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Search results for: NUMERICAL ANALYSIS
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Numerical simulations of sand behavior using DEM with 2 different descriptions of grain roughness
PublicationW rozdziale przedstawiono wyniki dyskretnych symulacji jednorodnego trójosiowego ściskania piasku przy zastosowaniu metody elementów dyskretnych. Obliczenia wykonano stosując 2 różne opisy szorstkości ziaren: kule z uwzględnieniem momentów kontaktu oraz grona kul. Obliczono energię sprężystą i dysypację plastyczną. Wyniki symulacji numerycznych porównano z wynikami doświadczalnymi.
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Numerical studies on size effects in concrete beams. Architecture Civil Engineering Environment ACEE
PublicationW artykule przedstawiony wyniki obliczeń efektów skali w belkach betonowych podczas zginania. Zastosowano model sprężysto-plastyczny z nielokalnym osłabieniem. Rozkład wytrzymałości na rozciąganie był stochastyczny - przestrzennie skorelowany. Belki były geometrycznie podobne. Wyniki porównano z modelem efektu skali Bazanta.
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Numerical simulation of transient flow in storm sewers using standard and improved mccormack scheme
PublicationProblem przepływu wody w rurach kanalizacji deszczowej wiąże się z pewnymi specyficznymi zjawiskami zachodzącymi w przewodach podczas zjawisk burzowych. Jeśli rury zaczynają być całkowicie wypełnione wodą, można zaobserwować przejście z ruchu ze swobodną powierzchnią do ruchu pod ciśnieniem i odwrotnie. Takie zjawisko można zaobserwować również w kanałach kontrolowanych przez urządzenia sterujące, np. zasuwy. Ponadto ruch szybkozmienny...
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Numerical Investigation of Nuclear Reactor Kinetic and Heat Transfer Fractional Model with Temperature Feedback
PublicationAbstract—In the paper, the numerical results concerning the kinetics and proposed heat exchange models in nuclear reactor based on fractional calculus are presented for typical inputs. Two fractional models are proposed and compared with the model based on ordinary derivative. The first fractional model is based on one of the generalized Cattaneo equations. The second one is based on replacing the ordinary to fractional order of...
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Critical review of propeller performance scaling methods based on model experiments and numerical calculations
PublicationThe article presents the results of experimental and theoretical investigation of propeller scale effects. The objective of this investigation is to test the adequacy of the methods currently used and to develop possible improvement of the methods.New approaches to the problem and new procedures to account for the propeller scale effects are suggested. The description of the underlying experimental and theoretical research is included.
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Experimental and numerical study on polymer element used for reduction of temporary steel grandstand vibrations
PublicationThe purpose of the paper is to analyse the effectiveness of a polymer damper in reduction of a temporary steel grandstand vibrations through the experimental and numerical study. The damper considered in the investigation is constructed out of two L-shape steel members bonded with polymer mass of high damping properties. The element has been installed as a diagonal one at the back part of the structure. The method has been compared...
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Mechanics of mesh implanted into abdominal wall under repetitive load. Experimental and numerical study
PublicationThere are a number of papers discussing medical and mechanical aspects of ventral hernia management. Despite intensive work on the problem understanding, recurrences of the sickness still happen too often. For that reason new aspects of the problem must be considered. In this paper, a change in the abdominal implant’s stiffness is discussed, which is caused by cyclic loading. Such loading influence abdominal implant e.g. while...
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Physical and numerical modelling of flow pattern and combustion process in pulverized fuel fired boiler.
PublicationW 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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Experimental and numerical studies on the mechanical response of a piezoelectric nanocomposite-based functionally graded materials
PublicationThis work presents an experimental study of piezoelectric structures reinforced by graphene platelets, based on the concept of the functionally graded materials (FGMs). The assumed model is a rectangular beam/plate and the composition is due to the Halpin-Tsai rule. The model is also simulated in the Abaqus software which is the first time that such a structure has been modelled in an FEM package. In addition, a mathematical model...
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Experimental and numerical investigation of mercury removal from flue gas by sorbent polymer composite
PublicationThis paper presents an experimental and numerical investigation of the performance of a sorbent polymer composite (SPC) material used for removing mercury from the flue gases in a full-scale industrial installation. The investigated material is an attractive alternative to activated carbon, which is commonly used for this purpose. While the application of the SPC is characterized by high capital expenditures, this technology offers...
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Comparision of two numerical methods for buried steel culverts made of corrugated shell sheets.
