Bicoherence-based structural health monitoring of fixed offshore structures

Structural integrity management is key to the safe and economic operation of offshore structures. Presently, regular manual inspections are conducted. This is expensive, time consuming, and prone to human error. This paper investigates the possibility of using the bicoherence function of the measured structural acceleration to provide automatic early detection of damage in an offshore structure. The method is shown to be insensitive to typical operating parameter variations and to variations in wave excitation force, and demonstrates that very small changes in stiffness of individual structural members are detectable from measurements of global structural motion.