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Repozytorium publikacji
Politechniki Gdańskiej

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Publikacje z roku 2014

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  • Nowoczesne metody usuwania śniegu i lodu z powierzchni użytkowych
    • Rafał Andrzejczyk
    • Tomasz Muszyński
    • Przemysław Kozak
    2014 Materiały Budowlane

    W artykule zostały przedstawione klasyczne metody usuwania śniegu i lodu z nawierzchni użytkowych. Dokonano analizy skutków wykorzystywania środków chemicznych. Opisano szacunkowe koszty wynikające z konieczności utrzymania nawierzchni użytkowych „niszczonych” w skutek zmian temperaturowych i wykorzystywanych środków chemicznych. Przedstawiono nowoczesne metody odmrażania oparte o zastosowanie systemów podgrzewania elektrycznego jak i układów wykorzystujących odnawialne źródła energii. W artykule położono nacisk na rozszerzenie informacji w zakresie stosowalności i technologii pasywnych układów odladzania opartych o wykorzystywanie rurek ciepła i układów termosyfonowych. Zaprezentowano budowę stanowiska pomiarowego i zaawansowanie prac badawczych w kierunku opracowania wysokoefektywnego układu odladzania/odśnieżania powierzchni wykorzystującego rurkę ciepła (termosyfon).

  • Nowoczesne układy przekształtników wielopoziomowych do zasilania statków z lądu
    • Krzysztof Blecharz
    • Zbigniew Krzemiński
    2014 Automatyka Elektryka Zakłócenia

    W artykule poruszono tematykę zasilania statków zacumowanych w porcie z lądowej sieci elektroenergetycznej poprzez wykorzystanie nowoczesnych konstrukcji przekształtników energoelektronicznych. W treści pracy zaprezentowano porównanie dwóch topologii wysokonapięciowych przekształtników wielopoziomowych. Porównano konstrukcje przekształtników z klasycznym transformatorem wielouzwojeniowym oraz z transformatorami wysokoczęstotliwościowymi.

  • Nowy algorytm wyznaczania położenia obiektów na podstawie pomiarów odległości w środowisku wewnątrzbudynkowym
    • Agnieszka Czapiewska
    2014 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    W referacie został przedstawiony nowy algorytm wyznaczania położenia obiektów na podstawie pomiarów odległości, który jest przeznaczony dla środowisk wewnątrzbudynkowych. Następnie porównano zaproponowany algorytm z powszechnie stosowanym algorytmem Foya na rzeczywistych pomiarach odległości obarczonych błędami wynikającymi z propagacji wielodrogowej.

  • Nowy polski katalog typowych konstrukcji nawierzchni podatnych i półsztywnych
    • Józef Judycki
    • Piotr Jaskuła
    • Marek Pszczoła
    • Dawid Ryś
    • Mariusz Jaczewski
    • Jacek Alenowicz
    • Bohdan Dołżycki
    • Marcin Stienss
    2014 Pełny tekst Inżynieria Morska i Geotechnika

    Przyczyny opracowania i nowowprowadzone elementy katalogu. Uporządkowanie terminologii. Obliczenia ruchu projektowego i nowe współczynniki przeliczeniowe. Nowe materiały i technologie oraz klasyfikacja warunków gruntowo-wodnych. Projektowanie warstw wzmacniających podłoże gruntowe i górnych warstw nawierzchni.

  • Nowy wzorzec willi modernistycznej lat trzydziestych w Gdyni - willa z półokrągłą werandą. Powojenna kontynuacja idei
    • Maria Sołtysik
    2014

    Na początku lat trzydziestych pokawił się w architekturze Gdyni nowy typ willi - willa z półokrągłą, parterową werandą Stanowiła ona wyrazisty element plastyczny kompozycji przestrzennej i zyskała dużą popularność w realizacjach do końca 1939 r. Motyw ten był także stosowany często w architekturze powojennejo,, a zaczął zanikać dopiero w latach 60. XX wieku.

