中国物理B ›› 2007, Vol. 16 ›› Issue (4): 1062-1071.doi: 10.1088/1009-1963/16/4/034

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Mechanism of the excitation of single pure mode L(0, 2) and its interaction with the defect in a hollow cylinder

汤立国1, 许肖梅1, 程建春2   

  1. (1)Department of Oceanography, Xiamen University, Xiamen 361005, China sjb)Key Laboratory of Underwater Acoustic Communication and Marine Information Technology, Ministry of Education, Xiamen University, Xiamen 361005, China; (2)Laboratory of Modern Acoustics and Institute of Acoustics, Nanjing University, Nanjing 210093, China
  • 收稿日期:2006-09-13 修回日期:2006-11-07 出版日期:2007-04-20 发布日期:2007-04-20
  • 基金资助:
    Project supported by the Research Startup Fund for New Research Staff of Xiamen University, China.

Mechanism of the excitation of single pure mode L(0, 2) and its interaction with the defect in a hollow cylinder

Tang Li-Guo(汤立国)a)b)†, Cheng Jian-Chun(程建春)c)‡, and Xu Xiao-Mei(许肖梅)a)b)   

  1. a Department of Oceanography, Xiamen University, Xiamen 361005, China; b Key Laboratory of Underwater Acoustic Communication and Marine Information Technology, Ministry of Education, Xiamen University, Xiamen 361005, China; b Laboratory of Modern Acoustics and Institute of Acoustics, Nanjing University, Nanjing 210093, China
  • Received:2006-09-13 Revised:2006-11-07 Online:2007-04-20 Published:2007-04-20
  • Supported by:
    Project supported by the Research Startup Fund for New Research Staff of Xiamen University, China.

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摘要： Guided elastic waves have a great potential in pipe inspection as an efficient and low-cost nondestructive evaluation (NDE) technique, among which the wave of mode L(0,2) receives a lot of attention because this mode is the fastest mode in a weakly dispersive region of frequency to minimize dispersion effects over a long distance and sensitive to the defects distributed circumferentially. Though many experimental and numerical researches have already been carried out about the excitation of L(0,2) and its interaction with the defect in a hollow cylinder, its excitation mechanism has not been clarified yet. In this paper based on the transient response solution of the hollow cylinder, derived by the method of eigenfunction expansion, the theory about the exciting mechanism of mode L(0,2) is advanced and the effects of the spatial distribution, vibration frequency and direction of the external force on the excitation are discussed. And the pure mode L(0,2) is excited successfully under the parameters obtained through theoretical analysis. Furthermore, its interactions with some kinds of defects in hollow cylinders are simulated with the method of finite element analysis (FEA) and the results agree well with those obtained by other researchers.

关键词: excitation, L(0, 2) mode, hollow cylinder, eigenfunction expansion

Abstract: Guided elastic waves have a great potential in pipe inspection as an efficient and low-cost nondestructive evaluation (NDE) technique, among which the wave of mode L(0,2) receives a lot of attention because this mode is the fastest mode in a weakly dispersive region of frequency to minimize dispersion effects over a long distance and sensitive to the defects distributed circumferentially. Though many experimental and numerical researches have already been carried out about the excitation of L(0,2) and its interaction with the defect in a hollow cylinder, its excitation mechanism has not been clarified yet. In this paper based on the transient response solution of the hollow cylinder, derived by the method of eigenfunction expansion, the theory about the exciting mechanism of mode L(0,2) is advanced and the effects of the spatial distribution, vibration frequency and direction of the external force on the excitation are discussed. And the pure mode L(0,2) is excited successfully under the parameters obtained through theoretical analysis. Furthermore, its interactions with some kinds of defects in hollow cylinders are simulated with the method of finite element analysis (FEA) and the results agree well with those obtained by other researchers.

Key words: excitation, L(0, 2) mode, hollow cylinder, eigenfunction expansion

中图分类号:  (Methods of materials testing and analysis)

  • 81.70.-q
46.40.Cd (Mechanical wave propagation (including diffraction, scattering, and dispersion))