[ Papers ]

Journal of the Korean Society of Manufacturing Technology Engineers - Vol. 28, No. 2, pp.113-122

ISSN: 2508-5107 (Online)

Print publication date 15 Apr 2019

Received 26 Dec 2018 Revised 10 Apr 2019 Accepted 12 Apr 2019

DOI: https://doi.org/10.7735/ksmte.2019.28.2.113

테라헤르츠파를 이용한 복합재의 투과특성과 비파괴검사 탐상기법

곽영환^a ; 김선규^b ; 정종안^c ; 조영태^d ; 우용득^e ; 임광희^e^{, *}

Nondestructive Evaluation (NDE) Techniques and Penetration Characterization of Composites Using Terahertz Waves

Young-Hwan Kwak^a ; Sun-Kyu Kim^b ; Jong-An Jung^c ; Young-Tae Cho^d ; Yong-Deuck Woo^e ; Kwang-Hee Im^e^{, *}

aDepartment of Mechanical System Eng., Chosun University Graduate School, 309, Pilmun-daero, Dong-gu, Gwangju 61452, Korea
bDivision of Mech. System Eng., Chonbuk Natl. University, 567, Backjedae-ro Duckjin-gu, Jeonju, Jeonbuk-do, 54896, Korea
cDepartment of Mechanical and Automotive Engineering, Songwon University, 73, Songarm-ro, Nam-gu, Gwangju 33209, Korea
dDepartment of Manufacturing Design Eng., Jeonju University, 303, Chunjam-ro, Wansan-gu, Jeonju, Jeonbuk-do, 55069, Korea
eDepartment of Automotive Eng., Woosuk University, 443, Samrae-ro, Wanju-kun, Jeonbuk-do, 55338, Korea

Correspondence to: ^*Tel.: +82-63-290-1473 Fax: +82-63-290-1681 E-mail address: khim@woosuk.ac.kr (Kwang-Hee Im).

Abstract

Recent technology and instrumentation in terahertz waves have provided a reliable field in the electromagnetic spectrum, which is explored for material evaluation and composite testing. Here, we report an investigation of terahertz waves (T-ray) for the nondestructive evaluation of various materials, such as composite materials and lumbers. The T-ray system uses time domain spectroscopy (TDS) and continuous wave. The various materials and composites investigated include non-conducting materials and composites. Terahertz signals in the TDS mode are similar to that of ultrasound; however, unlike ultrasound, a terahertz pulse can detect a smaller crack hidden behind a larger crack without the shadow effect. These exterminations were demonstrated in thick glass fiber reinforced plastics (GFRP) laminates using saw slots and flat bottom holes. Additionally, two prepared lumbers were investigated using the TDS system through image analysis and refractive index measurement. The effectiveness and limitations of T-ray for the NDE of composites are discussed.

Keywords:

T-ray, FRP, Refractive index, Continuous wave, Shadow effect, Lens

Acknowledgments

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) (No.2018R1D1A1B07049775).

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