基于颗粒流离散元模型的弹丸侵彻细观混凝土数值模拟方法研究

摘要

利用颗粒离散单元法，研究弹丸侵彻细观混凝土模型中弹丸受到介质的阻应力与侵彻速度的关系。采用蒙特卡罗法随机生成并投放混凝土骨料且骨料的粒径分布满足级配曲线。通过对混凝土颗粒离散元细观力学模型进行单轴压缩实验、巴西劈裂实验和双轴压缩实验的参数反演，确定细观模型参数，能使细观混凝土模型具有和一般混凝土等效的力学性能。分析了骨料、过渡层和砂浆三相材料各细观参数对混凝土单轴压缩应力应变关系影响以及锥形弹和平头弹弹丸直径对侵彻阻应力的影响。将颗粒离散元细观力学模型方法计算的弹丸阻应力与空腔膨胀理论计算模型相比较，表明计算离散元方法具有良好的精度和实用性。%The relationship between penetration resistance and velocity of penetration in a projectile penetrating meso-scale concrete model was studied here using the particle flow discrete element method.Concrete aggregates whose size distribution satisfied a grading curve were randomly generated and put in using Monte Carlo method.In order to get the same effective mechanical properties as those of the macro-scale model,the parameters of the micro-scale model were determined by applying the parameter inversion technique in uniaxial compression, splitting tensile, and biaxial compression tests using the particle flow discrete element micromechanical model.The influences of the aggregate, transition layer and mortar 3-phase material microscopic parameters on concrete uniaxial compression stress-strain relation and the effects of diameter of projectiles with flat and conical nose on penetration resistance stress were analyzed.The comparison of the numerical results of resistance stress calculated with the particle flow discrete element micromechanical model and the analytical results based on the cavity expansion theory showed that the discrete element model has good applicability and accuracy.