In Situ Experimental Study of Environmental Vibration Induced by CRH on Elevated Railway Station

2013 ◽  
Vol 639-640 ◽  
pp. 930-934
Author(s):  
Quan Min Liu ◽  
Xun Zhang ◽  
Zhi Jun Zhang ◽  
Xiao Zhen Li
Keyword(s):  
Exposure Time ◽  
Longitudinal Vibration ◽  
Vertical Vibration ◽  
Lateral Vibration ◽  
Vibration Acceleration ◽  
Waiting Room ◽  
Box Girder ◽  
Horizontal Vibration ◽  
Acceleration Level ◽  
Environmental Vibration

On the basis of testing the environmental vibration of the different regions of the elevated station, this paper analyzed the experimental data by the time domain, the vibration acceleration level and spectrum, and some meaningful conclusions are obtained. The vertical Z weighted vibration acceleration level of the office and waiting room achieve 80.7dB, 78.8dB, indicating a serious vibration problem about elevated station, and that some more attention should be paid. Office has an equivalent transverse and longitudinal vibration level; the vertical vibration of the office is slightly larger than the waiting room, but the lateral vibration of the office is obviously lower than the waiting room. The exposure time of the vertical vibration is longer than the horizontal vibration in the same location, and a phase difference exists between them. Lateral vibration of the first floor of the station holds a longer exposure time than the box girder, and has lagged far behind in the box girder. The vertical vibration attenuated slower than the horizontal vibration. The high-frequency vibration is attenuated in the propagation from the box girder to the station floor, while the proportion of low-frequency vibration is improved.

scholarly journals The Peculiarities of Remodelling Muscle Tissue of Rats Under the Vibration Influence

PRILOZI ◽  
2019 ◽  
Vol 40 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Nazar M. Kostyshyn ◽  
Liybov P. Kostyshyn ◽  
Marta I. Servetnyk ◽  
Mechyslav R. Grzegotsky
Keyword(s):  
Muscle Tissue ◽  
Vertical Vibration ◽  
Male Rats ◽  
Muscle Fibres ◽  
Transverse Strain ◽  
Vibration Acceleration ◽  
Tissue Remodelling ◽  
Acceleration Level ◽  
Permissible Levels ◽  
Sexually Mature

Abstract Study of the influence of vibration oscillations of different frequency, amplitude and vibration acceleration on the structural and functional state and mechanisms of muscle tissue remodelling. An experimental study was conducted on sexually mature male rats. The rats of the four experimental groups were subjected to vertical vibration oscillations of 15, 25, 50 and 75 Hz, respectively. It has been established that pathological changes in muscle tissue in the form of different variants of damage and remodelling tend to increase, which correlates with the frequency of vibration, amplitude and vibration acceleration level, as in the 2nd group, where the maximum permissible vibration levels did not exceed the established allowable norms, and in other groups of animals, where the permissible levels of total vibration were exceeded. By increasing vibration acceleration for more than 1.25 m/s2 (0.13 g, frequency more than 25 Hz and amplitude of 2 mm), severe damages are observed in the form of alterative changes of muscle fibres with the disappearance of transverse strain, homogenization of sarcoplasm, fragmentation with dissociation fibres on separate beams, partial and subtotal myocytolysis, and necrosis of separate fibres. Inflammation is rapidly increasing with the increase in the frequency of vibration and the level of vibration acceleration for more than 5.0 m/s2 (0.51 g).

Site Test and Analysis of Vibration Attenuation Effect of Steel Spring Floating Slab Track

2014 ◽  
Vol 1065-1069 ◽  
pp. 388-392
Author(s):  
Heng Zhang ◽  
Miao Miao Huo ◽  
Lei Meng ◽  
Xiao Shi An
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Vertical Vibration ◽  
Vibration Acceleration ◽  
Steel Spring ◽  
Slab Track ◽  
Vibration Effect ◽  
Acceleration Level ◽  
Vibration Attenuation ◽  
Site Test

Through site test, the paper conducts site test to vertical vibration accelerations when a train passes through steel rails and tunnel walls at a steel spring floating slab track section and a general track section in the tunnel of Yizhuang Line of Beijing Metro. The paper also conducts comparative analysis of the accelerations in time domain and frequency domain. It is shown in results that the vibration acceleration level of the steel spring floating slab track in time domain is reduced by 22 dB in tunnel walls in comparison with the general track; in the frequency domain, the vibration effect is gradually increased with frequency increase and reaches the optimal effect in medium-high frequency. The maximum vibration attenuation quantity of frequency division reaches up to 40 dB; and the maximum Z weighted vibration acceleration level is reduced by 22 dB.

