An Investigation of the Impacts of Contact Parameters on Wear Coefficient

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
V. Janakiraman ◽  
S. Li ◽  
A. Kahraman
Keyword(s):  
Surface Roughness ◽  
Point Contact ◽  
Viscosity Coefficient ◽  
Rolling Contact ◽  
Wear Coefficient ◽  
Wear Process ◽  
Contact Formulation ◽  
Model Combining ◽  
Roughness Amplitude ◽  
Disk Rolling

In this study, the wear depths under different loads, speeds, lubricant temperatures, and surface roughness amplitudes are experimentally determined using a twin-disk rolling contact setup. A point contact wear model combining a contact formulation and Archard's wear equation in an iterative manner is developed to simulate the wear process of the experiments. By matching the measured and predicted wear profiles, the wear coefficients under different operating and surface conditions are determined. It is found that the wear coefficient increases when either the load or the surface roughness amplitude increases and decreases as the lubricant pressure-viscosity coefficient increases. Within the operating ranges considered, it is observed that the lubricant pressure-viscosity coefficient is the most influential parameter on wear, the load has the least impact, and the surface roughness amplitude is in between. Lastly, a regression formula is given for the estimation of Archard's wear coefficient.

scholarly journals Remaining Useful Life Prediction of Cutting Tools Using an Inverse Gaussian Process Model

2021 ◽  
Vol 11 (11) ◽  
pp. 5011
Author(s):  
Yuanxing Huang ◽  
Zhiyuan Lu ◽  
Wei Dai ◽  
Weifang Zhang ◽  
Bin Wang
Keyword(s):  
Surface Roughness ◽  
Failure Criterion ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Remaining Useful Life ◽  
Model Parameters ◽  
Inverse Gaussian ◽  
Wear Process ◽  
Useful Life ◽  
Dynamic Wear

In manufacturing, cutting tools gradually wear out during the cutting process and decrease in cutting precision. A cutting tool has to be replaced if its degradation exceeds a certain threshold, which is determined by the required cutting precision. To effectively schedule production and maintenance actions, it is vital to model the wear process of cutting tools and predict their remaining useful life (RUL). However, it is difficult to determine the RUL of cutting tools with cutting precision as a failure criterion, as cutting precision is not directly measurable. This paper proposed a RUL prediction method for a cutting tool, developed based on a degradation model, with the roughness of the cutting surface as a failure criterion. The surface roughness was linked to the wearing process of a cutting tool through a random threshold, and accounts for the impact of the dynamic working environment and variable materials of working pieces. The wear process is modeled using a random-effects inverse Gaussian (IG) process. The degradation rate is assumed to be unit-specific, considering the dynamic wear mechanism and a heterogeneous population. To adaptively update the model parameters for online RUL prediction, an expectation–maximization (EM) algorithm has been developed. The proposed method is illustrated using an example study. The experiments were performed on specimens of 7109 aluminum alloy by milling in the normalized state. The results reveal that the proposed method effectively evaluates the RUL of cutting tools according to the specified surface roughness, therefore improving cutting quality and efficiency.

Predicting the wear coefficient and friction coefficient in dry point contact using continuum damage mechanics

2018 ◽  
Vol 233 (3) ◽  
pp. 447-455 ◽  
Author(s):  
Sahar Ghatrehsamani ◽  
Saleh Akbarzadeh
Keyword(s):  
Friction Coefficient ◽  
Damage Mechanics ◽  
Point Contact ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Wear Coefficient ◽  
Mechanics Model ◽  
Pin On Disk ◽  
Disk Test ◽  
The Continuum

Wear coefficient and friction coefficient are two of the key parameters in the performance of any tribo-system. The main purpose of the present research is to use continuum damage mechanics to predict wear coefficient. Thus, a contact model is utilized that can be used to obtain the friction coefficient between the contacting surfaces. By applying this model to the continuum damage mechanics model, the wear coefficient between dry surfaces is predicted. One of the advantages of using this model is that the wear coefficient can be numerically predicted unlike other methods which highly rely on experimental data. In order to verify the results predicted by this model, tests were performed using pin-on-disk test rig for several ST37 samples. The results indicated that the wear coefficient increases with increasing the friction coefficient.

