New Type of Transmission Screw Nuts With Structure of Steel-Backing/Self-Lubrication Composite Lining

2012 ◽  
Author(s):  
Yousong Sun ◽  
Xianhui Zhou ◽  
Yongqi Cheng ◽  
Liangmo Wei ◽  
Chunmei Li
Keyword(s):  
Friction Coefficient ◽  
Carbon Fiber ◽  
Transmission Efficiency ◽  
The Other ◽  
Carbon Fabric ◽  
Low Friction ◽  
Metal Metal ◽  
New Type ◽  
Composite Lining ◽  
Carbon Fiber Epoxy

Transmission screw nuts with structure of steel-backing/self-lubrication composite lining have the advantages of high bearing capacity and low friction coefficient. Two materials and fabricating methods of linings were developed for the new screw nuts. Lubrication grooves on the female thread surfaces of the nuts were made during fabricating. One material was based on Carbon-Fabric/Epoxy (CFR/EP) and the lining was fabricated by pasting. The other was based on Carbon-Fiber/Epoxy (CF/EP) and the lining was fabricated by injecting. Experiments showed that in comparison with bronze nuts, the friction coefficients of CFR/EP and CF/EP nuts were reduced by 54% and 36% respectively, and the transmission efficiency increased by 50% and 29% respectively. The bearing capacities of the composite nuts were also increased. Differing from all metal-metal screws, the static frictions of the new screws were lower than the dynamic. It would have great effects on screw dynamic characteristics and need further researches.

Stochastic Theory of Human Slipping

2002 ◽  
Author(s):  
Ralph L. Barnett ◽  
Susanne A. Glowiak ◽  
Peter J. Poczynok
Keyword(s):  
Friction Coefficient ◽  
Duty Cycle ◽  
Stochastic Theory ◽  
The Other ◽  
Extreme Value Statistics ◽  
Conventional Theory ◽  
Low Friction ◽  
Friction Coefficients ◽  
Duty Cycles ◽  
New Concepts

The conventional approach to human slipping is essentially deterministic; it states that no slipping will occur when the average friction coefficient is greater than some critical friction criterion. Under this condition, pedestrians will not slip when they encounter the average friction coefficient. On the other hand, to successfully negotiate a walk of n-steps they must not slip when they encounter the smallest of the n friction coefficients. Consequently, a new slip theory has been formulated as a problem in extreme value statistics. An elegant relationship is obtained among the probability of slipping, the critical friction criterion, the number of steps taken by the walker, and the central measure, scatter, and asymmetry of the distribution of friction coefficients. The new theory reveals the structure of human slipping in a startling way that introduces completely new concepts: the go/no go nature of classical slip predictions is replaced by a probability of slipping; low friction floor/footwear couples may lead to fewer slips than high friction ones; slipping can occur in any case where conventional theory predicts “no slip”; and the number of slips depends on the distance traveled by a pedestrian. Finally, this paper develops the idea that the slipperiness of a real floor must be evaluated for a duty-cycle. Duty-cycles can be represented as frequency histograms when a floor is homogeneous and isotropic.

scholarly journals The Influence of Ice-Resistant Coatings Characteristics to the Energy Efficiency of Ice-Going Ships

2021 ◽  
Vol 320 ◽  
pp. 01007
Author(s):  
V.A. Veselov ◽  
M.V. Kitaev ◽  
P.O. Pastukhov ◽  
O.E. Surov
Keyword(s):  
Energy Efficiency ◽  
Friction Coefficient ◽  
Power Plant ◽  
Service Life ◽  
Frictional Resistance ◽  
Experimental Tests ◽  
Operating Conditions ◽  
The Other ◽  
Low Friction ◽  
Ice Navigation

The main purpose of ice-resistant coatings designed for icebreakers and ice navigation ships is the ability to protect of the ship’s hull in the most severe operating conditions. The special coatings certified by the Classification Societies for ice abrasion can provide this protection. These coatings allow to reduce the required thickness of the ship’s hull and reduce the construction weight of the ships. On the other hand, these coatings must have a low friction coefficient, which reduce the frictional resistance of the hull on ice and fuel consumption, increase the service life of the ship and power plant, reduce CO2 emissions into the atmosphere and affect to the operational and economic efficiency of the ship. In this paper, we present the results of experimental tests of friction coefficient on ice for various types of ice-resistant coatings and analysis the influence of ice-resistant coatings characteristics to the energy efficiency of ice-going ships.

