Effect of non-symmetrical corrosion imperfection on the collapse pressure of subsea pipelines. (September 2020)

• Record Type: Journal Article
• Authors: Zhang, Xinhu; Chen, Baiqiao; Guedes Soares, C.
• Is Part Of: Marine structures. Volume 73(2020)
• Publication Date: 2020-09
• Subjects: Collapse pressure -- Corrosion defect -- Non-symmetrical -- Corrosion location -- Parameteric study; Naval architecture -- Periodicals; Offshore structures -- Periodicals; Architecture navale -- Périodiques; Structures offshore -- Périodiques; Naval architecture; Offshore structures; Periodicals; 620.4162
• DOI: 10.1016/j.marstruc.2020.102806
• Languages: English
• ISSNs: 0951-8339

Abstract

Abstract: The effects of non-symmetrical corrosion defects (about the major or minor axis of the ellipse) on the collapse modes and collapse pressures of subsea pipelines are studied using the Finite Element (FE) method. The corrosion defects are represented by a groove of a given length, width, and depth which is created by the "element death" technology. Parametric studies are conducted and the influences of corrosion location angle, length, width, and depth on the collapse pressure are discussed. Several significant and interesting results are achieved: (1) The collapse modes are mainly affected by the corrosion location angle, width, and depth; (2) The collapse pressure of a pipe may increase as the corrosion length, width, or depth increases when the corrosion location angle is small; (3) The longer the corrosion length, the larger the effect of corrosion location angle on the collapse pressure; (4) For collapses controlled by corrosion defect (0.3≤ h / t ≤ 0.7), the relationship between the collapse pressure and corrosion location angle follows a simple cosine function. For collapses controlled by the ovality ( h / t < 0.3), the relationship can be expressed by the combination of straight-line and cosine function. Highlights: The effects of non-symmetrical corrosion defects on the collapse responses of subsea pipelines are studied. The corrosion defect is represented by a groove of a given length, width, and depth. Using the validated finite element models, non-symmetrical collapse modes are obtained. A parametric study is conducted for the effects of corrosion location, length, width, and depth on the collapse pressure. When corrosion depth is more than 0.6t, non-symmetrical defect leads to lower collapse pressure than that of symmetrical.