The Effect of Vibration Condition for Magnesium Dry Gravity Sorting by Vibrating Particulate Bed

2018 ◽  
Vol 941 ◽  
pp. 1535-1539 ◽  
Author(s):  
Shingo Itoh ◽  
Keigo Tsujita ◽  
Taiki Morishige ◽  
Toshihide Takenaka
Keyword(s):  
Recovery Rate ◽  
Vertical Vibration ◽  
Mg Alloys ◽  
Vibration Acceleration ◽  
High Recovery ◽  
Horizontal Movement ◽  
Horizontal Vibration ◽  
High Acceleration ◽  
The Relationship ◽  
Vibrational Condition

Recycling Mg alloys has been demanded as the demand of Mg alloys has been increased. It is difficult to separate Mg with Al because the properties are similar except for the density. In this study, gravity sorting by vibrating particulate bed ajusted the density to intermediate between Mg and Al was applied for Mg separation with Al. The relationship the vibrating condition and the sorting accuracy was investigated by applying different vibration acceleration and by applying the vertical and horizontal vibration. Turbulent flow was observed and the recovery rate was improved when vertical vibration with high acceleration was applied to the bed. Higher recovery rate was achieved when horizontal vibration was applied to the bed. This result suggested that the horizontal movement of particle affected the behavior of sorting materials and high recovery ratio was achieved by optimizing vibrational condition such as vibration acceleration and the direction of vibration.

Comparative results of evaluating the smoothness of automatic transmission gear shifting during car operation

2020 ◽  
Keyword(s):  
Longitudinal Vibration ◽  
Automatic Transmission ◽  
Quality Criteria ◽  
Technical Condition ◽  
Vibration Velocity ◽  
Vibration Acceleration ◽  
Passenger Cars ◽  
Shift Quality ◽  
Vibroacoustic Diagnostics ◽  
Comparative Results

The authors have studied the process of gear shifting, smoothness of it and peculiarities of automatic gearbox functioning of during car operation. The article describes the urgency of the problem of jerks and vibrations when changing gears. When assessing the smoothness of gear shifting, the method of technical state vibroacoustic diagnostics is applied. The method is based on the recorded parameters of vibration velocity, vibration acceleration, vibration movement with their further conversion (fast Fourier transform) into a spectralsignal. The procedure of longitudinal vibration acceleration measurements on cars in operation is described. A comparative analysis of the smoothness of gear shifting in an automatic transmission was carried out using the example of modern passenger cars. Keywords car; car operation; automatic gearbox; technical condition; gearbox malfunction; smoothness; jerks; jolts; gear shift quality criteria; vibration acceleration

scholarly journals Ride Comfort Control System Considering Physiological and Psychological Characteristics: Effect of Masking on Vertical Vibration on Passengers

Actuators ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 42 ◽  
Author(s):  
Keigo Ikeda ◽  
Ayato Endo ◽  
Ryosuke Minowa ◽  
Takayoshi Narita ◽  
Hideaki Kato
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Ride Comfort ◽  
Control Method ◽  
Vertical Vibration ◽  
Psychological Characteristics ◽  
Psychological State ◽  
Vibration Acceleration ◽  
Seat Suspension ◽  
Vibration Stress

Active seat suspension has been proposed to improve ride comfort for ultra-compact mobility. Regarding the ride comfort of passengers due to vertical vibration, the authors have confirmed from biometry measurements that reduction of the vibration acceleration does not always produce the best ride comfort for passengers. Therefore, heart rate variability that can quantitatively reflect stress is measured in real time, and a control method was proposed that feeds back to active suspension and confirms its effectiveness by fundamental verification. In this paper, we will confirm the influence of the vibration stress on the psychological state of the occupant by the masking method.

A comparative study of the vibration characteristics of railway vehicle axlebox bearings with inner/outer race faults

2020 ◽  
pp. 095440972097908
Author(s):  
Jinhai Wang ◽  
Jianwei Yang ◽  
Yongliang Bai ◽  
Yue Zhao ◽  
Yuping He ◽  
...  
Keyword(s):  
Longitudinal Vibration ◽  
Research Work ◽  
Vertical Vibration ◽  
Fault Identification ◽  
Railway Vehicle ◽  
Outer Race ◽  
Longitudinal Dynamic ◽  
Healthy State ◽  
Inner Race ◽  
Peak Value

