The nite element method is now well established as a robust and reliable numerical technique in many areas of solid mechanics. There are however problems where the use of the nite element method is cumbersome like the modeling of moving discon-tinuities due to the need to update the mesh to match the geometry of the discontinuity. Even for stationary cracks, in three-dimensional solids, contsru...

The energy release rate (ERR) proposed by Irwin based on a theory by Griffith [1, 2] has been extensively used as a fracture criterion in 2D for brittle domains. Under in-plane mixed mode loading (modes I+II), the direction of crack initiation from cracks and sharp V-notches was determined by the orientation at which the ERR attains its maximum. Using the newly developed asymptotic expansion pr...

We present a numerical implementation of the Francfort-Marigo model of damage evolution in brittle materials. This quasi-static model is based, at each time step, on the minimization of a total energy which is the sum of an elastic energy and a Griffith-type dissipated energy. Such a minimization is carried over all geometric mixtures of the two, healthy and damaged, elastic phases, respecting ...

Results of “generation” (determination of dynamic stress-intensity factor variation with time, for a specified crack-propagation history) studies, as well as “prediction” (determination of crack-propagation history for specified dynamic fracture toughness vs crack-velocity relationships) studies of dynamic crack propagation in plane-stress/strain situations are presented and discussed in detail...

-In this paper, several formulations of moving-singularity finite element procedures for fast fracture analysis are evaluated as to their accuracy and efficiency. INTRODUCTION IN REFS. [1-3] the authors have presented a "moving singular-element" procedure for the dynamic analysis of fast crack-propagation in finite bodies. In this procedure, a singularelement, within which a large number of ana...

The objective of this paper is to present a procedure based on moving (or shifting) isoparametric elements for the analysis of dynamic crack propagation. The fracture parameters, such as the stress intensity factors or energy release rates for dynamically propagating cracks, are evaluated by far-field path-independent integrals that were recently derived by the authors. The combined use of the ...

Abstract: The thermo-elastic fracture problem and equations are established for aluminium alloy Metal Inert Gas (MIG) welding, which include a moving heat source and a thermoelasticity equation with the initial and boundary conditions for a plate structure with a crack. The extended finite element method (XFEM) is implemented to solve the thermo-elastic fracture problem of a plate structure wit...

We propose an approximation scheme for a variational theory of brittle fracture. In this scheme, the energy functional is approximated by a family of functionals depending on a small parameter and on two fields: the displacement field and an eigendeformation field that describes the fractures that occur in the body. Specifically, the eigendeformations allow the displacement field to develop jum...

Stress-corrosion of silica by water is studied by exploring the stress-dependent potential energy surface computed quantum mechanically at the level of molecular orbital theory. An ordered silica nanorod with clearly defined nominal tensile stress is constructed to model a structural unit of the stressed crack tip. Three competing hydrolysis reaction pathways are determined, each involving a di...