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Tytuł:
Influence of temperature variation on vibration of rectangular plate of visco-elastic material
Autorzy:
Khanna, Anupam
Singhal, Ashish
Powiązania:
https://bibliotekanauki.pl/articles/1030670.pdf
Data publikacji:
2020
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
clamped
frequency parameter
taper parameters
visco-elastic
Opis:
This paper deals with free vibration modes and natural frequencies of a thin visco-elastic, non-homogeneous rectangular plate with clamped ends. First two modes of frequency parameter of vibration are derived on the basis of Rayleigh-Ritz technique. Since the effect of temperature decreases the efficiency and durability of the structure, influence of bi-parabolic temperature variations on vibration of rectangular plate is analyzed. Tapering in rectangular plate is assumed bi-exponentially in x-and y-direction. Effect of non-homogeneity is discussed with exponential variation in density of the plate’s material i.e. visco-elastic material “Duralium” which is an alloy of aluminum. Vibration modes of clamped plate are calculated for various values of thermal gradient, taper parameters and non-homogeneity constant. Results are explained with the help of the graphs.
Źródło:
World Scientific News; 2020, 139, 2; 61-75
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modal characterization of sandwich skew plates
Autorzy:
Pavan-Kumar, Dhotre
Srinivasa, Chikkol V.
Powiązania:
https://bibliotekanauki.pl/articles/2114835.pdf
Data publikacji:
2021
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
natural frequency
non-dimensional frequency parameter
antisymmetric laminate
fiber orientation angle
skew angle
Opis:
The current work focuses on the experimental and finite element free vibration studies of laminated composite sandwich skew plates. The comparison was made between the experimental values obtained by the Fast Fourier transform (FFT) analyzer and a finite el-ement solution obtained from CQUAD8 finite element of The MacNeal-Schwendler Corporation (MSC) / NASA STRucture Analysis (NAS-TRAN) software. The influence of parameters such as aspect ratio (AR) (a/b), skew angle (α), edge condition, laminate stacking sequence, and fiber orientation angle (θ°) on the natural frequencies of sandwich skew plates was studied. The values obtained by both the finite el-ement and experiment approaches are in good agreement. The natural frequencies increase with an increase in the skew angle for all giv-en ARs.
Źródło:
Acta Mechanica et Automatica; 2021, 15, 3; 143--153
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parametry częstotliwościowe przetworników prądowych wykonanych w technologii PCB1 i HDI2
Frequency parameters of current-mode converters made in PCB1 i HDI2 technologies
Autorzy:
Lisowiec, A.
Nowakowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/186475.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technik Innowacyjnych EMAG
Tematy:
przetworniki prądowe
parametry częstotliwościowe
pomiary
current-mode converters
frequency parameter
measurements
Opis:
W artykule przedstawiono wyniki pomiarów oraz analizę charakterystyk częstotliwościowych przetworników prądowych wykonanych w technologii PCB HDI. Najpierw omówiono konstrukcję bez-rdzeniowych przetworników wykonanych w technologii PCB HDI. Następnie określono wartości elementów układu zastępczego przetwornika bezrdzeniowego. Na koniec przytoczono charakterystyki częstotliwościowe przetworników bezrdzeniowych wykonanych w tradycyjnej technologii PCB oraz w technologii HDI.
The article presents the measurement results and analysis of frequency characteristics of current-mode converters made with the use of the PCB HDI technology. First the structure of rodless PCB HDI converters was discussed. Then the values of the elements of an equivalent circuit in a rodless converter were determined. Finally, the authors discussed the frequency characteristics of rodless converters made with the use of either the traditional PCB technology or the HDI technology.
Źródło:
Mechanizacja i Automatyzacja Górnictwa; 2014, R. 52, nr 5, 5; 12-17
0208-7448
Pojawia się w:
Mechanizacja i Automatyzacja Górnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free Vibration Analysis of Mindlin Plates Resting on Pasternak Foundation Using Coupled Displacement Method
Autorzy:
Rajesh, K.
Saheb, K. M.
Powiązania:
https://bibliotekanauki.pl/articles/139827.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fundamental frequency parameter
Mindlin plate
linear free vibrations
computational fluid dynamics
CFD
Pasternak foundation
parametr częstotliwości podstawowej
płyta Mindlina
liniowe drgania swobodne
obliczeniowa mechanika płynów
podłoże Pasternaka
Opis:
The authors developed a simple and efficient method, called the Coupled Displacement method, to study the linear free vibration behavior of the moderately thick rectangular plates in which a single-term trigonometric/algebraic admissible displacement, such as total rotations, are assumed for one of the variables (in both X,Y directions), and the other displacement field, such as transverse displacement, is derived by making use of the coupling equations. The coupled displacement method makes the energy formulation to contain half the number of unknown independent coefficients in the case of a moderately thick plate, contrary to the conventional Rayleigh-Ritz method. The smaller number of undetermined coefficients significantly simplifies the vibration problem. The closed form expression in the form of fundamental frequency parameter is derived for all edges of simply supported moderately thick rectangular plate resting on Pasternak foundation. The results obtained by the present coupled displacement method are compared with existing open literature values wherever possible for various plate boundary conditions such as all edges simply supported, clamped and two opposite edges simply supported and clamped and the agreement found is good.
