Phonon emission induced dynamic fracture phenomena

Area of Science:

• Solid-state physics
• Materials science
• Computational materials science

Background:

• Crack propagation in brittle materials is a fundamental process in materials science.
• Understanding energy dissipation mechanisms is crucial for predicting material failure.
• Previous models often overlook the role of emitted phonon energy.

Purpose of the Study:

• To quantify the phonon energy emitted during rapid crack propagation in brittle crystals.
• To investigate the influence of this phonon energy on crack behavior at various length scales.
• To propose an enhancement to existing models of dynamic crack propagation.

Main Methods:

• Molecular dynamics simulations were employed to model crack propagation.
• Calculations focused on the energy emitted as phonons.
• Simulations analyzed crack behavior across atomic, micrometer, and macro scales.

Main Results:

• Phonon energy emission varies with crack plane and propagation direction.
• This energy dictates preferred crack systems and deflection at the atomic scale.
• It causes reduced maximum crack speeds at the micrometer scale and limits theoretical speeds at the macroscale.

Conclusions:

• Phonon energy emission is a critical factor in rapid crack propagation.
• This energy influences crack dynamics from atomic to macroscopic levels.
• Incorporating phonon energy into the Freund equation is proposed for improved accuracy.