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Tytuł:
Analytical study on dynamic response of cantilever flexible retaining wall
Autorzy:
Yang, Xiuzhu
Liu, Xinyuan
Zhao, Shuang
Yu, Jun
Powiązania:
https://bibliotekanauki.pl/articles/27312122.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
analiza sejsmiczna
ścianka wspornikowa
ściana elastyczna
ściana oporowa
mechanika falowa
odpowiedź dynamiczna
rozwiązanie analityczne
seismic analysis
cantilever wall
flexible wall
retaining wall
wave mechanics
dynamic response
analytic solution
Opis:
Based on wave mechanics theory, the dynamic response characteristics of cantilever flexible wall in two-dimensional site are analyzed. The partial derivative of the vibration equation of soil layer is obtained, and the general solution of the volume strain is obtained by the separation of variables method. The obtained solution is substituted back to the soil layer vibration equation to obtain the displacement vibration general solution. Combined with the soil-wall boundary condition and the orthogonality of the trigonometric function, the definite solution of the vibration equation is obtained. The correctness of the solution is verified by comparing the obtained solution with the existing simplified solution and the solution of rigid retaining wall, and the applicable conditions of each simplified solution are pointed out. Through parameter analysis, it is shown that when the excitation frequency is low, the earth pressure on the wall is greatly affected by the soil near the wall. When the excitation frequency is high, the influence of the far-field soil on the earth pressure of the wall gradually increases. The relative stiffness of the wall, the excitation frequency and the soil layer damping factor have a significant effect on the dynamic response of the flexible retaining wall.
Źródło:
Archives of Civil Engineering; 2023, 69, 2; 435--453
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Investigation of the Propagation Characteristics of Surface Transverse Wave Considering Various Quartz Substrate and Electrode Configurations
Autorzy:
Jiang, Chao
Cao, Xiaoli
Yang, Feng
Liu, Zejun
Powiązania:
https://bibliotekanauki.pl/articles/31339822.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
surface transverse wave
STW
interdigital transducer
IDT
finite element analysis
FEA
quartz
Opis:
Featured with a higher velocity, increased power handling capability, and better aging behavior, surface transverse wave (STW) shows more promising prospects than Rayleigh wave nowadays in various sensing applications. The need to design, optimize, and fabricate the related devices motivates the development of modeling and simulation. For this reason, a three-dimensional (3D) finite element (FE) simulation of STW on quartz, considering the crystal cut angle and the electrode effects, is presented in this study. Firstly, we investigated the effects of quartz’s cut angle on the generated waves. Here, the polarized displacements were analyzed to distinguish the wave modes. Secondly, the investigations of the electrode effects on the polarized displacement, phase velocity, and electromechanical coupling factor (K2) were carried out, for which different material and thickness configurations for the electrodes were considered. Thirdly, to examine the excitation conditions of the generated waves, the admittance responses were inspected. The results showed that not only the crystal cut angle but also the density and the acoustic impedance of the interdigital transducer (IDT) material have a strong influence on the excited waves. This article is the first to analyze STWs considering quartz’s cut angle and electrode effect through a 3D FE model. It could provide a helpful and easy way to design, optimize, and fabricate the related surface acoustic wave devices.
Źródło:
Archives of Acoustics; 2023, 48, 3; 403-412
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Waves, Currents and Seabed Level Change in the Port of Gdynia During Extreme Events
Autorzy:
Sapiega, P.
Zalewska, T.
Wochna, A.
Powiązania:
https://bibliotekanauki.pl/articles/24201476.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
gulf of Gdansk
sea wave
hazard analysis
Harbour areas
transport from seabed
hydrodynamic effects
surface current
hydrodynamic model
Opis:
The primary purpose of the paper is to identify port areas most exposed to extreme hydrodynamic conditions (waves, sea currents, seabed level change). The results of modelling using SWAN wave model, MIKE 3D model, and reanalysis and measurement data were used in paper. Swell may exceed 0.8 m for winds exceeding 15 m s-1 from the west and south. During extreme conditions, sea currents can reach 0.4 ms-1 in the outer part of the bay adjacent to the port. Port basins do not show changes in the thickness of the seabed for the given maximum values of bottom currents. The most extensive deposition of the seabed and shore sediments (up to 0.04 m) is found on the Gdynia-Oksywie beach adjacent to the port and the approach fairway at the offshore currents. The outer area of the main breakwater is the most exposed to erosive activity (-0.012 m).
