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wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: IRREGULAR BRIDGE, NONLINEAR TIME HISTORY ANALYSIS, STRUCTURAL POUNDING, SEISMIC EXCITATION, GAP SIZE, INTENSITY MEASURE
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Excitation of Non-Wave Modes by Sound of Arbitrary Frequency in a Chemically Reacting Gas
PublikacjaThe nonlinear phenomena in the field of high intensity sound propagating in a gas with a chemical reaction, are considered. A chemical reaction of A → B type is followed by dispersion and attenuation of sound which may be atypical during irreversible thermodynamic processes under some conditions. The first and second order derivatives of heat produced in the chemical reaction evaluated at the equilibrium temperature, density and...
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Determination of Thermophysical Parameters Involved in The Numerical Model to Predict the Temperature Field of Cast-In-Place Concrete Bridge Deck
PublikacjaThe paper dealswith a concept of a practical computationmethod to simulate the temperature distribution in an extradosed bridge deck. The main goal of the study is to develop a feasible model of hardening of concrete consistent with in-situ measurement capabilities. The presented investigations include laboratory tests of high performance concrete, measurements of temperature evolution in the bridge deck and above all, numerical...
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NUMERICAL ANALYSIS OF RUBBER BUMPERS INFLUENCE ON THE COLLIDING STEEL STRUCTURES
PublikacjaProblem of collisions of neighbouring structures is one of the important issues related to the safety of civil engineering structures. The safety and reliability of steel structures under impact loading is among a number of different aims during the design state. The aim of this paper is to present the results of numerical investigation of dynamic behavior of closely-separated steel structures under seismic excitation. Modal and transient...
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Import Intensity of Production, Tasks and Wages: Microlevel Evidence for Poland.
PublikacjaObjective: This article relates to recent literature on labour market consequences of production fragmentation within Global Value Chains, analysed in the presence of workers’ heterogeneity and differences in the task content of jobs. The main aim is to assess if there is a relationship between wages of Polish workers and the degree of Polish production dependence on imported inputs. Research Design & Methods: Using microdata from...
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STRUCTURAL CHEMISTRY
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Numerical Modeling of Water and Ice Dynamics for Analysis of Flow Around the Kiezmark Bridge Piers
PublikacjaThis paper presents the results of a numerical model study on the effect of ice on the proposed bridge piers in the Vistula River outlet and its effect on flow conditions in the river. The model DynaRICE is used in this study, which is a two-dimensional hydro-ice dynamic numerical model developed for dynamic ice transport and jamming in rivers. To simulate river hydrodynamics in the vicinity of the bridge piers, 2-dimensional numerical...
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Multidisciplinary approach to the assessment of historic structures based on the case of a masonry bridge in Galicia (Spain)
PublikacjaThe paper presents a general method to evaluate a masonry structure with a complex geometry and unknown material properties. This multidisciplinary approach integrates close range digital photogrammetry,ground probing radar (GPR) and finite elements analysis (FEM) to analyse a masonry bridge. The resulting information from photogrammetry and radar is applied to define a 3D model, which is then used to simulate the behaviour of...
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NONLINEAR ANALYSIS-REAL WORLD APPLICATIONS
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Displacement measurements during load testing of railway arch bridge
PublikacjaThe paper discusses issues concerning load tests carried out on a twin-track, arch railway bridge over the Martwa Wisla river in Gdansk. Currently, it is the bridge with the longest span in its class in Poland. The load-bearing structure consists of three no-hinge arches and an orthotropic deck suspended from them. The studies of the structure assumed the performing of static and dynamic tests. The paper presents the method for...
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Detection and time/frequency analysis of electric fields in the ground
PublikacjaThis paper sets out to detect and characterize electric fields in the ground (such as stray current fields) using a tandem time/frequency method of signal analysis. Results were obtained from investigations performed in the presence of a generated electric field with controlled variable characteristics, and in the presence of an electric field generated by a tramline. The analysis of measurement registers was performed using Short‐Time...
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Geometrically nonlinear analysis of shells
PublikacjaArtykuł porusza zagadnienia nieliniowej analizy powłok wykonanych z materiałów izotropowych. Obliczenia wykonano przy wykorzystaniu dwóch komercyjnych programów wykorzystujących Metodę Elementów Skończonych (Robot Millennium v. 19.0 i MSC.Marc v.2005r2 ). Główną uwagę skupiono na zjawisku zakleszczenia.
