Computer diagnostics of surface characteristics of extended cylindrical objects by the active location technique

Abstract

| A computer-diagnostics method for examining characteristics of surface layers in conducting extended solids, based on treating data on radio-wave scattering by these solids in the meter and centimeter bands, is reported. The problem is reduced to solving a system of nonlinear algebraic equations. The computational algorithm and results of numerical experiments are described. The method allows using, as input data, not only asymptotic scattering diagrams, but also amplitude values of the re°ected¯eld measured close to the surface under study. The latter improves solution stability in complex noise-signal situations in which random distortions in receive chains occur. INTRODUCTIONComputer diagnostics is widely used in various elds of research and manufacture, including tomography, introscopy, and nondestructive inspection problems. Under computer diagnostics, we mean a set of algorithms and software resources intended for analyzing characteristics of objects under inspection by treating indirect data about the objects on computers [1]. A fundamental difference between computer and traditional diagnostics consists in the possibility of processing much larger bodies of data about objects under study and in using, in processing data and interpreting results, high-performance computers, advanced calculus-mathematics algorithms, and special-purpose soft-and hardware facilities. The work was supported by the Russian Foundation for Basic Research (grants Nos. 03-07-90060, 03-01-00910). Brought to you by | University of Arizona Authenticated Download Date | 6/3/15 1:49 PM 632 M. M. Lavrent'ev, S. Yu. Zharinov, S. M. Zerkal, and M. S. Soppa At present, computer diagnostics remains the main tool for solving the majority of nondestructive inspection problems. Computer diagnostics enables easy automation of diagnosing, data processing and archiving procedures, and makes it possible to improve inspection and solution quality. Nondestructive inspection allows one to test constructions and mechanisms at the design stage and monitor them during exploitation, thus providing the possibility, using resources of elements in largest possible extent, to replace and repair, in proper time, those of them out of imposed requirements.The present-day availability of high-performance computing facilities stimulates the demand for development and industrial application of novel nondestructive inspection methods that optimally use these fresh possibilities. Another reason for the evergrowing demand for nondestructive inspection methods is that they, if used, are capable of substantially reducing risks of man-caused accidents and catastrophes, thus yielding substantial ecomonical and ecological e¬ects.At present, a great number of computer diagnostics algorithms are available. In most cases, mathematical formulation and solution of a computer-diagnostics problem can be reduced to solving operator equations. Solving such equations often presents an ill-posed problem [2{4]. In searching for approximate solutions, regularization procedures are...

Mathematical modelling of the microwave-diagnostics of impedance surfaces for the reflected signal of unknown phase

“…An important problem of science and engineering is to study methods of microwave diagnostics and remote sounding by electromagnetic waves of various frequency and intensity [1,2]. In this direction, modern approaches of computational mathematics have been actively developed and specialized software and hardware have been designed.…”