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

中文翻译：

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非对称腐蚀缺陷对海底管道坍塌压力的影响

摘要 使用有限元（FE）方法研究了非对称腐蚀缺陷（关于椭圆的长轴或短轴）对海底管道倒塌模式和倒塌压力的影响。腐蚀缺陷由“元素死亡”技术产生的给定长度、宽度和深度的凹槽表示。进行了参数研究，讨论了腐蚀位置角度、长度、宽度和深度对坍塌压力的影响。取得了几个重要而有趣的结果：（1）坍塌模式主要受腐蚀位置角度、宽度和深度的影响；(2)当腐蚀位置角较小时，管道的坍塌压力可能随着腐蚀长度、宽度或深度的增加而增加；(3)腐蚀长度越长，腐蚀位置角度对坍塌压力的影响越大；(4) 对于腐蚀缺陷控制的坍塌(0.3≤h/t≤0.7)，坍塌压力与腐蚀位置角的关系服从简单的余弦函数。对于由椭圆度控制的坍塌 (h/t