Effect of Ovality on Shakedown of Pipe Bends

This paper investigates the effect of pipe bend ovality on the shakedown boundary utilizing the cyclic elastic-plastic analysis method. The ASME Code, Section III NB-3653.2 recognizes the effect of the bend ovality on the peak stress only. The manufacturing rules of ASME NB-4223.2 limit the maximum bend cross sectional ovality to 8%. The effect of the bend ovality on the ratcheting boundary has not been well established in the literature. The current study compares the effect of primary mean stress (i.e. pressure) combined with expansion (secondary) cyclic bending on the shakedown boundary of a prototypical pipe bend with ovalized and fully circular cross section.Copyright © 2010 by Atomic Energy of Canada Limited