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Advanced seismic control strategies for smart base isolation buildings utilizing active tendon and MR dampers
PublikacjaThis paper investigates the seismic behaviour of a five-storey shear building that incorporates a base isolation system. Initially, the study considers passive base isolation and employs a multi-objective archived-based whale optimization algorithm called MAWOA to optimize the parameters of base isolation. Subsequently, a novel model is proposed, which incorporates an interval type-2 Takagi-Sugeno fuzzy logic controller (IT2TSFLC)...
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Comparison of numerical models of impact force for simulation of earthquake-induced structural pounding
PublikacjaW artykule przedstawiono porównanie trzech modeli numerycznych służących do symulacji siły zderzenia w czasie kontaktu pomiędzy konstrukcjami budowlanymi podczas trzęsień ziemi. Efektywność każdego z modeli zbadano porównując wyniki analiz numerycznych z wynikami badań eksperymentalnych. Wyniki pracy pokazują, iż nieliniowy model lepkosprężysty najdokładniej symuluje przebieg czasowy siły zderzenia w czasie kontaktu.
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Theoretical and experimental assessment of parameters for the non-linear viscoelastic model of structural pounding
PublikacjaZjawisko zderzeń pomiędzy sąsiednimi konstrukcjami budowlanymi podczas trzęsień ziemi jest w ostatnim czasie intensywnie badane z wykorzystaniem różnych modeli numerycznych siły zderzenia w czasie kontaktu. Wyniki badań eksperymentalnych pokazują, iż nieliniowy model lepko-sprężysty jest najdokładniejszy wśród modeli stosowanych do analizy. Model ten zdefiniowany jest poprzez dwa parametry: liczbę tłumienia zderzenia oraz parametr...
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Physical models in the education of architectural history
PublikacjaIn this article, the authors present the long tradition and common use of physical models in the process of teaching the history of architecture in higher education institutions. The research described in the article is focused on the use of physical models and mock-ups as stimulants during architectural history classes to support lectures and increase the learning capabilities of students. The authors also cover the general use...
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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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PREDICTION OF SHIP MOTIONS IN IRREGULAR WAVES BASED ON RESPONSE AMPLITUDE OPERATORS EVALUATED EXPERIMENTALLY IN NOISE WAVES
PublikacjaThe most common methods for predicting ship roll motions in a specified sea state are direct measurements of motions in a representative irregular wave realisation (time domain) or calculations of motions from response amplitude operators (RAOs) in the frequency domain. The result of the first method is valid only for the tested sea state, whilst the second method is more flexible but less accurate. RAO-based predictions are calculated...
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Sound intensity distribution around organ pipe
PublikacjaThe aim of the paper was to compare acoustic field around the open and stopped organ pipes. The wooden organ pipe was located in the anechoic chamber and activated with a constant air flow, produced by an external air-compressor. Thus, long-term steady state response was possible to obtain. Multichannel acoustic vector sensor was used to measure the sound intensity distribution of radiated acoustic energy. Measurements have been...
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Use laser to measure girder deflection
PublikacjaThe paper presents a new, simple way to measure deflection of selected intens using the device dkkz-2010, which user a laser light source.
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Increasing the Seismic Resistance of Wood-frame Buildings by Applying PU Foam as Thermal Insulation
PublikacjaWood-frame buildings are very common in regions that are exposed to earthquakes. Most of residential buildings are constructed using this technology; therefore, the seismic resistance of them is really essential in order to prevent human losses and structural damage. The aim of the present article is to show the results of the detailed numerical FEM analysis focused on the seismic behaviour of the wood-frame house with different...
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Comparative Analysis of Developed Rainfall Intensity–Duration–Frequency Curves for Erbil with Other Iraqi Urban Areas
PublikacjaRainfall Intensity–Duration–Frequency (IDF) relationships are widely used in water infrastructure design and construction. IDF curves represent the relationship between rainfall intensity, duration, and frequency, and are obtained by analyzing observed data. These relationships are critical for the safe design of flood protection structures, storm sewers, culverts, bridges, etc. In this study, the IDF curves and empirical IDF formulas...
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Numerical methods for the assessment of bridge safety barriers
PublikacjaThe paper presents a numerical study of the bus crash test for bridge safety barriers. The analysis is conducted with the use of explicit code LS-DYNA. The problem of hourglass effect in shell elements is discussed. The simulations of bus impact against the barrier show that the analyzed barrier withstands the impact forces and restrains the bus trajectory to the bridge road.
