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Search results for: finite%20element%20modelling
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Rigid Finite Element Modeling for Identification of Vibrations in Elastic in Elastic Rod Driven by a DC-motor Suplied from a Thyristor Rectifier
PublicationRozdział dotyczy analizy numerycznej układu elektromechanicznego. Układ składa się z silnika zasilanego z jednopołówkowego prostownika tysystorowego i napędzanego tym silnikiem wirującego pręta. Celem obliczeń jest określenie postaci i wielkości drgań pręta, jeśli uwzględniamy jego elastyczność. Dyskretna struktura modelu to łańcuch wielomasowy ciał - sztywnych ciał połączonych bezmasowymi węzłami. Autorzy obliczyli zachowanie...
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Comparative Study on Effects of Thermal Gradient Direction on Heat Exchange between a Pure Fluid and a Nanofluid: Employing Finite Volume Method
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Galerkin finite element analysis of Darcy–Brinkman–Forchheimer natural convective flow in conical annular enclosure with discrete heat sources
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The spectral finite element model for analysis of flexural-shear coupled wave propagation. Part 2, Delaminated multilayer composite beam
PublicationW pracy przedstawiono, wykorzystując metodę elementów spektralnych, analizę wpływu delaminacji na propagację fali giętno-ścinającej w belce kompozytowej.
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The spectral finite element model for analysis of flexural-shear coupled wave propagation. Part 1, Laminated multilayer composite beam
PublicationW pracy przedstawiono model spectralnego elementu skończonego umożliwiającego symulację propagacji fali giętno-ścinającej w materiałąch kompozytowych.
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Nonlinear harmonic amplitudes in air coils above and below a metal plate as a function of tensile strength via finite element simulation.
PublicationOpisano wyniki obliczeń numerycznych (symulacja metodą MES) wpływu naprężeń na amplitudy nieliniowych harmonicznych napięcia indukowanego w cewkach powietrznych umieszczonych nad i pod płytą.
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The spectral finite element model for analysis of flexural-shear coupled wave propagation. Part 2: Delaminated multilayer composite beam
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The effective elastic properties of human trabecular bone may be approximated using micro-finite element analyses of embedded volume elements.
PublicationBoundary conditions (BCs) and sample size affect the measured elastic properties of cancellous bone. Samples too small to be representative appear stiffer under kinematic uniform BCs (KUBCs) than under periodicity-compatible mixed uniform BCs (PMUBCs). To avoid those effects, we propose to determine the effective properties of trabecular bone using an embedded configuration. Cubic samples of various sizes (2.63, 5.29, 7.96, 10.58...
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Simulation of hybridized nanofluids flowing and heat transfer enhancement via 3-D vertical heated plate using finite element technique
PublicationThe present study probed the creation of heat energy and concentrating into Newtonian liquids across vertical 3D-heated plates. The role of the Soret and Dufour theories in concentrating and energy formulas is discussed. The role of hybrid nanoparticles is introduced to illustrate particle efciency in terms of solute and thermal energy. It is removed a viscous dissipation process and a changing magnetic feld. The proposed approach...
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The Finite Elements Method application to assesment the impact of turbulence generated by wind turbines on their lacation inclose proximity of overhead high voltage power transmissionlines
PublicationThe paper presents selected aspects of construction of wind turbines location concerning aerodynamic impact on power lines. Reaserch is based on the source data concerning the aerodynamic impact of a wind farm consisting of 8 turbines and 400 kV power line, an analysis of the possibility of wind farm locating in the immediate vicinity of the line was carried out. There are serious problems with locating higher capacity wind farms...
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A constitutive model for concrete based on continuum theory with non-local softening coupled with eXtended Finite Element Method. Computational Modelling of Concrete Structures,
PublicationArtykuł omawia model połączony ciągły-nieciągły do modelowania stref lokalizacji i rys w betonie niezbrojonym. Obliczenia wykonano stosując rozszerzoną metodę elementów skończonych. Wyniki numeryczne porównano z doświadczeniami.
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MHD darcy-forchheimer nanofluid flow and entropy optimization in an odd-shaped enclosure filled with a (MWCNT-Fe3O4/water) using galerkin finite element analysis
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Numerical analysis of elastic wave propagation in unbounded structures
PublicationThe main objective of this paper is to show the effectiveness and usefulness of the concept of an absorbing layer with increasing damping (ALID) in numerical investigations of elastic wave propagation in unbounded engineering structures. This has been achieved by the authors by a careful investigation of three different types of structures characterised by gradually increasing geometrical and mathematical description complexities....
