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Search results for: numerical%20models
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Numerical analysis of high temperature minichannel heat exchanger for recuperative microturbine system
PublicationConsidering the development of energy sector, distributed small-scale power generation, e.g., gas micro-CHP, is attracting considerable interest. In such installations, the heat exchanger is one of the key components possessing a significant influence on overall performance. Most studies concentrate on units operating below 900C, which do not fulfil the requirements of gas micro-CHP. Therefore, there remains a challenge to design...
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Numerical investigation into plastic hinge formation in arched corrugated thin-walled profiles
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Advanced numerical modelling for predicting residual compressive strength of corroded stiffened plates
PublicationAn advanced methodology for predicting the residual compressive strength of corroded stiffened plates is developed here using the non-linear finite element method. The non-uniform loss of a plate thickness is accounted for on a macro-scale. In contrast, mechanical properties are changed using the constitutive model to reflect the corrosion degradation impact on a micro-scale. Three different stiffened plate thicknesses are considered,...
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Experimental Validation of Numerical Model within a Flow Configuration of the Model Kaplan Turbine
PublicationThis paper investigates validation of flow within a model Kaplan turbine. This includes comparison of various turbulence models and their influence on torque and power generated by the turbine. Numerical results were compared with experimental data.
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Determination of model's fixing boundary conditions for the numerical simulations of the dynamic experimental tests
PublicationZaprezentowano badania eksperymentalne oraz ich symulacje numeryczne przeprowadzone na płytach obciążanych impulsowo (wybuch mieszanki gazowej). Głównym obszarem zainteresowania pracy jest wyznaczenie warunków brzegowych w stosowanym modelu.
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Advanced coating of interior of tanks for rising environmental safety - numerical simulation of grounding
PublicationZwiększanie bezpieczeństwa środowiska naturalnego podczas transportu materiałów ropopochodnych stale stanowi ważny i aktualny problem badawczy. W pracy prezentowane są wyniki badań innowacyjnych powłok ochronnych zmniejszających ryzyko rozlewu olejowego podczas kolizji środków transportu - w szczególności statków. Prace badawcze prowadzone były w ramach programu Eureka E!3614 CORET.
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Response of high voltage disconnector under seismic excitation - experimental and numerical study
PublicationThe efficiency of the energetic infrastructure system is a very import safety issue in the region experienced by the ground motion. The aim of the present paper is to show the results of the experimental and numerical study focused on the earthquake-induced response of the high voltage disconnector, which is an important element of energetic network. First, the impact tests as well as the sweep-sine shaking table tests were conducted....
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Historical carpentry corner log joints—Numerical analysis within stochastic framework
PublicationThe paper presents the results of numerical analysis performed on historical, traditional carpentry corner logjoints of two basic topologies: the short-corner dovetail connection and the saddle notch connection. These types of carpentry joints are commonly used in currently preserved objects of wooden architecture. All connections have been modelled in pinewood, which has been defined in the Finite Element software MSC.Marc/Mentat...
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VALUATION OF EMBEDDED OPTIONS IN NON-MARKETABLE CALLABLE BONDS: A NEW NUMERICAL APPROACH
PublicationThe issue of how to price options embedded in callable bonds has attracted a lot of interest over the years. The usual bond valuation methods rely on yield curves, risk premium, and other parameters to estimate interest rates used in discounted cash flow calculations. The option to retire the bond is, however, neglected in the standard pricing models, causing a systematic overvaluation of callable bonds. In the event of a decline...
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Numerical simulation of temperature distribution of heat flow on reservoir tanks connected in a series
PublicationThe flow of temperature distribution through a medium in thermodynamic studies plays an important role in understanding physical phenomena in chemical science and petroleum engineering, while temperature distribution indicates the degree of reaction that must be undergone to obtain the final product. Therefore, this paper aims to present and apply the exponential matrix algorithm (EMA), differential transformation algorithm (DTA),...
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Experimental-Numerical Analysis of the Effect of Bar Diameter on Bond in Pull-Out Test
PublicationBar diameter is one of the basic factors affecting bond behavior, which is still of interest due to opposing opinions regarding its effect on bond behavior in the pull-out test. This paper presents an experimental and numerical bond analysis of ribbed reinforcing bar in concrete. The aim was to experimentally evaluate the effect of bar diameter on the bond behavior in the pull-out test and to perform numerical simulations of the...
