The energetics of dislocations accelerating and decelerating through the shear-wave speed barrier

Markenscoff, Xanthippi; Huang, Surong
January 2009
Applied Physics Letters;1/12/2009, Vol. 94 Issue 2, pN.PAG
Academic Journal
The question of whether a dislocation can accelerate through the shear-wave speed “barrier” is addressed by analyzing the transient motion at the instant when the velocity equals the shear-wave speed in the presence of acceleration. The stresses carried by the forming Mach wave fronts depend on the acceleration at this instant, and the energy required to push the dislocation through the shear-wave speed barrier is determined by means of the “contour-independent” dynamic J integral, which defines the self-force on a moving defect, and is obtained as a function of the acceleration as it crosses the barrier. For decelerating motion through the shear-wave speed barrier this energy is released as dissipation.


Related Articles

  • Activation volume and density of mobile dislocations in plastically deforming nanocrystalline Ni. Wang, Y. M.; Hamza, A. V.; Ma, E. // Applied Physics Letters;6/13/2005, Vol. 86 Issue 24, p241917 

    We report the analysis of repeated transients to monitor the coupled evolution of dislocation velocity and mobile dislocation density in plastically deforming nanocrystalline Ni. The stress relaxation series allowed the determination of the physical activation volume, indicating a...

  • DILATATION AND DISTORTIONAL WAVES IN MICRO-ISOTROPIC, MICRO-ELASTIC MEDIUM. Chandulal, A.; Sambaiah, K. // Bulletin of Pure & Applied Sciences-Mathematics;2010, Vol. 29E Issue 2, p309 

    In this paper, the propagation of dilatation and distortional waves in micro-isotropic, microelastic medium has been discussed. Frequency equations have been deduced in both the cases. It is found that additional waves are propagating in the medium. The classical results are obtained as a...

  • The Dependence of Anomalous Temperature Peak of a Deforming Stress on Microstructural Parameters. Petukhov, B. V. // Crystallography Reports;May2001, Vol. 46 Issue 3, p474 

    The temperature dependence of a deforming stress (including both low-temperature decreasing branch and an anomalous high-temperature peak) has been calculated on the basis of one mechanism. The theory developed takes into account spontaneous thermally activated processes of dislocation locking...

  • The elastic field associated with a square dislocation loop in a two-phase medium. Jagannadham, K.; Narayan, J. // Journal of Applied Physics;9/1/1987, Vol. 62 Issue 5, p1698 

    Focuses on a study which presented the surface dislocation analysis of the three-dimensional distortion associated with a prismatic square dislocation loop in a two-phase medium. Background on the analysis of the elastic field associated with a dislocation loop; Geometry of the square loop in...

  • Effects of residual surface stress and surface elasticity on the nonlinear free vibration of nanoscale plates. Wang, K. F.; Wang, B. L. // Journal of Applied Physics;Jul2012, Vol. 112 Issue 1, p013520 

    This paper studies the influence of surface effects (including the residual surface stress and surface elasticity) on the nonlinear free vibrations of nanoscale plates. The motion equations are derived by using the Hamilton's principle and solved numerically. It is found that the influence of...

  • Wave propagation in assemblies of cemented spheres. Evans, T. Matthew; Ning, Zhangwei // AIP Conference Proceedings;Jun2013, Vol. 1542 Issue 1, p233 

    Wave velocity through granular assemblies is an important measure of system stiffness and an indicator of response at small strains. In the laboratory, shear wave velocity is often measured using piezoelectric bender elements to induce and receive waves across a specimen. Shear wave velocity is...

  • NON-LINEAR TRANSVERSE VIBRATIONS and 3:1 INTERNAL RESONANCES OF A TENSIONED BEAM ON MULTIPLE SUPPORTS. Bağdatlı, S.Murat; Öz, H. Rıdvan; Özkaya, Erdoğan // Mathematical & Computational Applications;2011 Special Issue, Vol. 16 Issue 1, p203 

    In this study, nonlinear transverse vibrations of a tensioned Euler-Bernoulli beam resting on multiple supports are investigated. The immovable end conditions due to simple supports cause stretching of neutral axis and introduce cubic nonlinearity to the equations of motion. Forcing and damping...

  • On the foundations of stochastic dislocation dynamics. Hähner, P. // Applied Physics A: Materials Science & Processing;1996, Vol. 62 Issue 5, p473 

    A stochastic approach to dislocation dynamics is proposed that starts off from considering the geometrically necessary fluctuations of the local stress and strain rate caused by long-range dislocation interactions during plastic flow. On a mesoscopic scale, a crystal undergoing plastic...

  • Modelling plasticity using strain nuclei: discretization of the dislocation field by uniform triangles. Hills, D A; McKellar, D K; Sackfield, A // Journal of Strain Analysis for Engineering Design (Professional ;Mar2003, Vol. 38 Issue 2, p95 

    The solution is given for the state of stress induced in an infinite plane by a uniform distribution of edge dislocations present over a general triangle. This provides the basis of a 'perturbation element' for modelling macroscopic plastic flow, providing a systematic and internally consistent...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics