A novel approach to crack refinement measurement under impact loading based on OFDR technique

Abstract The dynamic crack propagation characteristics of brittle materials are a crucial focus in impact dynamics. The randomness of crack growth under impact loading poses significant challenges to accurately monitoring crack behavior during experiments. In this study, two novel crack refinement measurement techniques based on optical frequency domain reflectometry technology were developed to provide more comprehensive strain distribution data under impact loading and to capture detailed crack propagation behavior. Additionally, a trending algorithm was introduced to process large datasets and accurately pinpoint crack locations. The study begins by presenting the two innovative deployment methods and the fabrication process of custom specimens. After conducting impact tests on the specimens, the resulting strain distribution data were compared with actual crack propagation. The results demonstrated precise crack location identification down to the millimeter level, and the crack extension path was accurately mapped using strain profiles from fiber-optic measurements. These findings validate the effectiveness of the proposed approach, which shows great potential for accurately monitoring, locating, and quantifying cracks using distributed optical fibers.