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Tytuł:
Free vibration of clamped visco-elastic rectangular plate having bi-direction exponentially thickness variations
Autorzy:
Gupta, A. K.
Khanna, A.
Gupta, D. V.
Powiązania:
https://bibliotekanauki.pl/articles/281741.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
viscoelasticity
clamped rectangular plate
variable thickness
Opis:
Free vibration of a clamped visco-elastic rectangular plate having bi-direction exponentially varying thickness has been analysed on the basis of classical plate theory. For visco-elastic materials, basic elastic and viscous elements are combined. We have assumed the Kelvin model for visco-elasticity, which is a combination of elastic and viscous elements connected in parallel. Here, the elastic element is constituted by a spring and the viscous one is a dashpot. An approximate but quite convenient frequency equation is derived by using the Rayleigh-Ritz technique. Logarithmic decrement, time period and deflection (at two different instant of time) for the first two modes of vibration and for various values of the taper constants and aspect ratio are calculated. Comparison studies have been carried out with bi-linearly thickness variation to establish the accuracy and versatility of the method.
W pracy rozważono problem swobodnych drgań utwierdzonej lepkosprężystej prostokątnej płyty o dwukierunkowo wykładniczo zmiennej grubości na podstawie klasycznej teorii płyt. Uwzględniono lepkosprężyste właściwości materiału płyty, bazując na podstawowych elementach reologicznych. Przyjęto model Kelvina, tj. równoległą kombinację elementu sprężystego i wiskotycznego. Równanie ruchu płyty rozwiązano metodą Rayleigha-Ritza, otrzymując przybliżoną, ale wygodną do analizy postać wyrażenia w dziedzinie częstości. Następnie wyznaczono wartość logarytmicznego dekrementu tłumienia, okresu drgań i ugięcia płyty dla dwóch pierwszych funkcji własnych dla różnych parametrów opisujących zmienną grubość i wymiary zewnętrzne płyty. Wyniki obliczeń przy uwzględnieniu zmiany grubości płyty porównano z dotychczasowymi rezultatami badań w celu potwierdzenia dokładności i uniwersalności metody.
Źródło:
Journal of Theoretical and Applied Mechanics; 2009, 47, 2; 457-471
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Siły wewnętrzne i reakcje podporowe w elementach obudowy prostokątnej
Internal forces and bearing reactions in units of rectangular support
Autorzy:
Rotkegel, M.
Powiązania:
https://bibliotekanauki.pl/articles/340383.pdf
Data publikacji:
2009
Wydawca:
Główny Instytut Górnictwa
Tematy:
obudowa prostokątna
podziałka obudowy prostokątnej
siły wewnętrzne obudowy
rectangular support
rectangular support pitch
internal forces in support
Opis:
W artykule przedstawiono metody obliczania podziałki obudowy prostokątnej. Uwzględniono obudowę prostokątną dwu-, trój- i czterostojakową. Wszystkie ostateczne wzory zostały sprowadzone do najprostszej postaci, co wpływa na skrócenie czasu obliczeń. Przy znanej wartości ciśnienia górotworu, dobór odpowiedniego rozstawu odrzwi zajmuje zaledwie kilka minut.
In the paper, method of calculation of rectangular support pitch was presented. Two, triple and four props rectangular support was considered. All final formulas were reduced to the simplest form, what impacts into the shortening of calculations time. At the known value of rockmass pressure, selection of suitable spacing of frames takes only a few minutes.
Źródło:
Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa; 2009, 1; 51-66
1643-7608
Pojawia się w:
Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculations of the magnetic field of the three-phase 4-conductor line with rectangular busbars
Autorzy:
Kusiak, D.
Piątek, Z.
Szczegielniak, T.
Jabłoński, P.
