Boundary Lubrication in Transient Elliptical Contact: Part 1—Theoretical Formulation and Results

2019 ◽  
Vol 20 (4) ◽  
pp. 609-617 ◽  
Author(s):  
Di-Chu Xu ◽  
Qi Zhang ◽  
Jiu-Gen Wang
Keyword(s):  
Boundary Lubrication ◽  
Theoretical Formulation ◽  
Elliptical Contact ◽  
Contact Part

Elastic Contact and Friction Between Sliders and Circumferentially Textured Disks—Part II: Meniscus Force

1998 ◽  
Vol 120 (1) ◽  
pp. 35-41 ◽  
Author(s):  
K. Tanaka
Keyword(s):  
Frictional Coefficient ◽  
Critical Factor ◽  
Liquid Bridges ◽  
Height Distribution ◽  
Asperity Height ◽  
Lubricant Thickness ◽  
Theoretical Formulation ◽  
Meniscus Force ◽  
Elliptical Contact ◽  
The Mean

This series of three papers presents an experimental and numerical analysis of friction in a thin-film rigid disk with a circumferential surface texture, under various humidities. In Part II, we develop a theoretical formulation of the meniscus force of elliptical contact at isolated liquid bridges. This model predicts that the mean real pressure due to the meniscus force apparently decreases the net real contact pressure pr and increases the frictional coefficient. This effect becomes significant when the relative surface energy of the liquid 2γ/σ is comparable to pr, where σ is the standard deviation of asperity height distribution. When the disk is covered with lubricant and the liquid bridges are connected with each other, the solid noncontacting asperities play an important role in the formation of the meniscus force, and the relative lubricant thickness t/σ is the critical factor determining the friction.

The Study on Objective Evaluation of Occlusal Contact. Part. 1. The Similarity and Quantity of Each Tooth and Occlusal Patterns (Intercuspal Position).

1997 ◽  
Vol 41 (5) ◽  
pp. 822-829
Author(s):  
Makoto Takenaka ◽  
Yutaka Ito ◽  
Shigemitsu Sakuma ◽  
Yoshinori Mukaida ◽  
Kentaro Nakamura ◽  
...  
Keyword(s):  
Objective Evaluation ◽  
Occlusal Contact ◽  
Contact Part

Microstructure and nanohardness of Ag and Ni under friction in boundary lubrication

Wear ◽  
2018 ◽  
Vol 404-405 ◽  
pp. 62-70 ◽  
Author(s):  
Inna Popov ◽  
Alexey Moshkovich ◽  
Sidney R. Cohen ◽  
Vladislav Perfilyev ◽  
Atzmon Vakahy ◽  
...  
Keyword(s):  
Boundary Lubrication

scholarly journals Random Assignment Problems on 2d Manifolds

2021 ◽  
Vol 183 (2) ◽  
Author(s):  
D. Benedetto ◽  
E. Caglioti ◽  
S. Caracciolo ◽  
M. D’Achille ◽  
G. Sicuro ◽  
...  
Keyword(s):  
Assignment Problem ◽  
Unit Area ◽  
Constant Term ◽  
Beltrami Operator ◽  
Explicit Calculation ◽  
Dimensional Manifold ◽  
Two Dimensional ◽  
Random Assignment ◽  
Assignment Problems ◽  
Theoretical Formulation

AbstractWe consider the assignment problem between two sets of N random points on a smooth, two-dimensional manifold $$\Omega $$ Ω of unit area. It is known that the average cost scales as $$E_{\Omega }(N)\sim {1}/{2\pi }\ln N$$ E Ω ( N ) ∼ 1 / 2 π ln N with a correction that is at most of order $$\sqrt{\ln N\ln \ln N}$$ ln N ln ln N . In this paper, we show that, within the linearization approximation of the field-theoretical formulation of the problem, the first $$\Omega $$ Ω -dependent correction is on the constant term, and can be exactly computed from the spectrum of the Laplace–Beltrami operator on $$\Omega $$ Ω . We perform the explicit calculation of this constant for various families of surfaces, and compare our predictions with extensive numerics.

Robust Interfacial Tribofilms by Borate- and Polymer-Coated ZnO Nanoparticles Leading to Improved Wear Protection under a Boundary Lubrication Regime

Langmuir ◽  
2021 ◽  
Vol 37 (5) ◽  
pp. 1743-1759 ◽  
Author(s):  
Kimaya Vyavhare ◽  
Richard B. Timmons ◽  
Ali Erdemir ◽  
Brian L. Edwards ◽  
Pranesh B. Aswath
Keyword(s):  
Boundary Lubrication ◽  
Zno Nanoparticles ◽  
Wear Protection ◽  
Lubrication Regime

scholarly journals Does laser surface texturing really have a negative impact on the fatigue lifetime of mechanical components?

