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Tytuł:
Investigation into the production flaws in thin solid carbon laminates by using the ultrasonic phased array method
Autorzy:
Pil'a, J.
Ojciec, M.
Balcerzak, T.
Powiązania:
https://bibliotekanauki.pl/articles/198183.pdf
Data publikacji:
2018
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
carbon
composites
CFRP
non-destructive testing
Phased Array
ultrasonic phased array
węgiel
kompozyty
badania nieniszczące
Opis:
Composites are used in a wide variety of markets, including the aerospace, architecture, automotive and military sectors. Along with the increased use of composites, multiple non-destructive testing (NDT) methods have been further developed specifically for inspecting them. Among them, one can single out ultrasonic phased arrays. Research described in this article focuses on the use of ultrasonic PAs for production flaw investigations into an aileron. The examined part was made of up to 16 layers of BAER 3068 epoxy carbon prepreg. The investigation was carried out by using the tap test, conventional ultrasonic measurement and phased array methods. The phased array method allowed us to thoroughly check the affected specimen and confirm the presence of a production flaw in the form of epoxy resin build-up. The results show how effective this method can be and emphasize its advantages over traditional ultrasonic inspections.
Źródło:
Zeszyty Naukowe. Transport / Politechnika Śląska; 2018, 101; 141-148
0209-3324
2450-1549
Pojawia się w:
Zeszyty Naukowe. Transport / Politechnika Śląska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of Lack of Fusion and Incomplete Penetration in Butt Weld Joint by Ultrasonic Phased Array Method and X-Ray Method
Autorzy:
Koňár, R.
Mičian, M.
Boháčik, M.
Gucwa, M.
Powiązania:
https://bibliotekanauki.pl/articles/357016.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
internal defects
butt weld joint
nondestructive testing
lack of fusion
incomplete penetration
Opis:
The main goal of the article is to identify artificially created defects like lack of fusion and incomplete penetration in buttweld joint using non-destructive volumetric methods. These defects are the most serious defects in welds of steel constructionsfrom the safety point of view. For identification, an ultrasonic phased array technique and a conventional X-ray using digital imaging were used. The theoretical part of the article describes the current state of the given issue and provides basic theoretical knowledge about ultrasonic and X-ray welding tests. In the experimental part, the procedure and results of testing butt weld joint are described by both non-destructive methods. The butt weld joint was made from steel S420MC. Each indication obtained by the ultrasonic and x-ray technique is supplemented by the macrostructure of the weld taken from the indication position. The results of the experimental work mentioned in the article point to the possibility and reliability of the identification of melting defects by selected nondestructive methods in terms of their character and orientation.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 1117-1124
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena uszkodzeń udarowych rur kompozytowych wykonanych metodą nawijania i zaprojektowanych według metody tablicowej
Impact damage research in composite filament-wound tubes designed by array method
Autorzy:
Bobrowska, M.
Barcikowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/213220.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
kompozytowe konstrukcje nawijane
uszkodzenia udarowe
udar balistyczny
metoda tablicowa
metoda nawijania włókna
composite filament-wound structures
impact damage
ballistic impact
array method
filament winding
Opis:
W artykule przedstawiono wyniki badań uszkodzeń będących następstwem udaru wysokiej prędkości w konstrukcjach kompozytowych wytworzonych metodą nawijania włókna na mokro. Przebadano pięć warstwowych rur kompozytowych, ktore zostaty zaprojektowane i wytworzone w taki sposób, aby była możliwa ocena wpływu struktury wzmocnienia - trzech, różnych wzorów mozaikowych - na rozmiar a także na charakter uszkodzeń powstałych w kompozycie na skutek udaru. Wzory mozaikowe dobrano z użyciem metody tablicowej, która pozwoliła uzyskać wiele wzorów mozaikowych różniących się wartością reszty skoku nawijania oraz liczbą przeplotów, będących miejscami koncentracji naprężeń i znacząco wpływających na wytrzymałość kompozytu. Udarność kompozytowych konstrukcji nawijanych badano w zakresie dużych prędkości 140-170 m/s. Trudno jednoznacznie określić, który z wzorów mozaikowych ma największą odporność udarową z zakresu wysokich prędkości.
