Corrosion fatigue is identified as the main failure mechanism for structures working in severe corrosive medium subjected to cyclic rotating bending fatigue, for example crude oil storage tank (COST). Emphasis is placed on the study of corrosion pit formation and the development of cracks from pits. An improved equivalent initial flaw size (I-EIFS) is proposed for corrosion fatigue life prediction. Based on the concept of equivalent initial flaw size (EIFS), pitting corrosion and small crack growth are equivalent to a part of long crack growth process in corrosion fatigue process. Pitting and crack propagation are quantified throughout the fatigue loading thereby allowing a model to be developed that included the stages of pit development, pit-to-crack transition and crack growth in order to predict the fatigue life. A corrosion fatigue life prediction case is adopted to demonstrate the effectiveness of the proposed model. Based on the proposed model, failure analysis and stress calculation are performed to predict the corrosion fatigue life of COST, which provides a method for the life prediction of COST. The validity of proposed method is verified by comparing the service life of COST.

腐蚀疲劳被认为是在经受周期性旋转弯曲疲劳的重度腐蚀性介质（例如原油储罐）中工作的结构的主要失效机理。重点放在腐蚀蚀坑形成和腐蚀裂纹扩展方面的研究。提出了一种改进的等效初始缺陷尺寸（I-EIFS），用于腐蚀疲劳寿命的预测。基于等效初始缺陷尺寸（EIFS）的概念，点蚀和小裂纹扩展相当于腐蚀疲劳过程中长裂纹扩展过程的一部分。点焊和裂纹扩展在整个疲劳载荷中都得到了量化，从而可以开发出一个模型，该模型包括点蚀发展，点蚀至裂纹的过渡以及裂纹扩展的各个阶段，以预测疲劳寿命。以腐蚀疲劳寿命预测为例，验证了该模型的有效性。在此模型的基础上，进行了失效分析和应力计算，以预测COST的腐蚀疲劳寿命，为COST的寿命预测提供了一种方法。通过比较COST的使用寿命，验证了所提方法的有效性。