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.

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.

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).

Experiment Study on Vibration in Milling of Stainless Steel 304 in Time Domain and Frequency Domain

2012 ◽  
Vol 548 ◽  
pp. 406-411
Author(s):  
Yang Shen ◽  
Yong Jie Chen ◽  
Hai Tao Fang ◽  
Jia Pang
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Stainless Steels ◽  
Forced Vibration ◽  
Cutting Tool ◽  
Cutting Speed ◽  
Vibration Acceleration ◽  
Machining Quality ◽  
The Impact ◽  
Acceleration Signals

Vibration is a common phenomenon in cutting process, which is harmful for machining quality and machine tools. This paper focused on the occurrence and characteristics of vibration of the cutting tool and workpiece by changing cutting speed in milling of stainless steels 304. Vibration acceleration signals of both the cutting tool and the workpiece were sampled and analyzed in time domain and frequency domain. Vibration noise and vibration mark were used to judge the occurrence of violent vibration. In the experiments, both self-excited vibration and violent forced vibration were found at different value of cutting speed. Violent forced vibration was easy to be induced owing to interrupted continuous impulsion cutting.The Maximum amplitude of vibration acceleration signals varied with the cutting speed changing. With the cutting speed increased, the probability of violent vibration increased. Bigger amplitude of vibration will not always lead to vibration mark on surface of workpiece, obvious vibration mark only occurred when n=600 r/min and 700 r/min. In order to reduce the impact of violent vibration on machining quality, more attention should also be paid to the static and dynamics characteristics of the cutting tools and workpiece in milling of stainless steels.

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.

Field Measurement and Analysis of Vibration Response in the Metro Shield Tunnel with Straight Joint

2013 ◽  
Vol 838-841 ◽  
pp. 1363-1369
Author(s):  
Ming Yu Li ◽  
Yuan Cheng Guo
Keyword(s):  
Response Time ◽  
Vertical Vibration ◽  
Vibration Response ◽  
Structural Vibration ◽  
Shield Tunnel ◽  
Frequency Range ◽  
Vibration Acceleration ◽  
Steel Spring ◽  
Measurement And Analysis ◽  
Standard Block

Appling the M8 as the monitor objects and choosing the single-round shield tunnel with or without the steel spring floating slab and the DOT shield tunnel with straight joint as the research objects, the vertical vibration response of the track bed and the standard block in different conditions was compared. The peak vibration acceleration of two measuring points and vibration response time of the standard block in the DOT is smaller compared with the DOT and the single-round shield tunnel when a single train is through the monitoring section. Vibration response time and intensity of the DOT structure is increasing with two trains intersection. Compared to the other two shield tunnels, structural vibration response of the single-round shield tunnel is significantly decreased by the isolation effect of steel spring floating slab. For the vibration acceleration of the track bed and the standard block in the three types of shield tunnels, spectrum range is 0Hz~150Hz, and peak acceleration is in the same frequency range, which is 35Hz~70Hz. Peak vibration acceleration of the track bed is greater than that of the standard block.

JOINT INTERPRETATION OF AIRBORNE ELECTROMAGNETIC DATA IN THE TIME DOMAIN AND FREQUENCY DOMAIN

2018 ◽  
Vol 12 (7-8) ◽  
pp. 76-83
Author(s):  
E. V. KARSHAKOV ◽  
J. MOILANEN
Keyword(s):  
Fourier Transform ◽  
Frequency Domain ◽  
Time Domain ◽  
Frequency Interval ◽  
Single Spectrum ◽  
Simultaneous Inversion ◽  
Homogeneous Half Space ◽  
Time Domain Data ◽  
The Time Domain

Тhe advantage of combine processing of frequency domain and time domain data provided by the EQUATOR system is discussed. The heliborne complex has a towed transmitter, and, raised above it on the same cable a towed receiver. The excitation signal contains both pulsed and harmonic components. In fact, there are two independent transmitters operate in the system: one of them is a normal pulsed domain transmitter, with a half-sinusoidal pulse and a small "cut" on the falling edge, and the other one is a classical frequency domain transmitter at several specially selected frequencies. The received signal is first processed to a direct Fourier transform with high Q-factor detection at all significant frequencies. After that, in the spectral region, operations of converting the spectra of two sounding signals to a single spectrum of an ideal transmitter are performed. Than we do an inverse Fourier transform and return to the time domain. The detection of spectral components is done at a frequency band of several Hz, the receiver has the ability to perfectly suppress all sorts of extra-band noise. The detection bandwidth is several dozen times less the frequency interval between the harmonics, it turns out thatto achieve the same measurement quality of ground response without using out-of-band suppression you need several dozen times higher moment of airborne transmitting system. The data obtained from the model of a homogeneous half-space, a two-layered model, and a model of a horizontally layered medium is considered. A time-domain data makes it easier to detect a conductor in a relative insulator at greater depths. The data in the frequency domain gives more detailed information about subsurface. These conclusions are illustrated by the example of processing the survey data of the Republic of Rwanda in 2017. The simultaneous inversion of data in frequency domain and time domain can significantly improve the quality of interpretation.

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