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Search results for: VISCOELASTIC CONTACT ELEMENT
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Viscoelastic properties of oil-in-water emulsions stabilized by acylpropyleneglycol emulsifiers obtained with sodium soaps
PublicationZbadano właściwości reologiczne emulsji typu O/W, stabilizowanych emulgatorami acylopropylenoglikolowymi. Do badań wykorzystano reometr o kontrolowanym naprężeniu ścinającym. Wykonano testy oscylacyjne tzw. ''dużej deformacji próbki'' oraz analizy typu ''pełzanie i powrót''. Stwierdzono, że właściwości lepkosprężyste emulsji determinowane były składem stosowanego emulgatora. Wszystkie badane układy emulsyjne charakteryzowały się...
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Experimental determination of impact stiffness parameters for the non-linear viscoelastic model of pounding force
PublicationNieliniowy model lepko-sprężysty umożliwia dokładną symulację siły zderzenia w czasie oraz symulację odpowiedzi konstrukcji podatnej na zderzanie podczas trzęsień ziemi. Celem tego artykułu jest eksperymentalne wyznaczenie wartości współczynnika sztywności zderzenia jako parametru tegoż modelu.
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Investigation of the Efficiency of a Dual-Fuel Gas Turbine Combustion Chamber with a Plasma‒Chemical Element
PublicationThe study is devoted to the possibility of increasing the efficiency of the working process in dual-fuel combustion chambers of gas turbine engines for FPSO vessels. For the first time, it is proposed to use the advantages of plasma‒chemical intensification of the combustion of hydrocarbon fuels in the dual-fuel combustion chambers, which can simultaneously operate on gaseous and liquid fuels. A design scheme of a combustion chamber...
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Unequally-Spaced Slot Strategy for Radiation Null Reduction in Single SIW-Embedded Antenna Element
PublicationThe incorporation of higher-order modes (HOMs) can substantially augment the antenna gain and bandwidth, but this improvement is typically accompanied by compromised radiation performance including radiation nulls and higher side lobe levels. In this study, an inventive strategy is introduced to reduce the radiation nulls and the side lobe levels of a single antenna element by positioning multiple slots of the radiating element...
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GPU-Accelerated Finite-Element Matrix Generation for Lossless, Lossy, and Tensor Media [EM Programmer's Notebook]
PublicationThis paper presents an optimization approach for limiting memory requirements and enhancing the performance of GPU-accelerated finite-element matrix generation applied in the implementation of the higher-order finite-element method (FEM). It emphasizes the details of the implementation of the matrix-generation algorithm for the simulation of electromagnetic wave propagation in lossless, lossy, and tensor media. Moreover, the impact...
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Modelling of Longitudinal Elastic Wave Propagation in a Steel Rod Using the Discrete Element Method
PublicationThe paper deals with the issue of modelling elastic wave propagation using the discrete element method (DEM). The case of a longitudinal wave in a rod with a circular cross-section was considered. A novel, complex algorithm consisting of the preparation of models and simulation of elastic waves was developed. A series of DEM models were prepared for simulations, differing in discretisation and material parameters. Additional calculations...
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GPU Acceleration of Multilevel Solvers for Analysis of Microwave Components With Finite Element Method
PublicationThe letter discusses a fast implementation of the conjugate gradient iterative method with ${rm E}$-field multilevel preconditioner applied to solving real symmetric and sparse systems obtained with vector finite element method. In order to accelerate computations, a graphics processing unit (GPU) was used and significant speed-up (2.61 fold) was achieved comparing to a central processing unit (CPU) based approach. These results...
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Reliable Greedy Multipoint Model-Order Reduction Techniques for Finite-Element Analysis
PublicationA new greedy multipoint model-order reduction algorithm for fast frequency-domain finite-element method simulations of electromagnetic problems is proposed. The location of the expansion points and the size of the projection basis are determined based on a rigorous error estimator. Compared to previous multipoint methods, the quality of the error estimator is significantly improved by ensuring the orthogonality of the projection...
