Determination of Johnson–Cook parameters and evaluation of Charpy impact test performance for X80 pipeline steel

• Published in: International journal of mechanical sciences 2020-08, Vol.179, p.105627, Article 105627
• Main Authors: Cao, Yuguang, Zhen, Ying, Song, Ming, Yi, Haijiao, Li, Fagen, Li, Xuyang
• Format: Article
• Language: English
• Subjects: Charpy impact test; Johnson–Cook (J-C) model; Striker radius; Sub-size specimens; X80 pipeline steel
• ISSN: 0020-7403
• DOI: 10.1016/j.ijmecsci.2020.105627

•A detailed experimental work for the determination of J-C material and failure model parameters for high-grade pipeline steel X80.•A comprehensive and systematic analysis of influencing factors on Charpy impact test results of high-grade pipeline steel X80.•The correlation models of Charpy impact test results between SCVN specimens and standard CVN specimens.•The rules of mutual transformation of test results of 2 mm and 8 mm-strikers. Controlling the Charpy impact toughness of materials is the key to the ductile fracture arrest design of pipelines. The finite element method based on Johnson–Cook (J-C) model has become an effective method to assist the experimental study of material impact toughness. In this paper, model parameters of J-C constitutive relation and damage parameters of J-C failure model for X80 pipeline steel have been determined experimentally from quasi-static uniaxial tension tests and Split Hopkinson Pressure Bar (SHPB) tests. Charpy impact test has been simulated using J-C constitutive and failure models with the determined parameters. Reasonable agreements between the simulation and experimental results have been achieved. On this basis, the effects of the pendulum velocity, specimen width and striker radius on Charpy impact test results are studied. The results show that pendulum velocity has negligible influence on Charpy impact test results; the maximum force and impact absorbed energy both have a highly linear relationship to specimen width; Charpy impact test is sensitive to striker geometry, the results measured by 2 mm-striker are obviously smaller than those of 8 mm-striker. Based on the above researches, the impact absorbed energy correlation model between sub-size specimens and standard full-size specimens, the test results transformation rules of the two strikers are established. The methods and results presented in this paper will provide references for dynamic behavior study, impact dynamic design, pipeline safety operation and risk assessment of high-grade pipeline steel. [Display omitted]