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Wyniki wyszukiwania dla: numerical modelling of backs-cattering by fish
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Numerical modelling of 3D printout using line (1D) elements
PublikacjaA proposition of some numerical modelling of the 3D printout is presented in the paper. The proposed model is composed of some 1D elements. The resulting numerical model of the infill consist of beam, spring and rigid elements. Obtained results confirm correctness of the proposed modelling method. Two methods of estimation of the spring parameters are proposed in the paper. In the first method, mechanical properties of the connecting...
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Numerical Modelling of Forced Convection of Nanofluids in Smooth, Round Tubes: A Review
PublikacjaA comprehensive review of published works dealing with numerical modelling of forced convection heat transfer and hydrodynamics of nanofluids is presented. Due to the extensive literature, the review is limited to straight, smooth, circular tubes, as this is the basic geometry in shell-and-tube exchangers. Works on numerical modelling of forced convection in tubes are presented chronologically in the first part of the article....
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A novel heterogeneous model of concrete for numerical modelling of ground penetrating radar
PublikacjaThe ground penetrating radar (GPR) method has increasingly been applied in the non-destructive testing of reinforced concrete structures. The most common approach to the modelling of radar waves is to consider concrete as a homogeneous material. This paper proposes a novel, heterogeneous, numerical model of concrete for exhaustive interpretation of GPR data. An algorithm for determining the substitute values of the material constants...
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The Influence of Selected Parameters of Numerical Modelling on Strains and Stresses at Weld Toe Notch
PublikacjaLatest 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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FEM-based wave propagation modelling for SHM: Certain numerical issues in 1D structures
PublikacjaThe numerical modelling of structural elements is an important aspect of modern diagnostic systems. However, the process of numerical implementation requires advanced levels of consideration of multiple aspects. Important issues of that process are the positive and negative aspects of solution applied methods. Therefore the aim of this article is to familiarise the reader with the most important aspects related to the process of...
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Numerical modelling of the mesofracture process of sintered 316L steel under tension using microtomography
PublikacjaThis paper concerns numerical modelling of the deformation process, taking into account the local fracture of porous 316L sinters at the mesoscopic scale using the finite element method. Calculations are performed with the use of geometrical models, to map the realistic shape of the porous mesostructure of the material, obtained by means of computed microtomography. The microtomographic device has limited and insufficient measurement...
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Numerical Modelling of Connections Between Stones in Foundations of Historical Buildings
PublikacjaThe aim of this paper is to analyse the behaviour of old building foundations composed of stones (the main load-bearing elements) and mortar, based on numerical analysis. Some basic aspects of historical foundations are briefly discussed, with an emphasis on their development, techniques, and material. The behaviour of a foundation subjected to the loads transmitted from the upper parts of the structure is described...
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Numerical Modelling of Structures with Uncertainties
PublikacjaThe nature of environmental interactions, as well as large dimensions and complex structure of marine offshore objects, make designing, building and operation of these objects a great challenge. This is the reason why a vast majority of investment cases of this type include structural analysis, performed using scaled laboratory models and complemented by extended computer simulations. The present paper focuses on FEM modelling...
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Modelling and Measurement of Folk Guitar: Truss Rod and Strings in Numerical Analysis of Tone
PublikacjaThe study makes an attempt to model a complete vibrating guitar including its non-linear features, specifically the tension-compression of truss rod and tension of strings. The purpose of such a model is to examine the influence of design parameters on tone. Most experimental studies are flawed by uncertainties introduced by materials and assembly of an instrument. Since numerical modelling of instruments allows for deterministic...
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Numerical modelling and analysis of steel specimens subjected to marine immersed corrosion and tensile load
PublikacjaThe present study develops numerical models to analyse the behaviour of steel specimens subjected to marine immersed corrosion degradation and tensile load. The finite element method with the use of the explicit dynamic solver LS-DYNA, satisfying the quasi-static conditions, is employed. Two numerical models are developed, where in the first one, the scans of surfaces gathered from corroded plate specimens are implemented directly...
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Numerical Modelling of Shear Localization in Granular Bodies using MPM and Non-local Hypoplasticity
PublikacjaThe paper deals with modelling of shear localization in granular bodies by means of an enhanced hypoplastic constitutive model and material point method (MPM). The calculations were carried out for plane strain compression of non-cohesive sand. In order to properly capture the width and inclination of shear zones, the constitutive model was enriched by a characteristic length of micro-structure by means of a non-local theory....
