摘要
应用有限元方法研究了含非均匀介质层的复合薄层结构中的低频（0-2 kHz）声反射特性,其中非均匀介质层为橡胶中周期分布的多孔介质体.文中将流体等效处理为（粘）弹性体;对多孔介质,提出在薄层、低频下忽略其骨架的运动,由Biot理论获得退化的孔中流体的基本方程,并将其等效处理为（粘）弹性体;利用Galerkin方法建立了有限元方程,分析了非均匀层中多孔介质的体积分数,孔中流体材料参数、层厚度及多层非均匀介质的不同叠合对其结构反射特性的影响.结果表明,一定条件下含多孔介质的非均匀层可明显影响结构较低频段的反射系数.
A finite element method was applied to analyze the sound characteristics of thin layered acoustic structures containing fluid layer, elastic layer and viscoelastic layer with periodic porous medium, at low frequency （0-2 kHz）. It is considered that the fluid can be modeled as a viscoelastic medium with equiva- lent Lame constant. In addition, for thin layer at low frequencies, the porous frame may be assumed as motionless. In this case, the reduced control equation of pore fluid in porous material is obtained by Blot＇s theory. Similarly, the pore fluid is also equivalent to an elastic medium. The finite element formulation is derived by using the Oalerkin technique. The influences of the fraction of porous medium, the material constants of pore fluid in porous medium of the inhomogeneous layer, the layer thick and different arrangements of inhomogeneous layers on the reflection characteristics of the structure were analyzed. The results show that the existence of inhomogeneous medium has obvious effect on the reflection coefficient of the structure at lower frequency.
出处
《上海交通大学学报》
EI
CAS
CSCD
北大核心
2007年第6期1012-1016,共5页
Journal of Shanghai Jiaotong University
基金
国家自然科学基金项目资助(10572089)
关键词
多孔介质
层状声学结构
反射系数
porous medium
thin layered acoustic structure
reflection coefficient