This work presents results of high velocity impact damage in composite filament-wound structures. The subject of research was five-layered composite pipes that have been designed and manufactured in such way as to be able to assess the effect of reinforcement structure - three different mosaic patterns-on the size and nature of impact damage in the composite. The selection of mosaic pattern was based on an array method. It allows to get a lot of mosaic patterns with different rest of the winding stroke and the number of interlaces, which are places of stress concentration and significantly affect the strength of the composite. Impact strength of the composite filament-wound structures was tested in the range of the high velocity impact of 140-170 m/s. It is difficult to define which mosaic pattern has the highest impact resistance in the field of high velocity impact.
Źródło:
Prace Instytutu Lotnictwa; 2016, 3 (244); 26-40
0509-6669
2300-5408
Pojawia się w:
Prace Instytutu Lotnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pseudorandom number generator based on array probability density function method
Autorzy:
Skórkowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/114341.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
pseudorandom number generator
pseudorandom number
probability density function array
histogram array
Opis:
: The idea of the generation of pseudorandom numbers, forming a population of any demanded distribution of given range, there is presented in the paper. The idea is based on use the pseudorandom uniform number generator and probability density function array or histogram array of the distribution under interest. The generation examples of pseudorandom numbers forming a specified population are shown. First exemplary population is described by triangle, the second by two triangles and third isosceles trapezoid.
Źródło:
Measurement Automation Monitoring; 2016, 62, 11; 371-374
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Blade section profile array lifting surface design method for marine screw propeller blade
Autorzy:
Król, Przemysław
Powiązania:
https://bibliotekanauki.pl/articles/259996.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
marine propeller
lifting surface
blade section profile
design
Opis:
The lifting surface model is widely used in screw propeller design and analysis applications. It serves as a reliable tool for determination of the propeller blade mean line and pitch distribution. The main idea of this application was to determine the blade shape that would satisfy the kinematic boundary condition on its surface with the prescribed bound circulation distribution over it. In this paper a simplified lifting surface method is presented – in which the 3D task for the entire blade is replaced by a set of 2D tasks for subsequent blade section profiles.
Źródło:
Polish Maritime Research; 2019, 4; 134-141
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimized null steering in compact bowtie antenna array using simulation driven Taguchi method
Autorzy:
Kaur, Baljinder
Marwaha, Anupma
Powiązania:
https://bibliotekanauki.pl/articles/221471.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
interference suppression
non-isotropic antenna array
mutual coupling
simulation-controlled
optimization
Taguchi method
Opis:
Ever rising increase in number of wireless services has prompted the use of spatial multiplexing through null steering. Various algorithms provide electronic control of antenna array pattern. Simulation-driven technique further introduces correction in array factor to account for array geometry. Taguchi method is used here to combat interference in practical antenna arrays of non-isotropic elements, by incorporating the effect of antenna element pattern on array pattern control in the optimization algorithm. 4-element rectangular and bowtie patch antenna arrays are considered to validate the effectiveness of Taguchi optimization. The difference in the computed excitations and accuracy of null steering confirms the dependence of beam pattern on element factor and hence eliminates the need for extra computations performed by conventional algorithms based on array factor correction. Taguchi method employs an orthogonal array and converges rapidly to the desired radiation pattern in 25 iterations, thus signifying it to be computationally cost-effective. A higher gain and a significant reduction in side lobe level (SLL) was obtained for the bowtie array. Further, due to feed along parallel edges of the patch, the radiating edges being slanted to form the bow shape results in a significant reduction in the area as compared with the rectangular patch designed to resonate at the same frequency.