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Numerical modelling of DMT test in calibration chamber
PublikacjaAnaliza numeryczna badania DMT wykonanego w komorze kalibracyjnej w Katedrze Geotechniki Politechniki Gdańskiej. Badania przeprowadzono w piasku Lubiatowo średnio zagęszczonym i zagęszczonym przy składowej pionowej naprężenia 100 kPa. Modelowano proces wciskania ostrza dylatometru oraz fazę odkształcenia membrany. Analiza parametryczna uwzględnia wpływ wartości kąta tarcia wewnętrznego i dylatancji oraz modułu odkształcenia uzyskanych...
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Numerical FDM modelling of wave propagation in concrete structure
PublikacjaThe article presents application of finite difference method to damage detection and its size evaluation in concrete structure by elastic wave propagation method. The simulations of wave propagation in concrete structure were performed for six different damage scenarios. Damages were modelled as areas with changed material properties. Investigation focused on the influence of damage size on the energy of wave reflection. Presented...
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Numerical modelling of thermodynamics and dynamics of sea ice in the Baltic Sea
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Numerical modelling of conical wave formation in multimode optical fibers
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Numerical modelling and experimental verification of compressible squeeze film pressure
PublikacjaThe validity of using the Reynolds equation for compressible squeeze film pressure was tested with computational fluid dynamics (CFD). A squeeze film air bearing was instrumented with pressure sensors and non-contacting displacement probes to provide transient measurements of film thickness and pressure. The film thickness measurements also provided input parameters to the numerical prediction. However, numerical results showed...
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Numerical modelling of elasto-viscoplastic Bodner-Partom constitutive equations
PublikacjaArtykuł omawia wykorzystanie specjalnej procedury UVSCPL umożliwiającej wprowadzenie do komercyjnego programu MSC.Marc sprężysto-lepkoplastycznych równań modelu Bodnera-Partoma. Prezentuje szereg przykładów statycznych i dynamicznych, które potwierdzają poprawność zaproponowanej koncepcji analizy konstrukcji z wykorzystaniem rozpatrywanego prawa Bodnera-Partoma.
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NUMERICAL MODELLING AND EXPERIMENTATION OF HISTORICAL CARPENTRY CORNER LOG JOINTS
PublikacjaThe main purpose of this research is to determine the stress distributions on the contact surfaces between the logs of the historical carpentry corner joints. The additional purpose is to compare the stress distribution for four different boundary conditions in the case of dry and wet pine wood. The paper presents the results of numerical analysis of the shortcorner dovetail connection and the saddle notch corner joint, which are...
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The effect of numerical 2D and 3D FEM element modelling on strain and stress distributions at laser weld notches in steel sandwich type panels
PublikacjaLike other means of transport, merchant ships face the problem of increasing requirements concerning the environment protection, which, among other issues, implies the reduction of fuel consumption by the ship. Here, the conventional approach which consists in making use of higher strength steels to decrease the mass of the ship hull can be complemented by the use of new steel structures of sandwich panel type. However, the lack...
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Numerical modelling of water transport processes in partially-connected tidal basins
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Numerical modelling of elasto-viscoplastic Chaboche constitutive equations using MSC.Marc.
PublikacjaArtykuł omawia wykorzystanie specjalnej procedury UVSCPL umożliwiającej wprowadzenie do komercyjnego programu MSC.Marc sprężysto-lepkoplastycznych równań modelu Chaboche'a. Prezentuje szereg przykładów numerycznych, które potwierdzają poprawność zaproponowanej koncepcji analizy konstrukcji z wykorzystaniem rozpatrywanego prawa Chaboche'a ze zniszczeniem.
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The statistical impact of experimental result scatter of asphalt mixtures on their numerical modelling
PublikacjaThe paper presents selected test results of asphalt mixture conducted in low temperatures. The obtained parameters are highly diverse. It concerns ultimate breaking loads, stiffness parameters related to Young's modulus but also the fracture course. Statistical analysis upon the results makes it possible to relevantly estimate the material-defining parameter values. Such a random approach leads to the mean values of breaking and...
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Numerical modelling of moored floating structures using SPH. Preliminary results
PublikacjaThis article presents partial results of the works carried out under the research project "The development of the methodof modeling the dynamics of the floating (offshore) objects subjected to the environment influence", which aims at developing computational methods for modeling the dynamics of offshore structures.The article contains the description of the method of modeling the hydrodynamic impacts using SPH method and the description...
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Modelling of wave propagation in spatial frame elements - numerical simulations and experimental works
PublikacjaW pracy porównano rozwiązania propagacji fal sprężystych w ośrodku typu belka Timoszenki, uzyskane na drodze eksperymentalnej i numerycznej. Do obliczeń numerycznych wykorzystano wielowęzłowe spektralne elementy skończone klasy C0.Omówiono algorytm całkowania po czasie i sformułowano wnioski dotyczące liczby węzłów na długość fali.
