Accurate Measurement of Residual Stresses of Glass Rods by Photoelasticity

Title & Authors
Accurate Measurement of Residual Stresses of Glass Rods by Photoelasticity
Baek, Tae-Hyun;

Abstract
Risidual stress of cylindrical glass rods are measured by photoelasticity to study the variation of stresses with respect to heat treatment temperatures. In order to measure the stresses accurately, fringe sharpening and multiplication techniques are applied to the determination of photoelastic fringe orders. Filon's separationmethod is used to resolve circumferential and redial stress ocmponents from isochromatic fringes which are the same as in-plane maximum shearing stresses. According to the photoelastic measurements, residual stress is increased as the heat treatment temperature of the rods is raised from $\small{560^{\circ}C}$ to $\small{650^{\circ}C}$ All the circumferential stress components are changed from tensile stresses to compressive ones at approximate $\small{R_m}$/$\small{R_o}$ = 0.6, where $\small{R_o}$/ is outer radius and $\small{R_m}$any measured radius. This analysis shows that residual stresses of the glass rods approach zero if the rods are heat-treated near the strain point.
Keywords
Residual Stress Analysis;Photoelasticity;Firinge Sharpening;Fringe Multiplication;Digital Image Processing;Stress in Glass;Filons Method;Photoelastic Stress Separation;
Language
Korean
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