The resistance of high-angle grain boundaries to cleavage cracking in Fe–3wt.%Si bicrystals is discussed in context of linear elastic fracture mechanics based on an energy method. The grain boundary toughness is determined by the fracture work associated with the plastic shear along the grain boundary and the crack-trapping effect. The influence of the crystallographic misorientation and the si...

Hydroacoustic data from the eastern equatorial Pacific reveal low-magnitude seismicity concentrated at the propagating tip of the Galapagos Rise in Hess Deep. The patterns of seismicity and faulting are similar to those observed in the process zone of laboratory-scale propagating tensile cracks. Because the fracture energy required for propagation scales with crack length and process zone size,...

The stability of a rapid dynamic crack in a two-dimensional infinite strip is studied in the framework of linear elastic fracture mechanics supplemented with a modified principle of local symmetry. It is predicted that a single crack becomes unstable by a finite wavelength oscillatory mode at a velocity vc, 0.8cR<vc<0.85cR, where cR is the Rayleigh wave speed. The relevance of this theoretical ...

Experiments of pure tensile fracture in thin brittle gels reveal a new dynamic oscillatory instability whose onset occurs at a critical velocity, VC=0.87CS, where CS is the shear wave speed. Until VC, crack dynamics are well described by linear elastic fracture mechanics (LEFM). These extreme speeds are obtained by suppression of the microbranching instability, which occurs when sample thicknes...

This paper presents a new method for continuum based shape sensitivity analysis for a crack in a homogeneous , isotropic, and linear-elastic body subject to mixed-mode (modes I and II) loading conditions. The method is based on the material derivative concept of continuum mechanics, domain integral representation of an interaction integral, and direct differentiation. Unlike virtual crack exten...

The elastic properties and fracture of two-dimensional graphene were calculated purely from the atomic bonding (stretching and bending) based on molecular mechanics method. Considering the representative unit cell of graphene under various loading conditions, the deformations of carbon bonds and the variations of the interlayer distance could be realized numerically under the geometry constrain...