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Wyniki wyszukiwania dla: BONE IMPLANT COSSERAT CONTINUUM MICROPOLAR ELASTICITY NUMERICAL SIMULATION FINITE ELEMENT METHOD
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Historical carpentry corner log joints—Numerical analysis within stochastic framework
PublikacjaThe paper presents the results of numerical analysis performed on historical, traditional carpentry corner logjoints of two basic topologies: the short-corner dovetail connection and the saddle notch connection. These types of carpentry joints are commonly used in currently preserved objects of wooden architecture. All connections have been modelled in pinewood, which has been defined in the Finite Element software MSC.Marc/Mentat...
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Progressive failure analysis of laminates in the framework of 6-field nonlinear shell theory
PublikacjaThe paper presents the model of progressive failure analysis of laminates incorporated into the 6-field non-linear shell theory with non-symmetrical strain measures of Cosserat type. Such a theory is specially recommended in the analysis of shells with intersections due to its specific kinematics including the so-called drilling rotation. As a consequence of asymmetry of strain measures, modified laminates failure criteria must...
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Simplified method of simulation of temperature field control system of induction heated calender rolls
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On a method of modelling and simulation of vibration surveillance during ball end milling of flexible details
PublikacjaPraca dotyczy nadzorowania drgań podczas frezowania przedmiotów podatnych smukłym frezem kulistym, z uwzględnieniem zgodności parametrów modelu modalnego. Przeprowadzono analizę dynamiki procesu frezowania. Następnie przedstawiono analizę niestacjonarnego układu drgającego, w którym wyodrębniono podukłady: modalny, strukturalny i łączący. Do minimalizacji poziomu drgań zastosowano dopasowanie prędkości obrotowej wrzeciona do optymalnego...
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On a method of modelling and simulation of vibration surveillance during ball end milling of flexible details
PublikacjaPraca dotyczy nadzorowania drgań podczas frezowania przedmiotów podatnych smukłym frezem kulistym, z uwzględnieniem zgodności parametrów modelu modalnego. Przeprowadzono analizę dynamiki procesu frezowania. Następnie przedstawiono analizę niestacjonarnego układu drgającego, w którym wyodrębniono podukłady: modalny, strukturalny i łączący. Do minimalizacji poziomu drgań zastosowano dopasowanie prędkości obrotowej wrzeciona do optymalnego...
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Numerical modeling and experimental validation of full-scale segment to support design of novel GFRP footbridge
PublikacjaThe paper contains analysis of full-scaled three meters long segment of a novel composite footbridge. Both numerical modeling and experimental validation were performed. Analyzed object is a shell type sandwich channel-like structure made of composite sandwich with GFRP laminates as a skin and PET foam as a core. Several static load schemes were performed including vertical and horizontal forces. In FEM analysis multilayered laminate...
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Experimental Verification of Storm Sewer Transient Flow Simulation
PublikacjaThe paper focuses mainly on laboratory investigations of transient and transcritical flow in a single pipe of a sewer system. The aim of this paper is to present a comparison between pressure values calculated by an improved McCormack scheme and those measured at the hydraulic laboratory of the Gdansk University of Technology, which were observed inside a pipe in an experiment for water flow with pressurization. The analysis proves...
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Behaviour of Fascia-Implant Structure under the Impulse Pressure
PublikacjaW pracy przedstawiono badania eksperymentalne wykonane dla modeli zaoperowanych przepuklin brzusznych poddanych impulsowemu działaniu ciśnienia, analogicznego do kaszlu pooperacyjnego. Zbudowano 57 modeli zgodnie ze sztuką oparacji laparoskopowej, z użyciem powiezi świńskiej, pięciu typów implantów i pięciu rodzajów łączników. Opisano otrzymane wyniki wskazując na mocniejsze i słabsze rozwiązania operacyjne.
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The reactions occuring on the implant as a result of contact with human tissue
PublikacjaObecnosc implantu w ciele czlowieka powoduje liczne, czesto nieprzewidywalne skutki. Powodem takiej sytuacji jest duza roznorodnosc interakcji materialu medycznego z kontaktujaca sie z nim tkanka. Stwierdzenie to dotyczy glownie oddzialywan i skutkow zachodzacych na poziomie molekularnym w poszczegolnych komorkach kontaktujacej sie tkanki.
