Composites Research

The Korean Society for Composite Materials (한국복합재료학회)
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A Study on the Atmospheric Pressure Control of the VARTM Process for Increasing the Fiber Volume Fraction and Reducing Void

섬유부피분율 증가와 공극 감소를 위한 VARTM 공정의 대기압 제어에 관한 연구

  • Kwak, Seong-Hun (Technology & Innovation Division, Gyeongbuk Hybrid Technology Institute) ;
  • Kim, Tae-Jun (Technology & Innovation Division, Gyeongbuk Hybrid Technology Institute) ;
  • Tak, Yun-Hak (Technology & Innovation Division, Gyeongbuk Hybrid Technology Institute) ;
  • Kwon, Sung-Il (Defense Engineering Team, Hankuk Fiber Co., Ltd.) ;
  • Lee, Jea-Hyun (Defense Engineering Team, Hankuk Fiber Co., Ltd.) ;
  • Kim, Sang-Yong (Aerospace Technology Research Institute, Agency for Defense Development) ;
  • Lee, Jong-Cheon (Aerospace Technology Research Institute, Agency for Defense Development)
  • Received : 2020.12.03
  • Accepted : 2021.03.03
  • Published : 2021.04.30
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Abstract

VARTM (Vacuum-assisted resin transfer molding) process is a low-cost process technology and affiliated with OoA (Out of Autoclave). Besides, it has been widely used in various fields. However, because of its lower quality than the autoclave process, it isn't easy to apply the VARTM process to the aerospace industry, which requires high reliability. The main problem of the VARTM process is the loss of mechanical properties due to the low fiber volume fraction and high void content in comparison to the autoclave. Therefore, many researchers have studied to reduce void and increase fiber volume fraction. This study examines whether the method of controlling atmospheric pressure could increase the fiber volume fraction and reduce void during the resin impregnation process. Reliability evaluation was confirmed by compressive strength test, fiber volume fraction analysis, and optical microscopy. As a result, it was confirmed that increasing the atmospheric pressure step by step in the VARTM process of impregnating the preform with resin effectively increases the fiber volume fraction and reduces void.

VARTM(Vacuum-assisted resin transfer molding) 공정은 OoA(Out of Autoclave)에 속하는 저가형 공정기술로 다양한 분야에 널리 사용되어 왔다. 그러나 오토클레이브 공정보다 품질이 낮아 고신뢰성이 요구되는 항공산업에는 적용하기 어려웠다. VARTM 공정의 주요 문제는 오토클레이브 대비 낮은 섬유부피분율과 높은 Void 함량에 의한 기계적 물성의 손실이었다. 따라서 많은 연구자들이 Void를 줄이고 섬유부피분율을 높일 수 있는 연구를 수행해 왔다. 이러한 연구의 흐름에 따라 본 연구에서는 수지 주입 과정 중 대기압을 제어하는 방법이 섬유부피분율을 높이고 Void를 감소시킬 수 있는지 검토하였다. 신뢰성 평가는 Void와 연관성이 있는 압축강도시험, 섬유부피분율 분석, 광학현미경 촬영을 통해 확인하였다. 결과적으로 VARTM 공정에서 수지 주입과정 중 대기압을 단계별로 높이는 방법이 섬유부피분율 증가와 Void 감소에 직접적인 효과가 있음을 확인하였다.

Keywords

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