title: A Flexible Arrayed Eddy Current Sensor for Inspection of Hollow Axle Inner Surfaces.
abstract: A reliable and accurate inspection of the hollow axle inner surface is important for the safe operation of high-speed trains. In order to improve the reliability of the inspection, a flexible arrayed eddy current sensor for non-destructive testing of the hollow axle inner surface was designed, fabricated and characterized. The sensor, consisting of two excitation traces and 28 sensing traces, was developed by using the flexible printed circuit board (FPCB) technique to conform the geometric features of the inner surfaces of the hollow axles. The main innovative aspect of the sensor was the new arrangement of excitation/sensing traces to achieve a differential configuration. Finite element model was established to analyze sensor responses and to determine the optimal excitation frequency. Experimental validations were conducted on a specimen with several artificial defects. Results from experiments and simulations were consistent with each other, with the maximum relative error less than 4%. Both results proved that the sensor was capable of detecting longitudinal and transverse defects with the depth of 0.5 mm under the optimal excitation frequency of 0.9 MHz.
authors.affiliation: 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.forename: Zhenguo
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China. caid14@mails.tsinghua.edu.cn.
authors.forename: Dong
authors.initials: D
authors.lastname: Cai
authors.affiliation: Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China. zoucme@126.com.
authors.forename: Cheng
authors.initials: C
authors.lastname: Zou
authors.affiliation: Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China. wenzeng@tsinghua.edu.cn.
authors.forename: Wenzeng
authors.initials: W
authors.lastname: Zhang
authors.affiliation: 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.forename: Qiang
authors.initials: Q
authors.lastname: Chen
keywords: eddy current; flexible arrayed sensor; frequency optimization; hollow axle