Fractographic aspects of crack branching instability using a phase field model

摘要

A phase field model of a crack front propagating in a three dimensionalbrittle material is used to study the fractographic patterns induced by thebranching instability. The numerical results of this model give rise to cracksurfaces that are similar to those obtained in various experimental situations.Depending on applied loading configurations and initial conditions, we showthat the branching instability is either restricted to a portion of the crackfront or revealed through quasi two dimensional branches. For the former, thecrack front leaves on the main broken surface either aligned or disorderedparabolic marks. For the latter, fractography reveals the so called {\em\'echelons} cracks showing that branching instability can also induce crackfront fragmentation.