Monitoring of Rail-Wheel Interaction Using Acoustic Emission (AE)

2006 ◽  
Vol 13-14 ◽  
pp. 161-168 ◽  
Author(s):  
N.A. Thakkar ◽  
John A. Steel ◽  
R.L. Reuben ◽  
G. Knabe ◽  
D. Dixon ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Contact Fatigue ◽  
Field Measurements ◽  
Vehicle Speed ◽  
Moving Sources ◽  
Wave Characteristics ◽  
Sensor Position ◽  
Single Sensor ◽  
Interaction Intensity ◽  
Good Agreement

This work presents the results of field measurements and laboratory studies carried out with a view to developing ways to monitor rail-wheel interaction using Acoustic Emission. It is known that impact, wear and cracking generate AE and it is therefore expected that axle loads, wheel out-of-roundness, speed and traction will influence the AE generated by an interaction. It is hoped that the extent of the effect might be sufficient to permit a measure of “interaction intensity” that could be used to quantify cumulative damage by wear and contact fatigue. In the field measurements, AE was acquired as a train with 20 moving sources of AE (20 wheels) passed a single sensor position and a laboratory rig has been devised which uses a single wheel whose condition, speed and loading can conveniently be modified. Simulated source tests have indicated that the AE wave characteristics on real rails are similar to those in the laboratory rig. A simplified analytical model, devised for AE waves propagating from a moving source(s), based on a ‘vehicle’ speed and wave damping coefficients, has been compared to measured results. As a wheel rolls towards a sensor and then away from the sensor the measured AE generally rises and falls in a predictable way. The effects of wheel and rail surface features appear to complicate the results by introducing sharp spikes in the signals. The numerical model for AE wave propagation from the moving sources (wheels) shows good agreement with the more slowly changing envelope of the signals.

Simulation and Field Testing of Tracked Vehicle Suspension Dynamics

1994 ◽  
Vol 116 (4) ◽  
pp. 764-773 ◽  
Author(s):  
S. Sankar ◽  
A. Dhir ◽  
V. S. Shankhla
Keyword(s):  
Field Measurements ◽  
Field Testing ◽  
Vehicle Suspension ◽  
Vehicle Speed ◽  
Tracked Vehicle ◽  
Suspension Dynamics ◽  
Dynamic Simulation Model ◽  
Vehicle Suspension Dynamics ◽  
Good Agreement ◽  
Wheel Track

A nonlinear, in-plane ride dynamic simulation model of a typical off-road tracked vehicle is developed assuming constant forward vehicle speed and nondeformable terrain surface. The ride model includes nonlinear suspension characteristics, wheel/track-terrain interactions, and dynamic track loads. An equivalent damper and continuous radial spring formulation is employed to model wheel/track-terrain interactions, whereas dynamic track loads are modeled in view of track belt stretching and initial track tension. Typical simulation results are presented for a conventional armoured personnel carrier traversing discrete half round obstacles, and a random course, and are validated against field measurements. The predicted ride responses exhibit generally good agreement with field test data.

Acoustic vehicle speed estimation from single sensor measurements

2021 ◽  
pp. 1-1
Author(s):  
Slobodan Djukanovic ◽  
Jiri Matas ◽  
Tuomas Virtanen
Keyword(s):  
Speed Estimation ◽  
Vehicle Speed ◽  
Single Sensor

scholarly journals THERMAL DIFFUSIVITY MEASUREMENT OF SOLID USING PYROELECTRIC SENSOR

2017 ◽  
Vol 19 (1) ◽  
pp. 91-95
Author(s):  
B. Z. Azmi ◽  
Y. T. Ling ◽  
M. Hashim ◽  
W. M. M. Yunus ◽  
M. M. Moksin
Keyword(s):  
Thermal Diffusivity ◽  
Thermal Wave ◽  
Spectroscopic Technique ◽  
Thermal Diffusivity Measurement ◽  
Pyroelectric Sensor ◽  
Diffusivity Measurement ◽  
Sensor Position ◽  
Aluminium Copper ◽  
Lateral Distance ◽  
Good Agreement

The recently developed pyroelectric spectroscopic technique has been used to measure the thermal diffusivity of solids. The method has been applied to conductors and insulator where by the thermal wave is measured at various lateral distances on the sample between laser illuminated line and pyroelectric sensor position. The thermal diffusivity is obtained from the gradient of the plot of thermal wave signal versus the lateral distance. A good agreement to the previously reported thermal diffusivity value has been obtained for aluminium, copper and spray paint that is 0.809 cm2s-1, 1.128 3cm2s-1 and 1.547 x 10-3 cm2s-1 respectively.

