A kinetic model of fracture of simple liquids

The molecular-dynamic (MD) simulation is performed of the processes of generation and growth of cavities in stretched Lennard-Jones liquid. The process of homogeneous generation of cavities in a constant-volume cell is considered. The averaging of the lifetime of the homogeneous phase over the ensemble of MD trajectories is used to determine the nucleation rate as a function of pressure and temperature. The resultant correlation is compared with the classical theory of homogeneous nucleation. The initial stage of growth of spherical cavity is simulated, and the dependence of the rate of growth on pressure is determined along two isotherms. A kinetic model is suggested of fracture of liquid upon stretching at a constant rate. This model relates the volume of pores at an arbitrary instant of time to the kinetic characteristics of their generation and growth determined in MD models for single isolated cavities. The spallation strength of liquid, calculated using this kinetic model and MD data, only slightly depends on the rate of stretching. The calculation results agree well with the experimentally obtained dependence of spallation strength of hexane on the rate of stretching.