一种高颗粒体积分数PBX细观模型的生成方法

A Method of Generating Mesoscopic Models for PBXs with High Particle Volume Fraction

为了从细观尺度上对高聚物黏结炸药(PBX)的力学性能进行模拟,将蒙特卡洛方法中级配的概念引入高体积分数的PBX细观模型,与Voronoi方法相结合,形成了一种可以考虑级配分布的Voronoi多边形颗粒生成方法,通过颗粒修正、收缩、切角和平滑等处理,建立了考虑级配和体积分数达94%及以上的PBX细观结构模型,模型在边界处还可保持周期连续性。采用数值流形(NMM)方法对不同颗粒级配条件下的三组PBX细观模型进行了单轴压缩模拟。将NMM模拟所得等效弹性模量与文献实验结果进行了比较。分析了模拟结果与实验结果之间出现偏差的原因,讨论了PBX细观结构模型生成方法的合理性。结果表明,PBX的等效弹性模量随体积分数的提高而增大,并且体积分数越高,增速越快;同时,当体积分数低于30%及高于85%时,颗粒的级配对等效模量的影响较小,而当30%≤体积分数≤85%时,颗粒级配对等效模量影响显著。

To simulate the mechanical properties of polymer bonded explosives(PBXs)from the meso-scale,the concept of gradation of Monte Carlo method was introduced into the PBX model of high volume fraction.A generating method of Voronoi polygon particles which can consider the distribution of graded particles was formed by combining the Voronoi polygon particle gen-eration algorithm.A PBX meso structure model considering gradation and volume fraction of 94%and above was established through the treatment of particle modification,shrinking,corner cutting and smoothing etc.At the same time,the model can maintain periodic continuity at the boundary.The uniaxial compression simulation for PBX meso model of three groups under different gradation condition was performed by numerical manifold method(NMM).The equivalent elastic modulus obtained from NMM simulation was compared with the experimental results in literature.The reasons of deviation occurred between the simulation results and the experimental ones were analyzed,and the rationality of the PBX meso structure model generation method was discussed.Results show that the equivalent modulus of PBX increases with the increase of volume fraction,and the higher the volume fraction is,the faster the growth rate is.At the same time,when the volume fraction is below 30%and higher than 85%,the effect of the particle gradation on the equivalent modulus is smaller,but when 30%≤volume fraction≤85%,the effect of the particle gradation on the equivalent modulus is significant.