准静态拉伸下PBX力学性能的三维细观模拟

Three-dimensional Mesoscale Simulation of PBX Mechanical Properties under Quasi-static Tension

为了研究PBX在准静态拉伸下的力学响应行为,探索细观结构对力学性能的影响规律及机制,采用有限元计算方法,结合双线性内聚力模型,基于自编程序构建的PBX三维细观模型,研究了在单轴拉伸条件下颗粒体积分数、颗粒尺寸以及界面性能3个细观参数对PBX力学性能的影响。结果表明,三维模拟获得的宏观力学性能与实验数据能够较好吻合。此外,还发现颗粒体积分数增加会导致杨氏模量显著增加,同时也会导致抗拉强度升高,颗粒体积分数从61.2%增加至95.6%使得抗拉强度升高了38.9%,增加颗粒尺寸则会导致抗拉强度降低,颗粒尺寸从120μm增加到160μm,使其抗拉强度降低了13%;界面性能对抗拉强度的影响最为显著,当界面强度从0.5MPa升至5MPa时,抗拉强度从2.58MPa升至6.82MPa,说明相比于颗粒体积分数及尺寸,改善界面性能是提升PBX抗拉强度更为有效的方法。

To study the mechanical response behavior of PBX under quasi-static tension and explore the laws and mechanisms of the influence of mesostructure on mechanical properties,the effects of three mesoscale parameters,namely particle volume fraction,particle size,and interface properties,on the mechanical properties of PBX under uniaxial tensile conditions were investigated by a finite element calculation combined with the bilinear cohesive zone model and 3D mesoscale models of PBX constructed by the self-written program.The results show that the macroscale mechanical properties obtained by 3D simulation agree well with the experimental data.Additionally,the increase in particle volume fraction causes a noticeable increase in Young’s modulus,which can also increase the tensile strength;the increase in particle volume fraction from 61.2%to 95.6%causes an increase of 38.9%in tensile strength,whereas an increase in the particle size leads to a decrease in tensile strength;the increase in particle size from 120μm to 160μm causes a decrease in tensile strength of 13%.When the interface strength increases from 0.5MPa to 5MPa,the tensile strength increases from 2.58MPa to 6.82MPa,suggesting that altering the interface properties is a more effective method of enhancing the tensile strength of PBX than modifying particle volume fraction and size.