An Experimental Study for the Effect of the Density of Polypropylene Foams on the Absorption of Impact Energy

폴리프로필렌 폼 밀도가 충격에너지 흡수에 미치는 영향에 대한 실험적 연구

  • Published : 2008.12.31

Abstract

Polypropylene(PP) foams are widely used as protective materials such as automotive bumper and safety helmet, but whose dynamic behaviour are not well defined. In this paper, the compression tests by Split Hopkinson Pressure Bar were conducted to obtain the stress-strain curve and to investigate the effect of density on the absorption of impact energy in the PP foams. Three kinds of foams were chosen depending upon the density. The result of the experiment has revealed that the stiffness of the low-density PP foam is remarkably increased at high strain rate compared with that of the high-density PP foam. And it is also shown that the absorption of impact energy are greatly influenced by the density of PP foam. These results are expected to be utilized for the development of a protective structure with polymer foams.

Keywords

compression test;impact energy;polypropylene;foam;split hopkinson pressure bar

References

  1. R. M. Davies, "A Critical Study of the Hopkinson Pressure Bar", Phil. Trans. A, Vol. 240, pp. 375-457, 1948 https://doi.org/10.1098/rsta.1948.0001
  2. B. Hopkinson, "A Method of Measuring the Pressure Produced in the Detonation of Explosives or by the Impact of Bullets", Phil. Trans. A, Vol. 213, pp. 437-456, 1914 https://doi.org/10.1098/rsta.1914.0010
  3. H. Kolsky, Stress Waves in Solids, New York, 1963
  4. R. M. Lacey, "Fifth annual symposium on high speed testing introductions", Boston, J. of Applied Polymer Science, pp. 99-105, 1965
  5. R. K. Traegar, J. of Cellular Plastics, Vol. 12, pp. 403-418, 1976
  6. Han Zhao, "Testing of Polymeric Foams at High and Medium Strain Rates", Polymer Testing Vol. 16, pp. 507-516, 1997 https://doi.org/10.1016/S0142-9418(97)00012-3