Discrete Dislocation Dynamics Study on Distribution of Dislocations and Stress Field near Crack Tip

1998 ◽  
pp. 143-154 ◽  
Author(s):  
Akihiro Nakatani ◽  
Hiroshi Kitagawa ◽  
Makoto Sugizaki
Keyword(s):  
Stress Field ◽  
Crack Tip ◽  
Dislocation Dynamics ◽  
Discrete Dislocation Dynamics ◽  
Discrete Dislocation ◽  
Distribution Of Dislocations

scholarly journals First Steps of Crack Initiation and Propagation in Fatigue of FCC Crystals Studied by Dislocation Dynamics

2012 ◽  
Author(s):  
C. Déprés ◽  
G. V. Prasad Reddy ◽  
L. Tabourot ◽  
R. Sandhya ◽  
S. Sankaran
Keyword(s):  
Stress Field ◽  
Crack Initiation ◽  
Crack Propagation ◽  
Fatigue Crack Initiation ◽  
Crack Tip ◽  
Dislocation Dynamics ◽  
Crack Initiation And Propagation ◽  
Dislocation Dynamic ◽  
Discrete Dislocation ◽  
Initiation And Propagation

3D discrete dislocation dynamic (DDD) simulations are performed to simulate stage-I fatigue crack initiation and propagation along the surface, in the primary grain and its neighbouring grain, in 316L stainless steel. The scenario of crack propagation in primary grain and the evolution of dislocation structure ahead of crack tip are discussed, and in addition crack tip sliding displacement is estimated. Probable mechanisms of crack propagation from primary grain to neighbouring grain are evaluated. In this process, surface relief in the neighbouring-grain under the influence of crack stress field in the primary grain is studied for varying neighbouring-grain orientations. An enhanced evolution of surface extrusions in the neighbouring grain, are observed in the presence of heterogeneous stress field (i.e., in the presence of crack in the primary grain), compared to that in the case of homogeneous stress field. In addition, influence of crack stress field on prior cyclic-deformed substructure is presented.

Crack Tip Plasticity By Classic Dislocation Dynamics

2008 ◽  
Vol 33-37 ◽  
pp. 97-102
Author(s):  
Hiroomi Homma ◽  
Huu Nhan Tran
Keyword(s):  
Short Pulse ◽  
Crack Tip ◽  
Plastic Zone Size ◽  
Dislocation Dynamics ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Discrete Dislocation Dynamics ◽  
Discrete Dislocation ◽  
Crack Tip Plasticity ◽  
Crack Tip Opening

Under very short pulse loads in range from 25 to 100 μs, crack tip plasticity a head of the crack tip in the mode I condition was investigated by discrete dislocation dynamics. The obtained dislocation array parameters such as the number of dislocations, dislocation distribution density, crack tip opening displacement and plastic zone size increase with the magnitude of stress intensity factor, KI and pulse durations. The numerical results were well compared with the experimental ones.

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