无限液体介质内管道轴对称纵向导波激发与传播特性研究  

Excitation and propagation of axisymmetric longitudinal guided waves in pipes immersed in infinite liquid media

作　　者：刘胜兴[1,2] 汤立国[1,2] 许肖梅[1,2] 

机构地区：[1]厦门大学海洋学系,厦门361005 [2]厦门大学水声通信与海洋信息技术教育部重点实验室,厦门361005

出　　处：《声学学报》2009年第4期334-341,共8页Acta Acustica

基　　金：国家自然科学基金(10704064;40776022);福建省自然科学基金(D0810027)资助项目

摘　　要：利用声-结构耦合有限元法,分别对轴对称分布径的向及轴向外力作用在无限液体介质内未充液及充液管道内壁所激发导波进行了模拟,并进一步利用短时傅里叶变换技术对瞬态波形作时频分析,在此基础上,结合色散及衰减曲线,探讨了外力分布特征对导波激发的影响。研究表明,无限液体介质内未充液管中L(0,2)模式及充液管中L(0,3)～L(0,4)模式皆具有高群速度、弱色散且弱衰减频带,适宜用于缺陷探测,而通过控制轴对称分布外力的频率,并令其沿轴向作用于管内壁或外壁,可实现上述导波模式的高效激发。The transient elastodynamic responses of the vacuum and liquid-filled pipes surrounded by infinite liquid to axisymmetric external forces are simulated by the acoustic-structural coupled finite element method. The time-frequency distributions of the transients waveforms are obtained by the short-time Fourier transform（STFT）. The influence of the distribution of the external forces on the excitation of the guided waves is analyzed based on the above results and dispersion and attenuation curves. The study shows that the L（0, 2） mode in the vacuum pipe surrounded by the liquid is suitable to be employed for the pipe inspection because it is the fastest mode in a weakly dispersive and attenuative region of frequency. And it can be excited high efficiently in the above region of frequency if the axisymmetric external force is applied on the inner or outer surface of the pipe axially. Analogously, the L（0, 3） and L（0, 4） modes in the liquid-filled pipe surrounded by the liquid are suitable for the pipe inspection.

关 键 词：轴对称分布 导波模式 液体介质 管道内壁 激发 传播特性 衰减曲线 有限元法 

分 类 号：TB55[理学—物理]