Theoretical Predictions of Lattice Parameters and Mechanical Properties of Pentaerythritol Tetranitrate under the Temperature and Pressure by Molecular Dynamics Simulations

Abstract

Molecular dynamics simulations with condensed-phase optimized molecular potentials for atomistic simulation studies force field are performed to investigate the structure, equation of state, and mechanical properties of high energetic material pentaerythritol tetranitrate. The equilibrium structural parameters, pressure-volume relationship and elastic constants at ambient conditions agree excellently with experiments. In addition, fitting the pressure-volume data to the Birch-Murnaghan or Murnaghan equation of state, the bulk modulus B0 and its first pressure derivative B 0 are obtained. Moreover, the elastic constants are calculated in the pressure range of 0-10 GPa at room temperature and in the temperature range of 200-400 K at the standard pressure, respectively. By the Voigt-Reuss-Hill approximation, the mechanical properties such as bulk modulus B, shear modulus G, and the Young modulus E are also obtained successfully. The predicted physical properties under temperature and pressure can provide powerful guidelines for the engineering application and further experimental investigations.

Dependence of the Elastic Stiffness Tensors of PETN, α‐RDX, γ‐RDX, ϵ‐RDX, ϵ‐CL‐20, DAAF, FOX‐7, and β‐HMX on Hydrostatic Compression

“…The dependence of the elastic stiffness tensor of PETN on hydrostatic pressure up to 10 GPa was evaluated using molecular dynamics simulations at 298 K with the COMPASS force field by Tan et al . [70]. Figure 27 shows that the predicted dependences of most of the components of the elastic stiffness tensor on hydrostatic pressure are roughly consistent between our DFT−D calculations (Table 9) and the room temperature molecular dynamics simulations.…”

“…The origin of the discrepancy between the elastic stiffness tensors reported in Ref. [70] and this work is not known.…”

Polymorphic Transition in Traditional Energetic Materials: Influencing Factors and Effects on Structure, Property, and Performance

“…We first turn our attention to the polymorphism of the six traditional ECs. TNT, as a benchmark of ECs, exists in two polymorphs under common conditions, m-TNT and o-TNT. , Four polymorphs of PETN, which is an important primary explosive, have been confirmed, including PETN-I under ambient condition, PETN-II at high temperature approaching decomposition, and PETN-III and PETN-IV under high pressure . Among all the observed polymorphs of RDX, the α form is the most stable form under common conditions, the β form is a heat-induced phase, and γ, ε, δ, ζ, and η forms exist under high pressure. − Eight phases have been reported for HMX, including the α, β, ε, γ, ϕ, ζ, η, and δ forms. − The α, β, and δ forms of HMX are all stable under common conditions.…”