Wear Quantification

1999 ◽  
Vol 122 (3) ◽  
pp. 650-656 ◽  
Author(s):  
A. Ravikiran
Keyword(s):  
Wear Rate ◽  
Material Properties ◽  
Industrial Applications ◽  
Improved Method ◽  
Experimental Conditions ◽  
General Consensus ◽  
Benchmark Tests ◽  
Pin On Disc ◽  
Improve Correlation ◽  
The Way

Tribology literature shows considerable scatter in the wear rate of materials obtained by pin-on-disc type of studies. The general consensus thus far has been that this scatter is due to variations in the material properties and experimental conditions used by different investigators. However, the present paper shows that the scatter can also arise from the way wear is quantified by popular methods such as by m3/m, m3/Nm and so on. Therefore, an improved method of wear quantification indicated as “wear index” (WI) a non-dimensional quantity, has been proposed and it is expected to reduce scatter that arises from the way wear is quantified. Evidence for the improvement has been provided from the results obtained from the experiments reported in this paper as well as those reported by different researchers. Besides reducing scatter, WI is expected to improve correlation in the wear values between laboratory benchmark tests and actual industrial applications, and also that between different investigators. Hence WI is expected to enhance the general understanding on tribology. [S0742-4787(00)01103-6]

scholarly journals Tribological Characteristics of Modified Hypo Eutectic Al-Si Alloy

2018 ◽  
Vol 778 ◽  
pp. 3-8 ◽  
Author(s):  
Sajawal Hussain ◽  
Muhammad Mansoor ◽  
Rehan Qayyume ◽  
Shaheed Khan
Keyword(s):  
Wear Rate ◽  
Coefficient Of Friction ◽  
Secondary Phase ◽  
Industrial Applications ◽  
Tribological Characteristics ◽  
Eutectic System ◽  
Modify Alloy ◽  
Pin On Disc ◽  
The Coefficient Of Friction ◽  
Cast Alloys

Al-Si eutectic system is a class [Mansoor, 2014 #24] of important cast alloys accounting for the majority of aluminum parts for different industrial applications. However, in unmodified form, it attributes to the lower mechanical strength, ductility and wear characteristics. In present work, Al-9 wt. %Si alloy was prepared in unmodified and modified form, where modification was carried out using mixtures of transitional earth halides. The modification process rectified the needle like silicon rich secondary phase into acicular shape, whose effect upon the tribological characteristic of the alloy were studied using pin-on-disc method. It was found that the coefficient of friction was reduced in modified alloy, besides lowering the wear rate. The main feature of wear scar was laminates. In case of modify alloy the laminates were of uniformly formed small sized, as opposed to non-uniform predominately large sized smooth segments with cracked edges. It was postulated that these non-uniform smooth laminates were formed due to smearing resulted in high coefficient of friction and wear rate. The altered tribological characteristics were attributed to the morphology of the silicon rich secondary phase i.e. the acicular shape.

scholarly journals Comparative Study on the Frequency and Wear of Thermoplastic Polymeric Materials Based on PTFE

2021 ◽  
Vol 58 (2) ◽  
pp. 33-40
Author(s):  
Ivona Camelia Petre ◽  
Elena Valentina Stoian ◽  
Maria Cristiana Enescu ◽  
Carmen Otilia Rusanescu
Keyword(s):  
Wear Rate ◽  
High Performance ◽  
Wear Behavior ◽  
Polymeric Materials ◽  
Basic Material ◽  
Low Friction ◽  
Experimental Conditions ◽  
Sliding Speed ◽  
Pin On Disc ◽  
The Coefficient Of Friction

The widespread use of thermoplastic polymeric materials in various industrial fields has shown considerable interest in understanding the frictional and wear behavior. Among these polymers, polytetrafluoroethylene, also called PTFE, is a high-performance plastic that offers high chemical and thermal resistance and low friction. Additives such as fiberglass, carbon and graphite fillers are added to PTFE to significantly increase thermal conductivity, stiffness and self-lubricating properties. The materials subjected to the experimental analysis were pure PTFE, PTFE + 15% fiberglass, PTFE + carbon-graphite which slipped, under conditions of dry friction, on a sample of non-alloy steel construction SR EN 10025 from 1994. The tests were performed on a pin-on-disc tribometer. The effect of loading and sliding speed on the tribological properties of the polymer / steel combination under dry slip conditions was investigated and the specific wear rate for the experimental conditions was evaluated. The tests were performed at loads of the pin of Fn1=1N, Fn2=3N, Fn3=5N and Fn4=10N and sliding speeds of 1=1m/s, 2=3m/s. The results obtained indicated that the coefficient of friction decreases with increasing load. The wear rate for the analyzed materials was between 10-13...10-15 m2/N, the fiberglass reinforced PTFE material having the lowest wear rate. The present paper, through a comparative analysis of the friction and wear behavior, highlights the effects that the ingredients introduced in the basic material have, under the action of the exploitation factors (loading, sliding speed).

