摘要
研究三维黏弹性薄板中激光激发兰姆波的传播特征。从应力-应变关系理论出发,推导出三维频域波动平衡方程。考虑材料的黏弹性特性,在频域内建立激光激发兰姆波的三维有限元模型,模拟三维黏弹性薄板中兰姆波的激光激发及其传播过程,数值结果与解析法计算所得的群速度曲线、色散曲线及衰减曲线特征完全一致。结果表明,在单向纤维黏弹性薄板中,随着垂直于纤维方向逐渐向平行于纤维方向转变,s0模和a0模的传播速度逐渐增大,a0模的色散特征逐渐减弱;兰姆波在同一方向的传播距离越远,波的衰减越大,且兰姆波中高频成分的衰减大于低频成分。
The propagation characteristics of laser-generated Lamb wave in the three-dimensional thin viscoelastic plate are studied.Based on the theory of the stress-strain relation,the three-dimensional equation of dynamic equilibrium in the frequency domain is derived.Taking account of the viscoelastic property of the material,the three-dimensional model of laser-generated Lamb wave in the frequency domain is established by the finite element method.The process of laser-generated Lamb wave and its propagation are simulated in the three-dimensional thin viscoelastic plate.The numerical results coincide well with the characteristics of the group velocity curve,dispersion curve and attenuation curve which calculated by the analytical method.The results show that the velocities of the s0 and a0 modes increase gradually and the dispersive nature of the a0 mode decreases with the direction normal to the fiber direction gradually turning to the direction along the fiber direction in the unidirectional fiber-reinforced thin viscoelastic plate.In addition,the increase of source-receiver distance along the same direction causes a marked increase in the attenuation of Lamb waves and the attenuation of the higher-frequency signal is stronger than the lower-frequency one.
出处
《激光与光电子学进展》
CSCD
北大核心
2010年第12期86-93,共8页
Laser & Optoelectronics Progress
基金
江苏大学百项本科生创新计划(2010074)
江苏大学学生科研立项(09A101)资助课题
关键词
光计算
激光超声
兰姆波
三维有限元
黏弹性
optics in computing
laser ultrasonic
Lamb wave
three-dimensional finite element
viscoelasticity