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Image simulation and annotation for color blinded
PublikacjaIn this paper methods for image simulation as seen by a color blinded and a method for constructing images of perceived color difference are presented. The work is also focused on the interactive color description of an image contents. As a result, the individuals having problems with color discrimination can identify colors in an image.W artykule prezentowane są metody symulacji kolorów w obrazach postrzeganych przez osoby ze...
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Application of the discrete Green's function-based antenna simulations for excitation of the total-field/scattered-field interface in the FDTD method
PublikacjaIn this article, the discrete Green's function formulation of the finite-difference time-domain (DGF-FDTD) method is proposed for simulation of wire antennas irradiating inhomogeneous dielectric scatterers. Surface equivalence theorem in the discrete domain is used to separate the problem into an inhomogeneous domain and a wire antenna that are simulated with the use of FDTD and DGF-FDTD, respectively. Then, the excitation of the...
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Numerical Simulations and Tracer Studies as a Tool to Support Water Circulation Modeling in Breeding Reservoirs
PublikacjaThe article presents a proposal of a method for computer-aided design and analysis of breeding reservoirs in zoos and aquariums. The method applied involves the use of computer simulations of water circulation in breeding pools. A mathematical model of a pool was developed, and a tracer study was carried out. A simplified model of two-dimensional flow in the form of a biharmonic equation for the stream function (converted into...
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A new hyperbolic-polynomial higher-order elasticity theory for mechanics of thick FGM beams with imperfection in the material composition
PublikacjaA drawback to the material composition of thick functionally graded materials (FGM) beams is checked out in this research in conjunction with a novel hyperbolic‐polynomial higher‐order elasticity beam theory (HPET). The proposed beam model consists of a novel shape function for the distribution of shear stress deformation in the transverse coordinate. The beam theory also incorporates the stretching effect to present an indirect...
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Finite-difference time-domain analyses of active cloaking for electrically-large objects
PublikacjaInvisibility cloaking devices constitute a unique and potentially disruptive technology, but only if they can work over broad bandwidths for electrically-large objects. So far, the only known scheme that allows for broadband scattering cancellation from an electrically-large object is based on an active implementation where electric and magnetic sources are deployed over a surface surrounding the object, but whose ‘switching on’...
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Balance errors generated by numerical diffusion in the solution of non-linear open channel flow equations
PublikacjaThe paper concerns the untypical aspect of application of the dissipative numerical methods to solve nonlinear hyperbolic partial differential equations used in open channel hydraulics. It is shown that in some cases the numerical diffusion generated by the applied method of solution produces not only inaccurate solution but as well as a balance error. This error may occur even for an equation written in the conservative form not...
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Combined numerical and experimental approach to determine numerical model of abdominal scaffold
PublikacjaA proper junction of the prosthesis and the abdominal wall is important in successful hernia repair. The number of tacks should be balanced to assure appropriate mesh fixation and not to induce post-operative pain. Numerical simulations help to find this balance. The study is aimed at creating a proper numerical model of a knitted surgical mesh subjected to boundary conditions and load occurring in the abdominal cavity. Continuous,...
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Reinforcement Learning Algorithm and FDTD-based Simulation Applied to Schroeder Diffuser Design Optimization
PublikacjaThe aim of this paper is to propose a novel approach to the algorithmic design of Schroeder acoustic diffusers employing a deep learning optimization algorithm and a fitness function based on a computer simulation of the propagation of acoustic waves. The deep learning method employed for the research is a deep policy gradient algorithm. It is used as a tool for carrying out a sequential optimization process the goal of which is...
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Numerical investigation of multiphase blood flow coupled with lumped parameter model of outflow
PublikacjaPurpose The purpose of this paper is the application of the computational fluid dynamics model simulating the blood flow within the aorta of an eight-year-old patient with Coarctation of Aorta. Design/methodology/approach The numerical model, based on commercial code ANSYS Fluent, was built using the multifluid Euler–Euler approach with the interaction between the phases described by the kinetic theory of granular flow (KTGF). Findings A...
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Quantitative assessment of the influence of tensile softening of concrete in beams under bending by numerical simulations with XFEM and cohesive cracks
PublikacjaResults of the numerical simulations of the size effect phenomenon for concrete in comparison with experimental data are presented. In-plane geometrically similar notched and unnotched beams under three-point bending are analyzed. EXtended Finite Element Method (XFEM) with a cohesive softening law is used. Comprehensive parametric study with the respect to the tensile strength and the initial fracture energy is performed. Sensitivity...
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Comparison the heat load as the results of tests on human subject in a hot environment with the results obtained from numerical simulation
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Numerical Simulation and Experimental Analysis of Thermal Cycles and Phase Transformation Behavior of Laser-Welded Advanced Multiphase Steel
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New trim configurations for laser trimmed thick-film resistors - theoretical analysis, numerical simulation and experimential verification
PublikacjaW pracy przedstawiono nowe podejście do korekcji rezystorów warstwowych polegające na wytwarzaniu dodatkowego kontaktu w celu rozszerzenia zakresu korekcji i uproszczenia projektowania. Ponadto zaprezentowano nową szybką metodę wyznaczania charakterystyk korekcyjnych a także weryfikację eksperymentalną. Przedstawiono wyniki w postaci zakresów korekcji i względnych przyrostów rezystancji w funkcji kształtu dodatkowego kontaktu oraz...
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A method to determine the tightening sequence for standing rigging of a mast
PublikacjaThe article proposes an alternative method to determine the sequence of generation of pre-tension forces in standing rigging of a mast. The proposed approach has been verified on both a virtual simulation experiment and laboratory tests. In this method, the desired tension values are obtained using the influence matrix which allows to calculate the effect of tension change in an individual rope on the tension distribution in the...
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Modelling, Simulation and Optimization of the Wavemaker in a Towing Tank
PublikacjaThe paper analyses the problem of experimental identification (frequency response), modelling and optimization of the towing tank wavemaker in the Scilab/Xcos environment. The experimental identification of the objects (the towing tank wavemaker placed in the hydrodynamic laboratory of the CTO S.A. Ship Design and Research Centre (CTO)) and the implementation of the models in the simulation environment, enable to perform: 1. tuning...
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Efficient Gradient-Based Algorithm with Numerical Derivatives for Expedited Optimization of Multi-Parameter Miniaturized Impedance Matching Transformers
PublikacjaFull-wave electromagnetic (EM) simulation tools have become ubiquitous in the design of microwave components. In some cases, e.g., miniaturized microstrip components, EM analysis is mandatory due to considera¬ble cross-coupling effects that cannot be accounted for otherwise (e.g., by means of equivalent circuits). These effects are particularly pronounced in the structures in¬volving slow-wave compact cells and their numerical...
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On geometry parameterization for simulation-driven design closure of antenna structures
PublikacjaFull-wave electromagnetic (EM) simulation tools have become ubiquitous in antenna design, especially final tuning of geometry parameters. From the reliability standpoint, the recommended realization of EM-driven design is through rigorous numerical optimization. It is a challenging endeavor with the major issues related to the high computational cost of the process, but also the necessity of handling several objectives and constraints...
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Size effect at aggregate level in microCT scans and DEM simulation – Splitting tensile test of concrete
PublikacjaThe paper describes an experimental and numerical study of size effect on concrete cylindrical specimens in splitting tensile test. Own experimental campaign was performed on specimens with 5 various diameters from D = 74, 105, 150, 192 and 250 mm with hardboard loading strips (distributed load according to standard methods) scaled proportionally to the specimen diameter. The crack opening-control system was applied to obtain the...
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On some properties of 2d spectral finite elements in problems of wave propagation
PublikacjaW pracy przedstawiono sformułowanie dwuwymiarowych elementów spektralnych stosowanych w symulacji propagacji fal prowadzonych. Zbadano własności tych elementów pod kątem występowania form pasożytniczych, odporności na dystorsję siatki oraz zbadano wpływ kształtu elementu na krzywe dyspersji
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Virtual spring damper method for nonholonomic robotic swarm self-organization and leader following
PublikacjaIn this paper, we demonstrate a method for self-organization and leader following of nonholonomic robotic swarm based on spring damper mesh. By self-organization of swarm robots we mean the emergence of order in a swarm as the result of interactions among the single robots. In other words the self-organization of swarm robots mimics some natural behavior of social animals like ants among others. The dynamics of two-wheel robot...
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Yade-open DEM: an open-source software using a discrete element methodto simulate granular material
PublikacjaPurpose - YADE-OPEN DEM is an open source software based on the Discrete Element Method which uses object oriented programming techniques. The paper describes the softwarearchitecture.Design/methodology/approach - The DEM chosen uses position, orientation, velocity and angular velocity as independent variables of simulated particles which are subject to explicit leapfrog time-integration scheme (Lagrangian method). The three-dimensional...
