Laser-generated thermoelastic acoustic sources and acoustic waves in anisotropic plate  

作　　者：XU BaiQiang WANG Feng FENG Jun WANG JiJun SUN HongXiang LUO Ying 

机构地区：[1]Faculty of Science,Jiangsu University,Zhenjiang 212013,China

出　　处：《Science China(Technological Sciences)》2009年第3期566-574,共9页中国科学（技术科学英文版）

基　　金：Supported by the Natural Science Foundation of Jiangsu University (Grant No. 05JDG007);the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (Grant Nos. 08KJB140003 and 07KJB140019)

摘　　要：The effect of anisotropy on the ultrasound wave generation and propagation in the unidirectional fi- ber-reinforced composite plate has been investigated. A quantitative numerical model for the la- ser-generated ultrasound in the thermoelastic regime was presented by using a finite element method. All factors, such as spatial and time distributions of the incident laser beam, optical penetration, ther- mal diffusivity, and source-receiver distance can be taken into account. Numerical results show that the effect on ultrasound waveform of the size of the laser volume source produces strong bipolar longitu- dinal waves and improves the amplitude and directivity of the longitudinal waves. A fiber-reinforced composite material exhibits isotropic or homogenous behavior for ultrasonic wave propagation per- pendicular to the fiber direction. For ultrasonic propagation along the fiber direction, ultrasonic dis- persion resulting from the inhomogeneous nature of the material affects the laser ultrasonic waveforms. As the dimensions of the laser pulse are increased in space and time, the displacement waveform be- comes broader and its magnitude decreases.The effect of anisotropy on the ultrasound wave generation and propagation in the unidirectional fiber-reinforced composite plate has been investigated. A quantitative numerical model for the laser-generated ultrasound in the thermoelastic regime was presented by using a finite element method. All factors, such as spatial and time distributions of the incident laser beam, optical penetration, thermal diffusivity, and source-receiver distance can be taken into account. Numerical results show that the effect on ultrasound waveform of the size of the laser volume source produces strong bipolar longitudinal waves and improves the amplitude and directivity of the longitudinal waves. A fiber-reinforced composite material exhibits isotropic or homogenous behavior for ultrasonic wave propagation perpendicular to the fiber direction. For ultrasonic propagation along the fiber direction, ultrasonic dispersion resulting from the inhomogeneous nature of the material affects the laser ultrasonic waveforms. As the dimensions of the laser pulse are increased in space and time, the displacement waveform becomes broader and its magnitude decreases.

关 键 词：LASER ultrasound numerical simulation ANISOTROPIC material 

分 类 号：TB52[理学—物理]