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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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Numerical modelling of asymetric double-layer Al-Cu plate rolling process
PublikacjaNiekorzystnym 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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Advanced numerical modelling for predicting residual compressive strength of corroded stiffened plates
PublikacjaAn 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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Constitutive Modelling of Knitted Abdominal Implants in Numerical Simulations of Repaired Hernia Mechanics
PublikacjaThe 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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Turbulence model evaluation for numerical modelling of turbulent flow and heat transfer of nanofluids
PublikacjaIn 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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Certain numerical issues of wave propagation modelling in rods by the Spectral Finite Element Method
PublikacjaW pracy omówiony zagadnienia związane z modelowaniem propagacji fal sprężystych metodą Spektralnych Elementów Skończonych. Przedstawiono wpływ postaci macierzy mas na błędy rozwiązania. Omówiono zakres stosowalności modeli.
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Physical and numerical modelling of heat-flow processes in tangentially pulverized fuel-fired boiler
PublikacjaPraca przedstawia wykorzystanie eksperymentalnego modelowania fizycznego kwasowo-zasadowego do modernizacji kotła pyłowego z tangencjalną komorą spalania w aspekcie ograniczenia emisji toksycznych składników węgla, siarki i azotu oraz doboru optymalnych parametrów termodynamicznych mieszania i spalania. Dodatkowo, w celu porównania wyników pomiarów kotła po modernizacji, wykonano obliczenia numeryczne z zastosowaniem oprogramowania...
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Physical and numerical modelling of flow pattern and combustion process in pulverized fuel fired boiler.
PublikacjaW pracy przedstawiono źródła powstawania toksycznych związków podczas procesu spalania, metody ich redukcji. Do tego zadania wykorzystano eksperymentalne modelowanie fizyczne i uzupełniono je modelowaniem numerycznym. Obie metody, techniki modelowania miały na celu optymalizację procesu spalania.Wyniki obliczeń numerycznych porównano z pomiarami.
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Numerical modelling of different airbag folding patterns and their influence on occupant responses in frontal vehicle impact
PublikacjaThis paper presented a procedure for airbag folding for the application in occupant safety studies and analysed the influence of different airbag folding patterns on the occupant severity in frontal impact. Airbags were folded in two patterns: zig-zag and top-roll, using two folding techniques: Initial Metric Method and Explicit Folding. The explicit folding was found to be more expensive in terms of preparation time. However,...
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Numerical Modelling for Prediction of Compression Index from Soil Index Properties in Jimma town, Ethiopia
PublikacjaIn this study, correlations are developed to predict compression index (Cc) from index parameters so that one can be able to model Jimma soils with compression index using simple laboratory tests. Undisturbed and disturbed soil samples from twelve different locations in Jimma town were collected. Laboratory tests like specific gravity, grain size analysis, Atterberg limit, and one-dimensional consolidation test for a total of twenty-four...
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Combining Satellite Imagery and Numerical Modelling to Study the Occurrence of Warm Upwellings in the Southern Baltic Sea in Winter
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Interaction Between Storm Water Conduit Flow and Overland Flow for Numerical Modelling of Urban Area Inundation
PublikacjaNowadays we can observe increasing frequency of inundations in cities. This makes accurate predicting of inundations more important than ever. Numerical modeling of this issue requires complex approach with simultaneous calculations of pipe flow and surface flow. In this paper, after a short review of known methods used for solving pipe and surface flow, we will try to answer the question if presented methods would be sufficiently...
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Methodology of the Morphometry Study on Baltic Herring
PublikacjaAcoustic techniques are used in the estimation of the abundance of Baltic herring. Investigations of the relationship between the Baltic herring individual target strength TS and the total fish length L, significant in the acoustic assessment, demonstrated its de-pendence on the study area location. It motivated the detailed analysis of the relationship between herring from the southern Baltic ICES Subdivisions 24, 25, and 26,...
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New Concept of Numerical Ship Motion Modelling for Total Ship Operability Analysis by Integrating Ship and Environment Under One Overall System
PublikacjaThe paper presents a new concept of overall ship motion modelling for application to total ship operability. The delivered model is a multi-phase and includes both submerged part of ship’s hull and the surrounding water as a unique body. The Discrete Finite Element Method is applied. The model is successfully examined and illustrated for a selected AHTS.
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Numeryczne modelowanie prędkości płynięcia warstw blachy bimetalowej w procesie walcowania = The numerical modelling of the layers flow velocity in bimetal plates rolling proces
PublikacjaW pracy przedstawiono wyniki obliczeń numerycznych dotyczących procesu asymetrycznego walcowania blach bimetalowych 18G2A+1H13.
