Article
Engineering, Mechanical
Qing Wu, Yan Sun, Maksym Spiryagin, Colin Cole
Summary: This study developed a three-dimensional railway track model considering four structure layers, which effectively simulated track longitudinal forces and rail creep phenomenon.
VEHICLE SYSTEM DYNAMICS
(2021)
Article
Engineering, Multidisciplinary
Lei Xu, Hubing Liu, Zhiwu Yu
Summary: Modeling, evaluating, and predicting slab track damage and its evolution is currently a challenge and hot topic. This work presents finite element modeling methods and computer modules to compile a simulation program to evaluate slab track damage evolution. The necessity of considering combined fatigue and interfacial damages of slab tracks is illustrated.
APPLIED MATHEMATICAL MODELLING
(2022)
Article
Chemistry, Multidisciplinary
Cecilia Vale
Summary: This research used numerical methods to study the effects of wheel flats with different geometric configurations on the dynamic behavior of both ballasted and slab tracks. The results showed that the dynamic force was higher on the slab track, while the maximum vertical displacement was higher on the ballasted track.
APPLIED SCIENCES-BASEL
(2021)
Article
Mechanics
Zheng Li, Lei Xu, Xiangyun Deng
Summary: In this study, a simulation program is developed using finite element modeling and numerical iterative method to reveal the coordinated deformation process of slab track-soil interaction. The contact-separation relationship at the slab track-soil interface, the interlayered gap between slab track and soil surface, and additional track deformation are considered as additional geometric excitations of the VTS interaction system. Numerical studies clarify the deformation coordinated mechanism of slab track-soil interaction and its influence on vehicle-induced vibrations.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Engineering, Geological
Yu Guo, Qiang Sun, Yu Sun
Summary: This study establishes a theoretical model considering nonlinear subgrade support and track weight, evaluates the effects of differential subgrade settlement on the dynamic performance of high-speed trains and the infrastructure, and proposes control thresholds based on dynamic characteristics.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2023)
Article
Engineering, Civil
D. Tholken, J. E. Abdalla Filho, J. Pombo, J. Sainz-Aja, I Carrascal, J. Polanco, A. Esen, O. Laghrouche, P. Woodward
Summary: Accurate computational modeling of railway systems plays a crucial role in improving system efficiency and reliability. This study developed calibrated 3D Finite Element models for slab track systems based on full-scale dynamic tests, and identified key material properties through parametric analysis.
TRANSPORTATION GEOTECHNICS
(2021)
Article
Engineering, Geological
Qingzhi Ye, Qiang Luo, David P. Connolly, Tengfei Wang, Hongwei Xie, Haibo Ding
Summary: The aim of this study is to develop new knowledge about the dynamic behavior of concrete slab track systems enhanced with asphaltic underlays. A numerical simulation approach is used, which includes a coupled multi-body vehicle-track model and a 3D dynamic finite element track-ground model. The models are validated and used to simulate different thicknesses of asphaltic underlays, and the dynamic response is compared to analyze the stress, deflection, acceleration, and strain. The results indicate that stress concentrations occur near the concrete base joints, which should be considered in the design of asphaltic underlays.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2023)
Article
Construction & Building Technology
C. Charoenwong, D. P. Connolly, A. Colaco, P. Alves Costa, P. K. Woodward, A. Romero, P. Galvin
Summary: Concrete slab railway tracks have higher initial capital costs but lower operational costs compared to ballasted tracks. Ballasted tracks require more frequent maintenance, and therefore concrete slab tracks are commonly used on higher linespeed routes. However, the optimal speed ranges for the two track forms have not been extensively studied. This paper investigates the train-induced differential settlement of ballast and non-ballasted tracks on intercity and high-speed lines. The study shows that ballasted tracks experience higher train-induced settlement and more pronounced track geometry degradation at higher linespeeds.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Engineering, Civil
Ilaria Grossoni, William Powrie, Antonis Zervos, Yann Bezin, Louis Le Pen
Summary: The geometry of a ballasted railway deteriorates over time due to plastic settlement of the track-bed, which is difficult to predict accurately. Current empirical equations do not fully reflect the behavior of soil subgrades in cyclic loading, leading to the development of a semi-analytical approach to calculate plastic settlements more effectively. This new model is able to reproduce observed aspects of railway track settlement based on known behavior of soils and ballast in cyclic loading.
TRANSPORTATION GEOTECHNICS
(2021)
Article
Acoustics
Yu Sun, Mei Chen
Summary: Periodic slab tracks are widely used in high-speed railway and urban subway systems. This paper introduces a hybrid Green's function method to model the dynamics of the periodic slab track and analyzes the truncation errors caused by this method. The proposed model shows nearly the same computational accuracy as the finite element method but greatly improves efficiency, while also revealing the influence of longitudinal uneven stiffness on slab displacement and stress.
