Finite Element Analysis of Eddy Current Testing of Aluminum Honeycomb Sandwich Structure with CFRP Panels Based on the Domain Decomposition Method

Aluminum honeycomb sandwich structure with panels made of carbon fiber reinforced polymer (CFRP) are widely used in aerospace and other fields. Simulation of the eddy current (EC) testing of the sandwich structure using the finite element (FE) method is challenging as the traditional FE method has difficulties in mesh division and the solution of the algebraic equations. This paper proposes to use the domain decomposition FE method to solve such problems. The top CFRP panel, the aluminum honeycomb core, and the bottom CFRP panel of the sandwich structure and the ferrite core of the coil are placed in different subdomains and the subdomains are meshed independently. This method simplifies the mesh generation and does not require regenerating the meshes when simulating the scanning testing with the ferrite-core coil. In this way, the efficiency of simulation is greatly improved. The EC distributions in the sandwich structure are computed and the influence of defect on EC distribution is analyzed. The C scans of the sandwich structures are simulated. The images of the EC responses to the defects, such as wall fracture, node disconnection, and core wrinkle, are obtained. The simulation results are validated by experiments.