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Search results for: FRACTOGRAPHY FRACTAL DIMENSION FRACTURE STEEL BENDING-TORSION FATIGUE FATIGUE CRACK INITIATION
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Influence of Material Thickness on the Ductile Fracture of Steel Plates for Shipbuilding
PublicationIn the shipbuilding industry, the risk of brittle fractures is relatively high because some units operate in arctic or subarcticzones and use high thickness (up to 100 mm) steel plates in their structures. This risk is limited by employing certifiedmaterials with a specific impact strength, determined using the Charpy method (for a given design temperature) and byexercising control over the welding processes (technology qualification,...
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Microcrack monitoring and fracture evolution of polyolefin and steel fibre concrete beams using integrated acoustic emission and digital image correlation techniques
PublicationThe use of polymer and steel fibres in plain concrete appears to be an excellent solution for limiting crack propagation and improving the post-ductility performance of concrete structures. Based on this premise, this study investigated the fracture evolution of polyolefin fibre-reinforced concrete (PFRC) and steel fibre-reinforced concrete (SFRC) specimens through the integrated application of two diagnostic techniques, acoustic...
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THE EFFECT OF NOTCH DEPTH ON CTOD VALUES IN FRACTURE TESTS OF STRUCTURAL STEEL ELEMENTS
PublicationIn elements of steel structures working at low temperatures, there is a risk of appearance of brittle fracture. This risk is reduced through the use of certified materials having guaranteed strength at a given temperature. A method which is most frequently used to determine brittle fracture toughness is the Charpy impact test, preformed for a given temperature. For offshore structures intended to work in the arctic climat e, the...
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Fatigue of the ship structure.
PublicationZaprezentowano wyniki prac badawczych zachowania paneli SANDWICH pod obciążeniem zginającym. Prace prowadzone były w Kat. Technol. Okrętów i Obiektów Oceanotechn. Wydz. OiO i obejmowały między innymi badania konstrukcji w skali rzeczywistej. Dokonano porównania uzyskanych rezultatów z wynikami prezentowanymi w literaturze.
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On the crack front curvature in bonded joints
PublicationStandard tests of adhesively bonded specimens are likely to produce heterogeneous stress distribution along the crack front and its vicinity. High separation rate mode I dominated fracture test is performed.Observation of post mortem fractured surfaces with an optical microscope reveals characteristic features of mixed mode I/III fracture near the sides of the specimen but not in the middle. At first, finite elements calculations...
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Fracture simulations in concrete beam under bending using a mesoscopic model with cohesive elements
PublicationThe main aim of this paper was to investigate a complex fracture process in a concrete beam subjected to 3-point bending test by means of the 2D meso-scale FEM with 4-node cohesive elements embedded in the initial mesh of 3-node solid elements. The material heterogeneity was taken into account by considering 3 different phases (aggregate, cement matrix, ITZs) on the basis of randomly generated internal structure of concrete and...
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Fatigue data of Cement Bitumen Treated Material Mixture C3E5.5 (over 28 days of curing at 20C)
Open Research DataFatigue data of Cement Bitumen Treated Material Mixture C3E5.5 (over 28 days of curing at 20C)
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Analysis of loading history influence on fatigue and fracture surface parameters using the method of induction trees
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Strain sequence effect on fatigue life and fracture surface topography of 7075-T651 aluminium alloy
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SIMULATIONS OF FRACTURE IN CONCRETE BEAMS UNDER BENDING USING A CONTINUUM AND DISCRETE APPROACH
PublicationThe paper describes two-dimensional meso-scale results of fracture in notched concrete beams under bending. Concrete was modelled as a random heterogeneous 4-phase material composed of aggregate particles, cement matrix, interfacial transitional zones and air voids. Within continuum mechanics, the simulations were carried out with the finite element method based on a isotropic damage constitutive model enhanced by a characteristic...