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Experimental and Numerical Study on Mechanical Characteristics of Aluminum/Glass Fiber Composite Laminates
PublicationThe fiber-metal composites made of aluminum sheets and glass fibers reinforced with a polyester resin as the matrix were studied. The composites were prepared by hand lay-up method. Some aspects of manufacturing affecting the composite behavior were considered. In particular, the influences of the arrangement of layers and their number on the mechanical and physical properties of composites with ten different compositions were...
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On numerical analysis of a thin-walled I-beam with warping stiffenes undertorsional loads
PublicationPraca jest streszczeniem referatu wygłoszonego na międzynarodowej konferencji Metody Komputerowe w Mechanice, Wisła, 3-6 czerwca 2003. Przedstawiono problem numerycznej analizy belek cienkościennych ze stężeniami. Omówiono dwa modele jednowymiarowe: jeden bazujący na koncepcji skupionej sztywności bimomentowej, a drugi na zastosowaniu superelementu MES. Otrzymane wyniki porównano z rezultatami analizy MES przy zastosowaniu dyskretyzacji...
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Numerical analysis of a test embankment on soft ground using an anisotropic model with destructuration
PublicationPrzeprowadzono analizę numeryczną konsolidacji podłoża słabonośnego pod obciążeniem próbnego nasypu drogowego metodą elementów skończonych. Zachowanie się gruntu słabonośnego zamodelowano przy użyciu nowego modelu konstytutywnego typu multi-laminate uwzględniającego anizotropię wytrzymałości oraz zjawisko destrukturyzacji. Wyniki obliczeń porównano z pomiarami polowymi.
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Some remarks about numerical stability in nonlinear dynamics on the basic of truss structures.
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Particulate organic carbon in the southern Baltic Sea: numerical simulations and experimental data
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Experimental and numerical study on spontaneous ignition of hydrogen and hydrogen-methane jets in air
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Numerical Simulations of DDT Limits in Hydrogen-Air Mixtures in Obstacle Laden Channel
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Numerical simulation of damage detection in rectangular plate by two-dimensional wavelet transform.
PublicationW pracy przedstawiono metodę lokalizacji pęknięć w płytach przy zastosowaniu transformaty falkowej.
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The computer numerical control system with permanent magnet synchronous motor servo-drives.
PublicationPrzedstawiono układ serwonapędów wieloosiowej maszyny sterowanej numerycznie. W układzie wykorzystano silniki synchroniczne z magnesami trwałymi oraz procesory synałowe DSP. Omówiono algorytmy sterowania nadrzędnego oraz problemy sterownia silnika PMSM.
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Numerical simulations of transverse pounding-involved response of buildings due to earthquake excitation.
PublicationCelem artykułu jest analiza (w kierunku poprzecznym) zachowania się uderzających o siebie budynków podczas trzęsienia ziemi. W analizie tej obie konstrukcje modelowane są przy użyciu dyskretnego, sprężysto-plastycznego modelu o skupionych masach, zaś do symulacji zderzeń zastosowano nieliniowy model lepko-sprężysty. Wyniki analizy pokazują, iż zderzanie prowadzi do znacznego wzrostu odpowiedzi w kierunku poprzecznym dla konstrukcji...
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Numerical calculation of three-phase transformer's residual flux in ATP and PSpice programs.
PublicationW artykule przedstawiono analizę przebiegów prądu i strumienia magnetycznego podczas wyłączania transformatora energetycznego, wykonaną w celu określenia strumieni szczątkowych. Wykorzystano do tego celu modele obwodowe zbudowane w oparciu o programy symulacyjne ATP (Alternative Transients Program) i PSpice. Wyniki obliczeń okazały się bardzo zbliżone dla obu modeli. Przy ich wykorzystaniu obliczono strumienie szczątkowe w kolumnach...
