On the uniqueness of the inverse solution in crack determination by the electric potential CT method.

Abstract

The present authors have proposed an electric potential CT method for measuring two- and three-dimensional cracks embedded in a body. In this method, the observed data of electric potential distributions on the surfaces of the body are computer-processed using inversion analyses to identify the location, shape and size of cracks. Numerical simulations and experiments conducted for two- and three-dimensional cracks demonstrated the usefulness of the proposed method. In the present study, the uniqueness of the inverse solution in crack identification by thee electric potential CT method is discussed. It is shown that when the plane in which the crack exists is known in advance, cracks in the plane can be uniquely identified, if the electric potential distribution for an appropriate current application is given. When the cracked plane is not known in advance, the electric potential distributions under two current-application conditions are necessary to determine a single two-dimensional crack embedded in a body. Similarly, the electric potential distributions under three current-application conditions are required to determine a single three-dimensional crack.