Session: DA-12-02 The Noel O'Dowd Memorial Symposium on Fracture: Fracture-2

Paper Number: 154560

154560 - Bending Fracture Behavior of D1219 X80 Steel Pipeline With Girth Weld Crack Defects: A Full-Scale Experimental and Numerical Investigation 

Abstract: 

The cracking limit state of pipeline girth weld is affected by many factors such as material, defect, load , etc. The full-scale pipeline test can truly reflect the load of pipeline girth weld. It is the only test method that can consider the influence of pipeline medium pressure on the fracture failure of girth weld, and it is also the most accurate method to evaluate the true strain capacity of girth weld. This study conducted two four-point bending fracture tests on full-scale pipelines with crack defects and performed in-depth analysis of the mechanical responses through numerical inversion. The tested pipelines had dimensions of 1219 mm×22 mm, with defect sizes of 15 mm × 300 mm and 16.5 mm × 300 mm, respectively. Additionally, full-material round bar tensile tests and CVN tests were carried out to determine detailed material property parameters and fracture toughness. Strain gauges and Digital Image Correlation (DIC) system were used for real-time monitoring of key behaviors such as crack tip blunting. By meticulously recording the load-displacement response during the tests and combining the synchronous monitoring results from external strain gauge and DIC systems, a deep comparative analysis was conducted to identify the critical failure states of the welded joints under both test conditions. A numerical simulation model of the full-scale pipeline was constructed using the finite element software ABAQUS, which simulated the CTOD-Distal strain curves during the tests and determined the critical strain capacity. Compared with experimental results, the error was controlled within 10%, fully validating the high accuracy and reliability of the model. The data obtained from this full-scale test serve as an important basis for correcting the fracture toughness test results of small-scale standard specimens, verifying the numerical model of simulated pipeline girth weld fracture and the applicability evaluation method, supplementing the international 1219 mm large-diameter high-grade steel pipeline strain capacity database.

Presenting Author: Xiaoben Liu China University of Petroleum-Beijing

Presenting Author Biography: Liu Xiaoben, Ph.D., Associate Professor, Doctoral Supervisor, and Director of the Department of Oil and Gas Storage and TransportationEngineering at China University of Petroleum (Beijing). As the young leader of the safety team for oil and gas storage and transportation facilities,I have been engaged in teaching and research on the intrinsic safety and integrity evaluation of oil and gas storage and transportation facilities fora long time. I have led 5 national/provincial level vertical projects, more than 40 enterprise and public research projects, published more than 60papers as the first/corresponding author, and more than 30 top or important international journal papers in this field. I have obtained 3 softwareworks, 5 patents, participated in the approval of 1 ISO standard, and 1 national standard, 2 industry standards, published 1 translated work, andwon 1 provincial and ministerial level special prize, 2 first prizes, and 2 second prizes. In recent years, research has been focused on majordemand issues in the field of oil and gas storage and transportation safety in China, such as the failure of circumferential welds in high-gradepipelines, the interaction between geological disasters and pipelines, the safety evaluation of station pipeline systems and facilities, and theevaluation of foundation settlement and integrity of large storage tanks; At the same time, we are committed to promoting numerical simulationof oil and gas pipeline structures, digital twin technology, and exploring digital technologies for pipeline intrinsic safety based on multi-sourceperception of the industrial Internet of Things.

Authors:

Xiaoben Liu China University of Petroleum-Beijing
Haonan Zhang China University of Petroleum-Beijing
Jiaqing Zhang China University of Petroleum-Beijing
Qingshan Feng China Oil & Gas Pipeline Network Corporation
Lianshuang Dai China Oil & Gas Pipeline Network Corporation
Dong Zhang China University of Petroleum-Beijing
Mengkai Fu China University of Petroleum-Beijing
Hao Wang China University of Petroleum-Beijing
Hong Zhang China University of Petroleum-Beijing