Fatigue crack growth behavior has been examined in a particulate titanium diboride (TiB2)–reinforced iron-based composite that had been produced via a mechanical alloying process. Comparison with equivalent unreinforced material indicated that fatigue crack growth resistance in the composite was superior to monolithic matrix material in the near-threshold regime. The composite exhibited relativ...

Abstract-A plate with a pre-existent through crack is considered under the action of a remote bending moment and a remote in-plane force. The problem statement is reduced to the solution of two coupled integral equations with strongly singular kernels. The independent variables in the latter equations are the closure displacement and rotation angle. The corresponding closure force and moment di...

Progressive radial cracking of a clamped plate subjected to crack-face closure is studied. The material behavior is assumed to be elastic-brittle. The cracks are assumed to be relatively long in the sense that the three-dimensional contact problem can be described via a statically equivalent two-dimensional idealization. The number of cracks is supposed large enough to permit a quasi-continuum ...

A plasticity-induced crack-closure model was used to study fatigue crack growth and closure in thin 2024-T3 aluminum alloy under constant-R and constant-Kmax threshold testing procedures. Two methods of calculating crack-opening stresses were compared. One method was based on contact-K analyses and the other on contact crack-openingdisplacement (COD) analyses. These methods gave nearly identica...

In this paper, two different techniques for mixed-mode type engineering fracture analysis, by using the weight-function method, are presented. These two methods are (a) the virtual crack extension technique (VCE), and (b) the equivalent domain integral method (EDI). For mixed-mode weight-function evaluation, a technique of using two reference load states, both of which cannot be either pure mod...

With advanced composites increasing replacing traditional metallic materials, the material inhomogeneity and inherent anisotropy of such materials lead to not only new attributes for aerospace structures, but also introduce new technology to damage tolerant design and analysis. The deleterious effects of changes in material properties and initiation and growth of structural damage must be addre...

In previous studies, enamel showed indications to occlude small cracks in-vivo and exhibited R-curve behaviors for bigger cracks ex-vivo. This study quantifies the crack tip's toughness (K(I0),K(III0)), the crack's closure stress and the cohesive zone size at the crack tip of enamel and investigates the toughening mechanisms near the crack tip down to the length scale of a single enamel crystal...