PublicationW pracy omawia się dwie metody analizy statycznej obudowy tuneli i przepustów dużej średnicy. Pierwsza z nich, metoda sprężyn polega na modelowaniu ośrodka gruntowego radialnymi sprężynami reprezentującymi odkształcalność gruntu. Drugie podejście oparte jest na zastosowaniu metody elementów skończonych i programu SOFISTIC. W układzie obudowa - grunt obudowę modeluje się zwykłymi ramowymi elementami sprężystymi a otaczający...
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Numerical simulation of rapidly varied water flow in the ´Wild River´ type water slide
PublicationPrzedstawiono numeryczną analizę przepływu w zjeżdżalni wodnej typu "Dzika Rzeka". Jako model matematyczny przyjęto równania przepływu wody płytkiej. Wobec szybkozmiennego ruchu wody do rozwiązania zastosowano metodę objętości skończonych. Numeryczną symulację przepływu wykonano na trójkątnej siatce niestrukturalnej. Wyniki obliczeń porównano z obserwacjami na obiekcie rzeczywistym zainstalowanym w parku wodnym w Sopocie. Dodatkowo...
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Physical and numerical modelling of heat-flow processes in tangentially pulverized fuel-fired boiler
PublicationPraca 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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Research into flows in turbine blade seals. Part III: Numerical calculations versus experiment
PublicationPrzedstawiono wyniki badań doświadczalnych przepływów w uszczelnieniu nadbandażowym stopnia turbinowego, przeprowadzonych na powietrznej turbinie modelowej. Rezultaty te porównano z wynikami badań numerycznych z zastosowaniem programu Fluent.
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Numerical calculations of wall pressures and stresses in steel cylindrical silos with concentric and eccentric hoppers
PublicationArtykuł przedstawia numeryczną analize naprężeń w płaszczu silosa. Porównane zostały wyniki dla silosów o przepływie centrycznym i mimośrodowym.
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Model test and numerical simulations of earth pressure of non-cohesive soil in 3D formulation.
PublicationW pracy przedstawiono wyniki badań modelowych i obliczeń numerycznych parcia gruntu niespoistego w układzie przestrzennym działajacego na sztywną ścia- nę oporową. Podstawowe schematy wyznaczenia parcia gruntu na sztywną ścianę oporową opatre sa na obrocie ściany wokół jej wierzchołka i podstawy. Uzys- kane wyniki obliczeń przedstawiono jako rozkład składowych statycznych i normalnych wzdłuż sciany. Podano również wypadową parcia...
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Model tests and numerical imulations of earth pressure of non - cohesive soil in 3D formulation.
PublicationW artykule przedstawiono wyniki badań modelowych i symulacji numerycznych parcia gruntu działającego na sztywne konstrukcje oporowe. Analizowano stan przestrzennego odkształcenia ośrodka niespoistego. Parcie czynne gruntu za- sypowego wywołano obrotem ściany oporowej wokół osi przechodzącej przez jej górną i dolną krawędź. Przedstawiono rozkład składowej stycznej i normalnej stanu naprężenia na powierzchni ściany wraz z analizą...
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Numerical simulations of localization of deformation in quasibrittle materials within non-local softening plasticity.
PublicationW artykule przedstawiono model sprężysto-plastyczny z nielokalnym osłabieniem do obliczeń lokalizacji odkształceń w materiałach kruchych. Analizę przeprowadzono dla jednoosiowego ściskania i rozciągania. Obliczenia wykonano dla różnych długości charakterystycznych.
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Numerical simulations of triaxial test with sand using DEM. Archives of Hydro-Engineering and Environmental
PublicationW artykule przedstawiono wyniki symulacji badania trójosiowego dlamateriałów granulowanych. Obliczenia wykonano przy zastosowaniu metodyDEM. Pokazano wpływ momentów kontaktowych na wytrzymałoć próbki. Zbadanowpływ parametrów mikroskopowych na zachowanie się materiału. Wynikiporównano z doswiadczeniami.
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Numerical investigations of size effects in notched and un-notched concrete beams under bending
PublicationW artykule przedstawiono wyniki numerycznej analizy efektów skali (efektu deterministycznego i stochastycznego) w belkach betonowych z nacięciem i bez nacięcia poddanych zginaniu z uwzględnieniem lokalizacji odkształceń. Obliczenia wykonano przy zastosowaniu metody elementów skończonych i sprężysto-plastycznego modelu z nielokalnym osłabieniem. Pokazano wpływ wielkości belek betonowych na ich nośność oraz rozkład lokalizacji odkształceń.