Źródło:
Archive of Mechanical Engineering; 2018, LXV, 1; 107-128
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel method for separability of signal components to estimate radiation from a high-frequency subsystem
Autorzy:
Daneshvar, Milad
Parhizgar, Naser
Oraizi, Homayoon
Powiązania:
https://bibliotekanauki.pl/articles/140523.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electromagnetic interference
electromagnetic radiation
parameter estimation
multi-component signals
frequency response
radio frequency
Opis:
Specific requirements are designed and implemented in electronic and telecommunication systems for received signals, especially high-frequency ones, to examine and control the signal radiation. However, as a serious drawback, no special requirements are considered for the transmitted signals from a subsystem. Different industries have always been struggling with electromagnetic interferences affecting their electronic and telecommunication systems and imposing significant costs. It is thus necessary to specifically investigate this problem as every device is continuously exposed to interferences. Signal processing allows for the decomposition of a signal to its different components to simulate each component. Radiation control has its specific complexities in systems, requiring necessary measures from the very beginning of the design. This study attempted to determine the highest radiation from a subsystem by estimating the radiation fields. The study goal was to investigate the level of radiations received and transmitted from the adjacent systems, respectively, and present methods for control and eliminate the existing radiations. The proposed approach employs an algorithm which is based on multi-component signals, defect, and the radiation shield used in the subsystem. The algorithm flowchart focuses on the separation and of signal components and electromagnetic interference reduction. In this algorithm, the detection process is carried out at the bounds of each component, after which the separation process is performed in the vicinity of the different bounds. The proposed method works based on the Fourier transform of impulse functions for signal components decomposition that was employed to develop an algorithm for separation of the components of the signals input to the subsystem.
Źródło:
Archives of Electrical Engineering; 2019, 68, 3; 497-510
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Practical use of RLC-models of transformers’ windings for determination of local displacements
Autorzy:
Banaszak, S.
Gawrylczyk, K. M.
Powiązania:
https://bibliotekanauki.pl/articles/97720.pdf
Data publikacji:
2013
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
transformer’s diagnostic
frequency response analysis (FRA)
lumped parameter models
Opis:
The diagnostics of power transformers is a very fast developing branch, due to increasing average age of assets and changes in asset management strategies, nowadays companies introduce asset management based on a real technical condition. One of important methods used for diagnostics of a transformer’s active part is Frequency Response Analysis (FRA). It allows determination of mechanical condition of windings, their displacements, deformations and electric faults, as well as some problems with internal leads and connections, core and bushings. For the aim of windings impedance modeling the RLC models are applied. The idea of lumped parameters models was presented in [6]. The new universal model basing on circuit solution is developed in this paper. Lumped parameters used in calculations are obtained with finite element method and Maxwell package. The examples of models created for simple windings were compared to real measurements.
Źródło:
Computer Applications in Electrical Engineering; 2013, 11; 100-109
1508-4248
Pojawia się w:
Computer Applications in Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Accurate Frequency Estimation Based On Three-Parameter Sine-Fitting With Three FFT Samples
Autorzy:
Liu, X.
Ren, Y.
Chu, C.
Fang, W.
Powiązania:
https://bibliotekanauki.pl/articles/220451.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
frequency estimation
CRLB
three-parameter sine-fitting
RMSE
golden section
Opis:
This paper presents a simple DFT-based golden section searching algorithm (DGSSA) for the single tone frequency estimation. Because of truncation and discreteness in signal samples, Fast Fourier Transform (FFT) and Discrete Fourier Transform (DFT) are inevitable to cause the spectrum leakage and fence effect which lead to a low estimation accuracy. This method can improve the estimation accuracy under conditions of a low signal-to-noise ratio (SNR) and a low resolution. This method firstly uses three FFT samples to determine the frequency searching scope, then – besides the frequency – the estimated values of amplitude, phase and dc component are obtained by minimizing the least square (LS) fitting error of three-parameter sine fitting. By setting reasonable stop conditions or the number of iterations, the accurate frequency estimation can be realized. The accuracy of this method, when applied to observed single-tone sinusoid samples corrupted by white Gaussian noise, is investigated by different methods with respect to the unbiased Cramer-Rao Low Bound (CRLB). The simulation results show that the root mean square error (RMSE) of the frequency estimation curve is consistent with the tendency of CRLB as SNR increases, even in the case of a small number of samples. The average RMSE of the frequency estimation is less than 1.5 times the CRLB with SNR = 20 dB and N = 512.