The mensuration of interfaces

1992 ◽  
Vol 50 (1) ◽  
pp. 216-217
Author(s):  
W.M. Stobbs
Keyword(s):  
Electron Microscopy ◽  
50Th Anniversary ◽  
Numerical Data ◽  
Industrial Applications ◽  
Dynamical Theory ◽  
Large Strains ◽  
Reasonable Approach ◽  
Lattice Resolution ◽  
Analogue To Digital ◽  
The Way

I do not have access to the abstracts of the first meeting of EMSA but at this, the 50th Anniversary meeting of the Electron Microscopy Society of America, I have an excuse to consider the historical origins of the approaches we take to the use of electron microscopy for the characterisation of materials. I have myself been actively involved in the use of TEM for the characterisation of heterogeneities for little more than half of that period. My own view is that it was between the 3rd International Meeting at London, and the 1956 Stockholm meeting, the first of the European series , that the foundations of the approaches we now take to the characterisation of a material using the TEM were laid down. (This was 10 years before I took dynamical theory to be etched in stone.) It was at the 1956 meeting that Menter showed lattice resolution images of sodium faujasite and Hirsch, Home and Whelan showed images of dislocations in the XlVth session on “metallography and other industrial applications”. I have always incidentally been delighted by the way the latter authors misinterpreted astonishingly clear thickness fringes in a beaten (”) foil of Al as being contrast due to “large strains”, an error which they corrected with admirable rapidity as the theory developed. At the London meeting the research described covered a broad range of approaches, including many that are only now being rediscovered as worth further effort: however such is the power of “the image” to persuade that the above two papers set trends which influence, perhaps too strongly, the approaches we take now. Menter was clear that the way the planes in his image tended to be curved was associated with the imaging conditions rather than with lattice strains, and yet it now seems to be common practice to assume that the dots in an “atomic resolution image” can faithfully represent the variations in atomic spacing at a localised defect. Even when the more reasonable approach is taken of matching the image details with a computed simulation for an assumed model, the non-uniqueness of the interpreted fit seems to be rather rarely appreciated. Hirsch et al., on the other hand, made a point of using their images to get numerical data on characteristics of the specimen they examined, such as its dislocation density, which would not be expected to be influenced by uncertainties in the contrast. Nonetheless the trends were set with microscope manufacturers producing higher and higher resolution microscopes, while the blind faith of the users in the image produced as being a near directly interpretable representation of reality seems to have increased rather than been generally questioned. But if we want to test structural models we need numbers and it is the analogue to digital conversion of the information in the image which is required.

Variable Parameter Processes of Micro-Arc Oxidation for Aluminium Alloy

2011 ◽  
Vol 704-705 ◽  
pp. 1273-1278
Author(s):  
Cheng Gao ◽  
Jin Yong Xu ◽  
Xuan Yi Shi ◽  
Ya Juan Liu ◽  
Jing Chun Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Wear Rate ◽  
Ceramic Coating ◽  
Early Stage ◽  
Variable Parameter ◽  
Ceramic Coatings ◽  
Constant Current ◽  
Constant Voltage ◽  
Micro Arc Oxidation ◽  
The Way

In micro-arc oxidation process, ceramic coating had a rapid growth all along by the way of constant current oxidation, and ceramic coating had a low roughness by the way of constant voltage oxidation. But few research focus on the mixed control process of constant current oxidation and constant voltage oxidation. In this paper we propose a variable parameter process that can combine the advantages of constant current and constant voltage oxidation for the first time. The growth kinetics of different technics was analyzed according to the change law of current and voltage. Surface topographs of ceramic coating were observed using scanning electron microscopy (SEM). The friction tests were carried out using a self-made friction tester. The results show that ceramic coating has an upper growth rate and a low roughness by the process of constant current+constant voltage oxidation. The ceramic coating has a high growth rate by process of constant voltage+constant current oxidation. The results of friction test indicate that the wear rate and roughness of ceramic coating are positive correlation at early stage of friction. While the ceramic coatings treated by different technics have the close wear rate at stable friction stage, which embodies the inner layer of ceramic coating has a well antiwear behavior.

Evaluation of changes in mechanical properties of O-ring in one-piece and two-piece ball retained implant-supported overdentures: A three-year retrospective study.

