Properties of vehicle support suspensions

2021 ◽  
pp. 20-24
Author(s):  
Keyword(s):  
Transfer Function ◽  
Spectral Density ◽  
Transmission Coefficient ◽  
Polyurethane Foam ◽  
Vibration Damping ◽  
Damping Properties ◽  
Frequency Range ◽  
The Masses ◽  
Deformation Coefficient ◽  
Damping Of Vibrations

The processes of damping of vibrations of sprung masses with polyurethane foam support cushions in the frequency range of vibrations with an optimal transfer function are investigated. The amplitude-phase-frequency characteristics of the masses are determined during vibrations with the subsequent presentation of transient processes, according to which the damping time of the vibrations of the sprung masses is determined. The used support cushions made of polyurethane foam reduce the minimum damping time of vibrations of the sprung masses on 1520 %, they are more wear-resistant and have greater damping properties than rubber support cushions. Keywords: spectral density, exposure frequency, transmission coefficient, deformation coefficient, vibration damping time, polyurethane foam. [email protected]

Density-based discrimination of protein and RNA in the ribosome

1992 ◽  
Vol 50 (1) ◽  
pp. 464-465
Author(s):  
Joachim Frank
Keyword(s):  
Transfer Function ◽  
Spatial Frequency ◽  
Three Dimensional ◽  
Wiener Filter ◽  
Dark Field Image ◽  
Dark Field ◽  
Frequency Range ◽  
Bright Field ◽  
Contrast Transfer Function ◽  
Pass Filter

Cryo-electron microscopy combined with single-particle reconstruction techniques has allowed us to form a three-dimensional image of the Escherichia coli ribosome.In the interior, we observe strong density variations which may be attributed to the difference in scattering density between ribosomal RNA (rRNA) and protein. This identification can only be tentative, and lacks quantitation at this stage, because of the nature of image formation by bright field phase contrast. Apart from limiting the resolution, the contrast transfer function acts as a high-pass filter which produces edge enhancement effects that can explain at least part of the observed variations. As a step toward a more quantitative analysis, it is necessary to correct the transfer function in the low-spatial-frequency range. Unfortunately, it is in that range where Fourier components unrelated to elastic bright-field imaging are found, and a Wiener-filter type restoration would lead to incorrect results. Depending upon the thickness of the ice layer, a varying contribution to the Fourier components in the low-spatial-frequency range originates from an “inelastic dark field” image. The only prospect to obtain quantitatively interpretable images (i.e., which would allow discrimination between rRNA and protein by application of a density threshold set to the average RNA scattering density may therefore lie in the use of energy-filtering microscopes.

Numerical and Experimental Studies of Pipe Vibration Generated by Elongated Orifice

2016 ◽  
Author(s):  
Wenjie Bai ◽  
Quan Duan ◽  
Zaoxiao Zhang
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Flow Rate ◽  
Vibration Response ◽  
Frequency Range ◽  
Fluctuating Pressure ◽  
Outlet Pressure ◽  
Wall Pressure Fluctuations ◽  
Power Spectral ◽  
Pipe Vibration

Hydraulic tests for elongated orifice-induced wall pressure fluctuations and vibration in pipeline have been carried out. The regulating modes of test system consist of maintaining outlet pressure to increase flow rate and maintaining flow rate to decrease outlet pressure. Both regulating modes would increase the possibility of cavitation within elongated orifice, which has been confirmed by numerical simulation in present study. Statistical characteristics of the fluctuating pressure and structure vibration response have been studied. The standard deviation analyses indicate that the amplitude of fluctuating pressure is mainly determined by flow rate. The power spectral density analyses show that the energy of the fluctuating pressure behind elongated orifice is concentrated in lower frequency range and it can be divided into two parts in this test: the pressure pulsation excited by plunger pump and the random fluctuating pressure produced by elongated orifice’s disturbance. The power spectral density of pipe vibration response shows that the lower frequency of pipe vibration response can be ascribed to the fluctuating pressure behind elongated orifice and the characteristic frequencies corresponding to cavitation within elongated orifice are in the higher frequency range.

