Engineering critical assessment on offshore pipelines

• Main Author: Tan, Wendy Si Xia
• Other Authors: Xiao Zhongmin
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/60982
• Institution: Nanyang Technological University

Over decades, pipes had been used to transport oil and gases from one point to another. It is the safest and simplest form of transportation method. Often, the pipe length and size required can be large and hence welding is employed to connect the piping together to form a long transportation trail. At these welded regions, fatigue crack are commonly found and when these crack propagation take place it will lead to material failure. This failure in pipelines is unacceptable. Huge amount of Investment had been made to research on the material properties and crack characteristics of these weld regions. Non-destructive testing is one of the methods adopted for such analysis. The objective of this project is to carry out full investigation on the fatigue crack at welded region with finite element software, ABAQUS. This report will present the results of embedded crack at welded region of the pipe, simulated to perform investigation on the crack propagation at different crack depth, a, of 2mm, 6mm and 8mm, crack length to depth ratio, b/a, of 1, 3 and 5. The Internal pressure at the pipe inner layer of 0MPa, 10MPa and 20MPa is also considered for each case. The understanding of fracture mechanics is implemented and crack tip opening displacement (CTOD) is applied to these failure analysis. The effects of tensile loading displacement condition on the circumferential crack growth are also presented in this report.