基于粘聚力模型的铝–碳化硅界面行为的跨尺度仿真

Molecular Dynamics Simulation of Al-SiC Interfacial Behavior Based Cohesive Zone Model

摘要: 为研究理想构件与缺陷构件拉伸与剪切过程界面原子变形机理和应力变化规律，建立了铝–碳化硅基体Ⅰ型和Ⅱ型断裂模式下的三维分子动力学模型。仿真结果表明拉伸过程中裂纹发生扩展后，应力到达峰值，并开始下降直至为零；剪切过程由于位错塞积和止裂，应力–位移曲线呈锯齿状波动下降。最后采用应力–位移曲线所得参数，建立了基于粘聚力模型的纳米颗粒增强铝基复合材料的有限元模型，拉伸应力–应变仿真结果与拉伸试验结果吻合较好。

Abstract: In order to investige the interfacial atom deformation chechanism and change rules of stress in tension and shear state, molecular dynamics models for Mode I and Model II failure were performed. The silulation results show that the stress reaches the maximum when the crack propagates and descends up to zero during tension process. During the shear process, the stress-displacement curves fluctuate to the minimal value due to the dislocation pileup and crack healing. According to the parameters abtained from stress-displacement curves, a tension finete element model based cohesive zone law for nanosized silicon carbide particles (SiCp) reinforced aluminium-based matrix composite materials has been established. The variaton trend of tension stress-strain is the same as experimental data.