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Planning of the green road system as an element of spatial management in suburbs and small towns
PublicationThe premise for the development of sustainable forms of road infrastructure in small towns is the appropriate plan at an early stage or modifi cation in the case of existing spaces. A multi-directional approach is extremely important, which takes into account the specifi city of the regional (country) road system, availability, and capacity of traffi c network, but also social and environmental factors. Effi cient management...
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Local Mesh Deformation for accelerated parametric studies based on the Finite Element Method
PublicationThis paper presents an approach for enhancing the efficiency of two-dimensional Finite Element Method analysis in parametric studies or optimisation process of microwave components. The new approach involves local mesh deformation applied near the elements that are modified during computations. Since in the proposed approach the topology of the mesh remains unchanged, a new mesh does not have to be generated from scratch when the...
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Spectral Finite Element Method in Condition Monitoring and Damage Detection
PublicationIt is well known that the dynamic behaviour of engineering structures may carry very important and crucial information that can be further used for the assessment of their condition as well as detection of any damage induced. The current interest in monitoring techniques based on the propagation of guided elastic waves requires that numerical techniques used for modelling the phenomena associated must shift into the realm of high...
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Simulations of Shear Zones and Cracks in Engineering Materials Using eXtended Finite Element Method
PublicationNumerical simulations of cracks and shear zones in quasi-brittle materials are presented. Extended Finite Element Method is used to describe both cracks and shear zones. In a description of tensile cracks, a Rankine criterion is assumed. A discrete Mohr-Coulomb law is adopted for simulations of shear zones. Results of simple numerical tests: unixial tension, bending and biaxial compression are demonstrated.
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Element sensor based on microplasma generators
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Communication and Load Balancing Optimization for Finite Element Electromagnetic Simulations Using Multi-GPU Workstation
PublicationThis paper considers a method for accelerating finite-element simulations of electromagnetic problems on a workstation using graphics processing units (GPUs). The focus is on finite-element formulations using higher order elements and tetrahedral meshes that lead to sparse matrices too large to be dealt with on a typical workstation using direct methods. We discuss the problem of rapid matrix generation and assembly, as well as...
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Use of Neural Networks in Diagnostics of Rolling-Element Bearing of the Induction Motor
PublicationBearing defect is statistically the most frequent cause of an induction motor fault. The research described in the paper utilized the phenomenon of the current change in the induction motor with bearing defect. Methods based on the analysis of the supplying current are particularly useful when it is impossible to install diagnostic devices directly on the motor. The presented method of rolling-element bearing diagnostics used indirect...
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Application of the Boundary Element Method for the Simulation of Two-dimensional Viscous Incompressible Flow
PublicationThe paper presents the application of an indirect variant of the boundary element method (BEM) to solve the two-dimensional steady flow of a Stokes liquid. In the BEM, a system of differential equations is transformed into integral equations. Thi smakes it possible to limit discretization to the border of the solution. Numerical discretization of the computational domain was performed with linear boundary elements, for which a...
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Analytical and experimental determination of parameters for the non-linear viscoelastic model of earthquake-induced structural pounding
PublicationNieliniowy model lepko-sprężysty umożliwia dokładną symulację siły zderzenia w czasie oraz symulację odpowiedzi konstrukcji podatnej na zderzanie podczas trzęsień ziemi. Jednym z celów niniejszego artykułu jest wyprowadzenie wzoru na zależność pomiędzy liczbą tłumienia zderzenia (parametr wspomnianego modelu), a współczynnikiem odbicia. Kolejnym celem jest wyznaczenie zakresu wartości współczynników odbicia oraz współczynników...
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Non contact multiband emissivity measurment. bibliogr.Optoelectronic and Electronic Sensors.
PublicationW pracy zaproponowano i opisano wielopasmowa pasywną metodę pomiaru emisyjności obiektu. W oparciu o opracowany model matematyczny przeprowadzona została analiza systemu pomiarowego. Wyniki modelowania umożliwiają ocenę dokładności projektowanego systemu.
