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Analysis of ring cracks in ceramic rolling elements using the boundary element method
PublikacjaCeramic materials have been increasingly used in bearing technology for over a dozen years. This is due to the characteristic properties of ceramic materials such as: high hardness, corrosion resistance, the possibility of use in aggressive chemical environments, as well as due to the lower specific weight compared to steel materials. However, the use of ceramic materials is connected with many limitations. The main disadvantages...
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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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Process zone in the Single Cantilever Beam under transverse loading. - Part I: Theoretical analysis
PublikacjaSingle Cantilever Beam (SCB) specimen loaded with a transverse force parallel to the crack front is proposed for the analysis of crack propagation phenomena under mixed mode conditions. The stress redistribution in the adhesive layer in the vicinity of the crack front so as the beam deformation are estimated using a Timoshenko beam on elastic foundation model. This model emphasizes the Mode II contribution due to flexural beam...
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Artificial neural network based fatigue life assessment of friction stir welding AA2024-T351 aluminum alloy and multi-objective optimization of welding parameters
PublikacjaIn this paper, the fracture behavior and fatigue crack growth rate of the 2024-T351 aluminum alloy has been investigated. At first, the 2024-T351 aluminum alloys have been welded using friction stir welding procedure and the fracture toughness and fatigue crack growth rate of the CT specimens have been studied experimentally based on ASTM standards. After that, in order to predict fatigue crack growth rate and fracture toughness,...
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Investigations on fracture in reinforced concrete beams in 3-point bending using continuous micro-CT scanning
PublikacjaThis study explores a fracture process in rectangular reinforced concrete (RC) beams subjected to quasi-static three-point bending. RC beams were short and long with included longitudinal reinforcement in the form of a steel or basalt bar. The ratio of the shear span to the effective depth was 1.5 and 0.75. The focus was on the load–deflection diagram and crack formation. Three-dimensional (3D) analyses of the size and distribution...
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Smart Growth – Is It a Fairy Tale or the Best Initiative for Polish Cities and Their Functional Regions?
Publikacja.
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Uniwersyteckie Centrum Kompetencyjne Technologii Oprogramowania
PublikacjaPoniższy rozdział stanowi rodzaj case study, gdzie na przykładzie Uniwersyteckiego Centrum Kompetencyjnego Technologii Oprogramowania funkcjonującego przy Politechnice Gdańskiej przedstawiona została koncepcja powoływania i funkcjonowania centrów rozwijania technologii informatycznych tworzony przy uczelniach wyższych przy współpracy z partnerami biznesowymi. Przedstawione zostały potrzeby powoływania takich jednostek organizacyjnych,...
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Smart growth - is it a fairytale or the best initiative for polish cities and their functional regions?
PublikacjaThe paper presents smart growth perceived as natural step in sustainable development understanding.
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Semantyczny portal wiedzy środowiskiem wsparcia procesów integracji uczelni i biznesu
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Optimization model of agile team’s cohesion
PublikacjaTeam’s cohesion is one of the most important factors of IT project execution effectiveness. Optimization of team’s cohesion gives the possibility of reducing the risk of project failure. It also allows to increase the teamwork efficiency and thus optimize time of tasks execution, increase the guarantee of maintaining the scope of the project and the chance of achieving a given level of products quality. This article presents determination...
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Prospects in elongation of railway transition curves
PublikacjaThe paper presents an analysis of the elongation of transition curves in relation to railway track alignment correction and modernisation. The analysis is based on numerical computations for a wide range of parameters describing a typical railway geometrical layout with transition curves. The differences between the horizontal ordinates of the existing layout and the layout with the elongated transition curves are evaluated and...
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Performance of isotropic constitutive laws in simulating failure mechanisms in scaled RC beams
PublikacjaResults of numerical calculations of reinforced concrete (RC) beams are presented. Based on experimental results on longitudinally reinforced specimens of different sizes and shapes are investigated. Four different continuum constitutive laws with isotropic softening are used: one defined within continuum damage mechanics, an elasto-plastic with the Rankine criterion in tension and the Drucker-Prager criterion in compression, a...