Powiązania:
https://bibliotekanauki.pl/articles/1395763.pdf
Data publikacji:
2016
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
magnetic field
rectangular busbar
high-current busduct
Opis:
The paper presents the results of the calculations of the magnetic field for the both shielded and non-shielded 3-phase MR 250 busbar manufactured by Elektromontaż 2 in Katowice, Poland. The busbar magnetic field has been determined by the following methods: analytical method for non–shielded busbar without taking into account the skin and proximity effects, analytical–numerical method based on integral equations, two-dimensional method of finite elements with the use of the commercial FEMM software, measurement method on a test stand. The measurements were performed with the use of a special non-directional magnetic field meter. A satisfactory compliance of the calculations has been obtained.
Źródło:
Computer Applications in Electrical Engineering; 2016, 14; 25-38
1508-4248
Pojawia się w:
Computer Applications in Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza drgań płyty prostokątnej z naklejonymi elementami piezoelektrycznymi
Rectangular plate vibration analysis with bonded piezoelectric elements
Autorzy:
Szmidt, M.
Powiązania:
https://bibliotekanauki.pl/articles/213708.pdf
Data publikacji:
2008
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
drgania płyty prostokątnej
elementy piezoelektryczne
rectangular plate vibration
Opis:
W pierwszych punktach pracy przeanalizowane są drgania aluminiowej prostokqtnej płyty, pobudzonej do drgń przez symulujące hałas lotniczy jednorodne ciśnienie akustyczne. Wykorzystana jest teoria plyt Kirchhoffa. Przyjęte jest podparcie przegubowe wszystkich brzegów płyty. Wychodząc od równania drgań płyty tworzone są kolejne, coraz bardziej złożone modele drgań uwzględniające wiskotyczne tłumienie w materiale płyty, a także wymuszenie kinematyczne na dwóch jej brzegach. Następnie zbadane są drgania jakie wzbudza naklejony na środku płyty prostokątny piezoaktuator pobudzany sinusoidalnie zmiennym napięciem. Do opisu obciążenia pochodzącego od piezoelementu wykorzystana jest teoria dystrybucji. Masa piezoelementu oraz wpływ warstwy kleju o skończonej sztywności na ścinanie są pominiete. Porównana jest zarówno postać drgań jak i wartość skuteczna prędkości drgań poprzecznych punktów płyty, pobudzanej ciśnieniem akustycznym oraz sterowanym piezoelementem. Zbadana jest także dynamika płyty z piezoaktuatorem wytrąconym ze stanu zerowych naprężeń, poprzez gwałtowne przyłożenie niezerowego napięcia. Do rozwiązania równań drgań wykorzystana jest metoda rozdzielenia zmiennych Fouriera. Przeprowadzane analizy pozwalają wysnuć wnioski co do słuszności koncepcji aktywnego tłumienia drgań poszycia kadłuba samolotu w celu obniżenia poziomu hałasu w kabinie. Niniejsza praca stanowi merytoryczny wstęp do projektu, mającego na celu opracowanie i realizację koncepcji aktywno-pasywnego tfumienia hałasu w kabinach niewielkich samolotów z napedem śmigłowym.
The vibration of a rectangular aluminium plate excited by the homogenous acoustic pressure simulating aircraft engine noise are studied. The Kirchhoff plate is assumed to be simply supported on all edges. Starting from the plate vibration equation, there are made more and more sophisticated plate vibration models considering viscous damping in the material and kinematic excitation on one pair of plate boundaries. Vibrations excited by sinusoidal voltage applied to piezoactuator bonded to the center of the plate are studied. Partial differential equation of plate motion is solved by means of the Fourier separation variable method. The piezoelement loading is written by means of a distributed theory. The piezoelement mass and the influence of a bonding layer with a finite shear stiffnes are neglected. The characteristics of the vibrations and the root mean square of a vibration velocity excited by acoustic pressure and controlled piezoelement are compared. The dynamics of the plate with the piezoactuator equilibrium disturbed by the rapidly applied voltage is examined. Obtained results lead to the conclusions reffering to the active damping of a fuselage skin plating vibrations concept of soundproofing. The paper is a preliminary work to the project of developing and realization of the active-passive internal noise muffling concept in the small propeller aircrafts.
