Column-In-Column System in Wave Vibration Control of Tension Leg Platform

Tension Leg Platforms (TLPs) compliant in nature are used for deep-water exploration and production. The oceanic environment reduces the serviceability and productivity of the platform. Conventional TMDs are extensively used to mitigate unnecessary vibrations of TLPs under waves, wind, and currents. A properly designed tuned mass damper (TMD) with a larger mass ratio can diminish the response of such structures effectively. However, the inclusion of a substantial auxiliary mass to a TLP increases the cost and may not be feasible in some cases. To navigate this challenge, present study is attempted to convert a portion of the existing mass of a TLP into a tuned mass by using the column-in-column (CIC) concept. For Tension Leg Platforms (TLPs), the platform's deck relies on support from pontoons and columns. These elements are interconnected with the seabed through a taut-mooring system. The columns and pontoons play a crucial role in providing a substantial submerged volume while minimizing overall weight. Utilizing the CIC concept, each column of TLP is divided into two columns. The inner column is connected with the outer column by spring and dashpot having optimum stiffness and damping ratio so that the system works like a TMD system. The usefulness of the anticipated CIC system in response mitigation of TLP under extreme sea state is elucidated numerically. The outcomes of the numerical investigation, on the whole, suggest that the CIC has the potential to effectively alleviate the unfavourable wave-induced response of TLPs.