of railway vehicles through a multibody system

Viganico, Carlos Eduardo Henke January 2010 (has links)
Os acidentes com veículos ferroviários podem ter origem em muitos fatores, mas os principais são relacionados com a dinâmica do veículo e carga, via permanente em péssimas condições e operações inseguras nos trens. Os acidentes causam mortes, danos materiais e ao meio ambiente e prejuízos para as operadoras e seus clientes. Para avaliar a dinâmica dos veículos ferroviários, um sistema multicorpos foi desenvolvido (programa computacional) para representar matematicamente um típico veículo ferroviário com seus principais graus de liberdade. As equações de movimento foram desenvolvidas utilizando a equação de Lagrange de movimento, a qual considera princípios da mecânica como: energia cinética, energia potencial e a dissipação de energia do sistema. As equações acopladas e desacopladas são programadas e resolvidas para acelerações, estas são integradas duas vezes, obtendo-se as velocidades e deslocamentos. A partir das repostas do sistema o comportamento do veículo pode ser avaliado em várias condições de operação. A verificação do programa é realizada através de comparações com resultados de outros programas publicados na literatura, onde se verifica uma adequada correlação. Avaliações nos principais regimes de operação são realizadas de forma a simular condições determinadas pela norma AAR e condições extras originadas por irregularidades aperiódicas da via do tipo cusp e jog. Dois tipos de veículos são simulados para representar as condições típicas das ferrovias brasileiras: veículos operando em bitola métrica e em bitola larga. Os resultados das simulações apresentam valores de amplitude e fase que estão de acordo com resultados expostos nas normas e na literatura ferroviária de referência utilizada neste trabalho. A avaliação dinâmica de veículos ferroviários através de um programa computacional é importante, pois considera as principais características dos veículos e via permanente. A possibilidade de representar o veículo com uma configuração simples em relação a programas comerciais permite uma simulação rápida e confiável para determinar respostas em regimes como: hunting, twist e roll, pitch e bounce e yaw e sway. / The accidents with rail vehicles has origin due to many factors, but the main ones are related to the dynamics of the vehicle and load, the spoiled railway and unsafe operations on the trains. Accidents causing deaths, damage to property and the environment and damage to operators and their customers. In order to evaluate the railway vehicles dynamics, it was developed a multibody system (computer program) to mathematically represent a typical railway vehicle with its main degrees of freedom. The motion equations were developed using Lagrange's equation of motion, which takes into consideration the principles of mechanical, as: kinetic energy, potential energy and energy dissipation of the system. The coupled and uncoupled equations are programmed and solved for accelerations, which are twice integrated, in order to have the speeds and displacements. From the system’s responses, the vehicle behavior can be evaluated in several operating conditions. The comparison of the program is accomplished through confrontations with results from other programs in the literature, in which a good correlation is verified. The evaluations in the main regimes of operation are made in a way simulate the conditions determined by the standard conditions and extra conditions caused by aperiodic irregularities of the track. Two types of vehicles are simulated to represent the typical conditions of Brazilian railways: vehicles operating on meter gauge and large gauge. The simulation results show that amplitude and phase values are consistent with results presented in the standards and in the railway literature of reference of this work. The rail vehicles dynamic evaluation through a computer program was important because it considers the main characteristics of vehicles and permanent way. The possibility of representing the vehicle with a simple configuration in relation to commercial softwares allows a fast and reliable simulation to determine responses in regimes as: hunting, twist and roll, pitch and bounce and yaw and sway.
14

Análise de segurança de veículo ferroviário de carga em tangente considerando a excitação periódica da via permanente. / Safety analysis of a ralway car in tangent considering the periodic excitation of the permanent way.

