Original Article
  • A Study on Damage Detection of Fasteners Using Self-sensing of CFRP

  • Min Jong Lee*, Donghyeon Lee**, Yongseok Lee*, Ki-Eek Kwon****, Zuo-Jia Wang****, Woo-Seok Shim****, Mantae Kim***†, Dong-Jun Kwon *,**†

  • * School of Materials Science & Engineering Major in Polymer Engineering, Gyeongsang National University, Jinju, Korea
    ** Department of Materials Engineering and Convergence Technology, Research Institute for Green Energy Convergence Technology Gyeongsang National University, Jinju, Korea
    *** Aerospace Convergence Materials Center, Korea Institute of Ceramic Engineering and Technology, Jinju, Korea
    **** R&D Center, Dong Yang Piston Co., Ltd, Ansan 15420, Korea

  • CFRP의 자가 센싱을 이용한 패스너 손상 감지 연구

  • 이민종*·이동현**·이용석*·권기익****·왕작가****·심우석****·김만태***† ·권동준*,**†

  • This article is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The use of composite materials for structural fasteners is increasingly common, making it crucial to assess the deformation of these fasteners under fatigue behavior. In this study, clamp-type fasteners were manufactured using carbon fiber reinforced composites, and their structural stability and sectional damage rates were evaluated using electrical resistance measurement during fatigue behavior. While clamp-type composite fasteners exhibited minimal deformation in flat sections, significant deformation occurred in the bent sections due to fatigue. It was observed that insufficient angular stability led to concentrated damage in the bent sections. The dynamic fatigue behavior showed that the length change rate of the composite fasteners was within 0.6%, but the angular change rate reached up to 6%, indicating that the bent sections are the most critical areas. By utilizing the self-sensing capability of the composite fasteners, sectional damage behavior was assessed through electrical resistance measurement. Significant damage was noted in the bent sections due to fatigue, and 3D-CT results revealed substantial deformation and interfacial damage when the initial bend angle of the fasteners was less than 90 degrees. These findings highlight the importance of reinforcing the stiffness of the bent sections and establishing systematic angular standards in the development of composite fasteners.


복합재료를 사용하여 구조물의 패스너로 활용하는 사례가 증가하고 있으며, 이러한 패스너의 피로 거동에 따른 변형을 확인하는 것이 중요하다. 본 연구에서는 복합재료 패스너로서 탄소섬유 강화 복합재료를 사용하여 클램프 형태의 패스너를 제조하고, 피로 거동 시 구조적 안정성과 전기저항 측정법을 이용한 구간별 손상률 평가를 실시하였다. 클램프형 복합재료 패스너는 평면 구간에서는 변형이 적었으나, 굴곡부에서는 피로 거동에 따라 변형이 크게 발생하였다. 각도 안정성이 부족한 경우 클램프의 손상이 굴곡부에 집중됨을 확인하였다. 동적 피로 거동에 따라 복합재료 패스너의 길이 변화율은 0.6% 이내였으나, 각도 변화율은 최대 6%까지 발생하여 굴곡부가 가장 중요하였다. 복합재료 패스너의 자체 감지 능력을 이용하여 전기저항 측정법을 통해 구간별 손상 거동을 평가하였다. 피로 거동에 따라 굴곡부의 손상이 두드러졌으며, 초기 패스너의 굴곡부가 90도 이하일 경우 큰 변형과 계면 손상이 발생함을 3D-CT 결과로 관측할 수 있었다. 이러한 결과를 바탕으로, 복합재료 패스너를 개발할 때 굴곡부의 강성 보완과 체계적인 각도 기준 제시가 중요함을 확인하였다.


Keywords: 탄소섬유 복합재료(Carbon fiber Reinforced Plastic), 자체 감지능(Self-Sensing), 패스너(Fastener), 굴곡 (Bends), 전기저항 측정법(Electrical resistance measurement)

This Article

Correspondence to

  • Mantae Kim***, Dong-Jun Kwon *,**

  • * School of Materials Science & Engineering Major in Polymer Engineering, Gyeongsang National University, Jinju, Korea
    ** Department of Materials Engineering and Convergence Technology, Research Institute for Green Energy Convergence Technology Gyeongsang National University, Jinju, Korea
    *** Aerospace Convergence Materials Center, Korea Institute of Ceramic Engineering and Technology, Jinju, Korea

  • E-mail: ginggiscan@kicet.re.kr, djkwon@gnu.ac.kr