Makine Mühendisliği Bölümü Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.11779/1944
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Browsing Makine Mühendisliği Bölümü Koleksiyonu by Journal "European Journal of Physics"
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Article Citation - WoS: 4Citation - Scopus: 6Development of an Improved Mathematical Model for the Dynamic Response of a Sphere Located at a Viscoelastic Medium Interface(IOP, 2021) Körük, HasanA comprehensive investigation on the static and dynamic responses of a sphere located at elastic and viscoelastic medium interfaces is performed in this study. First, the mathematical models commonly used for predicting the static displacement of a sphere located at an elastic medium interface are presented and their performances are compared. After that, based on the finite element analyses, an accurate mathematical model to predict the static displacement of a sphere located at an elastic medium interface valid for different Poisson's ratios of the medium and small and large sphere displacements is proposed. Then, an improved mathematical model for the dynamic response of a sphere located at a viscoelastic medium interface is developed. In addition to the Young's modulus of the medium and the radius of the sphere, the model takes into account the density, Poisson's ratio and viscosity of the medium, the mass of the sphere and the radiation damping. The effects of the radiation damping, the Young's modulus, density and viscosity of the medium and the density of the sphere on the dynamic response of the sphere located at a viscoelastic medium interface are explored. The developed model can be used to understand the dynamic responses of spherical objects located at viscoelastic medium interfaces in practical applications. Furthermore, the proposed model is a significant tool for graduate students and researchers in the fields of engineering, materials science and physics to gain insight into the dynamic responses of spheres located at viscoelastic medium interfaces.Article Citation - WoS: 11Citation - Scopus: 14Modelling Small and Large Displacements of a Sphere on an Elastic Half-Space Exposed To a Dynamic Force(IOP Publishing, 2021) Hasan KörükSpheres at medium interfaces are encountered in many applications, including in atomic force microscopy or indentation tests. Although the Hertz theory describes the contact mechanics between an elastic sphere and an elastic half-space for static loading and small deformations very well, there is a need to consider the density of the medium, the mass of the sphere and the radiation damping for dynamic loading to obtain reliable results. In this study, an analytical model for predicting the small and large displacements of a sphere on an elastic half-space exposed to a dynamic force is developed. For this purpose, after summarizing a mathematical model that has recently been proposed for the sphere at a medium interface, a finite element model for the sphere at an elastic interface is developed. Based on the comparison of the mathematical and finite element models, an improved analytical model for the sphere at an elastic interface is developed. In addition to considering the elastic properties of the medium and the size of the sphere, the model developed here takes into account the density of the medium, the mass of the sphere, and the radiation damping, and the model is valid for small and large sphere displacements. The developed model can be used to understand the dynamic responses of spherical objects at medium interfaces in practical applications. Furthermore, the proposed model is a remarkable tool for undergraduate and graduate students and researchers in the fields of engineering, materials science and physics to gain insight into the dynamic responses of spheres at medium interfaces. © 2021 European Physical Society.