Photoelastic Study on Flat Bars with a Double Notch on One Edge Subjected to Pure Bending

Abstract

Flat bar specimens of Epoxy Resin with a double notch on one edge were subjected to pure bending. The double notch consisted of a primary circular or 60°-V notch and a secondary U notch formed at the base of the primary notch. The effects of the root radius and the depth of the primary notch and also that of the depth of the secondary notch on the stress concentration factor were investigated. The stress concentration factor showed a nearly similar change to that of a single notch when the depth of the secondary notch was varied. This was also true in the case of the variation in the depth of the primary notch. As to the effect of the root radius of the primary notch, the stress concentration factor made a reverse change to that of a single notch. In all cases examined, the stress concentration factors of a double notch showed smaller values than the product of the independent stress concentration factors of a primary and a secondary notch.