Study of Local Vibration Control for the Offshore Platform Based on the Mega-Frame Theory

In order to control the vibration of the W12-1 platform built in the Beibu Gulf, the reduced model of the local platform was made using the finite elements software. Modal analyses showed that the vibration modal shape distortion caused by the insufficient stiffness of local platform was the main reason that caused the whole platform’s vibration. In order to eliminate the distortion, a mega-beam was constructed based on the local platform on which the compressors were installed by increasing the stiffness of beams and changing the position of the inclined struts using the mega-frame theory. Theoretical analysis showed that the mega-beam had the huge holistic stiffness and could remove the vibration modal shape distortion effectively. The computational simulation results showed that the vibration can be restrained effectively. After the anti-vibration method executing, the on-site retesting results showed that the average vibration level of zone I was reduced by 75.08%. The vibration levels of zone II and III were reduced by 49.36% and 49.13% respectively. So, the vibration control methods had the perfect effect on W12-1 platform.