Interaction Dynamic Response of a High-Speed Train Moving Over Curved Bridges with Deficient or Surplus Superelevation

2021 ◽  
pp. 2150103
Author(s):  
Jin Shi ◽  
Dengke Ma ◽  
Ya Gao
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Three Dimensional ◽  
Reduction Rate ◽  
Numerical Algorithms ◽  
Vertical Displacement ◽  
Curved Bridges ◽  
Wheel Load ◽  
Circular Curves ◽  
Curve Radius

This paper proposes a three-dimensional dynamic model for high-speed railway trains moving over curved bridges considering the transition curves, circular curves, and superelevation. Key features of this study are to consider the nonlinear geometrical relationships and creep relationships between the wheels and rail, for which the interactive iterative numerical algorithms are developed based on the equations of vertical displacement and rolling of wheelset, and the torsional resonance conditions of the vehicle–bridge system are verified. The results show that the torsional vibration will cause amplification on vertical dynamic response of the beam on the outside edge of the curve. The deficient/surplus superelevation plays an important role in the lateral and torsional angular displacements of the bridge, and the peak of the torsional resonance response can be reduced by adjusting the practical superelevation of the curve. The variations of wheel–load reduction rate and derailment coefficient in the curve section are positively correlated to the deficient/surplus superelevation. The curve radius is the key factor affecting the wear and fatigue of wheel–rail, and when the curve radius is greater than 7000 m, the wear and fatigue can be significantly reduced. Running at a deficient superelevation level can also reduce the wear and fatigue.

scholarly journals Aerodynamic Response and Running Posture Analysis When the Train Passes a Crosswind Region on a Bridge

2021 ◽  
Vol 11 (9) ◽  
pp. 4126
Author(s):  
Jian Yan ◽  
Tefang Chen ◽  
E Deng ◽  
Weichao Yang ◽  
Shu Cheng ◽  
...  
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Reduction Rate ◽  
Navier Stokes ◽  
Aerodynamic Load ◽  
High Wind ◽  
Wheel Load ◽  
Posture Analysis ◽  
Safety Risks ◽  
Wind Barrier

Trains running on a bridge face more significant safety risks. Based on the Unsteady Reynolds-Averaged Navier–Stokes turbulence model, a three-dimensional Computational Fluid Dynamics computational model of the train–bridge–wind barrier was proposed in this study to measure the transient aerodynamic load of the train. The transient aerodynamic load was input into the wind–train–bridge coupling dynamic system to perform dynamic analysis of running safety. Significant fluctuations in the aerodynamic coefficients were found when the train entered and exited the wind barrier due to the dramatic change in flow pattern. The maximum value of the derailment coefficient decreased with the height of wind barriers, which hardly affected the wheel load reduction rate. The 2 m high wind barrier had no evident influence on the running posture of a general high-speed train, while the 4 m high wind barrier was proven to have better protection. Over-protection was found with an even higher wind barrier.

Numerical Study on the Running Safety of High-Speed Train under the Cross Wind

2014 ◽  
Vol 694 ◽  
pp. 109-113
Author(s):  
Xiang Dong Chen ◽  
Yu Gong Xu
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Three Dimensional ◽  
Reduction Rate ◽  
Aerodynamic Characteristics ◽  
High Speed Train ◽  
Wheel Load ◽  
The Cross ◽  
Set Up ◽  
Train Safety

With the increasing speed, the crosswind effect is the more and more obvious. The three dimensional aerodynamic model of the high-speed train was set up to study the aerodynamic characteristics of the train under the cross wind. Based on the vehicle system dynamics, the couple model for dynamics of wind-train-rail systems was set up to study the train safety under the wind load. The derailment coefficient and reduction rate of wheel load were analyzed under the different train speed, different wind velocity. The results of this research can provide a theoretical basis for the high-speed train safety.

