Partial-slip frictional response of rough surfaces
نویسندگان
چکیده
If two elastic bodies with rough surfaces are first pressed against each other and then loaded tangentially, sliding will occur at the boundary of the contact area while the inner parts may still stick. With increasing tangential force, the sliding parts will expand while the sticking parts shrink and finally vanish. In this paper, we study the fractions of the contact area, tangential force and tangential stiffness, associated with the sticking portion of the contact area, as a function of the total applied tangential force up to the onset of full sliding. For the numerical analysis randomly rough, fractal surfaces are used, with the Hurst exponent H ranging from 0.1 to 0.9. Numerical simulations by boundary element method are compared with an analytical analysis in the framework of the Greenwood and Williamson (GW) model. In both cases, a universal linear dependency between the real contact area fraction in stick condition and the applied tangential force is found, regardless of the Hurst exponent of the rough surfaces. Regarding the dependence of the differential tangential stiffness on the tangential force, a linear relation is found in the GW case. For randomly rough surfaces, a nonlinear relation depending on H is derived.
منابع مشابه
Structures, solvation forces and shear of molecular films in a rough nano-confinement
Investigations of surface roughness effects on the structure, dynamics and rheology of a molecular fluid (hexadecane) confined between solid (gold) surfaces, through the use of large-scale molecular dynamics simulations, reveal a remarkable sensitivity to the confining surface morphology. A most significant reduction of the ordering propensity is found in films confined by stationary rough surf...
متن کاملStick-slip friction of gecko-mimetic flaps on smooth and rough surfaces.
The discovery and understanding of gecko 'frictional-adhesion' adhering and climbing mechanism has allowed researchers to mimic and create gecko-inspired adhesives. A few experimental and theoretical approaches have been taken to understand the effect of surface roughness on synthetic adhesive performance, and the implications of stick-slip friction during shearing. This work extends previous s...
متن کاملMeasurement of no-slip and slip boundary conditions in confined Newtonian fluids using atomic force microscopy.
We report measurements of slip length at smooth and rough hydrophilic silica surfaces, using the hydrodynamic force measurement atomic force microscope (AFM). There has been some debate in the literature as to whether the boundary condition between a solid and a wetting fluid is one of no-slip or partial-slip; in particular the results of Neto et al. (C. Neto, V. S. J. Craig and D. R. M. Willia...
متن کاملExistence of Weak Solutions for a Nonlinear Elliptic System
Injection molding is a manufacturing process for producing parts from both thermoplastic and thermosetting plastic materials. When the material is in contact with the mold wall surface, one has three choices: i no slip which implies that thematerial sticks to the surface ii partial slip, and iii complete slip 1–5 . Navier 6 in 1827 first proposed a partial slip condition for rough surfaces, rel...
متن کاملSustained frictional instabilities on nanodomed surfaces: stick-slip amplitude coefficient.
Understanding the frictional properties of nanostructured surfaces is important because of their increasing application in modern miniaturized devices. In this work, lateral force microscopy was used to study the frictional properties between an AFM nanotip and surfaces bearing well-defined nanodomes comprising densely packed prolate spheroids, of diameters ranging from tens to hundreds of nano...
متن کامل