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Statistical description and numerical calculations of cylindrical vertical tanks with initial geometric imperfections
PublicationDokonano identyfikacji rzeczywistych wstępnych imperfekcji geometrycznych stalowych pionowych zbiorników walcowych. Imperfekcje przedstawiono jako pole losowe opisane za pomocą odpowiednio dobranej funkcji korelacyjnej, wartości oczekiwanej oraz obwiedni pola. Wykorzystując własne programy numeryczne przeprowadzono generację zbioru odchyłek geometrycznych zbiornika. Porównano estymatory wygenerowanego pola losowego z parametrami...
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Numerical method of lines for first order partial differential equations with deviated variables
PublicationPraca traktuje o przybliżaniu rozwiązań klasycznych równańróżniczkowo-funkcyjnych cząstkowych pierwszego rzędu rozwiązaniamiukładów quasiliniowych równań różnicowych. Nowe podejście dorozwiązywania równań nieliniowych zawdzięczamy metodziequasilinearyzacji dla zagadnień początkowo - brzegowych z odchylonymargumentem. Dla przyrostów pochodnych funkcji danej zakładamy nieliniowe oszacowanie typu Perrona. Załączone są wyniki eksperymentów...
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Particle Shape Effect on Macroscopic Behaviour of Underground Structures: Numerical and Experimental Study
PublicationAbstract: The mechanical performance of underground flexible structures such as buried pipes or culverts made of plastics depend not only on the properties of the structure, but also on the material surrounding it. Flexible drains can deflect by 30% with the joints staying tight, or even invert. Large deformations of the structure are difficult to model in the framework of Finite Element Method, but straightforward in Discrete...
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Numerical modeling of the combustion in a lab-scale pulverized-coal fired combustion chamber
PublicationThis work presents results of numerical modeling of the combustion process inside a lab-scale drop-tube chamber, designed to investigate the slagging properties of the flue ashes, created through the solid fuel firing. Interaction between turbulence and chemistry is accounted by use of probability density function (PDF). FLUENT inputs for non-premixed combustion chemistry modeling are defined. A discrete second phase of the coal...
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Earthquake–induced pounding on response of adjacent structures in series: experimental and numerical study
PublicationPounding between structures in series during earthquakes may cause serious damage in the structur-al elements. The aim of this paper is to show the results of an experimental and numerical study that is focused on pounding between more than two structures which may be called "structures in series". In this study, the shaking table experiments, as well as the numerical analyses, were performed using three tower models including...
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Numerical Analysis of Impact of Energy Buoy Anchoring Configurations on its Motion and Efficiency
PublicationThis paper presents a numerical analysis of the impact of energy buoy mooring configurations on its movement on the wave and effectiveness. The method used to analyse the buoy movement modelling in six degrees of freedom was described in a paper presented at the Conference 2011. Simulations of the buoy movement in regular wave and power calculations were conducted for several configurations of anchoring systems and position of...
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EXPERIMENTAL AND NUMERICAL STUDY ON COLLISIONS BETWEEN STEEL STRUCTURES UNDER EARTHQUAKE EXCITATION
PublicationIn the time of high urbanization, the need to build closely-spaced structures forces the designers to take into account earthquake-induced collisions between adjacent buildings and their effects on the response of structures. Past and recent investigations confirmed that interactions between adjacent buildings during earthquakes may cause serious damages to the structural elements and may even lead to total collapse of the structure....
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On Nonlinear Bending Study of a Piezo-Flexomagnetic Nanobeam Based on an Analytical-Numerical Solution
PublicationAmong various magneto-elastic phenomena, flexomagnetic (FM) coupling can be defined as a dependence between strain gradient and magnetic polarization and, contrariwise, elastic strain and magnetic field gradient. This feature is a higher-order one than piezomagnetic, which is the magnetic response to strain. At the nanoscale, where large strain gradients are expected, the FM effect is significant and could be even dominant. In...
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Effect of Flow Normalization in Micro-Pin-Finned Heat Sink: Numerical Study
PublicationThe micro-pin-fin heat sink (MPFHS) is widely employed for the heat transfer enhancement of microchannel heat sinks. In the current paper, the effect of flow normalization on the thermohydraulic performance of micro-pin-finned heat sinks is studied numerically. Two geometries of MPFHSs, the conventional design micro-pin-fin heat sink (CD-MPFHS) with a uniform-width micro pin fin and the proposed design micro-pin-fin heat sink (PD-MPFHS)...