Friction ◽  
2021 ◽  
Author(s):  
Chia-Jui Hsu ◽  
Andreas Stratmann ◽  
Simon Medina ◽  
Georg Jacobs ◽  
Frank Mücklich ◽  
...  
Keyword(s):  
Boundary Lubrication ◽  
Surface Texturing ◽  
Contact Stresses ◽  
Laser Surface ◽  
Laser Surface Texturing ◽  
Wear Loss ◽  
Textured Surface ◽  
Periodic Patterns ◽  
Rolling Bearings ◽  
Fatigue Lifetime

AbstractLaser surface texturing (LST) has been proven to improve the tribological performance of machine elements. The micro-scale patterns manufactured by LST may act as lubricant reservoirs, thus supplying oil when encountering insufficient lubrication. However, not many studies have investigated the use of LST in the boundary lubrication regime, likely due to concerns of higher contact stresses that can occur with the increasing surface roughness. This study aims to examine the influence of LST on the fatigue lifetime of thrust rolling bearings under boundary lubrication. A series of periodic patterns were produced on the thrust rolling bearings, using two geometrically different designs, namely cross and dimple patterns. Base oil ISO VG 100 mixed with 0.05 wt% P of zinc dialkyldithiophosphate (ZDDP) was supplied. The bearings with cross patterns reduce the wear loss by two orders of magnitude. The patterns not only retain lubricant in the textured pockets but also enhance the formation of an anti-wear tribofilm. The tribofilm generation may be improved by the higher contact stresses that occur when using the textured surface. Therefore, in contrast to the negative concerns, the ball bearings with cross patterns were instead found to increase the fatigue life by a factor of three.

scholarly journals Pengaruh Penambahan Minyak Kelapa dan Sawit Terhadap Sifat Fisik dan Tribologi Pelumas SAE 40

Jurnal METTEK ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Dedison Gasni ◽  
KM Abdul Razak ◽  
Ahmad Ridwan ◽  
Muhammad Arif
Keyword(s):  
Fatty Acids ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Palm Oil ◽  
Boundary Lubrication ◽  
Viscosity Index ◽  
Coconut Oil ◽  
High Viscosity ◽  
Mineral Oil ◽  
Lubricating Oil

Penelitian ini bertujuan untuk mengetahui efek dari penambahan minyak kelapa dan sawit terhadap sifat fisik dan tribologi pelumas SAE 40. Vegetabel oil, seperti; minyak kelapa dan sawit, memiliki nilai viskositas indek yang tinggi dan sifat pelumasan yang baik terutama didaerah boundary lubrication jika dibandingkan dengan mineral oil (SAE 40). Hal ini disebabkan karena vegetabel oil memiliki kandungan fatty acids yang tidak dimiliki oleh mineral oil. Keunggulan lain dari minyak kelapa dan sawit adanya sifat yang ramah lingkungan karena mudah terurai di alam dan dapat diperbaharui. Pada penelitian ini sifat yang baik dari minyak kelapa dan sawit ini akan dimanfaatkan sebagai zat aditif pada minyak pelumas SAE 40. Pengujian dilakukan terhadap sifat fisik dan tribology dengan penambahan 5%, 10%, 15%, dan 20% berat dari minyak kelapa dan sawit ke dalam minyak pelumas SAE 40. Pengujian sifat fisik terdiri dari pengukuran viskositas pada temperatur 400C dan 1000C dan viskositas index. Pengujian sifat tribologi untuk menentukan keausan dan koefisien gesek berdasarkan ASTM G99 dengan menggunakan alat uji pin on disk. Dari hasil pengujian diperoleh bahwa dengan penambahan minyak kelapa dan sawit kedalam minyak pelumas SAE 40 terjadi peningkatan viskositas indeks. Peningkatan viskositas indeks sebanyak  17% dengan penambahan 20% minyak sawit. Terjadi perubahan sifat tribologi dengan penambahan minyak sawit, berupa penurunan keausan dan nilai koefisien gesek dibandingkan dengan penambahan minyak kelapa. This study aims to determine the effect of coconut and palm oils as additives to physical and tribological properties of SAE 40 lubricating oil . Vegetable oils, such as; coconut oil and palm oil, have high viscosity index and good lubrication properties, especially in boundary lubrication compared to mineral oil. This is due to vegetable oil having fatty acids that are not owned by mineral oil. The advantages of coconut oil and palm oil are environmentally friendly properties because they are biodegradable and renewable. In this study, the good properties of coconut and palm oils will be used as additives in SAE 40 lubricating oil. Tests are carried out on the physical and tribological properties with the addition of 5%, 10%, 15%, and 20% by weight of coconut and palm oils into SAE 40 lubricating oil. Physical properties testing consists of measuring viscosity at temperatures of 400C and 1000C and viscosity index. The tribological test is to determine wear and coefficient of friction based on ASTM G99 using a pin on disc test equipment. From the test results,  it was found that coconut and palm oils as additives into SAE 40 lubricating oil could increase in viscosity index. The increase of  the viscosity index was 17% by adding 20% of palm oil. There was a change of tribological properties in the form of decreasing on the wear and the coefficient of friction with the addition of palm oil compare to addition of coconut oil.

Sign in / Sign up

Export Citation Format

Share Document