Three-dimensional analyses of two high-speed trains crossing on a bridge

2003 ◽  
Vol 217 (2) ◽  
pp. 99-110
Author(s):  
H-T Lin ◽  
S-H Ju
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
High Speed ◽  
Three Dimensional ◽  
Dynamic Effect ◽  
Response Ratio ◽  
Element Analysis ◽  
Dynamic Finite Element Analysis ◽  
High Speed Trains ◽  
The One

This paper investigates the dynamic characteristics of the three-dimensional vehicle-bridge system when two high-speed trains are crossing on a bridge. Multispan bridges with slender piers and simply supported beams were used in the dynamic finite element analysis. A response ratio (RR) was defined in this study to represent the ratio of the vehicle-bridge interaction of two-way trains to that of a one-way train. The finite element results indicate that this ratio increases significantly when two-way trains run near the same speed, and the maximum value is approximately equal to or smaller than two for the vertical dynamic response. This means that the maximum dynamic response of the two-way trains is at most twice that of the one-way train. When the two-way train speeds are sufficiently different, the response ratio approaches one on average, which means that the dynamic effect of the two-way train is similar to that of the one-way train. Finite element results also indicate that the averaged response ratio in the three global directions is about 1.65 when the two-way trains run at the same speed.

Measuring the angle of attack of beating insect wings: robust three-dimensional reconstruction from two-dimensional images

1997 ◽  
Vol 200 (21) ◽  
pp. 2693-2704 ◽  
Author(s):  
A Willmott ◽  
C Ellington
Keyword(s):  
High Speed ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Numerical Algorithms ◽  
Longitudinal Axis ◽  
Wing Motion ◽  
Insect Wings ◽  
High Speed Film ◽  
Dimensional Reconstruction ◽  
Left And Right

A robust technique for determining the angle of attack of insect wings from film of free flight has to date proved elusive. This report describes the development of two new methods ­ the Strips and Planes techniques ­ which were designed to overcome some of the limitations experienced in previous studies. The accuracy and robustness of these novel methods were tested extensively using simulated hawkmoth wing outlines generated for a realistic range of wing positions and torsion. The results were compared with those from two existing methods ­ the Symmetry and Landmarks procedures. The performance of the latter technique will be strongly species-dependent; it could not be successfully applied to hawkmoth flight because of practical difficulties in obtaining suitable landmarks. The Planes method was the least successful of the remaining techniques, especially during those phases of the wingbeat when the orientations of the two wings relative to the camera viewpoint were similar. The Symmetry and Strips methods were tested further to investigate the effects on their performance of introducing additional camber or wing motion asymmetry. The results showed clearly that the Strips method should be the technique of choice wherever the axis of wing torsion is close to the longitudinal axis of the wing. The procedure involves the experimenter matching a model wing divided into chordwise strips to the true wing outline digitized from high-speed film. The use of strips rather than the points digitized in previous studies meant that the analysis required only one wing outline to be digitized. Symmetry of motion between the left and right wings is not assumed. The implications of requiring human input to the Strips method, as opposed to the strictly numerical algorithms of the alternative techniques, are discussed. It is argued that the added flexibility that this provides in dealing with images which have typically been recorded in suboptimal conditions outweighs the introduction of an element of subjectivity. Additional observations arising from the use of the Strips analysis with high-speed video sequences of hawkmoth flight are given.

Three-Dimensional Dynamic Response Analysis of Shield Tunnel under Train Loads

2011 ◽  
Vol 90-93 ◽  
pp. 2062-2067 ◽  
Author(s):  
Zhan Rui Wu ◽  
Tai Yue Qi ◽  
Lin Zhong
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Three Dimensional ◽  
Shield Tunnel ◽  
Response Analysis ◽  
High Speed Train ◽  
Lining Structure ◽  
Design Speed