Źródło:
Metrology and Measurement Systems; 2020, 27, 1; 3-17
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-resolution Direction of Arrival Estimation Method Based on Sparse Arrays with Minimum Number of Elements
Autorzy:
Mohammed, Jafar Ramadhan
Powiązania:
https://bibliotekanauki.pl/articles/1839475.pdf
Data publikacji:
2021
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
compressed sensing
direction of arrival
DOA
estimation
sparse array
Opis:
Regular fully filled antenna arrays have been widely used in direction of arrival (DOA) estimation. However, practical implementation of these arrays is rather complex and their resolutions are limited to the beamwidth of the array pattern. Therefore, higher resolution and simpler methods are desirable. In this paper, the compressed sensing method is first applied to an initial fully filled array to randomly select the most prominent and effective elements which are used to form the sparse array. To keep the dimension of the sparse array equal to that of the fully filled array, the first and the last elements were excluded from the sparseness process. In addition, some constraints on the sparse spectrum are applied to increase estimation accuracy. The optimization problem is then solved iteratively using the iterative reweighted l1 norm. Finally, a simple searching algorithm is used to detect peaks in the spectrum solution that correspond to the directions of the arriving signals. Compared with the existing scanned beam methods, such as the minimum variance distortionless response (MVDR) technique, and with subspace approaches, such as multiple signal classification (MUSIC) and ESPIRT algorithms, the proposed sparse array method offers better performance even with a lower number of array elements and in severely noisy environments. Effectiveness of the proposed sparse array method is verified via computer simulations.
Źródło:
Journal of Telecommunications and Information Technology; 2021, 1; 8-14
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-resolution Direction of Arrival Estimation Method Based on Sparse Arrays with Minimum Number of Elements
Autorzy:
Mohammed, Jafar Ramadhan
Powiązania:
https://bibliotekanauki.pl/articles/1839489.pdf
Data publikacji:
2021
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
compressed sensing
direction of arrival
DOA
estimation
sparse array
Opis:
Regular fully filled antenna arrays have been widely used in direction of arrival (DOA) estimation. However, practical implementation of these arrays is rather complex and their resolutions are limited to the beamwidth of the array pattern. Therefore, higher resolution and simpler methods are desirable. In this paper, the compressed sensing method is first applied to an initial fully filled array to randomly select the most prominent and effective elements which are used to form the sparse array. To keep the dimension of the sparse array equal to that of the fully filled array, the first and the last elements were excluded from the sparseness process. In addition, some constraints on the sparse spectrum are applied to increase estimation accuracy. The optimization problem is then solved iteratively using the iterative reweighted l1 norm. Finally, a simple searching algorithm is used to detect peaks in the spectrum solution that correspond to the directions of the arriving signals. Compared with the existing scanned beam methods, such as the minimum variance distortionless response (MVDR) technique, and with subspace approaches, such as multiple signal classification (MUSIC) and ESPIRT algorithms, the proposed sparse array method offers better performance even with a lower number of array elements and in severely noisy environments. Effectiveness of the proposed sparse array method is verified via computer simulations.
Źródło:
Journal of Telecommunications and Information Technology; 2021, 1; 8-14
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model of multipath propagation of ultrasonic pulses in soft tissue using divergent beam tomography method
Autorzy:
Borowski, Jędrzej
Opieliński, Krzysztof J.
Powiązania:
https://bibliotekanauki.pl/articles/127791.pdf
Data publikacji:
2019
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
model of multipath propagation of ultrasonic pulses
ultrasonic transducer ring array
divergent wave beam
soft tissue
ultrasound tomography
model wielościeżkowej propagacji impulsów ultradźwiękowych
pierścieniowa głowica ultradźwiękowa
rozbieżna wiązka fali
tkanka miękka
tomografia ultradźwiękowa
Opis:
The paper presents the model of calculating ultrasound waveform beam emitted inside the circular space of ultrasonic transducer ring array and propagated through a biological medium submerged in water. Each elementary transducer emits a burst signal, which then propagates through a medium and is received by a number of transducers on the opposite side of the ring array. The method allows for calculating runtime and amplitude of ultrasonic bursts while traveling from an emitter to a receiver through a specified soft tissue section geometry, having regard to the refraction and attenuation effects and directivity pattern of transducers. The soft tissue section geometry is constructed using circular shapes with given ultrasound speed and attenuation distribution. The elaborated software creates a set of received waveforms for each transmitting transducer. The presented results produced by the software can be used as a basis for further research on inverse problems in ultrasound waveform tomography.
