Design Procedure for Flexibility Factors of 90-Deg Curved Pipe Having Various Tangent Lengths (Design Paper)

Abstract

A simple design procedure, based on 175 finite element analyses, was derived to predict the flexibility factor due to an in-plane or out-of-plane moment for a 90-deg curved pipe with end constraints composed of tangents of any length terminated by rigid flanges and no internal pressure loads. The results of this design procedure were then compared to flexibility factors obtained from additional finite element analyses and experimental work. Flexibility factors calculated using the design equations in the Power Piping Code (ANSI/ASME B31.1-1986) were also compared to all finite element and experimental work. It was found that this design procedure more accurately predicts the flexibility factors than the Power Piping Code.