The vibration loads will be produced between wheel and rail on the running of the high-speed Train. The vibration energy will be transferred to the ground formation through the rail, guiding bed and tunnel lining structure, thereby causing vibration between the formation and surface and environmental interference effect problems. Thus the research of related issues caused by the high-speed train vibration has the vital great significance. The train design speed of the Shiziyang shield tunnel for Guangzhou-Shenzhen-Hong Kong passenger dedicated line is up to 350km/h. In this paper the research object is located in the segment of the homogeneous formation of the Shiziyang shield tunnel. The analysis of this paper includes the dynamic response rules of the shield tunnel and formation under the single high-speed train loads and the law of the pore water pressure accumulation and dispersion under train cyclic loading.

scholarly journals Modeling the Dynamic Behavior of Track Transitions Along Shared Track Corridors

2021 ◽  
Vol 7 ◽  
Author(s):  
Wenjing Li ◽  
Wenting Hou ◽  
Debakanta Mishra ◽  
Erol Tutumluer
Keyword(s):  
Dynamic Response ◽  
Dynamic Behavior ◽  
High Speed ◽  
Reaction Force ◽  
Vertical Displacement ◽  
Passenger Train ◽  
Bridge Model ◽  
Freight Car ◽  
The Difference ◽  
Train Loading

This paper presents findings from an analytical modeling effort undertaken to study the dynamic response of track transitions along shared-track corridors. A recently developed train-track-bridge model was used for this purpose. First, the model predictions are verified using field instrumentation data as well as data from other published literatures. Subsequently, the model is used to analyze the dynamic response of a typical bridge approach under the passage of a high-speed passenger train as well as six different freight trains comprising different freight car types. A speed sensitivity analysis of a freight train comprising one specific freight car type is also carried out. Geometric configuration of different freight trains is assessed as well as weight and speed of operation. Different track response parameters, including vertical displacement and rail-tie reaction force, are considered to highlight the differences in the track dynamic behavior under freight and passenger train loading. Analyses in both time and frequency domains illustrate the difference in track behavior under freight and passenger train loading. The significance of gap development at the tie-ballast interface near track transitions has been emphasized by illustrating the effect of tie gap on the dynamic track behavior. The paper concludes by emphasizing the importance of special consideration to track dynamic behavior for shared-track corridors.

Dynamic response of high speed vehicles and sustaining curved bridges under conditions of resonance

2016 ◽  
Vol 114 ◽  
pp. 61-74 ◽  
Author(s):  
Qing Zeng ◽  
Y.B. Yang ◽  
Elias G. Dimitrakopoulos
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Curved Bridges

scholarly journals Sudden Variation Effect of Aerodynamic Loads and Safety Analysis of Running Trains When Entering Tunnel Under Crosswind

2020 ◽  
Vol 10 (4) ◽  
pp. 1445 ◽  
Author(s):  
Weichao Yang ◽  
E Deng ◽  
Zhihui Zhu ◽  
Mingfeng Lei ◽  
Chenghua Shi ◽  
...  
Keyword(s):  
High Speed ◽  
Coupling Effect ◽  
Reduction Rate ◽  
Interaction Model ◽  
Train Track ◽  
Wheel Load ◽  
Safety Risk ◽  
Aerodynamic Loads ◽  
Track System ◽  
High Speed Trains

Sudden variation of aerodynamic loads is a potential source of safety accidents of high-speed trains (HSTs). As a follow-up investigation on the aerodynamic response of a HST that enters a tunnel under crosswind environment, this paper focuses on the transient response of a HST’s safety indices based on the train–track coupling interaction model. Firstly, a wind–train–track coupling dynamic model is proposed by introducing transient aerodynamic loads into the vehicle–track system. Secondly, the temporal evolution of safety coefficients indicates that the train’s safety risk increases during tunnel entry with crosswind. Results show that the derailment coefficients and wheel load reduction rate during tunnel entry are not only larger than those in open air, but also those inside the tunnel are due to the sudden disappearance of wind excitation at the tunnel entrance. In addition, the characteristic wind curve, which is the wind velocity against the train speed, is presented for application based on the current specification of the safety criteria threshold. The investigation will be useful in assessing the safety risk of a running train subjected to other aerodynamic attacks, such as the coupling effect of an infrastructure scenario and crosswind in a windy area.

