Low frequency vibration suppression shape filter and high frequency vibration suppression shape filter

2005 ◽  
Author(s):  
Li Zhou ◽  
E.A. Misawa
Keyword(s):  
High Frequency ◽  
Vibration Suppression ◽  
Low Frequency ◽  
High Frequency Vibration ◽  
Low Frequency Vibration

On Vibrational and Dynamic Characteristics of Engines with Deactivated Cylinders

2020 ◽  
pp. 26-34
Author(s):  
A.I. Yamanin
Keyword(s):  
Dynamic Characteristics ◽  
High Frequency ◽  
Low Frequency ◽  
Vibration Velocity ◽  
Toxic Substances ◽  
Vibration Displacement ◽  
Engine Torque ◽  
High Frequency Vibration ◽  
Low Frequency Vibration ◽  
Loading Modes

The article examines some features of dynamics of engines with shut-off cylinders. This technology can promote reduction of fuel consumption and emission of toxic substances with exhaust fumes at partial speed and loading modes. However, the dynamics of such engines have hardly been considered in previous works. Using calculations (solid state modeling, simulation of motion using software for studying dynamics of mechanisms, as well as the finite element method), the indicators of uniformity of stroke and torque, vibration displacement and vibration velocity of various points of the structure at low- and high-frequency vibration are determined. It is shown that when deactivating a different number of cylinders, the uniformity of the engine torque worsens (to a varying degree) and the load on the crankshaft bearings increases. The average quadratic values of vibration velocity of the bearings at low-frequency vibration and the vibration velocity of the lateral walls of the housing parts at high-frequency vibration increases as well. While engines with deactivated cylinders definitely have advantages in efficiency and environmental performance, they do not improve vibrational and dynamic characteristics, which is particularly evident at low rotational speeds of the shaft and at small loads.

Research on High-Frequency Vibratory Stress Relief of Small Cr12MoV Quenched Specimens

2012 ◽  
Vol 157-158 ◽  
pp. 1157-1161 ◽  
Author(s):  
Wen He ◽  
Bang Ping Gu ◽  
Jian Yi Zheng ◽  
Run Jie Shen
Keyword(s):  
Residual Stress ◽  
High Frequency ◽  
Low Frequency ◽  
Stress Relief ◽  
Vibration Level ◽  
High Frequency Vibration ◽  
Low Frequency Vibration ◽  
Before And After

Considering that most of the research on vibratory stress relief (VSR) is excited by low-frequency vibration at present, high-frequency-exciting VSR on small Cr12MoV quenched specimens was studied. A high-frequency vibration table system was adopted as the exciter of the VSR. To increase the vibration level, a novel vibration level amplifying device was put forward. High-frequency VSR on the same group of small Cr12MoV quenched specimens was carried out under various vibration levels. The residual stress before and after vibration was comparatively analyzed. The results showed that the high-frequency vibration had the better effect on eliminating and homogenizing the residual stress and that increasing the vibration level of high-frequency-exciting could improve the effect of high-frequency VSR.

Research on Output Characteristics of Piezoelectric Accelerometers for Low-Frequency Vibration

2010 ◽  
Vol 139-141 ◽  
pp. 2460-2463
Author(s):  
Chao Fu Zhu ◽  
Xu Qin ◽  
Li Wen Zheng
Keyword(s):  
Eddy Current ◽  
High Frequency ◽  
Low Frequency ◽  
Vibration Measurement ◽  
Current Sensor ◽  
Vibration Frequencies ◽  
High Frequency Vibration ◽  
Eddy Current Sensor ◽  
Low Frequency Vibration ◽  
Output Characteristics

Piezoelectric accelerometers are widely used for the measurement of middle- or high-frequency vibration. It is necessary to verify via experiments whether piezoelectric accelerometers can accurately measure low-frequency vibration. An experiment is designed to test the output characteristics of piezoelectric accelerometers for vibration of 1~5 Hz frequency, using a standard vibrator at low frequency (≤5Hz) and an accurately calibrated non-contact eddy current sensor as datum sensor. The experiment shows that the output characteristics of piezoelectric accelerometers are relatively stable when measuring vibration of 4~5Hz frequency. However, the output characteristics of accelerometers change with the frequencies and accelerations of vibration when the vibration frequencies are 1~3 Hz. It will affect the accuracy of vibration measurement.

