scholarly journals In-Service Detection and Quantification of Railway Wheel Flat by the Reflective Optical Position Sensor

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4969
Author(s):  
Run Gao ◽  
Qixin He ◽  
Qibo Feng ◽  
Jianying Cui
Keyword(s):  
High Speed ◽  
Detection System ◽  
Quantitative Relationship ◽  
Real Field ◽  
Position Sensor ◽  
Analysis Model ◽  
Railway Wheel ◽  
Optical Position ◽  
Wheel Flat ◽  
The Impact

Railway wheel tread flat is one of the main faults of railway wheels, which brings great harm to the safety of vehicle operation. In order to detect wheel flats dynamically and quantitatively when trains are running at high speed, a new wheel flat detection system based on the self-developed reflective optical position sensor is demonstrated in this paper. In this system, two sensors were mounted along each rail to measure the wheel-rail impact force of the entire circumference by detecting the displacement of the collimated laser spot. In order to establish a quantitative relationship between the sensor signal and the wheel flat length, a vehicle-track coupling dynamics analysis model was developed using the finite element method and multi-body dynamics method. The effects of train speed, load, wheel flat lengths, as well as the impact positions on impact forces were simulated and evaluated, and the measured data can be normalized according to the simulation results. The system was assessed through simulation and laboratory investigation, and real field tests were conducted to certify its validity and correctness. The system can determine the position of the flat wheel and can realize the quantification of the detected wheel flat, which has extensive application prospects.

scholarly journals Flexible-Rigid Wheelset Introduced Dynamic Effects due to Wheel Tread Flat

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Awel Momhur ◽  
Y. X. Zhao ◽  
Liwen Quan ◽  
Sun Yazhou ◽  
Xialong Zou
Keyword(s):  
High Speed ◽  
Statistical Approach ◽  
Impact Load ◽  
Vertical Acceleration ◽  
Vehicle Speed ◽  
Dynamic Impact ◽  
Element Analysis ◽  
Wheel Flat ◽  
Wheel Radius ◽  
The Impact

The widespread faults that occur in railway wheels and can cause a massive dynamic impact are the wheel tread flat. The current work considered changes in vehicle speed or wheel radius deviation and studied the dynamic impact load. The modal technique for the impact evaluation induced by the wheel flat was proposed via the finite element analysis (FEA) software package ANSYS, integrated into a multibody dynamics model of the high-speed train CRH2A (EMU) through SIMPACK. The irregularity track line has developed and depends on the selected simulation data points. Additionally, a statistical approach is designed to analyze the dynamic impact load response and effect and consider different wheel flat lengths and vehicle speeds. The train speed influence on the flat size of the vertical wheel-rail impact response and the statistical approach are discussed based on flexible, rigid wheelsets. The results show that the rigid wheel flat has the highest vertical wheel impact load and is more significant than the flexible wheel flat force. The consequences suggest that the wheelset flexibility can significantly improve vertical acceleration comparably to the rigid wheel flats. In addition, the rendering of the statistical approach shows that the hazard rate, PDF, and CDF influence increase when the flat wheel length increases.

Reinvestigation into railway wheel-track interaction and suspension damage

2020 ◽  
pp. 095440972093202
Author(s):  
Renfan Luo ◽  
David Vincent
Keyword(s):  
High Speed ◽  
Sensitivity Study ◽  
Hertzian Contact ◽  
Contact Theory ◽  
Fe Model ◽  
Fe Modelling ◽  
Wheel Flat ◽  
The Impact ◽  
Hertzian Contact Theory ◽  
Wheel Track

Without considering either velocity or acceleration effects, the current conventional method presented in literature applies the vertical deflection of a wheel centre caused by a flat defect to the Hertzian contact theory. This method has been numerically and theoretically proved to be inappropriate and can incorrectly predict a higher wheel-rail impact force for a low speed than a high speed. Therefore, under a hypothesis of no wheel bouncing and sliding, two new methods, the velocity-based and the acceleration-based have been proposed. The former method takes the wheel centre deflection change in each computational increment from the Hertzian contact theory while the latter applies the wheel centre acceleration caused by the flat in revolutions to the wheel as a force in dynamic simulation, which interprets the speed effects on impacts precisely. A sensitivity study proves that the velocity-based method is unreliable as opposed to the acceleration-based method. A beam/rigid FE model has also been developed to inspect the wheel-track interaction by performing dynamic analysis in the time domain. It has been found out that the impact responses predicted by the FE analysis and the velocity method are similar and the FE results heavily depend on the compute increment, which implies the FE modelling in ABAQUS may be unreliable for this issue with current applied increments. Finally, the results calculated using the acceleration method have been employed to study the suspension/damper torsional stress caused by a wheel flat. This indicates that a wheel flat may lead to potential fatigue damage if without proper maintenance management.