Scale Effects in Generalized Newtonian Elastohydrodynamic Films

2008 ◽  
Author(s):  
I. I. Kudish ◽  
P. Kumar ◽  
M. M. Khonsary ◽  
S. Bair
Keyword(s):  
Film Thickness ◽  
Scale Effects ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Viscosity Coefficient ◽  
Shear Thinning ◽  
Effective Pressure ◽  
Practical Advantage ◽  
Inlet Zone ◽  
Real Machine

The prediction of elastohydrodynamic lubrication (EHL) film thickness requires knowledge of the lubricant properties. Today, in many instances, the properties have been obtained from a measurement of the central film thickness in an optical EHL point contact simulator and the assumption of a classical Newtonian film thickness formula. This technique has the practical advantage of using an effective pressure-viscosity coefficient which compensates for shear-thinning. We have shown by a perturbation analysis and by a full EHL numerical solution that the practice of extrapolating from a laboratory scale measurement of film thickness to the film thickness of an operating contact within a real machine may substantially overestimate the film thickness in the real machine if the machine scale is smaller and the lubricant is shear-thinning in the inlet zone.

Optimized Mapping of Pressure in Lubricated Point Contacts Based on Measured Film Thickness

2007 ◽  
Author(s):  
Radek Polisˇcˇuk ◽  
Michal Vaverka ◽  
Martin Vrbka ◽  
Ivan Krˇupka ◽  
Martin Hartl
Keyword(s):  
Film Thickness ◽  
Numerical Solution ◽  
Point Contact ◽  
Contact Fatigue ◽  
Lubricant Film ◽  
Rolling Contact ◽  
Experimental Film ◽  
Lubricated Contacts ◽  
Practical Performance ◽  
Traction Drives

The surface topography plays significant role in lifetime of highly loaded machine parts with lubricated contacts. Many elements like gears, rolling bearings, cams and traction drives operate in mixed lubrication conditions, where the lubricant film behavior closely implies the main practical performance parameters such as friction wear, contact fatigue and scuffing. For prediction of wear and especially contact fatigue, the values and distribution of the pressure in rolling contact are often required. The usual theoretical approach based on numerical solution of physical-mathematical models built around the Reynolds equation can be extremely time consuming, especially when lubricant films are very thin, and contact load and required resolution very high. This study presents a further refined approach to our previously published experimental method, based on on inverse elasticity theory and fast convolution transformation between the lubricant film thickness map and the pressure distribution within the point contact. The experimental film thickness maps of EHD lubricated contacts with smooth and dented surfaces were processed using colorimetric interferometry and validated using numerical solution, in order to calibrate numerical parameters and to find limits of the new approach.

Relating Surface Roughness to Subsurface Stress

2005 ◽  
Author(s):  
A. Martini ◽  
S. B. Liu ◽  
B. Escoffier ◽  
Q. Wang
Keyword(s):  
Surface Roughness ◽  
Stress Field ◽  
Point Contact ◽  
Surface Characteristics ◽  
Operating Conditions ◽  
Surface Design ◽  
Dry Contact ◽  
Subsurface Stress ◽  
The Relationship ◽  
Machined Surfaces

Understanding and anticipating the effects of surface roughness on subsurface stress in the design phase can help ensure that performance and life requirements are satisfied. The specific approach taken in this work to address the goal of improved surface design is to relate surface characteristics of real, machined surfaces to subsurface stress fields for dry contact. This was done by digitizing machined surfaces, simulating point contact numerically, calculating the corresponding subsurface stress field, and then relating stress results back to the surface. The relationship between surface characteristics and subsurface stress is evaluated using several different approaches including analyses of trends identified through stress field visualization and extraction of statistical data. One such approach revealed a sharp transition between cases in which surface characteristics dominated the stress field and those in which bulk, or global contact effects dominated the stress. This transition point was found to be a function of the contact operating conditions, material properties, and most interestingly, the roughness of the surface.

A Numerical Simulation of Fretting Wear considering the Dynamic Evolution of Debris for the Coated Contact Surface

2021 ◽  
pp. 1-49
Author(s):  
Li Xiao ◽  
Yingqiang Xu ◽  
Zhiyong Chen
Keyword(s):  
Fretting Wear ◽  
Contact Pair ◽  
Dynamic Evolution ◽  
Wear Depth ◽  
Wear Coefficient ◽  
Wear Model ◽  
Wear Process ◽  
Dlc Coating ◽  
Wear Life ◽  
Wear Calculation

Abstract In this paper, a multi-layer body model in which material properties and wear coefficient change with node coordinates is proposed, so that the wear profile is not restricted by the singularity of the interface of the coated contact pairs. The conversion rate of the adhered particles was obtained to describe the growth and expansion of the debris at the fretting interface based on experiments, and the wear model of coated contact pair considering the dynamic evolution of the debris layer was established. By comparing the previous experimental and computational results, the wear calculation method proposed in this paper is more reasonable to predict the wear profile of the coated contact pair. In addition, the influence of the debris layer on the wear depth, friction width, and contact pressure in the fretting process is analyzed, indicating that the existence of the debris layer can delay the wear process. Finally, the fretting wear life of the SCMV steel contact pair deposited with the W-DLC coating is estimated.

