Key Takeaways & Executive Findings
- •• A novel 3D human-seat-vehicle-track coupling model was developed to accurately assess high-speed train ride comfort, incorporating multi-axis human body dynamics. • Floor acceleration alone underestimates passenger discomfort; seat and backrest connection points exhibit higher vibration amplitudes in human-sensitive frequency ranges. • Track geometric irregularities and train meeting conditions significantly degrade ride comfort, especially when excitation frequencies approach the natural frequency of the human-seat-vehicle system. • Transient aerodynamic forces during train meetings induce car body roll and lateral motion at 2 Hz, further reducing passenger comfort.
Abstract
Typically, seat or floor acceleration is used to evaluate the ride comfort of a high-speed train. However, the dynamic performance of the human body significantly differs from that of the floor. Therefore, using the car body floor and seat accelerations to calculate the ride comfort index of a high-speed train may not reflect the true feelings of passengers. In this study, a 3D human-seat-vehicle-track coupling model was established to investigate the ride comfort of high-speed train passengers. The seated human model, which considers the longitudinal, lateral, vertical, pitching, yawing, and rolling motions, comprises the head, upper torso, lower torso, pelvis, thighs, and shanks. The model parameters were determined using multi-axis excitation measurement data based on a genetic algorithm. Subsequently, the applicability of the small-angle assumption and natural modes of the human model is analyzed. Using the coupling system model, the vibration characteristics of the human-seat interaction surface were analyzed. The ride comfort of the high-speed train and human body dynamic performance were analyzed under normal conditions, track geometric irregularities and train meeting conditions. The results showed that the passenger seats in the front and rear rows adjacent to the window had a higher acceleration value than the others. The human backrest and seat pad connection points have higher vibration amplitudes than the car body floor in the human-sensitive frequency range, indicating that using the acceleration values on the floor may underestimate the discomfort of passengers. The ride comfort of high-speed trains diminishes in the presence of track geometric irregularities and when trains pass each other. When the excitation frequency of track geometry irregularities approached the natural frequency of the human-seat-vehicle system, ride comfort in high-speed trains decreased significantly. Moreover, using seat acceleration to evaluate passenger ride comfort overlooks the vibration characteristics of the human body. The transient aerodynamic force generated when the train meets can cause a larger car body roll and lateral motion at 2 Hz, which, in turn, decreases the passenger ride comfort. This study presents a detailed human-seat-vehicle-track coupling system that can reflect a passenger’s dynamic performance under complex operating conditions.
1. Introduction
The ride comfort of passengers in high-speed trains is a key issue for railway engineers. Although the vertical vibration of high-speed trains is the leading cause of poor ride comfort, lateral and longitudinal vibrations can also aggravate ride comfort when the train operating environment is poor (bad wheel-rail profile, transverse wind load, track irregularity, passing turnout, etc.) [1, 2]. In addition, when the human body is under a multi-axis vibration stimulus, its dynamic performance is significantly different from that under single-axis vibration excitation. Therefore, it is necessary to propose a more reasonable and accurate model of the human-vehicle-track coupling state to evaluate the ride comfort of passengers on high-speed trains and guide existing vibration reduction measures [3, 4].
Researchers have proposed several human-vehicle-track coupling dynamic models to analyze the dynamic performance of a seated human on a train. The seated human was modeled using the lumped-parameter model, which is simple but has high computational efficiency. Based on human anatomy, the human body is divided into different parts; each body segment is considered a concentrated mass, and the interconnection between each part is modeled by linear springs and dampers [5–7]. This model is widely used to estimate high-speed train ride comfort and analyze seated human dynamic performance. A seat-human coupling mode with 11 degrees of freedom (DOF) was established by Zhang et al. [8], and the longitudinal, lateral, and vertical dynamic performances of the head and organs were analyzed.
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Hanwen Xu, Xinbiao Xiao, Xiaoqing Dong, Jian Han, Peng Chen, Qin Hu, Xuesong Jin (2025). Dynamic Modeling of the Three-Dimensional Seated Human Body for High-Speed Train Ride Comfort Analysis. Chinese Journal of Mechanical Engineering. https://doi.org/10.1186/s10033-025-01205-x
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Frequently Asked Questions
What is the main contribution of this paper?
The paper develops a detailed 3D human-seat-vehicle-track coupling model that incorporates multi-axis human body dynamics, providing a more accurate assessment of high-speed train ride comfort compared to traditional floor or seat acceleration measurements.
How does the proposed model improve ride comfort evaluation?
By considering the dynamic response of the human body, the model reveals that floor acceleration underestimates passenger discomfort, especially in the human-sensitive frequency range, and captures the effects of track irregularities and train meeting conditions on comfort.
What are the key findings regarding track irregularities and train meetings?
Track geometric irregularities and train meeting conditions significantly degrade ride comfort. When excitation frequencies approach the natural frequency of the human-seat-vehicle system, comfort decreases markedly. Train meetings cause car body roll and lateral motion at 2 Hz, further reducing comfort.
How were the human model parameters determined?
The parameters were identified using multi-axis excitation measurement data and a genetic algorithm, ensuring the model accurately represents the dynamic behavior of a seated human.
What practical implications does this research have for high-speed train design?
The findings suggest that ride comfort evaluations should incorporate human body dynamics, and vibration reduction measures should target the human-sensitive frequency range, particularly at seat and backrest connection points, to improve passenger comfort.
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