Crack initiation and propagation in brittle crystals at the low energy regime
Dov Sherman (Technion)
From Atomistics to Reality: Spanning Scales in Simulations and Experiments Symposium A
Tue 10:45 - 12:15
CIT 165
Continuum 2D elastodynamics based Freund equation of motion suggests crack initiation at Griffith barrier and propagation speed obeying 0 < V < CR. Atomistic computer calculations, on the other hand, have been suggesting effects which are not in accord with the continuum approach; lattice trapping is the most significant. The fine details of the way cracks initiate and propagate in brittle crystals are still not well understood. These include the micro scale bond breaking mechanisms sequence, the meso scale plane-stress plane-strain transition and the exact shape of the propagating crack front, and the macroscopic energy-speed relationship at the low energy regime, which is considered forbidden. Our cleavage fracture experiments of silicon crystal show crack propagation at low speed with energy-speed relationship that apparently obeys Freund equation of motion. These findings, in addition to the fine details of the crack front, have yielded a new type of atomistic computer calculations that were able to ascertain the experimental results.