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Search results for: SURFACE PLASTIC DEFORMATION
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The influence of plastic deformation on the magnetoelastic properties of the CSN12021 grade steel
PublicationWłasności magnetosprężyste materiałów są silnie modyfikowane przez zmiany struktury dyslokacyjnej, które są wynikiem procesów deformacji plastycznej. Zmiany te mogą być wykorzystane jako podstawa do opracowania metody nieniszczącej oceny stopnia deformacji materiału.Jak dotychczas zaproponowane zostały różne metody, oparte na pomiarach pętli histerezy magnetycznej czy też natężenia magnetycznego efektu Barkhausena. Artykuł porównuje...
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Impact of plastic deformation on magnetoacoustic properties of Fe-2%Si alloy
PublicationW artykule przedstawiono wyniki komplementarnych badań własności magnetycznych stopu Fe-2%Si po deformacji plastycznej. Badania obejmowały pomiary pętli histerezy magnetycznej B(H), magnetycznego efektu Barkhausena oraz emisjii magnetoakustycznej. Badane próbki poddane były deformacji plastycznej do poziomu sięgajćego 8%. Właściwości pętli histerezy zostały skwantyfikowane z wykorzystaniem pola koercji oraz maksymalnej magnetycznej...
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A Non-local elasto-plastic model to describe localisations of deformation in concrete
PublicationPrzedstawiono wyniki numerycznej symulacji lokalizacji odkształceń stosując metodę elementów skończonych na bazie nielokalnego prawa sprężysto-plastycznego dla betonu. Prawo wykorzystuje długość charakterystyczną. Obliczenia dla ściskania jednoosiowego pokazały, że wyniki numeryczne nie zależą od siatki MES. Osiągnięto pełną regularyzację problemu brzegowego.
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Modelling tunnelling-induced deformation in stiff soils with a hyperelastic–plastic anisotropic model
PublicationIn this paper, the tunnelling-induced deformation in anisotropic stiff soils is analysed using FE modelling. The influence of material description is investigated rather than an advanced simulation of the tunnelling method. A new hyperelastic– plastic model is proposed to describe the anisotropic mechanical behaviour of stiff highly overconsolidated soil. This model can reproduce the superposition of variable stress-induced anisotropy...
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Possibility of Application of Magnetoacoustic Emission for the Assessment of Plastic Deformation Level in Ferrous Materials
PublicationArtykuł prezentuje wyniki badań dotyczących możliwości zastosowana emisji magnetoakustycznej (EMA) do nieniszczącej oceny stopnia deformacji plastycznej próbek poddanych jednoosiowemu rozciąganiu. Przebadane zostały cztery różne materiały: stale 13HMF, CSN12021 i P91 oraz żelazo Armco. Badania pokazały, że różne parametry magnetyczne i magnetoakustyczne badanych materiałów mogą zmieniać się w rożny sposób, jednakże zawsze obserwuje...
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Influence of plastic deformation on stray magnetic field distribution of soft magnetic steel sample
PublicationThe effect of various combinations of conditions, i.e., presence of the Earth’s magnetic field during and after deformation on the distribution of stray magnetic field of S355 steel sample, which is locally deformed, was investigated. Some of the stages of the experiment were carried out in zero magnetic field. Compensation of the Earth’s magnetic field was obtained by the application of a pair of Helmholtz coils. These coils are...
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Modeling of effect of plastic deformation on Barkhausen noise and magnetoacoustic emission in iron with 2% silicon
PublicationW modelowaniu zaadaptowano model Alessandro-Beatrice-Bertotti-Montorsi dla opisu ruchu granic nie-180 stopniowych oraz model Jiles-Atherton dla opisu wpływu plastycznej deformacji na natężenie efektu Barkhausena oraz emisji magnetoakustcznej.
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Evaluation of the impact of geometry and plastic deformation on the stray magnetic field around the bone shaped sample
PublicationInfluence of two factors: the variable cross-section and the localized plastic deformation, which affect the stray magnetic field profile of a ferromagnetic sample have been studied. Evaluation of an effect size is based on the analysis of the stray magnetic field component which is tangential to the longest dimension of a sample. However, in order to describe the nature of the stray magnetic field, the normal component (perpendicular...
