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Search results for: simulational methods
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Simulation of parallel similarity measure computations for large data sets
PublicationThe paper presents our approach to implementation of similarity measure for big data analysis in a parallel environment. We describe the algorithm for parallelisation of the computations. We provide results from a real MPI application for computations of similarity measures as well as results achieved with our simulation software. The simulation environment allows us to model parallel systems of various sizes with various components...
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Simulation of the Dynamics of Renewable Energy Sources with Energy Storage Systems
PublicationThe intermittency of renewable energy sources (RES) constitutes a challenge for effective power system control. Fossil-fuel-based units offering ancillary power services to meet the short-term power imbalance are a financial and environmental burden for the society. Energy storage systems (ESS) can be the solution in view of the electricity market development and growing environmental concern. The major questions are, in what circumstances...
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Using GPUs for Parallel Stencil Computations in Relativistic Hydrodynamic Simulation
PublicationThis paper explores the possibilities of using a GPU for complex 3D finite difference computation. We propose a new approach to this topic using surface memory and compare it with 3D stencil computations carried out via shared memory, which is currently considered to be the best approach. The case study was performed for the extensive computation of collisions between heavy nuclei in terms of relativistic hydrodynamics.
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Computer Simulation in Predicting Biochemical Processes and Energy Balance at WWTPs
PublicationNowadays, the use of mathematical models and computer simulation allow analysis of many different technological solutions as well as testing various scenarios in a short time and at low financial budget in order to simulate the scenario under typical conditions for the real system and help to find the best solution in design or operation process. The aim of the study was to evaluate different concepts of biochemical processes and...
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Finite element simulation of cross shaped window panel supports
PublicationThe aim of the work is to verify suitability of cross-shaped window panel supports for mullion-transom wall systems. The Finite Element Method (FEM) is chosen to determine the behaviour of stainless steel elements under loading. The advanced non-linear numerical simulations are carried out using an implicit FEM software package MSC.Marc. This study is proposed to initiate the comprehensive investigation of mechanical properties...
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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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Probabilistic sensitivity of limit states of structures : The Monte Carlo simulation
PublicationThe main issue of the paper is the probabilistic sensitivity of the limit states of structures with respect to selected input design variables. Attempt to the problem is done by the dedicated Monte Carlo simulation procedure. Basic design variables are random variables of given probability distributions, presented in the form of random numbers. Uni-parametrical increment of the dominant basic variable (basic variables) is done,...
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Monitoring of CRT by means of impedance multiple measurements - simulation studies
PublicationCardiac resynchronization therapy (CRT) is a very promising treatment for patients with congestive heart failure. An Impedance Cardiography (ICG) is used for evaluation of heart mechanical activity. A simulation study with the use of a FEM model was performed. The developed realistic model of the thorax, based on CT data obtained from examination of a 68-year-old man, consisted of 212 000 tetrahedral elements. Different configurations...
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Mechanical model of fascia-implant structure. Finite element simulation.
PublicationPraca dotyczy modelowania i symulacji syntetycznych implantów chirurgicznych stosowanych w leczeniu przepulin brzusznych metodą laparoskowpową. Prponowane są modele matematyczne a ich prawidłowość weryfikowana jest na podstawie badań doświadczalnych zachowania się modeli fizycznych wszczepionych implantów pod wpływem obciążeń wynikających z fizjologii człowieka. Nakreślona jest metodologia oceny trwałości połączenia siatki chirurgicznej...
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Mechanical simulation of artificial gravity in torus-shaped and cylindrical spacecraft
PublicationLarge deformations and stress analyses in two types of space structures that are intended for people to live in space have been studied in this research. The structure under analysis is assumed to rotate around the central axis to create artificial gravitational acceleration equal to the gravity on the Earth's surface. The analysis is fully dynamic, which is formulated based on the energy method by using the first-order shear deformation...
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Electromagnetic Simulation with 3D FEM for Design Automation in 5G Era
PublicationElectromagnetic simulation and electronic design automation (EDA) play an important role in the design of 5G antennas and radio chips. The simulation challenges include electromagnetic effects and long simulation time and this paper focuses on simulation software based on finite-element method (FEM). The state-of-the-art EDA software using novel computational techniques based on FEM can not only accelerate numerical analysis, but...
