An experimental and numerical study on inward integral buckle arrestors for pipe-in-pipe systems

Abstract

ABSTRACTA type of improved device, designated as inward integral buckle arrestor, is introduced for the pipe-in-pipe (PIP) systems. The experiments have been performed to reproduce the buckle propagation and crossover scenarios of the PIP installed with such devices in a hyperbaric chamber under external pressure. Based upon the experimental observations, dedicated finite element models for test specimens are developed to simulate the whole process of a propagating buckle crossing over an inward integral arrestor to the downstream PIP under the quasi-static, steady-state conditions. Through extensive parametric dependence analyses, the potential buckle propagation and crossover modes are identified, and a reasonable empirical formula of the crossover pressure of the arrestors for the PIP systems is established. The corresponding empirical design formula and lower bound envelope line are proposed to estimate the arresting efficiency of such devices in the preliminary design stage.