Analysis of Fatigue Behavior of 66 kV Dry-Type Submarine Cable for a Flexible Pull-In Installation System

초록

Submarine power cables for offshore wind farms experience continuous cyclic loading from environmental forces and floating-platform motions, making fatigue performance a critical design factor. This study combined global and local analyses to investigate the fatigue behavior of a 66 kV dry-type submarine cable installed using a flexible pull-in installation system. A global dynamic analysis using site-specific meteorological and oceanographic data provided time-series displacement responses that were used to evaluate the fatigue damage to the metallic components of the cable. The results indicated that the minimum fatigue life of 8.71 x 104 cycles occurred at the upper metallic sheath near the fixed end, with a corresponding cumulative damage of 1.147 x 10-5. Fatigue accumulation was predominantly governed by lateral (y-direction) displacement, while axial and vertical displacement components contributed minimally. Furthermore, the predicted fatigue life of the metallic sheath varied by a factor of up to 3.6 depending on the selected curve, comparing the cyclic stress amplitude and number of cycles to failure (S-N curve), highlighting the importance of accurate material fatigue data. These findings emphasize the need for careful evaluation of the environmental loading and sheath fatigue properties in flexible pull-in installation system-based submarine cable system designs.

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