Źródło:
Metrology and Measurement Systems; 2015, 22, 3; 403-416
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inter-harmonic parameter identification method based on transform with local maximum spectrum
Autorzy:
Sun, Lin
Song, Jing
Jin, Yan
Powiązania:
https://bibliotekanauki.pl/articles/2042793.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inter-harmonic
parameter identification
power system
synchrosqueezed transform
time-frequency analysis
Opis:
In order to improve the detection accuracy of harmonics/inter-harmonics in power systems, a new method of harmonic/inter-harmonic detection based on synchrosqueezed transform and the Hilbert operator based on local spectrum maximum is proposed. Firstly, the spectrum of inter-harmonic signals is obtained through short-time Fourier transform, and the local maximum value of the spectrum in the frequency direction is detected. Then, based on the maximum frequency of the spectrum, a new frequency redistribution operator and synchronous extraction operator are constructed. It combines the operators with ridge detection for the decomposition of harmonic/inter-harmonic signals, so as to obtain a series of intrinsic mode function (IMF) components. Finally, the instantaneous amplitude and frequency of the IMF components is obtained by using the Hilbert operator. Meanwhile, according to the instantaneous frequency mutation point in the spectrum, the starting and ending time of transient harmonics/inter-harmonics is located accurately. Based on a low signal-to-noise ratio (SNR), the wavelet packet method (WP), Hilbert Marginal Spectrum method (HMS), synchrosqueezing wavelet transform method (SST), the Hybrid SST method (HSST), enhanced empirical wavelet transform (EEWT) and the proposed method are used to identify the harmonic/inter-harmonic parameters, respectively. The experimental results show that the proposed LMSST method can effectively separate the steady-state and transient harmonic/inter-harmonic signals, and has higher detection accuracy and better noise robustness.
Źródło:
Archives of Electrical Engineering; 2022, 71, 1; 189-209
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An identification procedure of electromagnetic parameters for an induction motor equivalent circuit including rotor deep bar effect
Autorzy:
Rolek, J.
Utrata, G.
Powiązania:
https://bibliotekanauki.pl/articles/141612.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
induction motors
equivalent circuits
parameter identification
frequency-domain analysis
genetic algorithms
Opis:
The paper presents an identification procedure of electromagnetic parameters for an induction motor equivalent circuit including rotor deep bar effect. The presented procedure employs information obtained from measurement realised under the load curve test, described in the standard PN-EN 60034-28: 2013. In the article, the selected impedance frequency characteristics of the tested induction machines derived from measurement have been compared with the corresponding characteristics calculated with the use of the adopted equivalent circuit with electromagnetic parameters determined according to the presented procedure. Furthermore, the characteristics computed on the basis of the classical machine T-type equivalent circuit, whose electromagnetic parameters had been identified in line with the chosen methodologies reported in the standards PN-EN 60034-28: 2013 and IEEE Std 112TM-2004, have been included in the comparative analysis as well. Additional verification of correctness of identified electromagnetic parameters has been realised through comparison of the steady-state power factor-slip and torque-slip characteristics determined experimentally and through the machine operation simulations carried out with the use of the considered equivalent circuits. The studies concerning induction motors with two types of rotor construction – a conventional single cage rotor and a solid rotor manufactured from magnetic material – have been presented in the paper.
Źródło:
Archives of Electrical Engineering; 2018, 67, 2; 279--291
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new method to reduce electromagnetic interference using signal modeling
Autorzy:
Daneshvar, Milad
Parhizgar, Nasser
Oraizi, Homayoon
Powiązania:
https://bibliotekanauki.pl/articles/949874.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electromagnetic radiation
frequency response
interference
multi-component
signals
parameter modeling
transmission lines
Opis:
Controlling and reducing the radiation emitted by various systems helps the board designer improve systems’ performance. One proposed way to achieve these goals is to use an algorithm to control the radiation applied to systems. According to the executive structure of the algorithm and considering the nature of the existing signals in several components, the separation of the signal components is on the agenda of the algorithm. In fact, the goal is to create an intuitive view of the multi-component signals around the systems that enter the systems from different angles and have a detrimental effect on their performance. Using signal processing methods, we will be able to break down the signal into different components and simulate each component separately. To prevent high computational repetitions and increase simulation time in signal component analysis, by reducing the components, we reduce the number of mesh cells in the software and, using linear approximation, determine the exact position of the radiation signal applied to systems and thus the best linear relationship. The signal entry path is used to apply the rules required for prediction design.
Źródło:
Archives of Electrical Engineering; 2020, 69, 4; 829-840
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
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