Session: 08-01-01 Waves and Loads

Paper Number: 79607

79607 - Response Mitigation of Floating Platform by Porous-Media Tuned Liquid Dampers 

A porous-media tuned liquid damper (PMTLD) can serve as an eco-friendly, economical, and effective dynamic vibration absorber when installed on long-period structures. Placing porous media within a water tank can enhance damping; therefore, not only the capacity for energy dissipation can be improved, but performance optimization is possible by varying the porous media properties. In this paper, the numerical simulation of the floating platform dynamics coupled with the interior-flow (sloshing in PMTLD) and exterior-flow (water wave) problems are emphasized. An equivalent mechanical model allows the computation of the dynamic resultants of linear PMTLD, while the two numerical methods are adopted to solve the nonlinear sloshing problem in porous media and ambient water wave problem. The first inviscid approach employs a mixed-type boundary value problem solver, which is implemented by the boundary element method (BEM), coupled with a free surface particle tracker, which in particular includes nonlinear damping effects via a quadratic Forchheimer term for PMTLD. The coupling behavior between fluid and structure is solved by the Newmark time integration method. The second viscous approach uses the finite element method (FEM) to spatially discretize the Navier-Stokes equations and handles the free surface via the volume of fluid (VOF) and the level set (LS) equations. The multiphase simulation is implementation by a computational modeling toolkit Proteus for fluid phase and Chrono for solid phase. The correlations between potential-based methods and Reynolds-averaged Navier-Stokes (RANS) analysis will be presented. The PMTLD is designed for a floating platform based on analogy with the design theory for a tuned mass damper (TMD). Numerical results show that the properly designed PMTLD can effectively reduce the structure’s dynamic response in terms of vibration amplitude around resonance. Such damping devices have great potential for practical applications in bridge, offshore platform, and wind turbine design.

Presenting Author: Wen-Huai Tsao Department of Civil and Environmental Engineering, Louisiana State University

Authors:

Wen-Huai Tsao Department of Civil and Environmental Engineering, Louisiana State University
Ying-Chuan Chen KBR
Christopher E. Kees Department of Civil and Environmental Engineering, Louisiana State University
Lance Manuel Dept. of Civil, Architectural and Environmental Engineering, The University of Texas at Austin