scholarly journals Structural Improvement of the ω-Type High-Speed Rail Clip Based on a Study of Its Failure Mechanism

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Xiaogang Gao ◽  
Anbin Wang ◽  
Yu He ◽  
Xiaohan Gu
Keyword(s):  
Failure Mechanism ◽  
Fatigue Test ◽  
High Frequency ◽  
High Speed ◽  
Excitation Frequency ◽  
Test System ◽  
Vibration Measurement ◽  
High Speed Rail ◽  
Resonant Frequencies ◽  
Rail Wear

In the circumstances of high-speed railways, the wheel-rail vibration is significantly aggravated by polygonal wheel wear and rail corrugation, which subsequently leads to the wheel-rail interaction at higher frequencies and potential failure of the rail fastening. In this paper, a ω-type clip of the fastening in the CRH high-speed rail was used to investigate the failure mechanism. First, a dynamic wheel-rail coupling model and a finite element analysis of the rail clip were developed, from which the rail vibration frequency and modal frequencies of the clip with different installation torques were obtained. The experimental tests and modal simulation results were mutually verified. In addition, the real-time vibration measurement and the wheel-rail wear monitoring were carried out at a CRH high-speed railway site. It was found that the resonant frequencies of the ω-type clip in the installation condition coincided with the excitation frequencies of the wheel-rail interaction induced by wheel-rail wear. The high-frequency dynamic failure mechanism of a typical ω-type clip, W300-1, is put forward for the first time. Moreover, a high-frequency rail clip fatigue test system was designed and developed specifically for this study. The loading excitation frequency of the clip test used was set as 590 Hz, and the loading amplitude was 0.05 mm. After 125-minute operation of the test system, the clip was broken at the expected location predicted by the FEA model. The high-frequency fatigue test result further verified that the failure mechanism of the ω-type clip was due to the resonance of the clip with its excitation force from the wheel-rail interaction. Finally, the clip was then structurally improved taking into account the stiffness and mass, which led to its resonant frequencies shifting away from the high-frequency excitation range, hence avoiding resonance failure of the subject clip.

Experiment Analysis about Mechanical Properties of Rubber Bushing for Suspension Telescopic Shock Absorber

2014 ◽  
Vol 670-671 ◽  
pp. 1008-1011 ◽  
Author(s):  
Li Ping Li
Keyword(s):  
High Frequency ◽  
Optimization Design ◽  
Shock Absorber ◽  
Dynamic Stiffness ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Test System ◽  
Test Results ◽  
Static And Dynamic Characteristics ◽  
Rubber Bushing

The experiments of static and dynamic characteristics of rubber bushing for rear suspension telescopic shock absorber were carried out at four directions such as axial, radial, torsion and yaw, by MTS831 and SAGINOMIYA test system. The tests prove that: rubber bushing has great damping, and rubber bushing has obvious nonlinear characteristic; the dynamic stiffness under low frequency and large amplitude excitation is smaller, while the dynamic stiffness under high frequency and small amplitude excitation is greater; at the same amplitude, the dynamic stiffness increases with the increasing excitation frequency. The test results can provide support for the optimization design of rubber bushing.

scholarly journals Analysis of the Vibration Measurement and Reduction Possibilities in Linear Infrastructure for Vacuum Rail Technology

2020 ◽  
Vol 3 (1) ◽  
pp. 450-461
Author(s):  
Tomasz Korbiel ◽  
Rafał Rumin ◽  
Jędrzej Blaut ◽  
Stefan Czerwiński ◽  
Jan Kania
Keyword(s):  
Monitoring System ◽  
High Speed ◽  
Reduction Method ◽  
Vibration Reduction ◽  
Vibration Monitoring ◽  
Vibration Measurement ◽  
Research Centers ◽  
High Speed Rail ◽  
Linear Infrastructure ◽  
Variable Characteristic

