scholarly journals Evaluation of operational properties of aviation oils by tribological parameters

2021 ◽  
Vol 99 (1) ◽  
pp. 43-50
Author(s):  
O. Mikosianchyk ◽  
◽  
O. Yakobchuk ◽  
R. Mnatsakanov ◽  
A. Khimko ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Hydrodynamic Lubrication ◽  
Practical Significance ◽  
Shear Stresses ◽  
Specific Work ◽  
Friction Contact ◽  
Near Surface ◽  
Antifriction Properties ◽  
Lubrication Mode ◽  
Contact Surfaces

The quality of aviation oils was evaluated online on the basis of their lubricating, antifriction, rheological and antiwear properties in the friction contact. The use of the software and hardware complex for evaluation of operational characteristics of triboelements is offered. Approbation of the proposed methodology was performed on aviation oils SM-9. The increase in antifriction properties of the “Bora B” SM-9 oil was established to be due to the formation of limiting adsorption layers of lubricant on friction-activated contact surfaces, which are characterized by low shear stresses of the lubricant, and their structuring provides high effective viscosity in the contact at a level of 5142 Pa.s. It was revealed that at start-up the lubricant temperature is 20 0С and the mixed lubrication mode prevails, but with increasing the lubricant temperature to 100 0С the elastic-hydrodynamic (contact-hydrodynamic) lubrication mode dominates, then at maximum rotation speed of friction pairs the hydrodynamic lubrication mode dominates, regardless of oil temperature, which indicates the effective separation of the contact surfaces due to the formation of a lubricating layer between them. Analysis of the specific work of friction in the friction contact showed that the instability of this parameter evidences to intensification of destructive processes in the near-surface layers of metal and reduction in its wear resistance. The decrease in wear resistance of the lagging surface in the conditions of rolling with sliding for all types of investigated oils is due to the different directions of the friction force vector in the contact. In the course of operation of friction pairs in nonstationary conditions, the softening of the surface metal layers occurs, which has a positive effect on the tribological processes in the contact. The practical significance of the work consists in developing a methodology of analysis of lubricants, which makes it possible to more accurately evaluate their performance and provide recommendations for the choice of lubricant for specific friction units.

scholarly journals Methods for increasing the wear resistance of heavy loaded metal-polymer tribosystems

2021 ◽  
Vol 2131 (5) ◽  
pp. 052035
Author(s):  
I Kolesnikov ◽  
E Novikov ◽  
V Kolesnikov ◽  
A Sychev
Keyword(s):  
Wear Resistance ◽  
Mechanical Engineering ◽  
Friction Contact ◽  
Friction Units ◽  
Contact Surfaces ◽  
The Creation ◽  
The Given ◽  
Vital Factor ◽  
Metal Polymer

Abstract Methods of increasing the wear resistance and reliability of friction units are generating considerable interest being a vital factor in transport, mechanical engineering, and other fields of technology. The solution of the given problem is impossible without the creation of self-regulating structures on the friction contact surfaces. We strongly believe that this problem can be solved by creating multicomponent functional layers (hereafter MFL) on tribocontact.

scholarly journals The Effect of the Slippage Degree at Rolling with Slipping on the Wear Resistance of Contact Surfaces

2016 ◽  
Vol 6 (2) ◽  
pp. 48 ◽  
Author(s):  
Tareq M.A Al-quraan ◽  
Oksana O. Mikosyanchik ◽  
Rudolph G. Mnatsakanov
Keyword(s):  
Wear Resistance ◽  
Slip Rate ◽  
Secondary Structures ◽  
Surface Layers ◽  
Near Surface ◽  
Active Elements ◽  
Deformed State ◽  
Contact Surfaces

<p class="1Body">The regularities of the wear of the steel 1045 during cutting off the feed of a lubricant under the non–stationary friction conditions were established. The influence of the properties of the secondary structures, formed on the contact surfaces under conditions of rolling with a different degree of slippage, on the wear of advancing and lagging surfaces was determined. The influence of specific friction work, the degree of hardening – weakening of surface layers of metal and the intensity of saturation by active elements of near–surface layers of metal on the wear resistance of friction pairs is examined. The change is established in localization of the depth of spreading the stressed and deformed state of material of the contact surfaces with an increase in the slip rate from 0.315 m/s to 1.14 m/s at rolling with the slippage.</p>

Assessment of sand stabilization potential of a plant-derived biomass

2016 ◽  
Vol 23 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Dunja Perić ◽  
Paul A. Bartley ◽  
Lawrence Davis ◽  
Ali Ulvi Uzer ◽  
Cahit Gürer
Keyword(s):  
Area Ratio ◽  
Cross Sectional Area ◽  
Experimental Program ◽  
Early Age ◽  
Shear Stresses ◽  
Sectional Area ◽  
Cross Sectional ◽  
Near Surface ◽  
Total Cross Sectional Area ◽  
Dry Sand