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Backscattering properties of southern Baltic herring
PublikacjaReliable TS(L) relationship is required to improve acoustic algorithms of abundanceestimation of Baltic herring. The relationships, empirically obtained in different parts of theBaltic Sea, produce up to 8 dB – difference in the herring TS. In order to develop an accurateTS(L) relationship, it is important to analyze factors controlling the TS variability. Thepossible impact of the regional difference...
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Numerical modelling of POC dynamics in the southern Baltic under possible future conditions determined by nutrients, light and temperature**The study was financially supported by the Polish Ministry of Science and Higher Education (grants: NN305 111636 and NN306 404338) and Baltic-C – the BONUS funded project.
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On the acoustic backscattering by Baltic herring and sprat
PublikacjaAccurate abundance estimate of Baltic clupeids, herring and sprat, is required for theirsustainable exploitation. The understanding the sound backscattering of individual fish isimportant for employing the acoustical techniques, which are widely used in the estimation.The previous studies demonstrated that the improvement of the understanding is critical forthe Baltic herring and sprat. It was the main...
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Modelling of acoustic backscattering by southern Baltic herring
PublikacjaAssessment of Baltic herring abundance can be carried out using acoustic techniques. Analysis of the relationship between the Baltic herring individual target strength, TS, and the total fish length, L, important for the acoustic assessment, showed the relationship to be dependent on the location of the study area. This finding motivated a detailed analysis of the relationship for the herring occurring in the southern Baltic...
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Numerical evaluation of dynamic response of an experimentally tested base-isolated and fixed-base steel structure model
PublikacjaSeismic isolation is recognized as one of the most popular and effective methods of protecting structures during earthquake. The present paper is focused on the comparison be-tween the dynamic responses of buildings with fixed and isolated bases exposed to seismic exci-tations. The aim of the study is to investigate the effectiveness of a simplified base isolation numerical modelling technique using the linear springs. One-storey...
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On the influence of the acceleration recording time on the calculation of impact severity indexes
PublikacjaThe paper concerns with the analysis of normative requirements pertaining to experimental setup of a crash test and its numerical modelling. An overview of parameters describing the collision of a vehicle with a road restraining system is presented. A short description of a concrete road safety barrier is presented. A brief description of numerical modelling procedures for crash tests is given as well. The parametric influence...
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Thermal-FSI modeling of flow and heat transfer in a heat exchangerbased on minichanels
PublikacjaIn this paper selected numerical modelling problems for an advanced thermal-FSI ("Fluid Solid Interaction") mini-channel heat exchanger model are presented. Special attention is given to the heat transfer between the separated mediums for different mass flows. Similar modelling problems have also been discussed in the literature dedicated to numerical and theoretical modelling problems for typical heat exchangers [1, 2, 3]. Basic...
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Dynamic analysis of lightweight structure of the Viaduct Millau in France subjected to the wind fluctuations described by Karman’s and Davenport’s spectrum
PublikacjaThe article presents numerical simulations for wind impact modelling on the Millau Viaduct structure in France performed with two independent spectrum generation methods. The viaduct's construction in affected by strong forces, as it is situated in the Tarn river's valley. Thus, the loading coming from the wind cannot be modelled, the way it is in case of simple structures as static loading, but as a loading in a form of a spectrum...
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Rigid finite elements and multibody modelling used in estimation and reduction of rod vibrations
PublikacjaIn the paper, a mechanical set composed of a robot (manipulator) and of an elastic beam is considered. The beam is fixed to the top of the robot structure. In most of the similar cases, undesired vibrations can be excited in the beam. They are especially significant, when dynamics in the robot braking period is examined. In the paper, estimation and modification of length of the braking period is proposed, in order to reduce the...
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Modal analysis of a fish-belly flap type of steel water gate
PublikacjaABSTRACT: The results of a modal analysis of the fish-belly flap type of steel water gate are presented in the paper. The analysis was conducted for a detailed numerical model of the structure using four-node quadrilateral shell elements. The study was focused on the examination of the influence of positioning of the flap gate and hydrostatic pressure of water on the eigenvalues and eigenmodes of the structure. The results of the study...
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Cyclic behaviour modelling of additively manufactured Ti-6Al-4V lattice structures
PublikacjaThe present work is concerned with the numerical modelling of the cyclic behaviour of Ti-6Al-4V lattice structures. In the study, diamond structures of titanium alloy produced by the additive laser powder bed fusion (LPBF) method with different degrees of relative density were used. Realistic geometric models of the studied mesostructures were generated using computed microtomography, taking into account the imperfections of the...