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Accurate and continuous adhesive fracture energy determination using an instrumented wedge test
PublikacjaThe wedge test and the related double cantilever beam test are practical methods of assessing structural adhesive fracture energy. In the former, and to a lesser extent the latter, a recognised problem is the difficulty of following the length of the growing crack, required to calculate fracture energy with any accuracy. We present a novel method of measurement of crack length that has the advantages of being accurate and allowing...
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Design of compound curves adapted to the satellite measurements
PublikacjaThe paper deals with a novelty related to the design of a region for an alternative railway track direction adequate for mobile satellite measurements. The new approach may become particularly useful in the design of the existing track axis control when the determination of both the main track directions becomes impossible. The only solution in that case is to apply to the geometrical system two circular arcs of a different radius,...
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Process zone in the Single Cantilever Beam under transverse loading. - Part II: Experimental
PublikacjaThis paper describes an experimental arrangement to evaluate stress/strain fields in the process zone of asymmetric adhesively bonded joints. A transparent polycarbonate flexible beam was bonded to an aluminium alloy rigid block with an epoxy adhesive in a Single Cantilever Beam (SCB) configuration. The flexible adherend was loaded in the direction parallel to the initial crack front at constant rate. To monitor strains induced...
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The process of identification of the track's geometrical layout and the alignment project based on the of satellite measurements
PublikacjaIn the paper a methodology of restoring of railway track’s geometrical shape in a horizontal plane on the base of conducted mobile satellite surveying was presented. The authors proposed a calculating algorithm for designing the track sections placed in horizontal arcs. In the algorithm an analytical methodology with mathematical formulas is applied. The procedure has an universal character, i.e. provides the possibility of varying...
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Kształtowanie toru zwrotnego rozjazdu z odcinkami krzywizny liniowej
PublikacjaW pracy została przedstawiona analityczna metoda kształtowania toru zwrotnego rozjazdu kolejowego posiadającego na swojej długości odcinki krzywizny liniowej. Odróżnia go to w istotny sposób od rozwiązania typowego, stanowiącego pojedynczy łuk kołowy bez krzywych przejściowych. W metodzie tej dokonano identyfikacji problemu rozkładu krzywizny za pomocą równań różniczkowych. Uzyskane rozwiązania mają charakter uniwersalny; m. in....
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Non-uniqueness of fracture parameter choice in simulations of concrete cracking at mesoscale level
PublikacjaIn the paper a non-uniqueness of fracture parameter choice in simulations of cracking process in plain concrete specimens at mesoscale level under monotonic static loading is analysed. The Finite Element Method is used, where cracks are defined in a discrete way using interface cohesive elements with nonlinear material law including softening. The concrete mesostructure (such as: cement matrix, air voids, aggregates, and Interfacial...
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Safety at railway level crossings and Vision Zero
PublikacjaIn this work, safety analysis at the railway level crossings is presented using advanced mathematical modelling. Resistivity of track subgrade panels is taken into account. The analysis does not refer to the assessment of the current regulations. Specific cases of generalized dynamic system are considered by introducing operations S=Δ, S=P defined in space C(N) of real sequences. In this model, generalized discrete exponential...
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Assessment of Subsoil Subsidence Under the Railway Surface with the Use of Fuzzy Sets
PublikacjaThe cause of the subsidence of the railway track is the subsidence of the track bed itself and it is often related to the subsidence of the subsoil. Such settlement leads to: uneven longitudinal railways and track twist. These phenomena have a negative impact on the comfort and safety of driving, and in extreme cases lead to a train derailment. It has been shown that the magnitude of these settlements is determined by many parameters...
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Influence of permanent magnetic field on wear performance of dry sliding contacts
PublikacjaResults of experimental studies concerning the influence of permanent magnetic field on wear of dry sliding contact are presented.It was found that magnetic field of horizontal orientation is causing temporary reduction of material's hardness. It also facilitates and accelerates removal process of wear particles from the contact zone.Formation of bulges, consisting of accumulated and compacted anti-ferromagnetic material produced...