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2023, 17, 3; 515--521
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Structural and Non-Structural Disaster Mitigation Due to Erosion in the Timbulsloko Village, Demak – Central Java
Autorzy:
Sugianto, Denny Nugroho
Widiaratih, Rikha
Widada, Sugeng
Suripin, -
Handayani, Elinna Putri
Cahyaningtyas, Putri
Powiązania:
https://bibliotekanauki.pl/articles/2027833.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
wave damping
permeable breakwater
coastal erosion
Timbulsloko Village
coastal vulnerability analysis
coastal vulnerability index
Opis:
Timbulsloko is a village on the coast of Sayung District, Demak Regency that is severely affected by coastal erosion. The coastal erosion in the Timbulsloko Village is mainly caused by the removal of mangrove areas, which has eliminated the function of the natural breakwater for the coast of the Timbulsloko Village. This study aimed to mitigate the coastal erosion in the form of structural and non-structural protection. Structurally (physically), mitigation is conducted by protecting the coastal area with the application of environmentally friendly coastal protection technology in the form of a Permeable breakwater with a Hybrid Engineering structure. Furthermore, the effectiveness of two different structure segments in damping waves from September 2020 – March 2021 will be measured. In contrast, non-structurally, mitigation is conducted in a non-physical way by analyzing the Coastal Vulnerability Index of Timbulsloko Village based on the parameters of Coastal Typology, Average Tidal Range, Significant Wave Height, Coastal Slope, Coastal Geomorphology, Sea Level Rises, and Shoreline Displacement using the CVI method. The effectiveness of the permeable structure’s wave damping is determined by the initial wave height and transmission wave height measured by the ultrasonic sensor. On the basis of segment differences, the Permeable Breakwater Segment 2 with a distance between bamboo of 0.25 m has better effectiveness than a Permeable Breakwater Segment 1 with a distance between bamboo of 0.5 m. The results of the Coastal Vulnerability Analysis show that the Timbulsloko Village is vulnerable to coastal disasters, especially coastal erosion.
Źródło:
Journal of Ecological Engineering; 2022, 23, 2; 246-254
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrode Mass Loading Effects on Different Piezoelectric Substrates for Saw Delay Lines: A Comparative FEM Analysis
Autorzy:
George, Sheeja P.
Isaac, Johney
Philip, Jakob
Powiązania:
https://bibliotekanauki.pl/articles/2141693.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inter-digital transducers
surface acoustic wave devices
finite element analysis
numerical modelling and simulation
ANSYS
Opis:
Several modelling techniques are currently available to analyse the efficiency of inter-digital transducers (IDTs) fabricated on piezoelectric substrates for producing surface acoustic wave (SAW) devices. Impulse response method, equivalent circuit method, coupling of modes, transmission matrix method, and numerical techniques are some of the popular ones for this. Numerical techniques permit modelling to be carried out with any number of finger electrode pairs with required boundary conditions on any material of interest. In this work, we describe numerical modelling of SAW devices using ANSYS to analyse the effect of mass loading, a major secondary effect of IDTs on the performance of SAW devices. The electrode thickness of the IDT influences the resonance frequency of the SAW delay line. The analysis has been carried out for different electrode materials, aluminium, copper, and gold, for different substrate materials, barium titanate (BaTiO3), X-Y lithium niobate (LiNbO3), lithium tantalate (LiTaO3), and the naturally available quartz. The results are presented and discussed.
Źródło:
Archives of Acoustics; 2022, 47, 1; 89-95
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Probabilistic Liquefaction Analysis Using Standard Penetration Test
Autorzy:
Kamel, Filali
Badreddine, Sbartai
Powiązania:
https://bibliotekanauki.pl/articles/2086777.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
earthquakes
probabilistic hazard analysis
site effects
liquefaction
probability
random variable
wave propagation
Opis:
The Youd etal liquefaction resistance curves developed in 2001 to characterize the cyclic resistance of soil based on SPT test are the most used in the context of the Seed and Idriss simplified procedure as a deterministic model. These curves were developed from a modified database of Seed etal. in 1985 with the assumption that the actual peak shear stress (τd) induced at depth h is always less than that predicted by the simplified procedure (τr) of Seed and Idriss (rd= τd/τr<1). By using a suite of equivalent linear site response analyses to adjust the dynamic and the simplified shear stress at depth h, Filali and Sbartai showed in 2017 that the dynamic peak shear stress for some earthquakes is greater than the simplified peak shear stress (rd>1). As in this case, the assumption of the simplified procedure is not verified, Filali and Sbartai have proposed a corrector factor (RC) in the range where rd>1 to adjust the deformable and rigid body. In this paper, we will present a probabilistic study for the evaluation of the liquefaction potential using a database based on SPT measurement compiled after the Chi-Chi Taiwan earthquake, in which the cyclic stress ratio is evaluated using the proposed corrector factor. The objective of this study is to present a probabilistic shape of the cyclic resistance ratio (CRR) curves based on the original simplified method of Seed and Idriss and the corrected version and a new formulation for computing the probability of liquefaction.