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Advanced fatigue and rutting characterisation of Polish asphalt mixtures based on the VECD model and viscoplastic shift model
PublicationThe advanced asphalt mixture performance-related specifications (AM-PRS) recently developed in USA can allow an optimisation of the design process of asphalt pavements thanks to the possibility to fully take into account the intrinsic material properties. In this study, four typical Polish mixtures, i.e. a Stone Mastic Asphalt (SMA) for wearing course, two mixtures for binder course with neat bitumen or Polymer modified Bitumen...
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Sensivity of echo envelope fractal dimension to bottom type and bottom depth.
PublicationPrzedstawiono wynik badania zależności pomiędzy wymiarem fraktalnym obwiedni echa akustycznego od dna a rodzajem dna na wpływ głębokości dna na tę zależność. Wykorzystano sygnały ech otrzymane w wyniku numerycznych symulacji rozpraszania na granicy woda dno dla różnych głębokości dna.
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Fatigue tests of steel Sandwich panel. Fifth International Conference on Marine Technology and Transportation.
PublicationW referacie przedstawiono wyniki badań laboratoryjnych paneli SANDWICH prowadzonych w Katedrze Technologii Okrętów, Systemów Jakości i Materiałoznawstwa Wydziału OiO na konstrukcjach w skali rzeczywistej. Dokonano porównania uzyskanych rezultatów w wynikami prezentowanymi w literaturze.
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Crack propoagation in MgO-PSZ ceramic materials
PublicationThe properties of ceramic materials such as elevated hardness, high temperature capability, low coefficient of thermal expansion are of interest for rolling element materials. Widely used ceramic materials in engineering applications are silicon nitride, zirconia and alumina. The paper presents an experimental study of the fatigue life of MgO-PSZ ceramic material in lubricated contact with defined types of cracks. A ceramic angular...
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ENERGY ANALYSIS OF THE PROPULSION SHAFT FATIGUE PROCESS IN A ROTATING MECHANICAL SYSTEM PART III DIMENSIONAL ANALYSIS
PublicationThis article presents the third and last part of the problem of diagnosing the fatigue of marine propulsion shafts in terms of energy with the use of the action function, undertaken by the authors. Even the most perfect physical models of real objects, observed under laboratory conditions and developed based on the results of their research, cannot be useful in diagnostics without properly transferring the obtained results to the...
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Crack monitoring in concrete beams under bending using ultrasonic waves and coda wave interferometry: the effect of excitation frequency on coda
PublicationConcrete is one of the most widely used construction materials in the world. In recent years, various non-destructive testing (NDT) and structural health monitoring (SHM) techniques have been investigated to improve the safety and control of the current condition of concrete structures. This study focuses on micro-crack monitoring in concrete beams. The experimental analysis was carried out on concrete elements subjected to three-point...
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A continual model of a damaged medium used for analyzing fatigue life of polycrystalline structural alloys under thermal–mechanical loading
PublicationThe main physical laws of thermal–plastic deformation and fatigue damage accumulation processes in polycrystalline structural alloys under various regimes of cyclic thermal–mechanical loading are considered. Within the framework of mechanics of damaged media, a mathematical model is developed that describes thermal–plastic deformation and fatigue damage accumulation processes under low-cycle loading. The model consists of three...
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FATIGUE TESTING MACHINES AND APPARATUS
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Fatigue data of Cement Bitumen Treated Material Mixture C3E5.5 (Direct tension, over 28 days of curing at 20C)
Open Research DataFatigue data of Cement Bitumen Treated Material Mixture C3E5.5 (Direct tension, over 28 days of curing at 20C)
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Corrigendum to “An investigation on residual stress and fatigue life assessment of T-shape welded joints” [Eng. Fail. Anal. 141 (2022) 106685]
PublicationThis paper aims to quantitatively evaluate the residual stress and fatigue life of T-type welded joints with a multi-pass weld in different direction. The main research objectives of the experimental test were to test the residual stress by changing direction along with multiple wielding passes and determine the fatigue life of the welded joints. The result shows that compressive residual stress increases in the sample gradually...
