Vibration Control Simulation of Offshore Platforms Based on Matlab and ANSYS Program

The optimal parameters of the wideband multiple extended tuned mass dampers (METMD) system have been studied using on the Matlab and ANSYS programs. The theoretical optimal parameters of the METMD system and the platform are obtained based on their motion equations. The theory analysis using Matlab shows that: 1) the platform has the better vibration control effect when the nondimensional frequency bandwidth Ω, which is the ratio of the frequencies range to the controlled (target) platform’s natural frequency, is in [0.35,0.6]; 2) the damping coefficient ξ of the ETMD systems is in [0.05,0.15] and 3) the number of the ETMDs is 5 when Ω=0.45 and ξ=0.1. A mega-frame platform with the METMD vibration control system is chosen as an example to test the theoretical results. The FEM simulation using ANSYS program shows that the vibration decreased ratios of the whole platform under the three different random wave forces are 38.7%, 33.7% and 44.7% respectively. The METMD has a good vibration control effect on the mega-platform.