ROTATING ELECTROMAGNETIC FIELD FOR NDT INSPECTIONS
Reliable performance of a component or structure depends on its pre-service quality and in-service degradation under operating conditions. The importance of Non-Destructive Testing and Evaluation is ever increasing, above all in ensuring pre-service quality and monitoring in-service degradation, in order to avoid premature failure of the components/structures. There are many Non-Destructive Techniques based on various physical principles. In this work, our main objective is the characterization of anomalies such as defects, stresses and microstructural degradations in materials. Particularly, in this work we propose a Finite Element Method based approach for modelling a fast and accurate evaluation of defects in metallic materials able to easily detect defects, aside from the orientation. Within this framework, the paper proposes the application of a magnetic fleld rotating perpendicularly to the analysed specimen. We discuss a few case studies, starting from numerical simulations and flnally highlighting the importance of this approach in order to evaluate the structural integrity assessment.
Analytical modeling of an inductive sensor with open magnetic core and conductive shielding above a multi-layered medium
Inductive sensors are used to detect or test magnetic and/or conductive targets. In this paper, a simplified analytical modeling of an inductive sensor having a magnetic core and a conductive shielding is presented with an inspected target consisting in a stratified medium. Two shapes of magnetic core geometries are considered: cup-core and U-core. Comparisons of results obtained using the analytical model with numerical and experimental data show a quite good agreement in spite of the modeling assumptions.
Geometric Interpretation of Discrete Approaches to Solving Magnetostatics
The finite element approach can be considered as a tool for constructing finite dimensional systems of equations that approximate to field problems on the discrete level. Although the finite element technique is explained typically in terms of variational or weighted-residual approaches, another, less familiar way is available to introduce the same ideasgeometrically. Using magnetostatics as an example, we will show how finite element type system matrices can be developed by exploiting the geometric properties of so calledWhitney elements . The simple interpretation we gain thereby enables us to view also the convergence properties of finite element type schemes in an intuitive way.