Extension of the Discrete-Module-finite-element Method into the Interconnected Large Floating Flexible Structures

The discrete-module-finite-element (DMFE) method has been proposed and well-developed to analyze the hydroelasticity of floating flexible structures, in which the structure is discretized into several macro-submodules (for hydrodynamic analysis) and each of them is further discretized with finite element (for consideration of deformation). The DMFE method omits the determination of optimal modal combination, which is sometimes difficult for the mode superposition method in analyzing floating structures with complex geometric features, and maintains greater computational efficiency over the direct method in analyzing floating structures with huge size. However, the previous study only focused on continuous structures. In the present paper, it is investigated in the framework of the DMFE method the hydroelasticity of interconnected floating structures, such as orthogonal hinges, arbitrary hinges, rotational springs and etc. Procedures to model the orthogonal hinge connections are given first to illustrate the strategy, that is, defining the stiffness matrix of the connector based on the constraint features of connection types and installing it into the overall stiffness matrix before deriving the lumped-mass stiffness matrix. Modelling of arbitrary hinges are presented with introduction of a transformation matrix, followed by illustration of complex interconnections. The method is verified through comparisons with numerical results from other scholars.