In this paper, we report on an experimental study of spontaneous, mixed-mode, crack propagation in weakly bonded similar and dissimilar materials. A unique experimental configuration is proposed to induce spontaneous crack growth events along the interfaces. The cracks nucleate from tiny circular holes and are triggered by an exploding wire. They subsequently propagate under the action of a con...

Crack propagation in brittle materials with anisotropic surface energy is important in applications involving single crystals, extruded polymers, or geological and organic materials. Furthermore, when this anisotropy is strong, the phenomenology of crack propagation becomes very rich, with forbidden crack propagation directions or complex sawtooth crack patterns. This problem interrogates funda...

Fracture of ceramic materials has been one of the most frequently reported complications for all-ceramic restorations. The aim of the study was to analyze the fracture features of hot-pressed ceramic crowns in order to evaluate areas susceptible to crack initiation and crack propagation correlated with stress areas. The crowns were inspected visually to determine the shape and orientation of th...

Fatigue crack growth was investigated in a 001 1⁄2 oriented single crystal specimen, made of a Ni-based superalloy, Haynes 230. Crack propagation was characterized with digital image correlation: crack closure, measured by analyzing the relative displacements of crack flanks, showed closure levels much lower than polycrystal alloys. Reversed plastic zones were calculated from regressed stress i...

The mechanisms of fatigue-crack propagation in ceramics and intermetallics are examined through a comparison of cyclic crack-growth behavior in ductile and brittle materials. Crack growth is considered to be a mutual competition between intrinsic mechanisms of crack advance ahead of the crack tip, which promote crack growth, and extrinsic mechanisms of crack-tip shielding behind the tip, which ...

In this thesis an investigation and modelling of the fatigue crack propagation in the nickel based superalloy Inconel 718, with a special emphasis on the effect of hold times, is presented. The modelling work has been concentrated on describing the hold time fatigue crack propagation by using the concept of a damaged zone in front of the crack tip, which is believed to have a lowered resistance...

190 Abstract In this paper, a new analytical method for solving stable crack propagation problems in a ductile panel with a row of cracks, is presented. The main purpose of the present study is to estimate the maximum load carrying capacity of such panels accurately. The so called Elastic Plastic Finite Element Alternating Method (Pyo et al. (1994)) was extended to account for the propagating c...

Numerical methods such as boundary element and finite element methods are widely used for the stress analysis in solid mechanics. This study presents boundary element method based on the displacement discontinuity formulation to solve general problems of interaction between hydraulic fracturing and discontinuities. The crack tip element and a higher order boundary displacement collocation techn...

We consider the use of initially rigid cohesive interface models in a two-dimensional dynamic finiteelement solution of a fracture process. Our focus is on convergence of finite-element solutions to a solution of the undiscretized medium as the mesh spacing x (and therefore time-step t) tends to zero. We propose the use of pinwheel meshes, which possess the ‘isoperimetric property’ that for any...