Brittle/quasi-brittle transition in dynamic fracture: An energetic signature

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 3-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 microcracks. A simple model allows to relate both the energetic and fractographic measurements. These results suggest that dynamic fracture at low velocities in amorphous materials is controlled by the brittle/quasi-brittle transition studied here.

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

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

Julien Scheibert, Claudia Guerra, Fabrice Célarié, Davy Dalmas, Daniel Bonamy. Brittle/quasi-brittle transition in dynamic fracture: An energetic signature. Physical Review Letters, 2010, 104 (4), pp.045501. ⟨10.1103/PhysRevLett.104.045501⟩. ⟨hal-00394618v3⟩