Eddy-Current Inversion of Flaw Data From Flat-Bottomed Holes
The demands on our nondestructive evaluation techniques are increasing every year as our technical society becomes more and more complex. Rapid, accurate, and cheap inspection methods are needed to insure the safety, reliability, and economy of large power systems, transportation systems, and many gadgets on which our society has become dependent. Eddy-current tests have the required speed and the potential for the required accuracy and low cost. However, because of their complex nature, it has been costly to design these tests and interpret the data. To design more sensitive tests we need to be able to accurately compute the change in the eddy-current signal caused by a defect (the “forward” problem) in the presence of all of the other properties in the test. Then, to evaluate the data from the test we need to compute the defect size and location from the change in the eddy-current signal (the “inverse” problem) in the presence of the other property variations.