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Automated non destructive testing by non-contact surface waves
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Contact problems in lock gates in view of investigation and field experience
PublicationW artykule przedstawiono ogólny przegląd zagadnień kontaktowych zamknięć wodnych. Szczególną uwagę zwrócono na siły kontaktowe, zagadnienia trybologiczne i inne o dużym znaczeniu mające wpływ na projektowanie i eksploatację elementów kontaktowych i na całość elementów kontaktowych zapewniających stateczność całego układu zamknięć wodnych. Podano wyniki badań w laboratorium symulujących pracę zamknięć. Zaproponowano nowe rozwiązania...
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Numerical modeling of force and contact networks in fragmented sea ice
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Contact angle of the ferronanofluid and influence of the magnetic field on the drying droplet
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The rolling contact fatigue of WC/C-coated spur gears
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Food microstructure systems modelling regarding interaction and contact phenomena.
PublicationPrzedstawiono wybrane fragmenty teorii modelowania w strukturach rozproszonych mikrostruktury żywności, w których zostały uwzględnione wzajemne oddziaływania cząstek oraz występujące zjawiska kontaktowe. Do oszacowania tych oddziaływań wykorzystano zmodyfikowany przez autora model Buczkowskiego i Kleibera.
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Hydraulic gate contact areas in view of investigation and field experience
PublicationW pracy podano ogólny przegląd dotyczący określenia powierzchni kontaktowych zamknięć wodnych. Szczególną uwagę zwrócono na siły występujące w powierzchniach kontaktowych zamknięć, trybologię i inne zjawiska mające wpływ na rozwiązania problemów kontowych określających sprawność zamknięć. Ważnym zagadnieniem jest dobór materiału i określenie jego właściwości na podstawie badań laboratoryjnych i oceny pracy tego materiału w wyniku...
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2D Mathematical Model of the Commutator Sliding Contact of an Electrical Machine
PublicationW artykule przedstawiono model matematyczny 2D komutatorowego zestyku ślizgowego z wieloma stopniami swobody. W modelu uwzględniono zmienne wymuszenia działające na szczotkę. Wymuszenia te są wynikiem falistości wirującego komutatora. Szczotka została zamodelowana jako system wielu mas, elementów sprężystych i tłumików rozłożonych w kierunku stycznym i promieniowym. Zamodelowano wszystkie oddziaływania lepkosprężyste pomiędzy komutatorem...
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Modeling of the behavior of granular bodies using DEM with contact moments
PublicationW artykule przedstawiono wyniki symulacji badania trójosiowego dla materiałów granulowanych. Obliczenia wykonano przy zastosowaniu metody DEM. Pokazano wpływ momentów kontaktowych na wytrzymałość próbki. Zbadano wpływ parametrów mikroskopowych.
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Finite element/mode-matching analysis of ferrite/dielectric line junctions of arbitrary cross-section
PublicationThis paper is focused on the analysis of line junctions obtained as a cascade of dielectric and ferrite guides of arbitrary cross-section. The main application of such structures is nonreciprocal devices such as isolators, circulators, or phase shifters. The efficient finite element/mode-matching approach is proposed to the analysis of such structures. In this approach, thefiniteelementmethod is applied todetermine propagation...
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An optimal form of the finite element mass matrix in the analysis of longitudinal vibrations of rods
PublicationIn this paper, an attempt is made to find the optimal form of the mass matrix of a rod finite element, which allows one to obtain the smallest errors in the longitudinal frequency determination of natural vibrations of any boundary conditions within the whole range of determined frequencies. It is assumed that the mass matrix can be treated as a linear combination of the consistent and diagonal matrices. Based on analytical considerations,...
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CO2 capture through direct-contact condensation in a spray ejector condenser and T- junction separator
PublicationThe design principle underlying the steam condensation and CO2 purification in a gas power plant with a focus on reducing CO2 emissions encompasses the deployment of a spray ejector condenser (SEC) and separator. This innovative system facilitates direct-contact condensation of steam with non-condensable gas (CO2) by inter acting with a spray of subcooled water, seamlessly integrated with a T-junction separator mechanism aimed...
