Modeling Tangential Contact of Rough Surfaces With Elastic- and Plastic-Deformed Asperities

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Dong Wang ◽  
Chao Xu ◽  
Qiang Wan
Keyword(s):  
Rough Surface ◽  
Normal Load ◽  
Experimental Results ◽  
Partial Slip ◽  
Tangential Load ◽  
Stick Slip ◽  
Normal Contact ◽  
Tangential Contact ◽  
Bilinear Relation ◽  
Proposed Model

A new tangential contact model between a rough surface and a smooth rigid flat is proposed in this paper. The model considers the contribution of both elastically deformed asperities and plastically deformed asperities to the total tangential load of rough surface. The method combining the Mindlin partial slip solution with the Hertz solution is used to model the contact formulation of elastically deformed asperities, and for the plastically deformed asperities, the solution combining the fully plastic theory of normal contact with the bilinear relation between the tangential load and deformation developed by Fujimoto is implemented. The total tangential contact load is obtained by Greenwood and Williamson statistical analysis procedure. The proposed model is first compared to the model considering only elastically deformed asperities, and the effect of mean separation and plasticity index on the relationship between the tangential load and deformation is also investigated. It is shown that the present model can be used to describe the stick–slip behavior of the rough surface, and it is a more realistic-based model for the tangential rough contact. A comparison with published experimental results is also made. The proposed model agrees very well with the experimental results when the normal load is small, and shows an error when the normal load is large.

scholarly journals Linear relationship of normal and tangential contact stiffness with load

2020 ◽  
Vol 476 (2243) ◽  
pp. 20200329
Author(s):  
K. S. Parel ◽  
R. J. Paynter ◽  
D. Nowell
Keyword(s):  
Surface Roughness ◽  
Linear Relationship ◽  
Normal Load ◽  
Contact Stiffness ◽  
Roughness Parameter ◽  
Image Correlation ◽  
Tangential Load ◽  
Normal Contact ◽  
Tangential Contact ◽  
Normal Contact Stiffness

Measurements with digital image correlation of normal and tangential contact stiffness for ground Ti-6Al-4V interfaces suggest a linear relationship between normal contact stiffness and normal load and a linear relationship between tangential contact stiffness and tangential load. The normal contact stiffness is observed approximately to be inversely proportional to an equivalent surface roughness parameter, defined for two surfaces in contact. The ratio of the tangential contact stiffness to the normal contact stiffness at the start of tangential loading is seen to be given approximately by the Mindlin ratio. A simple empirical model is proposed to estimate both the normal and tangential contact stiffness at different loads for a ground Ti-6Al-4V interface, on the basis of the equivalent surface roughness and the coefficient of friction.

Effects of Frequency on the Fretting Conditions in a Contact Between PMMA and a Rigid Counterface

1998 ◽  
Vol 120 (4) ◽  
pp. 729-736 ◽  
Author(s):  
A. Krichen ◽  
M. Kharrat ◽  
A. Chateauminois
Keyword(s):  
Numerical Simulations ◽  
Experimental Analysis ◽  
Dynamic Modulus ◽  
Normal Load ◽  
Displacement Amplitude ◽  
Partial Slip ◽  
Tangential Load ◽  
Stick Slip ◽  
Slip Conditions

The effects of frequency on the fretting conditions in a glass/PMMA contact have been investigated using experimental analysis and numerical simulations. For partial slip conditions, the changes in the shape of the fretting cycles giving the tangential load as a function of the imposed displacement have been interpreted on the basis of changes in the dynamic modulus of the PMMA as a function of frequency. Using the numerical simulations, the values of the PMMA’s modulus at the various frequencies were determined from the analysis of the fretting cycles. For gross slip conditions, the emphasis was placed on the determination of the range of velocity associated with stick-slip processes. This information has been summarized in a fretting map giving the initial fretting condition as a function of normal load, displacement amplitude, and frequency.

