High-speed digital photography was used to study rupture propagation on the interface between transparent damaged and undamaged photoelastic plates. Bilateral ruptures were nucleated on pre-machined faults at an angle α to the uniaxial loading axis. Stress concentration at the crack tips produced fringes in polarized laser light that allowed their positions to be measured in successive photos. ...

During the processing of laminar ceramic, biaxial, residual stresses can arise due to differential thermal contraction between unlike layers. A tensile stress can cause pre-existing flaws to extend across the layer and into the adjacent layers and then tunnel until they meet either another crack or a free surface. A previous analysis has shown that for a given residual stress there is a critica...

To fully utilise the advantageous durability properties of new cementitious materials such as fibre-reinforced Strain-Hardening Cement-based Composites (SHCC), a performance-based durability design approach is required. For crack-free ordinary concrete first promising concepts exist, e.g. the DuraCrete model. However, the parameters of these models, which were quantified for ordinary concrete, ...

Crack propagation in oxide glasses at low crack velocities is controlled by stress corrosion. Proper knowledge of the crack tip chemical environment is thus crucial to understand the slow fracture process of these materials. The formation of a liquid condensate in the confined area of the crack tip is theoretically expected and is classically mentioned to explain specific behavior during the cr...

Tooth enamel is inherently weak, with fracture toughness comparable with glass, yet it is remarkably resilient, surviving millions of functional contacts over a lifetime. We propose a microstructural mechanism of damage resistance, based on observations from ex situ loading of human and sea otter molars (teeth with strikingly similar structural features). Section views of the enamel implicate t...

this experimental study investigated the effects of quenching and tempering heat treatment on fatiguebehavior and also tempering temperature and time holding of aisi 1060 steel. at first, the specimenswere austenitized at 800˚c for 1 hour, and then were quenched in the water bath of 25˚c temperature.after that, tempering process was done at the temperature of 250˚c, 450˚c and 650˚c for 1 and 2 ...

As a natural composite, nacre has an elegant staggered 'brick-and-mortar' microstructure consisting of mineral platelets glued by organic macromolecules, which endows the material with superior mechanical properties to achieve its biological functions. In this paper, a microstructure-based crack-bridging model is employed to investigate how the strength of nacre is affected by pre-existing stru...

One of the crucial steps in the shaft design process is the optimal selection of the material. Two types of shaft steels with improved corrosion resistances, 1.4305 and 1.7225, were investigated experimentally and numerically in this paper in order to determine some of the material characteristics important for material selection in the engineering design process. Ultimate tensile strength and ...

Ti-6Al-4V hour-glass shaped rotating beam specimens with duplex microstructure were processed by electric discharge machining (EDM). A comparatively high peak current of 29A was utilized in order to increase surface roughness for improved osteointegration. High cycle fatigue (HCF) tests were performed in rotating beam loading (R=-1) on these EDM specimens and results were compared with electrol...

The consolidation of colloidal particles in drying colloidal dispersions is influenced by various factors such as particle size and shape, and interparticle potential. The capillary pressure induced by the menisci, formed between the top layer of particles in the packed bed, compresses the bed of particles while the constraints imposed by the boundaries result in tensile stresses in the packing...