Źródło:
Prace Instytutu Lotnictwa; 2008, 1(192); 1-57
0509-6669
2300-5408
Pojawia się w:
Prace Instytutu Lotnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pre-designing of a mechatronic system using an analytical approach with Dymola
Autorzy:
Hamza, G.
Choley, J.-Y.
Hammadi, M.
Riviere, A.
Barkallah, M.
Louati, J.
Haddar, M.
Powiązania:
https://bibliotekanauki.pl/articles/281893.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
pre-dimensioning
Dymola
analytical method
vibration
rectangular plate
Opis:
This paper presents a pre-dimensioning method applied to a mechatronic system and regarding the vibrational aspect, through a simple modeling process in Dymola environment. We study the vibration transmission between dynamic exciters (motors) and receivers (electronic cards) which are located on a simply supported rectangular plate, using an analytical approach. This new method will allow us to perform representative and robust modeling and simulation. The solution for this issue would be a pre-sizing and pre-positioning procedure. It aims to determine a set of possible technical solutions and principal characteristics before the definitive choice of components and precise sizing of the system. The presented method predicts also behaviour of the mechatronic system. In order to validate the model with respect to the finite element method, selected simulation results are presented.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 3; 697-710
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes of tourism in Croatia in the post-socialist period
Autorzy:
Wiskulski, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/1199408.pdf
Data publikacji:
2019-09-30
Wydawca:
Uniwersytet Gdański. Instytut Geografii
Tematy:
Croatia
Perkal Synthetic Indicator
Rectangular Coordinate System
tourism
Opis:
21 years of transformation in the tourist function in the territory of Croatia has been summarized in the article. This area has come a long way from the region that was an integral part of Yugoslavia, through the area of warfare related to the civil war to one of the fastest growing tourist destinations in the world. The number of tourists has more than tripled, with an increase from 57% to 1830% in individual counties of Croatia during the analyzed period. At the same time, there was a disproportionately low increase in capacity of accommodation base across the country at the level of 76%. This increase took values from 20% to 350% in extreme districts.
Źródło:
Journal of Geography, Politics and Society; 2019, 9, 3; 14-22
2084-0497
2451-2249
Pojawia się w:
Journal of Geography, Politics and Society
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Buckling analysis of three-layered rectangular plate with piezoelectric layers
Autorzy:
Yaghoobi, H.
Rajabi, I
Powiązania:
https://bibliotekanauki.pl/articles/282015.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
three-layered rectangular plate
piezoelectric
critical buckling load
Opis:
This paper employs an analytical method to analyze the buckling of piezoelectric coupled plates with different boundary conditions on the basis of the first order shear deformation plate theory. The structure is composed of a host isotropic plate and two bonded piezo electric layers. Convergence study is performed in order to verify the numerical stability of the presented method. Also, the present analysis is validated by comparing the results with those in the literature, and then the critical buckling load of the piezoelectric coupled plates is presented in tabular and graphical forms for different plate aspect ratios, thickness of the piezoelectric, actuator voltage and boundary conditions.
Źródło:
Journal of Theoretical and Applied Mechanics; 2013, 51, 4; 813-826
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parametric comparison of rectangular and circular pontoons performance as floating breakwater numerically
Autorzy:
Tabatabaei, S. M. R.
Zeraatgar, H.
Powiązania:
https://bibliotekanauki.pl/articles/260165.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
Floating Breakwater
transmission coefficient
circular section
rectangular section
Opis:
Rectangular and circular pontoons are one of the most widely cross-sections used as floating breakwaters (FB). Although, there are several articles on comparison of behavior of rectangular and circular floating breakwaters however, the Authors try to show some details of difference between these two types where they have not been addressed before. To do so, transmission coefficient (Ct), as a measure of merit, of similar rectangular and circular sections is numerically compared. A computer code is developed for two-dimensional hydrodynamic analysis of floating breakwater based on diffraction theory in frequency domain in regular waves with any configuration of mooring line. The numerical method is the finite element method and validated by comparing with experimental and numerical results. Three types of rectangular sections are defined equivalent to circular section and a numerical comparison is made between 100 similar sections. The Ct versus wave frequency has been considered in detail and three new points called LMinF, LMaxF and LMaxCt are introduced. It has been shown that LMinF and LMaxF of circular section are greater and LMaxCt is much smaller than equivalent rectangular section. The LMaxCt of both sections are very dependent to new nondimensional parameter B/D (Breadth/Draft). Although, rectangular sections are more common for floating breakwater, however the results of this study show that possibility of using circular sections must be also considered.