Źródło:
Studia Geotechnica et Mechanica; 2022, 44, 2; 162--174
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wyniki badań testu wytrzymałościowego próbki węgla w świetle badań tomograficznych
Research results of triaxial geomechanical tests of a coal sample in the light of tomographic tests
Autorzy:
Dohnalik, Marek
Krakowska-Madejska, Paulina
Puskarczyk, Edyta
Jelonek, Iwona
Powiązania:
https://bibliotekanauki.pl/articles/2146244.pdf
Data publikacji:
2021
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
rentgenowska tomografia komputerowa
analiza obrazu
test wytrzymałościowy
prędkość fal P i S
computed tomography
image analysis
geomechanical test
P-wave and S-wave velocity
Opis:
Celem niniejszej pracy było sprawdzenie możliwości wykorzystania rentgenowskiej tomografii komputerowej (CT) do obserwacji spękań w badanej próbce węgla przed i po teście geomechanicznym, przeprowadzonym w stanie trójosiowych naprężeń (TRX). W pracy przedstawiono zastosowanie dwóch specjalistycznych technik laboratoryjnych: rentgenowskiej tomografii komputerowej i geomechanicznego trójosiowego testu ściskania. Testy geomechaniczne przeprowadzono za pomocą zestawu pomiarowego TRX-070, GCTS (USA), rejestrując pełną charakterystykę naprężeniowo-odkształceniową. Podczas trójosiowych testów ściskania wykonano też innowacyjne równoczesne pomiary prędkości fal P i S. Próbkę analizowano w dwóch etapach, zdefiniowanych ze względu na stan próbki w obrazie CT: pomiar CT wykonany na nienaruszonej próbce węgla (etap 1) oraz otrzymany po teście zniszczeniowym (etap 2). W pierwszym etapie próbka została zeskanowana w celu odzwierciedlenia początkowego stanu struktury porowej wraz z układem mikropęknięć. Drugi etap reprezentuje próbkę po badaniu geomechanicznym. Dla każdego z etapów przeprowadzono szczegółową analizę struktury porowej. W wyniku proponowanego połączenia wymienionych metod w każdym etapie uzyskano obrazy struktury porów. Próbkę analizowano pod kątem liczby i kierunków propagacji pęknięć i zmian w strukturze porów. Interpretacja jakościowa i ilościowa opierała się na rejestracji zmiany liczby pustek, średnic pęknięć, kątów zapadania i porównaniu struktury porowej pomiędzy stanem początkowym próbki oraz po badaniu geomechanicznym. W 1 etapie (przed testem) największy obiekt (zidentyfikowany jako mikroszczelina) przyjmował objętość powyżej 16 mm3 , po wystawieniu próbki na działanie naprężeń (po zniszczeniu próbki) największy zidentyfikowany obiekt charakteryzował się objętością około 15 razy większą (240 mm3 ). Zidentyfikowane w etapie 2 (po teście wytrzymałościowym) pory są wydłużone (wysokie wartości parametru Elongation), a także nie wykazują znaczącego spłaszczenia (Flatness). Według uzyskanych wyników próbka węgla była podatna na pękanie w określonych kierunkach. Kompleksowe badania wykazały zasadność zastosowania proponowanej metodologii do oceny zmian w strukturze próbki podczas testu wytrzymałościowego.
