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wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: ISOGEOMETRIC ANALYSIS, KIRCHHOFF–LOVE SHELLS, MULTIPLICATIVE SPLIT, NONLINEAR FINITE ELEMENT METHODS, SURFACE ELASTICITY, VISCOELASTICITY
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Extended non-linear relations of elastic shells undergoing phase transitions
PublikacjaThe non-linear theory of elastic shells undergoing phase transitions was proposed by two first authors in J. Elast. 79, 67-86 (2004). In the present paper the theory is extended by taking into account also the elastic strain energy density of the curvilinear phase interface as well as the resultant forces and couples acting along the interface surface curve itself. All shell relations are found from the variational principle of...
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Numerical analysis of laminated shells under in-plane axial compression
PublikacjaW pracy analizowana jest stateczność powłoki warstwowej poddanej osiowemu ściskaniu. Badany jest wpływ wariantów uwarstwienia oraz warunków podparcia krawędzi obciążonej na zachowanie konstrukcji. Wyniki numeryczne porównano z eksperymentem.
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Single and Dual-GPU Generalized Sparse Eigenvalue Solvers for Finding a Few Low-Order Resonances of a Microwave Cavity Using the Finite-Element Method
PublikacjaThis paper presents two fast generalized eigenvalue solvers for sparse symmetric matrices that arise when electromagnetic cavity resonances are investigated using the higher-order finite element method (FEM). To find a few loworder resonances, the locally optimal block preconditioned conjugate gradient (LOBPCG) algorithm with null-space deflation is applied. The computations are expedited by using one or two graphical processing...
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Financial Analysis exercises - New (copy)
Kursy OnlineTo obtain theoretical and practical experience of financial and economic analysis. Methods of economic analysis: Elements of production and human resources analysis, tangible assets analysis, inventory analysis, which would enable to understand the business case, to measure them and find suitable decision. To obtain theoretical and practical experience of financial analysis.
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On constitutive relations in the resultatnt non-linear theory of shells
PublikacjaThe authors summarize their current research in the field of constitutive modelling in the framework of non-linear 6-parameter shell theory. In particular the description of isotropic, multilayered composite and functionally graded shells is presented.
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CE-MS and GC-MS as “Green” and Complementary Methods for the Analysis of Biogenic Amines in Wine
PublikacjaTwo novel complementary analytical methods, namely an extraction-free capillary electrophoresis coupled to mass spectrometry (CE-MS) and direct immersion-solid-phase microextraction combined with gas chromatography-mass spectrometry (DI-SPME-GC-MS), have been developed and successfully applied for the determination of biogenic amines (BAs) in wine and fruit wine. They have been rigorously compared to each other in terms of various...
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Inverse and forward surrogate models for expedited design optimization of unequal-power-split patch couplers
PublikacjaIn the paper, a procedure for precise and expedited design optimization of unequal power split patchcouplers is proposed. Our methodology aims at identifying the coupler dimensions that correspond to thecircuit operating at the requested frequency and featuring a required power split. At the same time, thedesign process is supposed to be computationally efficient. The proposed methodology involves two typesof auxiliary models (surrogates):...
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Energy Consumption Analysis Methods in Industry
PublikacjaThis paper overviews applied methods to evaluate energy consumption in Industry. The most important law regulations are presented, which decide on the necessity to conduct an effec - tive energetic economy. Basic assumptions are defined to calculate direct and cumulative energy consumption. The pros and cons of using each method are presented.
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Chemical surface etching methods for ground tire rubber as sustainable approach for environmentally-friendly composites development– a review
PublikacjaGround tire rubber (GTR) has been used as a sustainable low-cost modifier in various composites. However, due to the hydrophobic nature of GTR, it is in compatible with most matrices and results in deterioration in both mechanical and physical properties of composites. This necessitates pre-modification of the powdered rubber to improve the interfacial bonding at the rubber-matric interface. The most common GTR modification research...
