scholarly journals Resonance Effect Decrease and Accuracy Increase of Piezoelectric Accelerometer Measurement by Appropriate Choice of Frequency Range

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Zine Ghemari ◽  
Saad Salah ◽  
Rabah Bourenane
Keyword(s):  
Measurement Error ◽  
Resonance Effect ◽  
Physical Principle ◽  
Resonance Phenomenon ◽  
Frequency Range ◽  
Piezoelectric Accelerometer ◽  
Damping Rate ◽  
Accuracy Increase ◽  
Precise Relationship ◽  
Relationship Of

A suitable piezoelectric accelerometer mathematical model is proposed to extract a relationship of motion relative frequency as a function of natural frequency. This relationship helps to select appropriate accelerometer frequency range that minimizes measurement error and improves accuracy. It also allows deducing a formula relating the damping rate and the measurement error of the accelerometer. To protect the accelerometer from failure, the resonance phenomenon effect must be minimized. In order to achieve this objective, physical principle is modeled to find a precise relationship which can determine the accelerometer appropriate frequency range. The developed model was simulated and the obtained results have showed that the selection of the frequency range has minimized the measurement error, increased the accelerometer accuracy, and reduced the resonance effect. Finally a comparative study was conducted to show the importance of the obtained results compared to recent literatures.

New Formula for the Piezoresistive Accelerometer Motion Acceleration and Experimental Validation

2017 ◽  
Vol 16 (01) ◽  
pp. 57-65 ◽  
Author(s):  
Zine Ghemari ◽  
Fethi Chouaf ◽  
Salah Saad
Keyword(s):  
Measurement Error ◽  
Experimental Validation ◽  
Vibration Measurement ◽  
Frequency Range ◽  
Acceleration Measurement ◽  
Measurement Quality ◽  
Damping Rate ◽  
The Right ◽  
New Formula ◽  
First Time

A piezoresistive accelerometer is the first element of a vibration measurement chain, and its improvement can enhance measurement quality. In this paper, we have developed a new formula that links the movement acceleration as a function of the natural frequency and the damping rate of the piezoresistive accelerometer in first time, and movement acceleration as a function of the measurement error in second time. This model allows the decrease of the acceleration measurement error and increases the accelerometer accuracy by choosing the right damping rate and frequency range. Finally, this new formula allows proposing new parameters for more accurate and reliable piezoresistive accelerometer.

Improvement of the Vibratory Analysis by Enhancement of Accelerometer Characteristics

2020 ◽  
Vol 18 (1) ◽  
pp. 39-42
Author(s):  
Salah Belkhiri ◽  
Zine Ghemari ◽  
Salah Saad ◽  
Ghania Boudechiche
Keyword(s):  
Mathematical Model ◽  
Measurement Error ◽  
Comparative Study ◽  
Damping Ratio ◽  
Operating Principle ◽  
Piezoelectric Accelerometer ◽  
Analysis Technique ◽  
Vibratory Analysis ◽  
Damping Rate ◽  
The Mathematical Model

In this work, the mathematical model suitable for the operating principle of the piezoelectric accelerometer is extracted then this model which connects the accuracy and the measurement error according of the frequency ration and the damping rate is validated by simulation. The model developed makes it possible to improve the performances of the accelerometer such as precision, sensitivity and reliability as well as to propose a new conception of the latter. A comparative study is made to show the importance of our results compared to literature, these results have showed that a suitable and appropriate choice of damping ratio develops the accelerometer parameters and enhances the vibratory analysis technique.

