腐蚀损伤处微裂纹成核的分子动力学模拟

Molecular dynamics simulation of micro-cracks nucleation at corrosion damage area

针对环境作用下结构表面微裂纹在腐蚀损伤处成核过程的复杂性和在结构寿命评估中的重要性,从微观角度出发,采用分子动力学方法并结合速度Verlet算法,通过求解原子间的作用力和速度,对广泛用于工程结构的单晶铝板,在外界载荷作用下腐蚀损伤处微裂纹成核过程进行模拟。结果表明:随着加载步的增加,模型中的原子先偏离理想晶格位置,随着加载继续进行,腐蚀坑底部原子键开始断裂,在45°的方向萌生出两条微裂纹。

Under service environment, micro- crack at structure surface in corrosion nucleation is complex, and plays an important role in the structure life assessment from microscopical viewpoint. Molecular dynamics simulation and speed Verlet algorithm were adopted to study the nucleation process of micro-cracks at corrosion damage and the process of crack propagation phenomena of single crystal aluminum plate via the solution of force and speed between atoms. The results show that with the loading steps increasing, atomic disorder phenomenon is strengthened and distorted, atomic bonds break and is accompanied by the micro-crack initiation in the direction of 45 degrees.