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Application of the finite element methods in long-term simulation of the multi-physics systems with large transient response differences
PublicationApplication of the Finite Element Method (FEM) and the Multibody Dynamics Method allows analyzing of complex physical systems. Complexity of the system could be related both to the geometry and the physical description of phenomenon. The metod is the excellent tool for analyzing statics or dynamics of the mechanical systems, and permits tracking of Multi Body System (MBS) transient response for the long-term simulations and application...
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Finite element modelling of a historic church structure in the context of a masonry damage analysis
PublicationThe paper includes a case study of modelling a real historic church using the finite element method (FEM) based on laser scans of its geometry. The main goal of the study was the analysis of the causes of cracking and crushing of masonry walls. An FEM model of the structure has been defined in ABAQUS. A non-linear dynamic explicit analysis with material model including damage plasticity has been performed. A homogenization procedure...
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SSFR Test of Synchronous Machine for Different Saturation Levels using Finite-Element Method
PublicationIn this paper the StandStill Frequency Response characteristics (SSFR) of saturated synchronous generator (SG) have been calculated using Finite Element Method (FEM) analysis. In order to validate proposed approach for unsaturated conditions FEM simulation from Flux2D software has been compared with the measurements performed on the 10 kVA, 4- poles synchronous machine ELMOR GCe64a of salient rotor construction, equipped with a...
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An isogeometric finite element formulation for geometrically exact Timoshenko beams with extensible directors
PublicationAn isogeometric finite element formulation for geometrically and materially nonlinear Timoshenko beams is presented, which incorporates in-plane deformation of the cross-section described by two extensible director vectors. Since those directors belong to the space R3, a configuration can be additively updated. The developed formulation allows direct application of nonlinear three-dimensional constitutive equations without zero...
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Impact of the Finite Element Mesh Structure on the Solution Accuracy of a Two-Dimensional Kinematic Wave Equation
PublicationThe paper presents the influence of the finite element mesh structure on the accuracy of the numerical solution of a two-dimensional linear kinematic wave equation. This equation was solved using a two-level scheme for time integration and a modified finite element method with triangular elements for space discretization. The accuracy analysis of the applied scheme was performed using a modified equation method for three different...
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A general isogeometric finite element formulation for rotation‐free shells with in‐plane bending of embedded fibers
PublicationThis article presents a general, nonlinear isogeometric finite element formulation for rotation-free shells with embedded fibers that captures anisotropy in stretching, shearing, twisting, and bending - both in-plane and out-of-plane. These capabilities allow for the simulation of large sheets of heterogeneous and fibrous materials either with or without matrix, such as textiles, composites, and pantographic structures. The work...
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Simulation of unsteady flow over floodplain using the diffusive wave equation and the modified finite element method
PublicationWe consider solution of 2D nonlinear diffusive wave equation in a domain temporarily covered by a layer of water. A modified finite element method with triangular elements and linear shape functions is used for spatial discretization. The proposed modification refers to the procedure of spatial integration and leads to a more general algorithm involving a weighting parameter. The standard finite element method and the finite difference...
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Nonlinear finite element modeling of vibration control of plane rod-type structural members with integrated piezoelectric patches
PublicationThis paper addresses modeling and finite element analysis of the transient large-amplitude vibration response of thin rod-type structures (e.g., plane curved beams, arches, ring shells) and its control by integrated piezoelectric layers. A geometrically nonlinear finite beam element for the analysis of piezolaminated structures is developed that is based on the Bernoulli hypothesis and the assumptions of small strains and finite...
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Experimental and numerical study on polymer element used for reduction of temporary steel grandstand vibrations
PublicationThe purpose of the paper is to analyse the effectiveness of a polymer damper in reduction of a temporary steel grandstand vibrations through the experimental and numerical study. The damper considered in the investigation is constructed out of two L-shape steel members bonded with polymer mass of high damping properties. The element has been installed as a diagonal one at the back part of the structure. The method has been compared...
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On the Possibility of Improving the Oxidation Resistance of High-Chromium Ferritic Stainless Steel Using Reactive Element Oxide Nanoparticles
PublicationHigh-chromium ferritic steels are current the only viable candidates for cheap interconnect materials for application in high-temperature solid oxide fuel and electrolyzer cells (HT-SOFCs/SOECs). The durability and operating characteristics of interconnects manufactured using these materials may be improved significantly by applying a protective-conducting MoCo2O4 coating and depositing an intermediate layer consisting of nanoparticles...