Guilherme Fabiano Mendonça dos Santos 27 March 2015 (has links)
Uma ocorrência ferroviária tem danos imprevisíveis, desde um simples atraso do horário do trem enquanto o socorro ferroviário encarrilha o vagão, até prejuízos milionários com grande perda de ativos (material rodante e via permanente) e, em casos extremos, até vidas humanas. Portanto, as ferrovias nacionais sempre buscam maneiras de programar ações que minimizam este risco. Uma das principais ações é estabelecer critérios de manutenção sempre justos. Entretanto, estes critérios geralmente não contemplam de maneira conjunta a dinâmica veicular e a geometria da via permanente. Neste sentido, este trabalho elabora um modelo matemático de um vagão ferroviário de alta capacidade em conjunto com a flexibilidade do suporte da via permanente. O modelo matemático foi validado e considerado satisfatório, a partir da comparação das frequências naturais obtidas no vagão real e na comparação de seu resultado produzido a partir de uma entrada medida com equipamentos de controle de geometria de linha e de medições dinâmicas realizadas por vagão instrumentado. Um método estratégico para análise da segurança do veículo foi sugerida e utilizada mostrando-se capaz de determinar os comprimentos de onda da via permanente que devem ser priorizados na manutenção, bem como na análise da segurança do vagão quando na adoção de restrições de velocidades. / A railway derailment is usually an unpredictable, damage from a simple train delay of to a big goods loss of assets (rolling stock and permanent way) and, in extremely cases, even human lives. Therefore, the Brazilians railways are always implementing actions that minimize this risk of a derailment. One of the main actions is to establish tight maintenance criteria. However, these usually do not consider the vehicle dynamics and the geometry of the permanent way together. Thus, this paper develops a mathematical model of a high capacity railcar together with the flexibility of the support of the permanent way. The mathematical model was validated and considered satisfactory, by comparing the natural frequencies obtained between the model and a real vehicle tested in the field. In addition, the model results were compared against filed measurements of an instrumented wagon and a track geometric data. A strategic method to analysis the operational safety analysis was suggested and used proving to be able to determine the wavelength of the permanent way that should be prioritized in the maintenance action as well as when adopting speed restriction.
15

Avaliação dinâmica de veículos ferroviários através de um sistema multicorpos / Dynamic assessment of railway vehicles through a multibody system

Viganico, Carlos Eduardo Henke January 2010 (has links)
Os acidentes com veículos ferroviários podem ter origem em muitos fatores, mas os principais são relacionados com a dinâmica do veículo e carga, via permanente em péssimas condições e operações inseguras nos trens. Os acidentes causam mortes, danos materiais e ao meio ambiente e prejuízos para as operadoras e seus clientes. Para avaliar a dinâmica dos veículos ferroviários, um sistema multicorpos foi desenvolvido (programa computacional) para representar matematicamente um típico veículo ferroviário com seus principais graus de liberdade. As equações de movimento foram desenvolvidas utilizando a equação de Lagrange de movimento, a qual considera princípios da mecânica como: energia cinética, energia potencial e a dissipação de energia do sistema. As equações acopladas e desacopladas são programadas e resolvidas para acelerações, estas são integradas duas vezes, obtendo-se as velocidades e deslocamentos. A partir das repostas do sistema o comportamento do veículo pode ser avaliado em várias condições de operação. A verificação do programa é realizada através de comparações com resultados de outros programas publicados na literatura, onde se verifica uma adequada correlação. Avaliações nos principais regimes de operação são realizadas de forma a simular condições determinadas pela norma AAR e condições extras originadas por irregularidades aperiódicas da via do tipo cusp e jog. Dois tipos de veículos são simulados para representar as condições típicas das ferrovias brasileiras: veículos operando em bitola métrica e em bitola larga. Os resultados das simulações apresentam valores de amplitude e fase que estão de acordo com resultados expostos nas normas e na literatura ferroviária de referência utilizada neste trabalho. A avaliação dinâmica de veículos ferroviários através de um programa computacional é importante, pois considera as principais características dos veículos e via permanente. A possibilidade de representar o veículo com uma configuração simples em relação a programas comerciais permite uma simulação rápida e confiável para determinar respostas em regimes como: hunting, twist e roll, pitch e bounce e yaw e sway. / The accidents with rail vehicles has origin due to many factors, but the main ones are related to the dynamics of the vehicle and load, the spoiled railway and unsafe operations on the trains. Accidents causing deaths, damage to property and the environment and damage to operators and their customers. In order to evaluate the railway vehicles dynamics, it was developed a multibody system (computer program) to mathematically represent a typical railway vehicle with its main degrees of freedom. The motion equations were developed using Lagrange's equation of motion, which takes into consideration the principles of mechanical, as: kinetic energy, potential energy and energy dissipation of the system. The coupled and uncoupled equations are programmed and solved for accelerations, which are twice integrated, in order to have the speeds and displacements. From the system’s responses, the vehicle behavior can be evaluated in several operating conditions. The comparison of the program is accomplished through confrontations with results from other programs in the literature, in which a good correlation is verified. The evaluations in the main regimes of operation are made in a way simulate the conditions determined by the standard conditions and extra conditions caused by aperiodic irregularities of the track. Two types of vehicles are simulated to represent the typical conditions of Brazilian railways: vehicles operating on meter gauge and large gauge. The simulation results show that amplitude and phase values are consistent with results presented in the standards and in the railway literature of reference of this work. The rail vehicles dynamic evaluation through a computer program was important because it considers the main characteristics of vehicles and permanent way. The possibility of representing the vehicle with a simple configuration in relation to commercial softwares allows a fast and reliable simulation to determine responses in regimes as: hunting, twist and roll, pitch and bounce and yaw and sway.
16

