Coupled Dynamic Problems Of The Three Gorges Shiplift

The world famous Three Gorges Project (TGP) is the largest water conservation project ever built in the world. The one-way, single-step vertical shiplift with counterweight is one of the most important structures in the Three Gorges project. According to the navigation requirement, its maximum lifting height is 113m and total lifting weight is about 11,800 tons, including a chamber of 120m x 18m x 4.3m, water, and a ship of up to 3,000 tons in the chamber. The construction and operation of the shiplift is a great technical challenge. Safe operation of the shiplift is extremely important with no margin for error. In this context, we focused on the fully weight balanced, cable lifted vertical shiplift, which was the original design for The Three George's shiplift. In our study, the shiplift system consists of lifting system, the mass counterweights, the moment counterweights, the chamber, water in the chamber and ships in the water. We modeled this complicated mechanical system by including the interaction among rigid body, elastic structure, and fluid motion, coupling between structure and mechanism, and finally sloshing and viscosity effect for fluid flow in the chamber. Based on the coupled dynamic system formulation, we systematically developed the mechanical model, algorithm, and software and analyzed the dynamic behaviors and stability conditions of the shiplift system.Towards developing a mechanical model of the complicated coupled engineering system, in the present thesis we carried out the following researches:1. We derived differential governing equations of water sloshing in the chamber in Chapter 2 and presented a discretization scheme using finite element method in the space domain. Frequencies of a rectangle tank, a cylindrical tank, a cubic tank and tanks of elliptic cross section were calculated to characterize different natural vibration modes. This model also provided us with the flow response in the chamber under external excitation of different frequencies and different durations, as demonstrated here.2. In Chapter 3, we obtained a set of dynamic equations of the chamber and the ship, based on the principles of rigid body dynamics. This model includes chamber motion, ship motion, water sloshing in the chamber, and the coupled oscillation of these components. To this end, we adopted a number of coordinate systems and established transformations among them. Through these analyses, we obtained equivalent static stiffness matrix of ships that represents the water response within the finite domain of a chamber. Because of the asymmetric stiffness and mass matrixes, we applied modal synthesis to convert the...