JOURNAL OF SOUND AND VIBRATION
(2021)
Article
Engineering, Civil
Emil Aggestam, Jens C. O. Nielsen, Karin Lundgren, Kamyab Zandi, Anders Ekberg
Summary: This paper focuses on optimizing the dimensions and concrete types of slab tracks in order to minimize greenhouse gas emissions, while meeting the static dimensioning analysis requirement of the European standard. Using a 3D model, the dynamic vehicle-track interaction is analyzed, and contact forces and stress fields are calculated. The study concludes that the panel thickness can be reduced without risking crack initiation, and also develops a reinforced concrete model to predict crack widths and assess when steel reinforcement can be reduced.
ENGINEERING STRUCTURES
(2022)
Article
Transportation Science & Technology
Qiang Zhang, Xuehui Zhang, Lei Xu
Summary: This research aims to optimize the auto-assembling process in the slab track-bridge coupling matrices formulation and improve computational efficiency by truncating dynamic matrices. The study successfully solves the problem of modeling slab track-bridge interaction subject to a moving train and presents numerical examples to demonstrate the applicability of the proposed methods.
INTERNATIONAL JOURNAL OF RAIL TRANSPORTATION
(2022)
Article
Engineering, Civil
Hamidreza Heydari-Noghabi, Jose Nuno Varandas, Jabbar Ali Zakeri, Morteza Esmaeili
Summary: This study investigates the use of a combined transition system consisting of an approach slab and additional rails to improve the geometrical and mechanical defects of railway lines. Experimental tests and numerical simulations show that this transition system achieves a smooth stiffness transition between slab track and ballasted track.
KSCE JOURNAL OF CIVIL ENGINEERING
(2023)
Article
Construction & Building Technology
Amin Khajehdezfuly, Davood Poorveis, Amir Mohammad Amiri
Summary: This research developed a numerical model and a MATLAB code to investigate the effects of rail-pad and interlayer stiffness on the flexibility and fatigue life of railway concrete slab track. The findings show that reducing rail-pad stiffness and increasing interlayer stiffness can simultaneously improve the flexibility and fatigue life.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Engineering, Multidisciplinary
Shunlong Li, Dedao Wang, Chao Lin, Senrong Wang
Summary: This study investigates the friction performance degradation of the sliding layer in the China Railway Track System (CRTS) II. It utilizes long-term monitoring data to analyze the statistical characteristics and degradation performance of the friction coefficients. The results provide guidance for future maintenance and replacement decision making.
STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL
(2023)
Article
Engineering, Mechanical
Ling-Kun Chen, Hong-Xi Qin, Li-Zhong Jiang, Lei Xu
Summary: This paper focuses on rapid elastoplastic analyses of light rail vehicle (LRV) benchmark viaduct system under different seismic scenarios using the dynamic substructuring method (DSM). A new framework of train-track system space dynamics is constructed by combining the energy-variational principle with the vehicle-bridge interaction (VBI) system. Results indicate that large vertical ground motions (VGMs) greatly impact the seismic response of the LRV running safety in the low-frequency band compared to non-pulse-like near-fault ground motions (NFGMs) and far-field ground motions (FFGMs), emphasizing the importance of distinguishing velocity pulses when selecting NFGMs for assessing the nonlinear dynamic response of the VBI system.
VEHICLE SYSTEM DYNAMICS
(2021)
Article
Engineering, Mechanical
Lei Xu, Bin Zhu, Mansur Barhama Abulfathi, Yichen Meng
Summary: The study introduces a probabilistic model of track irregularities to select representative track irregularity sets with smaller samples. By effectively combining vehicle-track dynamics method and random simulation methods, the wheel and rail contact stresses can be efficiently quantified from a statistical view.
VEHICLE SYSTEM DYNAMICS
(2021)
Article
Engineering, Mechanical
Lei Xu, Tao Lu
Summary: This study focuses on the influence of sleeper finite element types on system dynamic responses in the context of vehicle-track interaction. The model's effectiveness has been validated through both frequency- and time- domain analysis in the numerical study. Investigation has been conducted on the effects of sleeper finite element type, sleeper support stiffness, and damping coefficient on system responses.
VEHICLE SYSTEM DYNAMICS
(2021)
Article
Acoustics
Lei Xu, Zhiwu Yu
Summary: This paper models a multi-rigid-body system with two-stage suspension systems running on a slab track system, considering the elastoplasticity of the track slab. The two-step iterative algorithm developed to solve the dynamic equations of motion for vehicle-track interactions has been shown to accurately and efficiently calibrate the vehicle-track dynamic behavior, with the longitudinal unevenness of track support stiffness significantly impacting the plasticity of track slabs.
