Abstract
For the most part in pressure vessel design the practice has been to base working stresses on the requirement of overall dimensional stability, little serious consideration being given to the possibility of fatigue failure. The present paper draws attention to the hazardous condition which may exist with commercial and military thick-walled pressure vessels which are subjected to cycles of internal pressure.
Results are presented of repeated pressures tests in the range 103–105 cycles on smooth and rifled bore, autofrettaged and non-autofrettaged cylinders with diameter ratios varying between 1·2 and 2·0. The latter were obtained from 105-mm and 175-mm cannon tube forgings. The material which is roughly equivalent to an SAE 4330 steel is utilized at yield strengths in the range 165 000–180 000 lbf/in2.
It is concluded that autofrettage substantially increases fatigue strength, the rate of improvement increasing with diameter ratio.
For the diameter ratios investigated, the least degree of diameter ratio dependency was exhibited when results were plotted on the basis of maximum hoop stress.
Get full access to this article
View all access options for this article.