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The effects of urban vehicle traffic on heavy metal contamination in road sweeping waste and bottom sediments of retention tanks
PublikacjaDiffuse pollution formed during a surface runoff on paved surfaces is a source of heavy metals (HMs) of various origin. This research study indicates the connection between bottom sediments of retention tanks located on urban streams and road sweeping wastes (RSW) that migrate during surface runoff to the stormwater drainage systems with discharge to the retention tanks. Moreover, we test the primary sources of HMs in RSW by analysing...
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Seismic Response Analysis of Knee-Braced Steel Frames Using Ni-Ti Shape Memory Alloys (SMAs)
PublikacjaShape Memory Alloys (SMAs) are known as active materials that can be widely used for structural purposes due to their flag-shape behavior under loading and reloading. Their unique characteristics provided a potential solution for civil engi-neers especially to model buildings with the capability of dissipating seismic en-ergy. In this study, the main purpose is to explore the seismic behavior of Knee-Braced Frames (KBFs) and...
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Four-node semi-EAS element in six-field nonlineartheory of shells
PublikacjaW pracy sformułowano 4-węzłowy powłokowy element skończony dla konstrukcji powłokowych. Element opracowano w ramach nieliniowej 6-parametrowej teorii powłok z niesymetrycznymi miarami odkształceń membranowych. Kinematyka powłoki jest opisana przez dwa pola: translacji i obrotów, przy czym wszystkie trzy parametry obrotu traktowane są jako niezależne. W wyniku tego sformułowany element nadaje się do analizy struktur powłokowych...
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Towards evaluation of the Second Generation Intact Stability Criteria - examination of a fishing vessel vulnerability to surf-riding, based on historical capsizing
PublikacjaThe Second Generation Intact Stability Criteria (SGISC) are the latest achievements in the field of intact ship stability assessment. The criteria are the result of massive international cooperative efforts and extensive research that lasted more than 15 years. Even though they are based on a solid scientific foundation, the trial period has commenced to collect user experience and further validation. One of possible approaches...
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Membrane shell finite element for textile fabric modelling numerical and experimental aspects
PublikacjaW pracy omówiono podstawowe problem numeryczne pojawiające się przy projektowaniu przekryć z tkanin technicznych. Przedstawiono eksperymenty potrzebne do identyfikacji właściwości mechanicznych takich tkanin.
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Sample Rate Conversion with Fluctuating Resampling Ratio
PublikacjaIn this paper a sample rate conversion with continuouslychanging resampling ratio has been presented. The proposed implementation is based on variable fractional delay filter implemented using a Farrow structure. It have been demonstrated that using the proposed approach instantaneous resampling ratio can be freely changed. This allows for simulation of audio recored on magnetic tape with nonuniform velocity as well as removal...
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Sample Rate Conversion with Fluctuating Resampling Ratio
PublikacjaIn this paper a sample rate conversion with continuously changing resampling ratio has been presented. The proposed implementation is based on variable fractional delay filter implemented using a Farrow structure. It have been demonstrated that using the proposed approach instantaneous resampling ratio can be freely changed. This allows for simulation of audio recored on magnetic tape with nonuniform velocity as well as removal...
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Zarządzanie terminowością w projektach. Wskaźniki i narzędzia
PublikacjaCzas jest istotnym elementem tzw. trójkąta projektu, dlatego też terminowość, rozu-miana, jako realizacja przedsięwzięcia w zadanym czasie, to parametr, który powinien podle-gać szczególnemu nadzorowi, a ryzyko nieterminowej realizacji powinno być wykrywane niezwłocznie. Istniejące już metody, takie jak np. wartość wypracowana (j.ang Earned Value - EV) pozwalają zaadresować te wyzwania, jednak ze względu na swoją złożoność mogą...
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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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Tailoring Graphene to Achieve Negative Poisson's Ratio Properties
PublikacjaGraphene can be made auxetic through the introduction of vacancy defects. This results in the thinnest negative Poisson's ratio material at ambient conditions known so far, an effect achieved via a nanoscale de-wrinkling mechanism that mimics the behavior at the macroscale exhibited by a crumpled sheet of paper when stretched.
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Variable Ratio Sample Rate Conversion Based on Fractional Delay Filter
PublikacjaIn this paper a sample rate conversion algorithm which allows for continuously changing resampling ratio has been presented. The proposed implementation is based on a variable fractional delay filter which is implemented by means of a Farrow structure. Coefficients of this structure are computed on the basis of fractional delay filters which are designed using the offset window method. The proposed approach allows us to freely...
