School of Astronautics Department of Astronautics Engineering and Mechanics Bachelor of Engineering Non-smooth Approach for Contact Dynamics and Impulse-based Control of Frictional Furuta Pendulum by Hantian Zhang In this thesis, a non-penetrated and physically consistent non-smooth numerical approach has been proposed, by employing the Prox formulation and Moreau’s mid-point time-stepping rule...

Orthodontic forces for sliding tooth movement during space closure are applied at a distance from the centre of resistance of the teeth. For this reason, the teeth will tip until contacts are established between the archwire and diagonally opposite corners of the bracket wings. They will also rotate until the wire contacts opposite corners of the ligature tie or the buccal shield with self-liga...

Frictional properties of soft elastomers have been in question for over half of a century. Early studies on natural rubber originated for the sole purpose of tabulating properties for bulk consumer applications, such as viscoelastic adhesives, tires, and windshield wipers, to name a few. Empirical tabulation of frictional properties persisted until the early 1950’s, when Roth et al. and Thirion...

Liquid-solid phase transition and the change of the frictional force of a system with two hard spheres in a two-dimensional rectangular box are discussed. Under controlling the pressure or the supply of energy from the wall, the solid like state, the solid-liquid temporal coexistence state, and the liquid like state are alternatively observed. The frictional force which works on particles and t...

This study presents a dynamic-induced direct-shear model to investigate the dynamic triggering of frictional slip on simulated granular gouges. An incident P-wave is generated as a shear load and a normal stress is constantly applied on the gouge layer. The shear stress accumulates in the incident stage and the frictional slip occurs in the slip stage without the effect of the reflected wave. T...

Microscopic billow-like wavy folds have been observed along slip planes of the Nojima active fault, southwest Japan. The folds are similar in form to Kelvin–Helmholtz (KH) instabilities occurring in fluids, which implies that the slip zone underwent “lubrication” such as frictional melting or fluidization of fault gouge materials. If the temperature range for generation of the billow-like wavy ...

OBJECTIVE To elucidate some of the parameters determining the frictional behavior of passive, active, and interactive self-ligating brackets during sliding mechanics. MATERIALS AND METHODS A custom jig mimicking the three-dimensional tooth movements that occur during sliding mechanics and an Instron testing machine were used to determine the resistance to sliding of six different self-ligatin...

OBJECTIVE To compare the static frictional forces generated at the bracket/wire interface of stainless steel brackets with different geometries and angulations, combined with orthodontic wires of different diameters. MATERIAL AND METHODS The frictional forces were evaluated with three different types of metal brackets: a passive self-ligating (SmartClipTM, 3M/Unitek, Monrovia, USA), with a mo...

A main concern with artificial turfs is the increased incidences of skin abrasions compared to playing on natural grass. The proliferation of these surfaces draws attention to the skinfriendliness and related test methods of the products. This study focuses on the yarn component and explores the significance of tribopairs in identifying the skin-friendly property of hydrophilically-modified pol...

While frictionless spheres at jamming are isostatic, frictional spheres at jamming are not. As a result, frictional spheres near jamming do not necessarily exhibit an excess of soft modes. However, a generalized form of isostaticity can be introduced if fully mobilized contacts at the Coulomb friction threshold are considered as slipping contacts. We show here that, in this framework, the vibra...