Graduate student Eunsong Lee (Master's program in Flexible Printed Electronics, Los Alamos National Laboratory-Jeonbuk National University Engineering Institute-Korea; supervised by Professor Kang Rae-hyung) presented a research technology to prevent loosening of bolt-and-nut fastenings, which are widely used in the automotive and aerospace industries, at the recent Fall Conference of the Korean Society for Nondestructive Testing and received the Outstanding Paper Presentation Award.

Lee presented research results that addressed the difficulty of accurately measuring actual fastening preload of bolt-and-nut joints—used in mechanical, automotive, aerospace, architectural, and civil engineering applications—because these joints expand and contract with changes in ambient temperature.

The technique, which measures based on ultrasonic signals, builds on prior research but was praised for proposing a method that remains applicable even when fastening length varies or when different bolt-and-nut combinations are used.

The study was conducted through collaborative research with Hyundai Motor Company, and it is significant that the team has secured a technique that can proactively prevent bolt-and-nut loosening not only in the domestic automotive industry but also in aviation fields such as UAM (Urban Air Mobility).

In addition, by developing their own equipment, sensors, and software to replace those previously used by companies, the team is expected to contribute to the localization of materials, parts, and equipment.

The research team of Professor Kang Rae-hyung, in which graduate student Eunsong Lee conducts research activities, recently became the first in the world to develop a detection technology for adhesive delamination defects in heat-resistant composite materials—a long-standing challenge in the defense sector—and has completed technology transfer to a domestic company. The team is devoting efforts to developing nondestructive testing technologies applicable to structures composed of diverse materials.

Recently, in particular, the team has been conducting research to improve the reliability of carbon composite structures and automotive structures developed by local companies based on nondestructive testing technologies. Through activities to attract nonlocal companies to the province and collaboration with overseas institutions, the team is demonstrating outstanding research capabilities and contributing to the development of the region's key industries.