DOI QR코드

DOI QR Code

Effect of Different Energy Frames on the Impact Velocity of Strain Energy Frame Impact Machine

에너지 프레임 종류에 따른 변형에너지 프레임 충격시험장치의 충격속도

  • PARK, Seung Hun (Department of Civil and Environmental Engineering, Sejong University) ;
  • PARK, Jun Kil (Department of Civil and Environmental Engineering, Sejong University) ;
  • TRAN, Tuan Kiet (Department of Civil and Environmental Engineering, Sejong University) ;
  • KIM, Dong Joo (Department of Civil and Environmental Engineering, Sejong University)
  • Received : 2014.11.11
  • Accepted : 2015.03.16
  • Published : 2015.08.30

Abstract

This research investigated the effects of diameter and material of energy frame on the impact velocity or strain rate of Strain Energy Frame Impact Machine (SEFIM). The impact speed of SEFIM have been clearly affected by changing the diameter and material of the energy frame. The reduced diameter of the energy frame clearly increased the impact velocity owing to the higher strain at the moment of coupler breakage. And, titanium alloy energy frame produced the fastest speed of impact among three materials including steel, aluminum and titanium alloys because titanium alloy has faster wave velocity than steel. But, aluminium energy frame was broken during impact tests. In addition, the tensile stress versus strain response of high performance fiber reinforced cementitious composites at higher and wider strain rates between 10 and 72 /sec was successfully obtained by using four different energy frames.

본 연구에서는 탄성변형 에너지를 이용하는 충격실험장치인 변형에너지 충격시험장치(SEFIM)의 변형률 속도를 증가시키기 위하여, 탄성변형 에너지가 저장되는 에너지 프레임의 직경 및 재질을 다르게 하여 그 영향을 조사하였다. 현재 강재를 에너지 프레임의 재질로 사용한 SEFIM의 발현 가능한 변형률 속도범위는 10-40 /sec까지이지만, 에너지 프레임의 재질과 직경을 다르게 하여 충격 시 변형률 속도가 72 /sec까지 증가되었다. 충격실험에 사용된 HPFRCCs는 장섬유 1%와 단섬유 1%를 함께 초고강도 콘크리트에 혼입하였다. 정적 변형률 속도에서 뿐만 아니라, 네 가지 종류의 에너지 프레임을 사용한 높은 변형률 속도(14-72 /sec)에서도 변형경화 거동을 나타내었다. 에너지 프레임의 직경을 기존의 35 mm에서 25 mm로 작게 변경함에 따라서 변형률 속도가 증가하였으며, 에너지 프레임 재질을 강재, 알루미늄 그리고 티타늄으로 변경함에 따라, 강재보다 높은 탄성파 속도를 가지고 많은 크기의 탄성변형 에너지를 저장할 수 있는 티타늄 합금을 사용한 경우 더욱 높은 변형률 속도(72 /sec)를 생성하였다. 알루미늄 재질의 에너지 프레임의 경우 충격실험 시 작용되었던 응력으로 인해 탄성영역을 벗어나 소성변형을 일으켜 파단되어 본래 가지고 있던 성질을 발현하지 못하였다.

