The importance of nonlinearities in material constitutive relations has long been appreciated in the continuum mechanics of macroscopic rods. Although the moment (torque) response to bending is almost universally linear for small deflection angles, many rod systems exhibit a high-curvature softening. The signature behavior of these rod systems is a kinking transition in which the bending is loc...

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...

A cohesive element formulation is proposed that provides a general framework to approximate experimentally measured Traction–Separation Law (TSL) shapes. Unlike other approaches, it does not assume specific TSL shapes, such as bi-linear or exponential. The shapes are defined generally, in piecewise-linear fashion, and Mode I shear (Mode II III) TSLs can have different Furthermore, added general...

A continuum damage mechanics (CDM) based constitutive model has been developed to describe elastic, plastic and damage behavior of porous rocks. The pressure sensitive inelastic deformation of porous rocks together with their damage mechanisms are studied for drained and undrained conditions. Fracture mechanics of microcrack andmicro-void nucleation and their coalescence are incorporated into t...

In dentistry, many preparation guidelines for allceramic crowns are still based upon clinical experience and those developed for metal ceramic crowns that may not be applicable and need further experimental and numerical evaluation. Some specific features are requiring investigation in dental prosthetic devices, for example, configurations of the crowns’ margin [1], marginal thickness [2, 3] an...

The problem of dynamic symmetric branching of a tensile crack propagating in a brittle material is studied within Linear Elastic Fracture Mechanics theory. The Griffith energy criterion and the principle of local symmetry provide necessary conditions for the onset of dynamic branching instability and for the subsequent paths of the branches. The theory predicts a critical velocity for branching...

We investigate the scaling properties of postmortem fracture surfaces in silica glass and glassy ceramics. In both cases, the 2D height-height correlation function is found to obey Family-Viseck scaling properties, but with two sets of critical exponents, in particular, a roughness exponent zeta approximately 0.75 in homogeneous glass and zeta approximately 0.4 in glassy ceramics. The ranges of...

We combine molecular dynamics simulations of deformation at the submicron scale with a simple continuum fracture mechanics model for the onset of crack propagation to calculate the macroscopic fracture energy of amorphous glassy polymers. Key ingredients in this multiscale approach are the elastic properties of polymer crazes and the stress at which craze fibrils fail through chain pullout or s...

The objective of this study was to evaluate the adequacy of current J-estimation models commonly used in probabilistic elastic±plastic analysis of ductile cracked structures. A newly developed probabilistic model based on elastic±plastic ®nite element method was used to evaluate the J-estimation model. In both models, the analyses involve elastic±plastic fracture mechanics for underlying determ...