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Date of Publication:2005-01-01

Journal:船舶力学

Issue:2

Page Number:115-123

ISSN No.:1007-7294

Abstract:In the framework of linear sound theory, the inherence acoustic radiation properties of a structure are fully described by its acoustic radiation modes. In this paper, the radiation modes of a stiffened panel under different damaged conditions are 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 natural frequencies, vibration and acoustic radiation modes are studied. A computational method is given, aided by some typical examples, to analyze acoustic behavior of a damaged structure. Panels are widely-used ship and ocean structures. The current method is useful for assessing the influences of the damages present in a stiffened panel on its acoustic radiation properties.

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