Structural Integrity of Energy Pipelines: Assessment, Reliability and Optimization

加压钢管被广泛认为是运输大量碳氢化合物产品的最经济手段加拿大能源管道行业运营着大约115，000公里的石油和天然气输送管道。 维持这一庞大的管道网络的完整性和安全运行具有重大的社会和经济意义。 新的知识、模型和方法将有助于管道运营商实现这一目标，具有重要的实用价值。 该研究计划旨在维护钢管道在各种威胁下的结构完整性，包括以下项目，即1）开发基于可靠性的管道腐蚀管理方法，2）开发多目标优化维护策略，3）研究单边拉伸试样用于确定断裂韧性。 在过去的十年中，基于可靠性的管道腐蚀管理计划越来越受到管道运营商的关注，因为这样的计划提供了一个适当的框架，以考虑腐蚀检查和评估中涉及的各种不确定性。项目1）的成果将填补腐蚀缺陷空间相关性方面的知识空白，并提供一个概率框架，以根据检测数据同时推断管道上腐蚀缺陷的数量和增长。 这些方法将导致与腐蚀管道，这是至关重要的复检间隔的确定，准确评估的时间依赖性的可靠性的管道和发展的分阶段的缺陷缓解计划，满足资源和可靠性的约束条件的退化过程的现实建模。 管道的最优维修决策具有重要的社会和经济效益. 项目2）的结果将为管道工程师提供有关维护计划选择的指导，以最大限度地提高可靠性/安全性，同时最大限度地降低成本。 这不仅从管道运营商的角度来看是有价值的，而且从位于管道附近的公众的角度来看也是有价值的。 基于应变的评估正越来越多地用于解决由于例如斜坡移动和地面沉降而施加在管道上的大塑性变形。 断裂韧性阻力曲线是对含有平面缺陷（即裂纹）的管道进行基于应变的评估的关键输入。 在过去的十年中，使用单边拉伸试样来实验测定断裂韧性在管道工业中得到了广泛的关注，因为从这种类型的试样测定的断裂韧性与全尺寸管道的断裂韧性更相关。 项目3）的成果将促进基于单边拉伸试验的断裂韧性测试程序的开发和标准化，这可以导致更准确地评估断裂韧性，从而更准确地对含裂纹管道进行基于应变的评估。

Pressurized steel pipelines are widely recognized as the most economical means to transport large quantities of hydrocarbon products The Canadian energy pipeline industry operates approximately 115,000 km of oil and gas transmission pipelines. Maintaining the integrity and safe operation of this vast pipeline network has significant social and economic implications. New knowledge, models and methodologies that will assist the pipeline operators in achieving this goal are of significant practical value. The proposed research program is aimed at maintaining the structural integrity of steel pipelines under various threats, and consists of the following projects, namely 1) developing reliability-based pipeline corrosion management methodologies, 2) developing multi-objective optimal maintenance strategies, and 3) investigating the single-edge tension specimen for determining the fracture toughness. Over the last decade, the reliability-based pipeline corrosion management program has received growing attentions from pipeline operators because such a program provides an appropriate framework to account for various uncertainties involved in the corrosion inspection and assessment. The outcome of project 1) will fill the knowledge gap with respect to the spatial correlation of corrosion defects and provide a probabilistic framework to simultaneously make inference of the number and growth of corrosion defects on pipelines based on the inspection data. These methodologies will lead to realistic modeling of the degradation process associated with a corroding pipelines, which is critical to the determination of re-inspection interval, accurate evaluation of the time-dependent reliability of the pipeline and development of a phased defect mitigation plan that satisfies both the resource and reliability constraints. Optimal maintenance decisions for pipelines have significant safety and economic benefit to the society and the. The outcome of project 2) will provide guidance to pipeline engineers on the selection of maintenance plans to maximize reliability/safety and minimize cost at the same time. This is valuable not only from the perspective of the pipeline operators but also from the perspective of general public located in the vicinity of the pipelines. The strain-based assessment is being increasingly used to address large plastic deformation imposed on pipelines due to, for example, slope movement and ground subsidence. The fracture toughness resistance curve is a key input in the strain-based assessment of pipelines containing planar defects (i.e. cracks). The use of the single-edge tension specimen to experimentally determine the fracture toughness has gained much attention in the pipeline industry over the last decade, because the fracture toughness determined from such type of the specimen is more relevant to that of the full-scale pipe. The outcome of project 3) will facilitate the development and standardization of the single-edge tension specimen-based fracture toughness testing procedure, which can lead to more accurate evaluation of the fracture toughness and consequently more accurate strain-based assessment of pipelines containing cracks.