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International Journal of Railway Technology
IJRT, Volume 6, Issue 2, 2017
Vertical vs. Lateral Dynamic Behaviour of Soft Catenaries subject to Regular Loading using Field Measurements
A. Rønnquist and P. Nåvik
Department of Structural Engineering NTNU, Norwegian University of Science and Technology Trondheim, Norway
A. Rønnquist, P. Nåvik, "Vertical vs. Lateral Dynamic Behaviour of Soft Catenaries subject to Regular Loading using Field Measurements", International Journal of Railway Technology, 6(2), 39-59, 2017. doi:10.4203/ijrt.6.2.3
Keywords: soft catenary system, operational modal analysis, short-time Fourier analysis, pantograph–catenary interaction, dynamic monitoring, wireless monitoring, field measurements, dynamic assessment.
During the last couple of decades, there has been a steady increase in the development of higher-speed railways. Higher speeds increase the demands on existing railway infrastructure designed for older and different scenarios. This increase in demand is also true for the power supply of electric railways, in which a two-level catenary system is commonly used. Current, soft catenary systems are characterized by their design for optimal quasi-static behaviour. To modify and further develop catenary systems, it is important to have a solid overview of the dynamic characteristics. This paper further investigates the implications of using lateral response compared with the previous vertical response. It is clear that there are dynamic processes that both directions have in common; equally, the two also show quite substantial differences. This effect is explored to improve the dynamic identification scheme. Data are collected by wireless sensors specifically designed for railway catenary systems. The sensors can be mounted arbitrarily to satisfy a beneficial description of the motion. In this investigation, up to ten sensors are used to measure the response within one span. The structural behaviour is examined in the vertical and lateral directions by collecting a significant amount of passage data. These data are analysed for both directions, in terms of power spectra, peak histograms, and spectrograms. Individual passages are analysed, as well as all passages, at once. Two catenary sections are included to determine system similarities and differences and to evaluate the combined effort of the two directions, one old and one new, both situated in Norway.
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