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The determination of deformations and stresses of laser welds used for fatigue assessment of steel sandwich panel joints
PublicationPanele typu sandwich znajdują szerokie zastosowanie w wielu gałęziach przemysłu. W przypadku niektórych zastosowań wymagających ocenę ryzyka dużą rolę odgrywa ocena trwałości zmęczeniowej spoin laserowych paneli. W pracy prezentowane są metody wyznaczania lokalnych odkształceń i naprężeń w połączeniach spawanych w celu oceny trwałości zmęczeniowej według hipotez lokalnych naprężeń i odkształceń.
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Waves Along Fractal Coastlines: From Fractal Arithmetic to Wave Equations
PublicationBeginning with addition and multiplication intrinsic to a Koch-type curve, we formulate and solve wave equation describing wave propagation along a fractal coastline. As opposed to examples known from the literature, we do not replace the fractal by the continuum in which it is embedded. This seems to be the first example of a truly intrinsic description of wave propagation along a fractal curve. The theory is relativistically...
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Janusz Kozak prof. dr hab. inż.
PeopleJanusz KOZAK Born 04.07.1953 Puck, Poland Intermediate school” Technikum Budowy Okrętów „Conradinum” Gdansk, 1973. Graduated on Faculty of Shipbuilding of Gdańsk University of Technology, Poland, 1978. Employed: From 1978 - Gdynia Shipyard 1978 as designer, from 1980 as a specialist in Chair of Technology in Faculty of Shipbuilding of Gdańsk University of Technology, 1993 as assistant, PhD (1993), “Method for assessment...
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Fatigue data of Cement Bitumen Treated Material Mixture C3E5.5 (over 28 days of curing at 20C, field cores)
Open Research DataDataset presents data of fatigue life determined for cold recycled mixture – cement bitumen treated material mixture with following binding agents: 3% cement and 5.5% emulsion (C3E5.5). Mixture was designed according to Polish requirements for the base course of pavement. Mixture contains 60% of RAP material. Specimen size: f=100 mm, h=48,4 - 70,9 mm.
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Mechanical and fracture properties of concrete reinforced with recycled and industrial steel fibers using Digital Image Correlation technique and X-ray micro computed tomography
PublicationPaper presents investigation of fracture phenomenon in plain concrete and in concrete reinforced with both recycled steel fibers (RSF) and industrial steel fibers (ISF). The wedge splitting test (WST), which enables stable crack propagation for quasi-brittle materials, was carried out on 75 75 75 mm cube samples. Initially, fracture process zone development was investigated only on the surface of samples using Digital Image Correlation...
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Fatigue investigation of plain journal bearings
PublicationW artykule przedstawiono wybrane wyniki badań nad wytrzymałością zmęczeniową warstw ślizgowych w panwiach łozysk poprzecznych, prowadzonych w laboratorium tribologicznym Katedry Konstrukcji i Eksploatacji Maszyn Politechniki Gdańskiej. Opisano stanowiska badawcze i metodykę planowania eksperymentów oraz procedurę opracowywania wyników testów zmęczeniowych. Przedstawiono zamierzenia badawcze w zakresie przedmiotowych badań zmęczeniowych.
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Higuchi fractal dimension analysis of surface EMG signals and determination of active electrode positions
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Fatigue Damage Development in 14MoV6-3 Steel for Power Plant Pipes Monitored by Digital Image Correlation
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Effect of high temperature exposure on the fatigue damage development of X10CrMoVNb9-1 steel for power plant pipes
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Application of the theory of energy transformation systems to fatigue assessment of steel elements under multiaxial periodic loading
PublicationPraca dotyczy symulacji odporności zmęczeniowej elementów stalowych poddanych wieloosiowym obciążeniom okresowym w zakresie wysokocyklowym. W tym celu zdefiniowano jednoosiowe naprężenie sinusoidalne, równoważne w sensie trwałości zmęczeniowej materiału naprężeniu aktualnemu gdy każda jego kartezjańska składowa jest dana w postaci szeregu Fouriera. Warunki równoważności wynikają z teorii systemów transformacji energii i wiążą się...
