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Wyniki wyszukiwania dla: BENDING CAPACITY
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Testing of low temperature behaviour of asphalt mixtures in bending creep test
PublikacjaThe paper presents a method of bending beam test and its importance for evaluation of asphalt mixtures behaviour at low temperatures. Two types of asphalt mixtures: asphalt concrete AC with normal paving grade bitumen and stone mastic asphalt SMA with SBS-modified bitumen were tested. Long-term oven ageing (LTOA) test was also used in the laboratory according to SHRP procedure. The Burgers model was applied and rheological parameters...
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Investigations on strength and fracture in RC beams scaled along height or length
PublikacjaThe objective of the present paper is to identify experimentally and theoretically differing failure mechanisms in reinforced concrete beams subjected to four-point bending for a separate variation of the depth and length at the constant thickness. Experiments were performed on reinforced concrete beams under four-point bending. Different failure mechanisms included steel yielding, diagonal tension or shear- compression depending...
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Bending of a Three-Layered Plate with Surface Stresses
PublikacjaWe discuss here the bending deformations of a three-layered plate taking into account surface and interfacial stresses. The first-order shear deformation plate theory and the Gurtin-Murdoch model of surface stresses will be considered and the formulae for stiffness parameters of the plate are derived. Their dependence on surface elastic moduli will be analyzed.
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NON-LOCAL VOLUMETRIC APPROACH TO ANALYSIS DEFECT'S SHAPE INFLUENCE ON SPECIMENS DURABILITY SUBJECTED TO BENDING AND TORSION
PublikacjaThe influence of defect features on fatigue behaviour is a complex trivial issue. Although the important advances over the last decades, the dialectical relationship between the defect orientation and durability is not clearly understood. The paper aims at studying the influence of the orientation of elliptical defects on the durability of samples made of C45 steel. Three types of samples with elliptical defects were subjected...
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Determination of the Bending Properties of Wire Rope Used in Cable Barrier Systems
PublikacjaThis paper presents research on the bending properties of 3 × 7 19-mm wire rope commonly used in road cable barriers. A total of 19 experimental tests were conducted. In addition, two nonlinear 3D numerical models of the wire rope using beam and solid finite elements were developed. Based on these models, four numerical simulations were carried out. The numerical results were validated against the experimental ones and a very good...
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FE investigations of the effect of fluctuating local tensile strength on coupled energetic-statistical size effect in concrete beams
PublikacjaThe effect of fluctuating local tensile strength on a coupled energetic-statistical size effect in plain concrete beams under bending was numerically investigated. First, the influence of varying autocorrelation length of the random field describing a spatial variation of local tensile strength was studied. Next, the influence of the coefficient of variation of local tensile strength was analyzed. The numerical FE investigations...
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Influence of mesh density on 2D viscous flutter in a turbomachinery cascade
PublikacjaIn this study numerical simulations of 2D viscous flutter were performed and compared with available experimental results for various mesh densities and flow parameters. Calculations were carried out for the bending oscillations of an Eleventh Standard Configuration cascade. ANSYS CFX code was used for the SST, SA and k-ω turbulence model calculations.
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Fatigue Bending of V-Notched Cold-Sprayed FeCoCrNiMn Coatings
PublikacjaCold-spray coatings were produced by FeCoCrNiMn high-entropy alloy powders deposited on carbon steel substrate. The coatings were realized at intermediate temperature and high pressure (at 1100 °C and 7 MPa). The coating microstructure was characterized by scanning electron microscopy and X-ray diffraction, revealing a very dense deposition and high flattening ratio of the splatted particles. This had a large influence on the...
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Simulations of Shear Zones and Cracks in Engineering Materials Using eXtended Finite Element Method
PublikacjaNumerical simulations of cracks and shear zones in quasi-brittle materials are presented. Extended Finite Element Method is used to describe both cracks and shear zones. In a description of tensile cracks, a Rankine criterion is assumed. A discrete Mohr-Coulomb law is adopted for simulations of shear zones. Results of simple numerical tests: unixial tension, bending and biaxial compression are demonstrated.
