| Polymer bonded explosive(PBX)are commonly used in penetration warhead because of its excellent detonation performance and safety performance.This paper is devoted to the building of a model for cast PBX explosive charge filled in projectile during penetrating concrete target.According to different penetration,damage-coupled viscoelastic model and viscoelastic-plastic model have been developed to describe mechanical responds of cast PBX explosive under different temperature in broad strain rate.Two constitutive models are used in explosive charge filled in projectile during penetrating concrete target.The main content can be summarized as follows:1)Polymer-bonded explosives demonstrate so strong strain rate that most constitutive models of PBXs are classified into quasi-static and dynamic at present.in this paper,a viscoelastic constitutive model based on actual damage mechanisms has been established to describe both the quasi-static response and dynamic response of PBXs,which accounts for complex phenomenology including temperature,strain rate,and creep effects.2)In order to investigate the mechanical response and damage response of cast PBX explosive charge under different loading conditions.Three types of damage modes including intragranular voids,crystal fractures and interfacial debonding are considering in the constitutive model.Quasi-static uniaxial compression and tensile tests and split-Hopkinson pressure bar test have been modeling and simulation to study mechanical responses and damage evolutions.Intragranular voids damage in compression evolutes faster than it in tensile.Debonding damage is the predominant failure mode in quasi-static tension and tensile creep while the crystal fractures are mainly occur with the strain rate increase.3)Viscoelastic model based on actual damage mechanisms for explosive charge filled in projectile during penetrating concrete target is established.Calculation results show that:in the process of penetration of single target,when the head of projectile go through the target,tail of charging impact the shell because of inertial effect,which leads to crystal fractures even ignition.The intragranular voids collapse is related to the volume strain and is mainly distributed in the head and tail of the charging.The debonding damage is mainly distributed on the outside wall of the charging.4)In multi-layer target penetration process,the PBX charge is subjected to cyclic loading and unloading while the viscoelastic model cannot describe the residual strain and strain hardening in cyclic loading accurately.A viscoelastic-plastic model is used for PBXs charge filled in projectile during penetrating multi-layer concrete target.The results show that when the projectile penetrates the second target,it sustains more overloaded than the others.The projectile velocity during penetrating the third target plate is small,and there was a large residual strain in the charge.Therefore,the tail of the charge cannot impact the shell of the projectile.By analyzing the strain,temperature and pressure distribution and the variations of plastic work,viscous dissipation,volume compression work and internal energy,The highest temperature rise area of the charge appears in the outer wall of the charge. |
