Zugl.: Berlin, Freie Univ., Diss., 2008

Thesis (B. LITT.)--Oxford. / Without thesis statement. Bibliography: p. 170-174.

Zugl.: Berlin, Freie Universiẗat, Diss., 2008.

Techn. Universiẗat, Diss., 2005--München.

Thesis (M.A. in Security Studies (Civil-Military Relations)--Naval Postgraduate School, March 2005. / Thesis Advisor(s): Donald Abenheim. Includes bibliographical references (p. 93-94). Also available online.

München, Techn. Univ., Diss., 2004.

Zugl.: Passau, Universiẗat, Diss., 2004.

Theoretical models, such as TWINS, and microphone array measurements have been widely used to gain better understanding of rolling noise. However, the array measurements are often inconsistent with the TWINS predictions and give less prominence to the rail than the theoretical models. The objectives of this thesis are to make validation work of the TWINS model for Japanese railway lines, and to explore the reason why the microphone array gives a correct estimate of sound power radiated by the rail. A comparison in terms of noise and rail vibration has been carried out for six wheel/rail conditions of Japanese railways. The TWINS predictions show good agreement with the measurements. After confirming the applicability of the TWINS model, the effects of wheel load on noise and rail vibration are investigated, and the predictions show similar trends to the measurements. The acoustic properties of a rail as measured with a microphone array have been investigated through simulations and field tests. In the simulation the rail is modelled as an array of multiple sources. Results are given for two situations: (a) the multiple sources are incoherent, which is assumed in determining sound power from a microphone array, (b) the sources are coherent, which is more representative of the rail radiation. It is found that the microphone array cannot detect a large part of the noise generated by the rail in the frequency range where free wave propagation occurs. Sound measurements were carried out to validate the radiation model of the rail by using a shaker excitation of a track. It is found that the noise is radiated from the rail at an angle to the normal when free wave propagation occurs in the rail, and that the predictions based on coherent sources show good agreement with the measurements. Sound measurements for a moving train were also performed with a microphone array. It is shown that the microphone array misses a large part of noise generated by the rail, when directed normal to the rail. This leads to an underestimation of the rail component of the noise in the array measurements.

No description available.

Parcela expressiva do transporte de cargas e de passageiros é realizada atualmente no Brasil pelo modo rodoviário, sendo que mais de 90% da malha viária federal é composta por rodovias bidirecionais com duas faixas de tráfego. A necessidade de manobras de ultrapassagem neste tipo de rodovia é bastante comum e a falta de oportunidades para que elas se realizem pode comprometer a eficiência operacional e condições gerais e específicas de segurança ao longo da via. O principal parâmetro de projeto relacionado às manobras de ultrapassagem é a Distância de Visibilidade de Ultrapassagem (DVU). Hoje há critérios distintos para a fixação dos valores mínimos de projeto para este parâmetro: a DVU dimensionada pelo critério geométrico é aplicada no desenvolvimento do projeto de geometria da rodovia e a DVU dimensionada pelo critério de sinalização é utilizada no projeto de sinalização da via. Os valores mínimos de DVU recomendados diferem bastante de um critério para outro, assim como as considerações pertinentes ao dimensionamento dos mesmos. No Brasil as referências para os valores estabelecidos são o Manual de Projeto Geométrico de Rodovias Rurais e o Manual de Sinalização Rodoviária, ambos publicados em 1999 pelo extinto DNER (atual DNIT). Quando se considera, por um lado, que as metodologias para estabelecimento dos mencionados valores mínimos são fundamentadas em estudos e pesquisas de campo realizados nos Estados Unidos na primeira metade do século passado e, por outro lado, o avanço das características técnicas das rodovias e dos veículos em circulação bem como as alterações ocorridas no comportamento dos motoristas ao longo das últimas décadas, torna-se evidente a necessidade de revisão de tais metodologias. Considerando sua aplicação às rodovias brasileiras, julga-se conveniente o desenvolvimento de pesquisas sobre a realização de manobras de ultrapassagens na malha viária nacional, com o objetivo de verificar se os valores da DVU atualmente em uso são adequados. Neste sentido, este trabalho apresenta uma análise crítica dos principais modelos e critérios hoje adotados no país e no Exterior, com base em ampla pesquisa bibliográfica e no levantamento de dados relacionados a manobras de ultrapassagem observadas em três rodovias do Estado de São Paulo, assim como a proposição de modelos alternativos para a definição de valores mínimos para a DVU segundo o critério geométrico e o critério de sinalização. / Today, most of the transportation in Brazil – of both people and goods - uses the country’s highway system. Two-lane highways represent over 90% of the federal highway network. Passing maneuvers are often required on such highways and the lack of opportunities may compromise operational efficiency and safety conditions. Passing Sight Distance (PSD) is the key project parameter related to passing maneuvers. Today, there are two different methods to establish minimum PSD design values: the geometric criteria, which are used highway on geometric design, and the signaling criteria, used to mark pavement surface. Minimum PSD values recommended by geometric criteria and signaling criteria are often very different, as well as the assumptions on which these models are based. In Brazil the references adopted are the Highway Design Manual for Rural Highways (Manual de Projeto Geométrico de Rodovias Rurais) and the Highway Signaling Manual (Manual de Sinalização Rodoviária), both published in 1999 by DNER (today called DNIT). Considering that the recommended values are based on field studies carried out in the United States in the first half of the 20th century, it is clear that these criteria must be reviewed, specially taking into account the technical advances of highways and vehicles, as well as the changes occurred in driving behavior over the last decades. Considering the application to Brazilian highways, it is important to research passing maneuvers through national roads in order to verify the adequacy of PSD values adopted. Therefore, this work presents a critical analysis of major models used today in Brazil and abroad, based on extensive bibliographical research and on field studies related to passing maneuvers in three highways in São Paulo State. New models to determine minimum PSD values are also proposed for both geometric and signaling criteria.