  • Numerical analysis of a temporary steel grandstand
    • Natalia Lasowicz
    • Robert Jankowski
    2014

    The purpose of this paper is to present the results of the numerical analysis focused on the response of the temporary steel scaffolding grandstand subjected to human-induced vibrations due to jumping. Shell as well as beam elements have been used in the numerical model. Its first stage has involved conducting modal analysis in order to determine the modes of free vibrations and the corresponding natural frequencies for the empty and occupied grandstand. Then, the horizontal displacement and acceleration time histories have been obtained as the result of dynamic analysis. A human-vibration perception has been considered. The results of the study confirm that there is a substantial level of interaction between the mass of spectators and the grandstand. Crowd load provides additional mass that has a significant influence on the structure leading to the reduction of natural frequencies and influencing the level of human-vibration perception and comfort.

  • Numerical analysis of elastic wave propagation in unbounded structures
    • Arkadiusz Żak
    • Marek Krawczuk
    • Łukasz Skarbek
    • Magdalena Palacz
    2014 Pełny tekst FINITE ELEMENTS IN ANALYSIS AND DESIGN

    The main objective of this paper is to show the effectiveness and usefulness of the concept of an absorbing layer with increasing damping (ALID) in numerical investigations of elastic wave propagation in unbounded engineering structures. This has been achieved by the authors by a careful investigation of three different types of structures characterised by gradually increasing geometrical and mathematical description complexities. The analysis includes propagation of longitudinal elastic waves in a 1-D semi-infinite isotropic rod, modelled according to the classical 1-mode theory of rods, propagation of coupled shear and flexural elastic waves in a 1-D semi-infinite isotropic beam modelled according to the Timoshenko beam theory, as well as propagation of elastic waves in a 3-D semi-infinite isotropic half-pipe shell modelled by a 6-mode theory of shells. The concept of the ALID has been not only presented by the authors, but certain relations between the ALID properties and the characteristics of propagating elastic waves have been given that can help to maximise the ALID performance in terms of its damping capability. All results of numerical calculations presented by the authors in this work have been obtained by the use of the Time-domain Spectral Finite Element Method (TD-SFEM).

  • NUMERICAL ANALYSIS OF RUBBER BUMPERS INFLUENCE ON THE COLLIDING STEEL STRUCTURES
    • Barbara Sołtysik
    2014 Dokonania Młodych Naukowców

    Problem 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 dynamic analyses, using the Finite Element Method (MES) for three models in series, have been conducted in software MSC Marc 2008. The influence of collisions on structural behavior was investigated. In addition, the influence of rubber bumpers located between structures was taken under consideration. The results of the study indicate that collisions may significantly influence the structural behavior, leading to the increase and decrease of the response and that depends on the gap size.

  • Numerical Analysis of the Unsteady Propeller Performance in the Ship Wake Modified by Different Wake Improvement Devices
    • Jan Szantyr
    • Tomasz Bugalski
    2014 Pełny tekst Polish Maritime Research

    The paper presents summary of numerical analysis of the unsteady propeller forces and induced pressure pulses generated by the selected real propeller of 7000 tons product tanker, operating in five different wakefields including four inflenced by the different wake improvement devices. The results of the analysis are partly compared with experimental data and univocal conclusions about the optimum wake improvement device are presented.

  • Numerical and experimental investigation of rotational stiffness of zed-purlins connection with sandwich panels
    • Marcin Kujawa
    • Czesław Szymczak
    2014 THIN-WALLED STRUCTURES

    A rotational resistant stiffness of the zed-purlins connection with sandwich panels is investigated. A simple finite element method model of the connection is proposed. The numerical analysis of the model performed by ABAQUS software, in physically linear and geometrically nonlinear ranges, leads to the rotational resistant stiffness sought. The numerical solution obtained is verified experimentally. Two variants of distribution of screws connecting the purlin with the sandwich panel are taken into investigation. A good agreement of both, theoretical and experimental, results should be noticed. Conclusion related to possible application in design practice is formulated.