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Simulation of Signal Propagation Along Fractional-Order Transmission Lines
PublicationIn this paper, the simulation method of signal propagation along fractional-order (FO) transmission lines is presented. Initially, fractional calculus and the model of FO transmission line are introduced. Then, the algorithm allowing for simulation of the nonmonochromatic wave propagation along FO transmission lines is presented. It employs computations in the frequency domain, i.e., an analytical excitation is transformed to the...
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Simulation of Wave Propagation in Media Described by Fractional-Order Models
PublicationIn this paper, algorithms for simulation of the wave propagation in electromagnetic media described by fractional-order (FO) models (FOMs) are presented. Initially, fractional calculus and FO Maxwell's equations are introduced. The problem of the wave propagation is formulated for media described by FOMs. Then, algorithms for simulation of the non-monochromatic wave propagation are presented which employ computations in the time...
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A Simulation Model for Risk and Pricing Competition in the Retail Lending Market
PublicationWe propose a simulation model of the retail lending market with two types of agents: borrowers searching for low interest rates and lenders competing through risk-based pricing. We show that individual banks observe adverse selection, even if every lender applies the same pricing strategy and a credit scoring model of comparable discrimination power. Additionally, the model justifies the reverse-S shape of the response rate curve....
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Transmission protocol simulation framework for the resource-constrained sensor network
PublicationIn this paper the simulation framework for simulation of the sensor network protocol is presented. The framework enables the simultaneous development of the sensor network software and the protocol for the wireless data transmission. The advantage of using the framework is the convergence of the simulation with the real software, because the same software is used in real sensor network nodes and in the simulation framework. The...
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Mathematical modelling and computer simulation of activated sludge systems.Second edition
PublicationMathematical Modelling and Computer Simulation of Activated Sludge Systems – Second Edition, provides, from the process engineering perspective, a comprehensive and up-to-date overview regarding various aspects of the mechanistic (“white box”) modelling and simulation of advanced activated sludge systems performing biological nutrient removal. In the new edition of the book, a special focus is given to nitrogen removal and an overview...
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An application of simulation investigations in design procedures of shippower system automation
PublicationPrzedstawiono wyniki prac dotyczące zastosowania badań symulacyjnych systemów energetycznych statków w środowisku programowym systemu ekspertowego. Wyniki badań symulacyjnych są źródłem głębokiej wiedzy dla systemu ekspertowego dotyczącej oceny spełnienia kryteriów towarzystw klasyfikacyjnych statków. Wybrane sesje symulacyjne podsystemu napędu głównego statku zostały przedstawione i omówione.
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Monte Carlo simulation of energy migration in uniaxially oriented polymerfilms.
PublicationOpisano zastosowanie metody Monte Carlo do symulowania (komputerowego) procesów fotofizycznych zachodzących w rozciąganych osiowo foliach polimerowych zawierających molekuły barwnika. Przedstawiono zaniki czasowe anizotropii emisji oraz jej zależność od koncentracji barwnika. Zbadano wpływ migracji energii na przebiegi anizotropii emisji badanego układu.
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Seafloor backscattering: numerical simulation vs. filter theory approach.
PublicationPrzedstawiono model opisujący rozpraszanie sygnału akustycznego na nierównomiernej, regularnie sfalowanej powierzchni dna morskiego jako filtr liniowy z odpowiedzią impulsową o zmieniającej się w czasie chwilowej dominującej częstotliwości. Porównano przewidywania modelu z wynikami otrzymanymi w wyniku złożonych obliczeniowo symulacji numerycznych opartych na fizycznym modelu zjawiska wykorzystującym aproksymację Kirchhoffa. Wstępnie...
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Simulation of solid state ionic conductors I-V characteristics
PublicationW pracy przedstawiono sumulacje charakterystyk prądowo-napięciowych czujników elktrokatalitycznych. Zastosowano metode różnić skończonych.
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The numerical simulation of two-dimensional vertical incompressible viscous flow
PublicationW artykule przedstawiono numeryczne symulacje płaskiego pionowego przepływu nieściśliwej cieczy lepkiej ze swobodną powierzchnią. Zastosowano model bazujący na rozwiązaniu równań Naviera-Stokesa metodą "ciśnień" (SIMPLE). Przy takim podejściu otrzymano dywergencję równań Naviera-Stokesa oraz równanie Poissona na ciśnienie. W rozwiązaniu zastosowano schemat Laxa-Wendroffa z przesuniętą siatką Eulera. Takie podejście zapewnia dokładność...