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Nonlinear numerical simulation of earthquake-induced pounding between timber frame buildings
PublicationEarthquakes may induce serious dynamic loads acting on buildings, which can lead to damage or even destruction of the whole structure. In densely populated areas, it is quite common that buildings are located very close one to another which can result in pounding between them during ground motions. Due to the environmental awareness, multi-story timber frame buildings are gaining popularity and therefore there is a need to investigate...
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Experimental and numerical investigations of ultimate strength of imperfect stiffened plates of different slenderness
PublicationThe objective of this study is to analyse the behaviour of compressed stiffened plates of different slenderness using experimental and numerical methods. The presented results are part of a long-term project to investigate the ultimate strength of geometrically imperfect structures subjected to different degradation phenomena, including corrosion degradation and locked cracks. Several specimens were subjected to a uniaxial compressive...
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Experimental and Numerical Investigation of Tensile and Flexural Behavior of Nanoclay Wood-Plastic Composite
PublicationIn this study, the effect of wood powder and nanoclay particle content on composites’ mechanical behavior made with polyethylene matrix has been investigated. The wood flour as a reinforcer made of wood powder was at levels of 30, 40, and 50 wt.%, and additional reinforcement with nanoclay at 0, 1, 3, and 5 wt.%. Furthermore, to make a composite matrix, high-density polyethylene was used at levels of 70, 60, and 50% by weight....
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Numerical Modeling and Simulation of Vehicular Crashes into Three-Bar Metal Bridge Rail
PublicationAdvanced finite element (FE) modeling and simulations were performed on vehicular crashes into a three-bar metal bridge rail (TMBR). The FE models of a sedan, a pickup truck, and a TMBR section were adopted in the crash simulations subject to Manual for Assessing Safety Hardware (MASH) Test Level 2 (TL-2) and Test Level 3 (TL-3) requirements. The test vehicle models were first validated using full-scale physical crash tests conducted...
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Numerical study on pounding between two adjacent buildings under earthquake excitation
PublicationSeismic excitation, which results in large horizontal relative displacements, may cause collisions between two adjacent structures due to insufficient separation distance between them. Such collisions, known as earthquake-induced structural pounding, may induce severe damages. In this paper, the case of pounding between two adjacent buildings is studied by the application of single degree-of-freedom structural models. Impact is...
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The Influence of Selected Parameters of Numerical Modelling on Strains and Stresses at Weld Toe Notch
PublicationLatest development in the field of welding technology and prefabrication enabled massive production of thin-walled sandwich structures. Multi-layered sandwich structures are fabricated with the use of high-power CO2 lasers, friction welding, arc welding, hybrid welding, or other technique designed for the special purpose. Steel or aluminium alloy plates with thickness between 1 and 5 mm are connected by internal stiffeners. Strength...
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Turbulence model evaluation for numerical modelling of turbulent flow and heat transfer of nanofluids
PublicationIn this work, Nusselt number and friction factor are calculated numerically for turbulent pipe flow (Reynolds number between 6000 and 12000) with constant heat flux boundary condition using nanofluids. The nanofluid is modelled with the single-phase approach and the simulation results are compared with experimental data. Ethylene glycol and water, 60:40 EG/W mass ratio, as base fluid and SiO2 nanoparticles are used as nanofluid...
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Numerical modeling of the combustion in a lab-scale pulverized-coal fired combustion chamber
PublicationThis work presents results of numerical modeling of the combustion process inside a lab-scale drop-tube chamber, designed to investigate the slagging properties of the flue ashes, created through the solid fuel firing. Interaction between turbulence and chemistry is accounted by use of probability density function (PDF). FLUENT inputs for non-premixed combustion chemistry modeling are defined. A discrete second phase of the coal...
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Constitutive Modelling of Knitted Abdominal Implants in Numerical Simulations of Repaired Hernia Mechanics
PublicationThe paper presents a numerical approach to describe mechanical behavior of anisotropic textile material, which is a selected abdominal prosthesis. Two constitutive nonlinear concepts are compared. In the first one the material is considered composed from two families of threads (dense net model) and in the second one the material is homogeneous but anisotropic (as proposed by Gassel, Ogden, Holzapfel). Parameters of both models...