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Comparison of different one-parameter damage laws and local stress-strain approaches in multiaxial fatigue life assessment of notched components
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ENGINEERING FRACTURE MECHANICS
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Topography measurement methods evaluation for entire bending-fatigued fracture surfaces of specimens obtained by explosive welding
PublicationIn this paper, the methods of compensation of differences in the results of entire bending-fatigued fracture surface topographies were presented. The roughness evaluation was performed with a focus variation microscope and confocal surface topography measurement techniques. The differences in the ISO 25178 roughness parameters were investigated and procedures for their compensation were studied. It was found that various types...
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Mechanical properties of VL E27 steel for shipbuilding – fracture toughness test in 0°C
Open Research DataOne of the basic divisions of steels used for ship hulls and ocean engineering structures is the division into: normal strength steels, high strength steels and extra high strength steels. The belonging to the group is determined by the mechanical properties of the steel, such as: yield point, ultimate strength and plastic elongation after fracture....
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Mechanical properties of VL E27 steel for shipbuilding – fracture toughness test in 20°C
Open Research DataOne of the basic divisions of steels used for ship hulls and ocean engineering structures is the division into: normal strength steels, high strength steels and extra high strength steels. The belonging to the group is determined by the mechanical properties of the steel, such as: yield point, ultimate strength and plastic elongation after fracture....
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Mechanical properties of VL E27 steel for shipbuilding – fracture toughness test in -20°C
Open Research DataOne of the basic divisions of steels used for ship hulls and ocean engineering structures is the division into: normal strength steels, high strength steels and extra high strength steels. The belonging to the group is determined by the mechanical properties of the steel, such as: yield point, ultimate strength and plastic elongation after fracture....
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Investigation on Mode I Fracture Behavior of Hybrid Fiber-Reinforced Geopolymer Composites
PublicationRecent reports in the literature have shown that fber-reinforced geopolymer composites (FRGC) made with monofbers exhibit a signifcant enhancement in fracture energy. However, many aspects of the fracture performance of hybrid fberreinforced geopolymer composites (HFRGC) remain largely unexploited, and these are predominant for the structures. For the frst time, the mode I fracture energy of HFRGC is investigated. The mode I behavior...
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The effect of external load on ultrasonic wave attenuation in steel bars under bending stresses
PublicationThe stress state in deformed solids has a significant impact on the attenuation of an ultrasonic wave propagating through the medium. Measuring a signal with certain attenuation characteristics can therefore provide useful diagnostic information about the stress state in the structure. In this work, basic principles behind a novel attenuation-based diagnostic framework are introduced. An experimental study on steel bars under three-point...
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Ograniczenie trwałości skojarzeń ceramicznych w wyniku propagacji pęknięć powierzchniowych = Fatigue life limitation of ceramic materials due to surface crack propagation
PublicationPrzedstawiono krótką analizę literaturową dotyczącą mechanizmów propagacji pęknięć w materiałach ceramicznych oraz wyniki dotychczasowych badań doświadczalnych wybranych materiałów ceramicznych z uwzględnieniem wpływu pęknięć powierzchniowych na trwałość ceramicznych skojarzeń tocznych.
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Suitability of DIC and ESPI optical methods for monitoring fatigue damage development in X10CrMoVNb9-1 power engineering steel
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Mesoscopic simulations of crack propagation in concrete using cohesive elements
PublicationThe 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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Forecasting of fatigue life of laser welded joints
PublicationW pracy przedstawiono podstawowe dane na temat stalowych paneli typu sandwich. Zaprezentowano wyniki testów zmęczeniowych elementarnych połączeń teowych spawanych laserowo. Omówiono szczegółowo te cechy, które mają istotny wpływ na statyczne i zmęczeniowe własności złącza. Na podstawie przedstawionych wyników badań zmęczeniowych elementarnych połączeń spawanych laserowo uzyskano krzywą projektową S-N dla jednego z pokazanych modeli...
