A Friction-Reducing Shaft Surface for Use With Standard Radial Sharp Lip Oil Seals

1981 ◽  
Author(s):  
James D. Symons
Keyword(s):  
Friction Reducing ◽  
Shaft Surface

Study of the character and causes of destruction of the cardan shaft of the propeller engine

2019 ◽  
Vol 85 (12) ◽  
pp. 43-50
Author(s):  
D. A. Movenko ◽  
L. V. Morozova ◽  
S. V. Shurtakov
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Yield Point ◽  
Protective Coating ◽  
Fracture Pattern ◽  
Corrosion Cracking ◽  
Tempered Martensite ◽  
Neck Formation ◽  
Static Mechanism ◽  
Shaft Surface

The results of studying operational destruction of a high-loaded cardan shaft of the propeller engine made of steel 38KhN3MFA are presented to elucidate the cause of damage and develop a set of recommendations and measures aimed at elimination of adverse factors. Methods of scanning electron and optical microscopy, as well as X-ray spectral microanalysis are used to determine the mechanical properties, chemical composition, microstructure, and fracture pattern of cardan shaft fragments. It is shown that the mechanical properties and chemical composition of the material correspond to the requirements of the regulatory documentation, defects of metallurgical origin both in the shaft metal and in the fractures are absent. The microstructure of the studied shaft fragments is tempered martensite. Fractographic analysis revealed that the destruction of cardan shaft occurred by a static mechanism. The fracture surface is coated with corrosion products. The revealed cracks developed by the mechanism of corrosion cracking due to violation of the protective coating on the shaft. The results of the study showed that the destruction of the cardan shaft of a propeller engine made of steel 38Kh3MFA occurred due to formation and development of spiral cracks by the mechanism of stress corrosion cracking under loads below the yield point of steel. The reason for «neck» formation upon destruction of the shaft fragment is attributed to the yield point of steel attained during operation. Regular preventive inspections are recommended to assess the safety of the protective coating on the shaft surface to exclude formation and development of corrosion cracks.

scholarly journals Tribological performance of various metal-doped carbon dots as water-based lubricant additives and their potential application as additives of poly(ethylene glycol)

Friction ◽  
2021 ◽  
Author(s):  
Weiwei Tang ◽  
Xuejun Zhu ◽  
Yufeng Li
Keyword(s):  
Ethylene Glycol ◽  
Tribological Properties ◽  
Carbon Dots ◽  
Lubricant Additives ◽  
Poly Ethylene Glycol ◽  
Wear Properties ◽  
Water Based ◽  
Friction Reducing ◽  
Poly Ethylene ◽  
Metal Doped

AbstractAdvances in nano-lubricant additives are vital to the pursuit of energy efficiency and sustainable development. Carbon dots (CDs) have been widely investigated in the domain of lubricant additives owing to their extraordinary tribological properties, in particular, their friction-reducing and anti-wear properties. Metal-doped CDs are a new type of CDs, and their friction-reducing and anti-wear properties are attracting increasing attention. Therefore, a series of CDs doped with various divalent metal ions have been successfully synthesized via one-pot pyrolysis. The tribological properties of the synthesized CDs as water-based lubricant additives are in the following order: Zn-CDs > Cu-CDs ≫ Mg-CDs > Fe-CDs > U-CDs. Specifically, adding 1.0 wt% of Zn-CDs into water-based lubricant results in 62.5% friction and 81.8% wear reduction. Meanwhile, the load-carrying capacity of the water-based lubricant increases from 120 N to at least 500 N. Zn-CDs as an additive have long service life. Additionally, anion-tuned Zn-CDs fabricated via anion exchange exhibit promise as lubricant additives for poly(ethylene glycol). Based on the results of wear scar surface analyses, it is discovered that tribochemical films, primarily composed of iron oxides, nitrides, metal carbonates, zinc oxides, zinc carbonates, organic compounds, and embedded carbon cores, formed on the rubbing surfaces with a thickness of approximately 270 nm when Zn-CDs are used as additives. This film combined with the “ball-bearing” and third-particle effects of Zn-CDs contributed to excellent lubrication performance.

