scholarly journals Study on Train Wheel Out-of-Roundness Monitoring Method by PVDF Sensing Technology

2014 ◽  
Vol 8 (1) ◽  
pp. 77-80
Author(s):  
Ying Song ◽  
Zhichen Wang ◽  
Yanliang Du
Keyword(s):  
Visual Inspection ◽  
Strain Sensor ◽  
Condition Index ◽  
Contact Forces ◽  
Strain Response ◽  
Element Analysis ◽  
Monitoring Method ◽  
Sensing Technology ◽  
Train Speed ◽  
Set Up

Wheel out-of-roundness (OOR) inevitably jeopardizes the safety of railway operations. Regular visual inspection and checking by experienced workers are the commonly adopted practices to identify wheel defects. However, the defects may not be spotted timely. The paper puts forward a new method of real-time monitor wheel OOR based on PVDF strain sensor. In this method, the track strain response upon wheel-rail interaction is measured and processed to generate a condition index which directly reflects the wheel condition. Firstly, theoretical model of relationship between PVDF sensor output and wheel/rail loads was set up, and the principle for measuring vertical wheel/rail contact forces was proposed. Secondly, the effects of horizontal wheel/rail force and train speed on the output results have been discussed. Finally, this approach was verified by finite element analysis, and the preliminary results showed that this electromagnetic-immune system provides an effective alternative for wheel defects’ detection.

Study on Wheel/Rail Interaction Force Real-Time Monitoring Method Based on Piezoelectric Sensing Technology

2009 ◽  
Vol 79-82 ◽  
pp. 7-10 ◽  
Author(s):  
Ying Song ◽  
Yan Liang Du ◽  
Bao Chen Sun
Keyword(s):  
High Speed ◽  
Force Measurement ◽  
Interaction Force ◽  
Test System ◽  
Contact Forces ◽  
Strain Gauges ◽  
Strain Sensing ◽  
Monitoring Method ◽  
Sensing Technology ◽  
Test Requirements

Measurement of wheel/rail contact forces is of importance. Traditional methods for wheel/rail interaction force measurement all need strain gauges on wheel sets and/or rails. Because strain gauges have the performances of zero-drift, poor anti-interference property and instability of test system, they can’t meet wheel/rail force test requirements in high-speed and heavy haul railways. A new method based on PVDF piezoelectric sensing technology is presented for the test of vertical and horizontal wheel/rail force in this paper. Firstly, based on the wheel/rail interaction characteristics, the restriction condition of track and strain sensing principle of PVDF films, principle for measuring vertical and lateral wheel/rail interaction forces is proposed. Then a series of tests were carried out to compare the performance of PVDF strain sensors with the one of strain gauges. The results show that the PVDF strain sensor has better reliability in wheel/rail force monitoring. Finally numerical analysis by Finite Element Method has been carried out to verify the feasibility of the method presented in this paper.

scholarly journals Mechanical Response of Four-Bar Linkage Microgrippers with Bidirectional Electrostatic Actuation

Actuators ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 78 ◽  
Author(s):  
Fabio Botta ◽  
Matteo Verotti ◽  
Alvise Bagolini ◽  
Pierluigi Bellutti ◽  
Nicola Belfiore
Keyword(s):  
Mechanical Response ◽  
Numerical Study ◽  
Electrostatic Actuation ◽  
Contact Forces ◽  
Mechanical Resistance ◽  
Element Analysis ◽  
Comb Drives ◽  
System Vibration ◽  
Set Up ◽  
Four Bar Linkage

This paper presents both an experimental and a numerical study concerning the mechanical response of a silicon microgripper with bidirectional electrostatic actuation to externally applied excitations. The experimental set-up is composed of a probe station equipped with mobile probes that apply contact forces. This part of the investigation aims to test the device’s mechanical resistance, its mobility capability and possible internal contacts during the system deformation. The second part of the paper is dedicated to the study of the free undamped vibrations of the microsystem. Finite Element Analysis (FEA) is carried out to evaluate the system vibration modes. The analysis of the modes are useful to predict possible mechanical interference among floating and anchored fingers of the actuating comb drives.

