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Wyniki wyszukiwania dla: FRACTURE MECHACICS
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Strain sequence effect on fatigue life and fracture surface topography of 7075-T651 aluminium alloy
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Comparison of the fracture toughness of pine wood determined on the basis of orthogonal linear cutting and frame sawing
PublikacjaIn this paper, the values of the fracture toughness of Scots pine determined by cutting tests are presented. The cutting tests were carried out using the samples of Scotch pine (Pinus sylvestris L.) from Pomeranian Region, Poland. These experiments were carried out on two research stands: orthogonal linear cutting tests were conducted using the microtome instrument and the frame saw PRW-15M was used for sawing tests. The values...
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Fracture Areas Quantitative Investigating of Bending-Torsion Fatigued Low-Alloy High-Strength Steel
PublikacjaIn this study, the impact of pseudo-random non-proportional bending-torsion fatigue loadings proportion on the fatigue life and the fracture surface topography was analyzed. Investigation was carried out for 24 specimens made of S355J2 steel with 11 different ratios of maximum stresses λ. For these cases, after the fatigue tests, the surface topography measurements were carried out using an optical profilometer, using the focus...
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Strain sequence effect on fatigue life and fracture surface topography of 7075-T651 aluminium alloy
PublikacjaThe paper studies the effect of strain-loading sequence on fatigue lifetime and fracture surface topographies in 7075-T651 aluminum alloy specimens. Fatigue tests were performed in two ways: (i) constant-amplitude loading and (ii) two series of variable amplitude loading with non-zero mean strain values. The topography of the fatigue fractures was measured over their entire surfaces with the help of an optical confocal measurement...
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Cyclic deformation and fracture behaviour of additive manufactured maraging steel under variable-amplitude loading
PublikacjaThe cyclic deformation and fracture behaviour of 18Ni300 maraging steel produced by laser beam powder bed fusion is studied under variable-amplitude loading. The tests were conducted under fully-reversed strain-controlled conditions with a loading sequence comprising three ascending cycles and three descending cycles repeated sequentially until failure. After the tests, fracture surfaces were examined using height and volume surface...
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Fracture Surface Topography Parameters for S235JR Steel Adhesive Joints After Fatigue Shear Testing
PublikacjaThis paper presents the experimental results of a study investigating the effect of holes and notches made on the overlap ends on the strength of adhesive joints. Single-lap joints made of S235JR steel sheets bonded with Araldite 2024-2 epoxy adhesive were tested. For comparative reasons, static shear strength tests and high-cycle fatigue strength tests were performed. Adhesive-filled joints having three holes, each with a diameter...
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Fracture evolution in concrete compressive fatigue experiments based on X-ray micro-CT images
PublikacjaArtykuł omawia ewolucje pękania w betonie podczas cyklicznego ściskania betonu. Przestrzenną ewolucję pękania zobrazowano stosując mikro-tomograf rentgenowski. Zdjęcia wykonano dla różnych cykli zmęczeniowych. Wyniki porównano z testami monotonicznymi. Jakościowa ewolucja objętości pękania ze wzrostem zmęczeniowego zniszczenia pokazała silnie nieliniowy kształt.
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Experimental Investigations of Fracture Process Using DIC in Plain and Reinforced Concrete Beams under Bending
PublikacjaThe fracture behaviour of concrete and reinforced concrete beams under quasi-static three-point bending was comprehensively investigated with experiments at laboratory scale. The eight various concrete mixes were tested. The influence of the shape, volume and size of aggregate particles and reinforcement on concrete fracture under bending was studied. Displacements on the surface of concrete beams were measured by means of the...
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Comparative DEM calculations of fracture process in concrete considering real angular and artificial spherical aggregates
PublikacjaArtykuł omawia wyniki obliczeń numerycznych pękania dla betonu stosując metodę elementów dyskretnych (DEM). Beton był opisany jako materiał 4-fazowy i był poddany zginaniu. Zbadano wpływ kształtu kruszywa na proces pekania i na zalezność obciązenia od ugięcia. Wyniki dwuwymiarowe i trzywymiarowe porównano bezpośrednio z doświadczeniami. Wyniki pokazały duzy wpływ kształtu kruszywa na wyniki numeryczne.