Źródło:
Polish Maritime Research; 2018, S 1; 94-103
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cullis-Radić determinant of a rectangular matrix which has a number of identical columns
Autorzy:
Makarewicz, Anna
Pikuta, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/1395917.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
Determinant
rectangular matrix
Cullis-Radić determinant
repeated columns
Opis:
In this paper we present how identical columns affect the Cullis-Radić determinant of an \(m\times n\) matrix, where \(m\leq n\).
Źródło:
Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica; 2020, 74, 2
0365-1029
2083-7402
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tunelowanie o przekroju prostokątnym
Rectangular tunnels construction
Autorzy:
Kuliczkowski, A.
Fujawa, M.
Powiązania:
https://bibliotekanauki.pl/articles/144166.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Komunikacji Rzeczpospolitej Polskiej
Tematy:
tunele
budowa
przekrój prostokątny
tunnels
construction
rectangular shape
Opis:
Przedstawiono metody budowy tuneli o przekroju prostokątnym. Skoncentrowano się na metodach bezwykopowych z uwagi na nieutrudnianie ruchu ulicznego. Przeanalizowano wybrane przykłady urządzeń tarczowych o przekrojach prostokątnych (wraz z kwadratowymi), a także zbliżonych do prostokątnych oraz zaprezentowano przykładowe realizacje tuneli z wykorzystaniem opisanych urządzeń.
The available no-dig methods of rectangular tunnels construction were presented. The authors focused on trenchless technologies as they do not disturb on ground traffic. Chosen examples of rectangular shield machines (including the square ones) as well as quasi rectangular ones were analyzed. The examples of tunnels built using described machines were also presented.
Źródło:
Drogownictwo; 2014, 7-8; 258-265
0012-6357
Pojawia się w:
Drogownictwo
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exponential temperature effect on frequencies of a rectangular plate of non-linear varying thickness: a quintic spline technique
Autorzy:
Gupta, A. K.
Mamta, J.
Powiązania:
https://bibliotekanauki.pl/articles/949230.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
exponentially temperature
non-linear
thickness variation
vibration
rectangular plate
Opis:
The differential equation governing the transverse motion of an elastic rectangular plate of non-linear thickness variation with thermal gradient has been analyzed on the basis of classi- cal plate theory. Following Levy’s approach, i.e. the two parallel edges are simply supported, the fourth-order differential equation governing the motion of such plates of non-linear vary- ing thickness in one direction with exponentially temperature distribution has been solved by using the quintic splines interpolation technique for two different combinations of clamped and simply supported boundary conditions at the other two edges. An algorithm for com- puting the solution of this differential equation is presented for the case of equal intervals. The effect of thermal gradient together with taper constants on the natural frequencies of vibration is illustrated for the first three modes of vibration.