The study aimed to check the possibility of using computed tomography to observe fractures in coal samples before and after a triaxial compression test (TRX). The paper presents an innovative use of two specialized laboratory techniques: computed tomography and geomechanical triaxial compression test. Geomechanical tests were performed on a TRX-070, GCTS (USA) measuring triaxial system. A full stress-strain characteristic was recorded. Also, during the triaxial compression tests, the P and S wave velocities were measured and dynamic elastic moduli were determined. The results were compared. The sample was analyzed in two stages: CT measurement performed on raw coal sample (stage 1) and after the TRX test which destroyed the sample structure (stage 2). First, the sample was scanned reflecting the initial pores and microcracks system. The final stage represents the sample after the geomechanical test. A detailed pore structure analysis was performed for each of the stages. As a result of the proposed above-mentioned method, images of the pore structure were obtained after each step. The sample was analyzed for crack propagation and changes in the pore structure. The qualitative and quantitative interpretation was based on the determination of the number of voids, crack diameters, collapse angles, and comparison of the pore structure between the initial state of the sample and after the triaxial test. In the first stage (before the test), the largest object (identified as a microcrack) had a volume of approximately 16 mm3 , after the sample was stress-tested (after the sample was destroyed), the largest identified object was about 15 times larger (240 mm3 ). It appeared that the coal sample was prone to fracturing in defined directions. Comprehensive research has demonstrated the legitimacy of using the proposed methodology to evaluate changes in the sample structure during the triaxial test.
Źródło:
Nafta-Gaz; 2021, 77, 1; 3-9
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Complex trapezoid grating for light trapping in thin-film solar cells: super-fine structure
Autorzy:
Fang, Junfei
Gou, Yuchun
Deng, Jianping
Powiązania:
https://bibliotekanauki.pl/articles/1835802.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
light trapping
complex trapezoid grating
rigorous coupled-wave analysis
solar cell
Opis:
The research of the optimal surface structure has attracted considerable interest because of its potential application in light trapping in thin-film solar cells (TFSCs). In this paper, a super-fine structure named complex trapezoid grating is proposed to improve the optical absorption comparing to the conventional simple trapezoid grating in a-Si:H TFSCs. The numerical calculation by utilizing rigorous coupled-wave analysis (RCWA) is conducted to obtain the optical absorption of the structured surface. The results demonstrate that, compared to a planar slab, the optimized-simple trapezoid grating shows 97% enhancement of power conversion efficiency η while the complex trapezoid grating shows 131% enhancement. Obviously, the complex trapezoid grating exhibits a better performance than the simple grating, which is due to the perfect antireflective effect and microcavity resonance effect. The angular response of the optical absorption in a-Si:H TFSCs was also investigated. The results further indicate that it is a better way to select the complex trapezoid grating in improving the optical absorption of silicon-based TFSCs.
Źródło:
Optica Applicata; 2020, 50, 3; 391-400
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and Analysis of Ultrasonic Composite Transducer with a Quarter-wave Taper Transition Horn
Autorzy:
Chen, Tao
Li, Hongbo
Wang, Qihan
Ye, Junpeng
Powiązania:
https://bibliotekanauki.pl/articles/1953535.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
equivalent circuit
composite transducer
quarter-wave
prestressed bolt
finite element analysis
Opis:
Based on the electromechanical equivalent circuit theory, equations related to the resonance frequency and the magnifying coefficient of a quarter-wave vibrator and a quarter-wave taper transition horn were deduced, respectively. A series of 3D models of ultrasonic composite transducers with various conical section length was also established. To reveal the influences of the conical section length and the prestressed bolt on the dynamic characteristics (resonance frequency, amplitude, displacement node, and the maximum equivalent stress) of the models and the design accuracy, finite element (FE) analyses were carried out. The results show that the addition of prestressed bolt increases the resonance frequency and causes the displacement node on the center axis to move towards the small cylindrical section. As the conical section length rises, the increment of resonance frequency reduces and tends to a stable value of 360 Hz while the displacement of the node on the center axis becomes lager and gradually approaches 1.5 mm. Furthermore, the amplitude of the output terminal is stable at 16.18 µm under 220 V peak-topeak (77.8 VRMS) sinusoidal potential excitation. After that, a prototype was fabricated and validated experiments were conducted. The experimental results are consistent with that of theory and simulations. It provides theoretical basis for the design and optimization of small-size, large-amplitude, and high-power composite transducers.
Źródło:
Archives of Acoustics; 2020, 45, 4; 687-697
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat waves and health impact on human in Baghdad
Autorzy:
Hassan, Zahraa M.
Al-Jiboori, Monim H.
Al-Abassi, Hazima M.
