Finite Element-based Methods for Dent Assessment on Pipelines
Date
2023-12-19
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Abstract
As a well-developed form for energy transportation over wide ranges and long distances, pipelines always encounter various threats in service. In recent years, with the strong demand of clean energy, hydrogen transport in existing pipelines induces new challenges to the pipelines. Dent is a common mechanical defect present on pipelines, compromising structural integrity and causing pipeline failures. To date, there have been limited methods available to assess dent, and a dent combined with other types of defects such as corrosion. In this work, novel methods and criteria were developed for assessment of pipeline dent, corrosion in dent and hydrogen distribution at the dent using finite element (FE) modeling. Denting and spring-back processes were modeled and plain dents were created on the pipeline. A new criterion based on ductile damage failure indicator analysis was proposed. Pressure-bearing capacity was assessed on corroded pipelines containing a dent, where the mutual interaction between corrosion and the dent were determined. In addition, a method was developed to assess the corrosion in dent by considering both mechanical and electrochemical forces. For dented pipelines repurposed for transporting hydrogen gas, a FE-based model was developed to determine the stress/strain and H atom concentrations at the dent, where denting, spring-back and cyclic loading processes were modeled. Furthermore, the hydrogen-induced crack initiation on the pipeline subject to denting process was investigated using the phase field method.
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Citation
Zhao, J. (2023). Finite element-based methods for dent assessment on pipelines (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.