CHARACTERIZING HIGH-SPEED IMPACT BEHAVIOR OF UHMWPE THROUGH MOLECULAR DYNAMICS SIMULATION

In this paper, a study on the ballistic impact behavior of the ultra-high-molecular-weight-polyethylene (UHWMPE) microstructure through molecular dynamics simulations is presented. Unlike most of the existing works, of which the focus has been on the ballistic impact resistance of amorphous polyethylene, our research studied mechanical properties of both crystal and amorphous structure of the fibril which together constitute the shish-kebab structure of the UHMWPE macro-fibril. In the numerical model, a spherical diamond block that represents a rigid projectile is used to impact a polyethylene block. Two different types of potential energy functions are compared to investigate the energy dissipation mechanisms in tensile simulation. The first type of potential energy function is the polymer consistent force field (PCFF) based on CFF91 (consistent force field) with additional parameters specified for polymer materials. The second type of potential function used is the AIREBO (Adaptive Intermolecular Reactive Empirical Bond Order) potential. The presented MD simulations were conducted by the open-source MD code Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS).