Degree Type

Dissertation

Date of Award

1981

Degree Name

Doctor of Philosophy

Department

Engineering Science and Mechanics

Abstract

An experimental study is conducted to determine the influence of the near surface elliptical holes on the stress field when the surface experiences a rapid temperature change. The problem is formulated as a two-dimensional transient problem in a multiply connected semi-infinite region. It is assumed that the quasi-static formulation of thermoelasticity is valid. The experimental technique used was photothermoelasticity by means of heating. The transient thermal stress concentration factors around the elliptical boundary are obtained, and the variation of the stress concentration factor with the geometrical parameters (major and minor axes) and the angular orientation (measured as the angle between the major axis and straight boundary) of the ellipse are investigated;Four different ellipse sizes, with the ratio of the minor to major axis b/a = 0.50, 0.40, 0.33 and 0.30 and five different angular orientations, (theta) = 0 , 22.5(DEGREES), 45(DEGREES), 75(DEGREES) and 90(DEGREES), are used. The results are expressed in terms of non-dimensional variables and empirical equations for the maximum stress (stress concentration factor) for the different angular orientations are developed.

DOI

https://doi.org/10.31274/rtd-180813-4687

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Ibrahim Miskioglu

Language

en

Proquest ID

AAI8128842

File Format

application/pdf

File Size

160 pages

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