New theory for Mode I crack-tip dislocation emission

AbstractThe atomistic processes during fracture of NiAl are studied using a new embedded atom (EAM) potential to describe the region near the crack tip. To provide the atomistically modeled crack tip region with realistic boundary conditions, a coupled finite element - atomistic (FEAt) technique [1] is employed. In agreement with experimental observations, perfectly brittle cleavage is observed for the (110) crack plane. In contrast, cracks on the (100) plane either follow a zig-zag path on (110) planes, or emit dislocations. Dislocation generation is studied in more detail under mixed mode I/II loading conditions.

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The dislocation-free zone at a mode I crack tip

Engineering Fracture Mechanics ◽

10.1016/0013-7944(94)00207-x ◽

1995 ◽

Vol 50 (2) ◽

pp. 165-173 ◽

Cited By ~ 5

Author(s):

Jianqiao Chen ◽

Shigeo Takezono

Keyword(s):

Crack Tip ◽

Mode I ◽

Mode I Crack ◽

Free Zone

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A crack tip driving force model for mode I crack propagation along linear strength gradient: comparison with the sharp strength gradient case

Acta Mechanica ◽

10.1007/s00707-016-1628-z ◽

2016 ◽

Vol 227 (9) ◽

pp. 2683-2702 ◽

Cited By ~ 3

Author(s):

Yi-Bo Shang ◽

Hui-Ji Shi ◽

Zhao-Xi Wang ◽

Guo-Dong Zhang

Keyword(s):

Crack Propagation ◽

Driving Force ◽

Crack Tip ◽

Mode I ◽

Force Model ◽

Mode I Crack ◽

Strength Gradient

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The Asymptotic Elastic-Viscoplastic Field at Mode I Dynamic Propagating Crack-Tip

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.348-349.817 ◽

2007 ◽

Vol 348-349 ◽

pp. 817-820

Author(s):

Zhen Qing Wang ◽

Ji Bin Wang ◽

Wen Yan Liang ◽

Juan Su

Keyword(s):

Crack Tip ◽

Viscosity Coefficient ◽

Plastic Strain Rate ◽

Mode I ◽

Mode I Crack ◽

Moving Crack ◽

Dynamic Propagating ◽

Propagating Crack ◽

Hardening Condition ◽

Elastic Unloading

The viscosity of material is considered at propagating crack-tip. Under the assumption that the artificial viscosity coefficient is in inverse proportion to the power law of the plastic strain rate, an elastic-viscoplastic asymptotic analysis is carried out for moving crack-tip fields in power-hardening materials under plane-strain condition. A continuous solution is obtained containing no discontinuities. The variations of the numerical solution are discussed for mode I crack according to each parameter. It is shown that stress and strain both possess exponential singularity. The elasticity, plasticity and viscosity of material at the crack-tip only can be matched reasonably under linear-hardening condition. The tip field contains no elastic unloading zone for mode I crack.

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