Fracture mechanics of SiGe-nano-sheets using molecular dynamics study: mechanics of monocrystalline versus polycrystalline structure

We investigated the temperature and strain rate dependent fracture strength of defective graphene using molecular dynamics and an atomistic model. This atomistic model was developed by introducing the influence of strain rate and vacancy defects into the kinetics of graphene. We also proposed a novel continuum based fracture mechanics framework to characterize the temperature and strain rate dependent strength of defective sheets. The strength of graphene highly depends on vacancy concentration, temperature, and strain rate. Molecular dynamics simulations, which are generally performed under high strain rates, exceedingly overpredict the strength of graphene at elevated temperatures. Graphene sheets with random vacancies demonstrate a singular stress field as in continuum fracture mechanics. Molecular dynamics simulations on the crack propagation reveal that the energy dissipation rate indicates proportionality with the strength. These findings provide a remarkable insight into the fracture strength of defective graphene, which is critical in designing experimental and instrumental applications.

Download Full-text

A computational study of the mixed-mode crack behavior by molecular dynamics method and the multi-parameter crack field description of classical fracture mechanics

Procedia Structural Integrity ◽

10.1016/j.prostr.2020.01.107 ◽

2019 ◽

Vol 23 ◽

pp. 322-327 ◽

Cited By ~ 1

Author(s):

Stepanova Larisa ◽

Bronnikov Sergey

Keyword(s):

Molecular Dynamics ◽

Fracture Mechanics ◽

Mixed Mode ◽

Computational Study ◽

Molecular Dynamics Method ◽

Crack Behavior ◽

Mixed Mode Crack ◽

Dynamics Method

Download Full-text

Failure Envelope and Fracture Toughness of Kerogen by Molecular Dynamics Simulations: Connecting Molecular-Scale to Micro-Continuum Scale in Fracture Mechanics

10.46427/gold2020.2903 ◽

2020 ◽

Author(s):

Tianhao Wu ◽

Abbas Firoozabadi

Keyword(s):

Molecular Dynamics ◽

Fracture Toughness ◽

Fracture Mechanics ◽

Molecular Dynamics Simulations ◽

Failure Envelope ◽

Molecular Scale ◽

Continuum Scale ◽

Dynamics Simulations

Download Full-text

The α↔γ transformation of an Fe1−xCrx alloy: A molecular-dynamics approach

International Journal of Modern Physics C ◽

10.1142/s0129183116501242 ◽

2016 ◽

Vol 27 (10) ◽

pp. 1650124 ◽

Cited By ~ 5

Author(s):

Emilia Sak-Saracino ◽

Herbert M. Urbassek

Keyword(s):

Molecular Dynamics ◽

Phase Transformation ◽

Transition Temperature ◽

Heterogeneous Nucleation ◽

Md Simulation ◽

Polycrystalline Structure ◽

Impurity Atoms ◽

Austenitic Transformation ◽

Feni Alloys

Using molecular dynamics (MD) simulation, we study the temperature-induced [Formula: see text] phase transformation of an Fe[Formula: see text]Cr[Formula: see text] alloy. We find that the austenitic transition temperature is increased with respect to that of an Fe[Formula: see text]Ni[Formula: see text] alloy containing the same concentration of impurity atoms. During the austenitic transformation, heterogeneous nucleation of close-packed (cp) nuclei leads to a polycrystalline structure. The microstructure formed closely resembles that found in pure Fe and in FeNi alloys.

Download Full-text

Fracture behaviors of pre-cracked monolayer molybdenum disulfide: A molecular dynamics study

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.7.132 ◽

2016 ◽

Vol 7 ◽

pp. 1411-1420 ◽

Cited By ~ 11

Author(s):

Qi-lin Xiong ◽

Zhen-huan Li ◽

Xiao-geng Tian

Keyword(s):

Molecular Dynamics ◽

Fracture Mechanics ◽

Size Effect ◽

Molybdenum Disulfide ◽

Fracture Strength ◽

Finite Size ◽

Dynamics Simulation ◽

Finite Size Effect ◽

Fracture Behaviors ◽

Continuum Fracture Mechanics

The fracture strength and crack propagation of monolayer molybdenum disulfide (MoS2) sheets with various pre-existing cracks are investigated using molecular dynamics simulation (MDS). The uniaxial tensions of pre-cracked monolayer MoS2 sheets with different crack tips, different locations of crack, different crack lengths and angled cracks are simulated and studied. The results show that the configuration of crack tip can influence significantly the fracture behaviors of monolayer MoS2 sheets while the location of crack does not influence the fracture strength. With the increase of crack length, the fracture strength of monolayer MoS2 sheets reduces almost linearly, and the fracture of monolayer MoS2 sheets is transformed from almost brittle to ductile. By making comparison between the MDS results and the predictions of continuum fracture mechanics theories, including Inglis' model, Griffith's model with and without finite size effect, it is found that MDS results agree well with the predictions of Griffith's model with finite size effect, differ from the predictions of Inglis' model and Griffith's model without finite size effect. Finally, the MDS results of monolayer MoS2 sheets with different angled crack are also analyzed based on the continuum fracture mechanics model.

Download Full-text