Finite Element Analysis of Large-Size Yaw Bearings with Supporting Structure in Wind Turbine

2014 ◽  
Vol 672-674 ◽  
pp. 1550-1553
Author(s):  
Zhen Guo Shang ◽  
Zhong Chao Ma ◽  
Zhen Sheng Sun
Keyword(s):  
Finite Element ◽  
Wind Turbine ◽  
Point Contact ◽  
Element Model ◽  
Contact Forces ◽  
Element Analysis ◽  
Supporting Structure ◽  
Rolling Elements ◽  
Yaw Bearing ◽  
Compression Springs

A procedure for obtaining the load distribution in a four point contact wind turbine yaw bearing considering the effect of the structure’s elasticity is presented. The inhomogeneous stiffness of the supporting structures creates a variation in the results obtained with a rigid model. A finite element model substituting the rolling elements with nonlinear compression springs has been built to evaluate the effect of the supporting structure elasticity on the contact forces between the rolling elements and the raceways.

scholarly journals Real-Time Train Wheel Condition Monitoring by Fiber Bragg Grating Sensors

2011 ◽  
Vol 8 (1) ◽  
pp. 409048 ◽  
Author(s):  
Chuliang Wei ◽  
Qin Xin ◽  
W. H. Chung ◽  
Shun-yee Liu ◽  
Hwa-yaw Tam ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Real Time ◽  
Visual Inspection ◽  
Condition Index ◽  
Bragg Grating ◽  
Time System ◽  
Real Time System ◽  
Fiber Bragg Grating Sensors ◽  
Extensive Field ◽  
The Cost

Wheel defects on trains, such as flat wheels and out-of-roundness, inevitably jeopardize the safety of railway operations. Regular visual inspection and checking by experienced workers are the commonly adopted practice to identify wheel defects. However, the defects may not be spotted in time. Therefore, an automatic, remote-sensing, reliable, and accurate monitoring system for wheel condition is always desirable. The paper describes a real-time system to monitor wheel defects based on fiber Bragg grating sensors. Track strain response upon wheel-rail interaction is measured and processed to generate a condition index which directly reflects the wheel condition. This approach is verified by extensive field test, and the preliminary results show that this electromagnetic-immune system provides an effective alternative for wheel defects detection. The system significantly increases the efficiency of maintenance management and reduces the cost for defects detection, and more importantly, avoids derailment timely.

scholarly journals Finite Element Analysis of Stress-Strain Response at the Tool Pin During Friction Stir Process

2015 ◽  
Vol 76 ◽  
pp. 522-527
Author(s):  
M. Shamil Jaffarullah ◽  
Nur’Amirah Busu ◽  
Cheng Yee Low ◽  
J.B. Saedon ◽  
Armansyah ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Response ◽  
Stress Strain ◽  
Element Analysis ◽  
Friction Stir Process ◽  
Friction Stir ◽  
Tool Pin

scholarly journals Structural Health Monitoring Method of Pantograph–Catenary System Based on Strain Response Inversion

2021 ◽  
Vol 9 ◽  
Author(s):  
Sheng Liu ◽  
Yibo Wei ◽  
Yongxin Yin ◽  
Tangzheng Feng ◽  
Jinbao Lin
Keyword(s):  
Structural Health Monitoring ◽  
Contact Force ◽  
Health Monitoring ◽  
Data Consistency ◽  
Inversion Method ◽  
Maximum Speed ◽  
Strain Response ◽  
Monitoring Method ◽  
Structural Health ◽  
Catenary System

Pantograph-catenary system provides electric energy for the subway lines; its health status is essential to the serviceability of the vehicle. In this study, a real-time structural health monitoring method based on strain response inversion is proposed to calculate the magnitude and position of the dynamic contact force between the catenary and pantograph. The measurement principle, calibration, and installation detail of the fiber Bragg grating (FBG) sensors are also presented in this article. Putting this monitoring system in use, an application example of a subway with a rigid overhead catenary is given to demonstrate its performance. The pantograph was monitored and analyzed, running underground at a maximum speed of 80 km/h. The results show that the strain response inversion method has high measurement accuracy, good data consistency, and flexibility on sensor installation. It can accurately calculate the magnitude and location of the contact force exerted on the pantograph.

