Response control of TLP with Single TMD under wind, wave, and current

Offshore Tension Leg Platforms (TLP) are hybrid structures, that encounter large offsets under random sea. It imposes large displacements, resulting in operational challenges under extreme sea states. The key to safe topside operation is to minimize the response in flexible modes using appropriate control mechanisms. The present study evaluates the response control of TLP with tuned mass dampers under different sea state environments. The damper is positioned such that the mass center of the primary and secondary system is concurrent. It is enabled only with surge motion, which controls the platform surge motion by tuning their frequency ratios. Response control in surge motion is assessed for different mass ratios of the damper. Results show that the RMS value of surge response is effectively reduced for a mass ratio of 0.3, while other mass ratios did not show effective control; the maximum reduction in the surge amplitude is about 26%. The response reduction is essentially due to the phase shift between the nature of the responses with and without tuned mass damper. In addition, the damper helps improve the recentering capabilities observed from the phase plots.