III. Villanovan Veii

1961 ◽  
Vol 29 ◽  
pp. 20-25 ◽  
Author(s):  
J. B. Ward-Perkins
Keyword(s):  
Bronze Age ◽  
Iron Age ◽  
Late Antiquity ◽  
Central Italy ◽  
Early Iron Age ◽  
Long Period ◽  
The Social ◽  
Precise Relationship ◽  
Relationship Of ◽  
The City

The roads and gates described in the previous section are of very varied dates, and many of them were in use over a long period. They have been described first because they constitute the essential framework for any serious topographical study of Veii. Within this framework the city developed, and in this and the following sections will be found described, period by period, the evidence for that development, from the first establishment of Veii in Villanovan times down to its final abandonment in late antiquity.Whatever the precise relationship of the Villanovan to the succeeding phases of the Early Iron Age in central Italy in terms of politics, race or language, it is abundantly clear that it was within the Villanovan period that the main lines of the social and topographical framework of historical Etruria first took shape. Veii is no exception. Apart from sporadic material that may have been dropped by Neolithic or Bronze Age hunters, there is nothing from the Ager Veientanus to suggest that it was the scene of any substantial settlement before the occupation of Veii itself by groups of Early Iron Age farmers, a part of whose material equipment relates them unequivocally to the Villanovan peoples of coastal and central Etruria.

Investigation of Relationship between Instrumented Indentation Nominal Hardness and Reduced Elastic Modulus with Large Apex Angle Indenter

2012 ◽  
Vol 198-199 ◽  
pp. 193-196
Author(s):  
De Jun Ma ◽  
Jun Hong Guo ◽  
Wei Chen ◽  
Zhong Kang Song
Keyword(s):  
Elastic Modulus ◽  
Measurement Error ◽  
Apex Angle ◽  
Instrumented Indentation ◽  
Included Angle ◽  
Cube Corner ◽  
Order Polynomial ◽  
Strength Material ◽  
Relationship Of ◽  
The Relationship

Based on dimensional analysis, finite element numerical calculation is undertaken on elastic–plastic solids to investigate the relationship between instrumented indentation nominal hardness Hn and reduced elastic modulus Er for three different apex angle indenters. The half-included angles of axisymetric conical indenter models are 62.9°, 70.3°and 85.566° which are corresponding to the real indenters of cube corner indenter with 60° face angle, Berkovich indenter with 65.27° face angle and cube corner indenter with 85° face angle, respectively. The relationship between a nominal hardness/reduced elastic modulus (Hn/Er) and elastic work/total indentation work (We/Wt) is established with a sixth-order polynomial form for each apex angle indenter. For rigid indenter of instrumented indentation model, reduced elastic modulus Er=1/[(1+v2)/E], where E and v are elastic modulus and Poisson’s ratio of the indented material. Therefore, Hn/Er–We/Wt relationship can be used to give estimates of E. Accuracy estimation for the each relationship of each half-included angle indenter shows that the large half-included angle of 85.566° gives better Er measurement error of +11.56% for a low yield strength material(e.g., materials for which σy=100MPa, n=0 and E=200GPa), while for the smaller half-included angle of 62.9° or 70.3° indenter, the measurement error is > ±12.74%. The research in this paper confirms that Hn/Er–We/Wt relationship of large apex angle indenter such as 85.566° half-included angle is recommended to be used for estimating the elastic modulus E of indented material.

The resonant valley suppression of a hydraulic shaking table by using adaptive spectral line enhancer

2018 ◽  
Vol 232 (10) ◽  
pp. 1379-1388
Author(s):  
Tao Wang ◽  
Jinchun Song
Keyword(s):  
Spectral Line ◽  
Coupling Effect ◽  
Resonance Effect ◽  
Shaking Table ◽  
Resonance Phenomenon ◽  
Resonant System ◽  
Stability Range ◽  
Elastic Load ◽  
Hydraulic Servo ◽  
The Stability

As an electro-hydraulic servo shaking table takes on an elastic load in a vibration test of a 2-mass dynamic system, a mutual coupling effect is exerted between the shaking table and the specimen, which will form a resonant system to weaken the dynamic characteristics of the system. As required by the system bandwidth, the resonant system contains a resonance valley and a resonance peak, and its amplitude commonly surmounts the stability range of the system’s acceleration amplitude. In this article, the resonance phenomenon is analyzed, and the structure and the parameters of the three-state controller are designed on the basis of a pole assignment system. The adaptive spectral line enhancer is adopted to suppress the resonant valley, and the power spectrum is analyzed to experimentally verify that it exerts an anti-resonance effect.