2021 ◽  
Author(s):  
Fathima Banu Raza ◽  
Anand Kumar
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Retrospective Study ◽  
Statistical Analysis ◽  
Wear Rate ◽  
Digital Camera ◽  
Maximum Displacement ◽  
Pin On Disc ◽  
The One ◽  
Insight Into

The o-rings in ball retained overdentures deteriorate with time and need replacement to restore the retentive quality. We evaluated retrospectively the mechanical properties of o-rings after 3 years in function in one and two-piece implant-supported overdentures. The o-rings were retrieved from one-piece (Myriad snap, Equinox-Straumann, 3.3 x 13mm) and two-piece (Neo Biotech, 3.3 x 13mm) implant-supported overdenture patients. A total of 16 pairs of matrices were tested for wear, type of damage and elasticity using Pin on Disc method, USB Digital Camera in 30x zoom and Universal Tensile Machine respectively. The statistical analysis for independent groups were done with the Mann-Whitney U test. Assessment of used O-rings showed 84% more wear in the two-piece system with an abrasive type of damage while 46% wear in the one-piece system with a compressive type of damage. The o-rings in one-piece system showed increase in elongation and maximum displacement to 2% and 7% respectively, while two-piece system showed decrease in elongation and maximum displacement by 13% and 6% respectively. In one-piece system, the loss of retention was more with slow wear rate and in two-piece system, the wear resistance of O-rings decreased due to increased stiffness. Further studies to evaluate the changes in O-ring with increased sample size and at interval 1 year will pave way for insight into the progressive changes in the mechanical properties of an O-ring.

A study on tribological behaviour and analysis of ZnO reinforced AA6061 matrix composites fabricated by stir casting route

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sakthi Sadhasivam RM ◽  
Ramanathan K. ◽  
Bhuvaneswari B.V. ◽  
Raja R.
Keyword(s):  
Wear Rate ◽  
Sliding Wear ◽  
Stir Casting ◽  
Industrial Applications ◽  
Wear Behaviour ◽  
Matrix Composites ◽  
Tribological Behaviour ◽  
Content Type ◽  
Zno Particles ◽  
The Matrix

Purpose The most promising replacements for the industrial applications are particle reinforced metal matrix composites because of their good and combined mechanical properties. Currently, the need of matrix materials for industrial applications is widely satisfied by aluminium alloys. The purpose of this paper is to evaluate the tribological behaviour of the zinc oxide (ZnO) particles reinforced AA6061 composites prepared by stir casting route. Design/methodology/approach In this study, AA6061 aluminium alloy matrix reinforced with varying weight percentages (3%, 4.5% and 6%) of ZnO particles, including monolithic AA6061 alloy samples, is cast by the most economical fabrication method, called stir casting. The prepared sample was subjected to X-ray photoelectron spectroscopy (XPS) analysis, experimental density measurement by Archimedian principle and theoretical density by rule of mixture and hardness test to investigate mechanical property. The dry sliding wear behaviour of the composites was investigated using pin-on-disc tribometer with various applied loads of 15 and 20 N, with constant sliding velocity and distance. The wear rate, coefficient of friction (COF) and worn surfaces of the composite specimens and their effects were also investigated in this work. Findings XPS results confirm the homogeneous distribution of ZnO microparticles in the Al matrix. The Vickers hardness result reveals that higher ZnO reinforced (6%) sample have 34.4% higher values of HV than the monolithic aluminium sample. The sliding wear tests similarly show that increasing the weight percentage of ZnO particles leads to a reduced wear rate and COF of 30.01% and 26.32% lower than unreinforced alloy for 15 N and 36.35% and 25% for 20 N applied load. From the worn surface morphological studies, it was evidently noticed that ZnO particles dispersed throughout the matrix and it had strong bonding between the reinforcement and the matrix, which significantly reduced the plastic deformation of the surfaces. Originality/value The uniqueness of this work is to use the reinforcement of ZnO particles with AA6061 matrix and preparing by stir casting route and to study and analyse the physical, hardness and tribological behaviour of the composite materials.

scholarly journals OPTIMIZATION OF TRIBOLOGICAL PROPERTIES OF AN EPOXY HYBRID POLYMER COMPOSITE REINFORCED WITH ZrB2 AND PTFE PARTICLES USING RESPONSE SURFACE METHODOLOGY FOR HIGH-TEMPERATURE TRIBOLOGICAL APPLICATIONS

2021 ◽  
Vol 55 (6) ◽  
Author(s):  
Aswathi A. Narayanan ◽  
R. S. Sudheesh
Keyword(s):  
Response Surface Methodology ◽  
High Temperature ◽  
Wear Rate ◽  
Response Surface ◽  
Tribological Properties ◽  
Epoxy Composites ◽  
Liner Material ◽  
Spherical Bearing ◽  
Pin On Disc ◽  
Hybrid Polymer Composite

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.

