Affiliations: Shaanxi Engineering Research Center for NDT and Structural Integrity Evaluation, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an, Shaanxi, China
Correspondence:
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Corresponding author: Zhenmao Chen, Shaanxi Engineering Research Center for NDT and Structural Integrity Evaluation, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, 28 West Xianning Road, Xi'an 710049, Shaanxi, China. Tel./Fax: +86 29 82668736; E-mail:chenzm@mail.xjtu.edu.cn
Abstract: In this study, the strategy to simulate a real stress
corrosion crack (SCC) with a closed fatigue crack (FC) in view of eddy
current testing (ECT) is investigated. An online four-point bending ECT
device is designed and fabricated to provide the closure loading for a plate
specimen and to enable online ECT measurements. The amplitudes of ECT
signals due to FCs closed with different closure loads are measured. The
experimental results show that the amplitudes of ECT signals due to closed
FCs change regularly with the applied closure loads, and the ECT signal will
recover to the initial state once the closure loading is released. The
experimental results also reveal that, instead of the residual plastic
strain, the online closure loading can make the FC conductive and a larger
load leads to bigger crack conductivity. Through inverse analysis of the
measured ECT signals, it is found that the conductivity in the crack region
can reach to as big as 45% of the base material conductivity due to a
large closure load. The results of this work demonstrated the feasibility
positively to simulate a SCC with an online closed FC specimen for ECT
measurement.
