This report presents a simple and convenient method to generate nanoscale fractures (cracks) in smooth, single-crystalline Si substrates. The cracks propagated as approximately straight lines along the {100} crystal planes with controllable length defined by a stabilizing backlayer. Close to its tip, the crack presented a vertical offset of the two planes as step of smoothly decreasing height, ...

We study the dynamic fracture of thin layers of suspensions of non-Brownian rigid particles. The impact of a projectile triggers a liquid-to-solid transition and a hole opens in the layer. We show that the occurrence of fracture and the spatial and dynamic features of the cracks depend mostly on the thickness of the layer and the particle volume fraction. In contrast, the properties of the frac...

What is meant by the “inner edge” of an accretion disk around a black hole depends on the property that defines the edge. We discuss four such definitions using data from recent high-resolution numerical simulations. These are: the “turbulence edge”, where flux-freezing becomes more important than turbulence in determining the magnetic field structure; the “stress edge”, where plunging matter l...

Fatigue cracking in metallic aircraft structure often originates at fastener holes and can be detected using the nondestructive inspection technique of bolt-hole eddy-current (BHEC) testing. BHEC testing is based on detection of a disturbance in the induced current or magnetic field caused by a surface-breaking crack in the bore of the hole. However, if the surface of the hole contains benign m...

The Bitter decoration technique is used to study the trapping of single and multiple quanta vortices by a lattice of circular microholes. By keeping a thin superconducting layer (the bottom) inside each hole we are able to visualise the trapped vortices. From this we determine, for the first time, the filling factor FF, i.e. the number of vortices captured inside a hole. In all cases the sample...

A closed-form solution is obtained for the problem of a mode-III interfacial edge crack between two bonded semi-infinite dissimilar elastic strips. A general out-of-plane displacement potential for the crack interacting with a screw dislocation or a line force is constructed using conformal mapping technique and existing dislocation solutions. Based on this displacement potential, the stress in...

This chapter is concerned with cracks . Real cracks in solids are complicated: they are thin cavities, their two faces may touch, and the faces may be rough. We consider ideal cracks. By definition, such a crack is modelled by a smooth open surface Ω (such as a disc or a spherical cap); the elastic displacement is discontinuous across Ω, and the traction vanishes on both sides of Ω (so that the...

This paper is devoted to the problem of thermal fracture a functionally graded coating (FGC) on homogeneous substrate (H), i.e., FGC/H structures. The structure was subjected thermo-mechanical loadings. Systems interacting cracks were located in FGC. Typical such structures include edge cracks, internal and edge/internal cracks. material properties toughness FGC modeled by formulas based rule m...

The evolution of surface damage in bilayers due to cyclic spherical indentation in the presence of incompressible lubricant is studied using an all-transparent glass/polycarbonate system as amodel formore practical applications such as dental crowns and rolling contact fatigue. In situ observations and post-mortem material sectioning reveal that inner cone cracks evolve sequentially from the co...

Edge-type threading dislocations (TDs) can be reduced by increasing the epilayer thickness of undoped AlN grown on c-plane sapphire substrate by low pressure MOVPE. Indium as a surfactant helps to reduce cracks in both, undoped and Si-doped AlN epilayers. For high Si concentrations, edge-type TDs bend and bunch together and finally emerge as V-pits on the epilayer surface. We observed an increa...