Fatigue crack growth life of thick-walled cylinders with an external radial crack

• Published in: International journal of fatigue 1999-02, Vol.21 (2), p.135-146
• Main Authors: Koh, Seung-Kee, Na, Eui-Gyun
• Format: Article
• Language: English
• Subjects: Applied sciences; Autofrettage residual stress; Exact sciences and technology; Fatigue; Fatigue crack growth life; Mean stress; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Stress intensity factor; Thermal loading analogy
• ISSN: 0142-1123; 1879-3452
• DOI: 10.1016/S0142-1123(98)00067-X

To estimate the fatigue crack growth life of the autofrettaged cylinder with a straight-fronted radial crack emanating from an external groove, stress intensity factors of the external cracked cylinder due to internal pressure and autofrettage loadings were calculated using finite element methods and thermal loading analogy. The fatigue life of the cylinder based on fracture mechanics concepts was predicted and compared to the experimental fatigue life determined from the simulation fatigue tests using C-shaped specimens taken from the thick-walled cylinder made of ASTM A723 high strength steel. Mean stress effects caused by the autofrettage residual stresses were taken into account for the fatigue life calculations. Good correlations were found between the predicted and experimentally simulated fatigue lives within a factor of 2 for both single and double grooved cylinders. Predicted fatigue crack growth lives of the double grooved cylinders with a shorter initial crack were about 1.5–6 times longer than those of the single grooved cylinders, depending on the level of autofrettage.