谱有限元模拟正交各向异性黏弹性材料中导波传播特性

研究了导波在正交各向异性黏弹性复合板中传播的色散特性、波结构及功率流密度。基于二维平面运动方程,采用谱有限元方法得到了导波色散的特征方程。分析了正交各向异性黏弹性板中各向异性和黏性对能量速度和波结构的影响,以及基底对导波功率流密度的影响。数值研究结果表明:导波沿纤维方向传播的能量速度大,材料的黏性对速度影响较小,但会减小波结构的幅度;在高频时,基底的存在使两个基本模态的功率流密度分别集中到波导的上下表面,形成弱色散、高衰减及无色散、零衰减的表面波。数值模拟结果为导波用于复合材料定量无损检测和性能评价提供理论依据。 

Spectral finite element modeling of characteristics of guided waves propagation in orthotropic viscoelastic material

The dispersion,the mode shape and the power flow density of guided waves in a orthotropic viscoelastic composite plates is studied.Based on two-dimensional eqquations of motion,the dispersion equation is obtained using spectral finite element method.The effect of anisotropy and viscosity to the energy velocity and the mode shape of guided waves have been studied in the orthotropic viscoelastic plate,as well as the effect of substrate to the power flow density of the guided waves has been analyzed.The results showed that the maximum energy velocity is obtained when the guided waves propagate along the fiber orientation;the viscosity of material has little effect on the velocity but decreases the amplitude of mode shape;due to the presence of substrate,the power flow density of two fundamental mode concentrates to the upper and lower surfaces of the waveguided in the high-frequency range,which form a weak dispersion,high attenuation and a non-dispersion,non-attenuation surface waves,respectively.The numerical result provides a theoretical basis of guided waves for quantitatively non-destructive testing and performance evaluation of composite materials.