  • Numerical Comparison of Damping Amplification Effects Obtained in Neighborhood of a Mechanism Singular Position - Viscous and Electromagnetic Cases
    • Krzysztof Lipiński
    2014 Key Engineering Materials

    In the paper, results of numerical investigations are presented. A continuous beam is considered as the main vibrating element. Two energy dissipations methods are compared: viscous dampers and DC generators. To increase the damping effectiveness, velocity amplification is proposed, i.e., a mechanism is introduced between the beam and the damping element, and the mechanism configuration is set as closed to the singular position of it. According to some observed fundamental differences in the guiding physical properties of blocks present in the considered system, two structurally different sub-models are introduced in the numerical model of the complete system. The first sub-model corresponds to the amplification mechanism (considered as composed of rigid elements). The mechanism is modelled as a multibody system. The second sub-model corresponds to the continuous beam. The beam is modelled with used of the finite elements technique. To joint the sub-models, constraint equations are proposed. They express a revolute joint that is present between the mechanisms second rod and the beam enforced to vibrate.

  • Numerical investigations of effect of indoor air quality on thermal comfort in residential buildings.
    • Marek Krzaczek
    • Andrzej Tejchman-Konarzewski
    2014 Pełny tekst Archives of Civil Engineering

    Artykuł przedstawia wyniki numeryczne MES odnośnie wpływu koncentracji CO2 w lokalnej strefie powietrza w budynkach mieszkalnych naturalnie wentylowanych na zachowanie mieszkańców. Obliczenia wykonano w 2 wymiarach. Zbadano wpływ położenia mieszkańców i prędkości wchodzącego powietrza.

  • NUMERICAL SIMULATION OF CRATER CREATING PROCESS IN DYNAMIC REPLACEMENT METHOD BY SMOOTH PARTICLE HYDRODYNAMICS
    • Andrzej Danilewicz
    • Zbigniew Sikora
    2014 Pełny tekst Studia Geotechnica et Mechanica

    A theoretical base of SPH method, including the governing equations, discussion of importance of the smoothing function length, contact formulation, boundary treatment and finally utilization in hydrocode simulations are presented. An application of SPH to a real case of large penetrations (crater creating) into the soil caused by falling mass in Dynamic Replacement Method is discussed. An influence of particles spacing on method accuracy is presented. Anexample calculated by LS-DYNA software is discussed. Chronological development of Smooth Particle Hydrodynamics is presented. Theoretical basics of SPH method stability and consistency in SPH formulation, artificial viscosity and boundary treatment are discussed. Time integration techniques with stability conditions, SPH+FEM coupling, constitutive equation and equation of state (EOS) are presented as well.

  • Numerical simulation of laminate composite specimens failure
    • Bartosz Sobczyk
    2014

    This work presents some numerical results concerning simulation of failure of laminate composite specimens. In the article two tests to determine ultimate strength in an orthotropic layer, are considered: tension (TT1) and compression (TC1) test. The outcome is compared with experimental data provided by [9,10].

  • Numerical simulation of screw displacement pile interaction with non-cohesive soil
    • Adam Krasiński
    2014 Pełny tekst Archives of Civil and Mechanical Engineering

    A trial numerical simulation of screw displacement pile interaction with non-cohesive subsoil during the transfer of compression load. The simulation was carried out in an axisymmetric system. The technological phases of pile installation in the ground were numerically modelled using equivalent processes which provided similar effects to real technical actions. The results of the numerical calculations were verified by comparing them with the load test results of a real pile in the field.