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The Dominant Influence of Plastic Deformation Induced Residual Stress on the Barkhausen Effect Signal in Martensitic Steels
PublicationThe paper presents the results of investigation of the influence of plastic deformation on the magnetic properties of martensitic steel (P91 grade). The properties of the hysteresis loops as well as of the Barkhausen effect (BE) signal are analysed for both tensile and compressive loading up to ε = 10% of plastic deformation. The choice of the steel and of the deformation range is unique, since for such combination one can expect...
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Surface layer defects on injection-molded plastic components
PublicationProces wtryskiwania jakkolwiek jest powszechnie stosowany w przemyśle nie jest jeszcze do końca przebadany. W pracy przedstawiono model i symulację numeryczna procesu wtryskiwania wykonaną na bazie programu FIDAP. Na tej podstawie przedstawiono proces zachowania się tworzywa podczas procesu wtryskiwania w strefie przyściennej formy. Wyniki z symulacji porównano z danymi ekspermentalnymi.
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Multiparameter analysis of the Barkhausen noise signal and its application for the assessment of plastic deformation level in 13HMF grade steel
PublicationArtykuł przedstawia wyniki wieloparametrowej analizy właściwości sygnału szumu Barkhausena (BN). Poza powszechnie stosowanymi kwantyfikatorami sygnału szumu Barkhausena takimi jak amplituda, całka z obwiedni sygnału czy też wynikami analizy impulsowej sygnału proponujemy dodatkową analizę opartą na zmianach amplitudy prądu magnesującego. Jak się okazuje charakter zmian sygnału Barkhausena (w funkcji stopnia deformacji plastycznej)...
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Deformation and Surface Color Changes of Beech and Oak Wood Lamellas Resulting from the Drying Process
PublicationThe drying process was examined relative to parameters’ influence on the deformation and surface layer color changes of beech wood (Fagus sylvatica L.) and oak wood (Quercus robur L.). The goal was to analyze the impact of drying process conditions, wood and growth rings types, and load on the deformation and surface color changes of drying thin wooden elements. A further aim was to reduce the time of the lamella drying and minimize...
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An isogeometric finite element formulation for boundary and shell viscoelasticity based on a multiplicative surface deformation split
PublicationThis work presents a numerical formulation to model isotropic viscoelastic material behavior for membranes and thin shells. The surface and the shell theory are formulated within a curvilinear coordinate system,which allows the representation of general surfaces and deformations. The kinematics follow from Kirchhoff–Love theory and the discretization makes use of isogeometric shape functions. A multiplicative split of the surface...
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Behaviour of orthotropic surgical implant in hernia repair due to the material orientation and abdomen surface deformation
Publicationrelation to the different range of typical deformations observed in different directions and zones of abdomen surface due to the patients’ life activities, has a significant influence on the extreme junction forces in the mesh–tissue connections and hence the repair persistence. The finite element model of the orthotropic implant was developed, and the junction forces in the connections of tissue and mesh were studied. The kinematical...
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Yield surface identification of CP-Ti and its evolution reflecting pre-deformation under complex loading
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Investigation of abdomen surface deformation due to life excitation: implications for implant selection and orientation in laparoscopic ventral hernia repair
PublicationVentral hernia is a common medical problem. Statistically there are around 10% recurrences of the sickness. The authors' former investigation proved edges of the hernia orifice displacements to be one of the factors causing recurrence. Thus, experimental investigation of the abdomen surface deformation due to some normal activities of people is studied.The extreme strains, their localization and directions are identified. The acquired...
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On modelling and non-linear elasto-plastic analysis of thin shells with deformable junctions
PublicationThe undeformed base surface of the irregular thin shell is modelled by the union of a finite number of regular smooth surface elements joined together along spatial curvilinear surface edges. The equilibrium conditions are formulated by postulating an appropriate form of the principle of virtual work, where also deformability of shell junctions is taken into account. The PVW is then discretised by C1 finite elements and the incremental-iterative...
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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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Separation of the effects of notch and macro residual stress on the MFL signal characteristics
PublicationMagnetic flux leakage (MFL) distribution for three configurations of samples has been investigated in order to study the influence of notch and plastic deformation separately as well as together. Samples have been made of S355 steel. The MFL signal measurements were carried out along the longest dimension of the sample over a length of 120 mm. Two components of magnetic field were measured: 1) tangential to the main axis and 2)...