Increasing service time makes the axlebox bearing of railway vehicle vulnerable to develop a fault in inner or outer races, which can cause some serious adverse effects on a railway vehicle’s safe operation. To tackle this problem, we established a railway vehicle vertical-longitudinal dynamic model with inner/outer races faults of axlebox bearing and validated it by experimental data. We utilized the time-synchronous average (TSA) technology to filter the raw signals and studied their vibration features. The results show that the longitudinal vibration features are more sensitive for inner race fault identification, while the vertical vibration features are more suitable for outer race fault identification. For inner race fault identification, the indicator peak-to-peak value (PPV) that increases 1056% relative to the healthy state at the most severe fault performs the best sensitivity. For outer race fault identification, the indicator skewness value (SV) that increases 518% relative to the healthy state at the most severe fault exhibits the best performance. The research work can provide meaningful guidance for accurate diagnosis of axlebox bearing faults of railway vehicles.

scholarly journals Experimental investigation on the correlation of pressure pulsation and vibration of axial flow pump

2019 ◽  
Vol 11 (11) ◽  
pp. 168781401988947
Author(s):  
Xiaohui Duan ◽  
Fangping Tang ◽  
Wenyong Duan ◽  
Wei Zhou ◽  
Lijian Shi
Keyword(s):  
Pressure Pulsation ◽  
Axial Flow ◽  
Domain Analysis ◽  
Vertical Vibration ◽  
High Flow ◽  
Design Flow ◽  
Flow Rates ◽  
Horizontal Vibration ◽  
Axial Flow Pump ◽  
Flow Pump

Pressure and vibration displacement value are relatively measured by 14 pressure sensors and 2 vibration sensors distributing inside the tank-type model axial flow pump device under different flow rates. By comparison, it is found that the pressure pulsation on the inlet of the impeller is the main cause of hydraulic induced vibration of the pump device, and it is found to have similar amplitude trend with the vertical vibration as the flow rates increases and large correlation coefficient with the horizontal vibration under high flow rates through time-domain analysis. By frequency-domain analysis, it is found that the main frequency of pressure pulsation is three multiplies of the shaft frequency, but it is one multiplies of vertical vibration, and it changes from one multiplies to three multiplies of horizontal vibration. Combining with the analysis of phase-flow rates characteristics of both pressure pulsation and vibration, it is concluded that, for the horizontal vibration, the frequency ingredient of one multiplies ranging from low to high flow rates and three multiplies removing from unstable and high flow rates zone are possibly induced by pressure pulsation on the inlet of impeller, while for the vertical vibration, the frequency ingredient of one multiplies under design flow rates and high flow rates are possibly induced by pressure pulsation on the inlet of impeller. Both the horizontal and vertical vibrations with frequency of two multiplies have little relationship with the pressure pulsation on the inlet of impeller.

Influence Analysis of Cell Plate Length to Slab Track Vertical Dynamic Response

2014 ◽  
Vol 505-506 ◽  
pp. 58-63
Author(s):  
Xiao Chuan Ma ◽  
Wei Luo ◽  
Ping Wang ◽  
Bao Ru Guo
Keyword(s):  
Dynamic Response ◽  
Base Plate ◽  
Shell Element ◽  
Cell Plate ◽  
Vertical Vibration ◽  
Vibration Acceleration ◽  
Vibration Displacement ◽  
Coupling Vibration ◽  
Slab Track ◽  
Plate Length

A vehicle-track-subgrade coupling vibration system model was proposed to analysis the influence of cell plate length to slab track vertical dynamic response. The model was built with finite element method, rail was modeled as space beam element, both track plate and base plate were modeled as shell element, the vertical connections between rail, slab and subgrade were modeled as spring-damper element. The results show that with the cell plate length increases, the vertical vibration displacement of rail, track plate and base plate have decreasing tendency; the vertical vibration acceleration of rail has increasing tendency; the vertical vibration acceleration of track plate and base plate have decreasing tendency.

Decrements in Tracking and Visual Performance during Vibration

1973 ◽  
Vol 15 (4) ◽  
pp. 379-393 ◽  
Author(s):  
Allan M. Collins
Keyword(s):  
Visual Acuity ◽  
Literature Review ◽  
Human Performance ◽  
Vertical Vibration ◽  
Experimental Results ◽  
Visual Performance ◽  
Lateral Vibration ◽  
Do So

This literature review specifies the decrements in human performance on tracking and visual acuity tasks during vibration in terms of frequency, acceleration, and direction of vibration. For z-axis (vertical) vibration, which has been studied most extensively, it has been possible to develop tentative equal-decrement curves in terms of frequency and acceleration. For x-axis (longitudinal) and y-axis (lateral) vibration, there are not enough data to do so. The effects of other variables are discussed briefly, and an hypothesis is offered for translating experimental results into predictions of performance decrements for workers in vibration environments.

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.

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