scholarly journals Study on the Transmission and Evolution Characteristics of Vibration Wave from Vibratory Roller to Filling Materials Based on the Field Test

2020 ◽  
Vol 10 (6) ◽  
pp. 2008
Author(s):  
Changwei Yang ◽  
Liang Zhang ◽  
Yixuan Han ◽  
Degou Cai ◽  
Shaowei Wei
Keyword(s):  
Frequency Domain ◽  
Fundamental Wave ◽  
Primary Wave ◽  
Compaction Process ◽  
Vibration Acceleration ◽  
Intelligent Compaction ◽  
Filling Materials ◽  
Evolution Characteristics ◽  
Attenuation Rate ◽  
Vibration Wave

Compaction quality of railroad subgrade relates directly to the stability and safety of train operation, and the core problem of the Intelligent Compaction of railroads is the transmission and evolution characteristics of vibration wave. Aiming at the shortages in exploring the transmission and evolution characteristics of the vibration signal, the typical subgrade compaction project of Jingxiong Intercity Railway Gu’an Station was selected to carry out the field prototypes tests, and the dynamic response from the vibratory roller to filling materials was monitored in the whole compaction process, and some efficient field tests data will be obtained. Based on this, the transmission and evolution characteristics of the vibration wave from the vibratory roller to filling materials in the compaction process are studied from the time domain, frequency domain, jointed time–frequency domain and energy domain by using one new signal analysis technology—Hilbert–Huang Transform. Some conclusions are shown as follows: first, the vibration acceleration peak gradually decreases with the increase of buried depth, and when the buried depth reaches 1.8 m, the vibration acceleration peak is closed to zero. At the same time, when the vibration wave propagates from the wheel to the surface of filling, the attenuation rate of acceleration gradually increases with the increase of rolling compaction times, while the attenuation rate of other layers in different buried depths gradually decreases. Second, the vibration wave contains fundamental wave and multiple harmonics, and the dominant frequency of the fundamental wave is nearly 21 Hz. With the increase of buried depth, the amplitude of fundamental, primary, secondary, until fifth harmonics decreases exponentially and the concrete functional relationship among different amplitudes of harmonics can be summarized as y = Ae−BX. Third, the vibration energy focuses on the fundamental wave and primary wave, which can increase with the increase of rolling compaction times, and when the rolling compaction time reaches five, their energy reaches maximum. However, when the filling reaches a dense situation, the energy of the primary wave gradually decreases. Therefore, the maximum rolling compaction time is five in the practical engineering applications, which will be helpful for optimizing the compaction quality control models and providing some support for the development of the Intelligent Compaction theory of railway subgrade.

Model Test Study on Vibration Transferring of Dynamic Compaction and the Measures of Reducing Vibration

2011 ◽  
Vol 368-373 ◽  
pp. 3121-3126 ◽  
Author(s):  
Qing Juan Meng ◽  
Wei Hua Ma ◽  
Jing Sheng Qiao
Keyword(s):  
Model Test ◽  
Vibration Isolation ◽  
Influence Factors ◽  
Dynamic Compaction ◽  
Vibration Acceleration ◽  
Horizontal Vibration ◽  
Filling Materials ◽  
Surrounding Environment ◽  
Test Study ◽  
Compaction Method

Dynamic compaction method was widely used in various engineering foundation reinforcement, the research of influence to surrounding environment from dynamic compaction and the measures of reducing vibration was not complete. In this paper, the decay laws of dynamic compaction vibration acceleration in horizontal direction was got through the model test, the attenuation formula of horizontal vibration acceleration was fitted, which provides theory basis for determining the influence scope of dynamic compaction; And the depth and filling materials two influence factors of vibration isolation ditch were researched by model tests, which provide important basises for the application of vibration isolation ditch.

scholarly journals Potential of Optical Frequency Domain Imaging for Differentiation Between Early and Advanced Coronary Atherosclerosis

2021 ◽  
Author(s):  
Takahiro Imanaka ◽  
Kenichi Fujii ◽  
Takamasa Tanaka ◽  
Koji Yanaka ◽  
Toshio Kimura ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Cross Sections ◽  
Early Stage ◽  
Optical Frequency ◽  
Signal Attenuation ◽  
Optical Frequency Domain Imaging ◽  
Poor Region ◽  
Attenuation Rate ◽  
Significant Difference ◽  
Histological Images