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Mechanical Behavior of Bi-Layer and Dispersion Coatings Composed of Several Nanostructures on Ti13Nb13Zr Alloy
PublicationTitanium implants are commonly used because of several advantages, but their surface modification is necessary to enhance bioactivity. Recently, their surface coatings were developed to induce local antibacterial properties. The aim of this research was to investigate and compare me-chanical properties of three coatings: multi-wall carbon nanotubes (MWCNTs), bi-layer composed of an inner MWCNTs layer and an outer TiO2 layer, and...
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Corrosion and Cavitation Resistances of Low Alloy Steel After Frictional-Mechanical Treatment
PublicationPaper presents the results of the studies of wear, corrosion and cavitation resistances of the S355J2 low alloy medium carbon steel subjected to surface modification by friction-mechanical treatment, as tested in sea water simulated solution. To evaluate the effect of the surface treatment, the comparative studies of the corrosive properties of the steel before and after treatment have been considered. The treatment due to a severe...
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Degradation of implantable materials – in vivo and in vitro research
PublicationThe article concerns the biological and electrochemical degradation of metallic implants in vivo and in vitro studies. The in vivo research dealt with degradation of plates used to join bones, as well as endoprostheses. The most common damages were: metalosis, breaking in the microstructure changes, breaking in area of holes, as well as plastic deformation throughout the length of an implant. The material used for the research...
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On the application of magnetoelastic properties measureme nts for plastic level determination in martensitic steels
PublicationThe change in the dislocation density, induced by plastic deformation, influences strongly the magnetic domain structure inside the material. Being so, classic parameters, like the coercivity or magnetic permeability, can be a good measure of the deformation level, yet their reliable determination in a non-destructive way in industrial environment is problematic. The magnetoacoustic emission (MAE) which results from the non-180...
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Influence of soil anisotropic stiffness on the deformation induced by an open pit excavation.
PublicationIn this paper, the problem of deformation induced by an open pit excavation in anisotropic stiff soils is analysed by FE modelling. The presented research is focused on the influence of material model with anisotropic stiffness on the accuracy of deformation predictions as compared with the field measurements. A new hyperelastic-plastic model is applied to simulate anisotropic mechanical behaviour of stiff soils. It is capable...
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On the plastic buckling of curved carbon nanotubes
PublicationThis research, for the first time, predicts theoretically static stability response of a curved carbon nanotube (CCNT) under an elastoplastic behavior with several boundary conditions. The CCNT is exposed to axial compressive loads. The equilibrium equations are extracted regarding the Euler–Bernoulli displacement field by means of the principle of minimizing total potential energy. The elastoplastic stress-strain is concerned...
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LCF behavior of 2024AA under uni- and biaxial loading taking into account creep pre-deformation
PublicationThis 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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Experimental study on the behaviour of steel columns under seismic-induced axial impact load
PublicationIt has been observed during major earthquakes that the so called soft-storey failure of an upper floor of a structure results in large impact load acting on structural members of the lower storeys. It may further lead to progressive collapse of the whole structure substantially intensifying human and material losses. Therefore, the aim of this paper is to investigate experimentally the behaviour of columns under bending (observed...
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Experimental investigations and damage growth modeling of EN‐AW 2024 aluminum alloy under LCF loading accounting creep pre‐deformation
PublicationThis article presents the results of experimental tests of creep rupture and of low-cycle fatigue (LCF) of EN-AW 2024 aluminum alloy devoid of damage and having preliminary damage. The preliminary damage was dealt in the process of creep at elevated temperature 100C, 200C, and 300C until achievement of two different strain values at each temperature. Samples with preliminary damage were subjected to fatigue tests at room temperature....
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Nanotechnologies in Development of Structural Materials and Biomaterials
PublicationThe nanometric materials and technologies resulted in nanostructures are reviewed. The examples of nanomaterials are shown. The typical nanotechnologies, including plastic deformation, mechanical attrition, controlled detonation, hot plasma jet synthesis, laser vaporisation, CVD and PVD, mechanical milling, annealing, ultrasonic irradiation, nanolithography, electrocrystallisation, electrospinning, sol-gel method, cryogenic laser-enhanced...
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Cavity-expansion approximation for projectile impact and penetration into sand
PublicationA one-dimensional problem of a spherical cavity expanding at a constant velocity from zero initial radius in an infinite granular medium, which has the first-kind self-similar solution, is considered. We are solving this dynamic spherical cavity-expansion problem to model rigid spheres penetrating into a granular media. Elastic–plastic deformation of the granular media is described in a barotropic approximation, using the high-pressure...
