Zinoviy Nazarchuk – författare

The book presents topical theoretical and experimental studies for developing advanced methods of detecting materials fracture and assessing their structural state using acoustic emission. It introduces new mathematical models characterizing the displacement fields arising from crack-like defects and establishes a new criterion for classifying different types of materials fracture based on specific parameters obtained from wavelet transforms of acoustic emission signals. The book applies this approach to experimental studies in three types of materials—fiber-reinforced composites, dental materials, and hydrogen-embrittled steels.

This book includes the description, modeling and realization of new optical metrology techniques for technical diagnostics of materials. Special attention is paid to multi-step phase shifting interferometry with arbitrary phase shifts between interferograms, phase shifting and correlation digital speckle pattern interferometry, optical-digital speckle correlation, and digital image correlation, as well as dynamic speckle patterns analysis.

Optoacoustic techniques can be treated as a separate branch of optical metrology and can solve many problems of technical diagnostics, including detection and localization of subsurface defects in laminated composite materials. The utility of such techniques can be increased by illumination of the object via acoustic waves at certain frequencies. Hence, an effective theoretical approach to the modeling of an elastic wave field interaction with an interphase defect, and to defect visualization using dynamic speckle patterns, is also includedin this book. The experimental proof of the proposed approaches was achieved using a specially created hybrid optical-digital system for detection of different subsurface defects.

This book is intended for engineers, researchers and students engaged in the field of nondestructive evaluation of materials and technical diagnostics of structural elements, hybrid optical systems, speckle metrology and optoacoustic imaging techniques.

The book presents theoretical and experimental studies to establish the relationship between volume jumps of the 90° domain wall in a ferromagnetic material and the magnitude of the half-space surface displacement caused by it. A method of evaluating the influence of the external magnetic field on the stress intensity factor at the tip of the crack-like defects in ferromagnets is discussed. The influence of hydrogen on the generation of magneto-elastic acoustic emission signals of ferromagnets is described. The features of magneto-elastic acoustic emission due to the presence of plastic deformation, structural changes, and volumetric damage in such structural materials are shown.