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Increasing rail life by forecasting fatigue failure.
PublicationReferat poświęcony jest przedłużaniu żywotności szyn i obejmuje zagadnienia prognozowania liczby pęknięć a także planowania szlifowań szyn. Dane pomiarowe pochodzą z wieloletnich badań przeprowadzonych w Katedrze Inżynierii Kolejowej Politechniki Gdańskiej na liniach magistralnych PKP.
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Fatigue criterial parameters of variable amplitude stress.
PublicationPrzedstawiono oryginalne kryterialne parametry zmęczeniowe naprężenia o zmiennej amplitudzie. Dla ich wyznaczenia założono, że wydatkowana w procesie zmęczenia energia jest proporcjonalna do energii sprężystego odkształcenia postaciowego. Jeżeli przyrost zniszczenia spowodowanego przez nj cykli naprężenia o stałej amplitudzie aj jest odniesiony do energii sprężystego odkształcenia postaciowego przekazanej jednostkowej objętości...
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Effect of pavement roughness and vehicle dynamic loads on decrease of fatigue life of flexible pavements
PublicationDue to the fact that pavement surfaces are not ideally even, dynamic loads of vehicle axles deviate from static loads. Higher dynamic loads contribute to faster pavement distress. The distribution of dynamic loads is similar to normal distribution and can be described by static load and factors DI (dynamic impact) and DLC (dynamic load coefficient). With the deterioration of pavement condition its evenness decreases as well and...
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Mechanical properties of VL E27 steel for shipbuilding – 3D model of fracture (test in +20°C)
Open Research DataOne of the basic divisions of steels used for ship hulls and ocean engineering structures is the division into: normal strength steels, high strength steels and extra high strength steels. The belonging to the group is determined by the mechanical properties of the steel, such as: yield point, ultimate strength and plastic elongation after fracture....
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Mechanical properties of VL E27 steel for shipbuilding – 3D model of fracture (test in 0°C)
Open Research DataOne of the basic divisions of steels used for ship hulls and ocean engineering structures is the division into: normal strength steels, high strength steels and extra high strength steels. The belonging to the group is determined by the mechanical properties of the steel, such as: yield point, ultimate strength and plastic elongation after fracture....
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Mechanical properties of VL E27 steel for shipbuilding – 3D model of fracture (test in -20°C)
Open Research DataOne of the basic divisions of steels used for ship hulls and ocean engineering structures is the division into: normal strength steels, high strength steels and extra high strength steels. The belonging to the group is determined by the mechanical properties of the steel, such as: yield point, ultimate strength and plastic elongation after fracture....
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Analiza trwałości zmęczeniowej asfaltów drogowych i modyfikowanych z wykorzystaniem testu liniowego zwiększania amplitudy / Analysis of the fatigue life of neat and modified bitumens using linear amplitude sweep test
PublicationThe paper presents an evaluation of the fatigue resistance of selected Polish bituminous binders: neat bitumen 50/70, polymer modified bitumen PMB 45/80-55 and polymer highly modified bitumen PMB 45/80-80. The linear amplitude sweep (LAS) test, which is a new bitumen performance grading test developed in the USA, and was used to assess the fatigue life of the bitumens. Highly modified bitumen 45/80-80 showed 10-20 times higher...
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Mechanical properties of VL E27 steel for shipbuilding –SEM fracture investigation (Charpy test in -50°C)
Open Research DataOne of the basic divisions of steels used for ship hulls and ocean engineering structures is the division into: normal strength steels, high strength steels and extra high strength steels. The belonging to the group is determined by the mechanical properties of the steel, such as: yield point, ultimate strength and plastic elongation after fracture....