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Minichannel and minigap classification criteria based on the aspect ratio of the minigeometry: A numerical study
PublikacjaA detailed numerical investigation has been carried out to analyze the diabatic flow distribution and velocity profile in 18 minigeometries with various aspect ratios for V-type and I-type flow configurations (for 36 cases) assuming ethanol as a working fluid. The aim of the study is to distinguish the value of the aspect ratio for which the flow in minigeometry starts to be two-dimensional (minigap). Cases with a constant Reynolds...
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Cylindrical orifice testing in laminar flow with the orifice diameter ratio β = 0.5
PublikacjaThe paper presents the results of an experimental study of a cylindrical orifice with the orifice diameter ratio β = 0.5 and the flow opening length‑to‑diameter ratio L/d = 1, with hydraulic oil flowing in the DN50 measuring channel. The measurements of the values characterising the oil flow were made in the laminar flow regime, for the Reynolds numbers ranging between Re = 100 to 950. Based on the experimental tests, standard...
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Ensuring the QoE-Related Fairness to Reduce the User Abandonment Ratio
PublikacjaThese days, it is quite a challenge for app owners to keep users engaged with an app. Currently, the level of user abandonment is one of the key parameters that application owners are interested in. To meet these challenges, we are conducting an extended study of a previously proposed solution that significantly reduces the abandonment rate of a given application. The investigated solution is based on the methods of fairness using...
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The role of organic and mineral constituents on kerogen transformation ratio
PublikacjaThe main aim of this dissertation is to determine the role of mineral and organic matter constituents in kerogen transformation ratio. Practical aspects of the work include application of the results in the assessment of hydrocarbon production potential; to make process of hydrocarbon recovery more predictable consistent and efficient. The work used shale from the Vaca Muerta formation from the Nequen basin in Argentina. The formation...
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Abuse or contamination? Ratio determination of clenbuterol enantiomers to distinguish between doping use and meat contamination
PublikacjaClenbuterol has been detected in urine of several athletes during routine doping control in the past years. Athletes claimed that the clenbuterol was ingested by eating contaminated meat. Providing analytical prove for this claim is difficult. clenbuterol consists of two enantiomers, R(-) and S(+)-clenbuterol. Currently available human and veterinary preparations were found to consist of a racemic mixture of both enantiomers. When...
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GPU-accelerated finite element method
PublikacjaIn this paper the results of the acceleration of computations involved in analysing electromagnetic problems by means of the finite element method (FEM), obtained with graphics processors (GPU), are presented. A 4.7-fold acceleration was achieved thanks to the massive parallelization of the most time-consuming steps of FEM, namely finite-element matrix-generation and the solution of a sparse system of linear equations with the...
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On the ratio between 2-domination and total outer-independent domination numbers of trees
PublikacjaA 2-dominating set of a graph G is a set D of vertices of G such that every vertex of V(G)D has a at least two neighbors in D. A total outer-independent dominating set of a graph G is a set D of vertices of G such that every vertex of G has a neighbor in D, and the set V(G)D is independent. The 2-domination (total outer-independent domination, respectively) number of a graph G is the minimum cardinality of a 2-dominating (total...
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A Review: Applications of the Spectral Finite Element Method
PublikacjaThe Spectral Finite Element Technique (SFEM) has Several Applications in the Sciences, Engineering, and Mathematics, which will be Covered in this Review Article. The Spectral Finite Element Method (SFEM) is a Variant of the Traditional Finite Element Method FEM that Makes use of Higher Order Basis Functions (FEM). One of the most Fundamental Numerical Techniques Employed in the Numerical Simulation is the SFEM, which Outperforms...
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Effective Formula for Impact Damping Ratio for Simulation of Earthquake-induced Structural Pounding
PublikacjaStructural pounding during earthquakes may cause substantial damage to colliding structures. The phenomenon is numerically studied using different models of collisions. The aim of the present paper is to propose an effective formula for the impact damping ratio, as a parameter of the impact force model used to study different problems of structural pounding under seismic excitations. Its accuracy has been verified by four various...