Optimization of the Robots Fourier Spectrum by Using the Assisted Research, Neural Network, Smart Damper and LabVIEW Instrumentation

2012 ◽  
Vol 245 ◽  
pp. 24-32 ◽  
Author(s):  
Adrian Olaru ◽  
Serban Olaru ◽  
Aurel Oprean
Keyword(s):  
Neural Network ◽  
Transfer Function ◽  
Spectral Density ◽  
Vibration Analysis ◽  
Manufacturing Systems ◽  
Fourier Spectrum ◽  
Industrial Robots ◽  
Vibration Behavior ◽  
Power Spectral ◽  
The World

The most important things in the dynamic research of industrial robots are the vibration behavior, the transfer function and the vibration power spectral density between some of the robot joints and components. In the world this research is made without the assisted research. In each of the study cases in this paper was used the proper virtual Fourier analyzer and was presented one new method of the assisted vibration analysis. With this research it is possible the optimal choosing the base modulus type to avoid the frequencies from the robot spectrum. In the manufacturing systems, the most important facts are the vibration behavior of the robot, the compatibility with some other components of the system. All the VI where achieved in the LabVIEW soft 8.2 version, from National Instruments, USA. This method and the created virtual LabVIEW instrumentation are generally and they are possible to apply in many other dynamic behavior research.

Study on improvement of vibration-damping properties for sports equipment

2020 ◽  
Vol 2020.28 (0) ◽  
pp. 527
Author(s):  
Ikuya KUBOTA ◽  
,Shigeru KAWAHARA ◽  
Akihiro MATSUDA
Keyword(s):  
Vibration Damping ◽  
Damping Properties

Time-dependent barrier passage of one-dimensional fractional damping reactive system

2018 ◽  
Vol 32 (26) ◽  
pp. 1850285
Author(s):  
Chun-Yang Wang ◽  
Zhao-Peng Sun ◽  
Ming Qing ◽  
Yu-Qing Xu
Keyword(s):  
Transmission Coefficient ◽  
Brownian Particle ◽  
Time Dependent ◽  
Reactive System ◽  
Damping Properties ◽  
Flux Method ◽  
Fractional Damping ◽  
One Dimensional ◽  
Reactive Process ◽  
Insight Into

The time-dependent barrier passage of a Brownian particle diffusing in the fractional damping environment is studied by using the reactive flux method. Characteristic quantities such as the rate constant and stationary transmission coefficient are computed for a thimbleful of insight into the barrier escaping dynamics. Results show that the barrier recrossing of the fractional damping reactive system is obviously weakened. And the nonmonotonic varying of the stationary transmission coefficient reveals a close dependence of the escaping process on the fractional damping properties. The time-dependent barrier passage of one-dimensional fractional damping reactive process is found very similar to the two-dimensional non-Ohmic case.

High-voltage synthetic inductor for vibration damping in resonant piezoelectric shunt

2020 ◽  
pp. 107754632095261
Author(s):  
Kevin Dekemele ◽  
Patrick Van Torre ◽  
Mia Loccufier
Keyword(s):  
Piezoelectric Material ◽  
High Voltage ◽  
State Of The Art ◽  
Vibration Damping ◽  
Operational Amplifiers ◽  
Frequency Range ◽  
Resonant Condition ◽  
Passive Components ◽  
Resonance Frequencies ◽  
Resonant Shunt

Resonant piezoelectric shunts are a well-established way to reduce vibrations of mechanical systems suffering from resonant condition. The vibration energy is transferred to the electrical domain through the bonded piezoelectric material where it is dissipated in the shunt. Typically, electrical and mechanical resonance frequencies are several orders apart. As such, finding a suitable high inductance component for the resonant shunt is not feasible. Therefore, these high inductance values are mimicked through synthetic impedances, consisting of operational amplifiers and passive components. A downside of these synthetic impedances is that standard operational amplifiers can only handle up to 30 V peak to peak and the state-of-the-art amplifiers up to 100 Vpp. However, as mechanical structures tend to become lighter and more flexible, the order induced voltages over the piezoelectric material electrode voltages increase above these limitations. In this research, a high-voltage synthetic inductor is proposed and built by combining the bridge amplifier configuration and the output voltage boost configuration around a single operational amplifier gyrator circuit, effectively quadrupling the range of the synthetic inductor to 400 Vpp. The impedance of the circuit over a frequency range is numerically and experimentally investigated. The synthetic inductor is then connected to a piezoelectric material bonded to a cantilever beam. Numerical and experimental investigation confirms the high-voltage operation of the implemented circuit and its suitability as a vibration damping circuit.