Abstract Purpose Optical frequency domain imaging (OFDI) is widely used to characterize lipidic-atherosclerotic plaques, shown as signal-poor regions with diffuse borders, in clinical setting. Given that lipid components are common to both fibroatheroma (FA) and pathological intimal thickening (PIT), it is unclear whether OFDI can be used to accurately distinguish between FA and PIT. This study evaluated the differences in OFDI findings between FA and PIT in comparison with histopathology. Methods A total of 631 histological cross-sections from 14 autopsy hearts were analyzed for the comparison between OFDI and histological images. Of those, 190 (30%) sections were diagnosed with PIT and 120 (19%) with FA. All OFDI images were matched with histology and the OFDI signal attenuation rate was calculated from an exponential. The lipid length was measured longitudinally, and the lipid arc was measured with a protractor centered in the center of the lumen. Results There was no significant difference in the OFDI signal attenuation rate between FA and PIT (3.09 ± 1.04 versus 2.79 ± 1.20, p = 0.13). However, the lipid length was significantly longer and the maximum lipid arc was significantly larger in FA than in PIT (7.5 [4.3–10.3] mm versus 4.3 [2.7–5.8] mm, p < 0.0001, and 125 [101–174]° versus 96 [74–131]°, p < 0.0001, respectively). Conclusions OFDI may be capable of discriminating advanced lipid plaques from early stage atherosclerosis based on the longitudinal and circumferential extent of signal-poor region.

scholarly journals Experimental Investigation of the Effects of the Gangue Particle Size on the Evolution Rules of Key Seepage Parameters

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Lihua Wang ◽  
Jixiong Zhang ◽  
Yongqi Wei ◽  
Cunli Zhu ◽  
Gaolei Zhu
Keyword(s):  
Numerical Simulation ◽  
Theoretical Foundation ◽  
Solid Wastes ◽  
Practical Significance ◽  
Ecological Environment ◽  
Hydraulic Pressure ◽  
Filling Materials ◽  
Evolution Characteristics ◽  
Simulation Results ◽  
Seepage Characteristics

In order to deal with solid wastes and protect the fragile ecological environment on the ground, using gangues as the filling materials in the underground goaf can not only achieve favorable waste disposal but also alleviate surface subsidence and protect surface buildings and the ecological environment, with great practical significance and application prospects. During the water seepage process, the evolution rules of inner seepage channels in the bulk filling materials are the theoretical foundation for the realization of water-preserved mining. In order to gain clear knowledge of the seepage characteristics of the bulk filling gangues with different sizes, the evolution rules of some seepage parameters mainly including the displacement, the porosity, and the permeability of gangues and hydraulic pressure were analyzed via COMSOL numerical simulation. The evolution rules of the seepage characteristics of the bulk filling materials with different sizes were revealed by combining the present experimental and numerical results. Moreover, the present seepage experiment was proved to be reliable by comparing with numerical simulation results. This work can provide theoretical foundation for investigating the evolution characteristics of inner seepage paths in the bulk filling materials and selecting appropriate bulk filling materials under different stress and seepage environments.

The Study of Planar Five-Bar Parallel Robot Dynamic Characteristics

2012 ◽  
Vol 468-471 ◽  
pp. 954-958
Author(s):  
Shang Yue Chen ◽  
Hong Bing Xin ◽  
Han Ning Mo ◽  
Mei Yu Chen ◽  
Dong Yang Zhao
Keyword(s):  
Experimental Data ◽  
Control System ◽  
Frequency Domain ◽  
Dynamic Characteristics ◽  
Parallel Robot ◽  
Robot Dynamics ◽  
Main Function ◽  
Vibration Acceleration ◽  
Experimental Purpose ◽  
End Effectors

By introducing the experimental purpose, instruments and the main function of the planar five-bar parallel robot dynamics, this paper concluded the principle diagram of control system of the planar five-bar parallel robot. And the method and process of the experiment was detailed description. Through the analysis of vibration acceleration curve and frequency domain curve, which were obtained by the experimental data of the planar five-bar parallel robot end-effectors, the characteristics of time and frequency domain of the planar five-bar parallel robot were clearly shown.

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.

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.

scholarly journals Research on the Impediment to Vibration Wave Propagation of Pipe from a vibration isolation mass

2019 ◽  
Vol 288 ◽  
pp. 01002
Author(s):  
Gong Yufeng ◽  
Peng Weicai ◽  
Zhang Junjie ◽  
Liu Zhizhong
Keyword(s):  
Wave Propagation ◽  
Numerical Analysis ◽  
Frequency Domain ◽  
High Frequency ◽  
Vibration Isolation ◽  
Rotational Inertia ◽  
Analysis Method ◽  
Damping Effect ◽  
Vibration Wave ◽  
Pipe Vibration

In order to control the pipe vibration, the performance of flexible connection with vibration isolation mass in impeding vibration wave propagation is studied. Based on the principle of impedance mismatching and numerical analysis method, the influences of vibration isolation mass and rotational inertia on the vibration wave propagation in pipe were discussed. The results show that the isolation mass is good at reducing the vibration of wave transmission in intermediate and high frequency domain. Meanwhile, The larger rotational inertia of the isolation mass, the better the damping effect. A useful reference was provided for the application of flexible connection to the vibration isolation and noise reduction of ship pipe.

