DOI QR코드

DOI QR Code

Study of dynamic mechanical behavior of aluminum 7075-T6 with respect to diameters and L/D ratios using Split Hopkinson Pressure Bar (SHPB)

  • Kim, Eunhye (Department of Mining Engineering, Colorado School of Mines) ;
  • Changani, Hossein (Department of Mining Engineering, University of Utah)
  • 투고 : 2014.11.29
  • 심사 : 2015.08.04
  • 발행 : 2015.08.25

초록

The aluminum 7075-T6 is known as an alloy widely used in aircraft structural applications, which does not exhibit strain rate sensitivity during dynamic compressive tests. Despite mechanical importance of the material, there is not enough attention to determine appropriate sample dimensions such as a sample diameter relative to the device bar diameter and sample length to diameter (L/D) ratio for dynamic tests and how these two parameters can change mechanical behaviors of the sample under dynamic loading condition. In this study, various samples which have different diameters of 31.8, 25.4, 15.9, and 9.5 mm and sample L/D ratios of 2.0, 1.5, 1.0, 0.5, and 0.25 were tested using Split Hopkinson Pressure Bar (SHPB), as this testing device is proper to characterize mechanical behaviors of solid materials at high strain rates. The mechanical behavior of this alloy was examined under ${\sim}200-5,500s^{-1}$ dynamic strain rate. Aluminum samples of 2.0, 1.5 and 1.0 of L/D ratios were well fitted into the stress-strain curve, Madison and Green's diagram, regardless of the sample diameters. Also, the 0.5 and 0.25 L/D ratio samples having the diameter of 31.8 and 25.4 mm followed the stress-strain curve. As results, larger samples (31.8 and 25.4 mm) in diameters followed the stress-strain curve regardless of the L/D ratios, whereas the 0.5 and 0.25 L/D ratios of small diameter sample (15.9 and 9.5 mm) did not follow the stress-strain diagram but significantly deviate from the diagram. Our results indicate that the L/D ratio is important determinant in stress-strain responses under the SHPB test when the sample diameter is small relative to the test bar diameter (31.8 mm), but when sample diameter is close to the bar diameter, L/D ratio does not significantly affect the stress-strain responses. This suggests that the areal mismatch (non-contact area of the testing bar) between the sample and the bar can misrepresent mechanical behaviors of the aluminum 7075-T6 at the dynamic loading condition.

