scholarly journals Field Testing and Analysis of Embankment Vibrations Induced by Heavy Haul Trains

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Peng Li ◽  
Xianzhang Ling ◽  
Feng Zhang ◽  
Yan Li ◽  
Yingying Zhao
Keyword(s):  
Low Frequency ◽  
Ground Vibration ◽  
Field Testing ◽  
Dominant Frequency ◽  
Test Results ◽  
Heavy Haul ◽  
Frequency Components ◽  
Embankment Height ◽  
Heavy Haul Trains ◽  
The Relationship

This paper presents a field testing of track and ground-borne vibration generated by heavy haul trains. The test sites consisted of three embankments with height of 6.6, 8.1, and 11.9, respectively. The acceleration signals of the rail, sleeper, and embankment surface were recorded, and then the propagation characteristics of ground vibration with distance to track center were contrastively analyzed. The test results show that horizontal vibration was dominant for locations near the track but decreased rapidly and became comparable with the vertical levels as the distance from track center increases. The quasi-static excitation dominated the sleeper response, and the dominant frequency range was found in the low-frequency zone corresponding to the fundamental axle passage frequency. For embankment surface, another pronounced dominant frequency zone was observed between 30 and 80 Hz, which was attributed to the dynamic excitation. Moreover, these higher frequency components were more promptly attenuated than low-frequency ones. The reason that vibration levels generated by locomotive were greater than wagon was attributed to the different bogie suspension mode. The relationship between normalized PPV and distance from track center in doubly logarithmic scales can be expressed with exponential function, and the vibration attenuation rates were restrained with increasing the embankment height.

scholarly journals Development of an on-site system for measuring the low-frequency noise and complainant’s responses

2018 ◽  
Vol 37 (2) ◽  
pp. 373-384
Author(s):  
Hiroshi Sato ◽  
Jongkwan Ryu ◽  
Kenji Kurakata
Keyword(s):  
Time Trends ◽  
Sound Pressure ◽  
Low Frequency ◽  
Dominant Frequency ◽  
Pressure Level ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Measurement Results ◽  
Frequency Components ◽  
The Relationship

An on-site system for measuring low-frequency noise and complainant's responses to the low-frequency noise was developed to confirm whether the complainant suffer from the environmental noise with low-frequency components. The system suggests several methods to find the dominant frequency and major sound pressure level spectrum of the noise causing annoyance. This method can also yield a quantified relationship (correlation coefficient and percentage of response to the noise) between physical noise properties and the complainant’s responses. The advantage of this system is that it can easily find the relationship between the complainant’s response to the acoustic event of the houses and the physical characteristics of the low-frequency noise, such as the time trends and frequency characteristics. This paper describes the developed system and provides an example of the measurement results.

Vibration Energy Harvesting to Power Ultrasonic Sensors in Heavy Haul Railway Cars

2018 ◽  
Author(s):  
Auteliano A. Santos ◽  
Matheus V. Lopes ◽  
Vanessa Gonçalves ◽  
Jony J. Eckert ◽  
Thiago S. Martins
Keyword(s):  
Economic Value ◽  
Low Frequency ◽  
Electrical Energy ◽  
Vibration Energy ◽  
Vibration Energy Harvesting ◽  
Vibration Energy Harvester ◽  
Important Indicator ◽  
Suitable Alternative ◽  
Heavy Haul ◽  
Heavy Haul Trains