Powiązania:
https://bibliotekanauki.pl/articles/118603.pdf
Data publikacji:
2020
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
heat wave
max air temperature
CBC analysis
Baghdad
Opis:
This investigation aim to evaluate the effect of heat wave on health of human, so to achieve this 40 blood samples for person exposed to heat wave were drawn most patients were attend to specialists in hospital laboratories (Medical City, Ibn al-Baladi, Sheikh Zayed, Kadhimiya Educational). The patients aged 10–60 years, male (20) and female (20). CBC analyzes was performed. The result of the presents study recorded a highly signifi cant difference in total (mean and percent) as compared with the normal value of the CBC analyze the result for total (mean and percent) for male the factors CRP, ESR, WBC, PCV, PL (15.5, 43, 11.35, 28.5, 215) respectively (100%, 100%, 100%, 100%, 100%) and the result for total (mean and percent) for female the factors CRP, ESR, WBC, PCV, PL (15, 43.5, 11.35, 31, 220.5) respectively (100%, 100%, 100%, 100%, 100%). According to the result we can conclude that there was a highly significant deferent in mean value for patient compared with the normal value which is the mean cause of hard attack which lead to death. The study is the first of its kind in the Department of Atmospheric Sciences in Iraq.
Źródło:
Scientific Review Engineering and Environmental Sciences; 2020, 29, 2; 212-222
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and Numerical Simulation of the Performance of Acoustic Plenum Chamber of a Marine Gas Turbine Air Supply System
Autorzy:
Rasoulimoghadam, Mehrdad
Kheradmand, Saeid
Powiązania:
https://bibliotekanauki.pl/articles/176931.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
aeroacoustics
large eddy simulation
Lighthill analysis
Ffowcs Williams model
Hawkings model
propagation of wave in duct
Opis:
In the present work, an approach to obtain a design method for the size of the plenum chamber cross-section of a marine gas turbine air supply system has been investigated. Flow in ducts makes noise which is very high in the turbine inlet part because of the large amount of flow. Therefore, this phenomenon should be considered in the design process. A suitable approach to design the duct is proposed (considering acoustic and aerodynamic performance at the same time). In this method, an air supply channel system of the marine gas turbine has been categorized into three sections according to the requirements of the aerodynamic and acoustic; inlet, plenum chamber, and outlet channels with circular cross-sections. The geometrical dimensions of inlet and outlet channels have been determined using the plane waves theory about a channel, in which the effects of flow is ignored. Space limitations of battleships at the dominant frequency have been considered. Then, the optimized size of the mid-channel section, in terms of both aerodynamic and acoustic requirements, using numerical methods and regarding the effects of flow has been calculated. Various 3D turbulent flows inside the plenum chamber have been considered, in which large eddy simulation turbulence model is utilized. Ffowcs, Williams and Hawkings models are used for the sound propagation process based on the Lighthill integral equation. The validity of the simulation has been checked by comparing results (sound pressure level) with experimental data obtained from a chamber. The comparison revealed the acceptable errors for a variety of frequencies. The results disclosed that the performance of channel system aerodynamic decreased when the fraction of plenum chamber cross-section to inlet/outlet channel cross-section increased. With an increase in the cross-section size at first Acoustic performance is improved and then worsen. Six different cases of marine gas turbine air supply system configurations have been presented, in which the limitation of the battleship space is considered. Examining and comparing the acoustic performance of different cases of the air supply channel system, it was found that the amount of sound pressure level, around the air supply channel system, and the high-pressure sound area can move along the air supply channel system. Additionally, deviations from plane waves considering the effects of flow have been inspected in all cases. The reason for this deviation is the effects of the airflow through the channel system and quadrupole sources in the production of sound in the channel system, which causes higher modes.
Źródło:
Archives of Acoustics; 2019, 44, 4; 793-806
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of air velocity at inlet to the intake system on flow parameters
Wpływ prędkości powietrza na wlocie do układu dolotowego na parametry przepływu
Autorzy:
Andrych-Zalewska, Monika
Ambroszko, Wojciech
Wielki, Łukasz
Ziora, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/314576.pdf
Data publikacji:
2019
Wydawca:
Instytut Naukowo-Wydawniczy "SPATIUM"
Tematy:
intake system
CFD analysis
internal combustion engine
modeling
flow
wave phenomena
ANSYS
układ dolotowy
analiza CFD
silnik spalinowy
modelowanie
przepływ
zjawiska falowe
Opis:
The article presents CFD (Computational Fluid Dynamics) analysis of the Ferrari 348 sports car intake system for three variants of air intake speed to the system. The article contains an analysis of the distribution of velocities and static pressures. In addition, local velocity and flow in the filtration chamber were investigated. The influence of air velocity at inlet to the intake system on the abovementioned parameters was determined. The analysis is a prelude to the study of wave phenomena occurring in the intake system, affecting the fill factor of the cylinders. Ansys Fluent software was used for analysis.
