All

Mechanics in Engineering ›› 2004, Vol. 26 ›› Issue (3): 0-0.doi: 10.6052/1000-0992-2003-163

• Education Study •    

NUMERICAL ANALYSIS OF PLASTIC LIMIT LOADS OF LOCALLY THINNED ELBOWS

  

  • Received:2003-04-28 Revised:2003-08-18 Online:2004-06-10 Published:2004-06-10

Abstract: Local wall-thinning, as a common defect on the surfaces of pipelines, not only reduces the load-carrying capacities, but also causes serious failure accidents of pipelines. In this paper, a computational method for plastic limit loads is adopted. The plastic collapse analysis of defective pipe elbows under internal pressure and bending moment is performed by the proposed algorithm. The defects considered here include part-through spherical, ellipsoidal and rectangular slots. Based on a number of numerical examples, the limit loads of pipe elbows are computed for a range of geometric parameters. The effects of axial, circumferential, small and large area local wall-thinnings with different sizes on load-carrying capacities of pipe elbows under internal pressure and in-plane bending moment are analyzed. Some typical failure modes corresponding to different configurations of slots and loading forms are studied. The computational results can provide theoretical foundations for the safety assessment of defective pipe elbows.

Key words: elbow, local wall thinning, plastic limit load, numerical analysis