Modeling tangential contact based on non-Gaussian rough surfaces

2018 ◽  
Vol 233 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Wanglong Zhan ◽  
Ping Huang
Keyword(s):  
Rough Surfaces ◽  
Load Capacity ◽  
Experimental Results ◽  
Practical Significance ◽  
Partial Slip ◽  
Stick Slip ◽  
Tangential Contact ◽  
Tangential Stiffness ◽  
Negative Skewness ◽  
Non Gaussian

A stick-slip tangential contact model between rough surfaces was proposed in this paper. The Mindlin partial slip solution for elastic contact and the double linear formulation developed by Fujimoto for plastic contact in conjunction with the Coulomb dry friction law were used to derive tangential contact formulas. Pearson system of frequency curves was used to generate non-Gaussian random surfaces. Effects of skewness and kurtosis on normal and tangential contact responses were studied independently. The results showed that negative skewness predicted lower mean separation for a given normal force and greater tangential stiffness, while for positive skewness, there exist different trends from negative skewness. With the increase of kurtosis, the load capacity and tangential stiffness decreased. The practical significance of these findings is that it can help engineers to design proper surface textures based on their requirements. A comparison of initial tangential stiffness between predicted results and published experimental results was made. The results well agreed with the experimental results when the non-Gaussian surface effects were taken into consideration.

Nanoscale Friction Dynamic Modeling

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Fakhreddine Landolsi ◽  
Fathi H. Ghorbel ◽  
Jun Lou ◽  
Hao Lu ◽  
Yuekai Sun
Keyword(s):  
Friction Model ◽  
Experimental Results ◽  
Atomic Scale ◽  
Model Parameters ◽  
Large Set ◽  
Asperity Contact ◽  
State Variables ◽  
Stick Slip ◽  
Proposed Model ◽  
Nanoscale Friction

Friction and system models are fundamentally coupled. In fact, the success of models in predicting experimental results depends highly on the modeling of friction. This is true at the atomic scale where the nanoscale friction depends on a large set of parameters. This paper presents a novel nanoscale friction model based on the bristle interpretation of single asperity contact. This interpretation is adopted after a review of dynamic friction models representing stick-slip motion in macrotribology literature. The proposed model uses state variables and introduces a generalized bristle deflection. Jumping mechanisms are implemented in order to take into account the instantaneous jumps observed during 2D stick-slip phenomena. The model is dynamic and Lipchitz, which makes it suitable for future control implementation. Friction force microscope scans of a muscovite mica sample were conducted in order to determine numerical values of the different model parameters. The simulated and experimental results are then compared in order to show the efficacy of the proposed model.

Wear Prediction in Wheel-Rail Contact under Partial Slip Conditions

2014 ◽  
Vol 658 ◽  
pp. 317-322 ◽  
Author(s):  
George Gavrila ◽  
Spiridon Cretu ◽  
Marcelin Benchea
Keyword(s):  
Numerical Model ◽  
Normal Force ◽  
Rolling Contact ◽  
Experimental Results ◽  
Partial Slip ◽  
Initial Condition ◽  
Dynamic Effects ◽  
Stick Slip ◽  
Slip Conditions ◽  
Slip Phenomenon

This paper presents a numerical model to calculate wear during rolling contact due to micro-slip. Having as initial condition a corrugated rail it is shown the influence of the corrugation wavelength and the dynamic effects of the normal force on the wear creation. Experimental results are presented in order to reveal the influence of roughness when studying the stick-slip phenomenon.

