DOI QR코드

DOI QR Code

A study on the way to improve strength of LTV's FRP structures by optimizing laminated structure

전술차량 FRP 구조물 적층 구조 최적화를 통한 강도개선 방안 연구

  • Kim, Seon-Jin (Land System Team 5, Defence agency of Technology and Quality(DTaQ)) ;
  • Park, Jin-Won (Planning & Coordination Team, DTaQ) ;
  • Kim, Sung-Gon (Land System Team 5, Defence agency of Technology and Quality(DTaQ)) ;
  • Kang, Tae-Woo (Land System Team 5, Defence agency of Technology and Quality(DTaQ)) ;
  • Shin, Cheol-Ho (Land System Team 5, Defence agency of Technology and Quality(DTaQ))
  • 김선진 (국방기술품질원 기동화력5팀) ;
  • 박진원 (국방기술품질원 기획조정팀) ;
  • 김성곤 (국방기술품질원 기동화력5팀) ;
  • 강태우 (국방기술품질원 기동화력5팀) ;
  • 신철호 (국방기술품질원 기동화력5팀)
  • Received : 2019.02.15
  • Accepted : 2019.05.03
  • Published : 2019.05.31

Abstract

This paper presents the means of improving the strength of LTV's FRP structure for resolve and prevent quality problems. LTV secures enough kerb weight by applying FRP materials at hood and rear van assembly. However, because of FRP's inherent limitations, many initial quality problems such as crack at connections have occurred. Moreover, hood assy' is concerned about fall of endurance, because hood assy' have operated in abnormal condition. Therefore, this study executes lamination structure optimizations of FRP structure for improving bending strength. As a results, hood and rear van's bending strength at connections is improved 8.1 times and 1.5 times, respectively. Also hood assy's plate secures endurance life and improve 1.7 times of critical load about abnormal operating conditions through 1.4 times improvement of bending strength.

본 연구는 전술차량에 적용된 FRP 구조물의 품질문제 해소 및 예방을 위한 강도개선 방안에 대한 것이다. 소형전술차량은 후드조립체와 후방밴 조립체 등에 FRP 소재를 적용하여 전체적인 차량의 여유중량(공차중량)을 확보하였다. 그러나 FRP가 갖는 태생적인 한계로 인해 접합부 균열과 같은 초기 품질문제가 다수 발생되었다. 더구나, 후드조립체는 개발 시 고려한 조건과 다른 비정상적인 조건으로 운용됨을 확인하였다. 이러한 비정상적인 조건으로 장기간 장비 운용 시 해당 부품의 내구수명 저하가 우려되었다. 따라서, 본 연구에서는 이러한 FRP 구조물의 문제점에 대한 개선과 운용개념 변화에 따른 설계 안전율 추가 확보를 위한 굴곡강도 향상을 목표로 적층구조 최적화를 수행하였다. 그 결과, 접합부는 FRP 소재 적층수를 증가시킴으로써 후드조립체와 후방밴 조립체의 굴곡강도가 각각 8.1배, 1.5배 개선되었다. 또한, 후드조립체의 모재 부위는 FRP 적층구조 최적화를 통해 굴곡강도 1.4배 향상시켰으며, 그 결과 비정상 운용조건에 대한 내구수명 확보 및 한계하중 1.7배 개선효과를 확인하였다.

Keywords

SHGSCZ_2019_v20n5_468_f0001.png 이미지

Fig. 1. Composite material parts at LTV

SHGSCZ_2019_v20n5_468_f0002.png 이미지

Fig. 2. The method of resin transfer manufacturing[6]

SHGSCZ_2019_v20n5_468_f0003.png 이미지

Fig. 3. The quality problem of FRP structure

SHGSCZ_2019_v20n5_468_f0004.png 이미지

Fig. 4. The production method of hood and rear van assy'

SHGSCZ_2019_v20n5_468_f0005.png 이미지

Fig. 5. The change of operational concept

SHGSCZ_2019_v20n5_468_f0006.png 이미지

Fig. 6. The shapes of chop mat(left) and combo mat(right)

SHGSCZ_2019_v20n5_468_f0007.png 이미지

Fig. 7. The examples of identified defect on samples

SHGSCZ_2019_v20n5_468_f0008.png 이미지

Fig. 8. The verificaton test method

Table 1. The problems of FRP structures and their laminated structure, bending strength

SHGSCZ_2019_v20n5_468_t0001.png 이미지

Table 2. The problems of FRP structures and their laminated structure, bending strength

SHGSCZ_2019_v20n5_468_t0002.png 이미지

Table 3. The results of FRP lamination of hood’s plate

SHGSCZ_2019_v20n5_468_t0003.png 이미지

Table 4. The results of limit load test

SHGSCZ_2019_v20n5_468_t0004.png 이미지

Table 5. The optimization results of lamination structure for LTV's FRP parts

SHGSCZ_2019_v20n5_468_t0005.png 이미지

References

  1. The criteria of Required Operational Capability (Appendix), Republic of Korea Army Headquaters, 2014
  2. J. W. Park, D. H. Kim, B. G. Song, S. J. Kim, S. J. Yoon, "A study on the way to improve the rear van's durability of korean light tactical vehicle", Journal of the korean society for quality management, Vol. 46, No. 2, pp. 269-282, 2018 DOI: https://dx.doi.org/10.7469/JKSQM.2018.46.2.269
  3. Y. M. Ryu, E. P. Yoon, Y. S. Yoon, S. H. Lee, "Stiffness Comparison with Design of GFRP Roof Panels Prepared by RTM Method", The Korean Society of Automotive Engineers, No. 98370073, pp. 32-38, 1998
  4. J. H. Mun, K. D. Han, S. H. Hong, Y. G. Kwon, R. M. Do, "A study on development of automobile parts using CFRP", The Korean Society of Manufacturing Process Engineers, Jeju, Korea, pp. 59, November, 2011
  5. C. Kim, S. Y. Lee, "Optimum design and analysis of a fiber-reinforced polymer composite side door used for a mid-size passenger car", The Korean Society of Automotive Engineers, Gyoungju, Korea, pp. 770, May, 2015
  6. M. K. Um, J. W. Lee, Auto journal, pp. 32-35, KSAE, 2017
  7. H. K. Choi, K. W. Nam, S. H. Ahn, "Strength characteristics of FRP copositie materials for ship structure", The Korean society of ocean engineers, Vol. 27, No. 4, pp. 45-54, 2013
  8. H. C. Song, J. S. Yum, "A study onf the mechanical properties of fiberglass reinforcements with constitution of lay-up, manufacturing method and resins", The Korean society of ocean engineers, Vol. 24, No. 5, pp. 75-80, 2010
  9. F. Mohammed, O. Shinji, V. Vladimir, "The effect of matrix cracking on mechanical properties in FRP laminates", Mechanics of advanced materials and modern processes, 2018 DOI : https://doi.org/10.1186/s40759-018-0036-6
  10. J. W. Jeong, Experimental study of fiber reinforced polymer composite decks and beams, Master's thesis, Sejong university, Seoul, Korea, p. 41-45, 2004