  • Numerical Simulations and Tracer Studies as a Tool to Support Water Circulation Modeling in Breeding Reservoirs
    • Piotr Zima
    2014 Pełny tekst Archives of Hydro-Engineering and Environmental Mechanics

    The article presents a proposal of a method for computer-aided design and analysis of breeding reservoirs in zoos and aquariums. The method applied involves the use of computer simulations of water circulation in breeding pools. A mathematical model of a pool was developed, and a tracer study was carried out. A simplified model of two-dimensional flow in the form of a biharmonic equation for the stream function (converted into components of the velocity vector) was adopted to describe the flow field. This equation, supplemented by appropriate boundary conditions, was solved numerically by the finite difference method. Next, a tracer migration equation was solved, which was a two-dimensional advection-dispersion equation describing the unsteady transport of a non-active, permanent solute. In order to obtain a proper solution, a tracer study (with rhodamine WT as a tracer) was conducted in situ. The results of these measurements were compared with numerical solutions obtained. The results of numerical simulations made it possible to reconstruct water circulation in the breading pool and to identify still water zones, where water circulation was impeded.

  • Numerical simulations of novel GFRP sandwich footbridge
    • Jacek Chróścielewski
    • Wojciech Witkowski
    • Bartosz Sobczyk
    • Karol Daszkiewicz
    2014

    In the following paper some aspects of numerical analysis and designing stages of a footbridge made of composite materials are elucidated. Because of the used materials the design process in this case is not ordinary and requires the development of concepts, material selections, identification of material properties, numerical simulations, strength calculations, serviceability and durability analyses. This contribution presents some aspects of the design process. The primary attention is focused on the method of estimating load capacity of a composite sandwich structure. Additionally, a selection of dimensions of the footbridge according to the regulations of the Polish Ministry of Infrastructure is presented. The main concepts of designing of the final form of the structure are discussed. Finally, the report compares two different finite element method models prepared to describe global behaviour of the structure. The models are based on shell and shell and solid finite elements.

  • Numerical Simulations of Seepage in Dikes Using unsaturated and Two-Phase Flow Models
    • Witold Tisler
    • Adam Szymkiewicz
    2014

    Modeling of water flow in variably saturated porous media, including flood dikes, is often based on the Richards equation, which neglects the flow of pore air, assuming that it remains at constant atmospheric pressure. However, there is also evidence that the air flow can be important, especially when the connectivity between the pore air and atmospheric air is lost. In such cases a full two-phase air-water flow model should be used. This paper presents numerical simulations of seeepage in dikes based on these two mathematical models. The models were implemented in a general purpose commercial finite element solver FlexPDE. Two boundary problems were considered, corresponding to seepage through dike and overtopping of the dike. In the case of seepage through the dike the two-phase model predicted significantly slower development of the outflow at the inner (landward) slope of the dike as compared to the Richards equation. In the second scenario (overtopping) we observed slower infiltration in the central, unsaturated part of the dike according to the two-phase model.

  • Numerical solution of fractional neutron point kinetics in nuclear reactor
    • Tomasz Nowak
    • Kazimierz Duzinkiewicz
    • Robert Piotrowski
    2014 Pełny tekst Archives of Control Sciences

    This paper presents results concerning solutions of the fractional neutron point kinetics model for a nuclear reactor. Proposed model consists of a bilinear system of fractional and ordinary differential equations. Three methods to solve the model are presented and compared. The first one entails application of discrete Grünwald-Letnikov definition of the fractional derivative in the model. Second involves building an analog scheme in the FOMCON Toolbox in MATLAB environment. Third is the method proposed by Edwards. The impact of selected parameters on the model’s response was examined. The effects of substituting selected quantities into a typical input were discussed and compared.

  • Numerical solutions for large deformation problems in geotechnical engineering
    • Jakub Konkol
    2014

    The problem of large deformations often occurs in geotechnical engineering. Numerical modeling of such issues is usually complex and tricky. The chosen solution has to implicate soil-soil and soil-structure interactions. In this paper, a review of the most popular numerical methods for large deformation problems is presented. The Coupled Eulerian-Lagrangian (CEL) method, the Arbitrary Lagrangian-Eulerian (ALE) method, the Smoothed Particle Hydrodynamics (SPH) method, the Particle Finite Element Method (PFEM) and the Material Point Method (MPM) are described. The basic concepts and features of these methods are shown. Also a comparison of these methods in terms of geotechnical engineering is made.