Long heavy-haul trains are now a reality, especially for ore transportation. In some railways, compositions of up to 330 wagons are in service, requiring several locomotives. Trains like that travel long distances, sometimes through cities or in uninhabited regions. They are driven by just one driver which must keep the whole train working safely on the track. The wagons don’t have any source of electrical energy to power sensors and to transmit their signals to the locomotive; nor wireless communication. In fact, in some of these railways, there is no internet along with the track out of the cities. One important indicator of the safety of the train is the force between the wagons during the trip, through the shunting. Using strain gauges to measure these forces is a possible solution and ultrasonic stress sensors (UST) is a suitable alternative. UST with Lcr waves requires a low amount of energy and can be employed in rusty and dirty places. However, they also need an energy source. Wind and solar solutions are not always adequate because, unfortunately, there are places where these components have economic value and they can be stolen. A possible source of energy to power the USTs could be the Vibration Energy Harvester (VEH). These simple and not expensive systems can be built in small packs, giving the energy to measure the forces and transmit the data to the locomotive or designated sites along the track. This work aims to evaluate the possibility of using VEH to power USTs to measure the forces between the wagons during the journey. Knowing that the oscillation in the shunting has a very low frequency, the work intent to optimize a multi-beam VEH to be able to capture the highest amount of energy possible, in a very small arrangement, using genetic algorithm. The result shows that VEH is an adequate alternative to power autonomous UST sensors.

Experimental investigation on the characteristics of the dynamic rail pad force and its stress distribution in the time and frequency domain

2019 ◽  
Vol 234 (2) ◽  
pp. 201-213 ◽  
Author(s):  
Xu Zhang ◽  
Chunfa Zhao ◽  
Xiaobo Ren ◽  
Yang Feng ◽  
Can Shi ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Frequency Domain ◽  
Maximum Stress ◽  
Field Tests ◽  
Service Condition ◽  
Field Testing ◽  
Dominant Frequency ◽  
Test Results ◽  
Parabolic Shape ◽  
Dominant Frequencies

The rail pad force and its stress distribution have critical influences on the performance and fatigue life of the rail, fasteners, and sleepers. The characteristics of the rail pad force and its stress distribution in the time and frequency domain obtained from field tests carried out using matrix-based tactile surface sensor are presented in this paper. The field testing involved rail pads under various axle-loads of running trains at different speeds. The influences that the train axle-load, the operational speed, and the rail pad stiffness have on the rail pad force and its stress distribution are analyzed. The test results indicate that the rail pad stiffness has a remarkable influence on the amplitude of the rail pad force but has little influence on its dominant frequencies. The first dominant frequency of the rail pad force is quite close to the passing frequency of the vehicle length. The stress distribution on the rail pad has a parabolic shape along the longitudinal and the lateral directions with the large stress appearing near the center of the rail pad, and is remarkably affected by the service condition of the rail pad. The maximum stress is about 2.5 to 3 times of the average stress, which is significantly greater than the nominal stress resulting from the assumption of uniform stress distribution.

In Situ Measurement of Ground Vibration Induced by Inter-City Express Train

2012 ◽  
Vol 204-208 ◽  
pp. 502-507 ◽  
Author(s):  
Quan Min Liu ◽  
Xun Zhang ◽  
Zhi Jun Zhang ◽  
Xiao Zhen Li
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Ground Vibration ◽  
Vertical Vibration ◽  
Test Results ◽  
Low Frequency Vibration ◽  
Express Train ◽  
Environmental Vibration ◽  
Logarithmic Relationship

On the basis of the measured ground borne vibration of some inter-city express railway viaduct, test results analysis shows that: the test environmental vibration is under the limit set by standard of environmental vibration in urban area; whether transverse or vertical vibration, a rapid attenuation of the peak acceleration with the distance to the up-track center is observed, however the vibration at 7.5m appears to be amplified; the ground vibration with the distance conforms to a logarithmic relationship; the horizontal ground vibration at 7.5m caused by the elevated rail transit is larger 3.6cm/s2 than the vertical vibration; low-frequency vibration transfers farther than high frequency vibration; the eccentric effect of two-track viaduct is obvious.