W artykule przedstawiono analizę CFD (obliczeniowej dynamiki płynów) układu dolotowego samochodów sportowych Ferrari 348 dla trzech wariantów prędkości wlotu powietrza do układu. Artykuł zawiera analizę rozkładu prędkości i nacisków statycznych. Ponadto zbadano lokalną prędkość i przepływ w komorze filtracyjnej. Określono wpływ prędkości powietrza na wlocie do układu dolotowego na wyżej wymienione parametry. Analiza jest wstępem do badania zjawisk falowych zachodzących w układzie dolotowym, wpływających na współczynnik wypełnienia cylindrów. Do analizy użyto oprogramowania Ansys Fluent.
Źródło:
Autobusy : technika, eksploatacja, systemy transportowe; 2019, 20, 12; 83-87
1509-5878
2450-7725
Pojawia się w:
Autobusy : technika, eksploatacja, systemy transportowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of contact plastic bodies made by aluminium alloy with taking account of micro-roughness surfaces
Autorzy:
Sidun, Paweł
Piwnik, Jan
Powiązania:
https://bibliotekanauki.pl/articles/279880.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
bonding process
FEM analysis
cold welding
wave roughness
Opis:
The following article describes selected aspects of numerical modeling of the process of bonding metal alloys with consideration for micro-roughness. Plastic contact between two deformable bodies is studied within a DEFROM FEM environment. The paper presents selected numerical analysis results for an aluminum alloy. The mathematical model of surface roughness has been created on the basis of the surface real profile. The dependence between the tool lathe angle and the feed has been used to build a numerical model of roughness after completion of the turning process. The article investigates the impact of wave roughness in respect to the size effect and the possibility of cold welding as well as the simplification process of real surface roughness.
Źródło:
Journal of Theoretical and Applied Mechanics; 2019, 57, 1; 73-84
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wybrane aspekty statystycznych analiz modeli ekonometrycznych w propagacji fal radiowych
Selected aspects of statistical analyses of econometric models in radio wave propagation
Autorzy:
Wilk-Jakubowski, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/530894.pdf
Data publikacji:
2019-03-06
Wydawca:
Państwowa Wyższa Szkoła Zawodowa w Raciborzu
Tematy:
statistical analysis
regression indexes
radio wave propagation
Opis:
The article contains review of selected applications of statistical analyses in technical science to present certain information for model parameters (including significance of regression indexes). The main considerations are pertinent to radio wave propagation in satellite systems.
Źródło:
Eunomia – Rozwój Zrównoważony – Sustainable Development; 2018, 2(95); 81-88
1897-2349
2657-5760
Pojawia się w:
Eunomia – Rozwój Zrównoważony – Sustainable Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Experimental Approach to Vibro-Acoustic Study of Beam-Type Structures
Autorzy:
Torres-Romero, J.
Cardenas, W.
Carbajo, J.
Segovia Eulogio, E. G.
Ramis-Soriano, J.
Powiązania:
https://bibliotekanauki.pl/articles/178014.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
beam
modal shape
modal analysis
MLS
Maximum Length Sequence
bending wave propagation velocity
Opis:
In this paper an alternative procedure to vibro-acoustics study of beam-type structures is presented. With this procedure, it is possible to determine the resonant modes, the bending wave propagation velocity through the study of the radiated acoustic field and their temporal evolution in the frequency range selected. As regards the purely experimental aspect, it is worth noting that the exciter device is an actuator similar to is the one employed in distributed modes loudspeakers; the test signal used is a pseudo random sequence, in particular, an MLS (Maximum Length Sequence), facilitates post processing. The study case was applied to two beam-type structures made of a sandstone material called Bateig. The experimental results of the modal response and the bending propagation velocity are compared with well-established analytical solution: Euler-Bernoulli and Timoshenko models, and numerical models: Finite Element Method – FEM, showing a good agreement.
Źródło:
Archives of Acoustics; 2018, 43, 2; 283-295
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
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