A new critical velocity in the dynamic fracture of brittle amorphous materials

Julien Scheibert (1, 2) , Claudia Guerra (1, 3) , Fabrice Célarié (1, 2) , Davy Dalmas (2) , Daniel Bonamy (1)

1 SPCSI - Service de Physique et de Chimie des Surfaces et Interfaces
2 SVI - Surface du Verre et Interfaces
3 Facultad de Ingeniería Mecánica y Eléctrica

Dynamic fracture experiments were performed in PMMA over a wide range of velocities and reveal that the fracture energy exhibits an abrupt 4-folds increase from its value at crack initiation at a well-defined critical velocity, below the one associated to the onset of micro-branching instability. This transition is associated with the appearance of conics patterns on fracture surfaces that, in many materials, are the signature of damage spreading through the nucleation and growth of micro-cracks. These results suggest a nominally brittle to quasi-brittle transition in the dynamic fracture of amorphous materials the implications of which are discussed.

Mots clés: dynamic fracture; amorphous materials; brittle; fracture energy; PMMA; fracture surface; roughness

Domaines: Mécanique des solides [physics.class-ph]; Science des matériaux [cond-mat.mtrl-sci]

Julien Scheibert, Claudia Guerra, Fabrice Célarié, Davy Dalmas, Daniel Bonamy. A new critical velocity in the dynamic fracture of brittle amorphous materials. 2009. ⟨hal-00394618v1⟩