Sensitivity Analysis of the Rectangular Trenches Employed in Suppression of the High-Speed Train-Induced Ground Vibrations

2010 ◽  
Author(s):  
Davood Younesian ◽  
Mehran Sadri
Keyword(s):  
High Speed ◽  
Vibration Reduction ◽  
Moving Loads ◽  
High Speed Train ◽  
Ground Vibrations ◽  
Infinite Domain ◽  
Aspect Ratios ◽  
Different Types ◽  
High Speed Trains ◽  
Train Speed

Ground vibrations generated by high-speed trains are studied in this paper. Open trenches are included in modeling and the problem is formulated using elasticity theory. The ground is modeled by a semi-infinite domain and the embankment with finite layers and the high-speed train is simulated by moving loads. The analytical solution is obtained in frequency domain and the peak particle velocity (PPT) is then achieved for different types of open trenches with different aspect ratios and distance from the track centerline. A parametric study is then carried out and effects of different parameters including the train speed and ground properties on vibration reduction factors are investigated.

Analysis of Dynamic Wind of Sound Barrier under High Speed Train

2013 ◽  
Vol 361-363 ◽  
pp. 1536-1542
Author(s):  
Zhou Shi ◽  
Jun Li Guo ◽  
Wei Feng Su ◽  
Shuang Yang Zhang
Keyword(s):  
High Speed ◽  
Measured Data ◽  
Air Pressure ◽  
Turbulent Model ◽  
High Speed Train ◽  
Sound Barrier ◽  
Barrier Region ◽  
High Speed Trains ◽  
Train Speed ◽  
Volume Method

The special dynamic pulsating air pressure acting on the surface of sound barrier can be aroused by passing high speed train, making sound barrier structure and components prone to destruction and other issues. Based 3-D unsteady k-ε two-equation turbulent model, dynamic processes of high-speed trains passing the sound barrier region at different speeds and many factors are simulated and analyzed by using moving mesh finite volume method. The results of dynamic numerical calculated pulsating air pressure results and the effecting rule of various parameters were obtained, and compared with the measured data. It is showed that the air pressure value increases with the increasing train speed and the dynamic numerical calculated pulsating air pressure curves shape and effecting rule of parameters are all well matched with the measured data, but the air pressure value is slightly larger. At last, based on the results of numerical calculation, the addition of static air pressure value caused by high speed train is put forward.

scholarly journals Three-Dimensional Dynamic Analyses of Track-Embankment-Ground System Subjected to High Speed Train Loads

2014 ◽  
Vol 2014 ◽  
pp. 1-19 ◽  
Author(s):  
Qiang Fu ◽  
Changjie Zheng
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Concrete Slab ◽  
Three Dimensional ◽  
Element Model ◽  
Moving Loads ◽  
Infinite Elements ◽  
Ground System ◽  
High Speed Trains ◽  
Train Speed

A three-dimensional finite element model was developed to investigate dynamic response of track-embankment-ground system subjected to moving loads caused by high speed trains. The track-embankment-ground systems such as the sleepers, the ballast, the embankment, and the ground are represented by 8-noded solid elements. The infinite elements are used to represent the infinite boundary condition to absorb vibration waves induced by the passing of train load at the boundary. The loads were applied on the rails directly to simulate the real moving loads of trains. The effects of train speed on dynamic response of the system are considered. The effect of material parameters, especially the modulus changes of ballast and embankment, is taken into account to demonstrate the effectiveness of strengthening the ballast, embankment, and ground for mitigating system vibration in detail. The numerical results show that the model is reliable for predicting the amplitude of vibrations produced in the track-embankment-ground system by high-speed trains. Stiffening of fill under the embankment can reduce the vibration level, on the other hand, it can be realized by installing a concrete slab under the embankment. The influence of axle load on the vibration of the system is obviously lower than that of train speed.

