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Wyniki wyszukiwania dla: surface elasticity'surface waves
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Strongly anisotropic surface elasticity and antiplane surface waves
PublikacjaWithin the new model of surface elasticity, the propagation of anti-plane surface waves is discussed. For the proposed model, the surface strain energy depends on surface stretching and on changing of curvature along a preferred direction. From the continuum mechanics point of view, the model describes finite deformations of an elastic solid with an elastic membrane attached on its boundary reinforced by a family of aligned elastic...
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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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Transverse surface waves on a cylindrical surface with coating
PublikacjaWe discuss the propagation of transverse surface waves that are so-called whispering-gallery waves along a surface of an elastic cylinder with coating. The coating is modelled in the framework of linearized Gurtin–Murdoch surface elasticity. Other interpretations of the surface shear modulus are given and relations to so-called stiff interface and stiff skin model are discussed. The dispersion relations are obtained and analyzed.
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Surface finite viscoelasticity and surface anti-plane waves
PublikacjaWe introduce the surface viscoelasticity under finite deformations. The theory is straightforward generalization of the Gurtin–Murdoch model to materials with fading memory. Surface viscoelasticity may reflect some surface related creep/stress relaxation phenomena observed at small scales. Discussed model could also describe thin inelastic coatings or thin interfacial layers. The constitutive equations for surface stresses are...
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Surface and interfacial anti-plane waves in micropolar solids with surface energy
PublikacjaIn this work, the propagation behaviour of a surface wave in a micropolar elastic half-space with surface strain and kinetic energies localized at the surface and the propagation behaviour of an interfacial anti-plane wave between two micropolar elastic half-spaces with interfacial strain and kinetic energies localized at the interface have been studied. The Gurtin–Murdoch model has been adopted for surface and interfacial elasticity....
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Anti-plane surface waves in media with surface structure: Discrete vs. continuum model
PublikacjaWe present a comparison of the dispersion relations derived for anti-plane surface waves using the two distinct approaches of the surface elasticity vis-a-vis the lattice dynamics. We consider an elastic half-space with surface stresses described within the Gurtin–Murdoch model, and present a formulation of its discrete counterpart that is a square lattice half-plane with surface row of particles having mass and elastic bonds different...
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Comparison of anti-plane surface waves in strain-gradient materials and materials with surface stresses
PublikacjaHere we discuss the similarities and differences in anti-plane surface wave propagation in an elastic half-space within the framework of the theories of Gurtin–Murdoch surface elasticity and Toupin–Mindlin strain-gradient elasticity. The qualitative behaviour of the dispersion curves and the decay of the obtained solutions are quite similar. On the other hand, we show that the solutions relating to the surface elasticity model...
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On the Equations of the Surface Elasticity Model Based on the Theory of Polymeric Brushes
PublikacjaMotivating by theory of polymers, in particular, by the models of polymeric brushes we present here the homogenized (continual) two-dimensional (2D) model of surface elasticity. A polymeric brush consists of an system of almost aligned rigid polymeric chains. The interaction between chain links are described through Stockmayer potential, which take into account also dipole-dipole interactions. The presented 2D model can be treated...
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On Dynamic Boundary Conditions Within the Linear Steigmann-Ogden Model of Surface Elasticity and Strain Gradient Elasticity
PublikacjaWithin the strain gradient elasticity we discuss the dynamic boundary conditions taking into account surface stresses described by the Steigmann–Ogden model. The variational approach is applied with the use of the least action functional. The functional is represented as a sum of surface and volume integrals. The surface strain and kinetic energy densities are introduced. The Toupin–Mindlin formulation of the strain gradient elasticity...
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On the influence of a surface roughness on propagation of anti-plane short-length localized waves in a medium with surface coating
PublikacjaWe discuss the propagation of localized surface waves in the framework of the linear Gurtin–Murdoch surface elasticity and taking into account a roughness of a free boundary. We derive a boundary-value problem for anti-plane motions with curvilinear boundary and surface stresses. Using the asymptotic technique developed earlier, we obtain the form of a localized wave and analyze its amplitude evolution. As the main result we present...
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Anti-plane waves in an elastic thin strip with surface energy
PublikacjaWe consider anti-plane motions of an elastic plate taking into account surface energy within the linear Gurtin–Murdoch surface elasticity. Two boundary-value problems are considered that describe complete shear dynamics of a plate with free faces or with free and clamped faces, respectively. These problems correspond to anti-plane dynamics of an elastic film perfectly or non-perfectly attached to a rigid substrate. Detailed analysis...
