Discrete dislocation plasticity analysis of crack-tip fields in polycrystalline materials

DS Balint, VS Deshpande, A Needleman*, E Van Der Giessen

*Bijbehorende auteur voor dit werk

OnderzoeksoutputAcademicpeer review

14 Citaten (Scopus)
262 Downloads (Pure)


Small scale yielding around a mode I crack is analysed using polycrystalline discrete dislocation plasticity. Plane strain analyses are carried out with the dislocations all of edge character and modelled as line singularities in a linear elastic material. The lattice resistance to dislocation motion, nucleation, interaction with obstacles and annihilation are incorporated through a set of constitutive rules. Grain boundaries are modelled as impenetrable to dislocations. The polycrystalline material is taken to consist of two types of square grains, one of which has a bcc-like orientation and the other an fcc-like orientation. For both orientations there are three active slip systems. Alternating rows, alternating columns and a checker-board-like arrangement of the grains is used to construct the polycrystalline materials. Consistent with the increasing yield strength of the polycrystalline material with decreasing grain size, the calculations predict a decrease in both the plastic zone size and the crack-tip opening displacement for a given applied mode I stress intensity factor. Furthermore, slip-band and kink-band formation is inhibited by all grain arrangements and, with decreasing grain size, the stress and strain distributions more closely resemble the HRR fields with the crack-tip opening approximately inversely proportional to the yield strength of the polycrystalline materials. The calculations predict a reduction in fracture toughness with decreasing grain size associated with the grain boundaries acting as effective barriers to dislocation motion.

Originele taal-2English
Pagina's (van-tot)3047-3071
Aantal pagina's25
TijdschriftPhilosophical Magazine
Nummer van het tijdschrift26-27
StatusPublished - sep.-2005
EvenementEmbury Symposium - , Canada
Duur: 1-jun.-2004 → …

Citeer dit