Abstract The paper presents the concept of vibration measurement and reduction system for rails in hyperloop technology. It is based on the experience of measuring vibrations in high-speed rail, the first commercial magnetic rail, and vibration reduction systems for these rails. The authors outlined a conceptual vibration monitoring system based on the MQTT protocol and the vibration reduction method. The vibration reduction systems based on variable-characteristic silencers and solutions used in research centers, especially in CERNie and LIGO, were de-scribed.

scholarly journals Fatigue Performance of the CA Mortar Used in CRTS I Ballastless Slab Track under Simulated Servicing Condition

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2259 ◽  
Author(s):  
Yuchuan Shan ◽  
Shuguang Zheng ◽  
Xuefeng Zhang ◽  
Wei Luo ◽  
Jingda Mao ◽  
...  
Keyword(s):  
Fatigue Test ◽  
High Frequency ◽  
High Speed ◽  
Comfort Level ◽  
Polymer Emulsion ◽  
High Speed Railway ◽  
High Frequency Vibration ◽  
Vibration Load ◽  
Slab Track ◽  
Ca Mortar

The cement and asphalt mortar (CA mortar) used in the China Railway Track System (CRTS) I ballastless slab track may encounter a coupling fatigue effect under the high-frequency vibration, load and high-and-low temperature cycles, and the deterioration under fatigue may happen during service of the high-speed railway. In this study, the performance degradation and its mechanism of the CA mortar with and without polymer emulsion incorporated under the coupling fatigue effects of the high-frequency vibration, load and temperature were studied by using an anti-fatigue testing device specially developed for the CA mortar used in the ballastless slab track of the high-speed railway. The results showed that the deformation capacity of the CA mortar for CRTS I slab ballastless slab track decreased after fatigue test under simulated service environment, presenting a typical brittle characteristic and an obvious reduction of the ductility and toughness. The Scanning Electron Microscopy (SEM) observation and the mercury intrusion porosimetry (MIP) analysis showed that the volume of the macropore decreased whereas that of the micropore increased after the fatigue test. The asphalt in the hardened CA mortar revealed a softening and migration from the bulk paste to fill the pore and make the structure denser and even ooze out of the CA mortar under the high-frequency vibration and high temperature. Through incorporating the polymer emulsion, the anti-fatigue property of the CA mortar was obviously improved, which can prevent the CA mortar from losing its elastic adjustment function too early. Though increase of the strength and elastic modulus for the CA mortar after severe service is beneficial to the stability of train running, the comfort level and safety of the train operation may decline due to the gradual reduction of the ductility & toughness and the gradual loss of the elastic damping adjustment function of the CA mortar between the base concrete slab and the track slab.

scholarly journals Vision-Based Faint Vibration Extraction Using Singular Value Decomposition

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Xiujun Lei ◽  
Jie Guo ◽  
Chang’an Zhu
Keyword(s):  
Singular Value Decomposition ◽  
High Speed ◽  
Singular Value ◽  
Vibration Measurement ◽  
Displacement Sensor ◽  
Remote Measurement ◽  
Engineering Structures ◽  
High Speed Rail ◽  
Sound Barrier ◽  
Value Decomposition

Vibration measurement is important for understanding the behavior of engineering structures. Unlike conventional contact-type measurements, vision-based methodologies have attracted a great deal of attention because of the advantages of remote measurement, nonintrusive characteristic, and no mass introduction. It is a new type of displacement sensor which is convenient and reliable. This study introduces the singular value decomposition (SVD) methods for video image processing and presents a vibration-extracted algorithm. The algorithms can successfully realize noncontact displacement measurements without undesirable influence to the structure behavior. SVD-based algorithm decomposes a matrix combined with the former frames to obtain a set of orthonormal image bases while the projections of all video frames on the basis describe the vibration information. By means of simulation, the parameters selection of SVD-based algorithm is discussed in detail. To validate the algorithm performance in practice, sinusoidal motion tests are performed. Results indicate that the proposed technique can provide fairly accurate displacement measurement. Moreover, a sound barrier experiment showing how the high-speed rail trains affect the sound barrier nearby is carried out. It is for the first time to be realized at home and abroad due to the challenge of measuring environment.

