A Study on the Optical Measurement of Torstional Stresses

순수 비틀림 응력의 광학적 측정법에 대한 연구

It is well known fact that there is a theoretical analogous relation ship in terms of differential equation between the stress distribution of a bar under pure torsional moment and the deflection of a membrane subjected to a uniform pressure. This relationship has been applied to the experimental determination of torsional stresses with troublesome and elaborative measuring procedure since Griffith's invention of the soap-film apparatus. In this paper, the soap-film was replaced by a highly polished steel plate and whole visualable deflectional contour-line-map was able to obtain by using Michelson Interferometer with Ne-He Gas Laser lignt source enabling to determine the stress distribution in the vicnity of the symmetrical inner-boundary in a section. Experimental results were satisfactory and the margin of error in the measurement was lower than 1%.