Plane Contact and Partial Slip Behaviors of Elastic Layers With Randomly Rough Surfaces

2015 ◽  
Vol 82 (9) ◽  
Author(s):  
Fan Jin ◽  
Qiang Wan ◽  
Xu Guo
Keyword(s):  
Rough Surface ◽  
Contact Area ◽  
Elastic Layer ◽  
Partial Slip ◽  
Real Contact Area ◽  
Rigid Base ◽  
Slip Model ◽  
Normal Contact ◽  
Real Contact ◽  
Plane Contact

A plane contact and partial slip model of an elastic layer with randomly rough surface were established by combining the Greenwood–Williamson (GW) rough contact model and the Cattaneo–Mindlin partial slip model. The rough surface of the elastic layer bonded to a rigid base is modeled as an ensemble of noninteracting asperities with identical radius of curvature and Gaussian-distributed heights. By employing the Hertzian solution and the Cattaneo–Mindlin solution to each individual asperity of the rough surface, we derive the total normal force, the real contact area, and the total tangential force for the rough surface, respectively, and then examine the normal contact and partial slip behaviors of the layer. An effective Coulomb coefficient is defined to account for interfacial friction properties. Furthermore, a typical stick–slip transition for the rough surface was also captured by distinguishing the stick and slip contacting asperities according to their respective indentation depths. Our analysis results show that an increasing layer thickness may result in a larger real contact area, a lower mean contact pressure, and a higher effective Coulomb coefficient.

scholarly journals Tangential Loading of General Three-Dimensional Contacts

1998 ◽  
Vol 65 (4) ◽  
pp. 998-1003 ◽  
Author(s):  
M. Ciavarella
Keyword(s):  
Pressure Distribution ◽  
Poisson’S Ratio ◽  
Normal Load ◽  
Complete Solution ◽  
Tangential Force ◽  
Three Dimensional ◽  
Poisson's Ratio ◽  
Partial Slip ◽  
Normal Contact ◽  
Slip Regime

A general three-dimensional contact, between elastically similar half-spaces, is considered. With a fixed normal load, we consider a pure relative tangential translation between the two bodies. We show that, for the case of negligible Poisson’s ratio, an exact solution is given by a single component of shearing traction, in the direction of loading. It is well known that, for full sliding conditions, the tangential force must be applied through the center of the pressure distribution. Instead, for a full stick case the tangential force must be applied through the center of the pressure distribution under a rigid flat indenter whose planform is the contact area of the problem under consideration. Finally, for finite friction a partial slip regime has to be introduced. It is shown that this problem corresponds to a difference between the actual normal contact problem, and a corrective problem corresponding to a lower load, but with same rotation of the actual normal indentation. Therefore for a pure translation to occur in the partial slip regime, the point of application of the tangential load must follow the center of the “difference” pressure. The latter also provides a complete solution of the partial slip problem. In particular, the general solution in quadrature is given for the axisymmetric case, where it is also possible to take into account of the effect of Poisson’s ratio, as shown in the Appendix.

Comparison of non-Hertzian modeling approaches for wheel–rail rolling contact mechanics in the switch panel of a railway turnout

2018 ◽  
Vol 233 (4) ◽  
pp. 466-476 ◽  
Author(s):  
Xiaochuan Ma ◽  
Ping Wang ◽  
Jingmang Xu ◽  
Rong Chen
Keyword(s):  
Contact Problems ◽  
Rolling Contact ◽  
Head Width ◽  
Stick Slip ◽  
Normal Contact ◽  
Tangential Contact ◽  
Modeling Approaches ◽  
Contrast Analysis ◽  
Slip Region ◽  
Contact Relation