JOURNAL OF VIBRATION AND CONTROL
(2021)
Article
Engineering, Mechanical
Lei Xu, Zheng Li, Yongsheng Zhao, Zhiwu Yu, Kun Wang
Summary: In this paper, modelling methods are developed to explore the dynamics of the vehicle-track system and its substructures. A coupled model is constructed to characterize the vehicle-track interaction, and a multi-finite-element coupling method is presented to integrate multiple substructures. A multi-time-step solution method is proposed to achieve a hybrid solution. Numerical examples demonstrate the accuracy and practicality of the proposed model and methods.
VEHICLE SYSTEM DYNAMICS
(2022)
Article
Acoustics
Kun Wang, Zhihui Zhu, Lei Xu
Summary: This study is devoted to analyzing the transient probability density function solutions of a stochastic oscillator with even nonlinearities under external excitation of Gaussian white noise using the extended exponential polynomial closure method. The numerical analysis shows that this method is effective and efficient for solving the transient analysis of the system, as compared to the results obtained by Monte Carlo simulation method. Additionally, the numerical results indicate that the transient probability density function solutions of the system responses are not symmetric about their nonzero means due to the presence of even nonlinearities.
JOURNAL OF VIBRATION AND CONTROL
(2022)
Article
Engineering, Mechanical
Lei Xu, Xiangming Liu
Summary: This paper introduces a matrix coupled model for vehicle-track interaction analysis with a focus on the crossing panel. The model assumes elastic wheel-rail contact and demonstrates the determination of two-point contact during the transition of the wheel load in the crossing panel. Results show the model's capability in capturing the main features of wheel-rail interaction and analyze the impact of track irregularities on the interaction.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2021)
Article
Engineering, Mechanical
Lei Xu, Yongsheng Zhao, Zixu Zhu, Zheng Li, Hubing Liu, Zhiwu Yu
Summary: This work focuses on random vibration analysis of railway systems to disclose possible dynamic behaviors, proposing a strategy to obtain representative track irregularity PSD samples by introducing practical tools. By combining simulation methods of track irregularities and vehicle-track dynamic interaction, the dynamic performance of vehicle-track systems can be evaluated efficiently.
VEHICLE SYSTEM DYNAMICS
(2022)
Article
Transportation Science & Technology
Zheng Li, Lei Xu, Dongli Wang, Zengjian Niu, Yongsheng Zhao, Wei Liu, Xinsheng Zhan
Summary: In this study, 2D and 3D vehicle-track-soil models are developed in a coupled manner. The IE method is introduced to simulate the soil far-field region, and case studies demonstrate the advantages of this model in improving computational efficiency and revealing the influence of vehicle speed on system dynamic performance.
INTERNATIONAL JOURNAL OF RAIL TRANSPORTATION
(2023)
Article
Engineering, Civil
Zheng Li, Lei Xu, Weidong Wang
Summary: This work proposes an engineering practical method to characterize the mapping relationship between soil deformation and system performance. The method incorporates static and dynamic analysis and utilizes wavelet transform for signal observation. It also discusses the influence of soil deformation on dynamic mapping from both time and frequency domains.
ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING
(2022)
Article
Mechanics
Hubing Liu, Zheng Li, Lei Xu
Summary: This study establishes a vehicle-track-subgrade interaction model to predict the cumulative settlement and its evolution characteristics of high-speed railway soft soil subgrade. The direct probability integral method is introduced for uncertainty quantification and reliability assessment. Numerical examples demonstrate the sensitivity and reliability assessment of cumulative settlement under different conditions.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Mechanics
Zheng Li, Lei Xu, Xiangyun Deng
Summary: In this study, a simulation program is developed using finite element modeling and numerical iterative method to reveal the coordinated deformation process of slab track-soil interaction. The contact-separation relationship at the slab track-soil interface, the interlayered gap between slab track and soil surface, and additional track deformation are considered as additional geometric excitations of the VTS interaction system. Numerical studies clarify the deformation coordinated mechanism of slab track-soil interaction and its influence on vehicle-induced vibrations.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Engineering, Civil
Zheng Li, Lei Xu, Pengfei Liu, Weidong Wang, Zhiping Zeng
Summary: In this paper, a subgrade model with nonlinear stiffness is integrated into a 3-D vehicle-track-subgrade (VTS) dynamic model. It accurately predicts the vehicle-induced railroad vibrations and reveals the nonlinear behavior of the subgrade soil.
TRANSPORTATION GEOTECHNICS
(2023)
