Stiff and soft active control of friction by vibrations and their energy efficiency
Stiff and soft active control of friction by vibrations and their energy efficiency
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DOI：
10.1007/s10010-018-0281-1
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发表时间：
2018-12-01
影响因子：
1.1
通讯作者：
Popov, V. L.
中科院分区：
文献类型：
--
作者：
Benad, J.;Popov, M.;Popov, V. L.
本论文建立在最近两项关于正向和横向振荡对摩擦的影响的理论研究的结果之上。研究结果被部分重写为更紧凑和无量纲的形式，以便以一致的方式并排呈现两种振荡模式的结果。由此表明，对于所考虑的系统，宏观摩擦系数仅是无量纲滑动速度和无量纲振荡幅度的函数。此外，通过将包括叠加振荡的滑动运动所需的总能量与没有附加振荡的相同滑动运动所需的能量进行比较，首次表征了两种模式的能量效率。结果表明，该比率也只是二维无量纲系统参数的函数。我们考虑位移控制设置中的简单单弹簧模型。任何系统动力学反馈都被忽略。弹簧的下端在刚性平面上滑动、粘住或跳跃。在正常振动的情况下，只有当接触点进行粘滑运动（“摩擦的刚性控制”）时，宏观摩擦系数才能减小，而在侧向振动的情况下，当接触点连续滑动时，宏观摩擦系数也可以减小（“摩擦的软控制”）。研究发现，对于任何系统参数组合，具有叠加横向振荡的运动比没有振荡的相应运动需要更多的能量。然而，对于正常振荡的情况，存在系统参数的组合，其中具有叠加振荡的运动比没有振荡的参考情况需要更少、相同或更多的能量。
The present paper builds upon the results of two recent theoretical studies on the influence of friction by normal and sideways oscillations. The findings are in part rewritten to a more compact and dimensionless form so as to present the results for both oscillation modes side by side in a consistent manner. Thereby, it is shown that for the considered system the macroscopic coefficient of friction is only a function of a dimensionless sliding velocity and a dimensionless oscillation amplitude. Furthermore, the energy efficiency is characterized for both modes for the first time by comparing the total energy needed for a sliding motion which includes the superimposed oscillations with the energy needed for the same sliding motion without the additional oscillations. It is shown that this ratio is also only a function of the two dimensionless system parameters. We consider a simple one-spring model in a displacement-controlled setting. Any system-dynamical feedback is neglected. The lower end of the spring either slides, sticks or jumps on a rigid plane. In the case of normal oscillations, the macroscopic coefficient of friction can be reduced only when the contact point undergoes a stick-slip motion ("stiff control of friction") whereas with sideways oscillations the macroscopic coefficient of friction can be reduced also when the contact point is continuously sliding ("soft control of friction"). It is found that the motion with superimposed sideways oscillations requires more energy for any combination of system parameters, than the corresponding motion without the oscillations. For the case of normal oscillations however, there are combinations of system parameters for which the motion with the superimposed oscillations requires less, the same, or more energy than for the reference case without the oscillations.