The Application of Ground-airborne TEM Systems for Underground Cavity Detection in China

2018 ◽  
Vol 23 (1) ◽  
pp. 103-113
Author(s):  
Guo-qiang Xue ◽  
Xiu Li ◽  
Sheng-bao Yu ◽  
Wei-ying Chen ◽  
Yan-ju Ji
Keyword(s):  
Three Dimensional ◽  
Field Measurements ◽  
Cavity Detection ◽  
Vector Finite Element Method ◽  
Military Applications ◽  
Vector Finite Element ◽  
Survey Results ◽  
Tem Method ◽  
Central Loop ◽  
Good Agreement

Ground-based, electrical-source, and UAV-borne receiver TEM configurations have previously been used to map mines in Jiangsu Province, China. In this study, the EM responses of air-filled mine tunnels were simulated by using a three-dimensional (3D) vector finite element method. A new apparent resistivity formula has been proposed for the ground-airborne TEM configuration. In the study area, field measurements were carried out along 36 profiles for the ground-airborne TEM and 16 profiles for ground TEM. The ground-airborne TEM results were determined to be in good agreement with the ground TEM survey results using a surface central loop, and were also consistent with the known geologic conditions. The experiment was successful and showed that a ground-ground-airborne TEM method could potentially become a novel alternative for both future civilian and military applications. [Figure: see text]

Design and Analysis of Foldable Vehicle using Finite Element Simulation

2021 ◽  
Vol 13 (3) ◽  
Author(s):  
Vikas Radhakrishna Deulgaonkar ◽  
S.N. Belsare ◽  
Naik Shreyas ◽  
Dixit Pratik ◽  
Kulkarni Pranav ◽  
...  
Keyword(s):  
Finite Element ◽  
Dynamic Properties ◽  
Mode Shapes ◽  
Vehicle Speed ◽  
Element Analysis ◽  
Dynamic Stresses ◽  
Element Simulation ◽  
Vehicle Structure ◽  
Similar Materials ◽  
Good Agreement

Present work deals with evaluation of stress, deflection and dynamic properties of the folded vehicle structure. The folded vehicle in present case is a single seat vehicle intended to carry one person. Design constraints are the folded dimensions of the vehicle and the maximum vehicle speed is limited to 15m/s. Using classical calculations dimensions of the vehicle are devised. Different materials are used for seat, telescopic support and chassis of the foldable vehicle. computer aided model is prepared using CATIA software. Finite element analysis of the foldable vehicle has been carried out to evaluate the static and dynamic stresses induced in the vehicle components. Meshing of the foldable vehicle is carried using Ansys Workbench. From modal analysis six mode shapes of the foldable vehicle are formulated, corresponding frequencies and deflections are devised. Mesh generator is used to mesh the foldable vehicle. The deflection and frequency magnitudes of foldable vehicle evaluated are in good agreement with the experimental results available in literature for similar materials.

Solar Orbiter observations of solar wind current sheets and their deHoffman-Teller frames

2021 ◽  
Author(s):  
Konrad Steinvall ◽  
Yuri Khotyaintsev ◽  
Giulia Cozzani ◽  
Andris Vaivads ◽  
Christopher Owen ◽  
...  
Keyword(s):  
Solar Wind ◽  
Electric Field ◽  
Wind Velocity ◽  
Solar Wind Velocity ◽  
Field Measurements ◽  
Velocity Measurements ◽  
Current Sheets ◽  
Spacecraft Orbit ◽  
Electric Field Measurements ◽  
Good Agreement

<p>Solar wind current sheets have been extensively studied at 1 AU. The recent advent of Parker Solar Probe and Solar Orbiter (SolO) has enabled us to study these structures at a range of heliocentric distances.</p><p>We present SolO observations of current sheets in the solar wind at heliocentric distances between 0.55 and 0.85 AU, some of which show signatures of ongoing magnetic reconnection. We develop a method to find the deHoffman-Teller frame which minimizes the Y-component (the component tangential to the spacecraft orbit) of the electric field. Using the electric field measurements from RPW and magnetic field measurements from MAG, we use our method to determine the deHoffman-Teller frame of solar wind current sheets. The same method can also be used on the Alfvénic turbulence and structures found in the solar wind to obtain a measure of the solar wind velocity.</p><p>Our preliminary results show a good agreement between our modified deHoffmann-Teller analysis based on the single component E-field, and the conventional deHoffman-Teller analysis based on 3D plasma velocity measurements from PAS. This opens up the possibility to use the RPW and MAG data to obtain an estimate of the solar wind velocity when particle data is unavailable.</p>

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