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Preconditioners with Low Memory Requirements for Higher-Order Finite-Element Method Applied to Solving Maxwell’s Equations on Multicore CPUs and GPUs
PublikacjaThis paper discusses two fast implementations of the conjugate gradient iterative method using a hierarchical multilevel preconditioner to solve the complex-valued, sparse systems obtained using the higher order finite-element method applied to the solution of the time-harmonic Maxwell equations. In the first implementation, denoted PCG-V, a classical V-cycle is applied and the system of equations on the lowest level is solved...
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Karol Grębowski dr inż.
OsobyKarol Grębowski (dr inż.) pracuje jako adiunkt w Katedrze Technicznych Podstaw Projektowania Architektonicznego na Wydziale Architektury Politechniki Gdańskiej. Jego badania naukowe dotyczą zjawisk szybkozmiennych zachodzących podczas drgań konstrukcji budowlanych, obiektów mostowych (trzęsienia ziemi) oraz badania w zakresie metodologii projektowania budynków stanowiących system ochrony pasywnej (SOP) odpornych na uderzenia pojazdów...
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Computer Supported Analysis of the Human Body Surface Area
PublikacjaRecent scientific studies show the growing importance of the coefficients: BSA and TBSA, as an alternative to the widely used BMI. The relevant indicators are widely used in medicine, including such areas as: the treatment of burns, chemotherapy, dermatology and toxicology; as benchmarks when calculating doses of drugs and fluids. The particular problems concerning this subject are: the change of the reference parameter value which...
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Analysis of magnetic field distribution inside ferromagnetic thin shells during degaussing process
PublikacjaAnalysis of the demagnetization of a large ferromagnetic object like a ship, was conducted. The approximate mathematical model in the form of a long cylindrical shell of constant magnetic permeability was applied. The discrete degaussing winding was assumed and the current density and magnetic flux density distribution in the ferromagnetic shell wall were determined. Based on the frequential and temporal analysis the recommended...
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Selection of Methods of Surface Texture Characterisation for Reduction of the Frequency-Based Errors in the Measurement and Data Analysis Processes
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BET (Brunauer-Emmett-Teller) surface area analysis of titanium dioxide coated nickel foams
Dane BadawczeThe data are presented for the BET surface results of nickel foams coated with titanium dioxide and heated 400, 500 and 600 degrees Celsius in an argon atmosphere. N2 sorption was performed at 77 K pore size distribution was determined by BJH and DFT methods.
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A note on fast approximate backbone coloring of split graphs with star--like backbones
PublikacjaDla grafu G = (V, E) z wyróżnionym podgrafem H, kolorowanie szkieletowe jest zdefiniowane jako odwzorowanie c spełniające |c(u) - c(v)| > 1 dla każdej krawędzi z E(H) oraz |c(u) - c(v)| > 0 dla każdej krawędzi z E(G). W pracy przedstawiono 1-przybliżony algorytm kolorowania szkieletowego split grafów ze skojarzeniem w szkielecie o złożoności O(|V|) oraz 1-przybliżony algorytm dla split grafów z rozłącznymi gwiazdami w szkielecie.
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Simulation of water flow in double -porosity soils on unstructured grids with the finite element method.
PublikacjaRozważa sie model przepływu wody w gruntowym ośrodku o podwójnej porowatości. Model matematyczny uzyskano poprzez zastosowanie teorii homogenizacji zastosowanej do gruntów o bardzo dużej różnicy przepuszczalności.
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Spectral Finite Element Method for Propagation of Elastic Waves in Wind Turbine Blades for SHM
PublikacjaW pracy przedstawiono model łopaty turbiny wiatrowej zbudowany z wykorzystaniem spektralnych elementów skończonych. Omówiono wyniki symulacji propagacji fal sprężystych i ich interakcji z uszkodzeniami w formie pęknięcia i delaminacji.
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Comparative modeling of shear zone patterns in granular bodies with finite and discrete element method
PublikacjaW artykule przedstawiono wyniki numeryczne naporu piasku na ściankę szczelną. Obliczenia wykonano stosując metodę elementów dyskretnych i skończonych na bazie mikropolarnego hipoplastycznego prawa materiałowego. Porównanie obu podejść wykonano na poziomie makro i mikro. Wyniki numeryczne porównano także z wynikami doświadczalnymi.
