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Wyniki wyszukiwania dla: CRACKS IN WELDS
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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 modelling of stress and strain distribution in weld joints of steel sandwich panels
PublikacjaThe 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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Size effect in concrete beams under bending – influence of the boundary layer and the numerical description of cracks
PublikacjaIn the paper the size effect phenomenon in concrete is analysed. The results of numerical simulations of using FEM on geometrically similar un-notched and notched concrete beams under bending are presented. Concrete beams of four different sizes and five different notch heights under three-point bending test were simulated. In total 18 beams were analysed. Two approaches were used to describe cracks in concrete. First, eXtended...
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Crack identification using wavelets on experimental staticdeflection profiles
PublikacjaArtykuł prezentuje metodę lokalizacji uszkodzeń w belce wspornikowej za pomocą transformaty falkowej statycznej linii ugięcia. Efektywnośc proponowanej techniki jest sprawdzona na podstawie badań eksperymentalnych. Do pomiaru statycznej linii ugięcia proponuje się metodę fotogrametryczną.
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Genetic algorithm for fatique crack detection in Timoshenko beam.
PublikacjaW pracy przedstawiono metodę detekcji peknięć zmęczeniowych w początkowej fazie ich rozwoju. Algorytm detekcji wykorzystuje metodę algorytmów genetycznych połączoną z metodą gradientową. Funkcja celu oparta została o zmiany w propagujacej fali sprężystej.
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Numerical assessment of the fatigue crack propagation in ship structuraldetails.
PublikacjaPrzedstawiono podejście teoretyczne pozwalające na modelowanie rozwoju pęknięcia w konstrukcji kadłuba okrętu. Omówiono założenia i procedurę realizacyjną. Pokazano wyniki badań rzeczywistych modeli konstrukcji kadłuba-skrzyżowanie wiązań ramowych o jednakowej wysokości. Dokonano porównania i krytycznej analizy wyników uzyskanych na drodze teoretycznej z wynikami badań rzeczywistych.
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Crack Resistance of Asphalt Concrete Subjected to Environmental Factors
PublikacjaThe paper presents an analysis of the influence of environmental factors on the cracking susceptibility of asphalt concrete resulting in a change in the durability of asphalt pavement. In order to assess the phenomenon, laboratory tests were carried out taking into account the destructive effects of moisture, freeze-thaw cycle and long-term ageing. The influence of both factors occurring simultaneously was also verified. Due to...
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On stress singularity near the tip of a crack with surface stresses
PublikacjaIn the framework of the simplified linear Gurtin–Murdoch surface elasticity we discuss a singularity of stresses and displacements in the vicinity of a mode III crack. We show that inhomogeneity in surface elastic properties may significantly affect the solution and to change the order of singularity. We also demonstrate that implicitly or explicitly assumed symmetry of the problem may also lead to changes in solutions. Considering...
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Analysis of geometrical layout of tram tracks based on the railway methods
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Optical fibers and photonics applications: topical tracks at Wilga Conferences
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Correction of determined coordinates of railway tracks in mobile satellite measurements
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Correction of determined coordinates of railway tracks in mobile satellite measurements
PublikacjaThis article examines one of the basic issues related to the technique of mobile satellite measurements in railway tracks. This problem concerns the correction of the determined coordinates of the track centerline. The need to perform this operation results from the GNSS receivers positioning at a certain height above the level of the existing track axis, leading to longitudinal and lateral shifts of antennas. The key problem here...
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Calculations of notch stress factor of a thin-walled spreader bracket fillet weld with the use of a local stress approach
PublikacjaPresence of geometric notches in welded joints causes concentration of strains and stresses, therefore reducing fatigue strength of such joints. This article presents an analysis of stress concentrations in a fillet weld of a spreader mounting bracket on a small sailing yacht. The aim of this article is to direct the attention of designers, manufacturers and regulatory bodies to issues of fatigue cracks that form in brackets fastening...
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Comparison of strain results at a laser weld notch obtained by numerical calculations and experimental measurements
PublikacjaIn the development of ship structures applying new materials and it’s purposeful placement play an important role. During the last years, especially in a construction of ro-ro type vessels, the usage of novel sandwich structures in cargo decks is profitable. Steel sandwich panel is an innovative solution which at a todays state of development can be used for the construction of any members not taking part in a global bending of...
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Turning ability of hydrofoil crafts
PublikacjaPrzedstawiono metodę pozwalającą wyznaczać średnicę taktyczną, kąt przechyłu i kąt dryfu oraz siłę poprzeczną na sterze podczas ustalonej cyrkulacji wodolotu. W tym celu opracowano układ równań opisujących ruch wodolotu w płaszczyźnie poziomej. Współczynniki równań są wyznaczane na podstawie głównych parametrów geometrycznych jednostki oraz płatów. Przeprowadzono także szereg obliczeń dla różnych konfiguracji płatów oraz zespołu...
