Probabilistic assessment of optimum tuned mass damper in offshore platforms considering fluid–structure interaction

In countries with petroleum-based economies, offshore platforms are considered highly vital infrastructures that are subjected to various dynamic loads in their lifetimes. One effective way to reduce the vulnerability of these structures is to apply vibration control systems. This paper investigates the dynamic behavior of the Ressalat offshore platform under vibrations induced by wave-loading with a return period of 100 years in the Persian Gulf region. The Fluid–Structure Interaction (FSI) is considered along with the effect of the added mass which results from platform vibrations inside the fluid. The Modified Endurance Wave Analysis Method (MEWA) is utilized to load the platform. To control the vibrations of this platform, an optimized Tuned Mass Damper (TMD) was designed using a genetic algorithm. Then, probabilistic evaluation of the damper parameters was carried out via Latin Hypercube Sampling (LHS) method. Results represented that the maximum value of acceleration at the deck level has decreased by more than 45% due to the application of an optimally designed damper. An important point in this study is that the uncertainties of the optimal characteristics of the control system, cause reduction in the efficiency of the control system with the probability of 90% and makes improvement with the probability of 10%.