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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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Influence of Selected Warm Mix Asphalt Additives on Cracking Susceptibility of Asphalt Mixtures
PublikacjaWarm mix asphalt (WMA) has been widely accepted as a future asphalt paving technology. Besides clear advantages, there are still some concerns regarding durability and long-term performance of pavements made with this type of asphalt mixtures. One of the most important issues is low temperature behaviour of WMA because certain additives used for temperature reduction can aect bitumen properties. This paper presents the evaluation...
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The effect of external load on ultrasonic wave attenuation in steel bars under bending stresses
PublikacjaThe 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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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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A Diagnostic Method Based on Deflection Analysis for Monitoring Post-elastic Response of Beams
PublikacjaA non-destructive diagnostic method based on deflection analysis for monitoring the post-elastic response of beams was developed, and a diagnostic indicator was proposed. The indicator was defined as the second moment of the normalised curvature function about the mid-span, where the curvature was computed from the normalised deflection function. Elastic reference values of the indicator were computed for simply supported beams...
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The vibration-based assessment of the influence of elevated temperature on the condition of concrete beams with pultruded GFRP reinforcement
PublikacjaConcrete beams reinforced with glass fiber reinforced polymer (GFRP) bars subjected to elevated temperature have been experimentally studied. The influence of high temperatures on GFRP-reinforced concrete beams condition has been check both, destructively and nondestructively. The nondestructive tests foresaw vibration-based tests to obtain the natural frequency values after exposure to varying temperatures. The vibration-based...
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A new prototype of piezoelectric bending resonant transducer for analysis of soft tissues properties
PublikacjaThis paper is devoted to a new piezoelectric bending resonant transducer prototype dedicated to the characterization of the mechanical properties of soft tissue. A general description of the actuator’s structure is presented including the basic principles of the measurement. The chosen geometry of the prototype is discussed and compared with the existing version. Constitutive equations are presented for the active and passive layer...
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Effect of elliptical defect orientation on the durability of specimens subjected to cyclic bending
PublikacjaThis work presents the effect of elliptical defects orientation on the durability of specimens made of C45 steel. Three kinds of specimens with elliptical defects in the form of a one-sided notch oriented at different angles 45, 60, and 90 degrees were subjected to cyclic bending (R=-1). The stress state analysis was performed using local and non-local methods to determine an equivalent amplitude of stress, and then the results...
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Effect of bending-torsion on fracture and fatigue life for 18Ni300 steel specimens produced by SLM
PublikacjaIn this study, different fracture surfaces caused by fatigue failure were generated from 18Ni300 steel produced by selective laser melting (SLM). Hollow round bars with a transverse hole were tested under bending-torsion to investigate the crack initiation mechanisms and fatigue life. Next, the post-failure fracture surfaces were examined by optical profilometer and scanning electron microscope. The focus is placed on the relationship...
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Response to David Steigmann’s discussion of our paper
PublikacjaWe respond to David Steigmann's discussion of our paper "A general theory for anisotropic Kirchhoff-Love shells with in-plane bending of embedded fibers, Math. Mech. Solids, 28(5):1274-1317" (arXiv:2101.03122). His discussion allows us to clarify two misleading statements in our original paper, and confirm that its formulation is fully consistent with the formulation of Steigmann. We also demonstrate that some of our original statements...
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Local buckling and initial post-buckling behaviour of channel member flange - analytical approach
PublikacjaThe local buckling and initial post-buckling behaviour of the cold-formed channel member flange is investigated. The governing nonlinear differential equation for axially compressed columns and beams undergoing pure bending is derived using the stationary total potential energy principle. The critical stress and initial post-buckling equilibrium path is determined by means of a perturbation approach. The results obtained allow...
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The change of mechanical properties of selected wood species after drying process under various conditions
PublikacjaThe result of mechanical properties change of selected wood species after drying process under various parameters are presented. The global elasticity modulus and bending strength for steam dried, air-steam mixture dried and air dried samples as reference were measured. It allowed to reveal the effect of wood stream, air-steam mixture and their temperature on mechanical properties of wood. It has been recognized that steam and...