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Bridge over Vistula river in Kiezmark. Practical application of nonlinear shell FEM system
PublikacjaPo 40 latach eksploatacji, most drogowy przez rzekę Wisłę w Kiezmarku wymagał wzmocnienia, wynikającego z podniesienia klasy obciążenia do aktualnych wymogów klasy "A". W trakcie prac nad modernizacją konstrukcji, stwierdzono ponad normowe deformacje środników we wszystkich dźwigarach przęseł mostu. Miały one charakter pierwotny i były wynikiem niedbałego wykonania konstrukcji. W referacie przedstawiono wyniki analiz numerycznych...
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A concept of an application to plan the time lines of building selected bridge structures
PublikacjaW rozdziale został przedstawiony przykład autorskiego programu komputerowego przeznaczonego do planowania czasu pracy i kosztów w budownictwie mostowym. Zaletą programu jest możliwość przedstawienia wyników w formie graficznej w sposób deterministyczny i niedeterministyczny. Ma to ogromne znaczenie jeżeli poszukujemy optymalnych rozwiązań dotyczących zagadnień ryzyka i ekonomiki budownictwa.
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Extended Newmark method to assess stability of slope under bidirectional seismic loading
PublikacjaThe paper concerns the dynamic behavior of a simple slope model subjected to simultaneous horizontal and vertical excitations. The proposed method is based on Newmark’s sliding block concept, however, four new features are introduced. The most important assumption is that the normal component of dynamic excitations affects the resisting force both before and after the initiation of the relative slope motion, making it time-dependent....
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Nonlinear Properties of Seawater as a Factor Determining Nonlinear Wave Propagation
PublikacjaTaking practical advantage of nonlinear acoustical interactions occurring in seawater [1, 2] requires knowledge of the parameter of nonlinearity B=A of this medium. The literature does not offer much reports on B=A parameter value for seawater. In the few papers concerning that address the issue, results concerning ocean waters with high salinity and at large depths are given [3], while studies concerning seawater with low salinity...
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Simulation of influence of the air gap asymmetryon voltage waveforms of a synchronous machine
PublikacjaResults of simulation of a synchronous generator with the air gap asymmetry characterised by eccentricity are presented in the paper. The Lagrange's energy method has been used in derivation of the model equations. Analysis of influence of the air gap asymmetry on characteristics of self and mutual inductances of windings, as well as analysis of induced voltage waveforms as a function of the air gap asymmetry have been performed....
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Experimental Study on Effectiveness of a Prototype Seismic Isolation System Made of Polymeric Bearings
PublikacjaSeismic isolation is identified as one of the most popular and effective methods of protecting structures under strong dynamic excitations. Base isolators, such as Lead Rubber Bearings, High Damping Rubber Bearings, and Friction Pendulum Bearings, are widely used in practice in many earthquake-prone regions of the world to mitigate structural vibrations, and therefore minimize loss of life and property damage during seismic events....
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Mathematical Modelling of a Seismic Isolation System to Protect Structures During Damaging Earthquakes
PublikacjaThe present study aims to determine the effectiveness of a nonlinear mathematical model in simulating complex mechanical behaviour of a seismic isolation system to protect structures during strong and damaging earthquakes. In order to construct the Polymeric Bearings considered in this research, a specially prepared flexible polyurethane elastomer with increased damping properties has been used. The usefulness of the proposed mathematical...
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A dynamic vehicle-bridge model based on the modal identification results of an existing EN57 train and bridge spans with non-ballasted tracks
PublikacjaThis paper addresses the methodology of the bridge-vehicle dynamic model definition based on the free response measurements of an existing train and existing bridge spans. In the case of the railway vehicle, the methodology uses the impulse excitations of a single car by means of the wedge method. In the case of the bridge spans, free responses are collected after the passages of trains. The global modal parameters (frequencies...
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Journal of Nonlinear Functional Analysis
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Nonlinear Analysis-Hybrid Systems
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Nonlinear Functional Analysis and Applications
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Communications on Applied Nonlinear Analysis
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Nonlinear Analysis-Modelling and Control
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Journal of Nonlinear Modeling and Analysis
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Journal of Nonlinear and Convex Analysis
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Journal of Nonlinear and Variational Analysis
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EXPERIMENTAL AND NUMERICAL STUDY ON COLLISIONS BETWEEN STEEL STRUCTURES UNDER EARTHQUAKE EXCITATION
PublikacjaIn 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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Simulation of parallel similarity measure computations for large data sets
PublikacjaThe 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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Study of displacements of a bridge abutment using FEM
PublikacjaSteel sheet piles are often used to support excavations for bridge foundations. When they are left in place in the permanent works, they have the potential to increase foundation bearing capacity and reduce displacements; but their presence is not usually taken into account in foundation design. In this article, the results of finite element analysis of a typical abutment foundation, with and without cover of sheet piles, are presented...
