【摘要】 研究了振动载荷作用下金属涂层中纳米微痕对其阻尼影响机理,采用LAMMPS分子动力学模拟软件对理想结构金属涂层和含纳米微痕涂层进行模拟计算,求得振动作用下各模型的应力-应变关系曲线及含纳米微痕涂层模型的总能量、微观结构变化。通过两个模型的应力-应变关系曲线对比分析了不同结构模型的阻尼性能,并通过能量和微观结构变化,进一步探讨了纳米微痕对涂层阻尼影响的机理。结果表明:纳米微痕周围的位错、空位及弯结对的变化增强了涂层的阻尼性能,并且纳米微痕未发生扩展破坏。更多还原

【Abstract】 The damping behavior of the ideal metal coatings,with and without well-defined nano-cracks,under vibration loading was physically modeled,numerically simulated with molecular dynamics simulation code( LAMMPS),and experimentally evaluated with scanning electron microscopy and conventional dynamic mechanical thermal analyzer. The influence of the nano-cracks on the mechanical properties,including the damping,stress-strain correlation,total energy,and defects reconstruction of the copper coatings under forced vibration,was investigated.The simulated results show that the nano-cracks have a major impact on the stress-strain correlation and damping behavior of the Cu-coatings. To be specific,the vibration-energized reconstruction,evolution,growth,removal,and inner friction,etc. of the localized defects,including the nano-crack,dislocations,vacancies,interstitials and bending twinning,all negatively affect the elastic energy storage,resulting in a deviation of stress-strain correlation accompanied by some enhancement of vibration damping. No destructive extension of nano/micro-cracks could possibly occur.更多还原