Źródło:
Journal of Theoretical and Applied Mechanics; 2014, 52, 1; 15-24
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The rectangular two-phase closed thermosyphon: A case study of two-phase internal flow patterns behaviour for heat performance
Autorzy:
Chompookham, Teerapat
Sichamnan, Surachet
Bhuwakietkumjohn, Nipon
Parametthanuwat, Thanya
Powiązania:
https://bibliotekanauki.pl/articles/240618.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
internal flow
flow pattern
rectangular two-phase closed thermosyphon
Opis:
This research explored different types of two-phase flow patterns that influenced heat transfer rate by assessing rectangular two-phase closed thermosyphon (RTPCT) made from glass with the sides of equal length of 25.2 mm, aspect ratio 5 and 20, evaporation temperature of 50, 70, and 90°C, working substance addition rate of 50% by volume of evaporator, and water inlet temperature at condensation of 20°C. Upon testing with aspect ratios 5, three flow patterns emerged which were: bubble flow, slug flow and churn flow respectively. As per the aspect ratio 20, four flow patterns were discovered which were: bubble flow, slug flow, churn flow and annular flow, respectively. Aspect ratio 5 pertains characteristic which resulted in a shorter evaporation rate of the RTPCT than that of the aspect ratio 20, thus, a shorter flow distance from the evaporator section to heat releaser was observed. Therefore, flow patterns at aspect ratio 5 exhibited a faster flow velocity than that of the aspect ratio 20. Furthermore, changes of flow pattern to the one that is important for heat transfer rate can be easily achieved. Churn flow was the most important type of the flow for heat transfer, followed by slug flow. Moreover, with aspect ratio 20, annular flow was the most important flow for the heat transfer, followed by churn flow, respectively. Throughout the test, average heat flux as obtained from the aspect ratio 5 were 1.51 and 0.74 kW/m2 which were higher than those of the aspect ratio 20. The highest heat flux at the operating temperature of the evaporator section was 90°C, which was equivalent to 2.60 and 1.52 kW/m2, respectively.
Źródło:
Archives of Thermodynamics; 2020, 41, 3; 223-254
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inclination angle implications for fluid flow and mixed convection in complex geometry enclosure-meshless numerical analyses
Autorzy:
Najafi, M.
Nikfar, M.
Arefmanesh, A.
Powiązania:
https://bibliotekanauki.pl/articles/279898.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
meshless
Petrov-Galerkin
mixed convection
rectangular cavity
wavy wall
Opis:
The meshless local Petrov-Galerkin (MLPG) method is extended to analyze the mixed convection and fluid flow in an inclined two-dimensional lid-driven cavity. The enclosure considered comprises two insulated vertical walls and a wavy bottom wall which is subjected to a higher constant temperature than its top counterpart, the sliding lid. For the proposed scheme, the stream function formulation with a weighting function of unity is employed. The simulation results reveal that the local Nusselt number increases with a clockwise increase in the inclination angle. Also, a decrease in the aspect ratio results in an increase in the hot wavy wall average Nusselt number.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 3; 519-530
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vibration frequencies of a rectangular plate with linear variation in thickness and circular variation in Poisson’s ratio
Autorzy:
Sharma, Amit
Powiązania:
https://bibliotekanauki.pl/articles/280855.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
rectangular plate
circular variation
linear variation
Poisson’s ratio
Opis:
The frequency for the first two modes of vibration of a nonhomogeneous tapered rectangular plate is calculated under a bi linear (i.e., linear along both the axes) temperature field. For consideration of the nonhomogeneous material, the author assumed circular variation in Poisson’s ratio. Tapering in the plate is assumed to be linear in one direction. The results are calculated for different values of plate parameters and presented with the help of graphs. Comparison of the results is also given, to support the results of the present study.
Źródło:
Journal of Theoretical and Applied Mechanics; 2019, 57, 3; 605-615
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coloring rectangular blocks in 3-space
Autorzy:
Magnant, Colton
Martin, Daniel
Powiązania:
https://bibliotekanauki.pl/articles/743845.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
chromatic number
channel assignment problem
3 dimensional rectangular blocks
Opis:
If rooms in an office building are allowed to be any rectangular solid, how many colors does it take to paint any configuration of rooms so that no two rooms sharing a wall or ceiling/floor get the same color? In this work, we provide a new construction which shows this number can be arbitrarily large.
Źródło:
Discussiones Mathematicae Graph Theory; 2011, 31, 1; 161-170
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free vibrational analysis of rectangular ducts with different joint conditions
Autorzy:
Jade, N.
Venkatesham, B.
