Method To Detect the Vibration State Based on the Shifting Distance of Characteristic Frequency

2021 ◽  
Author(s):  
Jichao Wu ◽  
Zhenghui Xue ◽  
Wu Ren ◽  
Weiming Li ◽  
Lixuan Guo
Keyword(s):  
Characteristic Frequency ◽  
Vibration State

Research on Wireless Vibration Monitoring System for Devices in the Engine Room

2012 ◽  
Vol 503-504 ◽  
pp. 1651-1654
Author(s):  
Guo Yong Zhang ◽  
Shuo Wu
Keyword(s):  
Monitoring System ◽  
Vibration Sensor ◽  
Vibration Monitoring ◽  
Vibration State ◽  
Engine Room ◽  
On Line ◽  
The Common

The vibration can influence the running of devices in the engine room. It is necessary to monitor the vibration state of all running machineries. Through integrating the Bluetooth technology into the common vibration sensor, a wireless on-line vibration monitoring system is designed to monitor all devices. It will be helpful to avoid severe failure and improve the cruising ability.

scholarly journals Complexity and characteristic frequency studies in ECG signals of mice based on multiple scale factors

2011 ◽  
Vol 54 (6) ◽  
pp. 544-552
Author(s):  
XiaoDong Yang ◽  
AiJun He ◽  
Peng Liu ◽  
TongFeng Sun ◽  
XinBao Ning
Keyword(s):  
Characteristic Frequency ◽  
Multiple Scale ◽  
Ecg Signals ◽  
Scale Factors

Recognition of Bearing Faults of the Same Kind

1991 ◽  
Author(s):  
Ming Bao ◽  
Chun-sheng Zhao
Keyword(s):  
Condition Monitoring ◽  
Characteristic Frequency ◽  
Correct Equation ◽  
Bearing Faults ◽  
Single Fault ◽  
Equipment Utilization ◽  
Bearing Part ◽  
Fault Characteristic

Abstract Condition monitoring has gained much acceptance because of the reduction of maintenance expenses and the increase of rate of equipment utilization. It is very important that the serious degrees of machinery faults is correctly predicted. Two faults in a bearing part is, of course, more serious than the single fault is. If the features of bearing faults of the same kind are not recognized, faults of the same kind are, then, mistaken for a single fault, the serious consequences may be caused. The features of bearing faults of the same kind are presented and the illustrations are given in the paper. Meanwhile, the correct equation of roller’ s fault characteristic frequency is expounded conveniently.

Effects of material texture and packing density on the interfacial polarization of granular soils

Geophysics ◽  
2021 ◽  
pp. 1-58
Author(s):  
Hang Chen ◽  
Qifei Niu
Keyword(s):  
Electrical Conductivity ◽  
Packing Density ◽  
Characteristic Frequency ◽  
Effective Permittivity ◽  
Scale Up ◽  
Interfacial Polarization ◽  
Granular Soils ◽  
Geologic Materials ◽  
Effective Electrical Conductivity ◽  
Material Texture

Many electrical and electromagnetic (EM) methods operate at MHz frequencies, at which the interfacial polarization occurring at the solid-liquid interface in geologic materials may dominate the electrical signals. To correctly interpret electrical/EM measurements, it is therefore critical to understand how the interfacial polarization influences the effective electrical conductivity and permittivity spectra of geologic materials. We have used pore-scale simulation to study the role of material texture and packing in interfacial polarization in water-saturated granular soils. Synthetic samples with varying material textures and packing densities are prepared with the discrete element method. The effective electrical conductivity and permittivity spectra of these samples are determined by numerically solving the Laplace equation in a representative elementary volume of the samples. The numerical results indicate that the effective permittivity of granular soils increases as the frequency decreases due to the polarizability enhancement from the interfacial polarization. The induced permittivity increment is mainly influenced by the packing state of the samples, increasing with the packing density. Material textures such as the grain shape and size distribution may also affect the permittivity increment, but their effects are less significant. The frequency characterizing the interfacial polarization (i.e., the characteristic frequency) is mainly related to the electrical contrast of the solid and water phases. The model based on the traditional differential effective medium (DEM) theory significantly underestimates the permittivity increment by a factor of more than two and overestimates the characteristic frequency by approximately 1 MHz. These inaccurate predictions are due to the fact that the electrical interactions between neighboring grains are not considered in the DEM theory. A simple empirical equation is suggested to scale up the theoretical depolarization factor of grains entering the DEM theory to account for the interaction of neighboring grains in granular soils.

scholarly journals Unbalanced Vibration Identification of Tangential Threshing Cylinder Induced by Rice Threshing Process

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Zhong Tang ◽  
Haotian Zhang ◽  
Yuepeng Zhou
Keyword(s):  
Service Life ◽  
Vibration Amplitude ◽  
Rotation Speed ◽  
Resonance Phenomenon ◽  
Test Results ◽  
Axial Vibration ◽  
Ansys Software ◽  
Cylinder Axis ◽  
Vibration State ◽  
Rice Stalks

Unbalanced vibration of tangential threshing cylinder increased the grain loss, shortened service life of the cylinder, and resulted in structural resonance during the rice threshing process. In this paper, the vibration amplitude and frequency of tangential threshing cylinder shaft were tested, and the vibration state of tangential threshing cylinder was identified. The restricted and working modalities of tangential threshing cylinder were solved by ANSYS software. Then, by comparing the resonance phenomenon between the inherent constraint frequency and the rotation speed frequency, the shaft vibration under the idle condition of tangential threshing cylinder was tested and analyzed. According to the axial vibration and axial trajectory of the cylinder, the inherent properties and characteristics of unbalanced vibration were revealed. Test results showed that when the tangential threshing cylinder was at idling and no-load state, the amplitude of vibration in the feed direction of straw flow was -0.049~0.060 mm, and the average vibration amplitude was 0.013 mm. As rice flowed along the tangential threshing cylinder, the vibration amplitude slightly increased. The trend and phase of each trajectory were similar, although the amplitude of each trajectory was different. The tangential threshing cylinder axis trajectory was flat oval. Unbalanced vibration was induced by the rice stalks in the concave gap.

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