Comparison on the Tribological Properties of Roller and Guide Tribo-Pair Used in Antenna Deployable Structure

2021 ◽  
Vol 1041 ◽  
pp. 37-44
Author(s):  
Tao Feng ◽  
Tao Li ◽  
Yu Zhang ◽  
Zhuo He ◽  
Lin Wang
Keyword(s):  
High Temperature ◽  
Friction Coefficient ◽  
Carbon Fiber ◽  
Epoxy Resin ◽  
Tribological Properties ◽  
Resin Composites ◽  
Gcr15 Steel ◽  
Deployable Structure ◽  
Epoxy Resin Composites ◽  
Carbon Fiber Epoxy

The tribological properties of roller and guide tribo-pair are important for the design of deployable structure for space-borne perimeter truss antenna. In this study, carbon fiber epoxy resin composites are used as the guide material; while polyimide and GCr15 steel are used as the roller material. Then, friction coefficient of polyimide ball and GCr15 steel ball against carbon fiber epoxy resin composites disk were compared and investigated on the high-temperature, ball-on-disk tribometer under different operating conditions, respectively. The wear morphology of disk was measured by laser scanning confocal microscope. The results show that the friction coefficient of the polyimide ball against carbon fiber epoxy resin composites tribo-pair has better tribological properties. Meanwhile, the friction coefficients of this pair are mainly depend on abrasive wear under low pressure and velocity conditions while the adhesive wear has dominated influence on the friction coefficient for high pressure and velocity conditions. Besides, the tribological properties of carbon fiber epoxy resin composites are mainly affected by ploughing of surface roughness at low temperature, while by surface debonding at high temperature.

Research on the Tribological Properties of SF Polymer Water-Lubricated Bearings

2010 ◽  
Vol 150-151 ◽  
pp. 102-107 ◽  
Author(s):  
Zhu Xin Wu ◽  
Lin Liu Zheng ◽  
Fa Xiao Fan
Keyword(s):  
Friction Coefficient ◽  
Tribological Properties ◽  
Load Capacity ◽  
Low Friction ◽  
Swelling Properties ◽  
Shipbuilding Industry ◽  
Simulation Testing ◽  
New Type ◽  
Water Swelling ◽  
High Load Capacity

In the paper, the SF polymer water lubricated bearings is taken as the research objects. Both material testing and bearing simulation testing are carried out to research the tribological properties of bearings including water swelling properties, friction coefficient, and wear-resistant properties mainly. The results show that the SF material, which is a new type of material used in water lubricated tail bearing, has the characteristics of low friction coefficient, high load capacity, good wear-resistance, excellent self-lubricating properties, and low water swelling, which has a broad application in the shipbuilding industry.

Experimental investigation on tribological properties of carbon fabric composites: effects of carbon nanotubes and nano-silica

2017 ◽  
Vol 233 (5) ◽  
pp. 874-884 ◽  
Author(s):  
Majid R Ayatollahi ◽  
R Moghimi Monfared ◽  
R Barbaz Isfahani
Keyword(s):  
Carbon Nanotubes ◽  
Friction Coefficient ◽  
Friction And Wear ◽  
Nano Particles ◽  
Woven Composites ◽  
Carbon Fabric ◽  
Wear Properties ◽  
Low Friction ◽  
Fabric Composites ◽  
Friction And Wear Properties

In this study, the effects of nano-[Formula: see text] and carbon nanotubes on the friction and wear properties of carbon-epoxy woven composites have been explored. The unfilled carbon fabric composites and carbon fabric composites filled with carbon nanotubes and nano-[Formula: see text] were fabricated by vacuum infusion process. The worn surfaces were examined and possible wear mechanisms of unfilled and filled carbon fabric composites were discussed. In addition, the friction coefficient curves of unfilled and filled carbon fabric composites were analyzed and compared. The experimental results showed that either of the two nano-particles improved the friction coefficient and wear rate of carbon fabric composites; however, better improvement was observed for nano-SiO2. By adding these nano-particles to unfilled carbon fabric composites, a primary steady-state period with a low friction coefficient appeared in the friction coefficient curve of the composites, which indicates enhancement in bonding strength between carbon fiber and epoxy matrix due to the interfacial reinforcing action of the nano-particles.

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