The relationship between the crack nucleation and stress-induced martensitic transformation in the retained massive austenites (RM’s) of austempered ductile irons (ADIs) was examined in detail by carrying out tensile tests and scanning electron microscope (SEM) observations for an ADI material. The SEM observations revealed that cracks were not nucleated in the peripheral regions of graphite no...

Volumetric images of small mortar cylinders under load are acquired by X-ray microtomography. The images are binarized at different threshold values, and the connected components are extracted at each threshold with a 3D spaceand time-efficient program. Statistics of volume and surface area of separated concrete segments and cracks are collected and analyzed. Under increasing load, the concrete...

We develop in this Note a homogenization method to tackle the problem of a diffusion process through a cracked medium. We assume that the cracks are orthogonal to the surface of the material, where an incoming heat flux is applied. The cracks are supposed to be of depth 1, of small width, and periodically arranged. We show that the cracked surface of the domain induces a volume source term in t...

Models of surface fractures due to volcanic loading of an elastic plate are commonly used to constrain the thickness of planetary lithospheres, but discrepancies exist in predictions of the style of initial failure and in the nature of subsequent fracture evolution. In this study, we perform an experiment to determine the mode of initial failure due to the incremental addition of a conical load...

The resonance phenomenon observed in Rayleigh wave scattering from surface-breaking cracks has been investigated using Freund's results on reflection of Rayleigh waves from an infinite crack edge. To model the crack as a section of acoustic waveguide, resonances are treated as standing waves in the length and depth directions. The model takes both faces of the crack into consideration, and this...

Advanced artificial flaw manufacturing method has become available. The method produces true fatigue cracks, which are representative of most service-induced cracks. These cracks can be used to simulate behaviour of realistic cracks under service conditions. This paper introduces studies of the effects of different thermal loading cycles to crack opening and residual stress state as seen at the...

Corrosion surface damage in the form of pitting and micro-cracks is observed in many metals. Cracks usually initiate from the pits and grow under cyclic stresses and eventually lead to material failure. An image analysis based on wavelet transforms and fractals was used to study the corrosion morphology of nickel aluminum bronze metal under varying corrosion conditions and applied stresses. Ima...

During the fabrication of nanopost arrays for measuring cellular forces, we have observed surface cracks in the negative molds used to replicate the arrays from a silicon master. These cracks become more numerous and severe with each replication such that repeated castings lead to arrays with missing or broken posts. This loss in pattern fidelity from the silicon master undermines the spatial r...