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다양한 비파괴 측정 방법에 의한 CFRP의 BVID 분석

Barely Visible Impact Damage Detection Analyses of CFRP by Various NDE Techniques

  • 임현민 (한국항공대학교 항공우주 및 기계공학과) ;
  • 이보영 (한국항공대학교 항공우주 및 기계공학과) ;
  • 김영국 (인하대학교 공과대학 자율전공학부)
  • 투고 : 2013.05.10
  • 심사 : 2013.06.07
  • 발행 : 2013.06.30

초록

본 연구에서는 탄소섬유강화플라스틱(CFRP, carbon fiber reinforced plastics)에 충격을 가하여 발생하는 결함에 대한 분석을, 특히 눈으로 식별이 어려운 손상(Barely Visible Impact Damage: BVID)을 중심으로 진행하였다. 낙하형 충격시험기를 통하여 충격 시험을 진행하였고, 추의 자유 낙하를 통하여 실제 항공기에 적용된 복합재료에 충격에 의한 손상을 모사한 후, 표면과 내부에 다양한 비파괴 검사를 적용하여 충격에너지에 따른 시편의 결함 거동을 확인하고 살펴보았다. 이를 위해 여러 가지 비파괴 검사법을 사용하여 결함을 비교, 분석, 검토하였다. 그 결과 눈으로 식별이 어려운 손상과 이를 측정하기 위해 사용된 각각의 측정법에 따른 특성이 논의되었다. 일반적으로 육안으로 보이는 표면결함보다 큰 결함이 내부에 발생하였으나, 충격에너지가 작아지면 내부결함이 표면결함 보다 작을 수 있다는 사실이 관찰되었다.

This study aims to detecting and analyzing the defects of damaged carbon fiber reinforced composites after impacts, particularly focusing on barely visible impact damages. The impact test was progressed by a drop-weight machine and applied to introduce simulated damages on laminated composites used in aircrafts. Various nondestructive testing (NDT) techniques were applied to identify the defects on the specimens with different levels of impact energies. Based on the measurements data, the levels of the barely visible impacts, and the applicability and effectiveness of the detection methods were discussed. Generally, the results demonstrated that their inner damages contained bigger footprints than those on the surfaces. However, when the damage energy was low, it was found that the inner damage size could be smaller than those appeared on the surfaces.

키워드

참고문헌

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피인용 문헌

  1. Improvement in Accuracy of a Multi-Joint Robotic Ultrasonic Inspection System for the Integrity of Composite Structures vol.10, pp.19, 2013, https://doi.org/10.3390/app10196967