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Advances in Applied Mechanics
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Journal of Geometric Mechanics
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Coupled Systems Mechanics
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Computational Particle Mechanics
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INTERNATIONAL APPLIED MECHANICS
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Extreme Mechanics Letters
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Journal of Solid Mechanics
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Engineering Solid Mechanics
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PNRPU Mechanics Bulletin
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Theoretical and Applied Mechanics
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Materials Physics and Mechanics
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Rock and Soil Mechanics
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Applied and Computational Mechanics
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International Journal of Mechanics
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PROBABILISTIC ENGINEERING MECHANICS
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Applied Mechanics Reviews
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Computational Continuum Mechanics
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Communications in Analysis and Mechanics
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Applied Mathematics and Mechanics
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STRUCTURAL ENGINEERING AND MECHANICS
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Thermal Buckling Analysis of Circular Bilayer Graphene sheets Resting on an Elastic Matrix Based on Nonlocal Continuum Mechanics
PublikacjaIn this article, the thermal buckling behavior of orthotropic circular bilayer graphene sheets embedded in the Winkler–Pasternak elastic medium is scrutinized. Using the nonlocal elasticity theory, the bilayer graphene sheets are modeled as a nonlocal double–layered plate that contains small scale effects and van der Waals (vdW) interaction forces. The vdW interaction forces between the layers are simulated as a set of linear springs...
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A Mesh Deformation Technique Based on Solid Mechanics for Parametric Analysis of High-Frequency Devices With 3-D FEM
PublikacjaIn this paper, a versatile technique for mesh defor- mation is discussed, targeted at the electromagnetic (EM) field simulation of high-frequency devices using the 3-D finite element method (FEM). The approach proposed applies a linear elasticity model to compute the displacements of the internal mesh nodes in 3-D when the structure geometry is changed. The technique is compared with an alternative approach...
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A new hyperbolic-polynomial higher-order elasticity theory for mechanics of thick FGM beams with imperfection in the material composition
PublikacjaA drawback to the material composition of thick functionally graded materials (FGM) beams is checked out in this research in conjunction with a novel hyperbolic‐polynomial higher‐order elasticity beam theory (HPET). The proposed beam model consists of a novel shape function for the distribution of shear stress deformation in the transverse coordinate. The beam theory also incorporates the stretching effect to present an indirect...
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The Use of 3D Titanium Miniplates in Surgical Treatment of Patients with Condylar Fractures
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Analysis of Factors Affecting Quality of Life in Patients Treated for Maxillofacial Fractures
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The use of the transparotid approach for surgical treatment of condylar fractures – Own experience
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Examining Feature Vector for Phoneme Recognition
PublikacjaThe aim of this paper is to analyze usability of descriptors coming from music information retrieval to the phoneme analysis. The case study presented consists in several steps. First, a short overview of parameters utilized in speech analysis is given. Then, a set of time and frequency domain-based parameters is selected and discussed in the context of stop consonant acoustical characteristics. A toolbox created for this purpose...
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An Approach to RBF Initialization with Feature Selection
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Application of discriminant analysis to feature extraction.
PublikacjaPierwotnie uzyskiwane wektory cech są wysokowymiarowe. Redukcja wymiarowości jest często osiągana poprzez transformacje przestrzeni cech. Niniejsza praca prezentuje uogólnione kryterium Fishera i jego podstawowe własności, dyskutowana jest także możliwość wyprowadzania i oceny heurystycznych metod ekstrakcji cech. Przedstawiono również nowy sekwencyjny algorytm selekcji cech dyskryminacyjnych.
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Automatic feature extraction for linear systems.
PublikacjaPraca przedstawia eksperymenty pokazujące istnienie uniwersalnego ekstraktora cech dla ograniczonego obszaru w przestrzeni parametrów systemu liniowego. System liniowy pobudzony był szumem o rozkładzie normalnym na wejściu. Zastosowano ewolucyjne metody poszukiwania ekstraktora w oparciu o jakość klasyfikacji sygnałów w dziedzinie cech wydobytych przez ekstraktor.
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Prediction of fracture toughness in fibre-reinforced concrete, mortar, and rocks using various Machine learning techniques
PublikacjaMachine Learning (ML) method is widely used in engineering applications such as fracture mechanics. In this study, twenty different ML algorithms were employed and compared for the prediction of the fracture toughness and fracture load in modes I, II, and mixed-mode (I-II) of various materials, including fibre-reinforced concrete, cement mortar, sandstone, white travertine, marble, and granite. A set of 401 specimens of “Brazilian...
