Method for forecasting vibration characteristics of cavity-containing composite material soft sandwich structure in fluid

Abstract

The invention belongs to the technical field of composite material vibration, and particularly discloses a method for forecasting vibration characteristics of an underwater cavity-containing compositematerial soft sandwich structure. The method comprises the following steps: enabling a soft sandwich structure forming the cavity-containing composite material soft sandwich structure to be equivalent to an orthotropic homogeneous material, and constructing a motion equation set of the sandwich structure in a vacuum condition; reconstructing the motion equation of the sandwich structure containing the homogeneous soft sandwich in the fluid along the thickness direction according to the radiation sound field and the fluid-solid coupling condition of the sandwich structure containing the homogeneous soft sandwich, so as to reconstruct the motion equation set; calculating the natural vibration and forced vibration response of the sandwich structure containing the homogeneous soft sandwich according to the obtained motion equation set, and taking the natural vibration and forced vibration response as the vibration characteristic of the composite material soft sandwich structure containingthe cavity in the forecast fluid. According to the method, the precision of calculating the vibration characteristics of the composite material soft sandwich structure is improved, the equivalent problem of the sandwich structure containing various cavity inclusions can be solved, and the application range is wide.

Description

technical field [0001] The invention belongs to the technical field of composite material vibration, and more specifically relates to a method for predicting the vibration characteristics of a cavity-containing composite material soft sandwich structure in a fluid. Background technique [0002] With the rapid development of sonar technology, modern ships have higher and higher requirements for acoustic stealth performance. In order to reduce the radiated noise and acoustic target intensity of the ship, the composite material acoustic structure with better acoustic performance is gradually applied to the ship structure. The cavity-containing composite soft sandwich structure is a kind of composite acoustic structure with good application prospects. Its soft core is a viscoelastic rubber material with a large loss factor, which can achieve vibration and sound absorption by using the shear energy dissipation mechanism; the periodically distributed cavities in the core can play...

AI Technical Summary

Problems solved by technology

At present, for the vibration characteristics of composite sandwich structures, the equivalent single-layer plate theory is the most commonly used research method, but this method has a large error when dealing with soft sandwich problems

At the same time, the vibration analysis of related composite material sandwich structures is mainly concentrated in the air, and the research in water is more difficult due to the complex fluid-solid interaction problems involved.

The finite element method can deal with the underwater vibration of composite soft sandwich structures, but modeling the flow field requires a large number of meshes and consumes a lot of computing resources and time, which is not conducive to the study of characteristics

In addition, the periodically distributed cavities in the core complicate the underwater vibration study of the structure

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