Lubrication of saliva layer on oral and throat mucosa and its friction reduction effect

2020 ◽  
Vol 2020 (0) ◽  
pp. OS10-04
Author(s):  
Kenji SHIMOKASA ◽  
Hiromichi OBARA ◽  
Hiroshi MIZUNUMA
Keyword(s):  
Friction Reduction ◽  
Reduction Effect

scholarly journals Vibration-induced nanoscale friction modulation on piezoelectric materials

Friction ◽  
2022 ◽  
Author(s):  
Jiawei Cao ◽  
Qunyang Li
Keyword(s):  
Piezoelectric Materials ◽  
Effective Means ◽  
Mechanical Vibration ◽  
Friction Model ◽  
Friction Reduction ◽  
Small Scale ◽  
Vibrational Amplitude ◽  
Vibration Source ◽  
Reduction Effect ◽  
Piezoelectric Thin Film

AbstractMechanical vibration, as an alternative of application of solid/liquid lubricants, has been an effective means to modulate friction at the macroscale. Recently, atomic force microscopy (AFM) experiments and model simulations also suggest a similar vibration-induced friction reduction effect for nanoscale contact interfaces, although an additional external vibration source is typically needed to excite the system. Here, by introducing a piezoelectric thin film along the contact interface, we demonstrate that friction measured by a conductive AFM probe can be significantly reduced (more than 70%) when an alternating current (AC) voltage is applied. Such real-time friction modulation is achieved owing to the localized nanoscale vibration originating from the intrinsic inverse piezoelectric effect, and is applicable for various material combinations. Assisted by analysis with the Prandtl—Tomlinson (P—T) friction model, our experimental results suggest that there exists an approximately linear correlation between the vibrational amplitude and the relative factor for perturbation of sliding energy corrugation. This work offers a viable strategy for realizing active friction modulation for small-scale interfaces without the need of additional vibration source or global excitation that may adversely impact device functionalities.

scholarly journals Effect of Compressive Prestrain on the Anti-Pressure and Anti-Wear Performance of Monolayer MoS2: A Molecular Dynamics Study

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 275 ◽  
Author(s):  
Ning Kong ◽  
Boyu Wei ◽  
Yuan Zhuang ◽  
Jie Zhang ◽  
Hongbo Li ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Friction Reduction ◽  
Dynamics Simulation ◽  
Monolayer Mos2 ◽  
Lubrication Mechanism ◽  
Load Bearing Capacity ◽  
Deformation Degree ◽  
Wear Performance ◽  
Out Of Plane ◽  
Reduction Effect

The effects of in-plane prestrain on the anti-pressure and anti-wear performance of monolayer MoS2 have been investigated by molecular dynamics simulation. The results show that monolayer MoS2 observably improves the load bearing capacity of Pt substrate. The friction reduction effect depends on the deformation degree of monolayer MoS2. The anti-pressure performance of monolayer MoS2 and Pt substrate is enhanced by around 55.02% when compressive prestrain increases by 4.03% and the anti-wear performance is notably improved as well. The improved capacities for resisting the in-plane tensile and out-of-plane compressive deformation are responsible for the outstanding lubrication mechanism of monolayer MoS2. This study provides guidelines for optimizing the anti-pressure and anti-wear performance of MoS2 and other two-dimension materials which are subjected to the in-plane prestrain.

Friction Reduction Effect of Soft Coatings

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Zhou Chen
Keyword(s):  
Friction Coefficient ◽  
Normal Load ◽  
Static Friction ◽  
Hard Coatings ◽  
Friction Reduction ◽  
Element Analysis ◽  
Tangential Load ◽  
Static Friction Coefficient ◽  
Tangential Stiffness ◽  
Reduction Effect

Finite element analysis is conducted on an elastic-plastic full stick contact between a rigid flat and a deformable coated sphere with a soft coating. A combined normal and tangential load is applied to the rigid flat, and the sliding inception is assumed as a result of the decreasing tangential stiffness of the contact junction. As the coating becomes thicker, the static friction coefficient first decreases reaching a minimum and then increases. This demonstrates a friction reduction effect of soft coatings that is opposite to hard coatings. The static friction coefficient decreases with increasing normal load as the contact junction contains more plasticity and becomes more compliant.

