Stress Intensity and Fatigue Crack Growth in Multiply‐cracked, Pressurized, Partially Autofrettaged Thick Cylinders*

Abstract

Stress intensity factors are determined for internally and externally cracked, pressurized thick cylinders with partial autofrettage (less than 100% overstrain). The solutions are based on a superposition of existing solutions which does not involve any loss of accuracy. Implications of the stress intensity factor results for the safe‐life design of pressure vessels subjected to fatigue are discussed.

Some Methods of Representing Fatigue Lifetime as a Function of Stress Range and Initial Crack Size

“…Eqn. (8) indicates that a three-dimensional lifetime 'surface' exists, based upon axes logN, logAaand log a,, see Fig. 2.…”

“…4 works in describing fatigue life for the various conditions mentioned above. Table 1 summarizes fatigue results from early and where k T is the stress concentration factor of the through hole or the external notch, a p and a R are the applied and residual hoop stresses determined from the well known expressions for pressure vessels [7,8], and P^ and P^^, are the values of pressure that are applied to the inner surfaces of the through-hole and the growing crack, respectively. This implies, as before, that only the positive part of the stress range is included.…”