Issue 38

M. Sokovikov et alii, Frattura ed Integrità Strutturale, 38 (2016) 296-304; DOI: 10.3221/IGF-ESIS.38.40 303 In Fig. 13 shown results of 3D simulation, which was made using ABAQUS. Numerical simulations allowed us to determine temperature distribution on the back surface of the target during the process of plug formation and ejection, Fig.14. Temperature fields on the back surface of the sample during the process of plug formation and ejection are close to those found experimentally. Figure 14 : Time evolution of temperature distribution on the back surface of the sample. C ONCLUSIONS heoretical study and original experimental data allow us to suggest that one of the mechanisms of plastic shear instability and plastic strain localization observed in the high-speed loading tests is caused by the collective multiscale behavior in the microshear ensembles qualified as non-equilibrium structural-scaling transition. This mechanism leads to the pronounced structural relaxation leading to the plastic strain localization and is independent on conventionally used assumption concerning the autocatalytic temperature effect on the viscosity decrease. Structural analysis of material in the strain localization area supported this mechanism of structural relaxation and the influence on strain localization as the precursor of adiabatic shear band formation. A CKNOWLEDGMENTS his study was supported by the Russian Science Foundation, project No. 14-19-01173. R EFERENCES [1] Grady, D.E., Dynamic of adiabatic shear. Journal de Physique IV, Colloque C3, suppl. au Journal de Physique III, 1, (1991) 653-660. [2] Meyer, L.W., Staskewitsch E., Burblies A. Adiabatic shear failure under biaxial dynamic compression/shear loading. Mech. Mater., 17(2-3) (1994) 203-214. [3] Naimark, O.B., Kinetic transition in ensembles of microcracks and some nonlinear aspects of fracture, In: Proc. IUTAM Symposium on nonlinear analysis of fracture. Cambridge, United Kingdom, (1995) 285-298. [4] Naimark, O.B., Collective properties of mesodefect ensembles and some nonlinear plasticity and failure problems. Physical Mesomechanics, 6 (2004) 45-72. [5] Rittel, D., Landau, P., Venkert, A., Dynamic Recrystallization as a Potential Cause for Adiabatic Shear Failure, Phys.Rev.Lett., 101 (2008) 165501. [6] Sokovikov, M.A., Chudinov, V.V., Uvarov, S.V., Plekhov, O.A., Lyapunova, E.A., Petrova, A.N., Bayandin, Yu.V., Naimark, O.B., Brodova, I.G., PNRPU Mechanics Bulletin, 2 (2013) 154-175. T T