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Comparative Analysis of Numerical and Experimental Studies of the Airflow Around the Sample of Urban Development
PublikacjaIn this paper, on the background of a short overview of the recent advances in the field of Environmental Wind Engineering (EWE), a comparison of wind tunnel experiment and numerical simulation for some cases of airflow around an urban layout have been reported. The purpose of the study is quantitative and qualitative comparison of measurements in the wind tunnel as well as numerical simulation using Ansys Fluent software. The...
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Numerical modeling of sound intensity distributions around acoustic transducer
PublikacjaThe aim of this research study is to measure, simulate and compare sound intensity distribution generated by the acoustic transducers of the loudspeaker. The comparison of the gathered data allows for validating the numerical model of the acoustic radiation. An accurate model of a sound source is necessary in mathematical modeling of the sound field distribution near the scattering obstacles. An example of such obstacle is a human...
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Hybridization of the FDTD method with use of the discrete Green's function
PublikacjaIn this contribution, a hybrid technique is presented which combines the finite-difference time-domain (FDTD) method and the discrete Green's function (DGF) formulation of this method. FDTD is a powerful technique for the analysis of complex penetrable objects but its application is not efficient when the computational domain includes many free-space cells. Therefore, the hybrid method was developed which is applicable to complex...
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Numerical solution of threshold problems in epidemics and population dynamics
PublikacjaA new algorithm is proposed for the numerical solution of threshold problems in epidemics and population dynamics. These problems are modeled by the delay-differential equations, where the delay function is unknown and has to be determined from the threshold conditions. The new algorithm is based on embedded pair of continuous Runge–Kutta method of order p = 4 and discrete Runge–Kutta method of order q = 3 which is used for the...
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MAGNETOACOUSTIC HEATING AND STREAMING IN A PLASMA WITH FINITE ELECTRICAL CONDUCTIVITY
PublikacjaNonlinear effects of planar and quasi-planar magnetosound perturbations are discussed. Plasma is assumed to be an ideal gas with a finite electrical conductivity permeated by a magnetic filed orthogonal to the trajectories of gas particles. the excitation of non-wave modes in the filed of intense magnetoacoustic perturbations, i.e., magnetoaciustic heating and streaming, is discussed. The analysis includes a derivation if instantaneous...
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Analiza nieliniowa powłok z materiałów gradientowych w ośrodku mikropolarnym
PublikacjaW pracy zaprezentowano analizę powłok z materiałów gradientowych dla zakresu dużych przemieszczeń. Macierz konstytutywna została wyprowadzona dla elementu powłokowego o 6 stopniach swobody w węźle w teorii ośrodka mikropolarnego. Zaprezentowano wyniki numeryczne dla swobodnie podpartej kwadratowej płyty FGM i porównano je z wynikami z literatury oraz uzyskanymi w programie Abaqus.
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Rigid finite elements and multibody modeling in analyses of a robot shaped elastic/plastic deformations of a beam
PublikacjaDynamics analysis of a system composed of a parallel manipulator and of an elastic beam is presented in the paper. Classic 3RRR parallel manipulator is considered and used to deform the beam. Elasto-plastic deformations are investigated. Rigid-finite-elements technique is employed to deal with dynamics of the beam. A multibody structure is associated with the introduced hybrid system in order to model its dynamics. Idea of the...
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Numerical Investigation of Nuclear Reactor Kinetic and Heat Transfer Fractional Model with Temperature Feedback
PublikacjaAbstract—In the paper, the numerical results concerning the kinetics and proposed heat exchange models in nuclear reactor based on fractional calculus are presented for typical inputs. Two fractional models are proposed and compared with the model based on ordinary derivative. The first fractional model is based on one of the generalized Cattaneo equations. The second one is based on replacing the ordinary to fractional order of...
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Probabilistic sensitivity of limit states of structures. The Monte Carlo simulation
PublikacjaDesign sensitivity deals with the variation of structural response, implicitly dependent on the design variables of the problem. An attempt is made to implement probabilistic notation in engineering sensitivity analysis. The procedure to implement the sensitivity of a structural limit state to a given basic variable is described in the paper - its main idea, depicted by a flowchart and numerical examples of engineering analysis....
