scholarly journals Predicting and analyzing of tribo-performance of NAO friction composites using Taguchi method

Author(s):  
Fikrat Yusubov

Abstract The present study is aimed to investigate the dry sliding behavior of phenolic friction brake pad materials for industrial applications. Low metallic phenolic friction composites with addition copper-graphite (Cu-C) particles produced by traditional powder metallurgy methods. The friction test is carried out by pin-on-disc configuration on universal tribometer MMW-1 with hardened steel as a counterface material. The plan of experiments conducted by Taguchi’s L27 orthogonal array on MINITAB 19.1.1 software using 3-level design model. Analysis of variance (ANOVA) was performed for predicting and analyzing the effect of design parameters like contact pressure (1.9, 5.75 and 9,6 MPa), sliding velocity (0.64, 1.57 and 2.5 m/s) and filler content (5, 10 and 15%) to tribological properties. Results of modeling and optimization of composites has showed that contact pressure has the greatest impact on the friction process following sliding distance and filler content. On the other hand, the most influential factor for the wear process was the sliding velocity, following contact pressure and finally filler content. It has also been determined that 5–10 Wt.% Cu-C filler content has an effective impact on tribological properties. The friction surface examination of the composites using a scanning electron microscope (SEM) revealed that Cu-C content has a significant effect on improving heat resistance properties.

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7318
Author(s):  
Anita Ptak ◽  
Paula Taciak ◽  
Wojciech Wieleba

This article concerns the tribological properties of three selected polymer materials: polyamide PA6, polyethylene PE-HD and polyetheretherketone composite PEEK/BG during sliding against aluminium alloy EN AW-2017A in the presence of hydraulic oil HLP 68. The tests were carried out under contact pressure p of 3.5–11 MPa at ambient temperature T ranging from −20 °C to +20 °C. The dependence of kinetic friction coefficient μk on the two parameters was determined through tribological tests carried out using a pin-on-disc tribometer. A five-level central composite rotatable design (CCRD) was adopted for the experiment. All the test results were statistically analysed. The microhardness of the surface of the polymeric material was measured before and after the friction process. The surface was also examined under SEM. Temperature and contact pressure have been found to have a significant effect on the tribological properties of the tested sliding pairs. Relative to the applied friction conditions, the surfaces after friction showed rather heavy signs of wear.


2014 ◽  
Vol 984-985 ◽  
pp. 304-312 ◽  
Author(s):  
Ponnambalam Balamurugan ◽  
Marimuthu Uthayakumar

Copper base composites are extensively used in applications where high temperature and corrosive environment. In the present investigation a hybrid metal matrix composite is prepared in which copper is used as a matrix, SiC and Fly ash as reinforcements. The composite is produced by powder metallurgy technique. Dry sliding wear characteristics of the prepared composite specimes were studied by pin on disc setup and optimised result was found through grey relational analysis. Analysis of variance is used to investigate the significance of design parameters which affect the wear characteristic of the materials. The results showed that sliding velocity is having the significant effect than the other parameters.


Author(s):  
C J R Sheppard

The confocal microscope is now widely used in both biomedical and industrial applications for imaging, in three dimensions, objects with appreciable depth. There are now a range of different microscopes on the market, which have adopted a variety of different designs. The aim of this paper is to explore the effects on imaging performance of design parameters including the method of scanning, the type of detector, and the size and shape of the confocal aperture.It is becoming apparent that there is no such thing as an ideal confocal microscope: all systems have limitations and the best compromise depends on what the microscope is used for and how it is used. The most important compromise at present is between image quality and speed of scanning, which is particularly apparent when imaging with very weak signals. If great speed is not of importance, then the fundamental limitation for fluorescence imaging is the detection of sufficient numbers of photons before the fluorochrome bleaches.


Lubricants ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 9
Author(s):  
Ahmed Nabhan ◽  
Ahmed Rashed ◽  
Nouby M. Ghazaly ◽  
Jamil Abdo ◽  
M. Danish Haneef

The tribological properties of Lithium grease specimens with different concentrations of Al2O3 nanoparticles were investigated using a pin on disc apparatus under different sliding speeds and normal loads. Results showed that Al2O3 nanoparticles enhanced the tribological properties of lithium grease and reduced the COF and wear scar width by approximately 57.9% and 47.5% respectively.


Author(s):  
Anup Darshan ◽  
UmaMaheshwera Reddy Paturi ◽  
Narala Suresh Kumar Reddy ◽  
Srinivasa Prakash Regalla

Now a days for machining operations apart from good tribological properties, the lubricant is also expected to be non-hazardous and non-polluting. When considering the ecological and environmental aspects in machining processes, the use of biodegradable oil can be an alternative source of lubricant due to its positive impact to employee health and environmental pollution. In this regard, our research work uses vegetable based cutting fluids developed from canola and sunflower oil, in an attempt to provide an eco-friendly environment. Experiments are carried out on a pin-on-disc tribometer with tungsten carbide (WC) pin against AISI 4340 steel disc for different sliding times under different environments, thus simulating the machining environment. The tribological properties, wear and friction of vegetable based oils were comparatively investigated with a commercially available mineral oil. Wear tracks and roughness profiles of test specimens were compared by using optical microscope and profilometer respectively. Results indicated that vegetable based canola oil demonstrated excellent tribological properties compared to that of commercial mineral oil.