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Design framework and simulation investigation of cellular parts manufacturing applications
PublicationPrzedstawiono koncepcję projektowania przebiegów grupowego wytwarzania asortymentu przedmiotów w systemach typu przepływowego, z wykorzystaniem algorytmu analizy podobieństwa ciągów znakowych, reprezentujących marszruty procesów, i jego oceny wg kryterium odległości Levenshteina, zgodnie z paradygmatem oszczędnej produkcji. Efektywność proponowanej metodyki weryfikowano symulacyjnie wg określonych scenariuszy, opisujących wariantowe...
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Przegląd metod oznaczania pozostałości pestycydów i polichlorowanych bifenyli w próbkach żywności = Methods of determination of residues of pesticides and polychlorinated biphenyls in food samples - a review
PublicationOznaczanie pozostałości pestycydów i analitów z grupy polichlorowanych bifenyli w próbkach żywności wymaga zastosowania specyficznych technik w zakresie przygotowania próbki do analizy, jak i samych technik analizy instrumentalnej, pozwalających na uzyskanie bardzo niskiej granicy oznaczalności. Problemem związanym ze stosowaniem związków z grupy pestycydów i polichlorowanych bifenyli jest konieczność kontroli ich pozostałości...
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Analiza porównawcza metod predykcji chwili zgodności fazowejw automatycznym synchronizatorze prądnic = Comparison of the methods of prediction time phase coincidence in automatic synchronizer of power generators
PublicationW artykule porównano dokładność wybranych metod realizacji warunku fazowego podczas synchronizacji obiektów elektroenergetycznych. Do porównania wybrano trzy metody: liniową, wielomianową oraz metodę adaptacyjnej synchronizacji prądnic z ekstrapolacją funkcją wymierną. Badania przeprowadzono dla różnych warunków pracy. Przyjęto stałą różnicę częstotliwości napięć synchronizowanych obiektów, różnicę częstotliwości zmieniającą się...
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Zastosowanie metody równań całkowych w analizie pola ekranującego obiektów ferromagnetycznych.Application of integral equations method to shield field analysis of ferromagnetic object.
PublicationDuże obiekty ferromagnetyczne, jakimi są okręty, powodują zaburzenia w rozkładzie ziemskiego pola ma-gnetycznego. Dla zredukowania tego zaburzenia na okrętach umieszcza się specjalne uzwojenia, których ce-lem jest wytworzenie pola magnetycznego usuwającego zmiany wywołane obecnością ferromagnetyka w zewnętrznym polu ziemskim. Obliczania rozkładu tych uzwojeń wiąże się z koniecznością znalezienia rozkładu pola magnetycznego.Zastosowanie...
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From flow to jamming: Lattice Gas Automaton simulations in granular materials
PublicationWe introduce the first extension of a Lattice Gas Automaton (LGA) model to accurately replicate observed emergent phenomena in granular materials with a special focus on previously unexplored jamming transitions by incorporating gravitational effects, energy dissipation in particle collisions, and wall friction. We successfully reproduce flow rate evolution, density wave formation, and jamming transition observed in experiments....
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Hydration of N-Hydroxyurea from Ab Initio Molecular Dynamics Simulations
PublicationN-Hydroxyurea (HU) is an important chemotherapeutic agent used as a first-line treatment in conditions such as sickle cell disease and β-thalassemia, among others. To date, its properties as a hydrated molecule in the blood plasma or cytoplasm are dramatically understudied, although they may be crucial to the binding of HU to the radical catalytic site of ribonucleotide reductase, its molecular target. The purpose of this work...
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Simulations of air and water flow in a model dike during overflow experiments
PublicationFlow in flood dikes, earth dams, and embankments occurs in variably saturated conditions, with pores of the earth material filled partly with water and partly with air. In routine engineering analysis, the influence of pore air is neglected and the air pressure is assumed equal to atmospheric. In some circumstances, for example, during overtopping of the dike by water, the effect of pore air on water flow and stability of the structure...
