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Restoration Of Defaced Serial Numbers Using Lock-In Infrared Thermography (Part I), Ikwulono Unobe, Lisa Lau, John Kalivas, Rene Rodriguez, Andrew D. Sorensen
Restoration Of Defaced Serial Numbers Using Lock-In Infrared Thermography (Part I), Ikwulono Unobe, Lisa Lau, John Kalivas, Rene Rodriguez, Andrew D. Sorensen
Civil and Environmental Engineering Faculty Publications
Infrared thermal imaging is an evolving approach useful in non-destructive evaluation of materials for industrial and research purposes. This study investigates the use of this method in combination with multivariate data analysis as an alternative to chemical etching; a destructive method currently used to recover defaced serial numbers stamped in metal. This process involves several unique aspects, each of which works to overcome some pertinent challenges associated with the recovery of defaced serial numbers. Infrared thermal imaging of metal surfaces provides thermal images sensitive to local differences in thermal conductivity of regions of plastic strain existing below a stamped number. …
Restoration Of Defaced Serial Numbers Using Lock-In Infrared Thermography (Part Ii), Ikwulono Unobe, Lisa Lau, John Kalivas, Rene Rodriguez, Andrew D. Sorensen
Restoration Of Defaced Serial Numbers Using Lock-In Infrared Thermography (Part Ii), Ikwulono Unobe, Lisa Lau, John Kalivas, Rene Rodriguez, Andrew D. Sorensen
Civil and Environmental Engineering Faculty Publications
This paper details continuing work on the development of a substantive non-destructive method to recover defaced serial numbers stamped or laser engraved into metallic objects based on lock-in infrared thermography. This method relies on the existence of a local zone of plastic strain created from stamping pressures in mechanically stamped pieces and a heat-affected zone in laser engraved samples, both extending to depths below the visible characters. The grain structure within these zones is dislocated due to the external forces applied. These deformed areas are exposed to the surface when the serial numbers are defaced. Infrared thermography utilises the change …