Effects of lubrication on gear performance: A review

Study on gear contact fatigue failure competition mechanism considering tooth wear evolution

A study of effects of tooth surface wear on time-varying mesh stiffness of external spur gear considering wear evolution process

Ratchetting–multiaxial fatigue damage analysis in gear rolling contact considering tooth surface roughness

Digital Twin-Driven Remaining Useful Life Prediction for Gear Performance Degradation: A Review

With the mounting application of carburized or case-hardening gears and higher requirements of heavy-load, high-speed in mechanical systems such as wind turbines, helicopters, ships, etc., contact fatigue issues of gears are becoming more preponderant. Recently, significant improvements have been made on the gear manufacturing process to control subsurface-initiated failures, hence, gear surface-initiated damages, such as micropitting, should be given more attention. The diversity of the influence factors, including gear materials, surface topographies, lubrication properties, working conditions, etc., are necessary to be taken into account when analyzing gear micropitting behaviors. Although remarkable developments in micropitting studies have been achieved recently by many researchers and engineers on both theoretical and experimental fields, large amounts of investigations are yet to be further launched to thoroughly understand the micropitting mechanism. This work reviews recent relevant studies on the micropitting of steel gears, especially the competitive phenomenon that occurs among several contact fatigue failure modes when considering gear tooth surface wear evolution. Meanwhile, the corresponding recent research results about gear micropitting issues obtained by the authors are also displayed for more detailed explanations.

https://www.mdpi.com/2079-6412/9/1/42/pdf

A Review on Micropitting Studies of Steel Gears

Micropitting is a typical surface contact fatigue in rolling–sliding contact. The kinematic sliding is of great significance in the initiation and progression of micropitting. A numerical surface fatigue model considering rolling–sliding contact and surface evolution is developed based on mixed-EHL (elastohydrodynamic lubrication) theory, rainflow cycle counting method and Archard’s law. Surface evolution is evaluated using Archard’s wear law based on measured teeth surface topography. Surface damage is determined via the Palmgren–Miner line rule and Goodman diagrams. The effect of rolling speed and surface roughness are discussed in detail. Results show that stress micro-cycles are introduced by rough sliding in the rolling–sliding contact. The mild wear reduces the height of asperities, the maximum pressure and alleviates subsurface stress concentration. For rolling–sliding contact, the faster moving surface dominates the composite height of asperities, then decides the fluctuations of pressure, as well as stress ranges. The combination of surface topography should be considered in the surface design.

A Micropitting Study Considering Rough Sliding and Mild Wear

Study on gear bending fatigue considering gradient characteristics: Numerical analysis and experiments

Analytical study of tooth flank fracture in case-hardened gears considering non-metallic inclusion

Surface initiated rolling contact fatigue (RCF) of gears and rolling bearings can lead to premature failure in mechanical transmission systems. The orientation of surface crack initiation closely depends on surface tractive force, while the mechanism leading to this dependence is still obscure. In this work, a numerical model is proposed to investigate the effect of friction on surface crack initiation in RCF. An inhomogeneous contact solver based on semi-analytical method (SAM) is developed by combining the damaged-coupled constitutive relation and the Eshelby's equivalent inclusion method. The damage accumulation and concurrent degradation of material properties are modeled with continuum damage mechanics (CDM). The effect of surface tractive force on the orientation of surface crack initiation is simulated and analyzed. Results indicate that the progressive evolution of damage under the cyclic loading is accompanied by the stress variation around the damaged area. The damaged area increases, and the crack initiation life decreases with an increasing coefficient of friction. 

Ye Zhou

Papers

A Review on Micropitting Studies of Steel Gears

A Micropitting Study Considering Rough Sliding and Mild Wear

Study on gear bending fatigue considering gradient characteristics: Numerical analysis and experiments

Analytical study of tooth flank fracture in case-hardened gears considering non-metallic inclusion

The effect of friction on surface crack initiation in rolling contact fatigue considering damage accumulation