The crack initiation and short propagation in a martensitic spring steel were investigated by means of in-situ fatigue testing. Shot peened samples as well untreated exposed to uniaxial alternating stress analyze the impact compressive residual stresses. early damage started both sample conditions with formation slip bands, which subsequently served sites. Most bands and, correspondingly, most ...

Nickel-base superalloys have become the key materials of hot-end components in the aeroengines over the past several decades. Nickelbase superalloys are easy to produce thermo-mechanical fatigue (TMF) behavior when withstanding the combined effects of high temperature, creep, oxidation, mechanical stress and thermal stress. The occurrence of TMF seriously affects the normal service for hot-end ...

Catastrophic failure of any brittle structure under dynamic loading consists of dynamic crack initiation, propagation, curving, branching (both micro and macro) and branching instability. However, the failure is much more complex in case of layered materials which has interfaces. In these materials, other than above crack mechanisms the crack can also deflect to propagate along the interface or...

interactive effect of plant growth regulators6-benzylaminopurine (bap) (0, 2, 4 and 8 µm) and1-naphtalene acetic acid (naa) (0, 0.05, 0.25 and 0.5µm) in van der salm (vs) medium was used to optimize in vitro propagation of rosa hybrida cv. iceberg.shoot proliferation and number of new leaves weremeasured as growth indicators. as the concentrationof bap was raised, growth rate increased with all...

A liquid droplet resting on a soft gel substrate can deform that substrate to the point of material failure, whereby fractures develop on the gel surface that propagate outwards from the contact line in a starburst pattern. In this paper, we characterize (i) the initiation process, in which the number of arms in the starburst is controlled by the ratio of the surface tension contrast to the gel...

In this article a new fretting fatigue life prediction model is presented. The can be classified as variable crack initiation length: the and propagation phases are calculated function of length, among all feasible lengths orientations, that producing minimum considered. proposal direction automatically determined parameters in both phases: propagation. applied to wide experimental campaign tes...

Nowadays modification of metallic biomaterials which are used as implants for bone and hard tissues replacement is considered as an important subject. In the current study, corrosion fatigue properties of Ti-6Al-4V alloy investigated via Rotating-Bending standard test method and then, the results compared with the fatigue properties of the specimens tested in the same conditions. Scanning elect...

The dynamic mode-I energy release rate of cracks propagating along elastic interfaces in double cantilever beams under high loading rates is derived analytically for the first time by accounting structural vibration, wave propagation, and Doppler effect with assumption crack tip conservation. developed theory can be used to study “stick-slip” propagation behavior commonly observed experiments, ...