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Date of Publication:2007-01-01

Journal:船舶力学

Issue:4

Page Number:628-636

ISSN No.:1007-7294

Abstract:In the framework of energy dissipation theory, radiation damping of structural sound is proposed. Using the ratio between the dissipated energy and the total energy of a vibrating structure to account for the characteristics of radiation damping, a mathematical model for radiation damping is built. Based on the mathematical model, the radiation damping of a simply supported plate is calculated. The radiation damping of a stiffened plate under different damaged conditions is also investigated. Based on Mindlin theory, four-node health and damage shell finite elements are given, and then the finite element method is used to calculate the dynamic surface response of a structure. Isotropic damage elements are built by globally and isotropically weakening the stiffness. Anisotropic damage elements are built by using reduction coefficients for elasticity damages in x and y directions based on Kachanov's theory. Influences of various types of damages on acoustic radiation damping are studied. A computational method is established, aided by some typical examples, to analyze acoustic behavior of a damaged structure. Plates are widely-used in ship and ocean structures. The current method is useful for assessing the, influences of the damages present in a stiffened plate on its acoustic radiation properties.

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