Simulations in Tribology with TriboSolver: Understanding Contact Mechanics, Friction, and Wear

Introduction

Understanding friction, wear, and lubrication is essential for designing reliable mechanical systems. From bearings and gears to seals and microelectromechanical systems, the interaction between contacting surfaces influences performance, energy efficiency, and component lifespan. However, experimental measurements alone do not always reveal what happens at the microscopic level where many tribological processes begin.

To explore how simulation can address these challenges, TriboNet hosted the webinar “Simulations in Tribology with TriboSolver” on October 15, 2026. The session introduced TriboSolver Version 3, a simulation tool developed and used by the TriboNet team for more than a decade. The presenters explained the principles behind tribological modelling, introduced the Boundary Element Method (BEM), demonstrated the software’s desktop application, and discussed research applications and practical limitations.

The webinar featured presentations by Aydar Akhchurin, Xavier Borras, Manoj Rajankunte Mahadeshwara, including a live demonstration showing how to configure a simulation, run calculations, and interpret the results.

Why Are Simulations Important in Tribology?

Tribological experiments typically measure observable responses such as friction force, torque, and wear. Although these measurements are essential, they do not necessarily explain the physical mechanisms responsible for the observed behaviour.

For example, two rough surfaces may produce a particular friction coefficient, but the measurement alone cannot show exactly where the surfaces touch, how the contact pressure is distributed, or how much deformation occurs at individual asperities.

Simulations help researchers investigate these otherwise difficult-to-measure properties. By modelling the physics behind an experiment, they can estimate internal contact conditions and develop a more detailed understanding of tribological behaviour.

During the webinar, the presenters highlighted several advantages of simulation:

• Access to local contact information: Simulations can estimate contact pressure, real contact area, surface separation, deformation, and subsurface stresses.
• Faster investigation of operating conditions: Researchers can explore different loads, temperatures, and other parameters without physically testing every possible scenario.
• Multiscale analysis: Depending on the method, simulations can investigate phenomena ranging from nanoscale surface interactions to larger engineering components.
• Improved interpretation of experiments: Numerical results can help connect measured friction or wear to the physical mechanisms occurring at the interface.

Simulation does not replace experimental testing. Instead, combining modelling with measurements provides a more comprehensive understanding of how a tribological system behaves.

Understanding Lubrication Regimes and the Stribeck Curve

An important topic in the webinar was the relationship between surface contact, lubricant film formation, and friction. These interactions are commonly explained using the Stribeck curve, which describes how friction changes with lubrication conditions.

The presenters discussed three principal lubrication regimes: boundary, mixed, and full-film lubrication.

Boundary lubrication

In boundary lubrication, the lubricant film is insufficient to fully separate the contacting surfaces. A substantial proportion of the load is carried by the surface asperities, making solid contact and surface interactions important factors in friction and wear.

Understanding this regime requires information about the actual contact area and the local pressures developed between surface features.

Mixed lubrication

Mixed lubrication occurs when the load is shared between the lubricant film and the contacting asperities. The solid surfaces remain in contact at some locations, while the lubricant supports part of the load elsewhere.

This regime can be particularly challenging to model because both solid contact mechanics and fluid-film behaviour must be considered. The presenters explained that load-sharing concepts help connect these two contributions.

Full-film lubrication

In full-film lubrication, the lubricant supports the load sufficiently to separate the solid surfaces. Friction is then associated primarily with the shearing of the lubricant rather than direct contact between asperities.

Understanding the transitions between these regimes is important when investigating friction, especially in systems operating under changing loads or speeds.

For further background, TriboNet’s article on the Stribeck Curve and Boundary and Mixed Lubrication explains how these regimes relate to friction behaviour and operating conditions.

What Is the Boundary Element Method?

The Boundary Element Method was one of the central technical topics of the webinar. TriboSolver uses BEM-based and semi-analytical methods to solve contact mechanics problems efficiently.

Different simulation methods are appropriate for different physical scales and research objectives. Atomistic methods, such as density functional theory and molecular dynamics, investigate interactions at very small scales. Finite Element Analysis (FEA) is widely used in engineering to model complex geometries and material behaviour.

However, modelling rough surface contact using finite elements can become computationally expensive because the surface roughness and surrounding material volume may both need to be discretised.

BEM offers an alternative approach. Rather than discretising the entire body, it primarily discretises the contacting surface and uses analytical relationships derived from elasticity theory to calculate surface deformation.

