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Journal of Applied Mechanics and Technical Physics

, Volume 59, Issue 7, pp 1179–1188 | Cite as

Numerical Simulation and Experimental Study of Plastic Strain Localization under the Dynamic Loading of Specimens in Conditions Close to a Pure Shear

  • D. A. BilalovEmail author
  • M. A. Sokovikov
  • V. V. Chudinov
  • V. A. Oborin
  • Yu. V. Bayandin
  • A. I. Terekhina
  • O. B. Naimark
Article
  • 10 Downloads

Abstract

Mechanisms of plastic strain localization under the dynamic loading of specially shaped specimens made of the AMg6 aluminum alloy and intended for tests under conditions close to a pure shear on a split Hopkinson–Kolsky pressure bar are studied theoretically and experimentally. The mechanisms of plastic flow instability are related to collective effects in the ensemble of microdefects in spatially localized regions visualized in situ using a CEDIP Silver 450M high-speed infrared camera. The calculation corresponding to the experimental loading scheme is implemented using wide range constitutive equations reflecting the dependence of structural relaxation mechanisms—manifestation of the collective behavior of microdefects—on the evolution of the localized flow shear instability. Microstructure analysis of deformed specimens included the study of the spatial relief (porosity) scaling by the data of a NewView-5010 microscope-interferometer in regions of plastic strain localization. An increase in the structural scaling exponent (Hurst exponent) reflected the degree of the multiscale correlated behavior of defects and the porosity induced by them in regions of localized plasticity. Infrared scanning of the strain localization region and numerical simulation followed by an estimate of the defect structure corroborated the hypothesis that effects of thermal softening do not play a decisive role in the process of plastic shear localization in the tested material under the considered loading regimes. A new, one of the possible ones, mechanism of plastic strain localization under dynamic loading is justified. It is caused by the multiscale collective behavior of mesodefects—structure-scaling transitions—and establishes the stadiality of the localized shear evolution.

Keywords

numerical simulation plastic shear localization microdefects dynamic loading 

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References

  1. 1.
    Giovanola, J.H., Adiabatic shear banding under pure shear loading. Part I: direct observation of strain localization and energy dissipation measurements, Mech. Mater., 1988, vol. 7, no. 1, pp. 59–71.  https://doi.org/10.1016/0167-6636(88)90006-3 CrossRefGoogle Scholar
  2. 2.
    Marchand A. and Duffy J., An experimental study of the formation process of adiabatic shear bands in a structural steel, J. Mech. Phys. Solids, 1988, vol. 36, no. 3, pp. 251–283.  https://doi.org/10.1016/0022-5096(88)90012-9 ADSCrossRefGoogle Scholar
  3. 3.
    Nemat-Nasser, S., Li, Y.-F., and Isaacs, J.B., Experimental/computational evaluation of flow stress at high strain rates with application to adiabatic shear banding, Mech. Mater., 1994, vol. 17, nos. 2–3, pp. 111–134.  https://doi.org/10.1016/0167-6636(94)90053-1 CrossRefGoogle Scholar
  4. 4.
    Bai, Y., Xuc, Q., Xu, Y., and Shen, L., Characteristics and microstructure in the evolution of shear localization in Ti-6 Al-4V alloy, Mech. Mater., 1994, vol. 17, nos. 2–3, pp. 155–164.  https://doi.org/10.1016/0167-6636(94)90056-6 CrossRefGoogle Scholar
  5. 5.
    Wright, T.W. and Ravichandran, G., Canonical aspects of adiabatic shear bands, Int. J. Plast., 1997, vol. 13, no. 4, pp. 309–325.  https://doi.org/10.1016/S0749-6419(97)80002-2 CrossRefzbMATHGoogle Scholar
  6. 6.
    Molinari, A. and Clifton, R.J., Analytical characterization of shear localization in thermoviscoplastic materials, J. Appl. Mech., 1987, vol. 54, no. 4, pp. 806–812.  https://doi.org/10.1115/1.3173121 ADSCrossRefzbMATHGoogle Scholar
  7. 7.
    Rittel, D., Landau, P., and Venkert, A., Dynamic recrystallization as a potential cause for adiabatic shear failure, Phys. Rev. Lett., 2008, vol. 101, p. 165501.  https://doi.org/10.1103/PhysRevLett.101.165501 ADSCrossRefGoogle Scholar
  8. 8.
    Burns, T.J., Does a shear band result from a thermal explosion?, Mech. Mater., 1994, vol. 17, nos. 2–3, pp. 261–271.  https://doi.org/10.1016/0167-6636(94)90064-7 CrossRefGoogle Scholar
  9. 9.
    Naimark, O.B., Collective properties of defects ensembles and some nonlinear problems of plasticity and fracture, Phys. Mesomech., 2003, vol. 6, no. 4, pp. 39–63.MathSciNetGoogle Scholar
  10. 10.
    Naimark, O.B., Bayandin, Yu.V., Sokovikov, M.A., Plekhov, O.A., Uvarov, S.V., Bannikov, M.V., and Chudinov, V.V., Specimen for shear test (variants) and test method for it, RF Patent, no. 2011,114,711/28, Byull. Izobret., 2013.Google Scholar
  11. 11.
    Mashinostroenie. Entsiklopediya. Tsvetnye metally i splavy. Kompozitsionnye metallicheskie materialy (Mechanical Engineering, Encyclopedia, Vol. II-3: Non-Ferrous Metals and Alloys. Composite Metallic Materials), Moscow: Mashinostroenie, 2001.Google Scholar
  12. 12.
    Bilalov, D.A., Sokovikov, M.A., Chudinov, V.V., Oborin, V.A., Bayandin, Yu.V., Terekhina, A.I., and Naimark, O.B., Study of plastic shear localization in aluminum alloys under dynamic loading, Vychisl. Mekh. Splosh. Sred, 2015, vol. 8, no. 3, pp. 319–328. https://doi.org/doi10.7242/1999-6691/2015.8.3.27 Google Scholar
  13. 13.
    Bouchaud, E., Scaling properties of cracks, J. Phys.: Condens. Matter, 1997, vol. 9, no. 21, pp. 4319–4344.  https://doi.org/10.1088/0953-8984/9/21/002 ADSGoogle Scholar
  14. 14.
    Oborin, V.A., Bannikov, M.V., Naimark, O.B., and Palin-Luc, T., Scaling invariance of fatigue crack growth in gigacycle loading regime, Tech. Phys. Lett., 2010, vol. 36, no. 11, pp. 1061–1064.ADSCrossRefGoogle Scholar

Copyright information

© Pleiades Publishing, Inc. 2018

Authors and Affiliations

  • D. A. Bilalov
    • 1
    Email author
  • M. A. Sokovikov
    • 1
  • V. V. Chudinov
    • 1
  • V. A. Oborin
    • 1
  • Yu. V. Bayandin
    • 1
  • A. I. Terekhina
    • 1
  • O. B. Naimark
    • 1
  1. 1.Institute of Continuous Media Mechanics, Ural BranchRussian Academy of SciencesPermRussia

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