키워드

참고문헌

  1. Anderson, C., Jr., O'Donoghue, P., Lankford, J. and Walker, J. (1992), "Numerical simulations of SHPB experiments for the dynamic compressive strength and failure of ceramics", Int. J. Fract., 55(3), 193-208. https://doi.org/10.1007/BF00032510
  2. ASTM (2013), E9-09, ASTM international standards
  3. Changani, H., Young, A. and Kim, E. (2013), "Effect of L/D ratio on dynamic response of Aluminum 7076 and the Natural Motoqua Quartzite Sandstone in Saint George, UT using Split Hopkinson Pressure Bar (SHPB) ", 47th US Rock Mechanics/Geomechanics Symposium, San Francisco, CA, USA.
  4. Chiem, C.Y. (1988). "Dynamic effects of microstructures in correlation with macroscopic plasticity of materials at high rates of strain", Impact loading and dynamic behavior of material, Oberursel.
  5. Dai, F., Huang, S., Xia, K. and Tan, Z. (2010), "Some fundamental issues in dynamic compression and tension tests of rocks using split hopkinson pressure bar", Rock Mech. Rock Eng., 43(6), 657-666. https://doi.org/10.1007/s00603-010-0091-8
  6. Davies, E.D.H. and Hunter, S.C. (1963), "The dynamic compression testing of solids by the method of the split hopkinson pressure bar", J. Mech. Phys. Solid., 11(3), 155-179. https://doi.org/10.1016/0022-5096(63)90050-4
  7. Follansbee, P.S. and Kocks, U.F. (1988), "A constitutive description of the deformation of copper based on the use of the mechanical threshold stress as an internal state variable", Acta Metallurgica, 36(1), 81-93. https://doi.org/10.1016/0001-6160(88)90030-2
  8. Gorham, D.A. (1991), "The effect of specimen dimensions on high strain rate compression measurements of copper", J. Phys. D: Appl. Phys., 24, 1489-1492. https://doi.org/10.1088/0022-3727/24/8/041
  9. Gorham, D.A., Pope, P.H. and Cox, O. (1984), "Source of error in very high strain rate compression tests: mechanical properties at high rates of strain", 3rd Conference on the Mechanical Properties of Materials at High Rates of Strain.
  10. Gray, G.T.I. (2000), Classical Split Hopkinson Pressure Bar Testing, ASM Handbook.
  11. Hao, Y. and Hao, H. (2013), "Numerical investigation of the dynamic compressive behaviour of rock materials at high strain rate", Rock Mech. Rock Eng., 46(2), 373-388. https://doi.org/10.1007/s00603-012-0268-4
  12. Hao, Y., Hao, H. and Li, Z.X. (2013), "Influence of end friction confinement on impact tests of concrete material at high strain rate", Int. J. Impact Eng., 60, 82-106. https://doi.org/10.1016/j.ijimpeng.2013.04.008
  13. Haque, M.M., Pickering, F.B. and Hashmi, M.S.J. (1988), "Investigation on microstructural change in copper deformed at strain rates of upto 104 per second", J. Physique, 49(C3), 105-108.
  14. Hauser, F.E., Simmons, J.A. and Dorn, J.E. (1960), "Strain rate effects in plastic wave propagation", Proceeding of Metallurgical Society Conferences.
  15. Kim, D.S. (1993), "The effect of shock-induced damage on comminution of rock materials", University of Utah, Salt Lake City.
  16. Kim, E. and de Oliveira, D.B.M. (2015), "The effects of water saturation on dynamic mechanical properties in red and buff sandstones having different porosities studied with Split Hopkinson Pressure Bar (SHPB)", Appl. Mech. Mater., 752-753, 784-789. https://doi.org/10.4028/www.scientific.net/AMM.752-753.784
  17. Kim, E. and de Oliveira, D.B.M. (2015), "The water saturation effects on dynamic tensile strength in red and buff sandstones studied with Split Hopkinson Pressure Bar (SHPB)", International Conference on Advanced Materials, Structures and Mechanical Engineering, Songdo, South Korea. (in Press)
  18. Klepaczko, J.R. (1988), "An advanced constitutive modelling of rate sensitivity, temperature and strain hardeninq in FCC metals", Impact Loading and Dynamic Behavior of Material, Oberursel.
  19. Kolsky, H. (1949), "An investigation of mechanical properties of materials at very high rate of loading", Proc. Phys. Soc., Section B, 62, 676-700. https://doi.org/10.1088/0370-1301/62/11/302
  20. Maiden, C.J. and Green, S.J. (1966), "Compressive strain rate tests on six selected materials at strain rates from 10-3 to 104 in/in/sec", J. Appl. Mech., 33(3), 496-504. https://doi.org/10.1115/1.3625114
  21. Meyers, M.A. (1994), Dynamic Behavior of Materials, Wiley-Interscience
  22. Sunny, G., Lewandowski, J. and Prakash, V. (2007), "Effects of annealing and specimen geometry on dynamic compression of a Zr-based bulk metallic glass", J. Mater. Res., 22(2), 389-401. https://doi.org/10.1557/jmr.2007.0042
  23. Wang, S.S., Zhang, M.H. and Quek, S.T. (2011), "Effect of specimen size on static strength and dynamic increase factor of high-strength concrete from SHPB test", J. Test. Eval., 39(5), 898-907.
  24. Woldesenbet, E. and Vinson, J.R. (1999), "Specimen geometry effects on high-strain-rate testing of graphite/epoxy composites", Aiaa J., 37(9), 1102-1106. https://doi.org/10.2514/2.820
  25. Xiao, J. and Shu, D.W. (2013), The Effect of Specimen Size on the Dynamic Compressive Behaviour of Magnesium Alloy AZ31B, Trans Tech Publications Ltd., Stafa-Zurich.
  26. Zencker, U. and Clos, R. (1999), "Limiting conditions for compression testing of flat specimens in the split Hopkinson pressure bar", Exper. Mech., 39(4), 343-348. https://doi.org/10.1007/BF02329815
  27. Zhang, Q.B. and Zhao, J. (2013), "A review of dynamic experimental techniques and mechanical behaviour of rock materials", Rock Mech. Rock Eng., 47(4), 1-68.

피인용 문헌

  1. Correlations between the physical and mechanical properties of sandstones with changes of water content and loading rates vol.100, 2017, https://doi.org/10.1016/j.ijrmms.2017.11.005
  2. Effect of water saturation and loading rate on the mechanical properties of Red and Buff Sandstones vol.88, 2016, https://doi.org/10.1016/j.ijrmms.2016.07.005
  3. Numerical simulation of AA7075 under high strain rate with different shape of striker of split Hopkinson Pressure bar vol.26, pp.None, 2015, https://doi.org/10.1016/j.mtcomm.2021.102178
  4. Stress propagation and debonding effects in impedance-graded multi-metallic systems under impact loading vol.12, pp.1, 2015, https://doi.org/10.1177/2041419620917709