Dynamic Analysis of Pitch Plane Railway Vehicle-Track Interactions Due to Single and Multiple Wheel Flats

2008 ◽  
Author(s):  
Rajib Ul Alam Uzzal ◽  
Subhash Rakheja ◽  
Waiz Ahmed
Keyword(s):  
Parametric Study ◽  
High Speed ◽  
Impact Load ◽  
Critical Length ◽  
Hertzian Contact ◽  
Railway Vehicle ◽  
Main Concern ◽  
Track System ◽  
Wheel Flat ◽  
The Impact

The dynamic impact forces due to the wheel defect such as a flat is a main concern for a heavy freight train operating at high speed. The present investigation employs a pitch plane vehicle model coupled with a comprehensive three-layer track system model to study the impact force generated in the wheel-rail interface due to the presence of wheel flats. The wheel-rail contact is modeled using nonlinear Hertzian contact theory. Responses in terms of wheel-rail impact load and forces transmitted to bearings, pad and ballast are evaluated in an attempt to identify desirable design and operating factors. Wheel-rail impact loads due to the presence of multiple flats either in single or different wheels in-phase or out-of-phase conditions are evaluated and analyzed. A detailed parametric study is carried out that includes the variations in selected vehicle, track, operational as well as flat parameters. The results show that the effect of multiple flats is insignificant if they are more than 45° apart. The impact due to single wheel flat can be larger than in-phase flats at each wheel due to the presence of pitch dynamics. The parametric study shows that other than speed, depth and length of the flats are most sensitive parameters, and there exists a critical length at each flat depth that leads to the largest impact load.

scholarly journals Design of a system solution that modernizes legacy supervisory control and data acquisition systems as an early detection system

2018 ◽  
Vol 51 (7-8) ◽  
pp. 205-212 ◽  
Author(s):  
Beşir Demir ◽  
Ahmet Tumay ◽  
Mehmet Efe Ozbek ◽  
Enver Cavus
Keyword(s):  
Early Detection ◽  
Data Acquisition ◽  
Supervisory Control ◽  
High Speed ◽  
Data Transfer ◽  
Detection System ◽  
Data Acquisition Systems ◽  
Gateway System ◽  
System Solution ◽  
The Impact

Background In industrial disasters, early detection of problems and crisis management are critical for saving the lives of people and reducing the impact of disasters. Purpose In this study, we design a special gateway system that bridges the gap between different communication protocols and enables legacy supervisory control and data acquisition systems to function early detection systems for potential industrial disasters. Methods The system uses a new queue mechanism to substantially improve the problem of data loss found in conventional supervisory control and data acquisition systems and utilizes identification (ID) prioritization to enable early detection of problems. The proposed system is implemented and tested on a Linux-based, 3G-capable Modbus gateway system. Modbus is used as the communication protocol and 3G technology is utilized to provide high-speed wireless data transfer components. The Modbus gateway device uses an ARM-based EP9302 processor and has digital input/output, relay outputs, and RS485 outputs. Conclusion This study is significant as it is the first work to show the application of the priority query execution method for Modbus gateway devices.

Research on the EM Modeling of Optimization of PCB Grounded Via

2012 ◽  
Vol 195-196 ◽  
pp. 1153-1157
Author(s):  
Liang Qi Gui ◽  
Cao Yang ◽  
Jia He ◽  
Xiao Ping Gao ◽  
Ke Chen ◽  
...  
Keyword(s):  
High Speed ◽  
Signal Transmission ◽  
Wave Model ◽  
Simulation Software ◽  
Design Parameters ◽  
Optimized Design ◽  
Analysis Model ◽  
Scattering Parameter ◽  
Full Wave ◽  
The Impact

Grounded vias modeling is used to analyze the impact on the high speed PCB EMC and SI issues in three aspects, including theoretical analysis, simulator modeling and practical PCB test. In this paper, we discuss the full-wave complex scattering parameter model and full-wave model. Then the full-wave analysis model of the through holes for model validation and comparison are established, by using numerical simulation software HFSS and CST Microwave Studio. The initial test results on the practical PCB show that the analyzed method is reasonable and accurate. And optimized design parameters can ensure the continuity of the impedance of vias, and introduce lesser return loss and insertion loss. It is shown that the signal transmission performance is greatly improved with the grounded via added, which is helpful in specifying the manufacturing tolerance of via designs.