Powiązania:
https://bibliotekanauki.pl/articles/279956.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
rectangular duct
duct joint
experimental modal analysis
modal assurance criteria
Opis:
Rectangular ducts are fabricated using thin sheets of a metal with different joint conditions. Due to the presence of these joints, ducts deviate from their assumptive ideal shapes. The objective of the present work is to study the effect of different joint conditions and wall thickness on dynamic characteristics of the ducts. Experimental Modal Analysis (EMA) is performed on three rectangular ducts of different joint types. Numerical Modal Analysis (NMA) is also performed by considering that the ducts are of ideal rectangular shape (without joint condition). Correlation analysis is performed between EMA and NMA in terms of Modal Assurance Criteria (MAC), Relative Frequency Difference (RFD) plots and auto-MAC. It is observed that natural frequencies are in good agreement but there is a discrepancy in mode shapes.
Źródło:
Journal of Theoretical and Applied Mechanics; 2018, 56, 4; 1069-1081
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling method of dynamic characteristics of marine thin-walled structure
Autorzy:
Doan, Do Van
Szeleziński, Adam
Murawski, Lech
Muc, Adam
Powiązania:
https://bibliotekanauki.pl/articles/245078.pdf
Data publikacji:
2019
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
thin-walled structure
vibration
FEM
rectangular plate
Patran-Nastran software
Opis:
Thin-walled structures are very popular in industries, especially in the field of shipbuilding. There are many types of equipment and structures of ships, which are made up of thin-walled structures such as hull, deck and superstructure. Therefore, the analysis and understanding of the static and dynamic characteristics of a thin-walled structure are very important. In this article, we focus on vibration analysis of a typical thin-walled structurerectangular plate, a basic structure of the hull. Vibration analysis of a rectangular thin plate is conducted by two methods: numerical modelling method of the finite element on Patran-Nastran software platform and experimental method implemented in the laboratory of Gdynia Maritime University. Thin rectangular plate is fixed one end by four clamping plates and is modelled with finite elements and different meshing densities. The numerical model of thin rectangular plate is divided into four cases. Case 1, thin rectangular plate, and clamping plates are modelled with two-dimensional elements. Case 2, the rectangular thin plate is modelled with two-dimensional elements; the clamping plates are modelled with three-dimensional elements. Case 3, both the rectangular thin plate and clamping plates are modelled with three-dimensional elements. Case 4, the rectangular thin plate, and clamping plates are modelled with three-dimensional elements with larger mesh density to increase the accuracy of the calculation results. After that, the results of vibration analysis according to the numerical modelling method on Patran-Nastran software platform for these cases were compared with the measurement results. From there, assess the accuracy of analysis results of selected numerical model methods and the ability to widely apply this numerical model method to other marine structures
Źródło:
Journal of KONES; 2019, 26, 4; 39-46
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An easy procedure to transform the ratio of two polynomials of first degree into Michaelis-Menten-type equations. Application to the ordered Uni Bi enzyme mechanism.
Autorzy:
Fontes, Rui
Ribeiro, João
Sillero, Antonio
Powiązania:
https://bibliotekanauki.pl/articles/1044439.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
rectangular hyperbolas
enzyme inhibition
enzyme equations
enzyme kinetics
graphical presentations
Opis:
It is not always clear that some equations affected by complicated factors can, actually, be interpreted as a ratio of two polynomials of first degree and so that they can be, in general, represented by rectangular hyperbolas. In this paper we present an easy procedure to rearrange those equations into Michaelis-Menten-type equations and so to make the aspects of these rectangular hyperbolas more clear, particularly for researchers familiar with general biochemistry. As an example, the method is applied to transform the classical rate equation of the Cleland×s Ordered Uni Bi enzyme mechanism.
Źródło:
Acta Biochimica Polonica; 2000, 47, 1; 259-268
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nierównomierność rozpływu mieszaniny dwufazowej gaz - ciecz w układzie minikanałów współpracujących równolegle
Two phase gas- liquid flow maldistribution in a system of parallel minichannels
Autorzy:
Miłaszewicz, B.
Ulbrich, R.
