Vibro-acoustic modelling of high-speed train composite floor and contribution analysis of its constituent materials

The floor is crucial for the interior noise control in a high-speed train. However, due to its large size (25 m × 2.87 m × 0.16 m) and complex structure (consists of multiple layers of different materials), there is no appropriate approach for floor modelling. The vibro-acoustic characteristics of the composite floor and the contributions of its constituent materials are yet to be studied. In this study, both in-situ measurements and simulation analyses were conducted to address this issue. First, the sound insulation of the floor was measured in a large semi-anechoic room using a real high-speed coach. Then, the floor vibration transmission of the same coach was measured on a high-speed line with the train running at speeds from 250 km/h to 350 km/h. Second, a systematic vibro-acoustic modelling method of the composite floor has been proposed. The modelling steps from the single structure or material to the whole floor are presented and discussed in detail. The complete model is validated by the experimental results. Finally, using the verified vibro-acoustic model of the composite floor, the contributions of its constituent materials are analysed. The results show that the spectral characteristics of the predicted results are consistent with those of experimental results, and their amplitude difference is small. The modelling method and the model are reasonable and reliable. Compared with sound insulation and absorption materials, the wooden keel has a more significant influence on the sound insulation and vibration transmission of the composite floor. Therefore, for noise and vibration control of the composite floor, the focus should be on the design of the wooden keel including the number, arrangement, and material.