Źródło:
Vibrations in Physical Systems; 2019, 30, 1; 1-8
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The impact of the magnetization direction on the static and dynamic parameters of an electromagnetic linear actuator
Badanie wpływu kierunku magnesowania na własności statyczne i dynamiczne liniowego przetwornika elektromechanicznego
Autorzy:
Just, K.
Piskur, P.
Powiązania:
https://bibliotekanauki.pl/articles/210116.pdf
Data publikacji:
2018
Wydawca:
Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:
modelowanie i symulacja
napęd elektromagnetyczny
metoda elementów skończonych
analiza pola elektromagnetycznego
tablica Halbacha
modelling and simulation
electromagnetic actuator
finite element method
field analysis
Halbach array
Opis:
This paper presents a simulation analysis of the impact of magnetization direction on the static and dynamic parameters of an electromagnetic linear actuator. The simulation analysis computations were completed for three different magnetization configurations of permanent magnets (i.e. axial, radial, and a Halbach array). The finite element method (FEM) was applied which provided a good representation of the properties of actual physical objects. The computations enabled an investigation into and an assessment of the impact of the runner magnetization method on the static and dynamic properties of the drive.
W artykule przedstawiono analizę wpływu kierunku magnesowania magnesów trwałych na charakterystyki statyczne oraz dynamiczne liniowego przetwornika elektromechanicznego. Obliczenia symulacyjne przeprowadzono dla trzech różnych konfiguracji kierunku magnesowania magnesów trwałych (osiowej, promieniowej oraz tzw. tablicy Halbacha). W obliczeniach wykorzystano metodę elementów skończonych (MES), której zastosowanie zapewnia dobre odwzorowanie własności rzeczywistego obiektu. Przeprowadzone obliczenia pozwoliły na zbadanie i ocenę wpływu kierunku magnetyzacji biegnika na własności statyczne oraz dynamiczne napędu.
Źródło:
Biuletyn Wojskowej Akademii Technicznej; 2018, 67, 2; 77-87
1234-5865
Pojawia się w:
Biuletyn Wojskowej Akademii Technicznej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new mutual coupling compensation method for receiving antenna array-based DOA estimation
Autorzy:
Parhizgar, N.
Powiązania:
https://bibliotekanauki.pl/articles/141040.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
antenna array
beamforming
compensation matrix
DOA estimation
mutual coupling
MUSIC algorithm
Opis:
Most receiving antenna arrays suffer from the mutual coupling problem between antenna elements, which can critically influence the performance of the array. In this work, a novel and accurate form of compensation matrix is applied to compensate the mutual coupling in a uniform linear array (ULA). This is achieved by applying a new method based on solving a boundary value problem for the whole ULA. In this method, both self and mutual impedances are exploited in an accurate characterization of mutual impedance matrix which results in a perfect mutual coupling compensation method, and hence a very accurate direction of arrival (DOA) estimation. In the new scheme, the compensation matrix is obtained by using the relationship between measured voltage and theoretical coupled voltage based on the MOM. Numerical results show that using DOA estimation algorithms to the decoupled voltage obtained by using this method leads to an excellent performance of DOA estimation with higher accuracy and resolution.
Źródło:
Archives of Electrical Engineering; 2018, 67, 2; 419--431
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electromagnetic launch system based on a Halbach array configuration
Autorzy:
Gherman, L.
Rotaru, C.
Pearsica, M.
