Issue 52

B. Paermentier et alii, Frattura ed Integrità Strutturale, 52 (2020) 105-112; DOI: 10.3221/IGF-ESIS.52.09 105 Focussed on the 1st Benelux Network Meeting and Workshop on Damage and Fracture Mechanics Numerical modelling of dynamic ductile fracture propagation in different lab-scale experiments using GTN damage model Benoît Paermentier * , Dimitri Debruyne, Reza Talemi Department of Materials Engineering, KU Leuven, Belgium benoit.paermentier@kuleven.be A BSTRACT . Initiation and propagation of ductile fractures are major consideration during the design of high-pressure pipelines. Consequences of a pipeline failure can be catastrophic thus structural integrity must be ensured over several decades. Traditional lab-scale experiments such as the Charpy V- Notch (CVN) and Drop Weight Tear Test (DWTT), impact experiments on a notched three-point bending sample, are widely used to measure the fracture toughness of a material. However, with increasing wall thickness and the transition to high-grade steels in the pipeline industry, the size-effect of the specimen and inverse fracture became prominent issues. A new testing methodology called the Dynamic Tensile Tear Test (DT3) is currently investigated as to address the issues presented by the current state of the art. In this study, a numerical investigation is conducted on the CVN, DWTT and DT3 experiments to compare the modelling of dynamic ductile fracture propagation in three different testing scales using the Gurson-Tvergaard- Needleman (GTN) damage model. X70 and X100 pipeline steel grades are used to model material behaviour. For each considered lab-scale experiment, the dynamic ductile fracture behaviour was successfully reproduced using the GTN damage model. K EYWORDS . Ductile fracture; High strength steel; FEM; Fracture toughness; GTN. Citation: Paermentier, B., Debruyne, D., Talemi, R., Numerical modelling of dynamic ductile fracture propagation in different lab- scale experiments using GTN damage model, Frattura ed Integrità Strutturale, 52 (2020) 105-112. Received: 31.10.2019 Accepted: 17.01.2020 Published: 01.04.2020 Copyright: © 2020 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION igh-pressure pipelines are still considered as one of the most efficient means of transport for natural gas and other chemical products. Due to the catastrophic consequences of pipeline failure, structural integrity must be ensured over several decades. Therefore, ductile fracture control is a crucial consideration during the design phase. The high cost of the full-scaled experimental campaigns resulted in the development of more economical lab-scale tests such as the well-known Charpy V-Notch (CVN) impact test, Drop Weight Tear Test (DWTT) [1] and more recently the Dynamic Tensile Tear Test (DT3) [2, 3]. Compared to modern pipelines with wall thickness reaching over 20 mm, the CVN has a relatively small standard specimen size with a 10 mm × 10 mm cross section [4]. Extrapolation of the CVN test data has shown to result in dangerous non- H