复合材料黏弹性对超声传播影响的研究

Research on Effect of Composite Material Viscoelasticity on Ultrasonic Propagation

采用激光超声无损检测设备,凭借其信噪比高、频带宽与非接触的特点,针对市面上两种不同复合材料成型工艺,将材料黏弹性参数考虑进超声仿真的数值模拟中,得到了声波在复合材料中传播的位移云图与透射纵波位移图;比较了超声在2种成型工艺的复合材料中的传播特性,同时采用谱方法与有限元方法相结合,将波动方程变换到频域中进行求解,得到激光超声在2种工艺下传播的相速度曲线图。结果证明,超声在经过胶粘层时,黏弹性会导致声波色散,从而导致声波振幅的降低,黏弹性是复合材料激光超声检测中不得不考虑的一个重要因素。

Laser ultrasonic nondestructive testing equipment is used.With its high signal-to-noise ratio,frequency bandwidth and non-contact characteristics,for two different composite material molding processes on the market,the material viscoelastic parameters are taken into account in the numerical simulation of ultrasonic simulation.Displacement cloud image of sound wave propagating in composite material and displacement image of transmitted longitudinal wave are obtained;the propagation characteristics of ultrasound in the composite materials of two different molding processes are compared.Meanwhile,the spectral method is combined with the finite element method to transform the wave equation into the frequency domain for solution,and the phase velocity curve of propagation of laser ultrasound under two different processes is obtained.The results prove that when ultrasound passes through the adhesive layer,the viscoelasticity will cause the dispersion of the acoustic wave,which leads to the reduction of the acoustic wave amplitude.Viscoelasticity is an important factor that has to be considered in the laser ultrasonic inspection of composite materials.