Due to the complicated wheel–rail contact relation of railway turnouts, it is necessary to select a reasonable rolling contact model to simulate the vehicle–turnout dynamics and wheel–rail damages. This paper mainly aims to evaluate the calculation accuracy and efficiency of different non-Hertzian modeling approaches in solving normal and tangential wheel–rail contact problems of railway turnouts. Four different non-Hertzian approaches, namely CONTACT, Kik–Piotrowski, Ayasse–Chollet, and Sichani methods are compared and analyzed. The above four models are built considering the relative motion of stock/switch rails. A wheel profile called LMA contacting with stock/switch rails (head width 35 mm) of CN60-1100-1:18 turnouts is selected as the object of analysis. The normal contact problems are evaluated by the wheel–rail contact areas, shapes, and normal contact pressures. The assessment of tangential contact problems is based on the creep curves, tangential contact stresses, and distribution of the stick/slip region. In addition, a contrast analysis is performed on the calculation efficiencies of the four approaches. It is found that the normal and tangential contact results calculated based on the Sichani method coincide well with those obtained according to CONTACT, and the calculation efficiency is about 262 times that of CONTACT. The conclusions can provide some guidance to the selection of wheel–rail rolling contact approach in the simulation of vehicle–turnout dynamics and wheel–rail damages.

Axisymmetric partial slip contact of a functionally graded piezoelectric coating under a conducting punch

2016 ◽  
Vol 28 (14) ◽  
pp. 1925-1940 ◽  
Author(s):  
Jie Su ◽  
Liao-Liang Ke ◽  
Yue-Sheng Wang
Keyword(s):  
Electric Charge ◽  
Contact Region ◽  
Functionally Graded ◽  
Partial Slip ◽  
Perfect Conductor ◽  
Stick Slip ◽  
Normal Contact ◽  
Functionally Graded Piezoelectric Materials ◽  
Slip Region ◽  
Functionally Graded Piezoelectric

This article considered the axisymmetric partial slip contact problem of a functionally graded piezoelectric coated half-space indented by a rigid spherical punch subjected to a normal load. It is assumed that the punch within the contact region is a perfect conductor with a constant electric potential. The electro-mechanical properties of the functionally graded piezoelectric materials vary exponentially along the thickness direction. The whole contact region consists of an inner circular stick region surrounded by an outer annular slip region obeying Coulomb’s law of friction. The problem is reduced to a set of coupled Cauchy singular integral equations by employing the Hankel integral transform. An iterative method is used to determine the unknown stick/slip region, normal contact pressure, electric charge, and radial tangential traction. The effects of the resultant electric charge, friction coefficient, and gradient index on the surface electro-mechanical fields are presented in detail.

Modelling of Mechanical Systems With Friction Interfaces Considering Variable Normal Contact Load and Tangential Micro/Macro Slip

2016 ◽  
Author(s):  
Dongwu Li ◽  
Chao Xu
Keyword(s):  
Normal Load ◽  
Friction Model ◽  
Hysteretic Model ◽  
Friction Contact ◽  
Restoring Force ◽  
Normal Contact ◽  
Load Variation ◽  
Proposed Model ◽  
Frictional Damping ◽  
Microslip Friction

Mechanical structures with frictionally constrained interfaces often involve complex contact kinematics induced by tangential and normal relative motions. The tangential motion induces stick-micro/macro slip friction and causes energy dissipation. The normal motion induces normal load variation and possible separation of the joint interfaces. For effective analysis of dynamics of jointed structures, a reduced friction contact model is needed to characterize the nonlinear, coupled normal and tangential contact behaviors precisely. However, most developed microslip friction contact models considers only constant normal load. In this paper, an improved microslip friction model with normal load variation induced by normal motion is proposed. The tangential stick-micro/macro slip friction is modeled by continuous Iwan hysteretic model. This model is characterized by a slippage uniform distribution density function and a linear stiffness at stick state. The coupling relationship between tangential nonlinear restoring force and normal load variation is built. This leads to generalization of the original Iwan hysteretic friction model to consider the effect of variable normal load. The proposed model is applied to model a 7-dofs frictional damping experimental system. The results show that normal load variation and tangential microslip motion exert an important effect on prediction of friction contact behaviors. The proposed model is capable of generating asymmetric hysteresis loops and intermittent normal separation. The numerical simulation fit well with the experimental results for the 7-dofs frictional damping system, which validates the effectiveness and accuracy of the proposed model.

Sign in / Sign up

Export Citation Format

Share Document