Observatorio de I+D+i UPM

Memorias de investigación
Research Publications in journals:
Computational Issues in the Simulation of Two-dimensional Discrete Dislocation Mechanics.
Year:2007
Research Areas
  • Materials
Information
Abstract
The effect of the integration time step and the introduction of a cut-off velocity for the dislocation motion was analysed in discrete dislocation dynamics ( DD) simulations of a single crystal microbeam. Two loading modes, bending and uniaxial tension, were examined. It was found that a longer integration time step led to a progressive increment of the oscillations in the numerical solution, which would eventually diverge. This problem could be corrected in the simulations carried out in bending by introducing a cut-off velocity for the dislocation motion. This strategy ( long integration times and a cut-off velocity for the dislocation motion) did not recover, however, the solution computed with very short time steps in uniaxial tension: the dislocation density was overestimated and the dislocation patterns modified. The different response to the same numerical algorithm was explained in terms of the nature of the dislocations generated in each case: geometrically necessary in bending and statistically stored in tension. The evolution of the dislocation density in the former was controlled by the plastic curvature of the beam and was independent of the details of the simulations. On the contrary, the steady-state dislocation density in tension was determined by the balance between nucleation of dislocations and those which are annihilated or which exit the beam. Changes in the DD imposed by the cut-off velocity altered this equilibrium and the solution. These results point to the need for detailed analyses of the accuracy and stability of the dislocation dynamic simulations to ensure that the results obtained are not fundamentally affected by the numerical strategies used to solve this complex problem.
International
Si
JCR
Si
Title
MODEL SIMUL MATER SC
ISBN
0965-0393
Impact factor JCR
1,158
Impact info
Volume
15
Journal number
4
From page
S361
To page
S375
Month
JUNIO
Ranking
Participants
  • Autor: I. Romero
  • Autor: Fco. Javier Llorca Martinez (UPM)
  • Autor: Javier Segurado Escudero (UPM)
Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Materiales Estructurales avanzados y nanomateriales
  • Departamento: Ciencia de los Materiales
S2i 2019 Observatorio de investigación @ UPM con la colaboración del Consejo Social UPM
Cofinanciación del MINECO en el marco del Programa INNCIDE 2011 (OTR-2011-0236)
Cofinanciación del MINECO en el marco del Programa INNPACTO (IPT-020000-2010-22)