Sound Radiation Analysis of Constrained Layer Damping Structures Based on Two-Level Optimization.

Zhang Zhang,Chen Chen,Wang Wang,Zheng Zheng,Wu Wu

doi:10.3390/ma12193053

Zhang Zhang, Chen Chen + Show 3 more

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https://doi.org/10.3390/ma12193053

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Abstract

Constrained layer damping (CLD) is an effective method for suppressing the vibration and sound radiation of lightweight structures. In this article, a two-level optimization approach is presented as a systematic methodology to design position layouts and thickness configurations of CLD materials for suppressing the sound power of vibrating structures. A two-level optimization model for the CLD structure is developed, considering sound radiation power as the objective function and different additional mass fractions as constraints. The proposed approach applies a modified bi-directional evolutionary structural optimization (BESO) method to obtain several optimal position layouts of CLD materials pasted on the base structure, and sound power sensitivity analysis is formulated based on sound radiation modes for the position optimization of CLD materials. Two strategies based on the distributions of average normalized elemental kinetic energy and strain energy of the base plate are proposed to divide optimal position layouts of CLD materials into several subareas, and a genetic algorithm (GA) is employed to optimally reconfigure the thicknesses of CLD materials in the subareas. Numerical examples are provided to illustrate the validity and efficiency of this approach. The sound radiation power radiated from the vibrating plate, which is treated with multiple position layouts and thickness reconfigurations of CLD materials, is emphatically discussed.

Highlights

Modern structures, involving thin plates and shell-type structures in vehicles, ships, and aerospace, are increasingly being made of lightweight materials due to the well-known social need for energy savings
It is very clear that the additional mass fraction ratios are not evenly spaced, which implies that removing solid Constrained layer damping (CLD) elements during an earlier stage of the optimization process plays a key role in suppressing the sound radiation power, and in contrast, recovering void elements during a later stage of optimization for improving the reduction of sound radiation power is very useful
This paper presents a systematic methodology for designing position layouts and thickness configurations of CLD materials for suppressing the sound power of vibrating structures

Summary

Introduction

Modern structures, involving thin plates and shell-type structures in vehicles, ships, and aerospace, are increasingly being made of lightweight materials due to the well-known social need for energy savings. Despite their superior structural characteristics, lightweight structures exhibit poor vibrational and acoustic isolation levels. Constrained layer damping (CLD) treatment for the base structure has been regarded as an effective way to suppress structural vibration and acoustic radiation since CLD treatment was proposed by Kerwin [1]. It is highly desirable to find the optimal configurations of CLD materials for the purpose of suppressing the vibration and sound radiation This raises the problem of design optimization of the CLD materials attached to a base structure

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