Frequency Domain Long-Term Efficiency of Viscous Damper in Jacket Platforms Under Random Wave Load

Various types of controlling mechanisms have been investigated to decrease vibrations of different structures, and in many cases, the reliability has been increased with respect to conventional methods of structural optimization. Among them, using passive viscous damper is one of the useful methods to control structure response due to environmental loads. Hence, in this study, the effect of viscous damper on vibration control of jacket platform (case study oil platform SPD2 and Resalat) exposed to wave loads is investigated, and with the sea state, long-term performance of damper to reduce the structural response is introduced for the first time the more suitable than the responses in an especial case. To keep up this purpose, the platform is modeled by finite element method, and wave spectra are radiated to it. Spectral analysis is adopted to investigate the structural response of the jacket platform equipped with viscous dampers, and also, conventional arrangements of dampers are analyzed to acquire optimal one. Then, the economically optimal arrangement of damper is determined. The novelty of this paper is that the results based on the sea states recorded in the long term help one find the optimal arrangement of damper.