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Crack identification using wavelets on experimental static deflection profiles
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Longitudinal wave propagation. Part II—Analysis of crack influence
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Crack Mouth Opening Displacement for EH36 Shipbuilding Steel Measurements
PublikacjaThe dataset titled EH36 steel for shipbuilding (plate thicnkness 50mm) - CMOD - force record, a0/W = 0.6 contains CMOD (Crack Mouth Opening Displacement) - Force record which is the base for evaluation of fracture toughness of structural steel. Bend specimens witch Bx2B section (B= 50mm), and relative initial crack length a0 / W = 0.60 were used. The test was carried out at ambient temperature in accordance to ISO 12135 standard....
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Longitudinal wave propagation. Part II, Analysis of crack influence
PublikacjaW pracy analizowano wpływ pęknięć zmęczeniowych na propagacje fali wzdłużnej w prętach. Opracowano nowe typy element ów spektralnych oparte na teorii elementarnej, Love'a, Mindlina i trójpostaciowej.
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NONLINEAR VIBRATION ANALYSIS OF BEAM AND PLATE WITH CLOSED CRACK: A REVIEW
PublikacjaThe effect of nonlinearity is high sensitivity in damage detection, especially for closed cracks and delamination. This review illustrates the results of several researchers dealing with nonlinear effects caused by the closure of cracks in the structure, i.e., beam and plate structures. Early detection of damage is an important aspect for the structure and, therefore, continuous progress is being made in developing new and effective...
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Mesoscopic simulations of crack propagation in concrete using cohesive elements
PublikacjaThe paper presents results of two-and three-dimensional meso-scale simulations of fracture in notched concrete beams subjected to three-point bending test. Concrete was assumed as a 3-phase material composed of aggregate grains placed in the cement matrix with Interfacial Transitional Zones (ITZs) between then. In 2D simulations macro-voids were also taken into account. The particle distribution was taken from real concrete beams...
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Fluorescent imaging of heavy charged particle tracks with LiF single crystals
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Luminescent properties of LiF crystals for fluorescent imaging of nuclear particles tracks
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The analysis of tram tracks geometrical layout based on Mobile Satellite Measurements
PublikacjaIn this article, the results of the research in a field of which uses active global navigation satellite system (GNSS) geodetic networks for the inventory of geodetic geometric tram tracks are presented. The applied measurement technique has been adapted for the designing of the geometric layout of tram tracks. Several configurations of receivers and settings of an active GNSS networks with the objective to increase the accuracy...
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Designate CTOD Heat Affected Zone of butt weld, Report No: WOiO/II/76/2013
PublikacjaTypical (normative) testing of materials and/or welded joints do not answer on all questions about material or welded joint properties. In ship building and off-shore sectors, many strucures requires materials and joint with higher than typical fatigue resistance. Imact tests, which are carried out during welding technology qualification, gives answer about ductility, CTOD tests results about material or welded joint ability...
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Fatigue life improvement using low transformation temperature weld material with measurement of residual stress
PublikacjaWelding processes often produce high levels of tensile residual stress. Low transformation temperature (LTT) welding wires utilise phase transformation strains to overcome the thermal contraction of a cooling weld. In this paper, the residual stress within each weld was quantified using the milling/strain gauge method, being the strain change measured as the weldment was milled away. The fatigue tests were conducted under uniaxial...
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Effect of the Post-Weld Surface Condition on the Corrosion Resistance of Austenitic Stainless Steel AISI 304
PublikacjaSurfaces of welded elements made of corrosion-resistant (stainless) steels develop temper colours. The removal of thickened oxide layers off steels exposed to temperatures below 300°C is necessary and entails the restoring of high corrosion resistance of the stainless steel. The article presents tests concerned with the effect of a method applied to remove post-weld temper on the corrosion resistance of austenitic stainless steel...
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Comparison of low-temperature cracks intensity on pavements with high modulus asphalt concrete and conventional asphalt concrete bases
PublikacjaHigh modulus asphalt concrete (HMAC) base courses provide very good resistance to rutting and fatigue but they can increase the risk of low-temperature cracking as compared with conventional asphalt concrete (AC). The article presents the comparison of these two road materials in terms of low-temperature cracking. The statistical method based on the ordered logistic regression model was used. The analysis was based on results of...
