Nano Engineering & Technology

Biography

Jung-Ryul Lee is an Associate Professor in the Department of Aerospace Engineering at Korea Advanced Institute of Science and Technology, South Korea. His research interest includes smart hangar (Inventor), wireless sensing (wireless strain and ultrasonic sensing devices), pyro shock measurement and propagation imaging (Inventor), laser ultrasonic propagation imaging (Inventor), scanning microwave imaging for stealth and radome structures (Inventor), machine-learning based structural diagnosis and integrated system health monitoring. His application field encompasses space launchers, unmanned air vehicles, wind turbine, power plants, railway structures, automobile, public safety and radome/stealth structures. He has published over 300 articles and patents in this area and received several awards including Young Scientist Award by Sustainable Aviation Research Society in 2016, Grand Prize of the Best Papers by Ministry of Land in 2013, Infrastructure and Transport in Korea, Global Research & Development Center Award by Ministry of Education and Science and Technology in 2011.

Abstract

Many studies for composite radar absorbing structures (RAS) and delamination have been performed. The purpose of this study is to understand a correlation between lightning damage and stealth performance of the RAS due to lightning strikes. The RAS in this study has two different layers with two different materials. The material for one layer is glass/epoxy (GFRP) and the other material for the other layer is glass/epoxy-MWCNT. To make the damage on the RAS composite specimens, artificial lightning strike test was performed according to NASA reference. To examine the correlation between the lightning damage and the stealth performance, a non-destructive inspection (NDI) and reflection loss measurement were conducted using pulse-echo ultrasonic propagation imager (PE-UPI) system and dual port scanning free space measurement (SFSM) system respectively. The lightning damage is visualized in C-scan results using PE-UPI and the stealth performance is compared in the X-band (8.2/12.4 GHz). It was verified that the lightning damage affected the radar absorbing performance of the RAS. The performance change of the reflection loss was related to the location and size of the damage.