The dependence of the coefficient of static friction of the interface between two bidisperse granular materials on the mass concentration.

Date

4-2012

Degree

Bachelor of Science in Applied Physics

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Junius Andre F. Balista

Abstract

Previous studies on the friction of granular material focused on the following interfaces only: continuous surface-continuous surface, individual grain-continuous surface, and grain material (i.e. aggregate)-continuous surface. Most of these studies also considered monodisperse granular materials. However, phenomena involving interface between two bidisperse granular materials have not been investigated. Here, we determined the coefficient of static friction, ps, of bidisperse granular material-bidisperse granular material interface for various mass concentrations. The bidisperse granular material is made of big (mean diameter = 6.746 mm ± 0.147 mm) and small (3.107 mm ± 0.129 mm) dry tapioca balls. The setup is a modified version of the usual table top friction experiment by constructing a cage-like contraption to hold the granular materials. From 24 trials for each mass concentration, we determined that the mean coefficient of static friction, <1.1.>, of 0%, 25%, 50%, 75% and 100% big grains are 0.727 (standard deviation, a = 0.0124), 0.672 (0.0742), 0.676 (0.0703), 0.673 (0.0512), 0.701 (0.0188), respectively. While the spread of values vary for different mass concentration, the mean coefficient of static friction is independent of mass concentration. These results suggest that it is valid to approximate the coefficient of static friction as a single constant in describing phenomena involving grains differing in sizes alone. PACS: 81.05 Rm, 83.80 It, 62.20 Qp

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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