Discrete wavenumber analysis methods with application to panel structures and slab railway tracks

Modern railway vehicles are built using aluminium extruded panels. The acoustic performance of these controls the interior environment of the vehicles. However, there is currently no satisfactory method of analysis of the acoustic performance that would aid their design. Railways are also adopting novel track designs constructed as continuous concrete slab, in order to reduce maintenance costs and improve reliability. This proposal is based on the idea that extruded panels, the new track designs and a number of other applications in the railway industry and beyond would be analysed efficiently and in design detail using the same numerical method, namely a coupled Finite Element/Boundary Element 'two-and-a-halfdimensional' analysis.This method has already been developed for modelling the propagation of vibrations in the ground. It is appropriate to use this method where full three-dimensional analyses would require too great a computing resource and the structure has a constant geometry in two dimensions. It is intended to extend the existing method with suitable finite elements for plates and shells and with acoustic boundary element domains coupled to the structure. By this means detailed vibro-acoustic analysis will be possible for the structures of interest. The development of the method will include versions for finite-length structures and for infinite structures.For the extruded panels the method will also be applied to develop an SEA-based model for extruded panels, appropriate for use in the early stages of rolling stock design. For the track the detailed vibration and noise radiation analysis that the model will allow, have become increasingly important aspects of design.