【摘要】 采用经典的分子动力学方法,分析了两端固支的纳米梁的力学行为特征.在初始应变下,梁的表面原子发生了重构,而初始应变能仅是重构能的1%,随着分子动力学迭代的开始,初始应变能逐渐转化为梁中原子的热运动动能和梁的谐振能量.从其能量的变化曲线得到,梁的谐振频率为2.32×1010Hz.与连续介质近似结果对比发现,该谐振频率对应的杨氏模量为101GPa,小于体硅的131GPa,说明在该尺度下杨氏模量小于体材料.另外,分子动力学结果显示,发热是纳米梁耗散机制的重要方式,即谐振能量转化为梁中原子的热运动动能.更多还原

【Abstract】 The double-clamped nano-beam was simulated with the classic molecular dynamic (MD) method, especially on the mechanic behavior. Under the initial strain, the surface atoms in the beam reconfigured, and this was the surface energy. The potential energy of the initial strain was only 1% of it. In the process of MD steps, the initial strain energy gradually converted to the harmonic vibration energy of the beam and the thermal kinetic energy of the atoms. The harmonic vibration energy also converted to thermal energy. The harmonic frequency of the beam was 2.32×10~ 10 Hz by MD. This result agreed with the continuum approximation, when the Young’s modulus was 101GPa, less than the 131 GPa for bulk silicon.更多还原