scholarly journals Analysis of the hardness ratio effect on the tribological performance of NiCrBSi coating/debris particles using the Stribeck Curve

Wear ◽  
2021 ◽  
Vol 486-487 ◽  
pp. 204081
Author(s):  
K.A. Habib ◽  
D.L. Cano ◽  
José Antonio Heredia ◽  
J. Serrano-Mira
Keyword(s):  
Tribological Performance ◽  
Stribeck Curve ◽  
Ratio Effect ◽  
Debris Particles ◽  
Nicrbsi Coating ◽  
Hardness Ratio

scholarly journals Two-scale homogenization of hydrodynamic lubrication in a mechanical seal with isotropic roughness based on the Elrod cavitation algorithm

2021 ◽  
pp. 135065012110176
Author(s):  
Yanxiang Han ◽  
Qingen Meng ◽  
Gregory de Boer
Keyword(s):  
Surface Topography ◽  
Carrying Capacity ◽  
Hydrodynamic Lubrication ◽  
Tribological Performance ◽  
Stribeck Curve ◽  
Polar Coordinate System ◽  
Load Carrying Capacity ◽  
Mechanical Seal ◽  
Macro Scale ◽  
Load Carrying

A two-scale homogenization method for modelling the hydrodynamic lubrication of mechanical seals with isotropic roughness was developed and presented the influence of surface topography coupled into the lubricating domain. A linearization approach was derived to link the effects of surface topography across disparate scales. Solutions were calculated in a polar coordinate system derived based on the Elrod cavitation algorithm and were determined using homogenization of periodic simulations describing the lubrication of a series of surface topographical features. Solutions obtained for the hydrodynamic lubrication regime showed that the two-scale homogenization approach agreed well with lubrication theory in the case without topography. Varying topography amplitude demonstrated that the presence of surface topography improved tribological performance for a mechanical seal in terms of increasing load-carrying capacity and reducing friction coefficient in the radial direction. A Stribeck curve analysis was conducted, which indicated that including surface topography led to an increase in load-carrying capacity and a reduction in friction. A study of macro-scale surface waviness showed that the micro-scale variations observed were smaller in magnitude but cannot be obtained without the two-scale method and cause significant changes in the tribological performance.

scholarly journals Tribological Properties of Polyether–Ether–Ketone-Based Coating under Mixed and Boundary Aviation Kerosene-Lubrication Condition

Coatings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 1
Author(s):  
Jihai Jiang ◽  
Cunran Zhao ◽  
Geqiang Li
Keyword(s):  
Constant Load ◽  
Tribological Performance ◽  
Stribeck Curve ◽  
Aviation Kerosene ◽  
Polyether Ether Ketone ◽  
Tin Bronze ◽  
Lubrication Condition ◽  
Ether Ketone ◽  
Low Wear ◽  
Lubrication Conditions

Because of its excellent tribological performance, polyether–ether–ketone (PEEK)-based coatings have been used extensively under mixed and boundary water-lubrication conditions. To verify that the PEEK-based coating is applicable to aviation kerosene, one advanced coating was proposed and two typical metals, namely, alloy steel 38CrMoAlA and tin bronze ZQPb17-4-4, were selected as counterparts. Four sets of experiments that involved a scuffing (step load) and Stribeck curve (step speed), constant load, and strengthened load were carried out, which showed that the counterpart material’s properties, such as its hardness, thermal conductivity, and composition, had an important effect on the tribological performance of the PEEK-based coating. Scuffing experiments showed that the PEEK-based coating against ZQPb17-4-4 exhibited better scuffing performance. Stribeck curve experiments showed that the PEEK-based coating against 38CrMoAlA was under the mixed lubrication condition over a wider range of speeds, and wear experiments (constant load and strengthened load) showed that the PEEK-based coating against 38CrMoAlA exhibited a relatively low coefficient of friction and low wear rate. The formation and appearance of the tribofilm on the surface of the counterparts influenced the wear mechanism of the PEEK-based coating. The PEEK-based coating showed excellent properties, especially when rubbed against 38CrMoAlA.

Tribological performance of avocado oil containing copper nanoparticles in mixed and boundary lubrication regime

2018 ◽  
Vol 70 (5) ◽  
pp. 865-871 ◽  
Author(s):  
Wani Khalid Shafi ◽  
Ankush Raina ◽  
Mir Irfan Ul Haq
Keyword(s):  
Film Formation ◽  
Tribological Performance ◽  
Stribeck Curve ◽  
Cu Nanoparticles ◽  
Content Type ◽  
Base Oil ◽  
Mineral Oils ◽  
Avocado Oil ◽  
Pin On Disc ◽  
Alloy 6061

Purpose This paper aims to study the tribological performance of Cu nanoparticles mixed in avocado oil. Design/methodology/approach A Pin-on-Disc tribometer was used to determine the tribological performance of avocado oil as a lubricant as well as for measuring the effectiveness of Cu nanoparticles. Stribeck curve was generated with the base oil and the oil containing Cu nanoparticles. The nanoparticles are added in 0.5 wt. % and 1 wt. % concentration. The worn-out surfaces of aluminum alloy 6061 pins are explored by scanning electron microscopy (SEM). Findings The use of Cu nanoparticles led to a reduction in friction and wear. Coefficient of friction (COF) was found to be minimum at 1 wt. % concentration, whereas specific wear rate was minimum for 0.5 wt. % concentration. The film-formation capability of the Cu nanoparticles led to an overall improvement in the tribological properties of the base oil. Originality/value Experiments are performed to evaluate the tribological performance of avocado oil using Cu nanoparticles. The results obtained herein suggest that avocado oil has a great potential to replace the conventional mineral oils in the field of industrial lubrication.

