An extension of coupled beam method and its application to study ship's hull-superstructure interaction problems

Abstract

This paper describes an extended formulation for the coupled beam method (CBM). The method is originally developed for elastic bending response analysis of passenger ships with large multi-deck superstructures. The extension is mainly performed to enable the available method in order to study elastic bending behaviour of ships fitted with superstructures of any sizes and locations. Finite element method (FEM) is applied for solving the equilibrium equations. Both hull and superstructure of the ship are modelled using beam elements. The connection between beam elements representing hull and superstructure is made using specially developed spring box elements. The accuracy of the extended method is demonstrated using an available experimental result. Then, two simplified structures, one representing a ship with a short superstructure and the other one representing a ship with a long superstructure, are analysed in order to validate the extended coupled beam method against the finite element method. In spite of some existing simplifications in the extended formulation, it is very effective in the early stages of ship structural design owing to its advantageous capability of rapid estimation of the longitudinal stress distributions along the height of ships at different stations.

Novel equivalent function for deadzone nonlinearity: applied to analytical solution of beam vibration using He's Parameter Expanding Method

“…Recently, considerable attention has been directed towards analytical solutions for nonlinear equations without small parameters. Many new techniques have been appeared in the literature such as perturbation techniques [11,20,29], variational iteration method [6], iteration perturbation method [9], He's Improved Amplitude-Formulation (IAFF) [6], HAM [24], HPM [8], MHPM [18], Meshless analysis [14], Modified wave approach [2] and Min-Max method [5] are used to solve nonlinear problems. He's Parameter expanding method (HPEM) is the most effective and convenient method to analytically solve of nonlinear differential equations.…”