A Meshless Finite Element Method for Modelling Coils and Cracks to Simulate Eddy Current Testing.

Abstract

This paper presents work on a numerical simulation method for eddy current testing applied to the in-service inspection of steam generator tubes in nuclear power plants. When finite elements (FEs) are used to predict eddy current signals, test articles, coils, cracks and air must be modeled. Additionally, it is necessary to compute the eddy current signals with the coil motion. While an easy way might be to use boundary elements (BEs) or the FE-BE hybrid method, the matrices of algebraic equations arrived at by these methods become full populated. Realistic problems require the modelling of natural cracks with complex geometries such as stress corrosion cracks or intergranular attacks. In this paper governing equations for an eddy current field are introduced to represent the current sources without using finite elements to model the coils, and a meshless method is proposed for crack representation. Finally, the results of numerical simulation are compared with experimental measurements, followed by a numerical study to briefly consider the application of this approach to the natural cracks.