The webinar explained how the method combines the contributions of forces acting across a surface to determine the resulting deformation and contact pressure. Fast Fourier Transform techniques can accelerate these calculations, making the method particularly useful for rough surface contact problems.

This approach can reduce computational demands while allowing researchers to investigate detailed surface topographies.

To explore the principles in more detail, readers can consult TriboNet’s tutorial on Contact Pressure for Rough Surfaces, which discusses BEM-based contact analysis and the calculation of real contact areas.

Introducing TriboSolver Version 3

TriboSolver is a tribology simulation application designed to investigate contact mechanics and related problems. During the webinar, the presenters introduced Version 3 and demonstrated its desktop interface.

The application brings several simulation capabilities together in one environment, allowing users to define contact conditions, specify material properties, configure surface geometry, run calculations, and analyse the resulting data.

The capabilities discussed during the session included:

• Direct contact analysis: Calculation of contact pressure, real contact area, surface gaps, and elastic or plastic deformation.
• Subsurface stress analysis: Investigation of stresses beneath contacting surfaces.
• Hydrodynamic calculations: Analysis of lubricant-film behaviour and related pressure and thickness distributions.
• Thermal analysis: Calculation of contact temperatures, subject to the model’s limitations.
• Wear-related simulations: Investigation of surface evolution associated with wear.
• Adhesion analysis: Modelling of effects such as van der Waals and electrostatic adhesion.
• Surface tools: Generation and analysis of surface topography.

These capabilities help researchers investigate different aspects of tribological behaviour without treating every contact problem as an entirely separate modelling exercise.

Readers interested in exploring the software can visit TriboNet’s TriboSolver Rough Contact Simulation Guide, which provides a practical introduction to setting up and analysing a rough contact calculation.

Research Applications: From Ice Friction to Electrostatic Adhesion

The webinar also presented examples of published research in which TriboSolver was used to investigate contact mechanics and support the interpretation of experimental observations.

1. Ice friction and capillary adhesion

The first example examined the relationship between surface roughness, humidity, and friction. Researchers investigated silicon nitride spheres with different surface roughness levels sliding against sapphire.

The study combined atomic force microscopy (AFM) topography measurements, friction testing, contact imaging, and numerical simulations.

The research explored how small water bridges can form between closely spaced surfaces under humid conditions, producing capillary adhesion. This mechanism can help explain why smoother surfaces may exhibit higher friction in particular conditions.

According to the webinar presentation, the smoothest surface had approximately four times the real contact area of the comparison surfaces, while the friction coefficient varied by nearly 20%.

TriboSolver’s role was to calculate contact patches and local gaps using an elasto-plastic boundary element model. These results helped connect measured surface geometry with the proposed physical explanation for the observed friction behaviour.

2. Running-in and the evolution of surface asperities

The second example focused on running-in, the initial period during which contacting surfaces change as they slide against one another.

At the beginning of sliding, a small number of prominent asperities may carry concentrated loads. As these features wear or deform, the contact conditions change, influencing the distribution of pressure, the real contact area, and friction.

The researchers combined surface measurements and microscopy with numerical modelling to investigate these changes.

As reported during the webinar, the calculated real contact area increased from approximately 13 to 55.6 square micrometres after a sliding distance of around 40 mm. The friction coefficient also decreased from an initial peak of approximately 0.63 to 0.31.

TriboSolver helped calculate pressure distributions, real contact areas, and plastic deformation based on measured surface topography. These calculations supported the interpretation of how changes in individual asperities affected the overall contact.

This example demonstrates how simulation can help explain the connection between surface evolution and changes in friction during running-in.

3. Electrostatic adhesion and surface roughness

The third example investigated electrostatic adhesion between a polysilicon ball and a silicon wafer.

The study examined how surface roughness influences the electric field and adhesion at the interface. Small gaps surrounding surface asperities can concentrate electric fields, meaning that local separation distances may be important when estimating electrical interactions.

The researchers used elastic boundary element calculations to resolve the deformed interface, identify solid contact patches, and estimate the geometry of the surrounding nanoscale gaps.

The webinar highlighted an important finding: positive voltage increased adhesion and friction, whereas negative voltage had comparatively little effect under the reported conditions. The associated modelling indicated that local attractive pressures could approach 100 MPa within a microscale contact footprint at voltages below 30 V.