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Simulation of the IT Service and Project Management Environment
PublikacjaThe authors of this paper present a simulation of the socio-technical system in which teams of students – regarded as low-maturity organizations – were given a task to utilize the (relatively) mature technologies that support IT project and service management. The experiment consisted of the following phases: teams formation, introduction to technologies used during the simulation, performing a set of reactive and proactive service...
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Survey of modern trends in analysis of continuum damage mechanics
PublikacjaW artykule dokonano szerokiego przegladu literatury z zakresu mechaniki zniszczenia izotropowego. Przedstawiono równania stosowane w opisie zniszczenia materiału.
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Implementation of continuum damage in elasto-viscoplastic constitutive equations
PublikacjaW pracy opisano podstawowy wariant modelu Chaboche, oraz założenia i implementacje kontynualnego modelu zniszczenia do komercyjnego programu MES. W pracy zaprazentowano dwa podejścia zobrazowane na przykładach obliczeń numerycznych.
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Practical Applications for Single Pill Combinations in the Cardiovascular Continuum
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Numerical FDM modelling of wave propagation in concrete structure
PublikacjaThe article presents application of finite difference method to damage detection and its size evaluation in concrete structure by elastic wave propagation method. The simulations of wave propagation in concrete structure were performed for six different damage scenarios. Damages were modelled as areas with changed material properties. Investigation focused on the influence of damage size on the energy of wave reflection. Presented...
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Numerical solutions for blood flow in elastic vessels
PublikacjaWe consider the differential–algebraic system for the blood flow and pressure in the systemic arteries. By the operator splitting method, we transform the system into the hyperbolic one, introduce the bicharacteristics, and perform the time–space nonuniform discretization, obtaining the innovative difference scheme. Our results are illustrated with numerical experiments.
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COMPARISON OF INFINITE ELEMENT MODELS
PublikacjaThe main objective of this paper is to show the comparison of two models of infinite ab- sorbing layer with increasing damping in numerical investigations of elastic wave prop- agation in unbounded structures. This has been achieved by the Authors by a careful in- vestigation of two different engineering structures characterised by gradually increasing geometrical and mathematical description complexities. The analysis included...
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Tribology of bone tissue culture in bioreactor.
PublikacjaOpracowano system tribologiczny powstających sił tarcia w bioreaktorze. Pomimo, że wartości sił tarcia osiągają wartości poniżej 0,1 N to mają one decydujący wpływ na wartość porostu tkanki. Mechanika opływu tkanki cieczą o właściwościach biologicznych nienewtonowskich oraz hydrodynamiczna teoria opływu warstwy przyściennej jest bazą wyznaczania parametrów trybologicznychniniejszej pracy.
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Application of a hybrid finite difference-mode matching method to the analysis of circular cavities loaded with cylindrical metallic objects
PublikacjaW artykule przedstawiono badania rezonatorów cylindrycznych zawierających obiekty cylindryczne o dowolnym przekroju poprzecznym z wykorzystaniem metody hybrydowej stanowiącej połączenie metody różnic skończonych z metodą dopasowania rodzajów. W ramach badań określono częstotliwości rezonansowe dla wybranych struktur rezonatorów. Wyniki numeryczne zostały zweryfikowane eksperymentalnie.
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Analysis of scattering from arbitrary configuration of cylindrical objects using hybrid finite-difference mode-matching method
PublikacjaW artykule przedstawiono nową metodę hybrydową stanowiącą połączenie metody różnic skończonych z metodą dopasowania rodzajów, pozwalającą na analizę obiektów cylindrycznych o dowolnym przekroju poprzecznym. W prezentowanej metodzie poszczególne obiekty reprezentowane są poprzez wielorodzajową macierz impednacyjną zdefiniowaną na powierzchni bocznej zastępczego cylindra zawierającego badany obiekt. Celem określenia parametrów rozproszenia...
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Hybrid finite-difference/mode-matching method for analysis of scattering from arbitrary configuration of rotationally-symmetrical posts
PublikacjaW artykule przedstawiona została metoda hybrydowa pozwalająca na analizę zjawiska rozpraszania od dowolnej konfiguracji obiektów o osiowej symetrii. Proponowana metoda oparta jest na reprezentacji obiektu lub dowolnej konfiguracji obiektów poprzez zastępczy obiekt kulisty ze znanymi warunkami brzegowymi. W analizie pojedynczego obiektu wykorzystana została metoda hybrydowa stanowiąca połączenie metody różnic skończonych z metodą...