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Prediction of metal deformation due to line heating; an alternative method of mechanical bending, based on artificial neural network approach
PublikacjaLine heating is one of the alternative methods of forming metals and this kind of forming uses the heating torch as a source of heat input. During the process, many parameters are considered like the size of the substrate, thickness, cooling method, source power intensity, the travel speed of the power source, the sequence of heating, and so on. It is important to analyze the factors affecting the...
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Influence of Bitumen Type and Asphalt Mixture Composition on Low-Temperature Strength Properties According to Various Test Methods
PublikacjaIn regions with low-temperatures, action transverse cracks can appear in asphalt pavements as a result of thermal stresses that exceed the fracture strength of materials used in asphalt layers. To better understand thermal cracking phenomenon, strength properties of different asphalt mixtures were investigated. Four test methods were used to assess the influence of bitumen type and mixture composition on tensile strength properties...
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Mechanical and structural investigations of wings of selected insect species
PublikacjaThis paper presents research and measurements leading to obtaining the Young’s modulus of wing bearing structures of selected insect species. A small testing machine intended for three-point bending and equipped with instruments registering low forces was constructed for the needs of the experiment. The machine was used to perform numerous bending tests of wings of three species of insects (obtained from a breeding farm): Attacus...
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Fracture Surface Behavior of 34CrNiMo6 High-Strength Steel Bars with Blind Holes under Bending-Torsion Fatigue
PublikacjaThe present study evaluates the fracture surface response of fatigued 34CrNiMo6 steel bars with transverse blind holes subjected to bending with torsion loading. The analysis of the geometric product specification was performed by means of height parameters Sx, functional volume parameters Vx, and fractal dimension Df. Surface topography measurements were carried out using an optical profilometer with focus variation technology....
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Numerical simulation of asphalt mixtures fracture using continuum models
PublikacjaThe paper considers numerical models of fracture processes of semi-circular asphalt mixture specimens subjected to three-point bending. Parameter calibration of the asphalt mixture constitutive models requires advanced, complex experimental test procedures. The highly non-homogeneous material is numerically modelled by a quasicontinuum model. The computational parameters are averaged data of the components, i.e. asphalt, aggregate...
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Experimental and numerical study on stability loss of innovative geometry steel girder
PublikacjaThis paper presents the experimental and numerical analysis of an innovative plate girder geometry with variable web thicknesses. An idea proposed in this research is to increase the stability of the girder web by increasing its thickness in the compressed zone. This solution can replace commonly used longitudinal stiffeners which are designed to prevent web local loss of stability. Moreover, such an innovative approach requires...
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Comparative analysis of mechanical conditions in bone union following first metatarsophalangeal joint arthrodesis with varied locking plate positions: A finite element analysis
PublikacjaFirst metatarsophalangeal joint arthrodesis is a typical medical treatment performed in cases of arthritis or joint deformity. The gold standard for this procedure is arthrodesis stabilisation with the dorsally positioned plate. However, according to the authors’ previous studies, medially positioned plate provides greater bending stiffness. It is worth to compare the mechanical conditions for bone formation in the fracture callus...
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Assessment of Thermal Stresses in Asphalt Mixtures at Low Temperatures Using the Tensile Creep Test and the Bending Beam Creep Test
PublikacjaThermal stresses are leading factors that influence low-temperature cracking behavior of asphalt pavements. During winter, when the temperature drops to significantly low values, tensile thermal stresses develop as a result of pavement contraction. Creep test methods can be suitable for the assessment of low-temperature properties of asphalt mixtures. To evaluate the influence of creep test methods on the obtained low-temperature...
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Autogenous Fiber Laser Welding of 316L Austenitic and 2304 Lean Duplex Stainless Steels
PublikacjaThis study presents results of experimental tests on quality of dissimilar welded joints between 316L austenitic and 2304 lean duplex stainless steels, welded without ceramic backing. Fiber laser welded butt joints at a thickness of 8 mm were subjected to non‐destructive testing (visual and penetrant), destructive testing (static tensile test, bending test, and microhardness measurements) and structure observations (macro‐ and...