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Quantitative assessment of the influence of tensile softening of concrete in beams under bending by numerical simulations with XFEM and cohesive cracks
PublikacjaResults of the numerical simulations of the size effect phenomenon for concrete in comparison with experimental data are presented. In-plane geometrically similar notched and unnotched beams under three-point bending are analyzed. EXtended Finite Element Method (XFEM) with a cohesive softening law is used. Comprehensive parametric study with the respect to the tensile strength and the initial fracture energy is performed. Sensitivity...
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P92 steel and inconel 617 alloy welds joint produced using ERNiCr-3 filler with GTAW process: Solidification mechanism, microstructure, mechanical properties and residual stresses
PublikacjaThe objective of the current study was to analyse the microstructure, mechanical characteristics, and residual stresses of a dissimilar welded joint (DWJ) made of P92 steel and the Inconel alloy 617 (IN617) using the gas tungsten arc welding (GTAW) method. The ERNiCr-3 filler was selected to produce the conventional V groove (VG) and narrow V groove (NVG) butt joint. The filler deficient zones in the weldments, such as the filler...
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Track-to-track fusion in tracking of multiple targets in clutter - a comparative study.
PublikacjaPrzedstawiono i porównano algorytmy rozproszone wyznaczania trajektorii obiektów dynamicznych na podstawie danych z wielu źródeł. Rozważono przypadek, w którym dane dotyczące pozycji obiektów są zakłócone przez dodatkowe fałszywe wykrycia niezwiązane z obserwowanymi obiektami. Algorytmy rozproszone i centralne to dwie podstawowe klasy algorytmów służące do wyznaczania trajektorii obiektów dynamicznych na podstawie danych z wielu...
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Geometry of cycling track
PublikacjaThe paper describes the problems related to shaping of the geometry of the cycling track. The method of selection of the angle at the track curve is presented. Issues related to the selection of the appropriate transition curve and the superelevation section along the transition curve are presented. Reference to the recommendations presented in the literature and scientific papers has been made. Special attention...
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Detection of Closing Crack in Beam Based on Responses Induced by Harmonic Excitation
PublikacjaThe non-linear contact model was chosen to simulate the closed crack in the cantilever beam. The study examines the shape and characteristics of the phase diagram of a cantilever beam with closed cracks. It investigates how various crack properties influence the geometry of the phase diagram and proposes a method for identifying cracks based on their features. The area of each closed curve in the phase diagram is determined using...
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Impedance monitoring of fuel cell stacks
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Impedance monitoring of fuel cell stacks
PublikacjaThis paper presents an innovative, electrochemical impedance method for monitoring of electrochemical behaviour of a multi-cell, direct methanol fuel cell (DMFC) device. This method not only provides classical voltage changes at successive cells but also allows their detailed impedance behaviour to be presented. Impedance characteristics of individual cells within a fuel cell stack (depending on actual operating conditions) are...
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Determination of CWR track's durability characteristics
PublikacjaW pracy przedstawiono wyniki badań nad wyznaczaniem sił osiowych w szynie kolejowej z zastosowaniem metody wymuszonych przemieszczeń poprzecznych. Badania przeprowadzone na stacjonarnym stanowisku badawczym wykazały, że siłę podłużną w szynie można znacznie dokładniej określić na podstawie zmiany nie pionowej, lecz poziomej siły poprzecznej. Pozwoliło to właściwie ukierunkować prace nad określaniem sił osiowych w szynach toru...
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Photos and rendered images of LEGO bricks
PublikacjaThe paper describes a collection of datasets containing both LEGO brick renders and real photos. The datasets contain around 155,000 photos and nearly 1,500,000 renders. The renders aim to simulate real-life photos of LEGO bricks allowing faster creation of extensive datasets. The datasets are publicly available via the Gdansk University of Technology “Most Wiedzy” institutional repository. The source files of all tools used during...
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Analysis of Ceramic Elements with Ring-Crack Defects in Lubricated Rolling Contact
PublikacjaThe properties of ceramics, specifically low density, high hardness, high temperature capability and low coefficient of thermal expansion are of most interest to rolling element manufacturers. Surface ring cracks on lubricating rolling contact fatigue failure has been studied using numerical fracture analysis. Such cracks are very often found on ceramic bearing balls and decrease fatigue life rapidly. The numerical calculations...
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Assessment of crack resistance of ship steels according to SEP 1390 standard
PublikacjaThe aim of the study was to evaluate the weldability of E36 nd NVE-36 steels by bending test according to SEP 1390. In the case of the specimen from E36 steel 9 external cracks were found, 5 of which were stopped in the fusion line and 4 in heat affected zone. In the case of the specimen from NVE-36 steel 8 external cracks were found, 4 of which were stopped in the fusion line and 4 in heat affected zone. Results of bending test...
