Analysis of Pipe Bends With Symmetrical Noncircular Cross Sections

Abstract

A thin shell analysis is presented for pipe bends with symmetric noncircular cross sections under in-plane bending or internal pressure, using the static-geometric analogy and neglecting end effects. Any symmetric shape is possible but the analysis mainly concerns cross sections with double symmetry; an investigation of two-lobe (oval) and four-lobe cross sections demonstrates that pipe bend flexibility is almost inversely proportional to flank radius if the pipe wall is thin. Pressurizing a pipe bend of oval cross section produces a similar hoop stress distribution to that of a bending moment straightening the pipe.