Effect of Third-Particle Material and Contact Mode on Tribology Contact Characteristics at Interface

Abstract

A moving pair with two-body contact is the ideal situation assumed in previous analyses. However, all moving pairs are in a three-body contact state at the start of operation or immediately after the start of operation, such as bearings, ball-screws, gears and engines. This work studies the influence of wear particles (SUJ2), environmental particles (SiO2 and Al2O3) and nano-additives (CuO) on the tribological contact characteristics under different particle concentrations, particle sizes, surface roughnesses and contact modes. The three-body microcontact analysis revealed that the differences in the real contact area, particle contact area and separation of the four-particle materials in the three-body s–s and p–s contact modes are rather small. Under the three-body hybrid contact mode, the difference is relatively large and the sequence of the real contact area value obtained due to the elastic modulus for the four-particle material at this interface is Al2O3 > SUJ2 > CuO > SiO2. The order of the other two contact characteristics is reversed. The difference increases as the particle size or particle concentration increases. The order of the critical load required to transform three kinds of contact modes is SiO2 > CuO > SUJ2 > Al2O3. On the nearly initial three-body hybrid contact mode, the plastic contact area ratio at the interface first increases to a critical value and then decreases as the load increases because the original plastic contact spot area and contact spot number increases with the increase in load. At the same time, the elasto-plastic contact area ratio decreases to a low value and then increases. The elastic contact area ratio at the interface decreases as the load increases. Among the four third-particle materials, the experimental results and theoretical predictions show that the environmental particles, Al2O3, cause the maximum friction and wear observed at the interface.

Investigation of lubricant viscosity and third-particle contribution to contact behavior in dry and lubricated three-body contact conditions

“…Various operating conditions influence TPCA in 3-body dry contact conditions (Chern et al, 2022). Various foreign particles influence the contact characteristics of 3-body dry contact interfaces and validate the feasibility of the theory through four-ball experiments (Horng et al, 2023). In recent years, although there have been studies on the effect of different lubricant viscosities on surface friction (Vanossi et al, 2020) and wear (Tsai, 2024), most studies have focused on 2-body contact conditions.…”

“…Under different conditions, the relationship between the three contact modes and the A sa,t * are observed (Horng et al, 2023), as shown in Figure 2. Figure 2A shows the surface-to-surface 3-body contact mode (s-s mode).…”

Nonmonotonic load‐dependence of friction during nanoparticle manipulation

“…Nanoparticles (NPs) have attracted considerable research interest due to their unique mechanical and chemical properties, particularly in the fields of nano-lubrication [1][2][3][4][5][6] and ultraprecision manufacturing [7][8][9][10][11][12]. Since the friction, wear, and energy loss between two mating surfaces of a friction couple are closely related to the motion state (sliding or rolling) of the third NPs [3,5,11], the comprehensive investigations into the tribological and dynamic behaviors of NPs motion have become essential.…”