scholarly journals The Time-Robustness Analysis of Individual Identification Based on Resting-State EEG

2021 ◽  
Vol 15 ◽  
Author(s):  
Yang Di ◽  
Xingwei An ◽  
Wenxiao Zhong ◽  
Shuang Liu ◽  
Dong Ming
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Resting State ◽  
Individual Identification ◽  
Frequency Range ◽  
Cross Spectrum ◽  
Power Spectral ◽  
Phase Lags ◽  
Individual Features

An ongoing interest towards identification based on biosignals, such as electroencephalogram (EEG), magnetic resonance imaging (MRI), is growing in the past decades. Previous studies indicated that the inherent information about brain activity may be used to identify individual during resting-state of eyes open (REO) and eyes closed (REC). Electroencephalographic (EEG) records the data from the scalp, and it is believed that the noisy EEG signals can influence the accuracies of one experiment causing unreliable results. Therefore, the stability and time-robustness of inter-individual features can be investigated for the purpose of individual identification. In this work, we conducted three experiments with the time interval of at least 2 weeks, and used different types of measures (Power Spectral Density, Cross Spectrum, Channel Coherence and Phase Lags) to extract the individual features. The Pearson Correlation Coefficient (PCC) is calculated to measure the level of linear correlation for intra-individual, and Support Vector Machine (SVM) is used to obtain the related classification accuracy. Results show that the classification accuracies of four features were 85–100% for intra-experiment dataset, and were 80–100% for fusion experiments dataset. For inter-experiments classification of REO features, the optimized frequency range is 13–40 Hz for three features, Power Spectral Density, Channel Coherence and Cross Spectrum. For inter-experiments classification of REC, the optimized frequency range is 8–40 Hz for three features, Power Spectral Density, Channel Coherence and Cross Spectrum. The classification results of Phase Lags are much lower than the other three features. These results show the time-robustness of EEG, which can further use for individual identification system.

scholarly journals A Study Regarding the Mechanical Properties of a Hybrid Matrix with Various Volume Proportions of Dammar

2020 ◽  
Vol 57 (1) ◽  
pp. 133-140
Author(s):  
Dumitru Bolcu ◽  
Marius Marinel Stanescu ◽  
Ion Ciuca ◽  
Cosmin Mihai Miritoiu ◽  
Alin Dinita ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Vibration Mode ◽  
Vibration Damping ◽  
The Other ◽  
Damping Properties ◽  
Elongation At Break ◽  
Hybrid Resin ◽  
Natural Resin ◽  
Volume Proportion

This paper studies the influence of the volume proportion between components on the mechanical behaviour of a hybrid resin obtained by combining the natural resin Dammar and epoxy resin. We analyse three sets of hybrid resin samples, in which we used a Dammar volume proportion of 60%, 70%, and 80% respectively and epoxy resin (employed together with its associated reinforcement in order to generate a quick process of polymerization). Following the tensile test we found the characteristic curves, the tensile strength and the elongation at break for each of the three types of resins. We also looked into the vibration damping properties of bars made of this resin. We experimentally determined the frequency and the damping coefficient of the first particular vibration mode for one bar taken out of each set of resins, with one end fixed and the other free. On the basis of the results, we calculated the loss coefficient for each type of resin.

Vibration Damping Properties of NiCrAlY Coating Deposited by Arc Ion Plating

2017 ◽  
Vol 46 (5) ◽  
pp. 1188-1191 ◽  
Author(s):  
Du Guangyu ◽  
Tan Zhen ◽  
Ba Dechun ◽  
Liu Kun ◽  
Han Qingkai
Keyword(s):  
Vibration Damping ◽  
Damping Properties ◽  
Arc Ion Plating ◽  
Ion Plating ◽  
Nicraly Coating
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