Effect of roller dynamic unbalance on cage stress of high-speed cylindrical roller bearing

2018 ◽  
Vol 70 (9) ◽  
pp. 1580-1589 ◽  
Author(s):  
Yongcun Cui ◽  
Sier Deng ◽  
Yanguang Ni ◽  
Guoding Chen
Keyword(s):  
High Speed ◽  
Roller Bearing ◽  
Radial Clearance ◽  
Analysis Model ◽  
Element Analysis ◽  
Content Type ◽  
Cylindrical Roller Bearing ◽  
The Impact ◽  
Cylindrical Roller ◽  
Dynamic Unbalance

Purpose The purpose of this study is to investigate the effect of roller dynamic unbalance on cage stress. Design/methodology/approach Considering the impact of roller dynamic unbalance, the dynamic analysis model of high-speed cylindrical roller bearing is established. And then the results of dynamic model are used as the boundary conditions for the finite element analysis model of roller and cage to obtain the cage stress. Findings Roller dynamic unbalance affects the contact status between roller and cage pocket and causes the overall increase in cage stress. The most significant impact on cage stress is roller dynamic unbalance in angular direction of roller axis, followed by radial and axial directions. Smaller radial clearance of bearing and a reasonable range of pocket clearance are beneficial to reduce the impact of roller dynamic unbalance on cage stress; the larger cage guide clearance is a disadvantage to decrease cage stress. The impact of roller dynamic unbalance on cage stress under high-speed condition is greater than that in low-speed conditions. Originality/value The research can provide some theoretical guidance for the design and manufacture of bearing in high-speed cylindrical roller bearing.

scholarly journals Railway Wheel Flat Detection System Based on a Parallelogram Mechanism

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3614 ◽  
Author(s):  
Run Gao ◽  
Qixin He ◽  
Qibo Feng
Keyword(s):  
Detection System ◽  
Field Measurements ◽  
Measuring System ◽  
Detection Methods ◽  
Model Parameters ◽  
Detection Accuracy ◽  
Railway Wheel ◽  
Measuring Mechanism ◽  
Train Speed ◽  
Wheel Flat

Wheel flats are a key fault in railway systems, which can bring great harm to vehicle operation safety. At present, most wheel flat detection methods use qualitative detection and do not meet practical demands. In this paper, we used a railway wheel flat measurement method based on a parallelogram mechanism to detect wheel flats dynamically and quantitatively. Based on our experiments, we found that system performance was influenced by the train speed. When the train speed was higher than a certain threshold, the wheel impact force would cause vibration of the measuring mechanism and affect the detection accuracy. Since the measuring system was installed at the on-site entrance of the train garage, to meet the speed requirement, a three-dimensional simulation model was established, which was based on the rigid-flexible coupled multibody dynamics theory. The speed threshold of the measuring mechanism increased by the reasonable selection of the damping coefficients of the hydraulic damper, the measuring positions, and the downward displacements of the measuring ruler. Finally, we applied the selected model parameters to the parallelogram mechanism, where field measurements showed that the experimental results were consistent with the simulation results.

scholarly journals An Automatic Fault Recognition Method for Side Frame Key in TFDS

2015 ◽  
Vol 9 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Guodong Sun ◽  
Wei Feng ◽  
Daxing Zhao ◽  
Linjie Yang
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Detection System ◽  
Region Of Interest ◽  
Recognition Method ◽  
Fiber Network ◽  
Car Detection ◽  
Fault Recognition ◽  
The Impact ◽  
Through Hole

Trouble of moving Freight car Detection System (TFDS) constitutes an important part of the railway safety warning systems. With TFDS, dynamic images of freight cars are captured by high-speed cameras, timely transmitted to the train inspection center by special optical fiber network and finally observed for fault recognition. In this paper, an automatic fault recognition method for side frame key in TFDS is proposed based on open source computer vision library (OpenCV) to overcome the disadvantages of manual fault recognition. At first, image preprocessing and segmentation are applied to eliminate the impact of the surrounding environment and further simplify images. Then the axle and through-hole are calibrated through Hough circle transformation and the side frame key is located indirectly according to the geometric relationship among the axle, through-hole and side frame key. Finally, the difference of mean gray values in the region of interest (ROI) is analyzed to judge whether the side frame key is missing or not. Featured by the high efficiency, reliability and practicability, the proposed method lays the foundation for engineering applications in automatic fault recognition of freight cars.

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