Electron Mobility due to Surface Roughness Scattering in Depleted GaAs Free-Standing Thin Ribbon

2019 ◽  
Vol 954 ◽  
pp. 51-59
Author(s):  
Xi Duo Hu ◽  
Cheng Ming Li ◽  
Shao Yan Yang
Keyword(s):  
Surface Roughness ◽  
Quantum Well ◽  
Electron Mobility ◽  
Atomic Scale ◽  
Free Standing ◽  
Poisson Equations ◽  
Surface Roughness Scattering ◽  
Calculation Results ◽  
Roughness Amplitude ◽  
Dimensional Electron Gas

Abstract:Electron mobility limited by surface roughness scattering in free-standing GaAs thin ribbon with an internal parabolic quantum well caused by surface state is investigated in detail. Based on analyzing the parabolic quantum well including the energy subband level, wave function and the confined potential profile in the thin ribbon by solving Schrödinger and Poisson equations self-consistently, the electron mobility could be investigated. Conclusion indicates that remote surface roughness (RSR) of the thin ribbon will change the two dimensional electron gas (2DEG) mobility through the medium of barrier height fluctuation of the parabolic well in atomic scale. Calculation results reveal that the 2DEG mobility decreases with increasing roughness amplitude, which is characterized in terms of the surface roughness height and the roughness lateral size.

scholarly journals A note on the effect of surface topography on adhesion of hard elastic rough bodies with low surface energy

2019 ◽  
Vol 28 (1) ◽  
pp. 8-12 ◽  
Author(s):  
Guido Violano ◽  
Giuseppe Demelio ◽  
Luciano Afferrante
Keyword(s):  
Surface Roughness ◽  
Surface Energy ◽  
Adhesive Contact ◽  
Low Surface Energy ◽  
Surface Gradient ◽  
Self Consistent ◽  
Remarkable Result ◽  
Roughness Amplitude ◽  
Adhesive Interactions ◽  
Effect Of Surface

AbstractAdhesion between bodies is strongly influenced by surface roughness. In this note, we try to clarify how the statistical properties of the contacting surfaces affect the adhesion under the assumption of long-range adhesive interactions.Specifically, we show that the adhesive interactions are influenced only by the roughness amplitude hrms, while the rms surface gradient h0rmsonly affects the non-adhesive contact force. This is a remarkable result if one takes into account the intrinsic difficulty in defining $h_{\mathrm{rms}}^{^{\prime }}.$Results are also corroborated by a comparison with self-consistent numerical calculations.

scholarly journals Rolling Contact Fatigue Life of Case−Hardened Steel Treated by Shot Peenings with Shot Diameters of 0.05 mm and 0.30 mm

2011 ◽  
Vol 86 ◽  
pp. 645-648 ◽  
Author(s):  
Lei Wang ◽  
Guang Liang Liu ◽  
Masanori Seki ◽  
Masahiro Fujii ◽  
Qian Li
Keyword(s):  
Surface Roughness ◽  
Fatigue Life ◽  
Shot Peening ◽  
Fine Particle ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Surface Hardness ◽  
Hardened Steel ◽  
Rolling Contact ◽  
Contact Fatigue Life

In order to investigate the influence of different shot peenings on the rolling contact fatigue life of case−hardened steel, the thrust type rolling contact fatigue test was performed with a ball−on−disk contact tester. In this study, the case−hardened steel disks were treated by the fine particle peening with a shot diameter of 0.05 mm and the normal shot peening with a shot diameter of 0.30 mm. The surface hardness and the surface compressive residual stress of the test disks were increased by these peenings. On the other hand, the surface roughness of the test disks was increased by the normal shot peening, and was decreased by the fine particle peening. The rolling contact fatigue test showed that the rolling contact fatigue life of the test disks was improved by the fine particle peening, and was not improved by the normal shot peening. The rolling contact fatigue life of the test disks became longer as their surface roughness became smaller. Therefore, it follows from this that the fine particle peening, which can provide the increase in surface hardness and the decrease in surface roughness, is good for the increase in the rolling contact fatigue life of case−hardened steel.

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