scholarly journals Power Electronic Transformer based IGBT Converters for Electric Locomotive Applications

2019 ◽  
Vol 9 (2) ◽  
pp. 3346-3351
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Power Converter ◽  
Power Electronic ◽  
Electric Locomotive ◽  
High Speed Rail ◽  
Line Frequency ◽  
Electronic Transformer ◽  
High Frequency Transformer ◽  
Traction Drives

Electric locomotives up gradation is one of fastest growing technology on railway research. Modern locomotive traction drives operate for high speed rail networks. This paper proposes locomotive drives directly from the mains without line frequency locomotive transformer. Power electronic transformers (PETs) offer the advantage of the reduction in size and weight compared to conventional line frequency transformers. In this article discussed about high power converter using IGBT with high-frequency transformer for electric locomotives is utilized for the power converter side. The catenary feeding front end of the locomotive is connected directly to IGBT based cascade H bridge converter and conventional IGBT based three phase inverter act as load end converter for driving induction motor. The MATLAB simulation results of PET based high frequency transformer with IGBT power converter integrated with traction inverter has justified .

scholarly journals Key Factors of the Initiation and Development of Polygonal Wear in the Wheels of a High-Speed Train

2020 ◽  
Vol 10 (17) ◽  
pp. 5880
Author(s):  
Yue Wu ◽  
Xuesong Jin ◽  
Wubin Cai ◽  
Jian Han ◽  
Xinbiao Xiao
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Interaction Force ◽  
Key Factors ◽  
Resonant Frequencies ◽  
Operation Speed ◽  
High Speed Trains ◽  
Train Operation ◽  
Flexible Deformation ◽  
Polygonal Wear

The polygonal wear of train wheels occurs commonly in rail transport and increases the wheel–rail interaction force dramatically and has a bad effect on the safety and comfort of the train. The mechanism of polygonal wear needs to be studied. The characteristics of test data measured from 47,000 sets of polygonal wheels of high-speed trains were analysed statistically. The analysis shows that, in the entire use life cycle of the wheels, the order (wavelength) and development speed of polygonal wear are different; they correspond to different wheel diameters because of wear and re-profiling. A prediction model, which considered the flexibility of the wheelset for the polygonal wear of the wheels of high-speed trains, was developed to explain this phenomenon. This theoretical model analyses the initiation, development, and characteristics of polygonal wear. The analysis includes the effect of the high-frequency flexible deformation of the wheelset, train operation speed, and wheel diameter variation. This study suggests that, if the wheel perimeter is nearly an integral multiple of the wavelength of severe periodic wear along the wheel circumference, the polygonal wear on the wheel can develop quickly. Furthermore, the wavelength of the periodic wear of the wheel relies on the operation speed of the train and wheelset resonant frequency. Therefore, the initiation and development of polygonal wear on wheels depends on the operation speed, wheel diameter, and the resonant frequencies of the wheelset. This conclusion can be applied to research concerning measures associated with the suppression of polygonal wear development.

Advanced High Frequency In-Bit Vibration Measurement Including Independent, Spatially Separated Sensors for Proper Resolution of Vibration Components Including Lateral, Radial, and Tangential Acceleration

2021 ◽  
Author(s):  
Todd Townsend ◽  
Will Moss ◽  
Dennis Heinisch ◽  
Kenneth Evans ◽  
Cecil Schandorf
Keyword(s):  
Flash Memory ◽  
High Frequency ◽  
High Speed ◽  
Angular Acceleration ◽  
Vibration Measurement ◽  
Outer Diameter ◽  
Stick Slip ◽  
Torsional Oscillations ◽  
Sample Rate ◽  
Tangential Acceleration