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Prediction of the Mechanical Properties of P91 Steel by Means of Magneto-acoustic Emission and Acoustic Birefringence
PublicationThe paper describes an application of nondestructive volumetric magnetic and ultrasonic techniques for evaluation of the selected mechanical parameter variations of P91 steel having direct influence on its suitability for further use in critical components used in power plants. Two different types of deformation processes were carried out. First, a series of the P91 steel specimens was subjected to creep and second, one to plastic...
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Behaviour of deformed steel columns exposed to impact load during earthquakes - experimental study
PublicationIt has been observed during major earthquakes that the so called soft-storey failure of an upper floor of a structure results in large impact load acting on structural members of the lower storeys. It may further lead to progressive collapse of the whole structure substantially intensifying human and material losses. The aim of this paper is to investigate experimentally the behaviour of horizontally deformed columns (deformation...
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Experimental and numerical study on deformed steel columns subjected to impact load during earthquakes
PublicationThe soft-storey failure is one of the most typical types of damage observed in buildings during earthquakes. The failure of an upper soft storey of a structure results in large impact load acting on the lower floors and if the resistance of the structural members of the lower storeys is not sufficient it may further lead to progressive collapse of the whole building. The aim of the present paper is to investigate the dynamic behaviour...
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"Raport z wstępnych badań własności stali trudnościeralnej 460HB",. ang "Report on preliminary tests of the properties of wear-resistant steel 460HB"
PublicationMikrostrukturę badanej stali trudnościeralnej 460HB stanowi drobnoziarnisty martenzyt odpuszczony, który jest właściwy dla stali konstrukcyjnych niskowęglowych, niskostopowych ulepszonych cieplnie. W przypadku blach grubych, do których zalicza się badana stal, struktura może ulec zaburzeniu, jeżeli w hutniczym procesie wytwórczym wystąpiła niejednorodność odkształcenia plastycznego i w konsekwencji tworzenie się pasm segregacyjnych,...
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The experimental and numerical investigation of fracture behaviour in PMMA notched specimens under biaxial loading conditions – Tension with torsion
PublicationThis 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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Propagation of acoustic pulses in some fluids with yield stress
PublicationThis study is devoted to the derivation of approximate equations governing acoustic pulses in flows with yieldstress, including some time-dependent flows with a slow dependence on time of yield stress and apparent viscosity. Themodeling of yield stress and apparent viscosity in the vicinity of a zero deformation rate allows us to consider a thixotropicfluid as a Bingham plastic with coefficients that are dependent on time. The...
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LDFEM analysis of FDP auger installation in cohesive soil
PublicationThis paper deals with large deformation finite element (LDFE) preliminary modelling of Full Displacement Pile (FDP) installation in cohesive soil deposit located in Jazowa, Poland. The detailed FDP auger geometry is applied and the drilling process is modelled with full 3D Coupled Eulerian-Lagrangian (CEL) formulation. The total stress approach and elastic-perfectly plastic model with rate-dependent Mises plasticity is used. The...
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Przepustowość przepustu niezatopionego
PublicationPodczas przepływu w warunkach niezatopionego wlotu i wylotu w przewodzie przepustu woda tworzyć będzie swobodne zwierciadło. Przepływ bezciśnieniowy w przewodzie przepustu może wystąpić również w warunkach zatopionego wlotu. W pracy porównano wyniki obliczeń przepustowości całego przepustu i samego przewodu o przekroju kołowym i kwadratowym. W warunkach spokojnego ruchu wody, przy braku spiętrzenia na wylocie, o przepustowości...
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Medially positioned plate in first metatarsophalangeal joint arthrodesis
PublicationObjective The purpose of this study was to biomechanically compare the stability of first metatarsophalangeal (MTP1) joint arthrodesis with dorsally and medially positioned plates. Methods A physical model of the MTP1 joint consists of printed synthetic bones, a titanium locking plate and screws. In the experiments, samples with dorsally and medially positioned plates were subjected to loading of ground load character in a universal...
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Investigation of the 0.4C-35Cr-45Ni-Nb Alloy after Service in High-Temperature Steam and Hydrocarbons Environment
PublicationThe paper presents the results of investigation of the 0.4C-35Cr-45Ni-Nb alloy, which operated in the cracked hydrocarbon feeds and dilution steam at 1125 C. The material originated from the pyrolytic furnace coil tubes, of which internal walls were in contact with the aforementioned medium, whereas the external walls were in contact with the flue gases. The examination included metallographic and mechanical tests on the material...