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Influence of energy absorbers on Malgaigne fracture mechanism in lumbar-pelvic system under vertical impact load
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Brittle fracture of 100-, 110-, 111-oriented Cu crystals: MD vs. TB/MD approach
PublikacjaPrzeprowadzono wieloskalowe symulacje nanoindentacji miedzi nieskończenie twardym narzędziem, przy zastosowaniu metody dynamiki molekularnej, z siłami liczonymi na bieżąco w formalizmie ciasnego wiązania (TB). Przedstawiono wyniki dla trzech orientacji krystalicznych podłoża. Badano efekt dołączenia obliczeń TB na siłę normalną odczuwaną przez narzędzie i na przemieszczenia atomów podłoża, przez porównywanie z symulacją czystą...
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Formation and Growth of the Crack in Bonded Joints Under Mode I Fracture: Substrate Deflection at Crack Vicinity
PublikacjaAdhesive bonding is now commonly used in aircraft, cars, boats, etc. In these applications, thin panels are often bonded. In such thin structures, heterogeneous mechanical loading along the bondline edge (or potential crack front), is likely to arise due to 3D structural effects. The crack front and its vicinity is a special region, in that it is where structural properties of the adherend material meet those of the adhesive (discontinuity)....
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Characterization of fracture process in polyolefin fibre-reinforced concrete using ultrasonic waves and digital image correlation
PublikacjaThis study explores the monitoring of the fracture process in concrete beams and aims to characterize the evolution of damage in polyolefin fibre-reinforced concrete beams by utilizing the integrated application of two measurement techniques, digital image correlation and ultrasonic testing. The interpretation of registered wave time histories data was provided by the calculation of the magnitude-phase-composite metrics. An efficient...
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Correlation between Fractal Dimension and Areal Surface Parameters for Fracture Analysis after Bending-Torsion Fatigue
PublikacjaThis paper investigates the fracture surface topography of two steel and aluminum alloys subject to bending-torsion fatigue loadings, as well as their susceptibility to fatigue performance and failure mechanisms. Using fracture surface topography data analysis, elements with different geometries were elaborated. A correlation between the fractal dimension, other selected parameters of surface topography such as areal Sx, and...
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The use of a two-phase Monte Carlo material model to reflect the dispersion of asphalt concrete fracture parameters
PublikacjaThe work covers comprehensive laboratory tests of semi-circular bending (SCB) of asphalt concrete samples. The results of two test series, including four and 32 SCB specimens, indicate a substantial scatter of force–deflection (F-d) histories. The numerical analysis is aimed to reflect the maximum breaking load and fracture energy of the samples, pointing out their random character. The original simulation-based fictitious Monte...
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Fatigue fracture surface metrology of thin-walled tubular austenitic steel specimens after asynchronous loadings
PublikacjaThis paper aims to study the effect of asynchronous axial-torsional strain-controlled loading histories on fracture surface behavior of thin-walled tubular X5CrNi18-10 (304/304L) austenitic steel specimens. Tests under pure axial loading and pure torsional loading are also conducted to better segregate the effect of multiaxiality. The fractures surface topographies were examined through the profiles over the entire surface with...
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Topography measurement methods evaluation for entire bending-fatigued fracture surfaces of specimens obtained by explosive welding
PublikacjaIn 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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Orientation effects on the fracture behaviour of additively manufactured stainless steel 316L subjected to high cyclic fatigue
PublikacjaIn this paper, stainless steel 316L (SS316L) bars were additively manufactured (AM) in three orientations (Z – vertical, XY – horizontal, ZX45 – midway between vertical and horizontal) by using the Laser Powder Bed Fusion Melting (LPBF-M) method. The AM specimens were subjected to load control fatigue testing under full tension and compression (R = -1) at stress amplitudes ±350, ±400 and ±450 MPa. The XY and ZX45 printing orientations...
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The fracture behaviour of notched PMMA specimens under simple loading conditions – Tension and torsion experimental tests
PublikacjaThis paper presents the results of experimental testing of flat PMMA specimens during uniaxial loading conditions. Two separate tests were conducted: tensile and torsion. The specimens were weakened with V-type edge notches with different root radii: 0.5; 2 and 10 mm. The specimens were made in two thickness variants: 5 and 15 mm. Monotonic tensile and torsion tests were carried out while keeping the averaged strain rate constant,...