An Eddy Current Nondestructive Method for Crack Detection in Multilayer Riveted Structures

Abstract

It is a challenging task to detect the hidden cracks in multilayer riveted structures in a nondestructive manner. This paper puts forward an eddy current nondestructive method for crack detection in such structures based on the electric conductivity of the rivets. Specifically, an eddy current sensor was designed with a ferrite core coil to evaluate the surface and inner defects of different layers. The magnetic phenomena during the detection process was simulated based on the magnetic potential and the scalar electrical potential, and the magnetic potential vector was solved by finite-element method. The proposed method was compared with the eddy current detection method without considering rivet conductivity through an experiment on a three-layer riveted aluminum structure. The length and position of each defect on each layer were changed in the experiment. The results show that the proposed method achieved better accuracy than the contrastive method, and its sensitivity depends on two issues: the position of the defect relative to the separation of the layers and the length of the defect relative to the length of the rivet head. The research results are of great significance for nondestructive testing of multilayer riveted structures in many fields.

Non-destructive rapid defect testing around curved head rivets without displacement of eddy current sensors

“…Countersunk rivets are commonly used in aeronautics to assemble multi-layer structures due to their strength and ability to maintain the structural integrity of aircraft. However, inspecting these assembly areas can be challenging due to the opacity of the rivets and the presence of multiple layers of materials (Abdou et al (2019); Janovec et al (2019a)).…”

Extended Damage Detection and Identification in Aircraft Structure Based on Multifrequency Eddy Current Method and Mutual Image Similarity Assessment

“…According to the industry survey of structural health monitoring technology and NDT usage [ 9 ], crack detection is one of the most essential and current aerospace industry needs in implementing the NDT and Structural Health Monitoring (SHM) systems. The most problematic are inspections of multilayer riveted structures for detecting fatigue cracks propagating from the rivet hole, especially in lower layers [ 10 ]. For such structures, the crack size and depth determination are crucial issues from the detection accuracy point of view.…”