Powiązania:
https://bibliotekanauki.pl/articles/198034.pdf
Data publikacji:
2018
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
Lorentz force
Halbach array
electromagnetic catapult
Finite Element Method
siła Lorentza
tablica Halbacha
katapulta elektromagnetyczna
Metoda Elementów Skończonych
Opis:
The paper analyses a new configuration of an electromagnetic launch system (EMLS) able to accelerate a 1-kg mass projectile at a muzzle velocity of 3,000 m/s with an acceleration length of 10 m. The analyses consist of a mathematical calculation of the value of acceleration force necessary to achieve the project objectives. Based on these results a new configuration of an EMLS is presented. The projectile is accelerated by the Lorentz force where the magnetic field is created by permanent magnets made of neodymium iron boron (NdFeB). The permanent magnets are arranged in a cylindrical Halbach array with a uniform field inside. The copper wire coils have a special design, which produce a large acceleration Lorentz force with a current under 1,000 A. A short comparative0 analysis shows the advantages of this new solution compared with well-known accelerators such as railguns and coilguns. In the next part of the paper, we present the results of a simulation of this configuration with an interactive software package based on the finite element method used to analyse and solve three-dimensional electromagnetic field problems and simulate the movement of the projectile. These results confirm the advantages of this new configuration and open the way to test the system under laboratory conditions. At the end of the paper, conclusions are presented. This new EMLS, based on Halbach array configuration, can be used as a catapult for UAVs, airplanes or missiles, as a mass driver for small satellites or as a gun, which is a better solution than railguns or coilguns.
Źródło:
Zeszyty Naukowe. Transport / Politechnika Śląska; 2018, 101; 59-66
0209-3324
2450-1549
Pojawia się w:
Zeszyty Naukowe. Transport / Politechnika Śląska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The synchrosqueezing method in bearing estimation of stationary signals for passive sonar with towed array
Autorzy:
Czarnecki, K.
Leśniak, W.
Powiązania:
https://bibliotekanauki.pl/articles/332264.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
reassignment method
time-frequency analysis
direction of arrival
Opis:
In this paper a novel method of the bearing estimation in a passive sonar system with a towed array is introduced. The classical approach of the bearing estimation based on the spatial spectrum is extended by using the synchrosqeezing method that is a part of the reassignment method introduced by Kodera et al. The usage of this method leads to the precise bearing estimation. The proposed method requires a relatively small amount of computation, because of possibility of using the FFT algorithm. Moreover, method immunity against AWGN is tested for a selected sonar array having regard to the direction of arrival and the signal frequency.
Źródło:
Hydroacoustics; 2015, 18; 41-46
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of Direct Direction Finding Method with Two-Dimensional Correlative Processing of Spatial Signal
Autorzy:
Tsyporenko, V. V.
Tsyporenko, V. G.
Powiązania:
https://bibliotekanauki.pl/articles/307660.pdf
Data publikacji:
2018
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
antenna array
correlative interferometric
direct method
radio direction finding
Opis:
In this article, the main parameter of the correlative-interferometric direction finding method with twodimensional correlative processing of spatial signal in the aperture of a linear antenna array (AA) is determined as the value of spatial shift within the AA aperture. The corresponding objective function is also formed. Analytical optimization of this parameter is presented and a comparative analysis of analytical calculations based on simulation results is conducted. In the simulation, a range of dependencies of the middle square deviation of estimation of direction on the value of the spatial shift for a signal-to-noise ratio of 0 dB, for minimum 3-sample and 4-sample Blackman-Harris windows of the spectral analysis, is received. The value of the middle square deviation of estimation of direction will be minimal and will equal 0.02 degrees using a minimum 3-sample Blackman-Harris window with the −67 dB level of side lobes. It offers high noise immunity and high accuracy of direction finding.
Źródło:
Journal of Telecommunications and Information Technology; 2018, 4; 46-53
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method of Logical Synthesis of Integrated Circuits in basis K-PLA
Autorzy:
Novikov, S.
Powiązania:
https://bibliotekanauki.pl/articles/92848.pdf
Data publikacji:
2006
Wydawca:
Uniwersytet Przyrodniczo-Humanistyczny w Siedlcach
Tematy:
logical synthesis of circuits
programmable logic array
PLA
Źródło:
Studia Informatica : systems and information technology; 2006, 1(7); 247-253
1731-2264
Pojawia się w:
Studia Informatica : systems and information technology
Dostawca treści:
Biblioteka Nauki
Artykuł
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