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The modyfication of the dynamic characteristics of vibratory conveyor
PublikacjaThe vibratory conveyors are used in the industry for continuous transportation of loose substances on distance up to 20meters. These conveyors are often suspended on expensive and massive frames, which are softly vibroisolated from the ground. As a result, they transfer significant dynamic forces on the ground. In case of 5 - 20 meter-long devices, the biggest construction problems are proper vibrations of the panel caused by bilateral...
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FEM simulation of laminate failure in the three point bending
PublikacjaThe paper presents a FEM simulation of failure of laminate subjected to the three point bending. The numeri-cal model is based on the equivalent single layer approach with 6-paramater non-linear shell theory kinematics. It is implemented in the non-commercial FEM code. The failure initiation is detected with the use of Tsai-Wu criterion. After the failure onset the progressive failure process is modelled through the appropriate...
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Asphalt concrete subjected to long-time loading at low temperatures – Deviations from the time-temperature superposition principle
PublikacjaThe article presents the observed deviations from the time-temperature superposition principle of asphalt concretes, tested in the bending beam creep test at low temperatures for a long time of loading. In almost all tested asphalt concretes, deviations appeared after 500 s of loading at the temperature of -10 C. Some types of bitumen presented deviations at other temperatures – usually the harder the grade of the bitumen, the...
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Numerical investigations on early indicators of fracture in concrete at meso-scale.
PublikacjaFracture is a major reason of the global failure of concretes. The understanding of fracture is important to ensure the safety of structures and to optimize the material behaviour. In particular an early prediction possibility of fracture in concretes is of major importance. In this paper, concrete fracture under bending was numerically analysed using the Discrete Element Method (DEM). The real mesoscopic structure of a concrete...
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On the durability of the hydraulic satellite motor working mechanism in overload condition
PublikacjaThe paper presents the newest construction of the hydraulic satellite pump/motor. In this study, the fracture of the hydraulic satellite motor working mechanism is investigated. Factors influencing the durability of satellite working mechanism have been described. The durability of the hydraulic satellite motor working mechanism at a load, corresponding to a pressure of 15 MPa supplied with refined rapeseed oil is very low. Analyses...
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Detection of debonding in reinforced concrete beams using ultrasonic transmission tomography and hybrid ray tracing technique
PublikacjaThis paper concerns inspection of reinforced concrete elements, with particular emphasis on assessing the quality of the adhesive connection between steel and concrete. A novel theoretical model was developed to determine the paths of transmitted, refracted and reflected elastic waves as well as a creeping wave propagated along the inclusion surface. Imaging the internal structure of tested beams was based on wave propagation measurements...
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The correlation of fractal dimension to fracture surface slope for fatigue crack initiation analysis under bending-torsion loading in high-strength steels
PublikacjaIn this study, the fractal dimension of fatigue fracture surfaces is investigated in order to find an alternative failure loading indicator. Some of many metrological factors are generalized by reducing the fracture surface structure to one factor and develop an entire fracture surface procedure by analyzing the impact of surface slope and calculation resolution. Three notched geometries are studied under cyclic bending-torsion:...
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Fracture simulations in concrete beam under bending using a mesoscopic model with cohesive elements
PublikacjaThe 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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Stability and limit load analysis of a cold-formed channel section column
PublikacjaThe paper presents stability and limit load analysis of a steel column 1440 mm high of a cold-formed channel section, subjected to a combination of compression and bending. Experimental results were compared to the resistance of a code procedure and to the outcome of numerical non-linear analysis. Comparison was made of numerical solutions by means of static (Riks) and dynamic (Explicit and Implicit) methods. Perfectly elastic...
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Ultrasound monitoring for evaluation of damage in reinforced concrete
PublikacjaThe paper deals with automated monitoring of damage evolution in concrete elements subjected to three-point bending tests. The monitoring is based on the nonlinear interactions of traveling ultrasonic waves with micro-crack zones inside the concrete specimens and surface-breaking cracks. The developed procedure assumes semi-continuous ultrasonic testing during the element full loading cycle and generation of the power spectral...
