PHASE ANALYSIS ON THE MECHANISM OF TMD AND MITIGATION OF ICE-INDUCED VIBRATIONS FOR JACKET PLATFORMS WITH TMD

TMD (Tuned mass damper) which has been widely used in civil engineering, is evaluated to see if it is valid to eliminate ice-induced vibrations of jacket structures in Bohai Sea. Analytical derivation of equations is conducted to determine the parameters of TMD primarily, and FEM analysis is performed to check the effect on specific jacket platforms. However, because of the randomness of dynamic ice forces, it is difficult: to evaluate the applicability of TMD on ice-resistant structures using conventional methods. Accordingly, a time domain phase analysis is used to analyze the equivalent forces of TMD to the main structures, and a criterion based on phase analysis is presented to describe the effect of TMD under random ice excitations, based on this, frequency domain and time domain analysis is used to discuss the effectiveness of TMD, it is concluded that TMD system is valid to reduce steady state vibration under ice actions. On the other hand; according to the time domain analysis of the mechanism of TMD