Spatiotemporal behavior of void collapse in shocked solids

Area of Science:

• Materials Science
• Computational Physics
• Chemical Dynamics

Background:

• Hot spot generation is crucial for understanding shock-induced chemical reactions in materials.
• The role of voids in modifying shock wave propagation and energy localization is not fully understood.

Purpose of the Study:

• To investigate hot spot generation in a 3D defective Lennard-Jones solid with a void using molecular dynamics simulations.
• To analyze the impact of void size and collapse dynamics on shock-enhanced chemistry.

Main Methods:

• Performing molecular dynamics (MD) simulations on a defective Lennard-Jones solid model.
• Monitoring temperature and the number of energetically colliding particles (shock-enhanced chemistry indicator).
• Analyzing particle velocities and temperatures within voids during collapse.

Main Results:

• The normalized number of energetically colliding particles saturates for nanoscale voids and peaks post-collapse.
• Temperature enhancement requires larger voids and peaks during early collapse stages.
• Ejected molecules within voids exhibit enhanced average velocity and temperature due to momentum and energy focusing.

Conclusions:

• Void collapse significantly influences hot spot generation and shock-enhanced chemistry.
• Nanoscale voids play a critical role in intensifying localized energy deposition.
• The focusing of momentum and energy within voids leads to enhanced molecular kinetic energy.