Session: 02-01-02: Product and Process Design 2

Paper Number: 164495

Robust Design of Train Anti-Climb Energy Absorber Under Complex Uncertain Boundary Conditions 

Train collision accidents are complex and diverse, with boundary conditions such as collision speed, offset range, and collision angle being highly uncertain. Existing thin-walled honeycomb anti-climbing energy absorbers are prone to bending under offset and angular conditions, leading to a significant reduction in energy absorption capacity, accompanied by risks of climbing and derailment. To address these issues, this paper proposes a robust design method for anti-climbing energy absorbers under complex and uncertain boundary conditions. Firstly, the causes of the complex and uncertain boundary conditions in train collisions are analyzed and categorized into macroscopic and transient factors. At the macroscopic level, differences in collision vehicle types result in variations in energy absorber types and installation positions. Additionally, on curved tracks, even identical vehicles cannot achieve perfectly concentric collisions. In transient conditions, even identical vehicle models on straight tracks rarely experience perfectly concentric collisions due to factors such as flexible connections between the vehicle body and bogie, vehicle snaking motion caused by conical treads, wheel wear, vehicle vibrations, and track irregularities. Based on this, five parameters—collision speed, vertical offset, lateral offset, vertical angle, and lateral angle—are used to characterize the boundary conditions of train collisions. These parameters are critical for understanding the variability in collision scenarios and ensuring the robustness of energy absorber designs. Subsequently, inspired by biomimicry, a robust shell structure for energy absorbers is proposed. The design draws inspiration from natural structures that exhibit high energy absorption capabilities under complex loading conditions. To complement the shell structure, negative Poisson's ratio metamaterials with specified mechanical properties are generated through topology optimization. The combination of the biomimetic shell and negative Poisson's ratio metamaterials forms the robust anti-climbing energy absorber, which is designed to maintain stable deformation modes and consistent energy absorption performance across a wide range of collision scenarios. Prototype samples of the proposed energy absorber are fabricated using selective laser melting technology. Experimental testing confirms that the biomimetic shell and negative Poisson's ratio metamaterials exhibit excellent energy absorption properties, with stable and predictable deformation modes under various loading conditions. The results demonstrate that the proposed design significantly outperforms traditional thin-walled honeycomb energy absorbers in terms of energy absorption capacity and resistance to bending under offset and angular collisions. Finally, a comprehensive comparison is conducted between the proposed robust anti-climbing energy absorber and traditional thin-walled honeycomb energy absorbers. Considering the complex and uncertain boundary conditions of train collisions, multiple scenarios are designed, including concentric collisions, large-range offsets, and angular collisions. The proposed energy absorber demonstrates consistently higher specific energy absorption across all scenarios, with significantly lower energy absorption degradation rates under offset and angular collision conditions compared to traditional structures. Experimental results confirm that the robust design effectively mitigates the risks of climbing and derailment, ensuring enhanced safety performance under diverse collision scenarios. This study provides a novel approach to improving the reliability and adaptability of anti-climbing energy absorbers in real-world train collision scenarios. By integrating biomimicry-inspired design principles with advanced materials and manufacturing techniques, the proposed method addresses the limitations of conventional energy absorbers and offers a promising solution for enhancing train safety under complex and uncertain collision conditions. The findings of this research contribute to the development of more robust and reliable energy absorption systems for railway vehicles, ultimately reducing the risks of accidents and improving passenger safety.

Presenting Author: Kun He Tongji University

Presenting Author Biography: He Kun, male, born in October 1999, is currently a Ph.D. candidate at the School of Transportation, Tongji University, where his research interests encompass rail vehicle passive safety and vehicle system dynamics.

Authors:

Kun He Tongji University
Hechao Zhou Tongji University
Jimin Zhang Tongji University