Fatigue Strength of Thick-Walled Cylinders Containing Cross Bores with Blending Features

Abstract

This paper reports on an investigation into the fatigue strength of thick-walled cylinders that contain a small transverse hole or cross bore in the cylinder wall having either a chamfer or a blending radius at its intersection with the main cylinder bore. Fatigue tests surprisingly show that plain cross-bore cylinders having thickness ratios K = 1.4 and 2.0 have a fatigue life that is marginally greater than comparable cylinders with blending features. A finite element investigation shows that local high stresses are produced on the surface of blending features and these stresses are considerably greater in magnitude than those found in plain cross-bore cylinders. These stress findings are used to explain the experimental fatigue life results obtained.