All downloads (19)

The simulation app for mixed-EHL rolling-sliding line contacts has been developed based on the capabilities of the Cam-Roller-Interface Tribotester (CRT-01). The CRT-01 as well as the simulation app, allow the user to evaluate the resulting slide-to-roll ratio (SRR) and traction coefficient (among others) generated in a lubricated roller on roller (i.e., disc on disc) configuration when a load torque is applied to the driven roller. Differently from classic twin disc machines, the CRT-01 allows the generation of slippage throughout the application of a load torque (i.e., braking torque) to one of the rollers. This means that slippage is not a fixed variable during the test but, a result of the applied braking torque. Hence, changes in the tractive behavior of surfaces produced by wear (or other factors) can be studied based on the variations of the SRR measured through the test. The interested user can refer to https://www.tribonet.org/news/testing-of-cam-roller-follower-systems/ and https://www.youtube.com/watch?v=LViW5rxueoM for more information about the testing method and the test setup.   Instructions for use: The mixed-EHL simulator for rolling sliding line contacts is divided into 3 different panels. The reference conditions, the controls, and the results. Reference Conditions: A set of reference conditions is given by default. They include contact conditions, material properties, and lubricant properties. The user can modify these values and click "Run" to display the results. Control Panel: The app allows the adjustment of 5 parameters for the simulation, namely, the load (L), the speed (ωR1), the temperature of the lubricant, the load torque, and the offset angle (Ψ). Note that with Ψ=0, the contact force is equal to the load (L). After adjusting the controls, the results can be obtained by clicking "Run". Results The results panel displays several results that can be used to evaluate the tribological behavior of the simulated contact. They include the lambda ratio, the traction coefficient, and the slide-to-roll ratio, among others. Note that the slide-to-roll ratio increases when higher load torques (i.e., braking torque) are applied.           Read More

On behalf of Professor George Adams. This is an overview of contact mechanics models in case of two spheres. The overview starts with Hertz model and continues to adhesive models and Greenwood-Williamson. A very good good summary for the case of two spheres.   Read More

Contact mechanics code useful for calculating subsurface stress

This thesis considers lubrication and wear in artificial joint replacements. The lubrication theory and model development is described in details and can be useful for anyone starting in the area of lubrication modeling.   Read More

'The correct lubricant' covers basic practical information about lubricants in automotive and industrial areas. It is written for users of lubricants, giving only what is essential to know and useful for them. It could also be used by professionals in the field who must explain various aspects of lubrication to their customers. And it is also designed as a textbook. 'The correct lubricant' is a practical book with very little chemistry, theory and calculations. It is up to date including details of the new diesel engine oil specifications.   The book will benefit anyone involved with the operation and maintenance of fleets and industrial plant and machinery in mining, manufacturing, construction, road works, trucking, transport and all other industries. There should be a hard copy of this book in every plant and fleet. A part of the package is a web page with more than 1500 links to relevant articles listed in line with the contents of the book.   Read More

This work demonstrates the importance of summit parameters for an anisotropic Gaussian rough surface. It is shown that lay direction may significantly affect the running-n wear process.   Read More

A script that solves the linear complementarity problem associated with the Boussinesq contact mechanics problem   h = K*p+g, h'*p=0, h,p >=0, where the unknown h is the gap between two elastic (half-space) bodies and the unknown p is the corresponding contact pressure. It can also be found at file exchange at the MATLAB Central   Read More

Matlab routines solving a linear complementarity problem appearing in lubrication with cavitation. Can also be found at the file exchange at MATLAB central.   Read More

Tribology Simulator is a software for the simulation of the most common tribological contact – a contact of two surfaces in a sliding motion. Besides the macro geometry surfaces can have microgeometry or nanogeometry (roughness). The contact may also be lubricated or dry. Examples of the problems that can be solved with Tribology Simulator: nominally smooth hydrodynamic simulation, nominally smooth and rough contact simulation (pressure and subsurface stress calculations, deflections), Stribeck Curve simulation (calculation of friction in mixed lubricated contacts), calculation of contact temperatures in solids, wear and wear particles simulation and surface roughness evolution, tribofilm generation. A manual can be found in the Help section. If you dont have MATLAB installed, you will need to install the MATLAB Compiler Runtime (MCR, free for download). See readme.txt file for further details. Solvers are based on the half-space approximation theory for the contact, thermal and hydrodynamic simulations, which makes it faster compared to Finite Element Method or other fully numerical approaches.   Read More

These m-files calculate the adhesive parameters of the contact between 2 spheres based on the mechanical and geometrical properties of these 2 bodies and show the pressure distribution in such a contact.   Read More

A Matlab code (GUI) for calculation of friction coefficient in mixed lubricated conditions. Asperity based, including statistical (Greenwood and Williamson), deterministic models. Fully elastic and elastic-plastic deformation regimes. Both point and line contact cases considered. Applicable to the contact with uniform film thickness (highly loaded). Moes fit is used to calculate central film thickness. Run stribeck_simulator.m.   Read More

The code plots the stress field along x direction due to a cuboid strain located in the center of coordinates system in an Infinite Space. The matlab file reproduces a plot from paper: "On the stress field due to initial strains in a cuboid Surrounded by an Inifinte Elastic Space", Chiu, 1977. It is useful in construction of 3D FFT based algorithm for calculation of elastic stress field due to initial strains (or residual, thermal, etc.).   Read More

A Matlab based line contact EHL solver with artificial diffusion for highly loaded cases. The degree of the diffusion is controlled. Fully coupled, differential deflection based numerical scheme. Finite difference discretization, central difference approximation of the pressure term and 2-nd order backward difference approximation of the wedge term. Roelands pressure-viscosity relation. It is designed for solving highly loaded cases. Newtons numerical solver is used. Launch run_numerical.m.   Read More

A Matlab based line contact EHL solver. Fully coupled, differential deflection based numerical scheme. Finite difference discretization, central difference approximation of the derivatives. Roelands pressure-viscosity relation. It is optimized for lightly deforming contacts. Newtons numerical solver is used. Fast to converge, accurate solution. Launch run_numerical.m.   Read More

A Matlab code for calculation of a semi-analytical solution of transient 1D Reynolds equation using Grubin's approximation. At first, the Reynolds equation is integrated analytically using Grubin's assumptions with respect to spatial coordinate and further numerically integrated with respect to temporal coordinate. Solution is then compared to the analytical Grubin’s solution for the central film thickness.   Read More

A Matlab code for calculation of a semi-analytical solution of transient 1D Reynolds equation for rigid-isoviscous case. At first, the Reynolds equation is integrated analytically with respect to spatial coordinate and further numerically integrated with respect to temporal coordinate. Solution is then compared to the analytical Martin’s solution for the central film thickness.   Read More

A Matlab file with the analytical solution of 1D Reynolds equation with possibility to specify the cavitation pressure. If cavitation pressure is set to atmosphere pressure, you get Martin’s solution. Derivation is also attached.   Read More

A simple matlab code for calculation of Hertz solution (Hertz model) for line, point and elliptical contacts. Also shows a plot of resultant pressure and deflection (not for elliptical contact)   Read More

Calculates central film thickness for line and point contacts using Moes fit.   Read More