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Continuum models for pantographic blocks with second gradient energies which are incomplete
PublikacjaWe postulate a deformation energy for describing the mechanical behavior of so called pantographic blocks, that is bodies constituted by stacking of layers of pantographic sheets. We remark that the pantographic effect is limited in the plane of pantographic sheets and therefore only the second derivatives of transverse displacements along the pantographic fibers appear in the chosen deformation energy. We use this novel energy...
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Development and application of asphalt binder relaxation test in different dynamic shear rheometers
PublikacjaIn this study, a novel relaxation test is proposed to evaluate asphalt binder low temperature properties using a Dynamic Shear Rheometer (DSR) with parallel plates of 4 mm in diameter. Three rheometers from three different manufacturers are used to analyze seven asphalt binders. Different material parameters are derived which are useful to evaluate and discriminate different asphalt binders. Test results of all three instruments...
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On Anti-Plane Surface Waves Considering Highly Anisotropic Surface Elasticity Constitutive Relations
PublikacjaWithin the framework of highly anisotropic surface elasticity model we discuss the propagation of new type of surface waves that are anti-plane surface waves. By the highly anisotropic surface elasticity model we mean the model with a surface strain energy density which depends on incomplete set of second derivatives of displacements. From the physical point of view this model corresponds to a coating made of a family of parallel...
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On phase equilibrium of an elastic liquid shell with wedge disclination
PublikacjaBased on the six-parameter shell theory we consider the phase equilibrium of a two-phase liquid membrane containing a wedge disclination. The considered problems are related to modelling of phase transitions in biological or lipid membranes. In order to capture the membrane behaviour we consider a special case of elastic shells which energy is invariant under major transformations of a reference configuration and can be treated...
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Mechanical compatibility of implants used in hernia repair with abdominal wall
PublikacjaThe paper deals with a membrane model of a synthetic surgical mesh for treatment of abdominal hernia. The authors analyse the compatibility of two implant types with the human wall: Dualmesh Gore and Proceed. The finite element method is applied to simulate tjhe behavior of the proposed model. Due fact that recurrences are usually caused by connection failure, this study is focused on reaction forces in supports representing the...
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Failure characterisation of sandwich beams using integrated acoustic emission and digital image correlation techniques
PublikacjaThe paper presents the experimental study of the failure behaviour of sandwich beams subjected to bending. The samples examined are sandwich beams made of polyethylene terephthalate foam core and glass fibre-reinforced polymer laminate face sheets. In a series of experiments, it has been proposed to integrate diagnostic techniques with acoustic emission and digital image correlation to accurately track the cracking process on the...
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A comprehensive study on nonlinear hygro-thermo-mechanical analysis of thick functionally graded porous rotating disk based on two quasi three-dimensional theories
PublikacjaIn this paper, a highly efficient quasi three-dimensional theory has been used to study the nonlinear hygro-thermo-mechanical bending analysis of very thick functionally graded material (FGM) rotating disk in hygro-thermal environment considering the porosity as a structural defect. Two applied quasi three-dimensional displacement fields are assumed in which the strain along the thickness is not zero unlike most of the other plate...
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The energy approach to fatigue crack growth of S355 steel welded specimens subjected to bending
PublikacjaThe study presents the results of the research on the rate of fatigue crack growth subjected to bending in the ferritic-pearlitic structure. The studies were carried out at a constant amplitude of the moment and at various values of the load ratios R and at the operating frequency of the machine of 28.4 Hz. Flat specimens made of S355 steel and with fillet welds and with double-sided blunt external notches as well as concave...
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Notch fatigue analysis and life assessment using an energy field intensity approach in 7050-T6 aluminium alloy under bending-torsion loading
PublikacjaThis paper studies the fatigue crack initiation and fatigue crack propagation of notched cylindrical bars made of 7050-T6 aluminium alloy subjected to multiaxial bending-torsion loading. The sites of crack initiation and the angles of crack initiation were successfully predicted from the distribution of the first principal stress at the notch surface. Fatigue crack initiation lives were computed through the new concept of energy...
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SIMULATIONS OF FRACTURE IN CONCRETE BEAMS UNDER BENDING USING A CONTINUUM AND DISCRETE APPROACH
PublikacjaThe 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...