Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/17323
Title: Hydroelastic response of interconnected floating beams modelling longish very large floating structures
Authors: MUHAMMAD RIYANSYAH
Keywords: hydroelastic analysis, very large floating structure, vlfs, boundary element method, finite element method, interconnected floating beams
Issue Date: 29-Oct-2009
Source: MUHAMMAD RIYANSYAH (2009-10-29). Hydroelastic response of interconnected floating beams modelling longish very large floating structures. ScholarBank@NUS Repository.
Abstract: Very large floating structure (VLFS) technology is relatively new approach to create a new land parcel from the sea. It has several advantages over the conventional land reclamation approach, such as cost effective in large water depth and less negative impacts on the environment. Interestingly, it can also be adopted to harness the wave energy to generate electricity. One of the important aspects in the design of VLFS is its hydroelastic response under wave actions. This thesis is concerned with the hydroelastic response of interconnected floating beams. The floating beams are used to model longish-type VLFS whose horizontal dimension in one direction is significantly large than in the other direction. For the hydroelastic analysis, a numerical solution method in frequency domain framework is developed. The fluid is modelled as ideal fluid and the floating beam is modelled by Euler-Bernoulli beam. The Boundary Element Method (BEM) and the Finite Element Method (FEM) are applied to solve the governing equations of the fluid motion and the beam equation of motion, respectively. The aims are to find ways to improve the wave-induced response of the floating beam system. Depends on the purpose of the floating beam system, such improvement in the response can be a reduction or an increase. In the first phase of the study, the use of auxiliary beams and optimum connections design are proposed to reduce the response of a floating beam system. The auxiliary beams can either be attached to the front end, the rear end, or both ends of the floating main beam. A parametric study is carried out to study the effects of the lengths and the flexural rigidities of the auxiliary beams as well as the rotational stiffnesses of the connections on the hydroelastic response of the main floating beam. The main objective in this part of the study is to find the appropriate properties of the auxiliary beams and the connections for effective reduction in the hydroelastic response of the main floating beam. For the second phase of the study, the hydroelastic response of large floating beam with multiple connections is investigated. The effects of the connections locations and the rotational stiffnesses on the hydroelastic response of the floating beams system are studied. The main objective in this part of the study is to find the optimum locations and rotational stiffnesses of the connections for minimum hydroelastic response of the interconnected floating beams system. Alternating variable method is adopted for the optimization procedure. As the third phase of the study, the hydroelastic response of floating articulated beams for wave energy converter is investigated. Here, instead of reducing the hydroelastic response, we maximize the hydroelastic response in order to maximize the floating beams wave energy capturing efficiency by optimizing the connections design (i.e. the number of connections, the rotational stiffnesses, and the locations). Similar to the second phase of the study, alternating variable method is adopted for the optimization procedure.
URI: http://scholarbank.nus.edu.sg/handle/10635/17323
Appears in Collections:Ph.D Theses (Open)

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