scholarly journals Experimental and Numerical Study of the Dynamic Response of XCC Pile–Raft Foundation under High-Speed Train Loads

2021 ◽  
Vol 11 (19) ◽  
pp. 9260
Author(s):  
Qiang Fu ◽  
Jie Yuan
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Large Scale ◽  
Numerical Study ◽  
Soft Soil ◽  
Composite Foundation ◽  
Scale Model ◽  
Vibration Velocity ◽  
Wheel Load ◽  
Foundation Soil

A series of dynamic large-scale model tests and three-dimensional finite element analyses were conducted to investigate the dynamic response of track embankment and XCC pile-raft composite foundation in soft soil for a ballastless high-speed railway under moving train loads. The results indicate that the vibration velocity obtained from the FE numerical simulation agrees well with that from the model test in vibration waveform, amplitude, and frequency characteristics. The peak values corresponding to the passing frequency of train carriage geometry (lc = 25 m), bogie (lab = 7.5 m), and axle distance (lwb = 2.5 m) respectively reflect the characteristic frequencies of the train compartment, adjacent bogie, and wheel load passing through. The peak velocity significantly depends on the distance from the track center in the horizontal direction, of which the attenuation follows the exponential curve distribution. The vibration velocities decrease rapidly within embankment, show a vibration enhancement region from raft to the 1 m depth of foundation soil, then decreases gradually along the subsoil foundation, to a very low level at the bottom of the subsoil, which is much lower than that at the track slab and roadbed. The pile-raft composite foundation can reduce the vibration level effectively and improve the safety of trains running in soft soil areas.

scholarly journals Dynamic Response of Orthogonal Three-Dimensional Woven Carbon Composite Beams Under Soft Impact

2015 ◽  
Vol 82 (12) ◽  
Author(s):  
P. Turner ◽  
T. Liu ◽  
X. Zeng
Keyword(s):  
Finite Element ◽  
Composite Materials ◽  
Dynamic Response ◽  
Finite Element Modeling ◽  
High Speed ◽  
Three Dimensional ◽  
Composite Beams ◽  
High Speed Photography ◽  
Element Modeling ◽  
Back Face

This paper presents an experimental and numerical investigation into the dynamic response of three-dimensional (3D) orthogonal woven carbon composites undergoing soft impact. Composite beams of two different fiber architectures, varying only by the density of through-thickness reinforcement, were centrally impacted by metallic foam projectiles. Using high-speed photography, the center-point back-face deflection was measured as a function of projectile impulse. Qualitative comparisons are made with a similar unidirectional (UD) laminate material. No visible delamination occurred in orthogonal 3D woven samples, and beam failure was caused by tensile fiber fracture at the gripped ends. This contrasts with UD carbon-fiber laminates, which exhibit a combination of widespread delamination and tensile fracture. Post impact clamped–clamped beam bending tests were undertaken across the range of impact velocities tested to investigate any internal damage within the material. Increasing impact velocity caused a reduction of beam stiffness: this phenomenon was more pronounced in composites with a higher density of through-thickness reinforcement. A three-dimensional finite-element modeling strategy is presented and validated, showing excellent agreement with the experiment in terms of back-face deflection and damage mechanisms. The numerical analyses confirm negligible influence from through-thickness reinforcement in regard to back-face deflection, but show significant reductions in delamination damage propagation. Finite-element modeling was used to demonstrate the significant structural enhancements provided by the through-the-thickness (TTT) weave. The contributions to the field made by this research include the characterization of 3D woven composite materials under high-speed soft impact, and the demonstration of how established finite-element modeling methodologies can be applied to the simulation of orthogonal woven textile composite materials undergoing soft-impact loading.

Sign in / Sign up

Export Citation Format

Share Document