TriboSolver provided contact-mechanics information that could be used by a separate electrical model to investigate local electric fields and attractive forces.

Together, these three examples illustrate how contact simulation can support research into phenomena that extend beyond conventional friction and wear measurements.

Live Demonstration: Setting Up a Contact Simulation

A practical highlight of the webinar was the demonstration of TriboSolver’s desktop application.

The presenter walked through the process of setting up a direct contact simulation, showing how users can define the physical properties and geometry of a contact before calculating its response.

The main steps included:

1. Selecting the simulation type. The user chooses the relevant model, such as direct contact analysis.
2. Defining material properties. Inputs include the elastic modulus, Poisson’s ratio, and hardness of the contacting bodies. Coating properties and thickness can also be specified for supported analyses.
3. Setting contact conditions. The applied load, boundary conditions, and relevant friction settings are defined.
4. Configuring the numerical grid. Users specify the physical simulation area and grid resolution.
5. Defining the contact geometry. Available configurations include point contact, line contact, and flat-on-flat contact.
6. Importing or generating surface roughness. Measured topography can be imported using supported file formats, including CSV data, or surface roughness can be generated when measured data are unavailable.
7. Running and analysing the calculation. The software produces results that can be plotted, examined through cross-sections, and exported or compiled into reports.

The demonstration showed how roughness can significantly affect the pressure distribution compared with an idealised smooth contact. Users can examine outputs such as contact pressure, elastic displacement, plastic deformation, gaps between surfaces, and contact area maps.

These visualisations provide a way to connect numerical results with the physical geometry of the contacting surfaces.

What Are TriboSolver’s Current Limitations?

The webinar also addressed questions about the software’s current capabilities, helping clarify which problems it can and cannot solve directly.

Wear rate calculation: TriboSolver can investigate surface evolution associated with wear, but the presenters clarified that calculating the wear rate itself must currently be performed using other tools.

Thermal effects of coatings: Coatings can be included in supported mechanical analyses, including subsurface stress calculations. However, the presenters stated that the current thermal calculation does not account for the coating’s thermal influence in the way asked about during the session.

Complex geometries in mixed lubrication: The mixed lubrication solver is suited to supported contact geometries, such as spherical and cylindrical contacts. More complex geometries may not be directly supported for film-thickness calculations. For dry or boundary contact analysis, custom surface geometry can be considered through supported imports.

Nonlinear material behaviour: The presenters clarified that the software includes certain extended contact models, including an elastic-ideally plastic model in which contact pressure is limited by a specified hardness. This should not be interpreted as support for every form of nonlinear or viscoelastic material behaviour.

These distinctions are important when choosing a simulation tool. Users should check whether a particular model’s assumptions match their research question and whether additional calculations or experimental validation are required.

How to Access TriboSolver

At the end of the webinar, the presenters explained how interested users could obtain access to the software.

According to the session, TriboSolver is available free of charge to academic users who apply using their university email address. Other users can explore the available personal or commercial licensing options through the software website. Attendees were also offered a 15-day trial, as described during the webinar.

Visit TriboNet’s TriboSolver Resource Page for software information and downloads, and consult the Rough Contact Simulation Tutorial for guidance on setting up a calculation.

The presenters also welcomed feedback, suggestions, and reports of potential software issues. They discussed possible future developments, including an elastohydrodynamic lubrication (EHL) solver, additional analytical and surface-analysis tools, and the possibility of expanding online access.

Conclusion

The TriboNet webinar Simulations in Tribology with TriboSolver demonstrated how numerical modelling can provide insights into the local mechanisms governing friction, wear, lubrication, and adhesion.

By combining boundary element methods with practical simulation tools, TriboSolver enables users to investigate rough surface contact, calculate contact pressure and real contact area, explore deformation and subsurface stresses, and support the interpretation of experimental results.

The research examples involving ice friction, running-in, and electrostatic adhesion illustrated how detailed contact information can help explain complex physical behaviour that is difficult to identify from global measurements alone.

The session also highlighted the importance of understanding model limitations and combining simulation with experimental evidence. For researchers, students, and engineers working in tribology, TriboSolver offers a practical way to explore contact mechanics and investigate how surface geometry and operating conditions influence tribological performance.

To learn more, explore the TriboSolver Tutorials and Resources on TriboNet and discover how simulation can support your next tribology research or engineering project.