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-dimensional brittle material is used to study thenfractographic patterns induced by the branching instability. The numerical results of this model give rise to cracknsurfaces that are similar to those obtained in various experimental situations. Depending on applied loadingnconfigurations and initial conditions, we show that the branching instability is either restricted to a portion ofnthe crack front or revealed through quasi-two-dimensional branches. For the former, the crack front leaves onnthe main broken surface either aligned or disordered parabolic marks. For the latter, fractography reveals the soncalled ´echelon cracks showing that branching instability can also induce crack front fragmentation.