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Experimental and numerical investigations of size effects in reinforced concrete beams with steel or basalt bars.
PublicationW artykule przedstawiono wyniki obliczeń efektów skali w belkach betonowych zbrojonych prętami stalowymi i bazaltowymi podczas zginania. Zastosowano model sprężysto-plastyczny z nielokalnym osłabieniem. Rozkład wytrzymałości na rozciąganie był stochastyczny – przestrzennie skorelowany. Belki były geometrycznie podobne. Wyniki porównano z modelem efektu skali Bazanta
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Numerical Modelling of Shear Localization in Granular Bodies using MPM and Non-local Hypoplasticity
PublicationThe 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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Hydrodynamic reanalysis of water temperature and salinity in the Baltic Sea using the PM3D model
Open Research DataThe dataset contains the results of numerical modeling of water temperature and salinity in the Baltic Sea since 1998. A long-term reanalysis was performed using the three-dimensional hydrodynamic model PM3D (Kowalewski and Kowalewska-Kalkowska, 2017), a new version of the M3D model (Kowalewski, 1997). A numerical dynamic-thermodynamic model of sea...
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Mechanical simulation of artificial gravity in torus-shaped and cylindrical spacecraft
PublicationLarge deformations and stress analyses in two types of space structures that are intended for people to live in space have been studied in this research. The structure under analysis is assumed to rotate around the central axis to create artificial gravitational acceleration equal to the gravity on the Earth's surface. The analysis is fully dynamic, which is formulated based on the energy method by using the first-order shear deformation...
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Acoustic streaming caused by some types of aperiodic sound. Buildup of acoustic streaming
PublicationThe analysis of streaming caused by aperiodic sound of different types (switched on at transducer sound or sound determined by initial conditions) is undertaken. The analysis bases on analytical governing equation for streaming Eulerian velocity, which is a result of decomposition of the hydrodynamic equations into acoustic and non-acoustic parts. Its driving force (of acoustic nature) represents a sum of two terms; one is the...
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Arch bridges under test loadings
PublicationThis paper illustrates experience in arch bridges test loadings of the research team of Department of Structural Mechanics and Bridge Structures from the Gdansk University of Technology. The presented calculations results constist the analysis of spatial construction schemes made using the finite elements method (FEM) and its comparison to the field studies. Arch bridges with the longest spans, visualisation of the computational...
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Communication Model Order Reduction in Hybrid Methods Involving Generalized Impedance Matrix
PublicationA novel strategy for the efficient analysis of frequency-domain scattering electromagnetic problems in open and closed domains is presented. A fully automatic model-order reduction technique, called the enhanced reduced-basis method, is applied to increase the efficiency of the hybrid approach, which combines the finite-element and mode-matching methods. Numerical tests show that the proposed algorithm yields reliable and highly...
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Jakub Konkol dr inż.
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Flood Routing by the Non-Linear Muskingum Model: Conservation of Mass and Momentum
PublicationIn this paper, the conservative properties of the Muskingum equation, commonly applied to solve river flood routing, are analysed. The aim of this analysis is to explain the causes ofthe mass balance error, which is observed in the numerical solutions of its non-linear form. The linear Muskingum model has been considered as a semi-discrete form of the kinematic wave equation and therefore it was possible to derive its two non-linear...
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CONSTRUCTION TECHNOLOGY OF TIMBER-FRAME HOUSES RESISTANT TO DYNAMIC LOADS – STUDY ON MODELS OF EXTERIOR WALLS
PublicationThe aim of this paper is to show the numeric representation of experimental studies concerning the behaviour of exterior wall models of a timber-frame house under harmonic loading. A single wall model according to traditional technology of timberframe house walls (filling with mineral wool) was tested. The analysis was conducted for the following frequencies: 0.5 Hz, 1.0 Hz, 2.0 Hz and 5.0 Hz for various values of the specified...
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FEM modelling of stress and strain distribution in weld joints of steel sandwich panels
PublicationThe development of laser welding technology has enabled the mass production of thin-walled structures, including steel sandwich panels. The technology of joining plating panels with stiffeners by welding allows us to create joints with a specific geometry and material properties. In comparison with other types of joints, laser welds are characterized by their specific behaviour under cyclic load and, as a consequence, a different...
