Nonlinear elastic–plastic stress investigation for two interacting 3‐D cracks in offshore pipelines

Abstract

Under continuous loading conditions, small closely distanced cracks can grow and coalesce into a large one that may subsequently pose a threat to the integrity and safety of structures. Although many research works were carried out for predicting fatigue growth of multiple cracks, few papers focusing on nonlinear elastic–plastic analysis of multiple cracks' fracture behaviours can be referred to. In this study, 3‐D elastic–plastic investigation has been performed on fracture behaviours of two collinear cracks located in offshore pipelines. The influences of the cracks configuration, the separation distance and internal pressure of the pipeline on the crack behaviours are investigated. On the basis of the numerical results, a new strain‐based crack tip opening displacement estimation method is proposed for assessing the fracture behaviour of flawed pipelines with two interacting collinear cracks.

Interaction Assessment of Stress Intensity Factors of Surface Cracks on Thick Cylinders under Tension Force and Bending Moment

“…In terms of the influence of vibrational loading on a cracked component [12][13][14][15] have considered this problem. Previously, Zhang [16,17] used Crack-Tip Opening Displacement (CTOD) to perform 3-D FEA on a circumferentially cracked pipe containing a semi-elliptical surface crack and an elliptical embedding crack. A 3-D elastic-plastic analysis of the interaction behaviors of two collinear cracks was performed.…”

Interaction of double parallel cracks located on a hollow cylinder

“…By the means of crack interaction, the cracks being deeper, the more critical they are, which could lead to crack propagation. In addition, (Y. M. Zhang et al 2015) and (Y. Zhang, Fan, and Xiao 2016) performed 3-D FEA on a circumferentially cracked hollow cylinder with one semi-elliptical surface crack and an elliptical embedded crack by Crack-Tip Opening Displacement (CTOD).…”

Carbon fibre buckle arrestors for offshore pipelines

“…The hazardous subsea pipeline accidents caused by corrosion, 65% were because of external corrosion, many researchers have investigated the collapse of subsea pipelines due to corrosion [1][2][3][4]. Once local collapse initiated, the circular cross-section of the pipe transforms into a dogbone shape, and eventually a flat shape (causing shutdown of the pipeline), as the buckle rapidly propagates along the pipeline [5][6][7][8][9][10].…”