Frequency analysis of finite steel cylinders and their comparison to complex cylinder-like targets using an electromagnetic induction sensor

This paper shows that the standard industrial targets that need to be detected using an electromagnetic induction sensor cannot be represented by their exact size definition in international standards. Reinforcing steel with defined 16mm diameter according to the DIN norm is analyzed using a finite element harmonic electromagnetic computational model. The response was compared to pure cylindrical shape targets in order to find the correction in a diameter that needs to be used instead. The complex-shaped target of defined standard diameter must be modeled using larger diameter when using perfectly round cylinders in computational models depending on the frequency used and depth of this target.