以RDX为基的浇注PBX力学性能与本构模型

Mechanical Properties and Constitutive Models of RDX Based Cast PBX

为研究一种黑索今（RDX）基浇注高聚物粘结炸药（PBX）的力学性能与本构模型,利用INSTRON材料试验机及改进分离式Hopkinson压杆（SHPB）进行了准静态和动态单轴压缩实验,获得了材料在10^-4~10^-2s^-1及843~1490 s^-1应变率范围内的应力-应变曲线。结果表明：该浇注PBX的变形过程分为线性段、强化段和软化段。准静态加载下该浇注PBX具有明显的应变率效应,其弹性模量、压缩强度、临界应变与相对对数应变率之间近似呈线性关系;而在实验应变率范围内,动态加载下特别是加载初期应变率效应不明显,同时发现其破坏准则由应力控制,材料在12MPa附近发生破坏。借鉴推进剂及橡胶材料本构关系的研究结果,分别提出了能描述浇注PBX一维动、静态压缩力学行为的率相关本构模型,该模型与实验结果误差小于10%吻合较好。

Stress-strain curves of a R DX Based cast PBX w ere obtained using an IN ST R O N testing machine and an optimized Split Hopkinson pressure bar（ SHPB） at different strain rates（ 10^-4~ 10^-2/ s and 8432~ 14904/ s）. R esults show that mechanical properties of the material including elastic modulus,compressive strength,and strain at-maximum-stress,increase linearly w ith strain rate in quasi-static tests. W ith in small dynamic strain rate range,w eak rate dependence is observed in SHPB tests,especially at the initial loading stage. T he dynamic failure criterion w ere controlled by stress,and materials failure occurrs at 12M Pa. Based on rate-dependent phenomenological material models of solid propellants and rubber materials,one-dimension constitutive equations for quasi-static and dynamic compression are presented,show ing a good agreement w ith experimental data w ith error less than 10%.