Keywords

References

  1. Li, V. C., Wang, S., and Wu, C., "Tensile strain-hardening behavior of polyvinyl alcohol engineered cementitious composite (PVA-ECC)", ACI Materials Journal, Vol.98, 2001, pp.483-492.
  2. Yang, E. and Li, V.C., "Rate dependence in engineered cementitious composites", Proceedings, HPFRCC-2005 international workshop. Honolulu, Hawaii, USA, 2005.
  3. Parant, E. P., et al., "Strain rate effect on bending behavior of new ultra-high-performance cement based composite", ACI Materials Journal, Vol.104, No.5, September, 2007.
  4. Kim, D. J., Tawil, S. E., and Naaman, A. E., "Rate-dependent tensile behavior of high performance fiber reinforced cementitious composites", Materials and Structures, Vol.42, 2009, pp.399-414. https://doi.org/10.1617/s11527-008-9390-x
  5. Wille, K., Tawil, S. E., and Naaman, A. E., "Strain Rate Dependent Tensile Behavior of Ultra-High Performance Fiber Reinforced Concrete", High Performance Fiber Reinforced Cement Composites 6. Springer Netherlands, 2012, pp.381-387.
  6. Douglas, K. S. and Billington, S. L., "Rate dependence in high-performance fiber reinforced cementbased composites for seismic applications", Proceedings, HPFRCC-2005 international workshop, Honolulu, Hawaii, USA, 2005.
  7. Kim, Y. W., et al., "Flexural and Impact Resisting Performance of HPFRCCs Using Hybrid PVA Fibers", Journal of the Korea Concrete Institute, Vol.24, No.3, 2009, pp.705-712.
  8. Mechtcherine, V., et al., "Behaviour of strain-hardening cement-based composites under high strain rates", Journal of Advanced Concrete Technology, Vol.9, No.1, 2011, pp.51-62. https://doi.org/10.3151/jact.9.51
  9. Yoo, D. Y., et al., "Evaluating Impact Resistance of Externally Strengthened Steel Fiber Reinforced Concrete Slab with Fiber Reinforced Polymers", Journal of the Korea Concrete Institute, Vol.24, No.3, 2012, pp.293-303. https://doi.org/10.4334/JKCI.2012.24.3.293
  10. Yoo, D. Y., et al., "Enhancement of Impact Resistance of Layered Steel Fiber Reinforced High Strength Concrete Beam", Journal of the Korea Concrete Institute, Vol.24, No.4, 2012, pp.369-379. https://doi.org/10.4334/JKCI.2012.24.4.369
  11. Nam, J. S., et al., "Evaluation on the Impact Resistant Performance of Fiber Reinforced Concrete by High-Velocity Projectile and Contacted Explosion", Journal of the Korea Concrete Institute, Vol.25, No.1, 2013, pp.107-114. https://doi.org/10.4334/JKCI.2013.25.1.107
  12. Tran, K. T. and Kim, D. J., "Investigating direct tensile behavior of high performance fiber reinforced cementitiois composites at high strain rates", Cement and Concrete Research, Vol.50, 2013, pp.62-73. https://doi.org/10.1016/j.cemconres.2013.03.018
  13. Tran, K. T. and Kim, D. J., "High strain rate effects on direct tensile behavior of high performance fiber reinforced cementitious composites", Cement and Concrete Composites, Vol. 45, 2014, pp.186-200. https://doi.org/10.1016/j.cemconcomp.2013.10.005
  14. Bindiganavile, V., Banthia, N., and Aarup, B., "Impact response of ultra-high-strength fiber-reinforced cement composite", ACI Materials Journal, Vol.99, No.6, November-December, 2002.
  15. Naaman, A. E. and Gopalaratnam, V. S., "Impact properties of steel fibre reinforced concrete in bending", International Journal of Cement Composites and Lightweight Concrete, Vol.5, No.4, 1983, pp.225-233. https://doi.org/10.1016/0262-5075(83)90064-7
  16. Habel, K. and Gauvreau, P., "Response of ultra-high performance fiber reinforced concrete (UHPFRC) to impact and static loading", Cement and Concrete Composites, Vol.30, 2008, pp.938-946. https://doi.org/10.1016/j.cemconcomp.2008.09.001
  17. Duell, J. M., "Impact Testing of Advanced Composites", Advanced Topics in Characterization of Composites, 97, 2004.
  18. Yu, R., Spiesz, P., and Brouwers, H. J. H., "Impact resistance capacity of a green Ultra-High Performance Hybrid Fibre Reinforced Concrete (UHPHFRC): Experimental and modeling study", International Conference on Non-Traditional Cement and Concrete, June 16-19, 2014.
  19. Millon, O., et al., "Fiber-reinforced ultra-high performance concrete under tensile loads", DYMAT-International Conference on the Mechanical and Physical Behaviour of Materials under Dynamic Loading, Vol. 1, EDP Sciences, 2009.
  20. Cadoni, E., Meda, A., and Plizzari, G. A., "Tensile behaviour of FRC under high strain-rate", Materials and Structures, Vol.42, 2009, pp.1283-1294. https://doi.org/10.1617/s11527-009-9527-6
  21. Tran, T. K. and Kim, D. J., "Strain energy frame impact machine (SEFIM)", Journal of Advanced Concrete Technology, Vol. 10, 2012, pp.126-136. https://doi.org/10.3151/jact.10.126
  22. Park, J. J., et al., "Influence of the ingredients on the compressive strength of UHPC as a fundamental study to optimize the mixing proportion", Proceeding of Second International Symposium on Ultra High Performance Concrete, Germany, E. Fehling, M. Schmidt and S. Sturwald, Co-Editor, Kassel University, Germany, 2008, pp.105-112.