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Characteristics of silver-dopped carbon nanotube coating destined for medical applications
PublicationCarbon nanotubes are materials demonstrating outstanding mechanical, chemical, and physical properties and are considered coatings of titanium implants. The present research is aimed to characterize the microstructure and properties of the multi-wall carbon nanotubes (MWCNTs) layer decorated with silver nanoparticles (Ag NPs) on the Ti13Nb13Zr alloy destined for long-term implants. The electrophoretic deposition of coatings...
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A facile structural manipulation strategy to prepare ultra-strong, super-tough, and thermally stable polylactide/nucleating agent composites
PublicationPolylactide (PLA) is a biodegradable thermoplastic widely used in diferent felds, but it should be adequately modifed considering high-performance applications. However, the current processes for developing PLA materials achieve high strength at the expense of toughness or ductility of the materials. Therefore, there is need to develop new strategies for generation of PLA materials with high strength, great toughness, good ductility,...
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Effect of Base-Connection Strength and Ductility on the Seismic Performance of Steel Moment-Resisting Frames
PublicationColumn-base connections in steel moment-resisting frames (SMFs) in seismic regions are commonly designed to develop the capacity of adjoining column with an intent to develop a plastic hinge in the column member, rather than in the connection (i.e., a strong-base design). Recent research has shown base connections to possess high ductility, indicating that this practice may be not only expensive but also unnecessary. This suggests...
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THE STUDY OF WATER POLLUTION OF THE LOWER VISTULA RIVER BY PLASTIC PARTICLES
PublicationSince the beginning of widespread use of plastic its consumption and production has been constantly increasing. As a result of human activity part of waste ends up in our environment and is deposited in each of the elements of the biosphere. These impurities can be in the form of large elements, small particles fragmented to macroscopic level (pellets, facial scrub grains) and the microparticles visible under a microscope. Particularly...
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The Influence of Shear Deformation in analysis of plane frames
PublicationThe focus of the paper is to investigate the influence of shear deformation effect on the distribution of internal forces and frame deformation. To estimate shear deformation effect, the Timoshenko beam theory and the concept of shear deformation coefficients are used. Analysis of example frames gives the possibility to evaluate what have the most impact on size of shear deformation and in which type of frames the shear deformation...
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Study on some of the strength properties of soft clay stabilized with plastic waste strips
PublicationIt is well known that if plastic wastes are not well managed, it has a negative impact on the environment as well as on human health. In this study, recycling plastic waste in form of strips for stabilizing weak subgrade soil is proposed. For this purpose, a weak clay soil sample was mixed with 0.2%, 0.3%, and 0.4% of plastic strips by weight of soil, and the experimental results were compared to the control soil sample with 0%...
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Acoustic heating produced in the thermoviscous flow of a Bingham plastic
PublicationThis study is devoted to the instantaneous acoustic heating of a Bingham plastic. The model of the Bingham plastic's viscous stress tensor includes the yield stress along with the shear viscosity, which differentiates a Bingham plastic from a viscous Newtonian fluid. A special linear combination of the conservation equations in differential form makes it possible to reduce all acoustic terms in the linear part of of the final equation...
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Acoustic heating produced in the thermoviscous flow of a bingham plastic
PublicationThis study is devoted to the instantaneous acoustic heating of a Bingham plastic. The model of the Bingham plastic's viscous stress tensor includes the yield stress along with the shear viscosity, which differentiates a Bingham plastic from a viscous Newtonian fluid. A special linear combination of the conservation equations in differential form makes it possible to reduce all acoustic terms in the linear part of of the final equation...
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On Surface Kinetic Constitutive Relations
PublicationIn the framework of the strain gradient surface elasticity we discuss a consistent form of surface kinetic energy. This kinetic constitutive equation completes the statement of initial–boundary value problems. The proposed surface kinetic energy density is the most general function consistent with the constitutive relations in bulk. As the surface strain energy depends on the surface deformation gradient and its gradient, the kinetic...
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generation of the vorticity mode by sound in a bingham plastic
PublicationThis study investigates interaction between acoustic and non-acoustic modes, such as vorticity mode,in some class of a non-newtonian fluid called Bingham plastic. The instantaneous equations describinginteraction between different modes are derived. The attention is paid to the nonlinear effects in the fieldof intense sound. The resulting equations which describe dynamics of both sound and the vorticity modeapply to both periodic...