The Characteristics of Low Frequency on Detecting Method via Strain Gages

2012 ◽  
Vol 482-484 ◽  
pp. 1161-1164
Author(s):  
Xiao Jun Li ◽  
Wen Ming Zhu ◽  
Yu Guo Wang ◽  
Yu Zhang
Keyword(s):  
Frequency Domain ◽  
High Frequency ◽  
Low Frequency ◽  
Sensor System ◽  
Strain Gages ◽  
Acceleration Sensor ◽  
Vibration Acceleration ◽  
Frequency Information ◽  
The One ◽  
Detecting Method

In order to find out the feasibility to obtain dynamics peculiarity in high frequency domain, the dynamic peculiarity on detecting method with strain gages is researched. By modeling and analyzing qualitatively, the characteristics of low frequency are indicated for strain gages sensor system. Comparing with the test signal difference between vibration acceleration sensor and strain gages sensor system at the three domain which are time, amplitude and frequency, the characteristics of low frequency are proved for the one. Therefore while detecting the high frequency dynamic signal with strain gages sensor system, the high frequency information is attenuated, the mostly spectrum information is lost.

scholarly journals Study on Intelligent Compaction-Equipment Logistics Scheduling and Propagation Characteristics of Vibration Wave in Nonlinear Systems with Multistability Based on Field Test

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yixuan Han ◽  
Changwei Yang ◽  
Degou Cai ◽  
Hongye Yan ◽  
Hailing Zeng
Keyword(s):  
Nonlinear Systems ◽  
Vibration Energy ◽  
Filling Material ◽  
Construction Technology ◽  
Propagation Characteristics ◽  
Peak Acceleration ◽  
Energy Propagation ◽  
Intelligent Compaction ◽  
Vibration Wave ◽  
Construction Efficiency

The equipment scheduling and propagation characteristics of vibration wave from vibratory roller ⟶ filling material nonlinear systems with multistability are the core problems of subgrade intelligent construction technology, and the logistics scheduling of the equipment is directly related to the construction efficiency. Aiming at the shortages, one typical subgrade located at the Gu’an station of Beijing-Xiong’an city railway is selected to research and finish the field tests; some findings are shown as follows: first, some valuable suggestions about the logistics scheduling of intelligent equipment are proposed, which can break the barriers between the organizations and improve construction efficiency; second, when the vibration wave propagates from the vibratory roller ⟶ surface of filling material ⟶ different buried depths of filling material, the peak acceleration of vibration wave gradually decreases and is hyperbolic distribution approximately. At the same time, the sensitive of attenuation is shown as follows: Z<X ≈ Y, and the critical depth of vibration energy propagation is about 1.0 m. At the same time, the peak acceleration of vibration wave at the interface of different filling material layers exists in steps and is “side clock” distribution approximately with the increase in buried depth. Third, in the propagation process, with the increase in buried depth, the amplitude of fundamental, primary, secondary, until fifth harmonics decreases exponentially (R2>0.9), and the concrete functional relationship among different amplitudes of harmonics can be summarized as y = Ae−BX; fourth, the vibration energy is mainly concentrated near 10–30 Hz in the vibratory roller, but when the vibration wave propagates from vibratory roller⟶filling material, the vibration energy gradually decreases with the increase in depth, and the marginal spectrum gradually changes from one peak to two peaks, that is, 30–50 Hz and 50–100 Hz; fifth, the vibration energy in the vibrational wheel is distributed averagely in the compaction process, and the effective compaction time is two seconds, which will be helpful for revealing the propagation characteristics of vibration wave, optimizing the compaction quality control models and providing some support for the development of intelligent compaction theory of railway subgrade.

Experimental Study on Controlling Rail Corrugation by Tuning Rail Damper

2014 ◽  
Vol 587-589 ◽  
pp. 1002-1006
Author(s):  
Heng Zhang ◽  
Liang Jiang ◽  
Yu Jie Li ◽  
Lei Meng ◽  
Xiao Shi An
Keyword(s):  
Experimental Study ◽  
Decay Rate ◽  
Vertical Vibration ◽  
Vibration Acceleration ◽  
Rail Corrugation ◽  
Before And After ◽  
Speed Up ◽  
Vibration Wave ◽  
And Control ◽  
Rail Damper

At a serious rail corrugation line along Beijing metro Yi-zhuang line, one experiment of controlling rail corrugation has done. Based on the test and analysis of rail vibration decay rate, rail surface roughness and vibration acceleration on the rail and track bed before and after install TRD, it is concluded that install TRD on rail waist could improve rail damping, enhance rail vibration decay rate, speed up vibration wave propagation decay in the rail, reduce the vertical vibration of rail and track bed, and control the development of rail corrugation.

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