Two-Dimensional Finite Element Simulation of Induction Thermography of an Aluminum Alloy Panel

Induction heating is the process of heating an electrically conducting object by electromagnetic induction, where eddy currents are generated within the test piece and electrical resistance leads to Joule heating of the test... [ view full abstract ]

Induction heating is the process of heating an electrically conducting object by electromagnetic induction, where eddy currents are generated within the test piece and electrical resistance leads to Joule heating of the test piece. Unlike typical eddy current inspections, this technique is not sensitive to crack orientation or part geometry and has potentials to improve the inspection speed and ease the visualization of flaw detection in complex geometries. To efficiently apply this technique, numerical analysis is needed to choose proper coil shape for generating practical heat distribution.
In this study, numerical simulations and non-destructive evaluation (NDE) techniques for inductive heating of a 5 mm thick 7075 aluminum alloy panel are presented. A two-dimensional axis-symmetric finite element model was developed using COMSOL multiphysics software version 4. The panel was approximated by a disk with 0.1 m diameter. In the experimental test, a 5 mm thick 7075-T6 aluminum alloy panel with dimension of 100x250 mm was heated using a copper coil with 3 loops in 50 mm external diameter. The alternative current used was 100 A with 200 kHz frequency. An infrared camera system was used to capture the panel temperature variation. The 2D axis-symmetric FE model meshed in two conditions and the temperature prediction profiles are shown in Fig. 1. Results showed that the influence of the mesh condition on the temperature was limited, and good agreement was obtained between experimental results and the FE predictions. The impact of the inductor (coil) location, current level, and panel size on the temperature profile are also investigated using the FE model. This parametric study is to determine the parameters that significantly influence the temperature profile. Future plan is to develop 3D FE models to further support the development of induction thermography technique and procedures for damage detection.
Keywords: Finite element; Induction heating; Multiphysics; Temperature.