2021 ◽  
Author(s):  
Domenico Tommasino ◽  
Matteo Bottin ◽  
Giulio Cipriani ◽  
Alberto Doria ◽  
Giulio Rosati

Abstract In robotics the risk of collisions is present both in industrial applications and in remote handling. If a collision occurs, the impact may damage both the robot and external equipment, which may result in successive imprecise robot tasks or line stops, reducing robot efficiency. As a result, appropriate collision avoidance algorithms should be used or, if it is not possible, the robot must be able to react to impacts reducing the contact forces. For this purpose, this paper focuses on the development of a special end-effector that can withstand impacts and is able to protect the robot from impulsive forces. The novel end-effector is based on a bi-stable mechanism that decouples the dynamics of the end-effector from the dynamics of the robot. The intrinsically non-linear behavior of the end-effector is investigated with the aid of numerical simulations. The effect of design parameters and the operating conditions are analyzed and the interaction between the functioning of the bi-stable mechanism and the control system is studied. In particular, the effect of the mechanism in different scenarios characterized by different robot velocities is shown. Results of numerical simulations assess the validity of the proposed end-effector, which can lead to large reductions in impact forces.


Author(s):  
Lozica Ivanović ◽  
Miloš Matejić

Gerotor pumps are well known by a compact design, simple structure and low noise level, which makes them suitable for use in the automotive industry, and especially in hydraulic systems for engine lubrication. One of the main disadvantages of gerotor pumps is the inability to adjust to wear, which significantly reduces the pump efficiency. In order to mitigate the negative effect of the inevitable wear process, this paper presents a methodology for determining the optimal combination of trochoid gears design parameters for a defined aspect. An appropriate mathematical model has been developed to analyze the effect of changes in gear design parameters in relation to maximum contact stresses, pressure changes in gerotor pump chambers and wear rate proportional factor (WRPF). Verification of the developed models was performed by realizing physical pairs of gears and laboratory experiments with simulation of pump operating conditions. The results and conclusions presented in this paper, with an emphasis on the actual work processes, bring very important perspectives for the gerotor pumps design with improved performance.


2021 ◽  
Vol 55 (6) ◽  
Author(s):  
Aswathi A. Narayanan ◽  
R. S. Sudheesh

Hybrid PTFE/epoxy composites are widely used as materials for self-lubricating spherical bearing which are used in a high-temperature environment. In the present work, zirconium diboride (ZrB2) particles are incorporated to enhance high-temperature tribological properties of PTFE/epoxy composites. Pin on disc experiment is conducted with the aid of design of experiments (DOE) using central composite-response surface methodology (RSM). Under a load of 40 N and 1.25 m/s sliding speed, the optimum content 5.95 vol% of PTFE and 5.05 vol% of ZrB2, yields an ultralow coefficient of friction (COF) in conjunction with a low wear rate of the composite. The addition of ultra-high-temperature ceramic ZrB2 particles and solid lubricant PTFE is found to enhance the thermal conductivity and improve the heat transfer thereby reducing contact temperature. The use of optimum composition of the composite is capable of reducing the wear rate and high local temperature due to friction, implying its potential use as a self-lubricating spherical bearing liner material.


2020 ◽  
Vol 37 (1−2) ◽  
Author(s):  
SRIDHAR ATLA ◽  
Prasanna Lakshmi Kaujala

The aluminium metal matrix composite reinforced with ceramic material of Silicon carbide (SiC) has good mechanical properties. However, aluminium based ceramic composites require improvements in their lubrication and tribological properties. In this study an attempt is made in the development of a new material through powder metallurgy technique by the addition of Graphite, which acts as a solid lubricant. This work investigated the influence of graphite on the wear behaviour of Al 7075/SiC /X wt.% graphite(X=0, 5 and 10) hybrid composite. The investigation reveals the effectiveness of incorporation of graphite in the composite for gaining wear reduction. The Al 7075 (aluminium alloy 7075) reinforced with SiC –graphite were investigated. The composites were fabricated using powder metallurgy route. The microstructures, material combination, wear and friction properties were analysed by scanning electron microscopy, XRD, and pin-on-disc wear tester. The newly developed aluminium composite has significant improvements in tribological properties with a combination of 5% Silicon carbide (SiC) and 5% Graphite. The test reveals that sliding distance of 1000 m and sliding speed of 1.5 m/s with applied load of 5 N result in minimum wear loss of 0.01062g and coefficient of friction as 0.1278.


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