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Journal of Sensors
Volume 2018 (2018), Article ID 1745257, 11 pages
https://doi.org/10.1155/2018/1745257
Research Article

Nonlinear Electromagnetic Acoustic Testing Method for Tensile Damage Evaluation

1School of Electrical and Automation Engineering, East China Jiaotong University, Nanchang 330013, China
2State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China

Correspondence should be addressed to Zhichao Cai; moc.liamxof@tubehczc

Received 19 July 2017; Accepted 26 December 2017; Published 10 April 2018

Academic Editor: Emad Elbeltagi

Copyright © 2018 Zhichao Cai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper describes an approach for measuring material plasticity using contactless electromagnetic acoustic method. Harmonic generation from noncumulative fundamental longitudinal wave in specimen is studied based on numerical method, and the contribution to harmonic generation from tensile damage is shown to be higher than that from a geometric factor; more serious damages increase the amplitude of second harmonics. These two experimental setups (nonlinear piezoelectric method and nonlinear electromagnetic acoustic method) are used to assess the relative nonlinearity parameters of tensile damage of five aluminum alloy specimens along the thickness direction, and the proposed technique is as effective with the traditional nonlinear piezoelectric method. This result demonstrates that the ultrasonic nonlinear parameter can represent tensile damage with ultrasonic nonlinear parameter by noncontact electromagnetic acoustic method.