A new continuum model to describe damage, fragmentation and large deformation of pulverized brittle materials is presented. The multiple-plane-microcracking (MPM) model, developed by Espinosa, has been modiAed to track microcracking on 13 orientations under high pressure, high strain rate and high deformation. This model provides the elastic and inelastic response of the material before massive...

We describe a non-destructive and inexpensive way of measuring the interface toughness between polymeric layers in microfabricated devices. A flat surface is bonded under pressure to a surface patterned with microscopic steps. When the pressure is removed, cracks develop at the interface as the material peels away from the steps. The toughness of the bond can be inferred from the crack lengths....

A new class of systems of strongly singular integrodifferential equations is examined, which emerges in the study of the bridged interface crack growth, e.g., in fiber stitched layered composites. This work generalizes the asymptotic analysis of strongly singular integral equations by Willis and Nemat-Nasser [Quart. Appl. Math., 48 (1990), pp. 741–753]. Singular perturbation solutions up to the...

The present paper deals with a micromechanical model of interface able to couple the damage (micro-crack) evolution, the non-penetration conditions (Signorini equations) and the friction effect (Coulomb’s law). At a typical point of the interface, a Representative Volume Element (RVE) is considered; it is characterized by the presence of two different materials and by a microcrack evolving alon...

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...

The excellent mechanical properties of carbon nanotubes (CNTS) are driving research into the creation of new strong, tough nanocomposite systems. Here, the first evidence of toughening mechanisms operating in carbon-nanotube-reinforced ceramic composites is presented. A highly ordered array of parallel multiwall CNTs in an alumina matrix was fabricated. Nanoindentation introduced controlled cra...