Applied modeling and inverse profiling in electromagnetic non-destructive evaluation

This paper presents three examples of applied numerical modeling and inverse profiling in electromagnetic non-destructive testing. In the first example, we discuss numerical modeling and optimization of eddy current sensors for in-line inspection of hot wire steel. To detect longitudinal cracks a series of new sensors are modelled and optimized by numerical modeling and is successfully tested. The second example presents the application of a time-domain technique to reconstruct the unknown permittivity and electric conductivity profile of a one-dimensional slab of finite length. The inverse scattering problem is solved by an Invariant Embedding Method which requires a finite time trace of reflection data and therefore is suitable for reconstructing the material parameters in real-time. The implemented method is validated against synthetic and measured Time Domain Reflectometry data. The third example demonstrates the application of the Contrast Source Inversion method to reconstruct the 2-D permittivity profile of a beech tree. Thus, the discussed applications present an identified need of numerical modeling and inverse profiling in electromagnetic non-destructive evaluation.