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Crack Mouth Opening Displacement for EH36 Shipbuilding Steel Measurements Dataset
PublikacjaThe dataset titled EH36 steel for shipbuilding (plate thickness 50 mm) – CMOD – force record, a0/W=0.6 contains a CMOD (Crack Mouth Opening Displacement) – Force record which is the base for evaluation of the fracture toughness of structural steel. Bend specimens with a Bx2B section (B = 50 mm), and relative initial crack length a0/W=0.60 were used. The test was carried out at ambient temperature in accordance with the ISO 12135...
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Detection and size estimation of crack in plate based on guided wave propagation
PublikacjaThe paper presents results of the comprehensive theoretical and experimental investigation of crack detection in metallic plate using guided wave propagation. The main aim of the paper is to develop the novel method which would allow for linear crack size estimation with the use of minimal number of the transducers. In general, there exists the relation between length of the propagation path and the wave amplitude value. However,...
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Accuracy assessment of mobile satellite measurements in relation to the geometrical layout of rail tracks
PublikacjaThe paper presents the campaigns of mobile satellite measurements, carried out in 2009–2015 on the railway and tram lines. The accuracy of the measurement method has been analysed on the basis of the results obtained in both horizontal and vertical planes. The track axis deviation from the defined geometric shape has been analysed in the areas clearly defined in terms of geometry, i.e. on the straight sections and sections with...
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Tyre/road noise measurements on ISO tracks using the modified CPX method
PublikacjaTyre rolling noise test method specified in the UNECE Regulation 117 is directly used in the Tyre Labelling Directive. Noise level specified on EU Tyre Label of each new tyre available on the European market was determined based on vehicle coast-by noise measurements performed on the standard reference road surface proscribed in the ISO 10844:2014. Available data from investigations by the vehicle and tyre industry and results...
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Tyre/road noise measurements on ISO tracks according to the UNECE Regulation 117
PublikacjaWithin the Polish-Norwegian research project ELANORE, a limited Round Robin Test has been performed on 3 ISO tracks in Northern Europe. The basic objective of the project is to improve the EU directive on labelling of tyres for noise and rolling resistance, and this directive is based on the measurement procedures defined in the UN ECE Reg.117. The same test car, test tyres and measurement equipment as well as personnel were used...
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Selecting wells for an optimal design of groundwater monitoring network based on monitoring priority map: A Kish Island case study
PublikacjaThis paper presents a novel approach, i.e. a combination of gamma test and monitoring priority map, for optimal design of groundwater monitoring network (GMN) by considering the cumulative effects of industries, human activities, and natural factors on the groundwater quality. The proposed method was successfully applied to design an optimal network for groundwater salinity monitoring on Kish Island, Persian Gulf. The priority...
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The Impact of Homogeneity of High Modulus Asphalt Concrete Layer on Low-Temperature Cracking
PublikacjaDuring winter season of 2012 numerous transverse cracks developed in high-modulus asphalt concrete (HMAC) base of newly constructed motorway. Pavement cracked both in transverse joint locations and in the area between them. Research which was conducted during investigation of the causes and mechanisms of cracking consisted of: field examination, laboratory testing of specimens cored out of the existing pavement, computational analyses...
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ICHNOS-AN INTERNATIONAL JOURNAL FOR PLANT AND ANIMAL TRACES
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On the Application of Magnetoacoustic Emission for a Nondestructive Assessment of the Post Welding Heat Treatment of High Chromium Steel Weld Seams
PublikacjaThe paper analyses the possibility of post weld heat treatment (PWHT) quality assessment with the help of magnetoacoustic emission (MAE) signal measurements. Two welded superheater tubes, made of high chromium VM12 steel, were analysed—as welded and heat treated one. The analysed sample in the as welded state exhibited significantly higher hardness, accompanied by a big difference in the MAE signal intensity (of order of about...
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Activated Tungsten Inert Gas Weld Characteristics of P91 Joint for Advanced Ultra Supercritical Power Plant Applications
PublikacjaActivated Tungsten Inert Gas (A-TIG) welding, a variant of tungsten inert gas (TIG) welding, was used for welding P91. In Generation IV power plants, P91 welds are prone to premature failure due to the presence and formation of brittle phases and creep at high temperatures. When performing A-TIG welding, the flux composition plays a role in the reversal of the Marangoni flow in the weld pool, which ultimately determines the level...
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Effect of Pendolino high-speed rail on the structure of buildings located the proximity of the railway tracks
PublikacjaThe following research focuses on the dynamic analysis of the impact of the high-speed train inducted vibrations on the structures located near railway tracks. The office complex chosen as the subject of calculations is located in the northern part of Poland, in Gdańsk, in the proximity of Pendolino, the high speed train route. The high speed trains are the response for the growing needs for more efficient railway system. However...