Influence of Ultrasonic In-Plane Oscillations on Static and Sliding Friction and Intrinsic Length Scale of Dry Friction Processes

The force of friction between plates of different materials (steel, brass, copper, titanium, glass, aluminum, rubber, and Teflon, among others) and a steel sample oscillating in the sliding plane at a frequency of 40–70 kHz has been studied. The measured friction coefficient as a function of sliding velocity and velocity oscillation amplitude fits well with theoretical predictions based on the simple Coulomb friction law at sliding velocities larger than the actuation velocity. However, the friction coefficient tends to a finite value at small sliding velocities, which is contrary to the theoretical prediction. The static limit has been studied in detail. A strong decrease in the static friction force takes place at oscillation amplitudes of 20–60 nm. Such amplitudes are enough to control the friction coefficient. The experimental data for both static and sliding friction are interpreted within the framework of a microscopic model and a phenomenological macroscopic model. The notion of intrinsic friction slip length is introduced.     

旋转滑动摩擦副摩擦噪声影响因素实验研究

为探究滑动摩擦噪声的影响因素,采用单因素实验法分析了表面粗糙度、相对速度、载荷、摩擦副材料、润滑油中石墨烯质量分数对滑动摩擦噪声的影响。实验发现:实验所测摩擦噪声可大体分为前期、中期、稳定期;表面粗糙度越小,摩擦噪声越小;转速升高时,摩擦噪声逐渐增大,但随着转速的增大,摩擦降噪增幅有所下降;适当增大载荷有助于降噪;石墨烯的降噪效果优异;陶瓷摩擦副比轴承钢摩擦副更具降噪优势。     

润滑油对滑动摩擦副咬死性能的影响

在ＭＨＫ－５００型环块磨损试验机上对Ｎ４６＃机械油在不同供同温度下由４５＃淬火试环、试块组成的滑动摩擦副进行了抗咬死性能试验研究。试验结果表明：供油温度对摩擦副的抗咬死性能有较大的影响，在一定的范围内提高润滑油的供油温度有利于提高摩擦副的抗咬死能力。试验还发现：随着润滑油中磨粒的增多，摩擦副咬死极限载荷逐渐下降，且摩擦副失效后表面温度表现出不确定性。润滑同中磨粒状况对摩擦副咬死影响不可忽视。对摩擦     

超声波流量计换能器的人射角及振荡频率对测量精度的影响

文中以时差法为例,分析了超声波换能器中超声射线入射角及振荡频率对测量精度的影响,给出了换能器的选择原则。     

超声波流量计换能器的入射角及振荡频率对测量精度的影响

文中以时差法为例,分析了超声波换能器中超声射线入射角及振荡频率对测量精度的影响,给出了换能器的选择原则。     

石墨—金属摩擦副的静摩擦系数

对三种石墨材料与金属Ｃｕ１７Ｎｉ２配对摩擦副的静摩擦系数进行了测试。,测定了不同温度,载荷,润滑方式下的静摩擦系数。试验发现：温度对静摩擦系数的影响较小;油润滑条件下的静摩擦系数最小。     

滑动轴承摩擦因数的实验研究

结合西南交通大学自主研发的ZHS20滑动轴承试验台,通过实验展开对滑动轴承摩擦因数f的研究,测定f-λ曲线和p-f-n曲线,探讨摩擦因数f和特性参数λ的关系,并且与福格波尔(Vogelphol)关于摩擦因数f的研究成果进行比较分析;进一步研究了不同压强p下和不同转速n耦合时,对f曲线的影响,对研究多参数影响下轴承摩擦因数的变化规律具有实际指导意义。     

超声波驱动的摩擦特性研究

采用自制的模拟超声马达定子齿椭圆振动的超声驱动模拟试验装置，研究了接触预压紧力和两相超声波振动的激励电压峰峰值之比对超声驱动的摩擦特性的影响。结果表明：在超声波振动驱动条件下，每一种摩擦材料都存在最佳的预压紧力和激励电压的组合。     

Influence of Load and Sliding Speed on Super-Low Friction of Nitinol 60 Alloy under Castor Oil Lubrication

In the present paper, the influence of load and sliding speed on super-low friction of Nitinol 60 alloy was investigated experimentally using Nitinol 60 alloy pin sliding over GCr15 steel disk under castor oil lubrication. Super-low coefficient of friction (COF) of Nitinol 60 alloy was achieved at the stable state, corresponding to so-called superlubricity regime in the presence of castor oil. The experimental results indicate that sliding speed employed in the friction tests plays great roles in the lubrication behaviors of Nitinol 60 alloy. When the friction tests are executed from low sliding speed to high sliding speed, COF decreases at the initial stage and on the contrary, COF increases at the stable stage. However, with the increase in load, COF firstly increases and then decreases at the initial stage. COF is unstable but still super low and remains almost the same value at the stable stage. These phenomena are explained and discussed in viewpoint of the characteristics of castor oil during the friction tests. It is found that the influence of sliding speed on the lubrication behaviors of Nitinol 60 alloy under castor oil lubrication is more obvious than that of load due to the characteristics structure of castor oil, therefore maintaining appropriate level of sliding speed to achieve super-low friction of Nitinol 60 alloy.