Abstract Vibration measurement has become ubiquitous in drilling. Focus of drilling enhancement has expanded from traditional lateral and stick slip assessment to include torsional oscillations on motors, and high-frequency torsional oscillations (HFTO). Recent publications have highlighted the importance of these higher frequency measurements to analyze drilling dynamics and diagnose dysfunctions which can cause tool failures. A new vibration recorder will be presented which is capable of sampling at 2 kHz and higher to analyze non-linear transient dysfunctions. Most in-bit vibration measurement options utilize a single unsynchronized triaxial accelerometer and low speed gyro. This design practice inherits specific challenges to the measurement and prevents the ability to decouple lateral from angular acceleration. Use of two sets of symmetrically placed (180 degree opposing) accelerometers has been in practice, but design constraints limit this approach to larger bits. Utilization of a new, outer diameter (OD) mounted vibration recorder for slim hole bits/BHAs with multiple spatially separated triaxial accelerometers, and a high-speed precision gyro will be described and evaluated with a comparison to other commercially available options. Downhole vibration recorders have existed for over 20 years providing conventional drilling dynamics evaluation. These devices suffered from hardware limitations which constrained the customer to spaced out snapshots of time rather than continuous observation and required separate research modules to cover high frequency needs. This paper presents case studies utilizing a new vibration recorder which can cover these two customer needs in one device. Drilling Engineers desire a rapid turnaround macro view of synchronized downhole and surface data for offset well parameter optimization while research engineers desire a micro view with kilohertz range sample rate for a comprehensive understanding of all possible dysfunctions including HFTO, and high frequency shock, along with the capacity to research geology prediction techniques including fracture identification. Use of an advanced cloud-based software suite will be illustrated for a rapid high-level view of the full run with benchmarking capability of offset wells. Case study observations include stick slip identification covering 0 to above 600 rpm using a single gyroscope, and HFTO identification with accurate decoupling of tangential acceleration vs radial and lateral. Having the ability to satisfy both objectives with one device is new to the industry and presents a step change in capability. A new, advanced vibration recorder is detailed which includes synchronized, spatially separated triaxial accelerometers, a triaxial shock sensor, a highspeed triaxial gyroscope, and temperature sensors. With 5 gigabytes of high temperature flash memory, more than 2 kHz sample rate for burst data and 1s period for downhole processed data, logged downhole recordings can cover greater than 200 hrs of drilling and may be available for analysis within minutes from drilling completion.

Real Ear Sound Pressure Levels Developed by Three Portable Stereo System Earphones

1992 ◽  
Vol 1 (4) ◽  
pp. 52-55 ◽  
Author(s):  
Gail L. MacLean ◽  
Andrew Stuart ◽  
Robert Stenstrom
Keyword(s):  
High Frequency ◽  
Sound Pressure ◽  
Low Frequency ◽  
Test System ◽  
Output Frequency ◽  
Frequency Effects ◽  
Adult Men ◽  
Frequency Responses ◽  
Significant Difference ◽  
Sound Pressure Levels

Differences in real ear sound pressure levels (SPLs) with three portable stereo system (PSS) earphones (supraaural [Sony Model MDR-44], semiaural [Sony Model MDR-A15L], and insert [Sony Model MDR-E225]) were investigated. Twelve adult men served as subjects. Frequency response, high frequency average (HFA) output, peak output, peak output frequency, and overall RMS output for each PSS earphone were obtained with a probe tube microphone system (Fonix 6500 Hearing Aid Test System). Results indicated a significant difference in mean RMS outputs with nonsignificant differences in mean HFA outputs, peak outputs, and peak output frequencies among PSS earphones. Differences in mean overall RMS outputs were attributed to differences in low-frequency effects that were observed among the frequency responses of the three PSS earphones. It is suggested that one cannot assume equivalent real ear SPLs, with equivalent inputs, among different styles of PSS earphones.

Research on Prediction of High-Speed Rail Trains Delay Time

CICTP 2020 ◽  
2020 ◽  
Author(s):  
Jing Shi ◽  
Qiyuan Peng ◽  
Ling Liu
Keyword(s):  
Delay Time ◽  
High Speed ◽  
High Speed Rail
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