Optimized Design of Vibration Controllers for Steady and Transient Excitation of Flexible Rotors

1995 ◽  
Vol 209 (3) ◽  
pp. 155-168 ◽  
Author(s):  
P S Keogh ◽  
C Mu ◽  
C R Burrows
Keyword(s):  
Measurement Error ◽  
Controller Design ◽  
Optimized Design ◽  
Rotor Vibration ◽  
Transient Vibration ◽  
Flexible Rotors ◽  
Vibration Attenuation ◽  
Measured Displacement ◽  
Control Forces ◽  
Shaft Surface

Controller designs for the attenuation of rotor vibration are investigated. Disturbance inputs leading to vibration are classified and related to control forces and defined control states. Optimization based on the H∞ norm is then used to minimize the influence of forcing disturbances, modelling error and measurement error. The practicalities of applying the method to an experimental rotor-bearing system, with hardware constraints on controller order, are stated. The controller was implemented experimentally to conduct steady state and mass loss tests. Steady synchronous, non-synchronous and transient vibration attenuation was demonstrated. It was also shown that measurement error, caused by shaft surface roughness, can be incorporated into the controller design without the need to remove the roughness component from the measured displacement signals. If the roughness influence is not included in the design and the uncontrolled vibration is small, unnecessary control forces may result, causing an increase in vibration.

scholarly journals Brush seal with thermo-regulating bimetal elements

2018 ◽  
Vol 8 (1) ◽  
pp. 307-313 ◽  
Author(s):  
Michał Stanclik
Keyword(s):  
Heat Flux ◽  
Contact Area ◽  
Heat Load ◽  
Experimental Results ◽  
Frictional Heat ◽  
Brush Seal ◽  
Thermoregulatory Function ◽  
Shaft Surface

Abstract This paper presents a new brush seal construction idea. It was shown that it is possible to use bimetallic elements for the construction of the brush seal, which have a thermoregulatory function by relieving a contact area between bristles and a shaft surface reducing frictional heat flux. This should improve the durability of the seal by diminishing the heat load and significantly decreases the temperature of the seal during the startup/ shutdown. This article shows a simplified construction of the concept brush seal as well as numerical and experimental results.

scholarly journals An Investigation on Tribological Properties and Lubrication Mechanism of Graphite Nanoparticles as Vegetable Based Oil Additive

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yu Su ◽  
Le Gong ◽  
Dandan Chen
Keyword(s):  
Friction Coefficient ◽  
Tribological Properties ◽  
Volume Fraction ◽  
Wear Volume ◽  
Lubrication Mechanism ◽  
Step Method ◽  
Antiwear Properties ◽  
Physical Deposition ◽  
Graphite Nanoparticles ◽  
Friction Reducing

This paper used graphite nanoparticles with the diameter of 35 and 80 nm and LB2000 vegetable based oil to prepare graphite oil-based nanofluids with different volume fractions by two-step method. The tribological properties of graphite nanoparticles as LB2000 vegetable based oil additive were investigated with a pin-on-disk friction and wear tester. Field emission scanning electron microscope (FE-SEM) and energy dispersive spectroscopy (EDS) were used to examine the morphology and the content of some typical elements of wear scar, respectively. Further, the lubrication mechanism of graphite nanoparticles was explored. It was found that graphite nanoparticles as vegetable based oil additive could remarkably improve friction-reducing and antiwear properties of pure oil. With the increase of volume fraction of graphite nanoparticles, the friction coefficient and the wear volume of disk decreased. At the same volume fraction, the smaller particles, the lower friction coefficient and wear volume. The main reason for the improvement in friction-reducing and antiwear properties of vegetable based oil using graphite nanoparticles was that graphite nanoparticles could form a physical deposition film on the friction surfaces.

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