scholarly journals Wear Resistance of Medium Carbon Steel with Different Microstructures

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2015
Author(s):  
Xue Han ◽  
Zhenpu Zhang ◽  
Gary C. Barber ◽  
Steven J. Thrush ◽  
Xin Li
Keyword(s):  
Wear Resistance ◽  
Carbon Steel ◽  
Tribological Performance ◽  
Medium Carbon Steel ◽  
Tempered Martensite ◽  
Medium Carbon ◽  
Debris Particles ◽  
Quenched And Tempered Steel ◽  
Bainite Microstructure ◽  
Martensite Microstructure

In this research, the tribological properties of different microstructures of medium carbon steel produced by either an austempered process or quenched-tempered process are investigated. The as-received samples with annealed microstructure (spherodized) are austempered to obtain a bainite microstructure or quenched-tempered to obtain a tempered martensite microstructure. The tribological performance of these microstructures was studied using a ball-on-disk UMT3 tribometer. The results indicated that both bainite microstructures and tempered-martensite microstructures produced better wear resistance than pearlite microstructures. At the same hardness level, the austempered disk specimens have less cracking due to higher fracture toughness compared to quenched and tempered steel. For the disks, tempered martensite microstructures produced more plastic deformation compared with bainite microstructures. Mild abrasive wear was observed on the harder disks, however, smearing wear was observed on the softer disks. Adhered debris particles were observed on the balls.

Tribological Performance and Action Mechanism of Cadmium Dialkyldithiophosphate

2005 ◽  
Vol 48 (2) ◽  
pp. 171-175 ◽  
Author(s):  
Hu Jianqiang ◽  
Wei Xianyong ◽  
Yao Junbing ◽  
Xie Feng ◽  
Zhu Huanqin ◽  
...  
Keyword(s):  
Tribological Performance ◽  
Action Mechanism

PENGARUH PERPUTARAN PIUTANG DAN SOLVABILITAS TERHADAP KONDISI FINANCIAL DISTRESS PERUSAHAAN MANUFAKTUR SEKTOR GARMEN DAN TEKSTIL DI BURSA EFEK INDONESIA

2018 ◽  
Vol 19 (2) ◽  
pp. 87
Author(s):  
Siska Wulandari
Keyword(s):  
Financial Distress ◽  
Free Market ◽  
Linear Regression Analysis ◽  
Secondary Data ◽  
Multiple Linear Regression Analysis ◽  
Working Capital ◽  
Leverage Ratio ◽  
Ratio Effect ◽  
Waste Bank ◽  
Solvency Ratio

Manufacture Sub Sector Garment And Textile have financial distress condition. Increas of sales is one of choice for company can be competitive in free market. But increase of sales will be followed by the many possibilities of uncollected receivable or the low receivable turnover which can effect forced the company to further provide working capital. One way is to get working capital from a third part or what we call debt.This research aims to determine the effect of receivable turnover and the solvency ratio toward the financial distressThe problems of the research were: 1) is the receivable turnover effect toward financial distress condition on Garmen and textile company Listed on IDX on 2011-2015? 2) is the leverage ratio effect toward financial distress condition on Garmen and textile company Listed on IDX on 2011-2015 ? 3) Are the receivable turnover and solvency ratio effect toward financial distress condition on Garmen and textile company Listed on IDX on 2011-2015?The sample of this research is 11 Manufacture company of sub sector Garmen And Textile were taken by using purposive sampling techniques. This research data used secondary data that getting from literature review. Data were tested using multiple linear regression analysis to determine the effect between one variable with another variables, and the data was then processed using SPSS 22.0 for windows.Result of the research showed that partially, receivables turnover hadn’t a significant effect toward  the financial distress. Partially, solvency ratio (Debt to Asset) had a significant influence toward financial distress Simultaneously, receivable turnover and solvency ratio had a significant effect toward financial distress. Kata kunci:Waste Bank, Waste Bank Management, Waste Bank Basic Concepts, Economic Improvement of the Family

Integrating Visual and Bayesian Statistical Analyses in Single Case Experimental Research to Evaluate the Effectiveness and Magnitude of a Comprehensive Behavioral Intervention

2018 ◽  
Author(s):  
Prathiba Natesan ◽  
Smita Mehta
Keyword(s):  
Behavioral Intervention ◽  
Effect Size ◽  
Rate Ratio ◽  
Visual Analysis ◽  
Single Case ◽  
Small Sample ◽  
Statistical Analyses ◽  
Data Types ◽  
Ratio Effect ◽  
Small Sample Sizes

Single case experimental designs (SCEDs) have become an indispensable methodology where randomized control trials may be impossible or even inappropriate. However, the nature of SCED data presents challenges for both visual and statistical analyses. Small sample sizes, autocorrelations, data types, and design types render many parametric statistical analyses and maximum likelihood approaches ineffective. The presence of autocorrelation decreases interrater reliability in visual analysis. The purpose of the present study is to demonstrate a newly developed model called the Bayesian unknown change-point (BUCP) model which overcomes all the above-mentioned data analytic challenges. This is the first study to formulate and demonstrate rate ratio effect size for autocorrelated data, which has remained an open question in SCED research until now. This expository study also compares and contrasts the results from BUCP model with visual analysis, and rate ratio effect size with nonoverlap of all pairs (NAP) effect size. Data from a comprehensive behavioral intervention are used for the demonstration.

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