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Footbridges. Dynamic Design – Selected Problems
PublicationModern footbridges create challenge in esthetic and structural design. Breaking the proven canons is a recipe for architectural success. However esthetic form has to be also a functional pedestrian bridge. Therefore a good FEM modeling is a key element in engineering part of design. The paper presents selected problems related to the modeling of the dynamic construction of footbridges. Several basic dynamic problems concerning...
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Discrete element method modelling of elastic wave propagation in a meso-scale model of concrete
PublicationThis paper deals with the accurate modelling of ultrasonic wave propagation in concrete at the mesoscopic level. This was achieved through the development of a discrete element method (DEM) model capable of simulating elastic wave signals comparable to those measured experimentally. The main objective of the work was to propose a novel methodology for constructing a meso-scale model of concrete dedicated to the analysis of elastic...
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FEM approach to estimate the behaviour of biocomposite metal-surface coating system
PublicationA three dimensional (3D) model of biocomposite metal-surface coating system, which is influenced byknown external forces, is proposed. This model consists of the metallic substrate (Ti6Al4V) and thehydroxyapatite (HA) coating. Using FEM (finite element method), strain-stress maps of model weregenerated for investigating relations between the extreme stress of HA coating and the magnitude ofexternal force and the thickness of the...
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Experimental Verification of Storm Sewer Transient Flow Simulation
PublicationThe paper focuses mainly on laboratory investigations of transient and transcritical flow in a single pipe of a sewer system. The aim of this paper is to present a comparison between pressure values calculated by an improved McCormack scheme and those measured at the hydraulic laboratory of the Gdansk University of Technology, which were observed inside a pipe in an experiment for water flow with pressurization. The analysis proves...
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Investigation of the Aerodynamics of an Innovative Vertical-Axis Wind Turbine
PublicationThe paper presents the results of an experimental investigation and a three dimensional numerical analysis of the transient aerodynamic phenomena occurring in the innovative modification of classic Savonius wind turbine. An attempt to explain the increased efficiency of the innovative design a comparison with the traditional solution is undertaken. A vorticity measure based on the integral of the velocity gradient tensor second...
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Reduction of Derivative pipeline effort in water turbine
PublicationThe paper presents an approach to evaluate and reduce the effort of the derivative pipeline in a water turbine of a hydrostatic power station in its vulnerable spots. Potential places of the biggest effort of the structure, as well as the coefficient of displacement and safety factor related to them were identified using FEM numerical method. Pipeline reinforcement was designed and made based on FEM analysis. Original technology...
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New Tool for Examining QoS in the VToIP Service
PublicationThis paper is dedicated to the subject of measuring QoS in the Video Telephony over IP (VToIP) service. QoS measurement models in general and then models designed specifically for measuring QoS in the VToIP service are presented. A new numerical tool for examining the quality of VToIP video streams VToIP is described. The tool’s functionality is then put to the test in a number of analysis scenarios. The results and insights gained...
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Weighted difference schemes for systems of quasilinear first order partial functional differential equations
PublicationThe paper deals with initial boundary value problems of the Dirichlet type for system of quasilinear functional differential equations. We investigate weighted difference methods for these problems. A complete convergence analysis of the considered difference methods is given. Nonlinear estimates of the Perron type with respect to functional variables for given functions are assumed. The proof of the stability of difference problems...
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Selected problems of sensitivity and reliability of a jack-up platform
PublicationThe paper deals with sensitivity and reliability applications to numerical studies of an off-shore platform model. Structural parameters and sea conditions are referred to the Baltic jack-up drilling platform. The study aims at the influence of particular basic variables on static and dynamic response as well as the probability of failure due to water waves and wind loads. The paper presents the sensitivity approach to a generalized...
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Electromagnetic Simulations with 3D FEM and Intel Optane Persistent Memory
PublicationAbstract—Intel Optane persistent memory has the potential to induce a change in how high-performance calculations requiring a large system memory capacity are conducted. This article presents what this change may look like in the case of factorization of large sparse matrices describing electromagnetic problems arising in the 3D FEM analysis of passive highfrequency components. In numerical tests, the Intel oneAPI MKL PARDISO was...
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Wiktoria Wojnicz dr hab. inż.
