Assessment of pipeline dent strain severity using surface interpolation

使用表面插值评估管道凹痕应变严重程度

• 批准号: 506836-2016
• 负责人: Adeeb, Samer
• 金额: $ 1.36万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=643480
• 关键词: Assessment; pipeline; dent; strain; severity

Current trends in the analysis of dents in pipeline has been and is still turning the focus of pipeline dent integrity management schemes on the localized strain distribution rather than the traditional dent depth based criterion for reasons well documented in history and research. The strain based evaluation of dent severity however is limited by the available techniques for evaluating the strain distribution in affected regions of the pipeline as the existing numerical solvers used to perform nonlinear finite element analysis (FEA) are expensive and computationally demanding and the available closed form expressions in the codes are over simplified in assumptions. In this study a mathematical model is proposed for the strain evaluation of dented pipelines. The model employs the use of three dimensional third order cubic spline functions for performing dent strain severity analysis. This novel approach discretizes the displacement components associated with the dent based on the linear elastic shell theory to develop a continuous yet differentiable surface contour of the dent. The discretized displacement components create a platform that provides operators with the liberty to constrain or release the strain based model from underlying assumptions and allows for flexibility in the choice of the strain measure. The inclusion of the third direction in this study allows for the evaluation of the shear strain components previously neglected in existing analytical models. The objective of this proposal is to investigate the correlation between the strains predicted by the mathematical model and those predicted from FEA thus indicating the possibility of performing a more detailed strain analysis on dented pipelines without having to resort to FEA. Finally, a criterion for prioritizing dent digs will be developed based on the results of this project.

当前管道凹痕分析的趋势已经并将继续将管道凹痕完整性管理方案的重点转向局部应变分布，而不是传统的基于凹痕深度的标准，原因在历史和研究中有充分记录。然而，基于应变的凹痕严重程度评估受到用于评估管道受影响区域的应变分布的可用技术的限制，因为用于执行非线性有限元分析（FEA）的现有数值解算器价格昂贵且计算要求高，并且代码中可用的封闭形式表达式在假设中被过度简化。在这项研究中，提出了一个数学模型来评估凹陷管道的应变。该模型采用三维三阶三次样条函数来执行凹痕应变严重性分析。这种新颖的方法基于线弹性壳理论离散化与凹痕相关的位移分量，以形成连续但可微分的凹痕表面轮廓。离散位移分量创建了一个平台，使操作员可以自由地从基本假设中约束或释放基于应变的模型，并允许灵活地选择应变测量。本研究中包含第三方向可以评估先前在现有分析模型中忽略的剪切应变分量。 该提案的目的是研究数学模型预测的应变与 FEA 预测的应变之间的相关性，从而表明无需诉诸 FEA 对凹痕管道进行更详细的应变分析的可能性。最后，将根据该项目的结果制定优先考虑凹痕挖掘的标准。