Capacitive probe for non destructive inspection of external post-tensioned ducts : Modeling by DPSM Technique

This paper presents both theoretical and experimental aspects of a measurement problem in the field of non-destructive evaluation. The purpose of our work is to develop a capacitive probe devoted to post-tensioned cable inspection, mainly for bridge monitoring applications. In this paper will successively be presented the industrial problem, the current probe in use, and an original modeling achieved for sensor design and signal processing. In a first step, we will compare the experimental and theoretical data obtained with different devices under test configurations. Then we will discuss about both capabilities of our direct model, on one hand to provide some help in sensor design improvements and on other hand to be inserted in an inverse problem scheme, to get an estimate of some interesting data of our problem from the measured signals.