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Hybrid technique for the analysis of scattering from periodic structures composed of irregular objects
PublikacjaW pracy zaproponowano nową metodę hybrydową do badania zjawiska rozpraszania fali elektromagnetycznej na strukturach periodycznych złożonych z obiektów rozpraszających o nieregularnym kształcie. Zaprezentowana metoda została wykorzystana do badania własności nowych struktur falowych. Uzyskane wyniki numeryczne zostały zweryfikowane eksperymentalnie.
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Digital Photogrammetry in the Analysis of the Ventricles' Shape and Size
PublikacjaThis article presents spatial analyzes conducted to assess the potential of ReMake software to be used for medical purposes, with emphasis on the analysis of the shape and dimensions of the ventricles. To achieve this goal, the length of the sections measured with the ReMake and Image Master programs have been compared. RMS error was on the level of 1.2 mm. In addition to indicating the appropriateness of using this software, there...
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EFEKTYWNOŚĆ STOSOWANIA ZDERZAKÓW STYROPIANOWYCH POMIĘDZY ZDERZAJĄCYMI SIĘ KONSTRUKCJAMI STALOWYMI
PublikacjaPodczas wstrząsów sejsmicznych o różnym natężeniu, wielokrotnie obserwowano zjawisko zde-rzania się konstrukcji ze sobą sąsiadujących, co mogło prowadzić nawet do jej całkowitego zniszczenia. Na podstawie obserwacji, badań numeryczny i eksperymentalnych stwierdzono, że przyczyną kolizji jest niedostateczna przerwa pomiędzy konstrukcjami. Ponadto czynnikami, które również mogą doprowadzić do zderzeń są różnice w masach lub sztywnościach...
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Elastoplastic nonlinear FEM analysis of FGM shells of Cosserat type
PublikacjaThe paper is a continuation of [1] where the formulation of the elastic constitutive law for functionally graded materials (FGM) on the grounds of nonlinear 6-parameter shell theory with the 6th parameter (the drilling degree of freedom) was presented. Here the formulation is extended to the elasto-plastic range. The material law is based on Cosserat plasticity and employs the well-known Tamura-Tomota-Ozawa (TTO) [2] mixture...
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Time reversal invariant single-gap superconductivity with upper critical field larger than the Pauli limit in NbIr2B2
PublikacjaRecently, compounds with noncentrosymmetric crystal structure have attracted much attention for providing a rich playground in search for unconventional superconductivity. NbIr2B2 is a new member to this class of materials harboring superconductivity below Tc = 7.3(2) K and a very high upper critical field that exceeds Pauli limit. Here we report on muon spin rotation (μSR) experiments probing the temperature and field dependence...
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An Objective Focussing Measure for Acoustically Obtained Image
PublikacjaIn scientific literature many parameters of an image sharpness can be defined, that can be used for the evaluation of display energy concentration (EC). This paper proposes a new, simple approach to EC quantitative evaluation in spectrograms, which are used for the analysis and visualization of sonar signals. The presented approach of the global-image EC measure was developed to the evaluation of EC in arbitrary direction (or at...
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The content of high-intensity sweeteners in different categories of foods available on the Polish market
PublikacjaThe objective of this study was to measure the concentrations of nine high-intensity sweeteners (acesulfame-K, aspartame, alitame, cyclamate, dulcin, neohesperidin DC, neotame, saccharin and sucralose) in different categories of food available on the Polish market. Over 170 samples of different brands of beverages, yoghurts, fruit preparations, vegetable preserves and fish products were analysed using an analytical procedure based...
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Reference FEM model for SHM system of cable-stayed bridge in Rzeszów
PublikacjaThe paper presents the references model for structural health monitoring system (SHM) of cable-stayed bridge recently constructed in Rzeszów over Wisłok River. The SHM system is design to provide on-line information on the structure state and facilitate its maintenance procedures. The main feature of the SHM system is permanent observation of the dynamic behavior of the bridge with focus on cable vibrations. The paper discusses...
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Numerical study on seismic response of a base-isolated building modelled with shell elements
PublikacjaSeismic isolation is counted among the most popular and effective means of protecting structures against earthquake forces. Base isolators, like Lead-Rubber Bearings (LRB), High-Damping Rubber Bearings (HDB) or Friction Pendulum Systems (FPS) are extensively used in practice in many earthquake-prone regions of the world. The present paper reports the results obtained from the numerical study on seismic response of a base-isolated...