Crack tip shielding by dislocations is an essential feature of the modeling of semi-brittle crack propagation and the brittle to ductile transition. The stress field, in the elementary configuration where a single dislocation interacts with a crack, is obtained by two independent methods, at two dif
Shielding of crack tips by inclined pileups of dislocations
โ Scribed by C.S. Pande; R.A. Masumura; Y.T. Chou
- Publisher
- Elsevier Science
- Year
- 1988
- Weight
- 577 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0001-6160
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โฆ Synopsis
A mathematical formulation is developed for a long crack (mode III) with two symmetrical screw dislocation pileups inclined to the crack by an angle 4. Dislocation free zones (DFZ) are allowed at the crack up. The resulting series of equations are solved numerically. The effect of the inclination angle r$ on the interaction of the crack and the pileups and on the size of the DFZ is examined. These effects appear to be strongest around 4 = 45". R6snnt~Nous developpons une formulation mathimatique pour une longue fissure (du mode III) avec deux empilements symttriques de dislocations vis inclines d'un angle 4 par rapport d la fissure. Des zones sans dislocations sont auto&es en tZte de fissure. Nous resolvons numeriquement les ensembles d'equations correspondants. Nous examinons l'effet de l'angle d'inclinaison sur l'interaction de la fissure et des empilements, ainsi que sur les dimensions de la zone sans dislocations. Ces effets semblent plus marques autour de I#I = 45". Zusanunenfaasung-Es wird eine mathematische Rehandhmg eines langen Risses (Mode III) vorgelegt, an dem zwei symmetrische, unter dem Winkel 4 zum RiB geneigte Aufstauungen liegen. An der Rigspitze werden versetzungsfreie Zonen zugelassen. Die sich ergebenden Gleichungsserien werden numerisch
๐ SIMILAR VOLUMES
In this paper, a unified mechanics model for dislocation nucleation, emission and dislocation free zone is proposed based on the Peierls framework. Three regions are identified ahead of the crack tip. The emitted dislocations within the plastic zone in the form of an inverse pile up are treated as d