STRESS ANALYSIS OF MITER JOINT IN PIPELINE UNDER INTERNAL PRESSURE OR IN-PLANE BENDING LOADING

摘要

This paper presents an elastic stress analysis for miter joints in a pipeline under internal pressure or in-plane bending. Using the three-dimensional theory of elasticity, Green and Emmerson [1] obtained two general expressions of hoop and axial stresses for a mitered pipe, and two specific solutions at the plane of joint for the loading cases of internal pressure and in-plane bending. However, their solution of axial stress for bending case is incorrect, and the stress variations with the pipe axis are not provided. Based on their general expressions, the closed-form solutions of hoop and axial stresses are obtained as functions of the radial location r, the circumferential angle θ, and the half miter angle α, in addition to the applied loading, geometry and material parameters. From these results, the solutions of hoop and normal stresses are obtained at the plane of joint for the two loading scenarios.The proposed theoretical solutions are then validated by three-dimensional finite element results, respectively for elastic loading cases of internal pressure and in-plane bending. The comparison shows that all proposed theoretical solutions of hoop and axial stresses at the plane of joint and in the pipe are in good agreement with the finite element results for both loading cases. The stress analysis shows that the maximum tensile stresses occur on the outside surface at the intrados for the two loading cases, the maximum stresses increase with increasing miter angle, and the axial effect of miter joint stresses on a pipe is limited to length scales in a fraction of the pipe diameter.