Study of eddy currents non destructive testing system in riveted assemblies

Abstract

In order to optimize eddy current sensors, we have to simulate electromagnetic phenomena to predict sensors' response. 2D and 3D codes can be used but what kind of result can be expected from each of these codes? In this paper, performances of 3D formulations are tested using FEM package Flux3d. Adapted coupled formulations and boundary conditions are used to study eddy currents perturbation by flaws in aircraft riveted assemblies. Physical informations about the influence of flaw depth are obtained. The 3D calculations allow us to choose the most adapted measurement quantity and to define the position of the measurement sensors. Then, for optimizing the sensor, 2D FEM package Fissure is used taking into account the 3D results.

An NDT Pulse Shape Study With TEAM Problem 27

“…For a square flaw the signal is sensitive to changes in both width and height, thus contrary to the experimental results, the square flaw is expected to have a larger signal than either the horizontal or vertical flaws. This conclusion is supported by the results reported in [2], which performed time harmonic analyses of different flaws at 500 Hz. As shown in [2, Fig.…”

“…Previous work on this problem calculated differential flux densities horizontally and vertically for various size flaws, but using a sinusoidal excitation [2]. Other work also included the design of a genetic optimization algorithm to design a well adapted sensor [3].…”

Numerical and Experimental Study of Eddy Current Crack Detection around Fasteners in Multi-Layer Structures

“…The boundary element method and volume integral method are generally the most efficient, but have difficulty handling very complicated geometries. The particular problem of cracks around fasteners in multilayer structures has been modeled using the finite element method and boundary element method [1,[7][8][9][10]. Beissner used finite element simulations to study the difference between segment and cup core configurations of the probe.…”

Computing methods of hypersingular integral applied to eddy-current testing

“…Numerical methods to solve Maxwell's equations are required to evaluate this perturbation. The field computation is fully three-dimensional (3-D) and reveals important variations of the electromagnetic field near crack [1].…”