Comparative study on the use of acoustic emission and vibration analyses for the bearing fault diagnosis of high-speed trains

2021 ◽  
pp. 147592172110360
Author(s):  
Dongming Hou ◽  
Hongyuan Qi ◽  
Honglin Luo ◽  
Cuiping Wang ◽  
Jiangtian Yang
Keyword(s):  
Acoustic Emission ◽  
Fault Diagnosis ◽  
High Speed ◽  
High Speed Train ◽  
Signal Attenuation ◽  
Transmission Path ◽  
Bearing Fault Diagnosis ◽  
Operation Conditions ◽  
Fault Features ◽  
High Speed Trains

A wheel set bearing is an important supporting component of a high-speed train. Its quality and performance directly determine the overall safety of the train. Therefore, monitoring a wheel set bearing’s conditions for an early fault diagnosis is vital to ensure the safe operation of high-speed trains. However, the collected signals are often contaminated by environmental noise, transmission path, and signal attenuation because of the complexity of high-speed train systems and poor operation conditions, making it difficult to extract the early fault features of the wheel set bearing accurately. Vibration monitoring is most widely used for bearing fault diagnosis, with the acoustic emission (AE) technology emerging as a powerful tool. This article reports a comparison between vibration and AE technology in terms of their applicability for diagnosing naturally degraded wheel set bearings. In addition, a novel fault diagnosis method based on the optimized maximum second-order cyclostationarity blind deconvolution (CYCBD) and chirp Z-transform (CZT) is proposed to diagnose early composite fault defects in a wheel set bearing. The optimization CYCBD is adopted to enhance the fault-induced impact response and eliminate the interference of environmental noise, transmission path, and signal attenuation. CZT is used to improve the frequency resolution and match the fault features accurately under a limited data length condition. Moreover, the efficiency of the proposed method is verified by the simulated bearing signal and the real datasets. The results show that the proposed method is effective in the detection of wheel set bearing faults compared with the minimum entropy deconvolution (MED) and maximum correlated kurtosis deconvolution (MCKD) methods. This research is also the first to compare the effectiveness of applying AE and vibration technologies to diagnose a naturally degraded high-speed train bearing, particularly close to actual line operation conditions.

scholarly journals A Study on the Energy-Harvesting Device with a Magnetic Spring for Improved Durability in High-Speed Trains

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 830
Author(s):  
Jaehoon Kim
Keyword(s):  
Energy Harvesting ◽  
High Speed ◽  
Permanent Magnets ◽  
Critical Issue ◽  
Sensor Nodes ◽  
High Speed Train ◽  
Vibration Energy Harvesting ◽  
Magnetic Spring ◽  
High Speed Trains ◽  
Energy Harvesting Devices

Durability is a critical issue concerning energy-harvesting devices. Despite the energy-harvesting device’s excellent performance, moving components, such as the metal spring, can be damaged during operation. To solve the durability problem of the metal spring in a vibration-energy-harvesting (VEH) device, this study applied a non-contact magnetic spring to a VEH device using the repulsive force of permanent magnets. A laboratory experiment was conducted to determine the potential energy-harvesting power using the magnetic spring VEH device. In addition, the characteristics of the generated power were studied using the magnetic spring VEH device in a high-speed train traveling at 300 km/h. Through the high-speed train experiment, the power generated by both the metal spring VEH device and magnetic spring VEH device was measured, and the performance characteristics required for a power source for wireless sensor nodes in high-speed trains are discussed.

The Aerodynamic Characteristics of the Pantograph When the Train Passes Through the Tunnel

2017 ◽  
Author(s):  
Dilong Guo ◽  
Wen Liu ◽  
Junhao Song ◽  
Ye Zhang ◽  
Guowei Yang
Keyword(s):  
High Speed ◽  
Aerodynamic Force ◽  
Maximum Amplitude ◽  
Aerodynamic Characteristics ◽  
High Speed Train ◽  
Expansion Waves ◽  
Compression And Expansion ◽  
High Speed Trains ◽  
Current Characteristics ◽  
Pass Through

The aerodynamic force acting on the pantograph by the airflow is obviously unsteady and has a certain vibration frequency and amplitude, while the high-speed train passes through the tunnel. In addition to the unsteady behavior in the open-air operation, the compressive and expansion waves in the tunnel will be generated due to the influence of the blocking ratio. The propagation of the compression and expansion waves in the tunnel will affect the pantograph pressure distribution and cause the pantograph stress state to change significantly, which affects the current characteristics of the pantograph. In this paper, the aerodynamic force of the pantograph is studied with the method of the IDDES combined with overset grid technique when high speed train passes through the tunnel. The results show that the aerodynamic force of the pantograph is subjected to violent oscillations when the pantograph passes through the tunnel, especially at the entrance of the tunnel, the exit of the tunnel and the expansion wave passing through the pantograph. The changes of the pantograph aerodynamic force can reach a maximum amplitude of 106%. When high-speed trains pass through tunnels at different speeds, the aerodynamic coefficients of the pantographs are roughly the same.

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