Powiązania:
https://bibliotekanauki.pl/articles/2071126.pdf
Data publikacji:
2010
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
minikanał prostokątny
równomierność przepływu
głowica
rectangular minichannel
flow uniformity
header
Opis:
Nierównomierna dystrybucja faz do poszczególnych kanałów jest powszechnym zjawiskiem i powoduje istotne obniżenie sprawności aparatów wykorzystujących przepływ w kanałach równoległych. Jest to zjawisko skomplikowane, słabo poznane w zakresie badań w minikanałach. W artykule przedstawiono badania przepływu opadającego mieszaniny dwufazowej do układu ośmiu minikanałów. Zastosowano dwa typy głowicy różniące się geometrią. Wykazano istotne znaczenie zarówno geometrii głowicy jak i strumieni doprowadzanych faz.
Phase maldistribution to particular channels is common phenomena and causes significant efficiency reduction of devices using parallel flow. It is very complicated and poorly examined phenomena in minichannels. Research results of two-phase downward flow of mixture to the system of eight parallel minichannels are presented in the paper. Two kinds of header of various geometry was employed. It was proved that both geometry and volumetric flow rate of gas and liquid had a substantial significance on flow uniformity.
Źródło:
Inżynieria i Aparatura Chemiczna; 2010, 3; 69-70
0368-0827
Pojawia się w:
Inżynieria i Aparatura Chemiczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A modified Fourier-Ritz method for free vibration of rectangular plates with elastic constrains
Autorzy:
Wu, Tao
Chen, Zhao Bo
Qu, Jian Jun
Powiązania:
https://bibliotekanauki.pl/articles/2086961.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
modified Fourier-Ritz method
rectangular plate
free vibration
boundary conditions
Opis:
In this paper, a modified Fourier-Ritz method is used to study free vibration of a rectangular plate with a set of simply supported opposite sides and another set of arbitrary elastic constraints. The influence of different elastic constraint stiffness values on the modal response of the rectangular plate is also analyzed. In order to avoid that the displacement function of the rectangular plate calculated by the traditional method and its derivative may be discontinuous or non-derivable at the boundary, the displacement function is expressed in the form of the sum of standard cosine series and a periodic polynomial function. Compared with the sine series expansion, the convergence of the result is enhanced. Several sets of numerical examples with different boundary conditions are given in the article, the data shows that the results calculated by this method have good accuracy and fast convergence. In addition, this paper also analyzes the boundary conditions and discusses the influence of different spring stiffness values on the setting of boundary conditions. The results can be applied to the setting of general boundary conditions and the study of vibration control of rectangular plates.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 1; 77--89
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Dual-band Circularly-polarized Printed Monopole Antenna for Wi-Fi and WiMAX Applications
Autorzy:
Lwin, Zaw Myo
Aye, Thae Su
Powiązania:
https://bibliotekanauki.pl/articles/307652.pdf
Data publikacji:
2019
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
circular polarization
dual-band antenna
printed monopole antenna
rectangular slit
Opis:
This paper presents a rectangular-shaped printed monopole antenna with circular polarization for Wi-Fi (2.4–2.484 GHz) and WiMAX (3.3-3.7 GHz) bands. The antenna relies on asymmetric arrangement of the patch with respect to the microstrip feed, in order to generate circular polarization. Dual-band (Wi-Fi and WiMAX) operation is enabled by inserting a slit in the corner of the ground plane. Simulation results show a bandwidth increase of 15.9% (2.2–2.58 GHz) for Wi-Fi, and of 24.16% (3.13–3.99 GHz) for WiMAX applications. Furthermore, beamwidths at the axial ratio of 3 dB equal 48˚ and 51˚ for the x-z plane and y-z planes, respectively.
Źródło:
Journal of Telecommunications and Information Technology; 2019, 4; 50-54
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strength of a metal seven-layer rectangular plate with trapezoidal corrugated cores
Autorzy:
Magnucka-Blandzi, E.
Walczak, Z.
Wittenbeck, L.
Rodak, M.