The Noise Characteristics Research in Subway Cars

2014 ◽  
Vol 1051 ◽  
pp. 431-434
Author(s):  
Jian Hui Tian ◽  
Lian Jian ◽  
Bing Li
Keyword(s):  
Real Time ◽  
High Frequency ◽  
Noise Spectrum ◽  
Frequency Range ◽  
Noise Characteristics ◽  
Spectrum Distribution ◽  
Spectrum Characteristics ◽  
Relationship Of ◽  
The Relationship

The noise of different points in four sections of Shenzhen subway was tested by this paper. Real-time SPL and noise spectrum distribution curves at bogie were given, while the equivalent SPL curve was also shown. The relationship of subway speed and noise SPL was investigated. The regular of noise spectrum characteristics and SPL was obtained. The results show that the noise SPL increases with the increase of the speed. Looking from the frequency range, the frequency corresponding to larger noise SPL amplitude mainly concentrates in the lower frequency while the subway stopping, the frequency corresponding to larger noise SPL amplitude mainly concentrates in high frequency while the subway running.

Improvement of Method Queues by Progress of the Piezoresistive Accelerometer Parameters

2017 ◽  
Vol 16 (03) ◽  
pp. 227-235 ◽  
Author(s):  
Mabrouk Defdaf ◽  
Zine Ghemari ◽  
Aoel. Elias Hadjaj ◽  
Salah Saad
Keyword(s):  
Computer Simulation ◽  
Vibration Analysis ◽  
Impulse Responses ◽  
Frequency Range ◽  
Damping Rate ◽  
The Difference ◽  
Maintenance Performance

In this paper the queues are used as a method to improve maintenance performance. The information collected by vibration analysis is used to check the system status and see whether a maintenance operation is to be organized. Thus, for a precise decision, the improvement of accelerometer parameters is required. In order to solve this issue, the piezoresistive accelerometer step and impulse responses are enhanced by using appropriate parameters (damping rate and frequency range). Computer simulation tests were conducted to confirm this approach. The obtained results have shown the difference between the accelerometer with the proposed parameters and the accelerometer used in the experiment. It can be concluded that the proposed parameters provide stable and accurate accelerometer.

scholarly journals Design of An Ultra-Thin and Broadband Absorption Materials For Middle-Temperature Applications

2021 ◽  
Author(s):  
Yanmin Jia ◽  
Zhaoning Yang ◽  
Lu Gao ◽  
Wei Ren ◽  
Ruiduan Zhang ◽  
...  
Keyword(s):  
Reflection Loss ◽  
Frequency Selective Surface ◽  
Complex Permeability ◽  
Frequency Range ◽  
Broadband Absorption ◽  
Radar Absorbing Material ◽  
Temperature Environment ◽  
Absorbing Material ◽  
Relationship Of ◽  
The Relationship

Abstract A radar absorbing material (RAM) is designed based on the magnetic ceramic and frequency selective surface (FSS). The phase composition and micromorphology were characterized, respectively. The complex permittivity and complex permeability of magnetic ceramic were tested and studied from 25 ℃ to 500 ℃ temperature. Based on the experimental and simulation results, the changes of reflection loss along with the structure parameters of RAM are analyzed at 500 ℃. The relationship of reflection loss varies with temperature are studied. The analytical results show that the absorption property of the RAM increases with the increase of temperature. An optimal absorption of RAM is obtained at 500℃. When the thickness of RAM is 1.5 mm, the reflection loss lower than -10 dB can be obtained in the frequency range from 8.2 ~ 16 GHz. More than 90% microwave energy can be consumed in the RAM which may be applied in the high temperature environment.

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