Feature Analysis of Mechanical Fault Signals Based on the Wavelet Transform Technique

2010 ◽  
Vol 139-141 ◽  
pp. 2502-2505
Author(s):  
Bing Cheng Wang ◽  
Zhao Hui Ren
Keyword(s):  
High Frequency ◽  
Amplitude Spectrum ◽  
Low Frequency ◽  
Feature Analysis ◽  
Oil Whip ◽  
Frequency Components ◽  
Quantitative Manner ◽  
Beat Phenomenon ◽  
The Impact ◽  
The Relationship

Simulated four different fault signals in the lab, the authors then used wavelet scalogram and amplitude spectrum to make analysis on the above four fault signals and abstract each spectrum characteristics. Wavelet scalogram was able to extract the characteristic’s frequency, show the impact components caused by rub-impact, show the beat phenomenon caused by oil whip and show the irreducible high frequency components as well as the complex low-frequency components. Amplitude spectrum was able to show the energy size distribution at various frequency bands and able to analyze and calculate the relationship between various frequency components. Thus they express the relationship between various frequency banks from a quantitative manner. Therefore, combining the wavelet scalogram and amplitude spectrum when making analysis, as they complement and verify each other, it will enhance the reliability when extract and analyze the characteristics of fault signal.

scholarly journals The Relationship Between Cerebral Blood Flow and the EEG in Normals

1980 ◽  
Vol 7 (3) ◽  
pp. 195-198 ◽  
Author(s):  
Devidas Menon ◽  
Zoltan Koles ◽  
Allen Dobbs
Keyword(s):  
Blood Flow ◽  
Low Frequency ◽  
Weight Percent ◽  
Initial Slope ◽  
Inhalation Technique ◽  
Frequency Components ◽  
Flow Through ◽  
Gamma Rhythms ◽  
The Subject ◽  
The Relationship

SUMMARY:Using the Xel33 inhalation technique, measurements of the blood flow to the left and right parietal and temporal regions of the cerebrum were obtained in 5 healthy individuals while simultaneously recording their EEGs. Up to 3 measurements were obtained from each of the subjects the first while they were mentally at rest and the others while they were engaged in prescribed forms of mental activity. Relationships between the measured blood flow through grey matter, initial slope index, relative grey weight, percent grey flow and power in the delta, delta-theta, alpha, beta and gamma rhythms of the EEG were examined. The results showed that for the subject group as a whole there was a strong correlation between the power present in the low frequency components of EEG and the grey flow and relative grey weight parameters of blood flow. On an individual basis, the observed relationships were highly variable particularly at high flow rates and at low relative grey weights, but became much more definitive at low flows and high weights. The results as they relate to previous work of this kind are discussed.

Correlations between Gun-Barrels Temperature Rising and Shooting Specifications

2015 ◽  
Vol 775 ◽  
pp. 115-118 ◽  
Author(s):  
Yong Hai Shan ◽  
Zheng Gang Nie ◽  
Shi Qi Shan ◽  
Li Dong Tan
Keyword(s):  
Temperature Field ◽  
Temperature Variation ◽  
Field Testing ◽  
Test Results ◽  
Experimental Basis ◽  
Dynamic Tests ◽  
Life Test ◽  
The Relationship ◽  
Temperature Dynamic

Gun barrels life closely related to the gun barrels temperature variation. On the basis of analyzing gun barrels temperature various characteristics and rules during machine-guns firing, according to gun barrels life factors and their impact on gun barrels life, test programs under different shooting combined conditions and gun barrels temperature field testing programs are designed. Through the gun barrels temperature dynamic tests and test results during shooting, analyze and put forward the relationship between gun barrels temperature rising and firing specification. Which provides the experimental basis for choice of machine-gun barrels life stresses and analysis of the life-ended rules.

scholarly journals Spectra of Low-Frequency Ground Vibrations Generated by High-Speed Trains on Layered Ground

1997 ◽  
Vol 16 (4) ◽  
pp. 257-270 ◽  
Author(s):  
V.V. Krylov
Keyword(s):  
High Speed ◽  
Low Frequency ◽  
Ground Vibration ◽  
Ground Vibrations ◽  
Frequency Spectra ◽  
Low Frequencies ◽  
High Speed Trains ◽  
Frequency Components ◽  
Noticeable Reduction ◽  
Layered Ground