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A higher order transversely deformable shell-type spectral finite element for dynamic analysis of isotropic structures
PublicationThis paper deals with certain aspects related to the dynamic behaviour of isotropic shell-like structures analysed by the use of a higher order transversely deformable shell-type spectral finite element newly formulated and the approach known as the Time-domain Spectral Finite Element Method (TD-SFEM). Although recently this spectral approach is reported in the literature as a very powerful numerical tool used to solve various...
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Acute Effects of Isometric Conditioning Activity on the Viscoelastic Properties of Muscles and Sprint and Jumping Performance in Handball Players
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Arc Ignition Process in Short Fuses Element
PublicationPrzedstawiono wyniki badań zapłonu łuku elektrycznego w topiku w warunkach dużej stromości narastania gęstości prądu, do 5.19 9 A s-1 mm-2. Wyznaczono podziałkę rozpadu topika (0,04-0,12 mm) oraz napięcie zapłonu na elementarnej przerwie topika (20-30 V). Wykazano w badaniach doświadczalnych modelu fizycznego topika rozpad i ponowne łączenie sąsiednich elementarnych przerw.
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Lattice dynamics of the rare-earth element samarium
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Fortyfikacje jako element zieleni miejskiej Gdańska
PublicationOmówienie zasobu wartości materialnych i niematerialnych krajobrazu historycznego Gdańska na obszarach związanych z kolejnymi systemami obronnymi miasta. Zaprezentowanie propozycji współczesnych działań w zakresie kompozycji zieleni uczytelniających zdezintegrowaną kompozycję przestrzenną historycznych systemów obronnych Gdańska.
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Mebel jako integralny element obiektu architektonicznego
PublicationProjektant mebli, będąc architektem, może swobodnie obrać właściwą mu strategię pracy, czyli stawiać meble w roli elementów organizujących przestrzeń, przekazujących treść, współdecydujących o odczuciach i doznaniach użytkowników i odbiorców. Dlatego zaprezentowany i przeanalizowany został sposób ‘meblowania przestrzeni’ rozumiany jako jej doposażanie obiektami spoza struktury architektonicznej zaprojektowanymi jednak jako integralne...
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Turbina wiatrowa jako element systemu radiolokalizacyjnego
PublicationW referacie zaproponowano wykorzystanie turbiny wiatrowej do umieszczenia elementów systemu radiolokalizacyjnego do określania położenia obiektów latających. Zaproponowane rozwiązanie umożliwia osza-cowanie położenia obiektu w przestrzeni, zwłaszcza w ruchu, za pomocą sygnałów lokalizacyjnych nadawanych jednocześnie z wybranych punktów konstrukcyjnych turbiny. Przedstawiono matematyczną analizę metody oraz algorytm Chana (CA) do...
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Kształtowanie płynności jako element zarządzania przedsiębiorstwem
PublicationKształtowanie płynności w przedsiębiorstwie wymaga zarządzania kapitałem obrotowym, zgodnie z przyjętą strategią: agresywną, umiarkowaną lun konserwatywną. Zarządzając kapitałem obrotowym należy zarządzać środkami pieniężnymi, należnościami i zobowiązaniami oraz zapasami.
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Podziemny element. Skrzynka rozsączająca - świadomy wybór
PublicationProblemy wyboru skrzynki rozsączającej wody opadowe. Charakterystyczne rozwiązania, problemy, konsekwencje
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Diagonalized Macromodels in Finite Element Method for Fast Electromagnetic Analysis of Waveguide Components
PublicationA new technique of local model-order reduction (MOR) in 3-D finite element method (FEM) for frequency-domain electromagnetic analysis of waveguide components is proposed in this paper. It resolves the problem of increasing solution time of the reduced-order system assembled from macromodels created in the subdomains, into which an analyzed structure is partitioned. This problem becomes particularly relevant for growing size and...