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Nonlocal elasticity analysis of moderately thick porous functionally graded plates in a hygro-thermal environment
PublikacjaThis work performs a novel quasi three-dimensional (3D) bending analysis for a moderately thick functionally graded material (FGM) made of nanoceramics and metal powders, in presence of porosities due to some incorrect manufacturing processes. Such porosities can appear within the plate in two forms, namely, even and uneven distributions. The modeled system assumes a polymer matrix where both shear and transverse factors coexist....
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Finite-difference analysis of a loaded hemispherical resonator
PublikacjaPrzedstawiono analizę osiowo symetrycznej struktury otwartego rezonatora he-misferycznego zawierającego warstwowe ośrodki dielektryczne. W analizie wy-korzystano metodę różnic skończonych w dziedzinie częstotliwości (FDFD). Wcelu osiągnięcia wysokiej dokładności obliczeń zastosowano zaawansowane me-tody modelowania warunków brzegowych i granicznych.
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4-Node combined shell element with semi-EAS-ANS strain interpolationsin 6-parameter shell theories with drilling degrees of freedom
PublikacjaW pracy sformułowano 4-węzłowy powłokowy element skończony klasy C0, w ramach nieliniowej 6-parametrowej teorii powłok. W celu uniknięcia zjawiska blokady (locking effect) wykorzystano technikę EAS do niesymetrycznych odkształceń membranowych i ANS do odkształceń poprzecznych.Przedstawiono przykłady potwierdzające poprawność sformułowania.
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Reliability-Based Stability Analysis of a Baltic Cliff by the Combined Response Surface Method
PublikacjaA simple, straightforward computational procedure was proposed, incorporating the Response Surface Method (RSM) linked with the standard Monte Carlo (MC) simulation method and the Point Estimate Method (PEM). PEM samples make it possible to analyse the sensitivity of the cliff’s stability to variation in subsoil parameters and to reduce the number of random variables of the problem. The proposed methods were tested in two cases:...
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Mitigating the seismic pounding of multi-story buildings in series using linear and nonlinear fluid viscous dampers
PublikacjaSeismic-induced pounding between adjacent buildings may have serious consequences, ranging from minor damage up to total collapse. Therefore, researchers try to mitigate the pounding problem using different methods, such as coupling the adjacent buildings with stiff beams, connecting them by using viscoelastic links, and installing damping devices in each building individually. In the current paper, the effect of using linear and...
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ANALYSIS OF BONE WEDGE DIMENSIONS SELECTION METHODS IN HIGH TIBIAL OSTEOTOMY
PublikacjaThe article presents the analysis of methods for selecting dimensions of bone wedge for high tibial osteotomy. The existing methods are described along with the procedure. In the following paragraphs, deficiencies in the selection of bone wedge dimensions and global trends in this field have been demonstrated. Based on the numerical analysis, the problem appearing in the wrong choice of bone wedge imensions was illustrated.
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Effects of Surface Energy and Surface Residual Stresses on Vibro-Thermal Analysis of Chiral, Zigzag, and Armchair Types of SWCNTs Using Refined Beam Theory
PublikacjaIn this article, vibration characteristics of three different types of Single-Walled Carbon Nanotubes (SWCNTs) such as armchair, chiral, and zigzag carbon nanotubes have been investigated considering the effects of surface energy and surface residual stresses. The nanotubes are embedded in the elastic substrate of the Winkler type and are also exposed to low and high-temperature environments. A new refined beam theory namely, one-variable...
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Rapid dimension scaling of compact microwave couplers with power split correction
PublikacjaIn this paper, a technique for rapid re-design ofcompact microwave couplers with respect to operating frequency is discussed. Our methodology involves an inverse surrogate model setup using several reference designs optimized (at the level of equivalent circuit representation of the coupler) for a set of operating frequencies within a range of interest. The surrogate establishes the relationship between the operating frequency...
