Burst Strength of NPS30 Steel Pipes with Dent-Crack Defect

摘要

Pipeline is the common mode for transporting oil, gas, and various petroleum products. Structural integrity of oil and gas transmission pipelines is often threatened by damages such as dent, corrosion, crack, gouge, or any combination of these damages. Such a damage may lead to structural failure in a field pipeline. One of combined defects is dent-crack defect which is a dent defect that contains a crack defect within the dent. Hence, the pipeline operator becomes concerned about the performance and safety of the linepipe if a pipe wall is subject to a dent-crack defect. Research work using full-scale tests and finite element method was undertaken at the Centre for Engineering Research in Pipelines, University of Windsor to study the influence of various internal pressures, diameter-to-thickness ratios, dent depths, crack lengths, crack depths, crack locations, and pipe steel grade on the structural behaviour and the burst strength of NPS30 (30 in diameter) and X70 and X55 grade pipes when a dent-crack defect is developed. This dissertation discusses the experimental and numerical results obtained from this study with the conclusions drawn.