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Application of advanced CFD simulations in seakeeping analysis of ships (case study)
PublicationThe novel design process of many types of ships needs estimation of seakeeping properties. Especially ships like Offshore Supply Vessels, Wind Farm Support Vessels, Research Vessels, ferries, military vessels, rescue vessels require extended analysis of ship behavior on rough sea. The main reason for improving ships operability in different sea conditions is need of rising efficiency of propulsion system, reducing hull added resistance,...
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Static Load Test on Instrumented Pile – Field Data and Numerical Simulations
PublicationFor some time (since 8-10 years in Poland) a special static load tests on instrumented piles are carried out. Such studies are usually of a scientific nature and provide detailed quantitative data on the load transfer into the ground and characteristics of particular soil layers interaction with a pile shaft and pile base. Deep knowledge about the pile-subsoil interaction can be applied for a various design purposes, e.g. numerical...
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Keep It Flexible: Driving Macromolecular Rotary Motions in Atomistic Simulations with GROMACS
PublicationWe describe a versatile method to enforce the rotation of subsets of atoms, e.g., a protein subunit, in molecular dynamics (MD) simulations. In particular, we introduce a “flexible axis” technique that allows realistic flexible adaptions of both the rotary subunit as well as the local rotation axis during the simulation. A variety of useful rotation potentials were implemented for the GROMACS 4.5 MD package. Application to the...
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RMS-based damage detection in reinforced concrete beams: numerical simulations
PublicationImage-based damage detection methods using guided waves are well known and widely applied approaches in structural diagnostics. They are usually utilized in detection of surface damages or defects of plate-like structures. The article presents results of the study of applicability of imaging wave-based methods in detection in miniscule internal damage in the form of debonding. The investigations were carried out on numerical models...
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Separation of variables in molecular-dynamics simulations: A criterion to estimate the quality of the approximation
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Star Polymers vs. Dendrimers: Studies of the Synthesis Based on Computer Simulations
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Numerical simulations of space-time conditional random fields of ground motions
PublicationArtykuł przedstawia metodę modelowania stochastycznego efektu propagacji fali sejsmicznej z wykorzystaniem przestrzenno-czasowej funkcji korelacji pola losowego trzęsienia ziemi. Metodę wykorzystano do generacji nieznanych historii czasowych trzęsienia w wybranych punktach na podstawie znanego rejestru w jednym miejscu. Wyniki pokazały, iż zastosowanie zaproponowanej metody prowadzi do relatywnie małych błędów symulacji.
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Verification of geotechnical numerical simulations by model tests using PIV technique
PublicationPrzedstawiono metodykę i wyniki badań modelowych stateczności fundamentów bezpośrednich posadowionych w sąsiedztwie kątowych ścian oporowych. Dla takiego złożonego układu fundament - obciążenie - podłoże gruntowe wykonano badania modelowe w płaskim stanie odkształcenia na gruncie naturalnym i analogowym. Trajektorie i izopola przemieszczeń oraz progresywny rozwój kształtu i zasięgu powierzchni poślizgu określono techniką PIV.
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Implementing Simulationx in the Modelling of Marine Shafting Steady State Torsional Vibrations
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Molecular dynamics simulations of the growth of poly(chloro-para-xylylene) films
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Modelling of soft fault propagation in sequential circuits by fuzzy-logic simulations
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Numerical simulations of transonic flow with film cooling and jet vortex generators
PublicationW pracy przedstawiono wyniki obliczeń przepływu transonicznego na stronie ssącej łopatki turbiny gazowej. Obliczenia wykonano dla geometrii komory pomiarowej w tunelu transonicznym IMP PAN, zaprojektowanej tak, aby odwzorować warunki przepływowe istniejące w palisadzie turbinowej. Przedstawiono wyniki obliczeń przepływu z zastosowaniem otworów chłodzących (film cooling) oraz strumieniowych generatorów wirów. Porównano je z danymi...
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Molecular dynamics simulations of the growth of poly (chloro-para-xylylene) films.
PublicationParylene C, poly(chloro-para-xylylene) is the most widely used member of the parylene family due to its excellent chemical and physical properties. In this work we analyzed the formation of the parylene C film using molecular mechanics and molecular dynamics methods. A five unit chain is necessary to create a stable hydrophobic cluster and to adhere to a covered surface. Two scenarios were deemed to take place. The obtained results...
