Improving the tribological characteristics of piston ring assembly in automotive engines using Al2O3 and TiO2 nanomaterials as nano-lubricant additives

Surface texturing has been frequently used for tribological purposes in the last three decades due to its great potential to reduce friction and wear. Although biological systems advocate the use of hierarchical, multi-scale surface textures, most of the published experimental and numerical works have mainly addressed effects induced by single-scale surface textures. Therefore, it can be assumed that the potential of multi-scale surface texturing to further optimize friction and wear is underexplored. The aim of this review article is to shed some light on the current knowledge in the field of multi-scale surface textures applied to tribological systems from an experimental and numerical point of view. Initially, fabrication techniques with their respective advantages and disadvantages regarding the ability to create multi-scale surface textures are summarized. Afterwards, the existing state-of-the-art regarding experimental work performed to explore the potential, as well as the underlying effects of multi-scale textures under dry and lubricated conditions, is presented. Subsequently, numerical approaches to predict the behavior of multi-scale surface texturing under lubricated conditions are elucidated. Finally, the existing knowledge and hypotheses about the underlying driven mechanisms responsible for the improved tribological performance of multi-scale textures are summarized, and future trends in this research direction are emphasized.

https://www.mdpi.com/2075-4442/7/11/95/pdf

Multi-Scale Surface Texturing in Tribology—Current Knowledge and Future Perspectives

Hydraulic seals are complicated machine elements. The engineering research on hydraulic reciprocating seals, which commenced roughly in the 1930s, has achieved a basic understanding of performance issues. This article provides a review of the experimental and theoretical research conducted over a period of eight decades, discussing more than 200 of the most significant publications from the related literature. The topics discussed include reciprocating seal designs, materials, experimental methods, theoretical studies, elastohydrodynamic lubrication, solid and contact mechanics, performance issues, and optimization.

Eighty years of research on hydraulic reciprocating seals: Review of tribological studies and related topics since the 1930s

Passenger car disc brakes are safety-critical components whose performance depends strongly on contact conditions at the pad-to-rotor interface. The interface can be classified as a conformal dry s ...

Simulation of wear and contact pressure distribution at the pad-to-rotor interface in a disc brake using general purpose finite element analysis software

Simulation of journal bearing friction in severe mixed lubrication – Validation and effect of surface smoothing due to running-in

Thermal elastohydrodynamic simulation of involute spur gears incorporating mixed friction

The influence of oil supply and cylinder liner temperature on friction, wear and scuffing behavior of piston ring cylinder liner contacts – A new model test

Simulation von Tribosystemen

Transient thermal elastohydrodynamic simulation of a DLC coated helical gear pair considering limiting shear stress behavior of the lubricant

This paper presents an elegant way to compute hydrodynamic lubrication in machine parts, especially in highly deformable dynamic seals. In such tribologic systems, the sealing and frictional behaviour is highly related to the interaction between the hydrodynamic lubrication and the structural deformation of the seal. In this work, a hydrodynamic interface element is developed in order to achieve a strong coupling of the fluid dynamics and the deformation of the solid structure. The fluid flow is represented by the two-dimensional steady-state Reynolds equation, the structural deformation by standard finite-element procedures. This method enables the application of arbitrary, non-linear material models provided by finite-element programs. Furthermore, a model for mixed lubrication, including frictional effects, is presented.

Dirk Bartel

Papers

Thermal elastohydrodynamic simulation of involute spur gears incorporating mixed friction

The influence of oil supply and cylinder liner temperature on friction, wear and scuffing behavior of piston ring cylinder liner contacts – A new model test

Simulation von Tribosystemen

Transient thermal elastohydrodynamic simulation of a DLC coated helical gear pair considering limiting shear stress behavior of the lubricant

An axisymmetric hydrodynamic interface element for finite-element computations of mixed lubrication in rubber seals