PeopleDSc in Mechanics (in the field of Biomechanics) - Lodz Univeristy of Technology, 2019 PhD in Mechanics (in the field of Biomechanics) - Lodz Univeristy of Technology, 2009 (with distinction) List of papers (2009 - ) Wojnicz W., Wittbrodt E., Analysis of muscles' behaviour. Part I. The computational model of muscle. Acta of Bioengineering and Biomechanics, Vol. 11, No.4, 2009, p. 15-21 Wojnicz W., Wittbrodt E., Analysis of...
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Large deformation modelling of CPT probing in soft soil—pore water pressure analysis
PublicationThis paper presents the results of finite element modelling with Updated Lagrangian formulation of the Cone Penetration Test in soft soil deposit located in Jazowa, Poland. The numerical calculations are carried out for homogenous, normally consolidated, organic soil layer. The Modified Cam Clay constitutive model for soft soil and Coulomb model for interface are used. The study compares the registered pore water pressure distributions...
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ADAPTIVE METHOD FOR THE SOLUTION OF 1D AND 2D ADVECTION-DIFFUSION EQUATIONS USED IN ENVIRONMENTAL ENGINEERING
PublicationThe paper concerns the numerical solution of one-dimensional (1D) and two-dimensional (2D) advection-diffusion equations. For the numerical solution of the 1D advection-diffusion equation a method, originally proposed for solution of the 1D pure advection equation, has been developed. A modified equation analysis carried out for the proposed method allowed increasing of the resulting solution accuracy and consequently, to reduce...
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Wpływ sposobu odwzorowania pojazdu szynowego na odpowiedź dynamiczną przęsła mostowego
PublicationW pracy przedstawiono rezultaty analiz numerycznych oraz badań eksploatacyjnych dwóch przęseł mostowych wymuszonych ruchomym pojazdem szynowym. Pojazd odwzorowano za pomocą czterech modeli uproszczonych: strumienia sił skupionych, strumienia mas skupionych oraz strumieni oscylatorów jedno- i dwumasowych. Analizy numeryczne wykonano przy wykorzystaniu MES. Potrzebne parametry dynamiczne wyznaczono na podstawie wyników identyfikacji...
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Probabilistic sensitivity of limit states of structures. The Monte Carlo simulation
PublicationDesign sensitivity deals with the variation of structural response, implicitly dependent on the design variables of the problem. An attempt is made to implement probabilistic notation in engineering sensitivity analysis. The procedure to implement the sensitivity of a structural limit state to a given basic variable is described in the paper - its main idea, depicted by a flowchart and numerical examples of engineering analysis....
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Thermal Analysis Of Hybrid Microchannel-Microjet Heat Exchanger
PublicationThe paper presents the numerical investigation of a microjet- microchannel cooling module. In which microjets of water are impinging into the microchannels and forming a liquid film on the impingement surface. Applied technology takes benefits from two very attractive heat removal techniques. When laminar jets are impinging on the surface have a very high kinetic energy at the stagnation point, also in microchannels boundary layer...
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STABILITY AND LOAD BEARING CAPACITY OF A BARS WITH BUILT UP CROSS SECTION AND ELASTIC SUPPORTS
PublicationThe present paper is devoted to the numerical analysis and experimental tests of compressed bars with built–up cross section which are commonly used as a top chord of the roof trusses. The significant impact on carrying capacity for that kind of elements in case of out-of-plane buckling is appropriate choice of battens which are used to provide interaction between separate members. Linear buckling analysis results and nonlinear static...
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Jan Suchorzewski dr inż.
PeopleJan Suchorzewski MSc, born 13.03.1990 in Gdańsk, graduated in civil engineering with specialization in engineering structures at Gdańsk University of Technology in 2014, at thye same time begun work at GUT as PhD student working in a project "Analysis of coupled deterministic-statistic size effect in quasi-brittle materials" performing experimental investigation of shear strength of RC-beams and numerical calculations of concrete...
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STAN AWARYJNY TRYBUNY STADIONU W ZIELONEJ GÓRZE WYWOŁANY SYNCHRONICZNYM TAŃCEM KIBICÓW
PublicationW artykule przedstawiono badania i naprawy trybuny stadionu żużlowego w Zielonej Górze narażonej na nadmierne drgania podczas synchronicznego tańca kibiców zwanego „Labado”. W trakcie prac wykonano dwa etapy wzmocnień: za pomocą dodatkowych słupków (zalecenie zespołu z Uniwersytetu Zielonogórskiego) oraz wzmocnienie dodatkowymi stężeniami całej konstrukcji zadaszenia trybuny. W artykule przedstawiono wyniki badań pomiarowych in...