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FDTD Simulations on Disjoint Domains with the Use of Discrete Green's Function Diakoptics
PublicationA discrete Green's function (DGF) approach to couple disjoint domains in the finite-difference time-domain (FDTD) grid is developed. In this method, total-field/scattered-field (TFSF) FDTD domains are associated with simulated objects whereas the interaction between them is modeled with the use of the DGF propagator. Hence, source and scatterer are simulated in separate domains and updating of vacuum cells, being of little interest,...
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Situational Awareness Network for the Electric Power System: the Architecture and Testing Metrics
PublicationThe contemporary electric power system is highly dependent on Information and Communication Technologies which results in its exposure to new types of threats, such as Advanced Persistent Threats (APT) or Distributed-Denial-of-Service (DDoS) attacks. The most exposed components are Industrial Control Systems in substations and Distributed Control Systems in power plants. Therefore, it is necessary to ensure the cyber security of...
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Membrane model of human abdominal wall. Simulations vs. in vivo measurements
PublicationThe study presents a methodology of defining a numerical model of human abdominal wall based on the experimentally registered data of the abdomen geometry due to variations of the intraabdominal pressure. The abdominal wall is modelled here as a simple homogeneous membrane structure made of linear orthotropic material The displacements registered during the increase of pressure are compared with the re-sults of the model static...
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A simplified behavioral MOSFET model based on parameters extraction for circuit simulations.
PublicationThe paper presents results on behavior modeling of general purpose Metal-Oxide Semiconductor Field-Effect Transistor (MOSFET) for simulation of power electronics systems requiring accuracy both in steady-state and in switching conditions. Methods of parameters extraction including nonlinearity of parasitic capacitances and steady-state characteristics are based on manufacturer data sheet and externally measurable characteristics....
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Towards an efficient multi-stage Riemann solver for nuclear physics simulations
PublicationRelativistic numerical hydrodynamics is an important tool in high energy nuclear science. However, such simulations are extremely demanding in terms of computing power. This paper focuses on improving the speed of solving the Riemann problem with the MUSTA-FORCE algorithm by employing the CUDA parallel programming model. We also propose a new approach to 3D finite difference algorithms, which employ a GPU that uses surface memory....
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Constant vs. Variable Efficiency of Electric Drive in Train Run Simulations
PublicationTrain run simulations, which focus on various power- and energy-oriented aspects, should reflect the losses in the electric powertrain. In general, the powertrain efficiency varies with respect to load and speed. Including this relation in simulation requires knowledge about detailed drivetrain parameters, which are often unavailable. This paper verifies the possibility to approximate the drivetrain efficiency in train run simulations...
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Improvement of ships seakeeping performance by application of the full-scale cfd simulations
PublicationThe ship’s fuel economy is increasingly important. The paper presents the effect of redesigning a case study ship for increasing seakeeping performance. Selected wave parameters reflect very difficult operational conditions existing on the North Sea and the Baltic Sea. The analyzed variants of a case study ship represent the latest developments of modern hull forms. The concepts similar to V-shaped bulbous bow, X-bow, X-aft, B-bow...
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Discussion on “Coupled effective stress analysis of insertion problems in geotechnics with the Particle Finite Element Method” by L. Monforte, M. Arroyo, J.M. Carbonell, and A. Gens
PublicationAddressed here is the Particle Finite Element Method (PFEM) modelling of undrained CPTu penetration with regard to a reference analytical solution based on the Spherical Cavity Expansion Method (SCEM). Also discussed is the choice of the soil model and its parameters. The effect of cone interface friction on CPTu simulation is analyzed in a series of penetration tests using Arbitrary Lagrangian-Eulerian (ALE) and Updated Lagrangian...
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Diagnostyka łożysk silnika indukcyjnego poprzez analizę prądu silnika metodą NTC. Część I – opis zastosowanej metody
PublicationW artykule zaprezentowano nową metodę przetwarzania sygnału prądu silnika indukcyjnego do celów diagnostyki łożysk oraz jej walidację przy pomocy badań eksperymentalnych. Badania przeprowadzono dla trzech różnych uszkodzeń łożysk przy pełnym obciążeniu silnika. Pierwsza część artykułu zawiera wprowadzenie do tematyki diagnostyki łożysk, przegląd metod diagnostycznych oraz podstawy teoretyczne zastosowanej przez autora metody. W...