Determination Of Local Electrical Impedance By The Resolution Of An Inverse Problem With The Boundary Element Method
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A numerical methodology is implemented for determining the local impedance of electrodes/material systems. Global electrical measurements obtained by Impedance Spectroscopy (IS) provide sufficiently reliable experimental data to evaluate internal properties by processing an inverse problem. In this approach, the complex potential equation in Alternative Current (AC) is solved using the Boundary Element Method and an inverse algorithm is then implemented for the determination of the local material and contact impedance from the global IS measurements. The proposed numerical method is tested in a theoretical electrodes/material system and for studying the response of an actual metal/stone interface. The latter electro-physic system which includes silver electrodes (conductive varnish) glued on a prismatic calcareous stone sample has been first analysed with a RLC bridge. From these experimental data, the inverse algorithm is applied successfully to characterise separately the interface and bulk material IS responses.