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Impact of R/X ratio of distribution network on selection and control of energy storage units
PublikacjaThe interest in energy storage is still increasing. Energy storage units are installed in high voltage networks, medium voltage networks and low voltage distribution networks as well. These units are often used to improve power quality. One of the criteria for improving power quality is reducing voltage deviations. Depending on the type of network and specifying its R/X ratio, this criterion can be fulfilled by control of active...
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Negative Poisson’s ratio from pentagons: A new auxetic structure combining three different auxetic mechanisms
PublikacjaA novel class of two-dimensional auxetic structures based on the pentagon motif is proposed. Their mechanical properties are investigated by combining molecular mechanics simulations with a simple three-parameter mechanical model which assumes perfectly elastic behavior. It is predicted that the proposed structures – termed as double re-entrant honeycomb – may possess unique mechanical characteristics, which include complete and...
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Performance of the PEM fuel cell module. Part 2. Effect of excess ratio and stack temperature
PublikacjaThe paper describes a fuel cell based system performance under different thermal conditions. The system could be fed with bottled hydrogen or with very high purity hydrogen obtained from reforming of methanol. The system is based on two fuel cell units (1.2 kW each, produced by Ballard Power Systems Inc. and called Nexa), DC/DC converter, DC/AC inverter, microprocessor control unit, load unit, bottled hydrogen supply system and...
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A Finite Element Approach for Wave Propagation in Elastic Solids
PublikacjaThis book focuses on wave propagation phenomena in elastic solids modelled by the use of the finite element method. Although the latter is a well-established and popular numerical tool used by engineers and researchers all around the word the process of modelling of wave propagation can still be a challenge. The book introduces a reader to the problem by presenting a historical background and offering a broad perspective on the...
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Wideband Macromodels in Finite Element Method
PublikacjaThis letter proposes a novel projection technique for accelerating Finite Element Method simulations. The algorithm is based on the Second-order Arnoldi Method for Passive Order Reduction (SAPOR). It involves generation of two projection bases and thanks to this it is applicable to the systems of equations, which contain the quadratic frequency-dependence in the input term, that arise when projection is applied locally in the selected...
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Modeling of pharmaceuticals mixtures toxicity with deviation ratio and best-fit functions models
PublikacjaThe present study deals with assessment of ecotoxicological parameters of 9 drugs (diclofenac (sodium salt), oxytetracycline hydrochloride, fluoxetine hydrochloride, chloramphenicol, ketoprofen, progesterone, estrone, androstenedione and gemfibrozil), present in the environmental compartments at specific concentration levels, and theirmutual combinations by couples against Microtox® and XenoScreen YES/YAS® bioassays. As the quantitative...
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Finite element matrix generation on a GPU
PublikacjaThis paper presents an efficient technique for fast generation of sparse systems of linear equations arising in computational electromagnetics in a finite element method using higher order elements. The proposed approach employs a graphics processing unit (GPU) for both numerical integration and matrix assembly. The performance results obtained on a test platform consisting of a Fermi GPU (1x Tesla C2075) and a CPU (2x twelve-core...
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PUBLIC SOURCES OF FINANCE FOR CULTURE AS AN ELEMENT OF CULTURAL SECURITY IN POLAND
PublikacjaCulture is an important element of the country, playing an important role both for its security and the economy. It cannot be only seen as a cost-creating sector, but may be a significant factor in economic development. For this to happen, it is necessary to create a system of financing this economic sector. This article’s aim is to analyze the use of funds from public sources in Poland to finance culture-related activities. The...
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Finite Element Approaches to Model Electromechanical, Periodic Beams
PublikacjaPeriodic structures have some interesting properties, of which the most evident is the presence of band gaps in their frequency spectra. Nowadays, modern technology allows to design dedicated structures of specific features. From the literature arises that it is possible to construct active periodic structures of desired dynamic properties. It can be considered that this may extend the scope of application of such structures. Therefore,...
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Evaluation of Partial Nitritation/Anammox (PN/A) Process Performance and Microorganisms Community Composition under Different C/N Ratio
PublikacjaA one-stage partial nitritation/anammox (PN/A) process with intermittent aeration is possible under sidestream conditions, but implementation in a mainstream is a challenge due to increased Carbon/Nitrogen (C/N) ratios in domestic wastewater. This study investigated the effect of C/N ratios on process efficiency and the effect of narrowing non-aeration time on process improvement at high chemical oxygen demand (COD) load. An increase...