Increase in speeds of modern railway trains is usually accompanied by higher levels of generated ground vibrations. In the author's earlier paper [V.V. Krylov, Applied Acoustics, 44, 149–164 (1995)], it has been shown that especially large increase in vibration level may occur if train speeds v exceed the velocity of Rayleigh surface waves in the ground cR., i.e., v > cR. Such a situation might arise, for example, with French TGV trains for which speeds over 515 km/h have been achieved. The present paper investigates the effect of geological layered structure of the ground on ground vibrations generated by high-speed trains. It is shown that, since Rayleigh wave velocities in layered ground are dispersive and normally increase at lower frequencies associated with deeper penetration of surface wave energy into the ground, the trans-Rayleigh condition v > cR may not hold at very low frequencies. This will cause a noticeable reduction in low-frequency components of generated ground vibration spectra. Theoretical results are illustrated by numerically calculated frequency spectra of ground vibrations generated by single axle loads travelling at different speeds and by TGV or Eurostar high-speed trains.

Experimental assessment of the dynamic performance of slave control locomotive couplers in 20,000-tonne heavy-haul trains

2021 ◽  
pp. 095440972199361
Author(s):  
Xin Ge ◽  
Liang Ling ◽  
Zaigang Chen ◽  
Jie Zhang ◽  
Kaiyun Wang ◽  
...  
Keyword(s):  
Dynamic Performance ◽  
Test Method ◽  
Test Results ◽  
Release Process ◽  
Dynamic Motion ◽  
Operation Conditions ◽  
Heavy Haul ◽  
Heavy Haul Trains ◽  
Yaw Angle ◽  
Field Test Method

Coupler jack-knifing and derailment of slave control locomotives in 20,000-tonne heavy-haul trains usually occur due to the combinations of large in-train forces with poor track conditions. This paper presents an experimental investigation on the dynamic performance of slave control locomotive couplers in 20,000-tonne heavy-haul trains. A field test method for measuring and monitoring the dynamic behavior of heavy-haul locomotive couplers is proposed. The on-track tests involved coupler forces, coupler yaw angles, and coupler dynamic motion monitoring of the test locomotive in the whole traveling process. The dynamic process of coupler jack-knifing is exhibited, and the distribution characteristics of the coupler forces and yaw angles are investigated. The test results indicate that the front and rear couplers of the slave locomotive group respectively suffer the largest draw (tensile) and buffing (compressive) forces, and the maximum yaw angle appears at the middle coupler between the slave locomotives. The maximum draw and buffing forces attain 1551 kN and 2067 kN, respectively. The maximum absolute yaw angle is about 13 degrees. During the cycle braking operation conditions, the intense buffing forces and the excessive coupler yaw angles are more likely to appear in the release process. The coupler instability generally occurs under train run in buffing forces. Moreover, the coupler status, the track conditions as well as the duration of buffing forces are also supposed to have an important effect on the coupler stability of slave control locomotives.

Galloping Characteristics of Conductor Accreted with Crescent-Shaped Ice

2012 ◽  
Vol 226-228 ◽  
pp. 158-161 ◽  
Author(s):  
Hui Xue Dang ◽  
Feng Li Yang ◽  
Xin Min Li ◽  
Jing Bo Yang
Keyword(s):  
High Frequency ◽  
Software Package ◽  
Free Stream ◽  
Low Frequency ◽  
Frequency Component ◽  
High Frequency Component ◽  
Span Length ◽  
Test Results ◽  
Frequency Components ◽  
Commercial Software Package

Accounting for the disastrous phenomena of ice-accreted conductor galloping, wind tunnel tests of LGJ630/45 conductor accreted with crescent-shaped ice are conducted. Based on the test results, conductor galloping is simulated by employing the PCL language of ANSYS commercial software package and then the influences of span lengths as well as free-stream speeds on galloping characteristics are studied. The results indicate that, conductor galloping consists several different frequency components. With the increase of span length, galloping energy moves from low-frequency component to its high-frequency counterpart, and finally high-frequency component dominates the galloping phenomenon. And with the movement of energy, galloping traces transforms from ellipse to that similar to a butterfly. With the increase of span length, the maximum cable tension first increases, next decreases sharply, and then increases again.

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