AbstractLignin is a coproduct of biofuel and paper industries, which exhibits binding qualities when mixed with water. Lignin is an ideal candidate for a sustainable stabilization of unpaved roads. To this end, an experimental program was devised and carried out to quantify effects of lignin on compaction and early age shear strength behaviors of sand. Samples were prepared by mixing a particular type of coproduct called calcium lignosulfonate (CaL) with sand and water. Based on the extensive analyses of six series of strength tests, it was found that a normalized cohesion increased with an increasing normalized areas ratio. Normalizations were carried out by dividing the cohesion and area ratio by gravimetric CaL content whereby the area ratio was obtained by dividing the portion of the cross-sectional area occupied with lignosulfonate-water (CaL-W) paste by the total cross-sectional area. While the increase in the normalized cohesion eventually leveled out, the cohesion peaked at 6% of CaL. Thus, sand-CaL-water (S-CaL-W) mixes sustained larger shear stresses than dry sand for a range of normal stresses below the limiting normal stress. Consequently, the early age behavior indicates that adding CaL-W to sand is clearly beneficial in the near-surface applications in dry sand.

Near Surface Research and Excitation Horizon Prediction Based on Old River Course of Xiaoqing River in Shan Dong

2013 ◽  
Vol 664 ◽  
pp. 94-98
Author(s):  
Guang De Zhang
Keyword(s):  
Seismic Data ◽  
Practical Significance ◽  
Cone Penetration ◽  
Surface Deposition ◽  
Near Surface ◽  
Sedimentary Characteristics ◽  
The Difference ◽  
Exploration Area ◽  
Data Requirements ◽  
Static Cone Penetration Test

Following deepened exploration and development in Shengli exploration area, seismic data requirements are also getting higher and higher. However, in recent years the difference of Xiaoqing river on both sides have made us know that the importance of this problem. In view of the above, this task is aimed at quaternary shallow of old river course within Xiaoqing River. Our analysis of lithology and sedimentary characteristics are using static cone penetration test and rock core exploration method, and we want to reappear near surface deposition of old river course within Xiaoqing River. The research is close combined with the exploration demand and theoretical study, so it has important theoretical and practical significance.

scholarly journals Epoxy antifriction wollastonite-filled materials

Vestnik MGSU ◽  
2019 ◽  
pp. 311-321
Author(s):  
Elena M. Gotlib ◽  
Аlmira R. Khasanova ◽  
Engel R. Galimov ◽  
Аlla G. Sokolova
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Adhesion Strength ◽  
Quaternary Ammonium ◽  
Epoxy Compound ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Antifriction Properties ◽  
The Impact ◽  
Compound Materials

Introduction. Domestic mineral natural-origin filler ‘wollastonite’, also known as calcium methyl silicate, is widely used as a base for wear-resisting epoxy antifriction materials. Due to anisodiametric shape of its particles, wollastonite functions as a micro reinforcement fibre enhancing adhesion strength and wear resistance of epoxy compositions, improving their antifriction properties, especially when organomodifying by quaternary ammonium salts. In this regard, the investigation of the impact of chemical composition of such surfactants as quaternary ammonium salts on the properties of epoxy compound materials presents utmost interest for researchers developing low-friction materials. Materials and methods. Epoxy diane resin ED-20 was hardened with aminoalkylphenol AF-2. Content of epoxy hardener was determined by equimolar ratio of epoxy groups to amine groups. Domestic wollastonite of the grade Miwoll 10-97 was used as filler, particle length to the diameter correlated as 15:1. The wollastonite surface was activated with surfactants belonging to domestically produced quaternary ammonium salts. Wear resistance of specimens was tested by means of the vertical optical caliper IZV-1. Friction coefficient was estimated with the assistance of the computer-automated frictional machine CSM Instruments Tribometer. Adhesion strength of glue joint was determined as per GOST 28840-90 standard. Two bars of sheet aluminium were used as glued surfaces as per GOST 14759-69 standard. Results. Reduction of wear of epoxy coatings when modified with micro reinforcing wollastonite can be explained by the increase of cross-linking degree of the polymer. The length of alkyl radical of quaternary ammonium salts used for wollastonite surface activation affects the intervals between the epoxy links. As the quaternary ammonium salt chain length is growing, wear of epoxy materials is reducing. Introduction of the wollastonite containing metallic oxides in the epoxy composites increases wear resistance and adhesion strength and reduces coating friction coefficients. Conclusions. Hardened with the AF-2 and filled with the wollastonite of the Miwoll 10-97 grade, the epoxy compound materials have enhanced wear resistance and adhesion strength and lower friction coefficient. The best result is observed when applying wollastonite modified with a surfactant belonging to the class of quaternary ammonium salts. The wollastonite can be used for practical purposes as a perspective reinforcing agent for epoxy materials with improved wear resistance, enhanced adhesion to metals and reduced friction coefficient.