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Modelowanie procesu wrzenia i kondensacji w rozszerzonym zakresie ciśnień zredukowanych
PublikacjaNiniejsza rozprawa doktorska ma na celu pokazanie wpływu uwzględnienia ciśnienia zredukowanego w analizowanym modelu opisują-cym współczynnik przejmowania ciepła na zbieżność z danymi eksperymentalnymi.Przedmiotem analizy jest półempiryczny model Mikielewicza w zastosowaniu do danych eksperymentalnych w kanałach konwencjonalnych i o małej średnicy płynów uznanych za perspektywiczne.W ramach realizowanych prac badawczych pozyskano...
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Optimization of Polycrystalline CVD Diamond Seeding with the Use of sp³/sp² Raman Band Ratio
PublikacjaThe influence of various nanodiamond colloids used for seeding nondiamond substrates in microwave plasma enhanced chemical vapour deposition diamond process was investigated. Colloids based on deionized water, isopropanol alcohol and dimethyl sulfoxide (DMSO) were used with different grain size dispersion: 150, 400 and 35 nm, respectively. The influence of growth time was also taken into consideration and bias enhanced nucleation....
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Impact of Low Switching-to-Fundamental Frequency Ratio on Predictive Current Control of PMSM: A simulation study
PublikacjaPredictive current control algorithms for permanent magnet synchronous (PMSM) drives rely on an assumption that within short intervals motor currents can be approximated with linear functions. This approximation may result either from discretizing the motor model or from simplifications applied to the continuous-time model. As the linear current approximation has been recognized as inaccurate in case when the drive operates with...
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The bile salt/phospholipid ratio determines the extent of in vitro intestinal lipolysis of triglycerides: Interfacial and emulsion studies
PublikacjaThis study focused on the protein-stabilised triglyceride (TG)/water interfaces and oil-in-water emulsions, and explored the influence of varying molar ratios of bile salts (BSs) and phospholipids (PLs) on the intestinal lipolysis of TGs. The presence of these two major groups of biosurfactants delivered with human bile to the physiological environment of intestinal digestion was replicated in our experiments by using mixtures...
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Reduced-order models in the finite element analysis
PublikacjaA novel technique of incorporating macromodels into finite element electromagnetic analysis of waveguide components is presented. Macromodels are generated by using a model order reduction algorithm (ENOR), which results in significant decrease of the number of variables, that describe the computational region. Proposed technique allows for using a few independent macromodels as well as to duplicating one macromodel in many subregions...
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Automatic Reduction-Order Selection for Finite-Element Macromodels
PublikacjaAn automatic reduction-order selection algorithm for macromodels in finite-element analysis is presented. The algorithm is based on a goal-oriented a posteriori error estimator that operates on low-order reduced blocks of matrices, and hence, it can be evaluated extremely quickly.
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An algorithm for enhancing macromodeling in finite element analysis of waveguide components
PublikacjaAn algorithm for enhancing the finite element method with local model order reduction is presented. The proposed technique can be used in fast frequency domain simulation of waveguide components and resonators. The local reduction process applied to cylindrical subregions is preceded by compression of the number of variables on its boundary. As a result,the finite element large system is converted into a very compact set of linear...
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Analysis of pressure ratio in the intake in dependence on high-voltage behaviours
PublikacjaPower control in spark ignition engines by regulating the intake air is performed. The control unit needs information about the air pressure conditions which then enters the combustion chamber. The information about the intake air pressure is an important quantity for optimal control of combustion mixtures. The paper describes some types of sensors that are used to measure the air intake temperature. Air pressure in the intake...
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Influence of the initial void ratio on the evolution of the passive earth pressure
PublikacjaW artykule przedstawiono wyniki numerycznej analizy wpływu rozkładu początkowego wskaźnika porowatości i fluktuacji bieżącego wskaźnika porowatości w materiałach granulowanych na powstawanie lokalizacji odkształceń. Obliczenia wykonano dla ściskania dwuosiowego stosując metodę elementów skończonych na bazie mikropolarnego prawa hipoplastycznego.
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Macromodeling techniques for accelerated finite element analysis
PublikacjaThis paper deals with the Model Order Reduction applied locally in the Finite Element Method (FEM) analysis. Due to the reduction process, blocks of FEM system matrices associated with selected subregions of the computational domain are projected onto the subspaces spanned by the vectors of suited orthogonal projection basis. In effect, large and sparse FEM matrices are replaced with small and dense ones, called macromodels. This...
