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A 3D rigid-flexible human-seat-vehicle-track coupling model is proposed to analyze high-speed train ride comfort. The seated human model is built based on the multi-body dynamic method. The human multi-axis excitation measurement data determines the model parameters. The detailed FE (finite element) car body model is built, and the model is calibrated by laboratory modal tests. The dynamic behavior of the high-speed train, running on both straight and curved tracks, is analyzed by using the rigid-flexible human-seat-vehicle-track coupling model. Then, the effect of the seat support parameters on the ride comfort of the high-speed train is analyzed, when the train travels on curved tracks. The results show that using the rigid car body model can overestimate the ride comfort of the high-speed train. The lateral and rolling motion of the car body, induced by curves can worsen the lateral dynamic performance of the passenger seats. At the different seat positions and for the different configurations of seats (three-abreast and two-abreast), selecting proper stiffness of the seat-floor and seat-sidewall supports can achieve comfort for the passengers. [ABSTRACT FROM AUTHOR]

The vibration of high-speed trains induced by track irregularities is a main factor affecting ride comfort. Especially, the long-wavelength track irregularities can reduce the passengers' ride comfort by increasing the vibration of the high-speed trains. A three-dimensional human body model coupled to a vehicle body and tracks is established to form a coupled human-seat-vehicle-track system for investigating the influence of the long-wavelength track irregularities on ride comfort. The parameters of the seated human model are determined by measurement based on the multi-island GA method. The coupled model is then used to evaluate the ride comfort of high-speed trains using ISO 2631 under the excitation of the track longitudinal level irregularities. The effects of primary, secondary suspension, and seat support vertical stiffness and damping on ride comfort are analysed. The results show that the track's longitudinal irregularities lead to high human body vibration levels and large ride comfort indices (lower ride comfort), especially when the irregularity excitation frequency is near the natural frequency of the high-speed train. The passengers' ride comfort is more sensitive to the vertical secondary suspension stiffness than the other suspension parameters. [ABSTRACT FROM AUTHOR]

The body of a high-speed train is a composite structure composed of different materials and structures. This makes the design of a noise-reduction scheme for a car body very complex. Therefore, it is important to clarify the key factors influencing sound insulation in the composite structure of a car body. This study uses machine learning to evaluate the key factors influencing the sound insulation performance of the composite floor of a high-speed train. First, a comprehensive feature database is constructed using sound insulation test results from a large number of samples obtained from laboratory acoustic measurements. Subsequently, a machine learning model for predicting the sound insulation of a composite floor is developed based on the random forest method. The model is used to analyze the sound insulation contributions of different materials and structures to the composite floor. Finally, the key factors influencing the sound insulation performance of composite floors are identified. The results indicate that, when all material characteristics are considered, the sound insulation and surface density of the aluminum profiles and the sound insulation of the interior panels are the three most important factors affecting the sound insulation of the composite floor. Their contributions are 8.5%, 7.3%, and 6.9%, respectively. If only the influence of the core material is considered, the sound insulation contribution of layer 1 exceeds 15% in most frequency bands, particularly at 250 and 500 Hz. The damping slurry contributed to 20% of the total sound insulation above 1000 Hz. The results of this study can provide a reference for the acoustic design of composite structures. [ABSTRACT FROM AUTHOR]