A Numerical Study of the Contact Mechanics and Sub-Surface Stress Effects Experienced Over a Range of Machined Surface Coatings in Rough Surface Contacts

Kadiric, Amir; Sayles, R.S.; Zhou, Xiao Bo; Ιωαννίδης, Ε.

doi:10.1115/1.1574520

Cited by 30 publications

(23 citation statements)

References 18 publications

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“…20 However, a detailed analysis of ACL and its relation, if any, to friction behavior is lacking. Other recent works suggest that the correlation length affects subsurface stresses in coatings 21 as well as adhesion of thin elastic films. 22 The main objective of this paper is to analyze the effects of ACL on the real area of contact and on the adhesive friction force based on a peak analysis.…”

Section: Introductionmentioning

confidence: 99%

The effect of autocorrelation length on the real area of contact and friction behavior of rough surfaces

Zhang

Sundararajan

2005

Journal of Applied Physics

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Autocorrelation length (ACL) is a surface roughness parameter that provides spatial information of surfacetopography that is not included in amplitude parameters such as root-mean-square roughness. This paper presents a relationship between ACL and the friction behavior of a rough surface. The influence of ACL on the peak distribution of a profile is studied based on Whitehouse and Archard's classical analysis [Whitehouse and ArchardProc. R. Soc. London, Ser. A316, 97 (1970)] and their results are extended to compare profiles from different surfaces. The probability density function of peaks and the mean peak height of a profile are given as functions of its ACL. These results are used to estimate the number of contact points when a rough surface comes into contact with a flat surface, and it is shown that the larger the ACL of the rough surface, the less the number of contact points. Based on Hertzian contact mechanics, it is shown that the real area of contact increases with increasing of number of contact points. Since adhesivefriction force is proportional to the real area of contact, this suggests that the adhesivefriction behavior of a surface will be inversely proportional to its ACL. Results from microscale friction experiments on polished and etchedsiliconsurfaces are presented to verify the analysis. KeywordsFriction, Adhesion, Etching, Rough surfaces, Silicon, Atomic force microscopy, Surface measurements, Elasticity, Real functions, Topography DisciplinesMechanical Engineering | Nanoscience and Nanotechnology CommentsThe following article appeared in Journal of Applied Physics 97 (2005) Autocorrelation length ͑ACL͒ is a surface roughness parameter that provides spatial information of surface topography that is not included in amplitude parameters such as root-mean-square roughness. This paper presents a relationship between ACL and the friction behavior of a rough surface. The influence of ACL on the peak distribution of a profile is studied based on Whitehouse and Archard's classical analysis ͓Proc. R. Soc. London, Ser. A 316, 97 ͑1970͔͒ and their results are extended to compare profiles from different surfaces. The probability density function of peaks and the mean peak height of a profile are given as functions of its ACL. These results are used to estimate the number of contact points when a rough surface comes into contact with a flat surface, and it is shown that the larger the ACL of the rough surface, the less the number of contact points. Based on Hertzian contact mechanics, it is shown that the real area of contact increases with increasing of number of contact points. Since adhesive friction force is proportional to the real area of contact, this suggests that the adhesive friction behavior of a surface will be inversely proportional to its ACL. Results from microscale friction experiments on polished and etched silicon surfaces are presented to verify the analysis.

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Section: Introductionmentioning

confidence: 99%

The effect of autocorrelation length on the real area of contact and friction behavior of rough surfaces

Zhang

Sundararajan

2005

Journal of Applied Physics

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“…Many research efforts have investigated the effect of surface roughness on subsurface stress using numerical simulation [2][3][4][5][6][7][8][9]. Understanding this effect is particularly important for prediction of near-surface failure mechanisms such as spalling, pitting, or micro pitting [2,3,8].…”

Section: Introductionmentioning

confidence: 99%

Prediction of subsurface stress in elastic perfectly plastic rough components

et al. 2006

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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. One approach used to address this problem is to simulate contact between digitized real, machined surfaces, and then analyze the predicted subsurface stress field. Often, elastic-perfectly plastic contact models are used in these simulations because of their relative computational efficiency. Reported here is an analysis of the magnitude and location of maximum stress predicted using an elastic-perfectly plastic model. Trends are identified which then enable estimation of the upper bound of the simulation results based on surface discretization, operating conditions, and material properties. These estimations can be used as an effective and efficient tool for rapid prediction of maximum subsurface stress in real surface contact.

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“…In the presence of roughness, each asperity micro-contact creates a micro-stress field that is situated much nearer to the surface, and therefore there could be significant interactions of these shallower stress fields and any coating interfaces that happen to lie in the vicinity. This effect was studied by Kadiric and Sayles [25] for a single layered coating. To illustrate this in the current example, the four layered problem of the study above (Case 4 in Figure 9) is analysed again but now in presence of a roughness profile.…”

Section: Case Study On Optimising the Subsurface Stresses Through Coamentioning

confidence: 99%

Semi-analytical model for rough multilayered contacts

Nyqvist

Kadiric

Ioannides

et al. 2015

Tribology International

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This paper presents a new model for analysis of non-conformal rough surface contacts where one or both of the contacting bodies are coated with a multilayered coating. The model considers elastic contact of arbitrary geometry with real measured roughnesses and both normal and tangential surface loads. It predicts contact pressure distribution, surface deformations and full subsurface stress field. As such, the model offers an optimisation tool for analysis and development of multilayered coatings. Influence coefficients approach is utilised to obtain contact pressures and subsurface stresses while the contact solver is based on standard conjugate gradient method. To improve model efficiency, a semianalytical approach is devised, where the influence coefficients for displacements and stresses are expressed explicitly by solving the fundamental equations in the frequency domain. Fast Fourier Transforms in conjunction with discrete convolution are then utilised to provide the solution in spatial domain. Selected results are presented to first validate the model and then illustrate the potential improvements that can be achieved in the design of multilayered coatings through application of the model. A s -Influence coefficient matrix for general stress, SE* (1) -Equivalent elastic modulus based on properties of counter face and layer (1), 's parameters 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 4 1 Introduction Surface coatings are widely employed in tribological components with the primary aim of protecting contacting surfaces from damage and/or reducing friction, particularly under poor lubrication conditions. Bearings, piston rings, fuel injectors and cams and followers are some of the mechanical components were tribological coatings are often employed. Relative to a homogenous contact, presence of a coating in general modifies the contact mechanics in two ways: contact pressures and areas are either increased or decreased depending on the coating properties relative to the substrate and the subsurface stress fields are modified not least due to the mismatch in elastic properties of the coating and the substrate. When carefully controlled, such changes can offer superior contact performance but when poorly understood they can lead to premature failure of coated contacts through mechanisms that may not have been expected in the equivalent homogenous contact, such as fracture, fatigue and delamination. Many modern coatings possess a multilayered structure, where the properties of each coating layer can be chosen to optimise the prevalent contact mechanics for ...

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A Numerical Study of the Contact Mechanics and Sub-Surface Stress Effects Experienced Over a Range of Machined Surface Coatings in Rough Surface Contacts

Cited by 30 publications

References 18 publications

The effect of autocorrelation length on the real area of contact and friction behavior of rough surfaces

The effect of autocorrelation length on the real area of contact and friction behavior of rough surfaces

Prediction of subsurface stress in elastic perfectly plastic rough components

Semi-analytical model for rough multilayered contacts

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