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A novel formulation of 3D spectral element for wave propagation in reinforced concrete
PublikacjaThe paper deals with numerical simulations of wave propagation in reinforced concrete for damage detection purposes. A novel formulation of a 3D spectral element was proposed. The reinforcement modelled as the truss spectral element was embedded in the 3D solid spectral finite element. Numerical simulations have been conducted on cuboid concrete specimens reinforced with two steel bars. Different degradation models were considered...
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Projekt optymalnego łuku poziomego jako element nauczania kształtowania układów geometrycznych toru
PublikacjaAspekt geometryczny stanowi ważny element w nauczaniu projektowania dróg szynowych na studiach 1-go i 2-go stopnia na Wydziale Inżynierii Lądowej i Środowiska Politechniki Gdańskiej. Podstawowym, najczęściej spotykanym w praktyce elementem linii kolejowej w planie jest łuk poziomy z krzywymi przejściowymi. Z tego względu na Wydziale Inżynierii Lądowej i Środowiska Politechniki Gdańskiej wdrożono ćwiczenie projektowe ujmujące to...
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Sieć dostępowa jako element zarządzanej sieci telekomunikacyjnej
PublikacjaPrzedstawiono spojrzenie na sieć dostępową jako zarządzany przez TMN element sieci telekomunikacyjnej. Określono usługi i funkcje zarządzania siecią dostępową należące do warstwy zarządzania elementami sieci. Przedstawiono zbiór funkcji zarządzania realizowanych w instalowanych w polskiej sieci telekomunikacyjnej systemach dostępowych.
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A new finite element with variable Young's modulus
PublikacjaThe Finite Element Method (FEM) is a numerical technique that is well-established in the field of engineering. However, in biological sciences, it is justtaking its first steps. Bone tissue is an example of biological material which isexposed to high loads in its natural environment. Practically every movementof the body results in changing stress levels in the bone. Nature copes with thisvery well but when human intervention is...
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Generation of large finite-element matrices on multiple graphics processors
PublikacjaThis paper presents techniques for generating very large finite-element matrices on a multicore workstation equipped with several graphics processing units (GPUs). To overcome the low memory size limitation of the GPUs, and at the same time to accelerate the generation process, we propose to generate the large sparse linear systems arising in finite-element analysis in an iterative manner on several GPUs and to use the graphics...
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Application of polymer element in reduction of temporary steel grandstand vibrations
PublikacjaThe numerical analysis focused on reduction of vibrations of a temporary steel scaffolding grandstand has been conducted in this paper. These types of structures are regularly subjected to dynamic loads which, in conjunction with light and quite slender structural members, may induce dangerous vibrations. To increase their safety, temporary steel grandstands are usually strengthened with the diagonal stiffeners of tubular cross...
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A higher order shell element for wave propagation in isotropic shell structures
PublikacjaThe presents the new multi mode higher order shell element for wave propagation problems in shell structures.
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Geometrically nonlinear finite element simulation of smart piezolaminated plates and shells
PublikacjaW pracy zaproponowano powłokowy element skończony pozwalający na uwzględnienie efektu piezoelektrycznego. Element został wykorzystany w podejściu Lagrange'a, które wymaga starannego dobrania definicji wielkości mechanicznych i elektrycznych. Zależności przemieszczenie-odkształcenie zbudowano na bazie teorii małych odkształceń i umiarkowanych obrotów. Założono liniowy rozkład pól odkształceń i pola elektrycznego po grubości powłoki....
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Special Issue "Applications of Finite Element Modeling for Mechanical and Mechatronic Systems"
PublikacjaNumerical modeling is very important in today's engineering because, among other things, it reduces the costs associated with prototyping or predicting the occurrence of potentially dangerous situations during operation in certain defined conditions. Different methods have so far been used to implement the real structure into the numerical version. The most popular have been variations of the finite element method (FEM). The aim...
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Accuracy, Memory and Speed Strategies in GPU-based Finite-Element Matrix-Generation
PublikacjaThis paper presents strategies on how to optimize GPU-based finite-element matrix-generation that occurs in the finite-element method (FEM) using higher order curvilinear elements. The goal of the optimization is to increase the speed of evaluation and assembly of large finite-element matrices on a single GPU (Graphics Processing Unit) while maintaining the accuracy of numerical integration at the desired level. For this reason,...