Subsea jumpers play a critical role in subsea oil and gas production. Structural damage such as cracks is inevitable in subsea jumpers due to the harsh marine environment (internal fluid flow corrosion, high temperature and pressure, etc.). However, the current research on damage detection and evaluation of subsea jumpers is limited, particularly in cases of slight damage. This study thus proposes a method to identify cracks in subsea jumpers based on the modal characteristics and fractal theory. The accuracy of the method is verified by comparing the finite element simulation method via APDL and the analytical method via MATLAB. In addition, the sensitivity of the method to noise is investigated. The results indicate that the method accurately identifies cracks (single and multiple) with a minimum depth of 0.2 mm in various locations on subsea jumpers. This study may hold significant reference value for improving the safety and reliability of subsea jumpers.
Subsea jumper, damage detection, small crack, modal characteristics, fractal theory