Material Point Method Simulation of the Equation of State of Polymer-Bonded Explosive under Impact Loading at Mesoscale

Siyu Ge,Jian Sang,Shuai Yuan,Wenying Zhang,Glenn V Lo,Yusheng Dou

doi:10.3390/pr8080983

Abstract

Mesoscale simulation using the material point method (MPM) was conducted to study the pressure–volume (PV) variations of Octahydro-1,3,5,7-Tetranitro-1,2,3,5-Tetrazocine (HMX)/Estane polymer-bonded explosive (PBX) under impact loading. The PV isotherms and Hugoniot data were calculated for the different porosities and binder volume fractions. The PV isotherms were used to determine the parameters for the Birch– Murnaghan equation of state (EOS) for the PBX. From the EOS, the isothermal bulk modulus (K0) and its pressure derivative (K′0) were calculated. Additionally, the pseudo particle velocity and pseudo shock velocity variations were used to obtain the bulk wave speed c and dimensionless coefficient s for the Mie–Grüneisen EOS. The simulations provide an alternative approach for determining an EOS that is consistent with experimental observations.

Highlights

Polymer-bonded explosive (PBX), a polymer-matrix granular composite, is mainly composed of viscoelastic polymers and elastoplastic explosives particles
The results of this study show that the effective equation of state (EOS) derived from mesoscale simulations satisfies the above three criteria based on thermodynamic relations
2020, 8, 983 of this study show that the effective EOS derived from mesoscale simulations satisfies the above three criteria based on thermodynamic relations

Summary

Introduction

Polymer-bonded explosive (PBX), a polymer-matrix granular composite, is mainly composed of viscoelastic polymers and elastoplastic explosives particles. The huge difference between the properties of polymers and explosives makes it difficult to determine the thermodynamic and mechanical properties of the granular composite. An equation of state (EOS) is an equation that summarizes the relationship between several state functions (such as pressure P, volume V, temperature T, and internal energy E) of a system. An EOS can provide valuable microscopic insight into the bulk properties of energetic composite materials. Two types of EOS, reacted and unreacted, have been developed for energetic materials and have been the subject of extensive studies in the field. The commonly used model for reacted explosives is the Jones–Wilkins–Lee (JWL) EOS; for unreacted explosives, the

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Conclusion