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Wykorzystaniem metody elementów skończonych w obliczaniu stateczności silosu z blachy falistej = Finite element method in determining stability of with corrugated walls strengthened by vertical columns of thin walled open cross section
PublicationGwałtowny rozwój zastosowania MES w działalności inżynierskiej nastąpił w połowie lat osiemdziesiątych w związku z pojawieniem się komputerów osobistych (PC), na które przeniesione zostały programy z dużych jednostek obliczeniowych. W ten sposób efektywne narzędzie rozwiązywania problemów analiz i projektowania jakim jest MES, stało się powszechnie dostępne. W artykule przedstawiono zastosowanie MES w analizie stateczności stalowego...
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Static and dynamic modelling blow- out type trauma of orbital wall
PublicationAuthors of the paper present initial results of finite element analysis of a blow-out type trauma of orbital wall. The research is liked with laboratory tests for the Young’s modulus of bones evaluation. In the finite element analysis the neighbourhood of orbital wall is modelled by triangle thin shell finite elements. In the paper results of nonlinear static and transient dynamic analysis (including damping) are compared. The...
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Young’s modulus distribution in the FEM models of bone tissue
PublicationThis paper presents how differences of Young’s modulus in adjacent finite elements typical for organic materials such as bone tissue, influence stress calculating. Emphasizing high computational cost of variable Young’s modulus in parts of the model, where the number of finite elements has been raised, the authors wants to prove that new model of finite element which has variable Young’s modulus in its volume needs to be created....
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A new library for construction of automata
PublicationWe present a new library of functions that construct minimal, acyclic, deterministic, finite-state automata in the same format as the author's fsa package, and also accepted by the author's fadd library of functions that use finite-state automata as dictionaries in natural language processing.
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Wave propagation in plate structures for crack detection
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Numerical analysis of elastic wave propagation in unbounded structures
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Wave propagation in plate structures for crack detection.
PublicationW pracy przedstawiono analizę propagacji fali poprzecznej w płycie z pęknięciem. Do modelowania zagadnienia zastosowano metodę elementów spektralnych.
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Propagation of in-plane waves in an isotropic panel with a crack
PublicationW pracy przedstawiono model tarczowego elementu spektralnego do analizy propagacji fali wzdłuznej w panelach z uszkodzeniami.
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Numerical analysis of size effect in RC beams scaled along height or length using elasto-plastic-damage model enhanced by non-local softening.
PublicationArtykuł omawia wyniki numeryczne dotyczące efektu skali w belkach żelbetowych uzyskane stosując metodę elementów skończonych. Dwuwymiarowe obliczenia wykonano dla belek żelbetowych podczas 4-punktowego zginania. Belki były skalowane wzdłuż wysokości lub długości. Beton został opisany prawem sprężysto-plastycznym z degradacją sztywności, rozszerzonym o nielokalność w osłabieniu. Wyniki numeryczne zostały porównane z wynikami doświadczalnymi....
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FE analysis of reinforced concrete corbels with enhanced continuum models
PublicationW artykule pokazano wyniki MES symulacji wsporników żelbetowych. Zachowanie wsporników modelowano przy zastosowaniu 3 różnych modeli betonu: sprężysto-plastycznego, degradacji sprężystej i rozmytych rys. Modele rozszerzono o długość mikrostruktury przy zastosowaniu teorii nielokalnej. Wyniki numeryczne porównano z doświadczeniami z literatury.
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FE analysis of size effects in reinforced concrete beams without shear reinforcement based on stochastic elasto-plasticity with non-local softening.
PublicationW artykule przedstawiono wyniki analizy MES dotyczącej deterministycznego i statystycznego efektu skali w żelbetowych belkach bez zbrojenia na ścinanie. W analizie zastosowano prawo sprężysto-plastyczne z nielokalnym osłabieniem. Wyniki analizy porównano z doświadczeniami i modelem skali Bazanta.
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An Efficient Simulation Method of Massive MIMO Antenna Arrays used in 5G Mobile Phones
PublicationThis paper deals with a model-order reduction method, applied to speed-up the simulations of MIMO antenna arrays, performed by means of finite element method. The obtained results of the numerical tests show that the described technique is reliable and considerably increases the efficiency of the standard finite element method.
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Modelling of high frequency dynamic responses of engineering structures
PublicationModelling of high frequency dynamic responses of engineering structures, especially those related to wave propagation, is a real numerical challenge. Nowadays most of numerical models, used for that purpose, are based on the application of various finite element techniques. However, finite element discrete models may also be considered as possessing certain periodic structures, which may manifest themselves in particular scenarios....
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Electromagnetic plane wave scattering from a cylindrical object with an arbitrary cross section using a hybrid technique
PublicationA hybrid technique combining finite-element and mode-matching methods for the analysis of scattering problems in open and closed areas is presented. The main idea of the analysis is based on the utilization of the finite-element method to calculate the post impedance matrix and combine it with external excitation. The discrete analysis, which is the most time- and memory-consuming, is limited here only to the close proximity of...
