Rough Surface Effect on Meissner Diamagnetism in Normal-Layer of    N–S Proximity-Contact System

The chapter consists of static and dynamic analyses of a fractal rough surface in contact with a rigid flat. The fractal surface is constructed using modified Weierstrass-Mandelbrot function. A rigid flat surface touches the topmost point of the rough surface, which moves towards the rough surface and deforms it. Different contact parameters (e.g., contact force, contact area, contact stress, etc. for varying fractal and material properties are obtained through finite element based static analysis. A parameter denoting the degree of nonlinearity of the contact system is extracted from the force-displacement plot of the surface. This parameter is utilized to explain the dynamic behaviour of the fractal surface which vibrates under the influence of the externally excited rigid flat surface. The dynamic analysis of the contact system is carried out by modelling the contact interface as a single degree of freedom (SDOF) spring-mass-damper system. The dynamic behavior of the system is investigated in terms of frequency response curves, time-displacement plots, and phase plots.

Download Full-text

Contact behavior of functionally graded fractal surface

Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications ◽

10.1177/1464420720942251 ◽

2020 ◽

Vol 234 (10) ◽

pp. 1355-1374

Author(s):

Tamonash Jana ◽

Anirban Mitra ◽

Prasanta Sahoo

Keyword(s):

Rough Surface ◽

Material Properties ◽

Dynamic Contact ◽

Functionally Graded ◽

Contact System ◽

Surface Model ◽

Fractal Surface ◽

Static And Dynamic Analysis ◽

Inhomogeneity Parameter ◽

Force Displacement

Functionally graded surface has been a domain of research interest due to its use in various technologically advanced applications. The work focuses on static and dynamic analysis of rough fractal surface with exponentially graded material properties. The rough fractal surface is modeled in ANSYS with the coordinate points generated using the two variable modified Weierstrass–Mandelbrot function. Material gradation is applied to the rough surface model in such a way that, for any value of the gradation or inhomogeneity parameter, material properties at the top of the rough surface always remain constant. Force–displacement behavior of the fractal surface in contact with a rigid flat surface is determined through finite element simulation. A parameter representing the nonlinearity of the system is extracted from the force–displacement plot. It is found that higher is the inhomogeneity parameter, higher is the nonlinearity of the system. Furthermore, for a certain change in inhomogeneity parameter, the change in nonlinearity is higher for rougher topography. The dynamic contact system is found to be softening in nature, and the softening nature increases with higher inhomogeneity parameter. The phase plot of the vibrating contact system becomes more asymmetric with respect to the velocity axis for higher value of inhomogeneity parameter.

Download Full-text