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Automated non destructive testing by non-contact surface waves
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On Effective Bending Stiffness of a Laminate Nanoplate Considering Steigmann–Ogden Surface Elasticity
PublikacjaAs at the nanoscale the surface-to-volume ratio may be comparable with any characteristic length, while the material properties may essentially depend on surface/interface energy properties. In order to get effective material properties at the nanoscale, one can use various generalized models of continuum. In particular, within the framework of continuum mechanics, the surface elasticity is applied to the modelling of surface-related...
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On weak solutions of boundary value problems within the surface elasticity of Nth order
PublikacjaA study of existence and uniqueness of weak solutions to boundary value problems describing an elastic body with weakly nonlocal surface elasticity is presented. The chosen model incorporates the surface strain energy as a quadratic function of the surface strain tensor and the surface deformation gradients up to Nth order. The virtual work principle, extended for higher‐order strain gradient media, serves as a basis for defining...
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On the peculiarities of anti-plane surface waves propagation for media with microstructured coating
PublikacjaWe discuss new type of surface waves which exist in elastic media with surface energy. Here we present the model of a coating made of polymeric brush. From the physical point of view the considered model of surface elasticity describes a highly anisotropic surface coating. Here the surface energy model could be treated as 2D reduced strain gradient continuum as surface strain energy depends on few second spatial derivatives of...
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Accuracy of parameter identification using the dispersion of surface waves and the role of data quality for inhomogeneous concrete
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Anti-plane shear waves in an elastic strip rigidly attached to an elastic half-space
PublikacjaWe consider the anti-plane shear waves in a domain consisting of an infinite layer with a thin coating lying on an elastic half-space. The elastic properties of the coating, layer, and half-space are assumed to be different. On the free upper surface we assume the compatibility condition within the Gurtin–Murdoch surface elasticity, whereas at the plane interface we consider perfect contact. For this problem there exist two possible...
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On effective surface elastic moduli for microstructured strongly anisotropic coatings
PublikacjaThe determination of surface elastic moduli is discussed in the context of a recently proposed strongly anisotropic surface elasticity model. The aim of the model was to describe deformations of solids with thin elastic coatings associated with so-called hyperbolic metasurfaces. These metasurfaces can exhibit a quite unusual behaviour and concurrently a very promising wave propagation behaviour. In the model of strongly anisotropic...
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Effects of interfacial sliding on anti-plane waves in an elastic plate imperfectly attached to an elastic half-space
PublikacjaWe study the anti-plane shear waves in a domain consisting of an elastic layer (plate) with a coating attached to an elastic half-space (substrate). We assume an imperfect contact between the layer and the half-space, allowing some sliding. We also assume some elastic bonds between the layer and the substrate. On the free top surface we apply the compatibility conditions within the Gurtin–Murdoch surface elasticity. We found two...
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On nonlinear dilatational strain gradient elasticity
PublikacjaWe call nonlinear dilatational strain gradient elasticity the theory in which the specific class of dilatational second gradient continua is considered: those whose deformation energy depends, in an objective way, on the gradient of placement and on the gradient of the determinant of the gradient of placement. It is an interesting particular case of complete Toupin–Mindlin nonlinear strain gradient elasticity: indeed, in it, the...
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Modeling of free vibrations and resonant frequencies of simply-supported submerged horizontal plate
PublikacjaA theoretical approach was applied to study the vibration of simple-supported submerged horizontal plate. The derived analytical solution was used to determine natural frequencies for a horizontal plate vibrating in fluid. The investigations were conducted for a very wide range of material density and elasticity modulus covering all materials used in engineering practice. Analysis shows that plate vibration frequency decreases...
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Stateczność i niezawodność pełnomorskich platform wiertniczych
PublikacjaW pracy przedstawiono wieloletnie doświadczenia Autora w zakresie wybranych aspektów numerycznej analizy pełnomorskich platform wiertniczych, w szczególności stacjonarnych platform stalowych poddanych działaniu fal wiatrowych i wiatru. W opisie zachowania się platform uwzględniono współoddziaływanie trzech ośrodków: materiału konstrukcji, morskich fal wiatrowych i podłoża gruntowego. Przyjęcie do opisu stochastycznych właściwości...
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ANALIZA NUMERYCZNA WPŁYWU POZIOMU MORZA NA PRZEBIEG WEZBRAŃ W NADMORSKICH CIEKACH POWIERZCHNIOWYCH NA PRZYKŁADZIE POTOKU STRZYŻA W GDAŃSKU
PublikacjaW dzisiejszych czasach coraz większym problemem stają się podtopienia na terenach zurbanizowanych. Biorąc to pod uwagę, należy większą wagę przyłożyć do prawidłowego obliczania przepustowości koryta. Jednym z czynników wpływających na nie są warunki na odpływie. W przypadku potoków nadmorskich zależą one ściśle od poziomu morza. W pracy podjęto próbę wyznaczenia wpływu poziomu morza na przebieg wezbrań w nadmorskich ciekach powierzchniowych....
