Atomistic simulations are performed to study the statistical mechanical properties of gold nanoparticles. It is demonstrated that the yielding behavior of gold nanoparticles is governed by the dislocation nucleation around surface steps. Since the nucleation of dislocation is an activated process with the aid of thermal fluctuation, the yield stress at a specific temperature should vary statistically rather than being a definite constant value. Molecular dynamics simulations reveal that the yield stress follows a Gaussian distribution at a specific temperature. As the temperature increases, the mean value of yield stress decreases while the width of distribution becomes larger. Based on the numerical analysis, the dependence of mean yield stress on temperature can be well described by a parabolic function. This study illuminates the statistical features of the yielding behavior of nanostructured elements.

进行原子模拟以研究金纳米粒子的统计力学性能。结果表明，金纳米颗粒的屈服行为受表面台阶周围位错成核的支配。由于位错的形核是借助于热波动而激活的过程，因此在特定温度下的屈服应力应统计地变化，而不是确定的恒定值。分子动力学模拟表明，屈服应力在特定温度下遵循高斯分布。随着温度升高，屈服应力的平均值减小，而分布宽度变大。基于数值分析，可以通过抛物线函数很好地描述平均屈服应力对温度的依赖性。