Interaction of Lamb Wave Modes with Weak Material Nonlinearity: Generation of Symmetric Zero-Frequency Mode

Xiaoqiang Sun; Xiangyan Ding; Feilong Li; Shijie Zhou; Yaolu Liu; Ning Hu; Zhongqing Su; Youxuan Zhao; Jun Zhang; Mingxi Deng

doi:10.3390/s18082451

Interaction of Lamb Wave Modes with Weak Material Nonlinearity: Generation of Symmetric Zero-Frequency Mode

Sensors (Basel). 2018 Jul 28;18(8):2451. doi: 10.3390/s18082451.

Authors

Xiaoqiang Sun¹, Xiangyan Ding², Feilong Li³, Shijie Zhou⁴, Yaolu Liu⁵, Ning Hu^{6

7}, Zhongqing Su⁸, Youxuan Zhao⁹, Jun Zhang¹⁰, Mingxi Deng¹¹

Affiliations

¹ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. Tiny_Strong@sina.com.
² College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. dingxiangyan@cqu.edu.cn.
³ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. feilong.li@cqu.edu.cn.
⁴ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. m18716480894@163.com.
⁵ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. liuyaolu@cqu.edu.cn.
⁶ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. ninghu@cqu.edu.cn.
⁷ Key Disciplines Lab of Novel Micro-nano Devices and System, International R & D Center of Micro-nano Systems and New Materials Technology, Chongqing University, Chongqing 400044, China. ninghu@cqu.edu.cn.
⁸ Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China. youxuan.zhao@cqu.edu.cn.
⁹ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. mejzhang@cqu.edu.cn.
¹⁰ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. dengmx65@yahoo.com.
¹¹ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. zhongqing.su@polyu.edu.hk.

Abstract

The symmetric zero-frequency mode induced by weak material nonlinearity during Lamb wave propagation is explored for the first time. We theoretically confirm that, unlike the second harmonic, phase-velocity matching is not required to generate the zero-frequency mode and its signal is stronger than those of the nonlinear harmonics conventionally used, for example, the second harmonic. Experimental and numerical verifications of this theoretical analysis are conducted for the primary S₀ mode wave propagating in an aluminum plate. The existence of a symmetric zero-frequency mode is of great significance, probably triggering a revolutionary progress in the field of non-destructive evaluation and structural health monitoring of the early-stage material nonlinearity based on the ultrasonic Lamb waves.

Keywords: nonlinear Lamb waves; structural health monitoring; zero-frequency mode.