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APPLIED SURFACE SCIENCE
Czasopisma -
Jacek Ryl dr hab. inż.
OsobyStopień doktora nauk technicznych uzyskał w roku 2010. W tym samym roku podjął pracę w Katedrze Elektrochemii, Korozji i Inżynierii Materiałowej na Wydziale Chemicznym. W 2018 roku uzyskał stopień doktora habilitowanego nauk technicznych w dyscyplinie technologia chemiczna. Od 2021 roku zatrudniony w Instytucie Nanotechnologii i Inżynierii Materiałowej Wydziału Fizyki Technicznej i Matematyki Stosowanej PG. W pracy naukowej skupia...
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Surface Science - 2021/2022
Kursy OnlineThe goal of the subject is the presentation of basic problems resulting from he existence of interfacebetween material objects and its surroundings. Discussion of the consequences arising from the existenceof surface energy. Analysis of possible applications of surface phenomena in technology. Understanding ofproblems and benefits resulting from decreasing dimensions of objects with the special emphasis on thesemiconductor band...
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Surface Science - 2023/2024
Kursy OnlineThe course is not a full time lecture but on the consultation/handouts. The consulations are held every two weeks. The course is based on the Springer textbook: Surface Science An Introduction Downloadable at: https://link.springer.com/book/10.1007/978-3-662-05179-5 (PG network or vpn access) The goal of the subject is the presentation of basic problems resulting from he existence of interfacebetween material objects...
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Acceleration waves in the nonlinear micromorphic continuum
PublikacjaWithin the framework of the nonlinear elastic theory of micromorphic continua we derive the conditions for propagation of acceleration waves. An acceleration wave, also called a wave of weak discontinuity of order two, can be treated as a propagating nonmaterial surface across which the second derivatives of the placement vector and micro-distortion tensor may undergo jump discontinuities. Here we obtain the acoustic tensor for...
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Fuzzy Control of Waves Generation in a Towing Tank
PublikacjaThis paper presents the results of research related to the transformation of electrical energy into potential and kinetic energy of waves generated on the water surface. The waves are generated to model the environmental conditions for the needs of the model tests. The model tests are performed on model-scale objects to predict the features of full-scale maritime objects. It is done to improve human safety and the survivability...
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JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS
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PREDICTION OF SHIP MOTIONS IN IRREGULAR WAVES BASED ON RESPONSE AMPLITUDE OPERATORS EVALUATED EXPERIMENTALLY IN NOISE WAVES
PublikacjaThe most common methods for predicting ship roll motions in a specified sea state are direct measurements of motions in a representative irregular wave realisation (time domain) or calculations of motions from response amplitude operators (RAOs) in the frequency domain. The result of the first method is valid only for the tested sea state, whilst the second method is more flexible but less accurate. RAO-based predictions are calculated...
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SURFACE & COATINGS TECHNOLOGY
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Magnetism and charge density waves in RNiC2(R=Ce,Pr,Nd)
PublikacjaWe have compared the magnetic, transport, galvanomagnetic, and specific-heat properties of CeNiC2, PrNiC2, and NdNiC2 to study the interplay between charge density waves (CDW) and magnetism in these compounds. The negative magnetoresistance in NdNiC2 is discussed in terms of the partial destruction of charge density waves and an irreversible phase transition stabilized by the field-induced ferromagnetic transformation is reported....
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The propagation of the waves in the CTO S.A. towing tank
PublikacjaThe paper presents the results of research focused on the wave propagation in the CTO S.A. deepwater towing tank. In the scope of paper, the wavemaker transfer function was determined for regular waves, based on the Biésel Transfer Function and further for irregular waves, based on Hasselman model of nonlinear energy transfer. The phenomena: wave damping, wave breakdown and wave reflection, were measured, analyzed and mathematically...
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Orthodontic Waves
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Water Waves
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SHOCK WAVES
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Review of Selected Methods for Prediction of Added Resistance in Following Waves
PublikacjaThe added resistance in waves is a mean value of non-linear, second order reaction of a ship to incoming waves. In the beginning of the 20th century, the experimental methods for investigation of ship hydrodynamics at model scale were developed. They allowed the evaluation of added resistance by measurements in irregular waves (directly) or by measurements in regular waves (in-direct method). The main goal was to find more precise...