Experimental Study on the Through-Mask Electrochemical Micromachining (EMM) Process

2011 ◽  
Vol 189-193 ◽  
pp. 692-696 ◽  
Author(s):  
Quan Dai Wang ◽  
Ji Ming Xiao ◽  
Yan Li
Keyword(s):  
Large Scale ◽  
Surface Texturing ◽  
Friction Reduction ◽  
Electrochemical Micromachining ◽  
Textured Surface ◽  
Reduction Effect ◽  
Interacting Surfaces ◽  
Etched Surface ◽  
Optimized Conditions ◽  
Friction Drag Reduction

Surface texturing is a widely accepted approach for friction reduction in mechanical components. Through-mask electrochemical micromachining (EMM) is a simple and reliable process for mass manufacturing of microstructure array on metal surface. However, to obtain engineered surface texture with a prescribed shape, size, orientation, and distribution to investigate how forms and shapes of surface texturing affect the tribological properties on interacting surfaces, the machining conditions still need to be optimized. In this work, the electroetching conditions involving the formulation of the electrolyte, voltage, current density, machining gap and agitation method are optimized. With the optimized conditions, the ordered microstructures with a feature size down to 5m and smooth etched surface in large-scale are obtained and the preliminary friction drag reduction effect of the textured surface is demonstrated.

Improving frictional performance of ring-liner system under cylinder deactivation conditions by surface texturing

2021 ◽  
pp. 146808742110146
Author(s):  
Yongfang Zhang ◽  
Cheng Liu ◽  
Yanjun Lu ◽  
Jianxiong Kang ◽  
Hongbo Luo ◽  
...  
Keyword(s):  
Surface Texture ◽  
Gasoline Engine ◽  
Surface Texturing ◽  
Friction Reduction ◽  
Cylinder Deactivation ◽  
Liner System ◽  
Frictional Performance ◽  
Reduction Effect ◽  
Effect Of Surface ◽  
Total Average

In this study, a method of surface texture is considered to improve the frictional performance of the ring-liner system (i.e. RLS) under the conditions of cylinder deactivation (i.e. CDA). To assess the effectiveness of the method, a lubrication model is developed with considerations of the liner deformation, the actual rheological properties of lubricant, and the lubricant transport. By solving the model numerically, the friction reduction effect of surface texture for the RLS under the CDA is investigated. The results show that the surface texture can improve the friction properties significantly. For a six-cylinder gasoline engine, 7.57% and 7.28% decreases in the total average friction loss and power loss are observed when the RLS under the CDA is surface textured.

Influence of Acoustic Pressure and Flexural Vibration on Friction Reduction Effect by Ultrasonic

2011 ◽  
Author(s):  
Takahiro Nakayama ◽  
Mitsuaki Ochi ◽  
Kenji Kofu
Keyword(s):  
Friction Coefficient ◽  
Pressure Distribution ◽  
Acoustic Pressure ◽  
Particle Density ◽  
Flexural Vibration ◽  
Friction Reduction ◽  
Lower Plate ◽  
Reduction Effect ◽  
The Relationship

The influence of acoustic pressure and flexural vibration on friction reduction effect by ultrasonic has been investigated in this study. Then the relationship between friction reduction of particles by each effect and the particle density has been shown by using of ultrasonic. Additionally, the maximum of particle density which could receive the friction reduction effect by the acoustic pressure has been expressed. In short, when the particle density was large, the influence of friction reduction effect by the acoustic pressure decreased and the influence of friction reduction effect by the flexural vibration grew. In this study, two plates were set parallel to each other. The dried particles were scattered on the lower plate, and the ultrasonic was applied. Then, the entire equipment setup was tilted slowly until the scattered particles began to move, and the friction coefficient was measured. Then, influence of acoustic pressure and flexural vibration were evaluated. In order to evaluate the reduction effect by acoustic pressure and flexural vibration, firstly, the distribution of acoustic pressure between reflection plate and the vibration plate have been measured. As a result, it was clarified that acoustic pressure distribution became the almost same whether ultrasonic was applied for the upper or lower plate, and the reflection plate vibrated little. Therefore it was possible to divide the influence of acoustic pressure and flexural vibration on the friction reduction.

CFD Analysis of Friction-Reduction Effect of Micro-Textured Surfaces in Lubricant

2018 ◽  
Vol 12 (2) ◽  
pp. 206-214 ◽  
Author(s):  
Yue Sun ◽  
Shaolin Xu ◽  
Tomoki Kyoizumi ◽  
Keita Shimada ◽  
Masayoshi Mizutani ◽  
...  
Keyword(s):  
Stokes Equations ◽  
Lubricant Film ◽  
Friction Reduction ◽  
Navier Stokes ◽  
Orthogonal Experimental Design ◽  
Textured Surfaces ◽  
Navier Stokes Equations ◽  
Geometrical Features ◽  
Reduction Effect ◽  
Friction Surfaces

This paper investigates the effects of geometrical features of tailored textures on friction reduction of a surface with a lubricant-film thickness of several to several-tenths micrometers, using the Navier-Stokes equations and the orthogonal experimental design. The results indicate that the surface textured with the selected sawtooth riblets in lubricant can have up to 93.83% less friction than an untextured surface. The thickness of the lubricant film plays the most important role in friction reduction; the height and the ridge angle of the riblets are the secondary factors. The results and principles obtained can potentially be used in the designing of low-friction surfaces in precision machines with transmission parts.

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