Application of ECA technology in life assessment of key nodes of deep water jacket

The overall stiffness of the deep water jacket is small, with an inherent period close to the wave frequency, and has significant dynamic response characteristics. The resulting inertial force load is one of the external loads that cannot be ignored. At the same time, under the action of environmental loads such as wind, wave and flow, high-frequency and high-amplitude cyclic stress is easily generated at the pipe joints, which leads to fatigue failure of the structure. Compared with the traditional S-N curve method, the ECA evaluation technology takes into account the influence of initial defects and residual bearing capacity of structures with defects. Therefore, based on the ECA evaluation technology, combined with the dynamic response characteristics of deep water jacket, this paper proposes a set of ECA evaluation process suitable for deep water jacket. In this paper, taking a deep-water jacket platform as an example, the influence of the dynamic response of the platform is introduced, and the fatigue life of the structure is calculated. Compared with the traditional S-N curve method, the rationality of the method applied to engineering practice is verified.