On the Influence of Rail Vehicle Parameters on the Derailment Process and its Consequences

Brabie, Dan January 2005 (has links)
This thesis aims at systematically studying the possibilities of minimising devastatingconsequences of high-speed derailments by appropriate measures and features in thetrain design, including the running gear. The course of events immediately afterderailments is studied with respect to whether the train stays upright and close to thetrack centre line or deviates laterally with probably serious consequences. There is abelief in the railway community that some trains can better cope with derailment thenothers, although this superiority is apparently hard to quantify.Firstly, an empirical database has been established containing as much relevantinformation as possible of past incidents and accidents occurred at higher speeds due tomechanical failure close to the interface between the running gear and the track, as wellas other causes that ultimately brought the train into a derailed condition. Although nevertwo derailments are the same, certain patterns appeared to crystallise after analysing thecourse of events immediately after the failure based on the descriptions available in eachincident or accident report. Ultimately, this led to that several critical vehicle parameterscould be distinguished as capable to influence the outcome of a derailment.Secondly, two of the critical vehicle features found in the first stage have been subject todetailed analysis by means of multi-body system (MBS) simulations. The first phase ofthe computer simulation program focused on studying the tendency of a wheelset toderail as a result of an axle journal failure on the outside of the wheel. The prederailmentcomputer simulation model has been validated with good results for twoauthentic Swedish events of axle journal failure.Thereafter, one of the newly found critical vehicle feature, the wheelset mechanicalrestrictions relative to the bogie frame, have been extensively studied on an X 2000power unit and trailer car model. The results show that a vertical mechanical restrictionof the wheelset relative to the bogie frame of approximately 50 to 60 mm is capable ofkeeping the wheelsets on the rails after an axle journal failure, for the studied conditions.An axle mounted brake disc constitutes the second critical vehicle feature that has thepotential to favourably influence the sequence of events in cases of wheel flangeclimbing. A minimal range of geometrical parameters for which the rail would safely fillthe gap between the brake disc and the wheel has been calculated.The third and last part of the thesis establishes the prerequisites necessary in order tostudy the remaining of the critical vehicle parameters found in the first part, whichrequires complete MBS simulations of derailed vehicles rolling on track structures, i.e.concrete sleepers. To accomplish this task, hysteresis data for the force as function ofconcrete material indentation, are aimed to be acquired by means of finite element (FE)simulations. Therefore, the intended FE model of wheel-concrete sleeper impact issubjected to a tentative validation procedure. A good agreement is observed whencomparing the FE model results with an authentic accident in terms of concrete sleeperindentation. Furthermore, preliminary results in terms of a wheelset tendency to reboundafter concrete sleeper impact are presented. / QC 20101125
17

On Derailment-Worthiness in Rail Vehicle Design : Analysis of vehicle features influencing derailment processes and consequences

Brabie, Dan January 2007 (has links)
This thesis aims at systematically studying the possibilities of minimizing devastating consequences of high-speed rail vehicle derailments by appropriate measures and features in the train design including the running gear. Firstly, an empirical database is established containing as much relevant information as possible of past incidents and accidents that have occurred at substantial running speeds due to mechanical failure close to the interface between the running gear and the track. Other causes that ultimately brought the train in a derailed condition are also covered. Although various accidental circumstances make each derailment a unique event, certain patterns appear to emerge which lead to several critical vehicle parameters capable of influencing the outcome of a derailment or preventing a derailment to occur. Secondly, the possibility of preventing wheel climbing derailments after an axle journal failure is studied by implementing mechanical restrictions between wheelsets and bogie frame. In this respect, a multi body system (MBS) computer model is developed to account for such an axle failure condition, which is successfully validated on the basis of two authentic passenger car events. In order to study the overall post-derailment vehicle behaviour, in particular the wheelsets’ vertical motion and lateral deviation on sleepers, a comprehensive MBS post-derailment module is developed and implemented in the commercially available software GENSYS. The model detects wheel-sleeper impact conditions and applies valid force resultants calculated through linear interpolation based on a pre-defined look-up table. The table was constructed through exhaustive finite element (FE) wheel to concrete sleeper impact simulations utilising the commercially available software LS-DYNA. The MBS post-derailment module has been validated successfully in several stages, including a correct prediction of the derailing wheelset’s trajectory over ten consecutive sleepers in comparison with an authentic passenger vehicle derailment event. An extensive simulation analysis on the feasibility of utilizing alternative substitute guidance mechanisms attached to the running gear on rail vehicles is presented, as means of minimizing the lateral deviation. Three low-reaching guidance mechanisms attached onto the running gear (bogie frame, brake disc and axle journal box) are analysed in terms of geometrical parameters for a successful engagement with the rail in order to prevent large lateral deviations after twelve different derailment scenarios. Three conventional coupled passenger trailing cars are investigated in terms of lateral deviation and vehicle overturning tendency after derailments on tangent and curved track. This is performed as a function of various vehicle design features and parameters such as: maximum centre coupler yaw angle, carbody height of centre of gravity, coupler height and additional running gear features. In a similar manner, the articulated train concept is investigated in terms of the post-derailment vehicle behaviour as a function of different inter-carbody damper characteristics and running gear features. / QC 20100701
18

