基于细观颗粒夹杂模型的复合固体推进剂松弛模量预测

Estimation of relaxation modulus of composite solid propellant based on particle packing model

为更准确地预测不同固体颗粒体积分数的复合固体推进剂的松弛模量,采用了分子动力学方法对不同体积分数的复合固体推进剂细观模型进行建模.根据有限元理论及细观力学均匀化方法,计算在定应变工况下复合固体推进剂细观模型的平均应力随时间的变化,从而有效地预测复合固体推进剂的松弛模量.该方法有效地体现了随填充颗粒体积分数的增大,复合固体推进剂瞬时模量逐渐增大的变化规律及颗粒随机分布对复合固体推进剂瞬时模量的影响.将其应用到复合固体推进剂的设计过程中,可有效降低设计成本,缩短设计周期.

To estimate more accurately the relaxation modulus of composite solid propel lant with different particles volume fraction, the molecular dynamics method was adopted to construct solid propellant mesoscale models with different particle volume fraction. The mean stress of composite solid propellant mesoscale model varying with relaxation time was computed by finite element theory and mesomechanics homogenization method when the model was under a fixed strain load. So the effective relaxation modulus of composite solid propellant can be estimated. It can be seen clearly that the instantaneous modulus of compos ite solid propellant increases when particle volume fraction becomes larger and the influence of particles random distribution to the instantaneous modulus of composite solid propellant by the proposed method. When this method is applied to the design process of composite solid propellant, it can reduce the design cost and shorten the design cycle effectively.