Ductile-Brittle Behavior of Microcracks in 3D

2005 ◽  
Vol 482 ◽  
pp. 131-134
Author(s):  
V. Pelikán ◽  
Petr Hora ◽  
Anna Machová ◽  
Michal Landa
Keyword(s):  
Molecular Dynamics ◽  
Crack Initiation ◽  
Mode I ◽  
Dislocation Emission ◽  
Brittle Behavior ◽  
Free Sample ◽  
Bcc Iron ◽  
Parallel Molecular Dynamics

Results of several parallel molecular dynamics crack simulations in bcc iron crystals with up to 128 million atoms are presented. The crack (001)[010] of Griffith type is loaded in Mode I. We observe dislocation emission and twinning near the free sample surfaces and later plastically induced crack initiation.

Effects of Temperature on Crack Propagation of Nanocrystalline Nickel: A Molecular Dynamics Approach

2014 ◽  
Vol 926-930 ◽  
pp. 98-102
Author(s):  
Zi Qiang Li ◽  
Jin Gui Yu ◽  
Qiao Xin Zhang
Keyword(s):  
Molecular Dynamics ◽  
Crack Propagation ◽  
Great Influence ◽  
Crack Tip ◽  
Md Simulations ◽  
Mode I ◽  
Dislocation Emission ◽  
Nanocrystalline Nickel ◽  
Atomic Lattice ◽  
Effects Of Temperature

The primary purpose of this paper is to study the effects of temperature on crack propagation of nanocrystalline nickel by Molecular Dynamics (MD) simulations. Cracks are loaded in tension mode I. Results show that dislocation emission from a crack tip in nanocrystalline nickel due to the recombination of atomic lattice, then distortion of the crack tip promote crack propagation. The studies we have performed showed that temperature takes a great influence on the crack propagation and the crack shape, and we also found that the crack blunt obviously at high temperature.

Crack Orientation versus Ductile-Brittle Behavior in 3D Atomistic Simulations

2007 ◽  
Vol 567-568 ◽  
pp. 61-64 ◽  
Author(s):  
Alena Spielmannová ◽  
Anna Machová ◽  
Petr Hora
Keyword(s):  
Room Temperature ◽  
Md Simulations ◽  
Atomistic Simulations ◽  
Mode I ◽  
Crack Plane ◽  
Crack Orientation ◽  
Brittle Behavior ◽  
Bcc Iron ◽  
Fracture Tests ◽  
Recent Fracture

The paper presents results of molecular dynamic (MD) simulations in 3D bcc iron crystals with edge pre-existing cracks (001)[110] and (110) [110] (crack plane/crack front) loaded uni-axially in tension mode I at temperature of 300 K. The iron crystals in MD have the same orientation and similar geometry as in our recent fracture tests performed at room temperature on iron (3wt.%Si) single crystals [1].

Ductile-Brittle Behavior along Crack Front and T-Stress

2011 ◽  
Vol 465 ◽  
pp. 69-72
Author(s):  
Alena Uhnáková ◽  
Anna Machová ◽  
Petr Hora
Keyword(s):  
Stress Analysis ◽  
Molecular Dynamic ◽  
Crack Front ◽  
Crystallographic Orientation ◽  
Md Simulations ◽  
Mode I ◽  
Brittle Behavior ◽  
Bcc Iron ◽  
T Stress ◽  
The Continuum

We present new results of molecular dynamic (MD) simulations in 3D bcc iron crystals with embedded central through crack (001)[110] of Griffith type loaded in mode I. Two different sample geometries of the same crystallographic orientation were tested with negative and positive values of the T-stress, which change the ductile-brittle behavior along the crack front in 3D. This phenomenon is explained in the framework of stress analysis, both on the continuum and atomistic level.

Sample Geometry and the Brittle-Ductile Behavior of Edge Cracks in 3D Atomistic Simulations by Molecular Dynamics

2016 ◽  
Vol 258 ◽  
pp. 45-48 ◽  
Author(s):  
Vladimír Pelikán ◽  
Petr Hora ◽  
Anna Machová ◽  
Radek Kolman ◽  
Alena Uhnáková
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamic ◽  
Md Simulations ◽  
Atomistic Simulations ◽  
Mode I ◽  
Sample Geometry ◽  
Bcc Iron ◽  
T Stress ◽  
Edge Cracks ◽  
Ductile Behavior

We present new results of molecular dynamic (MD) simulations in 3D bcc iron crystals with edge cracks (001)[010] and (-110)[110] loaded in mode I. Different sample geometries of SEN type were tested with negative and positive values of T-stress according to continuum prediction by Fett.

Ductile–brittle behavior at the (110)[001] crack in bcc iron crystals loaded in mode I

2010 ◽  
Vol 77 (2) ◽  
pp. 184-192 ◽  
Author(s):  
J. Prahl ◽  
A. Machová ◽  
A. Spielmannová ◽  
M. Karlík ◽  
M. Landa ◽  
...  
Keyword(s):  
Mode I ◽  
Brittle Behavior ◽  
Bcc Iron

Cleavage Planes of Icosahedral Quasicrystals: A Molecular Dynamics Study

2003 ◽  
Vol 805 ◽  
Author(s):  
Frohmut Rösch ◽  
Christoph Rudhart ◽  
Peter Gumbsch ◽  
Hans-Rainer Trebin
Keyword(s):  
Molecular Dynamics ◽  
Brittle Fracture ◽  
Crack Propagation ◽  
Three Dimensional ◽  
Propagation Direction ◽  
Mode I ◽  
Dynamic Crack ◽  
Fracture Surfaces ◽  
Icosahedral Quasicrystals ◽  
Crack Tip Plasticity

ABSTRACTThe propagation of mode I cracks in a three-dimensional icosahedral model quasicrystal has been studied by molecular dynamics techniques. In particular, the dependence on the plane structure and the influence of clusters have been investigated. Crack propagation was simulated in planes perpendicular to five-, two- and pseudo-twofold axes of the binary icosahedral model.Brittle fracture without any crack tip plasticity is observed. The fracture surfaces turn out to be rough on the scale of the clusters. These are not strictly circumvented, but to some extent cut by the dynamic crack. However, compared to the flat seed cracks the clusters are intersected less frequently. Thus the roughness of the crack surfaces can be attributed to the clusters, whereas the constant average heights of the fracture surfaces reflect the plane structure of the quasicrystal. Furthermore a distinct anisotropy with respect to the in-plane propagation direction is found.

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