We use computer simulations to study the behavior of atomically sharp and blunted cracks in various f.c.c. metals. The simulations use effective medium potentials which contain many-body interactions. We find that when using potentials representing platinum and gold a sharp crack is stable with respect to the emission of a dislocation from the crack tip, whereas for all other metals studied the...

We have carried out systematic fracture experiments in a single edge notch geometry over a range of stretch rates on dual crosslink hydrogels made from polyvinyl alcohol chains chemically crosslinked with glutaraldehyde and physically crosslinked with borate ions. If the energy release rate necessary for crack propagation was calculated conventionally, by using the work done to deform the sampl...

Static fatigue behavior is the main failure mode of optical fibers applied in sensors. In this paper, a computational framework based on continuum damage mechanics (CDM) is presented to calculate the crack propagation process and failure time of optical fibers subjected to static bending and tensile loads. For this purpose, the static fatigue crack propagation in the glass core of the optical f...

We present a combined novel methodology to study the three-dimensional complex geometry of a tortuous crack and identify the essential features of the crack and its propagation inside a heterogeneous material. We find that some severe damage events occur unexpectedly below a local mode-I crack within the sample; we realize that the severe plastic zone of the local mode-I crack is shifted down b...

In this study, the pitting type of corrosion growth characteristics, fatigue crack initiation and propagation behavior; axial fatigue tests were carried out on precipitation hardened martensitic Custom 450 steel in the air and 3.5wt% NaCl solution. Using the ratio of the depth to the half-width of the pits; (a/c)= 1.5±0.2 the corrosion pit depth growth law was obtained as a function of stress a...

Fatigue crack initiation and early short crack propagation behaviour in two microstructural variants of a recently developed Low Solvus, High Refractory (LSHR) disc superalloy at room temperature has been investigated by three-point bending with replication procedure. The results shows that fine gained (FG) LSHR possesses higher fatigue life due to its better crack initiation resistance, limite...

the cracked brazilian disc (cbd) specimen is widely used in order to determine mode-i/ii and mixed-mode fracture toughness of a rock medium. in this study, the stress intensity factor (sif) on the crack-tip in this specimen is calculated for various geometrical crack conditions using the extended-finite element method (x-fem). this method is based upon the finite element method (fem). in this m...

A controlled crack growth was achieved in single edge—cracked specimens made of a high—molecular weight PNNA by regulating the cross— head speed of loading of the specimens by a computer—driven testing device. The crosshead speeds used during the tests were varied between v =1x107m/s and 1X1O5m/s. 5 It was shown that in this area of very slow quasi—static loading of brittle plexiglas specimens ...

Fatigue properties and cracking behavior of cold-drawn commercially pure aluminum wires (CPAWs) widely used as the overhead transmission conductors were investigated. It was found that the fracture surface of the CPAWs shows an obvious four-stage fracture characteristic, i.e., crack initiation, planar crack propagation, 45°-inclined crack propagation and final rapid fracture. The crack growth m...

Using molecular dynamics with an accurate many-body potential for metallic Tantalum, we studied crack propagation in a pre-notched nano-slab under uniaxial strain in a [100] direction. We study dislocation emission from the crack tip for various strain rate and temperatures and focus on the inuence of the local temperature at the crack tip on the nature of the crack propagation We nd a close co...