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Experimental and Numerical Investigation of Mechanical Properties of Lightweight Concretes (LWCs) with Various Aggregates
PublicationHigh requirements for the properties of construction materials and activities directed at environment protection are reasons to look for new solutions in concrete technology. This research was directed at solutions affecting the reduction of energy consumption and CO2 emissions. The use of lightweight concretes (LWCs) allows one to meet both conditions at the same time. The purpose of the research presented in this paper was to...
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Space-Time Conservation Method applied to numerical solution of water hammer equations
PublicationArtykuł poświęcony jest metodzie czasoprzestrzennych objętości skończonych (STC) zastosowanej do przypadku uderzenia hydraulicznego w stalowym przewodzie pracującym pod ciśnieniem. Metoda STC ze względu na swoje własności numeryczne - m.in. wysoką dokładność - może być interesującą alternatywą dla tradycyjnych metod numerycznych, szczególnie w przypadku, gdy efekty numeryczne mają bardzo silny wpływ na rozwiązanie, tym samym utrudniając...
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Numerical methods for nonlinear first-order partial differential equations with deviated variables
PublicationKlasyczne rozwiązania zagadnień początkowych dla nieliniowych równań cząstkowych z odchylonym argumentem aproksymowano za pomocą rozwiązań układów quasiliniowych równań różnicowych określonych na piramidzie Haara. Podano warunek dostateczny zbieżności metody. Stabilność schematu różnicowego wykazano metodą porównawczą. Przedstawiono metodę rozwiązywania nieliniowych równań różniczkowych cząstkowych z odchylonym argumentem bazującą...
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Numerical modelling of asymetric double-layer Al-Cu plate rolling process
PublicationNiekorzystnym zjawiskiem towarzyszącym procesom walcowania płaskich wyrobów bimetalowych jest krzywizna pasma na wyjściu z kotliny walcowniczej wynikająca z nierównomierności odkształcenia warstw bimetalowej blachy. Możliwość szybkiego i łatwego przeciwdziałania temu zjawisku daje wprowadzenie asymetrii prędkości bądź średnic walców roboczych. W przedstawionym artykule zaprezentowano badania komputerowe procesu walcowania blach...
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Numerical simulations of the influence of injection moulding parameters on mechanical properties of the polyamide composite
PublicationZaprezentowano wyniki symulacji numerycznej wpływu parametrów technologicznych procesu wtryskiwania na wybrane właściwości mechaniczne kompozytu poliamidowego. Symulacje przeprowadzono z wykorzystaniem programu Cadmould-3d.
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Numerical Analyses of Fracture Mechanism of the Pelvic Ring during Side-Impact Load
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Numerical analysis of the container vessel's self-propulsion at different rudder deflection angles
PublicationNowadays, CFD becomes one of the most commonly used research method in ship hydrodynamics, limited to the analyses of hull resistance in calm water. With continuously improving computing power and increasingly more accurate numerical methods it is possible to simulate more complex cases. State of the art CFD tools also enable development of new ways of assessing ship maneuvering performance. This paper presents an attempt on...
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THE TIMING OF INITIAL PUBLIC OFFERINGS – NON-NUMERICAL MODEL BASED ON QUALITATIVE TRENDS
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Numerical modelings of ultrashort pulse propagation and conical emission in multimode optical fibers
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Numerical simulation of the quaternary aquifer groundwater flow of the northern Vistula delta plain
PublicationW pracy przedstawiono wyniki obliczeń krążenia wód podziemnych w czwartorzędowym poziomie wodonośnym rejonu Żuław Gdańskich. Czwartorzędowy poziom wodonośny odgrywa najważniejszą rolę w zaopatrzeniu w wodę aglomeracji gdańskiej. W obliczeniach wykorzystano programy Modflow i Modpath zawarte w pakiecie (GMS 3.1). Odtworzono warunki przed uruchomieniem ujecia Lipce wykorzystując obliczenia dla stanu ustalonego krążenia wody w warstwie...