Molecular dynamics research on effect of doping defects on properties of PETN

To investigate the effect of doping defects on properties of pentaerythritol tetranitrate (PETN), the "perfect" and doping defective crystal models of PETN containing pentaerythritol (PE), pentaerythritol mononitrate (PEMonoN), pentaerythritol dinitrate (PEDiN), and pentaerythritol trinitrate (PETRIN) were established, respectively. Molecular dynamics (MD) method was applied to perform simulations, and sensitivity, detonation performance, and mechanical properties were calculated and compared. The results indicate that compared with PETN (1 1 0) supercell model, the interaction energy of trigger bond and cohesive energy density of the doped defect models decreased by 2.21~12.43 kJ mol^-1 and 0.0219~0.0421 kJ cm^-3, respectively, indicating that the sensitivity of defective models increases and the safety decreases. The density, detonation velocity, and detonation pressure of the doped defect model decreased by 0.018~0.061 g cm^-3, 77.833~272.809 m s^-1, and 0.746~2.544 GPa, respectively, and the oxygen balance is declined, indicating that the energy density of PETN decreased and the power decreased. Doped defects also cause the elastic modulus, bulk modulus, and shear modulus of PETN to decrease by 0.75~2.16 GPa, 0.44~0.89 GPa, and 0.30~0.89 GPa, respectively. The ratio of bulk modulus to shear modulus and Cauchy pressure increased by 0.05~0.28 GPa and 0.09~1.13 GPa, respectively, indicating that the deformation resistance, fracture strength, and hardness of the doped defect model decrease, stiffness decreases, and flexibility and ductility increase.