Lift-Off Effect of Koch and Circular Differential Pickup Eddy Current Probes

作     者：Guolong Chen Zheng Cao Shuaishuai Zhang Ji Wei Wei Gao Wuyin Jin Guolong Chen;Zheng Cao;Shuaishuai Zhang;Ji Wei;Wei Gao;Wuyin Jin

作者机构：School of Mechanical and Electrical EngineeringLanzhou University of TechnologyLanzhou 730050China 

出 版 物：《Chinese Journal of Mechanical Engineering》 (中国机械工程学报（英文版）)

年 卷 期：2024年第37卷第2期

页      面：283-293页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 0701[理学-数学] 080201[工学-机械制造及其自动化] 

基　　金：Supported by Gansu Provincial Natural Science Foundation of China(Grant No.22JR5RA229) National Natural Science Foundation of China(Grant Nos.51807086,12162021) Hongliu Youth Found of Lanzhou University of Technology and Gansu Provincial Outstanding Graduate Student Innovation Star of China(Grant No.2021CXZX-453) 

主　　题：Eddy current testing Differential pickup probe Fractal Koch curve Flexible eddy current probe 

摘      要：A flexible or planar eddy current probe with a differential structure can suppress the lift-off noise during the inspection of ***,the extent of the lift-off effect on differential probes,including different coil structures,*** this study,two planar eddy current probes with differential pickup structures and the same size,Koch and circular probes,were used to compare lift-off *** eddy current distributions of the probes perturbed by 0°and 90°cracks were obtained by finite element *** analysis results show that the 90°crack can impede the eddy current induced by the Koch probe even further at relatively low lift-off *** peak-to-peak values of the signal output from the two probes were compared at different lift-off distances using finite element analysis and experimental *** addition,the effects of different frequencies on the lift-off were studied *** results show that the signal peak-to-peak value of the Koch probe for the inspection of cracks in 90°orientation is larger than that of the circular probe when the lift-off distance is smaller than 1.2 *** addition,the influence of the lift-off distance on the peak-to-peak signal value of the two probes was studied via *** indicates that the influence becomes more evident with an increase in excitation *** research discloses the lift-off effect of differential planar eddy current probes with different coil shapes and proves the detection merit of the Koch probe for 90°cracks at low lift-off distances.