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Multiaxial Fatigue Behaviour of SLM 18Ni300 Steel
PublikacjaFatigue behaviour of SLM 18Ni300 steel under proportional bending-torsion loading is studied. The fatigue tests are conducted under pulsating loading conditions using tubular specimens with a transversal circular hole. Three ratios of the normal stress to shear stress are considered, namely σ/τ=4,σ/τ=2 and σ/τ = 4/3. Crack initiation sites were found for two diametrically opposite points around the hole, whose locations are governed...
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Impact response of novel layered two stage fibrous composite slabs with different support type
PublikacjaThe performance of novel Layered Two Stage Fibrous Composite slabs (LTSFC) was pioneered under falling mass collisions using a combined experimental and numerical study. Such LTSFC slabs consist of three layers with and without the insertion of glass fibre mesh between the layers. LTSFC techniques were used to fabricate the composite slabs with three layers including 3%, 1.5%, and 3% of fibre content for the top, middle, and...
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Opinia techniczna rozjazdu zwyczajnego Rz 49E1-190-1:9 z szynami ochronnymi
PublikacjaOpinia techniczna rozjazdu zwyczajnego Rz 49E1-190-1:9 z szynami ochronnymi dla firmy TRACK TEC KOLTRAM
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Tonality Estimation and Frequency Tracking of Modulated Tonal Components
PublikacjaA novel method for tonality estimation and frequency tracking of tonal components modulated in frequency and amplitude is presented. The algorithm detects the local maxima of magnitude spectra corresponding to three contiguous frames of a signal and matches them into the tonal track candidates. The magnitude-based and phase-based methods are used to estimate the frequency jumps between spectrum maxima belonging to the tonal track...
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Network society: a concept of smart information management
PublikacjaAutomatic enhancement of Internet broadcasted news has been recently gaining increasing importance and interest. Existing applications and models of textual Event Detection in online media are based on the analysis of news distributed via RSS (Rich Site Summary called also Really Simple Syndication) channels or available at news websites. It assumes that each piece of news is equally available to the reader and, therefore, describes...
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Research project BRIK: development of an innovative method for determining the precise trajectory of a railway vehicle
PublikacjaIn the paper the essential assumptions regarding a research project implemented by a consortium of Gdansk University of Technology and Gdynia Maritime University are presented. The project has been commissioned by National Center of Research and Development with cooperation with Polish Railways (PKP Polskie Linie Kolejowe S.A.). The project is focused in implementation of modern measurement techniques using Global Navigation Positioning...
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DYNAMIC ANALYSIS OF HISTORIC RAILWAY BRIDGES IN POLAND IN THE CONTEXT OF ADJUSTING THEM TO PENDOLINO TRAINS
PublikacjaThe article presents the dynamic analysis of the historic railway bridge in Tczew as an example of the usefulness of such type of bridge for high-speed trains. The model of the bridge and the simulation of rolling stock passage was performed in SOFISTIK program. The scope of work includes experimental studies, the solution of the problem concerning the correct solution features dynamic model takes into account the dependencies...
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Fracture of aluminium joints bonded with epoxy adhesive reinforced by mmt nanoparticles
PublikacjaCrack propagation behavior was studied for aluminium/aluminum adhesive joints bonded with two epoxy adhesives: pure and reinforced with clay nanoparticles. The focus was also on the novel use of the constant displacement rate test to study adhesion/adhesives efficiency. The epoxy systems studied were: Epidian E6 produced from bisphenol A and epichlorohydrin, (''Organika -Sarzyna'' Poland); pure or strengthened with montmorillonit...
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Two tests for adhesive bonding long term characterization: principles and applications
PublikacjaThis article describes recent refinement of the traditional wedge test technique used to characterize durability of the adhesive joints. We propose two types of measuring protocols to monitor precisely and continuously the propagation of an "effective" crack during long term mode I fracture mechanic test. First method is directly derived from the traditional wedge test technique and consist in monitoring the surface strain of adherent...