Powiązania:
https://bibliotekanauki.pl/articles/280482.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
rectangular layered plate
corrugated cores
hypothesis of deformation
deflection
stresses
Opis:
The subject of analytical and numerical investigations in this paper is a metal seven-layer rectangular plate with a trapezoidal corrugated main core and two trapezoidal corrugated cores of faces. The hypothesis of deformation of the normal to the middle surface of the plate after bending and field of displacements is formulated. The plate is simply supported on all its edges and subjected to a uniform pressure. Equations of equilibrium are derived based on the theorem of minimum total potential energy and are solved with the use of the Galerkin method. The influence of the trapezoidal corrugation pitch of the cores on the deflection and the equivalent stress is analysed.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 2; 433-446
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental tests for the occurence of convective heat transfer within the bed of rectangular steel profiles
Autorzy:
Wyczółkowski, R.
Musiał, D.
Powiązania:
https://bibliotekanauki.pl/articles/239990.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
konwekcja swobodna
liczbia Rayleigha
free convection
Rayleigh number
rectangular sections
Opis:
The paper describes tests intended to examine the occurrence of natural convection within the space occupied by 40x20 mm rectangular steel sections. Within these tests the bed of four layers of section was heated by the electric palate heater. Depending on the manner in which the heater was positioned, the tests were divided into two series. In the case of heating from above, the heat flowing through the bed is transferred only by conduction and radiation. When heating the bed from below, in addition to conduction and radiation, also a convective heat transfer will occur. Should this be the case, it will result in the intensification of the heat exchange. The results of measurements carried out have not demonstrated that the occurrence of any possible natural convection would influence the development of a temperature field in this type of charge.
Źródło:
Archives of Thermodynamics; 2012, 33, 3; 89-100
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic response analysis of a thin-walled rectangular plate subjected to thermoacoustic loadings
Autorzy:
Dang, Zhigao
Mao, Zhaoyong
Powiązania:
https://bibliotekanauki.pl/articles/240521.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
thermoacoustic loadings
buckling
dynamic response
modal snap-through
rectangular plate
Opis:
For thin-walled structures invariably exposed to thermal and noise environment, their dynamic response is an extreme concern in the design of the component of advanced hypersonic aircraft. To address the problem, three theoretical models are established with three typical graded thermal distributions considered. By introducing the thermal moment, membrane forces and acoustic loadings into the vibration equation of plate, the governing equation is derived and it is solved combined with boundary conditions of the plate, the modal function and velocity compatibility equations at the fluid-structure coupling surface. The accuracy of the theoretical predictions is checked against finite element results with good agreement achieved. The results show that not the physical parameters with variation of temperature but the thermal moments and membrane forces, cause the buckling phenomenon. It is noted that buckling phenomenon occurs not only in uniform temperature field but also in graded temperature distribution filed. The mechanism analysis about modal snap-through and losing phenomenon indicates that thermoacoustic loadings will affect the stiffness matrix and mass matrix of structure. With the increase of temperature, the lower modes of the plate are lost, the higher modes appear in advance, and the losing phenomenon occurs in accordance with the order.
Źródło:
Archives of Thermodynamics; 2020, 41, 1; 151-174
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free vibration analysis of isotropic rectangular plates on Winkler foundation using differential transform method
Autorzy:
Kumar, Y.
Powiązania:
https://bibliotekanauki.pl/articles/265747.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
metoda transformacji
izotropia
differential transform method
isotropic
rectangular
Winkler foundation
Opis:
A differential transform method (DTM) is used to analyze free transverse vibrations of isotropic rectangular plates resting on a Winkler foundation. Two opposite edges of the plates are assumed to be simply supported. This semi-numerical-analytical technique converts the governing differential equation and boundary conditions into algebraic equations. Characteristic equations are obtained for three combinations of clamped, simply supported and free edge conditions on the other two edges, keeping one of them to be simply supported. Numerical results show the robustness and fast convergence of the method. Correctness of the results is shown by comparing with those obtained using other methods.
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 2; 589-597
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
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