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Comparative Analysis of Text Representation Methods Using Classification
PublikacjaIn our work, we review and empirically evaluate five different raw methods of text representation that allow automatic processing of Wikipedia articles. The main contribution of the article—evaluation of approaches to text representation for machine learning tasks—indicates that the text representation is fundamental for achieving good categorization results. The analysis of the representation methods creates a baseline that cannot...
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Methods of Functional Analysis and Topology
Czasopisma -
Methods and Objects of Chemical Analysis
Czasopisma -
On Solvability of Boundary Value Problems for Elastic Micropolar Shells with Rigid Inclusions
PublikacjaIn the framework of the linear theory of micropolar shells, existence and uniqueness theorems for weak solutions of boundary value problems describing small deformations of elastic micropolar shells connected to a system of absolutely rigid bodies are proved. The definition of a weak solution is based on the principle of virial movements. A feature of this problem is non-standard boundary conditions at the interface between the...
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Singular curves in the resultant thermomechanics of shells
PublikacjaSome geometric and kinematic relations associated with the curve moving on the shell base surface are discussed. The extended surface transport relation and the extended surface divergence theorems are proposed for the piecewise smooth tensor fields acting on the regular and piecewise regular surfaces. The recently formulated resultant, two-dimensionally exact, thermodynamic shell relations - the balances of mass, linear and angular...
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Quasilinearization methods for nonlinear differential-functional parabolic equations: unbounded case
PublikacjaRozważamy zagadnienie Cauchy'ego dla nieliniowych równań parabolicznych z zależnością funkcyjną. Przedstawiamy rezultaty dotyczące zbieżności metody quasilinearyzacji dla rozwiązań nieograniczonych.
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Implicit difference methods for nonlinear first order partial differential equations
PublikacjaW pracy klasyczne rozwiązania początkowo brzegowych problemów dla nieliniowych równań różniczkowych, szacowane są przez rozwiązania quasiliniowych układów uwikłanych równań różnicowych. Dowód zbieżności rozważanych metod opiera się na technice porównawczej z nieliniowym oszacowaniem typu Perrona dla funkcji danych. To nowe podejście do uwikłanych metod różnicowych dla równań nieliniowych opiera się na quasilinearyzacji tych metod...
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Solution of the dike-break problem using finite volume method and splitting technique
PublikacjaIn the paper the finite volume method (FVM) is presented for the solution of two-dimensional shallow water equations. These equations are frequently used to simulate the dam-break and dike-break induced flows. The applied numerical algorithm of FVM is based on the wave-propagation algorithm which ensures a stable solution and simultaneously minimizes the numerical errors. The dimensional decomposition according to the coordinate...
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Fast geometry scaling of miniaturized microwave couplers with power split correction
PublikacjaRedesigning a microwave circuit for various operating conditions is a practically important yet challenging problem. The purpose of this article is development and presentation of a technique for fast geometry scaling of miniaturized microwave couplers with respect to operating frequency. Our approach exploits an inverse surrogate model constructed using several reference designs that are optimized for a set of operating frequencies...
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Systems of Nonlinear Fractional Differential Equations
PublikacjaUsing the iterative method, this paper investigates the existence of a unique solution to systems of nonlinear fractional differential equations, which involve the right-handed Riemann-Liouville fractional derivatives D(T)(q)x and D(T)(q)y. Systems of linear fractional differential equations are also discussed. Two examples are added to illustrate the results.
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Application of discrete wavelet transform in seismic nonlinear analysis of soil–structure interaction problems
PublikacjaSimulation of soil-structure interaction (SSI) effects is a time-consuming and costly process. However, ignoring the influence of SSI on structural response may lead to inaccurate results, especially in the case of seismic nonlinear analysis. In this paper, wavelet transform methodology has been utilized for investigation of the seismic response of soil-structure systems. For this purpose, different storey outrigger braced buildings...
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Analysis of material properties of technical fabric for hanging roofs andpneumatic shells.