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Asymptotic Expansion Method with Respect to Small Parameter for Ternary Diffusion Models
PublicationTernary diffusion models lead to strongly coupled systems of PDEs. We choose the smallest diffusion coefficient as a small parameter in a power series expansion whose components fulfill relatively simple equations. Although this series is divergent, one can use its finite sums to derive feasible numerical approximations, e.g. finite difference methods (FDMs).
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Reduced order models in computational electromagnetics (in memory of Ruediger Vahldieck)
PublicationThis paper reviews research of Ruediger Vahldieck's group and the group at the Gdansk University of Technology in the area of model order reduction techniques for accelerating full-wave simulations. The applications of reduced order models to filter design as well as of local and nested(multilevel) macromodels for solving 3D wave equations and wave-guiding problems using finite difference and finite element methods are discussed.
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Linear Micropolar Elasticity Analysis of Stresses in Bones Under Static Loads
PublicationWe discuss the finite element modeling of porous materials such as bones using the linear micropolar elasticity. In order to solve static boundary-value problems, we developed new finite elements, which capture the micropolar behavior of the material. Developed elements were implemented in the commercial software ABAQUS. The modeling of a femur bone with and without implant under various stages of healing is discussed in details
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Moments of Hermite-Gaussian functionals
PublicationMoments of finite products of Hermite-Gaussian functionals are expressed by covariances of Gaussian sequence.
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Techniki zwiększania efektywności metody elementów skończonych poprzez redukcję dziedziny obliczeniowej z wykorzystaniem własności geometrii struktur
PublicationWspółczesna elektronika ze względu na swój szybki rozwój wymaga od nas efektywnego modelowania zjawisk polowych. Celem rozprawy jest zwiększanie efektywności metody elementów skończonych poprzez redukcję dziedziny obliczeniowej z wykorzystaniem własności geometrii struktur oraz jej hybrydyzację z użyciem technik analitycznych. Rozprawa zawiera przegląd stanu wiedzy na temat dostępnych obecnie technik modelowania jak również opis...
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FEM and experimental investigations of concrete temperature field in the massive stemwall of the bridge abutment
PublicationThe paper deals with the prediction of early-age concrete temperature of cast-in-place stemwall of the bridge abutment. The considered object is an arch bridge located in Gda´nsk. In the case of massive structures, it is particularly important to not exceed the temperature difference between the core and the concrete surface. Too high temperature gradient generates an increase in thermal stresses, what could be the reason of exceeding...
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RADIATION OF HIGH INTENSITY SOUND BY CIRCULAR DISC BY MEANS OF THE NUMERICAL METHOD
PublicationThe main goal of this paper is to find sound pressure distribution radiated by the circular piezoelectric disc that vibrates with the finite amplitude. There has been presented the pressure distribution close to the radiating surface. Also it is shown the sound pressure distribution in the 3D form. The mathematic modeling was carried out on the base of the nonlinear acoustic equation with the proper boundary condition. The axial...
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Multidisciplinary approach to the assessment of historic structures based on the case of a masonry bridge in Galicia (Spain)
PublicationThe paper presents a general method to evaluate a masonry structure with a complex geometry and unknown material properties. This multidisciplinary approach integrates close range digital photogrammetry,ground probing radar (GPR) and finite elements analysis (FEM) to analyse a masonry bridge. The resulting information from photogrammetry and radar is applied to define a 3D model, which is then used to simulate the behaviour of...
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Sophistication assessment of existing FEM models of orbital blowout trauma: Is models valuation justified?
PublicationAfter a thorough study of the work entitled “Development and validation of an optimized finite element model of the human orbit”, some doubts aroused concerning the sophistication assessment of the existing finite element method (FEM) models of orbital blow-out. Although the work was unquestionably innovative, and the results were not only fascinating but also invaluable, the authors stated that their model was the most sophisticated...
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Chromatic cost coloring of weighted bipartite graphs
PublicationGiven a graph G and a sequence of color costs C, the Cost Coloring optimization problem consists in finding a coloring of G with the smallest total cost with respect to C. We present an analysis of this problem with respect to weighted bipartite graphs. We specify for which finite sequences of color costs the problem is NP-hard and we present an exact polynomial algorithm for the other finite sequences. These results are then extended...
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FE analysis of support-specimen interaction of compressive experimental test
PublicationThe objective of this work is to investigate the support-specimen interaction during the compressive experimental testing of stiffened plates. The interaction is analyzed employing the nonlinear Finite Element Method using the commercial software ANSYS. The connection between the stiffened plate and testing supports is modelled with the use of contact elements, where several possible interaction scenarios are investigated, and...
