Field Indentation Microprobe for Structural Integrity Evaluation

U.S. Patent No. 4,852,397, issued August 1, 1989, is the foundational intellectual property document for ABI® technology. It claims the complete Field Indentation Microprobe system including: the ABI® testing method, the apparatus for deriving yield strength, flow curve, and fracture toughness from indentation load-displacement data, the NDE integration architecture combining indentation with ultrasonic and video inspection, and the Lüders strain measurement approach.

The patent established the commercial basis for Advanced Technology Corporation (ATC) and subsequently ABI® Services LLC. While the patent has since expired, it remains an important technical reference because the patent claims define — in legally precise language — the essential elements of the ABI® method that distinguish it from other indentation techniques.

The patent's detailed description of the ABI® apparatus and method also served as the technical blueprint from which independent researchers (notably IGCAR in India) built their own ABI® systems for research purposes, contributing to the broad independent validation of the technology.