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CONTROL OF THE WAVES IN A TOWING TANK WITH THE USE OF A BLACK-BOX MODEL
PublikacjaThe paper describes an adaptive control system of the waves, implemented in the Ship Design and Research Centre, CTO S.A. The purpose of generating the waves in the towing tank is the modelling of the environmental conditions during hydrodynamic model tests. The tests are performed on scale models of towed or free running ships, anchored structures like oil rigs or bottommounted structures, e.g. wind turbines. In the towing tank...
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Wave transmission across surface interfaces in lattice structures
PublikacjaWithin the lattice dynamics formulation, we present an exact solution for anti-plane surface waves in a square lattice strip with a surface row of material particles of two types separated by a linear interface. The considered problem is a discrete analog of an elastic half-space with surface stresses modelled through the simplified Gurtin–Murdoch model, where we have an interfacial line separating areas with different surface...
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Application of guided waves in the evaluation of steel-concrete adhesive connection
PublikacjaThe aim of the paper is the application of guided waves in the evaluation of a condition state of adhesive connection between steel and concrete. The study concerns a push-out specimen consisting of two steel plates glued to opposite faces of a concrete cube with the use of structural adhesive. Wave propagation in the specimen without external load is investigated both experimentally and numerically. The second stage of the investigation...
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Guided waves for nondestructive diagnostics of embedded waveguides
PublikacjaThe thesis concentrates on comprehensive theoretical, numerical and experimental analysis of guided wave propagation in bars embedded in concrete or mortar. The investigations are focused on a particular type of objects representing a laboratory model of a ground anchor. Complex description of wave propagation phenomena in partially embedded bars is given and its application in...
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Surface Chemistry & Experimental Techniques
Kursy Onlinewykłady prowadzone przez prof. G. Jerkiewicza
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Negative impact of constant RPM control strategy on ship NOx emission in waves
PublikacjaIn severe wave conditions, the ship propulsion system is loaded with high fluctuations due to external disturbances. The highly fluctuating loads enforce radical changes in the main engine torque, which in turn demands variation of the fuel rate injected into the cylinders if a constant rotational speed strategy is applied. Therefore, the temperature of gases varies to a large extent during the combustion process in the cylinders....
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Damage detection in a bolted lap joint using guided waves
PublikacjaThe paper presents the experimental investigation of guided waves application to the condition assessment of prestressed bolted connections and a concept of new quantitative indicator. The main goal of the research was the analysis of the influence of the contact conditions changes to the characteristics of a propagating disturbance. The experimental tests were carried out for a single bolted lap joint. The excitation and acquisition...
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Excitation of Waves in a Dispersive Medium. Example of Flow of a Bubbly Liquid
PublikacjaThe excitation of wave motion by an external source and the interaction of modes inherent to a ow in a dispersive medium are considered. Dispersion is caused by the presence of gaseous bubbles in a liquid. A large variety of steady excited waveforms is possible when the exciting wave is also steady and propagates at a constant velocity. The velocities of the exciter and forced waves may be dierent. This leads to a variety of non-stationary...
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Analysis of hull, propeller and engine interactions in regular waves by a combination of experiment and simulation
PublikacjaAnalysis of hull, propeller and engine interactions in regular waves by a combination of experiment and simulation
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Generation and Propagation of Nonlinear Waves in a Towing Tank
PublikacjaThe paper presents the results of the research focused on linear and nonlinear wave generation and propagation in a deepwater towing tank equipped with a single flap-type wavemaker of variable draft. The problem of wave generation and propagation has been theoretically formulated and solved by applying an analytical method; linear and nonlinear solutions were obtained. The linear solution has been verified experimentally. The...
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Detection of defects in PMMA beam using shear waves - numerical simulation and experiment
PublikacjaTest doświadczalny falami sprężystymi jest częścią systemu diagnostycznego belek. Autorzy badają pole przyspieszeń wywołane przepływem fal ultradźwiękowych i jego modyfikacje wynikające z wprowadzonych uszkodzeń belki. Artykuł porównuje wyniki eksperymentalne z symulacjami numerycznymi MES. The experimental test introduced in the paper is the part of the diagnostic system utilizing the elastic waves. The authors investigate the...
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Standing Waves and Acoustic Heating (or Cooling) in Resonators Filled with Chemically Reacting Gas
PublikacjaStanding waves and acoustic heating in a one-dimensional resonator filled with chemically reacting gas, is the subject of investigation. The chemical reaction of A ! B type, which takes place in a gas, may be reversible or not. Governing equations for the sound and entropy mode which is generated in the field of sound are derived by use of a special mathematical method. Under some conditions, sound waves propagating in opposite...