Decomposition method to determine acoustic indexes of components in low-noise design procedure of high-speed trains

A method for determining the acoustic indexes of the components based on vehicle noise simulation analysis was proposed. The acoustic indexes of the high-speed train components were divided into noise source and sound transfer path indexes according to the types. The prediction models of high-speed train exterior and interior noise were established respectively by using ray acoustics and statistical energy analysis methods. A set of initial parameters were selected as the model inputs to predict the exterior and interior noise, and the predicted results were compared with the top-level design targets of the vehicle. Based on the noise source, sound transfer path contribution, parameter sensitivity, and multi-objective optimization, the acoustic indexes of the noise source components and sound transfer path components were determined. Analysis results show that according to the exterior noise simulation analysis, the inputs of the noise source parameters can be regarded as a set of determination results of noise source indexes when the predicted exterior noise meets the top-level acoustic design targets and the design margin is within the acceptable range. In determining the sound transfer path indexes based on the interior noise simulation analysis, the inputs of the sound transfer path parameters can be regarded as a set of determination results of sound transfer path indexes when the predicted interior noise meets the top-level acoustic design targets and the design margin is within the acceptable range. However, when the noise source indexes or sound transfer path indexes do not satisfy the vehicle noise requirements, it is necessary to analyze the noise source or sound transfer path contribution, calculate the parameter sensitivity of the main contributing noise source or sound transfer path, and make the main contributing noise source or sound transfer path achieve the top-level acoustic design targets through correction iteration. Low-noise design procedure needs to integrate the feedback of multiple indicators continuously. The acoustic indexes of the components should be adjusted reasonably to ensure that the acoustic indexes of the components not only satisfy the top-level acoustic design targets but also show feasibility. © 2021, Editorial Department of Journal of Traffic and Transportation Engineering. All right reserved.