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Dyskretno-ciągła metoda modelowania układów dynamicznych
PublicationW artykule przedstawiono oryginalną metodę modelowania układów dyskretno-ciągłych. Metoda polega na dyskretyzowaniu układu trójwymiarowego jedynie w dwóch wybranych kierunkach. W trzecim z kierunków układ pozostaje ciągły. Otrzymany w ten sposób model jest modelem dyskretno-ciągłym. Opisany jest za pomocą równań różniczkowych cząstkowych. Ogólne równania różnicowe układu dyskretnego otrzymano, wykorzystując metodę sztywnych elementów...
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GPR simulations for diagnostics of a reinforced concrete beam
PublicationThe most popular technique for modelling of an electromagnetic field, the finite difference time domain (FDTD) method, has recently become a popular technique as an interpretation tool for ground penetrating radar (GPR) measurements. The aim of this study is to detect the size and the position of damage in a reinforced concrete beam using GPR maps. Numerical simulations were carried out using the finite differ-ence time domain...
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Hybrid Method Analysis of Unshielded Guiding Structures
PublicationA combination of mode matching, finite element methods and generalized impedance matrix is presented in a context of propagation problems for open guiding structures. The computational domain is divided into two regions: the first one is a circular cylinder containing whole guiding structure and the second one surrounds this artificial cylinder. The impedance matrix is calculated with the use of finite element method in the first...
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O projektowaniu ściany szczelinowej
PublicationW pracy przedstawiono proces weryfikacji i porównania obliczeń otrzymanych z programu bazującego na metodzie elementów skończonych z wynikami analitycznymi dla analizowanej ściany szczelinowej z przyporą ziemną. Dodatkowo autorzy dokonali krótkiego przeglądu literatury z zakresu ścian szczelinowych.
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O zbieżności rozwiązań w nieliniowym mikropolarnym ośrodku sprężysto-plastycznym - zastosowanie elementów skończonych wyższego rzędu.
PublicationEfekty lokalizacji w nieliniowym geometrycznie sprężysto-plastycznym mikropolarnym ośrodku z osłabieniem materiału. Hipotezy Hubera-Misesa-Hencky’ego i Druckera-Pragera. Rozwiązanie równań sprężysto-plastycznych przy użyciu algorytmu powrotnego. Opis zastosowanych elementów skończonych. Przykłady numeryczne obliczeń w geotechnice.
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Contact with coupled adhesion and friction: Computational framework, applications, and new insights
PublicationContact involving soft materials often combines dry adhesion, sliding friction, and large deformations. At the local level, these three aspects are rarely captured simultaneously, but included in the theoretical models by Mergel et al., (2019). We here develop a corresponding finite element framework that captures 3D finite-strain contact of two deformable bodies. This framework is suitable to investigate sliding friction even...
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Analiza wrażliwości tarczy z wykorzystaniem metody elementów skończonych
PublicationW pracy przedstawiono przykład zastosowania analizy wrażliwości tarczy modelowanej przy pomocy metody elementów skończonych. Podstawy teoretyczne oraz przykład numeryczny dotyczą wpływu różnicowania grubości całej tarczy oraz jej obszarów – jako zmiennej pro-jektowej – na przemieszczenie wybranego punktu – jako zmiennej stanu.
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A Hopf type theorem for equivariant local maps
PublicationWe study otopy classes of equivariant local maps and prove a Hopf type theorem for such maps in the case of a real finite-dimensional orthogonal representation of a compact Lie group.
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A Nonlinear Model of a Mesh Shell
PublicationFor a certain class of elastic lattice shells experiencing finite deformations, a continual model using the equations of the so-called six-parameter shell theory has been proposed. Within this model, the kinematics of the shell is described using six kinematically independent scalar degrees of freedom — the field of displacements and turns, as in the case of the Cosserat continuum, which gives reason to call the model under consideration...
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Investigation of buckling resistance of columns using non-linear static and dynamic analysis
PublicationThe aim of this paper is to investigate the stability process in an axially compressed column using a static and dynamic finite element analysis by taking both the geometric and material non-linearity into account. The perfect column and column with geometric imperfections were analysed. The linear buckling analyses were used to obtain the lowest buckling load and shapes of buckled forms that were taken into account as initial...
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SIMULATION OF PROCEED® SURGICAL MESH APPLIED TO VENTRAL HERNIA REPAIR
PublicationIn the present research, Proceed® implant is considered. The system is subjected to short-time dynamic pressure load, similar to post-operative cough naturally occurring in human abdomen. The model refers to a clinical case of 5cm of hernia operated by Proceed implant fixed by 15 joints every 3cm around the orifice. The simulations of the implanted mesh are performed by means of the Finite Element Method. The implant is modelled...
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The modelling method of discrete-continuous systems
PublicationThe paper introduces a method of discrete-continuous systems modelling. In the proposed method a three-dimensional system is divided into finite elements in only two directions, with the third direction remaining continuous. The thus obtained discrete-continuous model is described by a set of partial differential equations. General difference equations of discrete system are obtained using the rigid finite element method. The limit...