FATIGUE CHARACTERISTICS OF OPEN-END THICK-WALLED CYLINDERS UNDER CYCLIC INTERNAL PRESSURE
Abstract
Thick-walled cylinder fatigue data due to cyclic internal pressure for open-end cylinders in the range of 1,000 to 100,000 cycles to failure and having a diameter ratio of 1.4 to 2.0 at a nominal yield strength of 160,000 pounds per square inch is presented. Also presented are effects of autofrettage on the fatigue characteristics of thick-walled cylinders. Autofrettage substantially enhances fatigue characteristics at stress levels below the corresponding overstrain pressure; the degree of improvement increasing with decreasing stress levels. The rate of improvement in fatigue characteristics increases significantly with diameter ratio in autofrettaged cylinders up to a diameter ratio of 1.8 - 2.0 and to a much smaller degree in the non-autofrettaged condition. The rate of improvement of fatigue characteristics above 2.0 is the same for both the autofrettage and non-autofrettaged cases. Thermal treatment of 675 F for 6 hours after autofrettage does not affect fatigue characteristics and there is a correlation between the cyclic stress level and the area and depth of the fatigue crack to the point of ductile rupture. The depth of the fatigue crack decreases with increasing cyclic stress level. A means for using data from a uni-directional tensile fatigue test to predict the fatigue characteristics of thick-walled cylinders is discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1962
- Accession Number
- AD0284940
Entities
People
- A.n. Reiner
- R. Eisenstadt
- T.e. Davidson