scholarly journals Failure Analysis of fractured Fixing Bolts of a Mobile Elevating Work Platform using Finite Element Methods

2019 ◽  
Author(s):  
DongHoon Choi ◽  
Jae-Hoon Kim
Keyword(s):  
Finite Element ◽  
Chemical Composition ◽  
Chemical Analysis ◽  
Failure Analysis ◽  
Visual Inspection ◽  
Standard Procedure ◽  
Fatigue Analysis ◽  
Certification Authority ◽  
Element Analysis ◽  
Safety Certification

Mobile elevating work platforms (MEWPs) consist of a work platform, extending structure, and chassis, and are used to move persons to working positions. MEWPs are useful but are composed of pieces of equipment, and accidents do occur owing to equipment defects. Among these defects, accidents caused by the fracture of bolts fixed to the extension structure and swing system are increasing. This paper presents a failure analysis of the fixing bolts of MEWP. Standard procedure for failure analysis was employed in this investigation. Visual inspection, chemical analysis, tensile strength measurement, and finite element analysis (FEA) were used to analyze the failure of the fixing bolts. Using this failure analysis approach, we found the root cause of failure and proposed a means for solving this type of failure in the future. First, the chemical composition of the fixing bolt is obtained by a spectroscopy chemical analysis method, which determined that the chemical composition matched the required standard. The tensile test showed that the tensile and yield strengths were within the required capacity. The stress analysis was carried out at five different boom angles, and it was determined that the fixing bolt of MEWP can withstand the loads at all the boom angles. The outcomes of the fatigue analysis revealed that the fixing bolt fails before reaching the design requirements. The results of the fatigue analysis showed primarily that the failure of the fixing bolt was due to fatigue. A visual inspection of the fractured section of the fixing bolt also confirmed the fatigue failure. We propose a method to prevent failure of the fixing bolt of the MEWP from four different standpoints: the manufacturer, safety certification authority, safety inspection agency, and owner.

scholarly journals A MONITORING METHOD OF COLOR DECAYING FOR COLORED PATTERNS IN ARCHITECTURAL HERITAGE

2019 ◽  
Vol XLII-2/W11 ◽  
pp. 1193-1198
Author(s):  
L. Zhang ◽  
J. Xie ◽  
L. Qin ◽  
Z. Liu ◽  
G. Liu
Keyword(s):  
Good Health ◽  
Color Difference ◽  
Health Condition ◽  
Architectural Heritage ◽  
Monitoring Method ◽  
Special Part ◽  
Color Differences ◽  
The Status ◽  
Set Up ◽  
Colored Pattern

<p><strong>Abstract.</strong> As a special part of architectural heritage, the colored pattern is not only artwork to decorate the architecture, but information reflecting specific historical era. So it has great cultural and artistic value. However, the colored pattern is one of the most sensitive types of cultural relics, which is sensitive to natural environment changes and highly vulnerable to erosion. In order to strengthen the protection of colored patterns in history architectures, it is necessary to monitor the status quo of them.</p><p>This work introduces a monitoring method of color decaying for colored patterns in architecture: set up the illuminants, adjust the illuminants, detect the color information and calculate the color difference. Based on the color difference by CIE DE2000 formula, the color decaying status of the pattern can be evaluated. The monitoring period should be at least three months.</p><p>About four years’ work has been carried out for colored patterns in the Long Corridor of the Summer Palace, and the color differences &amp;Delta;E<sub>00</sub> are about from 2 to 5, some can be over 9. In result, most colored patterns keep in good health condition. Color decaying happens every time and there are slight changes in most colored patterns. In 2nd quarter 2017, aware changes happened in nearly all the patterns. According to the color difference to evaluate the color decaying of the colored patterns, it is an efficient method to analyze the health status of colored patterns.</p>

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