Capozza Rosario, Barel Itay, Urbakh Michael
International School for Advanced Studies (SISSA), Trieste, Italy.
Sci Rep. 2013;3:1896. doi: 10.1038/srep01896.
Time-dependent increase of frictional strength, or frictional aging, is a widely observed phenomenon both at macro and nanoscales. The frictional aging at the nanoscale may result from nucleation of capillary bridges and strengthening of chemical bonding, and it imposes serious constraints and limitations on the performance and lifetime of micro- and nanomachines. Here, by analytical model and numerical simulations, we investigate the effect of inplane oscillations on friction in nanoscale contacts which exhibit aging. We demonstrate that adding a low amplitude oscillatory component to the pulling force, when applied at the right frequency, can significantly suppress aging processes and thereby reduce friction. The results obtained show that frictional measurements performed in this mode can provide significant information on the mechanism of frictional aging and stiffness of interfacial contacts.
摩擦强度随时间的增加，即摩擦老化，是在宏观和纳米尺度上广泛观察到的现象。纳米尺度的摩擦老化可能源于毛细桥的成核和化学键的强化，并且它对微纳机器的性能和寿命施加了严重的限制。在此，通过解析模型和数值模拟，我们研究了平面内振荡对呈现老化的纳米尺度接触中摩擦的影响。我们证明，在以正确频率施加时，向拉力添加低振幅振荡分量可显著抑制老化过程，从而降低摩擦。所得结果表明，以这种模式进行的摩擦测量可以提供有关摩擦老化机制和界面接触刚度的重要信息。