A Surface Analytical Study of the Effects of Water and Oxygen on Tribological Behavior of DLC Films

2005 ◽  
Author(s):  
O. L. Eryilmaz ◽  
A. Erdemir ◽  
J. A. Johnson ◽  
N. Mehta ◽  
B. Prorok
Keyword(s):  
Surface Chemistry ◽  
Friction And Wear ◽  
Analytical Study ◽  
Tribological Behavior ◽  
Mechanistic Explanation ◽  
Sliding Contact ◽  
Diamond Like Carbon ◽  
Near Surface ◽  
X Ray ◽  
Contact Surfaces

In this study, we explored the effects of water and oxygen molecules on friction and wear of diamond-like carbon (DLC) films. Specifically, using Raman and x-ray photoelectron spectroscopies we attempted to analyze the near surface chemistry and microstructure of sliding contact surfaces and correlated these findings with changes in friction and wear of DLC films. Tribological tests were run in a ball-on-disk machine under 2 to 5 N loads and in dry and moist nitrogen and oxygen environments. Based on the tribological and surface analytical findings, a mechanistic explanation is provided for the high friction and wear of DLC in dry and humid oxygen environments.

Measurement of Residual Stresses within a PWR Swaged Heater Tube

2011 ◽  
Vol 70 ◽  
pp. 279-284 ◽  
Author(s):  
D.M. Goudar ◽  
Ed J. Kingston ◽  
Mike C. Smith ◽  
Sayeed Hossain
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Stress Measurement ◽  
Measurement Techniques ◽  
Residual Stress Distribution ◽  
Hole Drilling ◽  
Shear Stresses ◽  
Outer Diameter ◽  
Near Surface ◽  
Heater Tube

Frequent failures of the pressuriser heater tubes used in Pressurised Water Reactors (PWRs) have been found. Axial cracks initiating from the tube outer diameter have been detected in some tubes as well as the resulting electrical problems. Replacement of the heater tubes requires an undesirably prolonged plant shutdown. In order to better understand these failures a series of residual stress measurements were carried out to obtain the near surface and through-thickness residual stress profiles in a stainless steel pressuriser heater tube. Three different residual stress measurement techniques were employed namely, Deep-Hole Drilling (DHD), Incremental Centre Hole Drilling (ICHD) and Sachs’ Boring (SB) to measure the through thickness residual stress distribution in the heater tubes. Results showed that the hoop stresses measured using all three techniques were predominantly tensile at all locations, while the axial stresses were found to be tensile at the surface and both tensile and compressive as they reduce to small magnitudes within the tube. The magnitude of the in-plane shear stresses was small at all measurement depths at all locations. The various measurement methods were found to complement each other well. All the measurements revealed a characteristic profile for the through-thickness residual stress distribution.

The Influence of Elastic Deformation of the Roll and the Sheet in a Hydrodynamically Lubricated Cold Rolling Process

1995 ◽  
Vol 117 (3) ◽  
pp. 468-475 ◽  
Author(s):  
P. M. Lugt ◽  
W. E. ten Napel
Keyword(s):  
Cold Rolling ◽  
Film Thickness ◽  
Elastic Deformation ◽  
Hydrodynamic Lubrication ◽  
Rolling Process ◽  
Process Conditions ◽  
Shear Stresses ◽  
Strip Surface ◽  
Roll Flattening ◽  
Dense Grid

A model has been developed for simulating hydrodynamic lubrication in cold rolling. Both Roelands’ and Barus’ viscosity-pressure relations have been applied. Thermal effects regarding heat development caused by plastic deformation as well as work hardening have been included. Furthermore, elastic deformation of the surfaces has fully been incorporated in the model, i.e., elastic deformation of both the strip and the rolls. The governing equations have been solved numerically throughout the entire contact i.e. inlet, work and outlet zone using a very dense grid. Multigrid techniques have been used to solve the equations. It will be shown here that roll flattening has a significant effect on film thickness. However, elastic deformation of the strip material in the inlet region even has a more pronounced effect on film thickness and thus on several process conditions. Furthermore, it is shown that the choice of the viscosity-pressure parameter is limited. Higher values of this parameter cause excessive shear stresses on the strip surface.

Elasto-hydrodynamic lubrication of rolling-contact surfaces

Wear ◽  
1962 ◽  
Vol 5 (2) ◽  
pp. 168
Keyword(s):  
Hydrodynamic Lubrication ◽  
Rolling Contact ◽  
Contact Surfaces
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