title: Mode Conversion Behavior of Guided Wave in a Pipe Inspection System Based on a Long Waveguide.
abstract: To make clear the mode conversion behavior of S0-mode lamb wave and SH0-plate wave converting to the longitudinal mode guided wave and torsional mode guided wave in a pipe, respectively, the experiments were performed based on a previous built pipe inspection system. The pipe was wound with an L-shaped plate or a T-shaped plate as the waveguide, and the S0-wave and SH0-wave were excited separately in the waveguide. To carry out the objective, a meander-line coil electromagnetic acoustic transducer (EMAT) for S0-wave and a periodic permanent magnet (PPM) EMAT for SH0-wave were developed and optimized. Then, several comparison experiments were conducted to compare the efficiency of mode conversion. Experimental results showed that the T(0,1) mode, L(0,1) mode, and L(0,2) mode guided waves can be successfully detected when converted from the S0-wave or SH0-wave with different shaped waveguides. It can also be inferred that the S0-wave has a better ability to convert to the T(0,1) mode, while the SH0-wave is easier to convert to the L(0,1) mode and L(0,2) mode, and the L-shaped waveguide has a better efficiency than T-shaped waveguide.
authors: Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China. sfr13@mails.tsinghua.edu.cn.
authors: Feiran
authors: F
authors: Sun
authors: Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China. sunzhg@tsinghua.edu.cn.|Yangtze Delta Region Institute of Tsinghua University, Jiaxing 314006, China. sunzhg@tsinghua.edu.cn.
authors: Zhenguo
authors: Z
authors: Sun
authors: Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China. chenq@tsinghua.edu.cn.|Yangtze Delta Region Institute of Tsinghua University, Jiaxing 314006, China. chenq@tsinghua.edu.cn.
authors: Qiang
authors: Q
authors: Chen
authors: Department of Intelligent Mechanical Engineering, Fukuoka Institute of Technology, Fukuoka 811-0295, Japan. murayama@fit.ac.jp.
authors: Riichi
authors: R
authors: Murayama
authors: Graduate School of Advanced Technology and Science, Tokushima University, Minami-Josanjima, Tokushima 770-8506, Japan. hidero.nishino@tokushima-u.ac.jp.
authors: Hideo
authors: H
authors: Nishino
keywords: EMAT; guided wave; mode conversion; pipe inspection; waveguide