Numerical Modelling of Eddy Current Non- Destructive Evaluation by Integral Formulation and Parallel Implementation * Ermanno CARDELLI, Antonio FABA Department of Industrial Engineering, University of Perugia, Perugia, Italy. Raffaele FRESA, Salvatore VENTRE DIFA, University of Basilicata, Potenza, Italy. DAEIMI University of Cassino, Cassino, Italy. Abstract. In this paper we present some results drawn from a research project of national interest named MADEND (Methods and Applications of Non-destructive Electromagnetic Diagnostic). In particular we show a comparison between two numerical models: eddy current integral formulation on parallel computer systems and differential formulation of finite element method. The numerical results and accuracy are confirmed by experimental tests. 1. Introduction In Italy, since January 2002, some University research groups have been working on a so called “Project of Remarkable National Interest” of the National Italian Ministry of Education about methods and applications of electromagnetic diagnostic based on eddy current phenomena. The name of the project is MADEND and its purpose is to present and to develop the research possibilities in this field. Some results dealing with the MADEND programme are reported in this paper. In particular we present here a numerical model based on integral formulation and parallel implementation that allows a great saving of calculation time with respect to traditional numerical models. The benchmarks defined for this comparison are the MADEND benchmarks # 1, 2 and 3. The benchmark #1 is an aluminium plate with a thickness of 4 mm. On this plate there is an artificial defect with cylindrical shape, with a diameter of 1 mm and a height of 4 mm, (reduced respectively to 3mm and 2 mm for the benchmarks #2 and #3). The used probe is a coil placed on the metallic surface under test. For the benchmark # 2 and 3 the probe coil is placed on the opposite side with respect to the cylindrical defect. This coil is electrically linked to a suitable balanced bridge circuit and the voltage variation on the bridge allows the crack identification. 2. Integral formulation and parallel implementation Integral formulation The design and the analysis phases of modern devices for engineering applications, including among others the electromagnetic non-destructive evaluation, require accurate numerical solutions of Maxwell equations in the Quasi Stationary Magnetic limit. In the last decades many scientists focused their research activity on this topic. In the usual classification the * This work has been supported by the Italian Ministry of Education (MIUR, Project MADEND) and EURATOM/ENEA/CREATE.