Modeling Mild Thermal Cracking of Heavy Crude Oil and Bitumen with VLE Calculations

Guerra, André 20 August 2018 (has links)
The current shortage of crude oil from conventional sources has increased interest in developing unconventional resources such as oil sands. Heavy crudes and bitumen are found in Northern Alberta and their exploration, processing, and transport to market pose challenges in the use of these resources. Part of the solution to these challenges involves the reactive thermal processing of heavy crudes and bitumen. This thesis focused on mild thermal cracking reactions, and two studies regarding these reactions were presented. The first was an experimental study performed in a pilot-scale semi-batch reactor. The three crude oils were heated to 350, 400, 425, and 450°C at 1240 kPa. A five-lump reaction model combined with a process simulator with VLE calculations was fitted with the experimental data obtained. The goodness of fit between the model predicted values and experimental values for the Hardisty (MBL), Albian Heavy Synthetic (AHS), and Christina Lake Dilute Bitumen (CDB) were determined to be 0.99, 0.99, and 0.98, respectively. Moreover, 80, 85, and 89% of the optimized model’s predicted values had less than 10% error for MBL, AHS, and CDB, respectively. The second study described the implementation of a mild thermal cracking reaction model to the development of a train car fire-model for the assessment of safety aspects in the design of train cars used to transport crude oil. Case studies were conducted using the UniSim® depressuring utility and a previously developed mild thermal cracking reaction model to demonstrate the effect of compositional change. Three crude oils with varying properties and representative of the types of crudes transported by rail in Canada were used here: MBL, AHS, and CDB. The case studies conducted showed the performance of a train car fire-model to be dependent on the crude oil characteristics: up to -57% and -99% difference in model predicted variables for AHS and CDB, respectively, when compared to MBL. Furthermore, the model’s performance was also shown to be affected by the compositional change of a given crude oil due to mild thermal cracking reactions: up to 42% difference in model predicted variables when compared to the base case.
19

Kolmá křížení tramvajových tratí s vlečkami / Perpendicular crossings tram tracks with railway sidings

Omaník, David January 2018 (has links)
The diploma thesis deals with the perpendicular crossing of tram track with railway siding. The structure of crossing is described both in the Czech Republic and in the world. The aim of the thesis is to find the recommended design solution for the crossing of tram and railway tracks with regard to legislation and feasibility. After a comparison of the existing structures is chosen which satisfies the conditions of feasibility.
20

Požadavky na projektovaný a provozní stav geometrických parametrů koleje ve vztahu k vzájemnému působení vozidla a koleje / Requirements for design and in servce quality of track geometry in relation to interatcion between vehicle and track

Trejtnar, Radek Unknown Date (has links)
Aim of the proper track design is build track, which enable smooth run of the vehicle as much as is possible complying with the safety rules and reasonable level of comfort for passengers. However, this track has to be maintainable and the vehicle shouldn’t face unacceptable amount of wear. On the other hand it is clear that it is impossible to build ideal (straight) track because of many environmental and morphological conditions. So the rules for track designing have to be set carefully in order to produce a good track design which meets the conditions mentioned above. The principles for track designing are evaluated with using the results of track test running dynamic behavior of the vehicles in this study. These tests were made for couple vehicles on several track sections. The influence of design parameters on the dynamic behavior are evaluated based on these results. That’s defining one of the basic part interactions between vehicle and track. Evaluation of the quality of track geometry in service has the same or may be higher importance. Limit values as defined in standard ČSN 73 6360-2 was set partially in consideration results of scientific studies, but partially in consideration of as common practice. So that part of this work is verification of the influence of tolerance in each parameter and their combinations in order to allow reasonable establishment of their limit values for track maintenance and for preventing of train derailment.

Page generated in 0.4677 seconds