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Release Kinetics Studies of Early-Stage Volatile Secondary Oxidation Products of Rapeseed Oil Emitted during the Deep-Frying Process
PublikacjaThe research concerns the use of proton transfer reaction mass spectrometer to track real-time emissions of volatile secondary oxidation products released from rapeseed oil as a result of deep-frying of potato cubes. Therefore, it was possible to observe a sudden increase of volatile organic compound (VOC) emissions caused by immersion of the food, accompanied by a sudden release of steam from a potato cube and a decrease of the...
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EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF CONCRETE BEHAVIOUR AT MESO-LEVEL DURING QUASI-STATIC SPLITTING TENSION
PublikacjaThe paper describes experimental and numerical results of quasi-static splitting tensile tests on concrete specimens at meso-scale level. The loading strip was made of plywood or steel. Fracture in concrete was detected at the aggregate level by means of three non-destructive methods: 3D x-ray micro-computed tomography, 2D scanning electron microscope and manual 2D digital microscope. The discrete element method was used to directly...
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Capacity Transforming challenges into opportunities
PublikacjaThe Urban Initiative Laboratory (UIL) aims to upgrade the smart city concept in Gdańsk by introducing the Food-Water-Energy (FWE) nexus to the city. It was agreed in the CRUNCH international consortium that projects on different scales would be implemented in the individual countries to test the Integrated Decision Supportive system platform, which would, in principle, concern urban scale. The regular urban scale was to be researched...
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Uniwersalna metoda projektowania regulacji osi toru z wykorzystaniem pomiarów satelitarnych i optymalizacji
PublikacjaW pracy zwrócono uwagę na ograniczenia stosowanej w naszym kraju metodyki regulacji osi toru związane w głównym stopniu z uzyskiwaną dokładnością określania istniejącego kształtu toru. Jako rozwiązanie alternatywne wskazano opracowaną przez interdyscyplinarny zespół naukowy Politechniki Gdańskiej i Akademii Marynarki Wojennej / Akademii Morskiej w Gdyni i stosowaną od 2009 roku nowatorską technikę mobilnych pomiarów satelitarnych....
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Investigation on Mode I Fracture Behavior of Hybrid Fiber-Reinforced Geopolymer Composites
PublikacjaRecent 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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Fracture in Asymmetric Bonded Joints
PublikacjaAdhesion was studied in asymmetric bonded joints using fracture mechanics tests. The asymmetric bonded joints consist of two different type and/or thickness materials bonded by an adhesive. Mentions of asymmetric bonded joint tests employed so far are rare in the literature. They are imperfect and therefore are not standardized. Accordingly three new tests were introduced in this work to study bonded joints. The new metrological...
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Coda wave interferometry in monitoring the fracture process of concrete beams under bending test
PublikacjaEarly detection of damage is necessary for the safe and reliable use of civil engineering structures made of concrete. Recently, the identification of micro-cracks in concrete has become an area of growing interest, especially using wave-based techniques. In this paper, a non-destructive testing approach for the characterization of the fracture process was presented. Experimental tests were made on concrete beams subjected to mechanical...
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Earthworks calculations due to reconstruction of railway geometrical layout
PublikacjaThe paper characterizes continuation of ongoing work of computer program MUGO which is connected with earthworks. The program is related to the modernization of the railway track layout. The methodology for the calculating the size of earthworks in the areas of embankments on the two way railway line is discussed in detail.
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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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IR-THERMAL IMAGING IN CARDIOSURGERY
PublikacjaA method for monitoring the state of the myocardium during cardiosurgical interventions based on thermal IR imaging is presented. These methods called Static Thermography and Active Dynamic Thermography (ADT) uses information about distribution of temperature on the surface and an external excitation source to induce thermal transient processes in a tested object. Recording time series of thermograms allows to calculate parametric...
