Reconstruction of Multiple Cracks from Experimental , Electrostatic Boundary Measurements

This paper describes an algorithm for recovering a collection of linear cracks in a homogeneous electrical conductor from boundary measurements of voltages induced by speci ed current uxes. The technique is a variation of Newton's method and is based on taking weighted averages of the boundary data. We also describe an apparatus that was constructed speci cally for generating laboratory data on which to test the algorithm. We apply the algorithm to a number of di erent test cases and discuss the results. This research was carried out while the rst author was in residence at the Institute for Computer Applications in Science and Engineering (ICASE), NASA Langley Research Center, Hampton, VA 23681, which is operated under National Aeronautics and Space Administration contracts NAS1-18605 and NAS119480; the third author is partially supported by National Science Foundation Grant DMS-9202042 and AFOSR Contract 89-NM-605.