Heat Transfer and Pressure Drop for Flow Boiling of Water in Narrow Vertical Rectangular Channels

2003 ◽  
Author(s):  
Jianyun Shuai ◽  
Rudi Kulenovic ◽  
Manfred Groll
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Flow Boiling ◽  
Bubbly Flow ◽  
High Heat ◽  
Flow Patterns ◽  
Industrial Applications ◽  
Heat Fluxes ◽  
Experimental Conditions ◽  
Rectangular Channels

Flow boiling in small-sized channels attracted extensive investigations in the past two decades due to special requirements for transfer of high heat fluxes from narrow spaces in various industrial applications. Experiments on various aspects of flow boiling in narrow channels were carried out and theoretical attempts were undertaken. But these investigations showed large differences, e.g. up till now the knowledge on the development of flow patterns in small non-circular flow passages is very limited. This paper deals with investigations on flow boiling of water in two rectangular channels with dimensions (width×depth) 2.0×4.0 mm2 and 0.5×2.0 mm2 (corresponding hydraulic diameters are 2.67 mm and 0.8 mm). The pressure at the test section exit is atmospheric. For steady-state experimental conditions the effects of heat flux, mass flux and inlet subcooling on the boiling heat transfer coefficient and the pressure drop are investigated. Flow patterns and the transition of flow patterns along the channel axis are visualized and documented with a video-camera. Bubbly flow, slug flow and annular flow are distinguished in both channels. Preliminary flow pattern maps are generated.

scholarly journals Fault Diagnosis of Rotating Machinery under Noisy Environment Conditions Based on a 1-D Convolutional Autoencoder and 1-D Convolutional Neural Network

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 972 ◽  
Author(s):  
Xingchen Liu ◽  
Qicai Zhou ◽  
Jiong Zhao ◽  
Hehong Shen ◽  
Xiaolei Xiong
Keyword(s):  
Neural Network ◽  
Fault Diagnosis ◽  
Convolutional Neural Network ◽  
Industrial Applications ◽  
Experimental Result ◽  
Noisy Environment ◽  
Experimental Conditions ◽  
Global Average ◽  
Noisy Input ◽  
Convolutional Autoencoder

Deep learning methods have been widely used in the field of intelligent fault diagnosis due to their powerful feature learning and classification capabilities. However, it is easy to overfit depth models because of the large number of parameters brought by the multilayer-structure. As a result, the methods with excellent performance under experimental conditions may severely degrade under noisy environment conditions, which are ubiquitous in practical industrial applications. In this paper, a novel method combining a one-dimensional (1-D) denoising convolutional autoencoder (DCAE) and a 1-D convolutional neural network (CNN) is proposed to address this problem, whereby the former is used for noise reduction of raw vibration signals and the latter for fault diagnosis using the de-noised signals. The DCAE model is trained with noisy input for denoising learning. In the CNN model, a global average pooling layer, instead of fully-connected layers, is applied as a classifier to reduce the number of parameters and the risk of overfitting. In addition, randomly corrupted signals are adopted as training samples to improve the anti-noise diagnosis ability. The proposed method is validated by bearing and gearbox datasets mixed with Gaussian noise. The experimental result shows that the proposed DCAE model is effective in denoising and almost causes no loss of input information, while the using of global average pooling and input-corrupt training improves the anti-noise ability of the CNN model. As a result, the method combined the DCAE model and the CNN model can realize high-accuracy diagnosis even under noisy environment.

Friction Coefficient and Wear Rate of Different Materials Sliding Against Stainless Steel

2013 ◽  
Vol 1 (1) ◽  
pp. 33-45 ◽  
Author(s):  
Dewan Muhammad Nuruzzaman ◽  
Mohammad Asaduzzaman Chowdhury
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Normal Load ◽  
304 Stainless Steel ◽  
Sliding Velocity ◽  
Stainless Steel 304 ◽  
Different Types ◽  
Pin On Disc ◽  
Ss 304

This paper examines the relation between friction/wear and different types of steel materials under different normal loads and sliding velocities and to explore the possibility of adding controlled normal load and sliding velocity to a mechanical process. In order to do so, a pin on disc apparatus is designed and fabricated. Experiments are carried out when different types of disc materials such as stainless steel 304 (SS 304), stainless steel 316 (SS 316) and mild steel slide against stainless steel 304 (SS 304) pin. Variations of friction coefficient with the duration of rubbing at different normal loads and sliding velocities are investigated. Results show that friction coefficient varies with duration of rubbing, normal load and sliding velocity. In general, friction coefficient increases for a certain duration of rubbing and after that it remains constant for the rest of the experimental time. The obtained results reveal that friction coefficient decreases with the increase in normal load for all the tested materials. It is also found that friction coefficient increases with the increase in sliding velocity for all the materials investigated. Moreover, wear rate increases with the increase in normal load and sliding velocity. At identical operating condition, the magnitudes of friction coefficient and wear rate are different for different materials depending on sliding velocity and normal load.

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