PublikacjaPrzedyskutowano zastosowanie w metodzie elementów skończonych specjalnego modelu elementu do analizy tkanin technicznych. Przedstawiono specjalne postępowanie z typowym elementem w płaskim w stanie naprężenia, tak aby uwzględnić można było zjawiska charakterystyczne dla tkanin technicznych. Zaproponowany model pozwala na zastosowanie niesprężystych związków konstytutywnych a w szczególności związków lepkoplastycznych. Opisano doświadczenia...
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Critical examination of benchmark problems for large rotation analysis of laminated shells
PublikacjaW pracy przedstawiono krytyczny przegląd przykładów testowych stosowanych w analizie dużych obrotów powłok warstwowych. Kilka przykładów wyselekcjonowanych z literatury zostało przeanalizowanych przy użyciu własnych programów autora bazujących na różnych poziomach nieliniowości geometrycznej. Wyniki analizy porównawczej pozwoliły na wysunięcie wniosków o przydatności badanych przykładów jako testów sprawdzających w analizie dużych...
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Fem analysis of cosserat plates and shells based on some constitutive relations
PublikacjaPrzeprowadzono studium doboru mikropolarnych współczynników konstytutywnych w pewnym modelu płyty Cosseratów. Wyznaczono ograniczenia na ich wartości i przeprowadzono parametryczną analizę wpływu tych współczynników na geometrycznie nieliniowe deformacje powłok z ortogonalnymi przecięciami płatów.
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Use of numerical methods in the analysis of traction energy systems—an overview of the practical examples
PublikacjaA characteristic feature of trolleybus transport is the random nature of traffic caused by congestion. It predestinates statistical and numerical methods for the analysis of trolleybus energy system. There are presented 3 methods of trolleybus traction system analysis: simulation of supply system based on Monte Carlo method, analysis of energy recovery potential based on statistical data analysis and benchmark of trolleybus supply...
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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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AFM visualization of Mg alloy surface modification
Dane BadawczeMagnesium alloys with additives improving their mechanical properties are valued as materials with low density and elasticity coefficient. Additionally, their biocompatibility and biodegradability make them interesting in prosthetic applications. However, the last of these features, valuable in medicine, contradicts the industrial needs for the described...
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International Journal of Nonlinear Analysis and Applications
Czasopisma -
Theory of Elasticity and Plasticity
Kursy OnlineThis course discusses the general theory of elastic and plastic material behavior of solids.
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Exact resultant equilibrium conditions in the non-linear theory of branching and self-intersecting shells
PublikacjaWe formulate the exact, resultant equilibrium conditions for the non-linear theory of branching and self-intersecting shells. The conditions are derived by performing direct through-the-thickness integration in the global equilibrium conditions of continuum mechanics. At each regular internal and boundary point of the base surface our exact, local equilibrium equations and dynamic boundary conditions are equivalent, as expected,...
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On Surface Kinetic Constitutive Relations
PublikacjaIn the framework of the strain gradient surface elasticity we discuss a consistent form of surface kinetic energy. This kinetic constitutive equation completes the statement of initial–boundary value problems. The proposed surface kinetic energy density is the most general function consistent with the constitutive relations in bulk. As the surface strain energy depends on the surface deformation gradient and its gradient, the kinetic...
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Analysis of Position Calculating Methods in Indoor Environment
PublikacjaIn the paper a modified gradient method has been proposed for position calculation on basis of distance measurement in indoor environment. It is shown that the well-known Chan method of position calculation is inefficient in indoor circumstances. Author presents Chan and modified gradient methods and achieved results for each one for real measurements.
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Two- and three-dimensional elastic networks with rigid junctions: modeling within the theory of micropolar shells and solids
PublikacjaFor two- and three-dimensional elastic structures made of families of flexible elastic fibers undergoing finite deformations, we propose homogenized models within the micropolar elasticity. Here we restrict ourselves to networks with rigid connections between fibers. In other words, we assume that the fibers keep their orthogonality during deformation. Starting from a fiber as the basic structured element modeled by the Cosserat...