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LCF behavior of 2024AA under uni- and biaxial loading taking into account creep pre-deformation
PublikacjaThis study presents the results of experimental low-cycle fatigue (LCF) tests of aluminum 2024 alloy T3511 temper in uni- and biaxial loading states. Tests were carried out on both the as-received material (hardened extruded rods) and material with different pre-deformation histories. These deformations were carried out in the creep process at 200 °C and 300 °C for two different levels of at each temperature. The pre-deformed material’s...
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Comparison of Doppler Effect Estimation Methods for MFSK Transmission in Multipath Hydroacoustic Channel
PublikacjaUnderwater wireless communication remains a challenging topic, particularly for applications such as wreck penetration where multipath and Doppler effects are very intense. These effects are becoming even more difficult to mitigate for fast data transmission systems that utilize wideband signals. Due to the low propagation speed of acoustic wave in the water, there is a significant difference between the Doppler shift for lower...
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Collision-free network exploration
PublikacjaMobile agents start at different nodes of an n-node network. The agents synchronously move along the network edges in a collision-free way, i.e., in no round two agents may occupy the same node. An agent has no knowledge of the number and initial positions of other agents. We are looking for the shortest time required to reach a configuration in which each agent has visited all nodes and returned to its starting location. In...
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A proposition for integrating elements of game universe by means of behavioral trees
PublikacjaModern computer games often involve autonomous beings collaborating and competing with each other to reach their objectives in the game universe. It seems only natural to use agent-oriented approach in such cases. This article identifies the rules of building a game universe as an environment for executing agents. The paper also covers a method for decomposing compound behaviors into behavioral trees. Dividing complex behaviors...
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Analysis of the Ways to Identify Rail Running Surface Defects by Means of Vibration Signals
PublikacjaTh e article discusses a preliminary concept of a method enabling the identifi cation of chosen rail running surface defects, such as squats, spalling, and running surface defects, by analysing the parameters of vibration signals. It features a description of the methodology of the conducted tests, the scope thereof, and the selection of the measurement points with specifi c defect types. Th e article covers selected results of...
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Damage Analysis of Tensioning Cable Anchorage Zone of a Bridge Superstructure, Using CDP Abaqus Material Model
PublikacjaNumerical analysis of the tensioning cables anchorage zone of a bridge superstructure is presented in this paper. It aims to identify why severe concrete cracking occurs during the tensioning process in the vicinity of anchor heads. In order to simulate the tensioning, among others, a so-called local numerical model of a section of the bridge superstructure was created in the Abaqus Finite Element Method (FEM) environment. The...
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Maritime traffic situation awareness analysis via high-fidelity ship imaging trajectory
PublikacjaSituation awareness provides crucial yet instant information to maritime traffic participants, and significant attentions are paid to implement traffic situation awareness task via various maritime data source (e.g., automatic identification system, maritime surveillance video, radar, etc.). The study aims to analyze traffic situation with the support of ship imaging trajectory. First, we employ the dark channel prior model to...
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Deep Instance Segmentation of Laboratory Animals in Thermal Images
PublikacjaIn this paper we focus on the role of deep instance segmentation of laboratory rodents in thermal images. Thermal imaging is very suitable to observe the behaviour of laboratory animals, especially in low light conditions. It is an non-intrusive method allowing to monitor the activity of animals and potentially observe some physiological changes expressed in dynamic thermal patterns. The analysis of the recorded sequence of thermal...
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The experimental and numerical investigation of fracture behaviour in PMMA notched specimens under biaxial loading conditions – Tension with torsion
PublikacjaThis paper presents the results of experimental fracture test of flat PMMA specimens under biaxial loading condition tension with torsion (proportional). The specimens were made in two thicknesses: 5 and 15 mm and were weakened with V-type edge notches with different root radii: 0.5; 2 and 10 mm. Thanks to the ARAMIS 3D 4 M non-contact vision system, measurement of the elongation and twist angle were recorded. During experimental...
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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
PublikacjaThe 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...