Vibrodynamic parameters of engines with alternative operating processes

2020 ◽  
pp. 30-33
Author(s):  
A.I. Yamanin
Keyword(s):  
High Frequency ◽  
Water Injection ◽  
Low Frequency ◽  
Mean Square ◽  
High Frequency Vibration ◽  
Low Frequency Vibration ◽  
Engine Cylinder ◽  
Torque Load ◽  
Stroke Engine

The vibrodynamic parameters of six-stroke engines with water injection into cylinders and engines with cylinder shutdown are considered. In both cases, a deterioration in the uniformity of stroke and torque, a decrease in the loading of the necks and bearings of the crankshaft, as well as low-frequency vibration, were found. High-frequency vibration also worsens, but less significantly. Keywords six-stroke engine, cylinder shutdown, uniformity of stroke and torque, load on the necks and bearings of the crankshaft, mean square value, vibration speed of bearings. [email protected]

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.

scholarly journals Stiffness-based Spring Design Optimization using Taguchi Method to reduce Low-Frequency Vibration

2019 ◽  
Vol 5 (2) ◽  
Author(s):  
Ahmad Yusuf Ismail ◽  
Al Munawir ◽  
Noerpamoengkas A
Keyword(s):  
Taguchi Method ◽  
High Frequency ◽  
Vibration Isolation ◽  
Low Frequency ◽  
Stiffness Coefficient ◽  
Frequency Range ◽  
High Noise ◽  
Low Frequency Vibration ◽  
Optimization Variable ◽  
Vibration Transmissibility

Low-frequency vibration has been troublesome for a mechanical system. Despite the measurement difficulties, low-frequency vibration also creates several environmental effects such as high noise level that is harmful to the human body. One of the methods to reduce vibration is tuning the vibration isolation i.e. spring and damping coefficient. However, the latter method is found to be effective only for the mid-high frequency range. Therefore, this paper proposes an optimization of the spring a.k.a. stiffness coefficient in order to reduce the low-frequency vibration. The Taguchi method is used as an optimization tool since it offers simplicity yet powerful for any field of application, particularly in engineering. Two significant parameters in the spring geometry were selected as the optimization variable in the Taguchi method and evaluated using vibration transmissibility concept. The result shows that the Taguchi method has been successfully obtained the optimum value for the spring geometry purposely to reduce the vibration transmissibility.

Low-frequency vibration suppression of a multi-layered elastic metamaterial shaft with discretized scatters

2018 ◽  
Vol 52 (5) ◽  
pp. 055105 ◽  
Author(s):  
Lixia Li ◽  
Ruixiang Lv ◽  
Anjiang Cai ◽  
Miaoxia Xie ◽  
Yangyang Chen ◽  
...  
Keyword(s):  
Vibration Suppression ◽  
Low Frequency ◽  
Low Frequency Vibration

Dynamic Variational-Asymptotic Procedure for Laminated Composite Shells—Part II: High-Frequency Vibration Analysis

2008 ◽  
Vol 76 (1) ◽  
Author(s):  
Chang-Yong Lee ◽  
Dewey H. Hodges
Keyword(s):  
High Frequency ◽  
Vibration Analysis ◽  
Shell Theory ◽  
Low Frequency ◽  
Normal Displacement ◽  
Difficult Situation ◽  
Long Wavelength ◽  
First Approximation ◽  
Low Frequency Vibration ◽  
Characteristic Wavelength

Shell theories intended for low-frequency vibration analysis are frequently constructed from a generalization of the classical shell theory in which the normal displacement (to a first approximation) is constant through the thickness. Such theories are not suitable for the analysis of complicated high-frequency effects in which displacements may change rapidly along the thickness coordinate. Clearly, to derive by asymptotic methods, a shell theory suitable for high-frequency behavior requires a different set of assumptions regarding the small parameters associated with the characteristic wavelength and timescale. In Part I such assumptions were used to perform a rigorous dimensional reduction in the long-wavelength low-frequency vibration regime so as to construct an asymptotically correct energy functional to a first approximation. In Part II the derivation is extended to the long-wavelength high-frequency regime. However, for short-wavelength behavior, it becomes very difficult to represent the three-dimensional stress state exactly by any two-dimensional theory; and, at best, only a qualitative agreement can be expected. To rectify this difficult situation, a hyperbolic short-wave extrapolation is used. Unlike published shell theories for this regime, which are limited to homogeneous and isotropic shells, all the formulas derived herein are applicable to shells in which each layer is made of a monoclinic material.

Fluid Power Control of a Hyper-Active Seat for Low-Frequency Vibration Suppression

2004 ◽  
Vol 37 (22) ◽  
pp. 501-506
Author(s):  
Samuel Klooster ◽  
Kris Kozak ◽  
Joshua Vaughan ◽  
Peter Sanders ◽  
William Singhose
Keyword(s):  
Power Control ◽  
Vibration Suppression ◽  
Low Frequency ◽  
Fluid Power ◽  
Low Frequency Vibration
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