Establishing the Correlation between Charpy V-Notch (Cvn) Toughness and Xfem Damage Properties

Abstract

Prompt detection or management of imperfections, such as cracks or crack-like anomalies, in onshore and offshore oil and gas pipelines is one of the main challenges in pipeline maintenance. The presence of cracks can compromise structural integrity, potentially resulting in severe economic and environmental consequences. The repair or replacement of damaged pipe segments incurs substantial costs, which makes accurately evaluating their failure pressures crucial. The failure pressures of pipelines containing surface cracks can be predicted using fracture mechanics-based analytical models, such as CorLASTM and Ln-Sec models, or through numerical tools. A more recently developed numerical approach, known as the eXtended Finite Element Method (XFEM), extends the capabilities of the traditional Finite Element Method (FEM) and offers a more effective means of modelling crack growth. In ABAQUS software, XFEM is often employed in conjunction with the cohesive segment modeling approach, consisting of a damage initiation criterion and a damage evolution law to simulate crack initiation and propagation. In this XFEM-based approach, fracture criteria are typically defined using two damage properties that are specific to the material properties. Similarly, in fracture mechanics models, fracture toughness parameters are also determined either through standard fracture testing of the materials or derived from Charpy energy using empirical correlations. Therefore, this paper presents a study to establish a correlation between Charpy energy and the XFEM damage parameters. The findings of this study are expected to provide pipeline operators with valuable guidance for selecting appropriate XFEM damage parameters based on known Charpy V-Notch impact energy values.

Keywords: Pipelines, fracture toughness, Charpy energy, XFEM, failure pressure