基于改进Hashin-Shtrikman方法预测PBX有效弹性模量

高聚物黏结炸药(PBX)是一种颗粒高度填充的含能复合材料,其单质炸药晶体的体积百分含量通常达到了80%以上,采用经典的细观力学模型Hashin-Shtrikman界限法获得的PBX有效弹性模量与实验测试值存在较大误差.引入含有炸药密度参数的"界面结合修正系数",得到了一个改进的Hashin-Shtrikman模型.设计了三种密度的以TATB为基的PBX,测定了相应的弹性模量值,并确定了模型的修正系数为0.813(ρ/ρ_0)~(8.64)和0.296(ρ/ρ_0)~(8.68).分别利用经典的和改进的Hashin-Shtrikman模型计算了该型PBX的有效体积模量和有效剪切模量,同时与实验值进行了对比.结果表明:以TATB为基的PBX其有效弹性模量随密度的减小呈指数形式衰减,且体积模量与剪切模量随密度的影响程度几乎一致,其指数约为8.6;改进的Hashin-Shtrikman模型的预测结果与实验值的误差在1%左右;改进后的模型合理,拟合精度高,适合于对双组分PBX有效弹性模量的预测.

On Predicting Effective Elastic Modulus of PBX by Modified Hashin-Shtrikman Model

Polymer bonded explosives are composites containing elastic energetic particles in a viscoelastic binder.The volume fraction of the elastic particles in PBX is normally greater than 80%,therefore using the classical analytical meso-mechanics model(Hashin-Shtrikman)to estimate the effective elastic modulus of TATB-based PBX is quite inaccurate.A new term named "interface bonding parameter" which contains the density of the bulk PBXs was promoted and a modified model of Hashin-Shtrikman was obtained.The samples with different densities were prepared,and their elastic modulus was measured,and the modified coefficients of the model were obtained to be 0.813(ρ/ρ_0)~(8.64)or 0.296(ρ/ρ_(0))~(8.65).The elastic modulus was calculated by the classical HashinShtrikman model and by the modified model respectively.It shows that the modified model with "interface bonding parameter" can give more accurate results compared to that with the classical Hashin-Shtrikman model.The effective elastic modulus decays exponential with the decreasing of TATB-based PBX density,and the effective bulk modulus and the effective shear modulus are influenced by density to the same degree,and the exponents are about 8.6.The predicting and the experimental results are only 1% apart.It proves that the modified Hashin-Shtrikman can be used to predict the effective modulus of double-composition PBXs.