Pitting Damage Levels Estimation for Planetary Gear Sets Based on Model Simulation and Grey Relational Analysis

Abstract

The planetary gearbox is a critical mechanism in helicopter transmission systems. Tooth failures in planetary gear sets will cause great risk to helicopter operations. A gear pitting damage level estimation methodology has been devised in this paper by integrating a physical model for simulation signal generation, a three-step statistic algorithm for feature selection and damage level estimation for grey relational analysis. The proposed method was calibrated firstly with fault seeded test data and then validated with the data of other tests from a planetary gear set. The estimation results of test data coincide with the actual test records, showing the effectiveness and accuracy of the method in providing a novel way to model based methods and feature selection and weighting methods for more accurate health monitoring and condition prediction.Keywords: planetary gear sets; pitting damage; feature selection; grey relational analysis; damage level estimation. TITRE FRANÇAIS DE L'ARTICLE (MAXIMUM DEUX LIGNES) RÉSUMÉLe résumé français est obligatoire. Évidement, si l'article est rédigé en français, le titre principal et le résumé principal sont en français. Par contre, il ne faut pas traduire le texte « Received…Accession Number 0000 ».Mots-clés : premier mot-clé; deuxième mot-clé; troisième mot-clé. INTRODUCTIONThe majority of mishaps in helicopters are caused by engine and drive train failures. To reduce these mechanically induced failures and excessive maintenance, it is vital to accurately identify and diagnose developing faults in the mechanical system. Planetary gear sets are common mechanical components and are widely used to transmit power and change speed and/or direction in rotary aircrafts. One of the most common causes of planetary gear sets failure is tooth defect due to excessive stress conditions. It results in progressive damage to gear teeth and ultimately leads to the complete failure of the planetary gear sets. This fault is particularly challenging as it is located deep inside the main transmission, suggesting it would be difficult to detect earlier.

Symmetry breaking and chaos-induced imbalance in planetary gears

“…When the planetary gearbox operates under some inappropriate conditions, such as inadequate lubrication, poor specifications, material defects and improper manufacturing or installation, it is likely to cause gear teeth faults. Once the tooth faults appear, the dynamic performances of the gearbox are bound to be affected, with undesirable changes in the dynamic behavior and serious reduction in the service life of the planetary system [30][31][32][33]. Recently, Gu and Velex developed a dynamic model including three-dimensional effects and errors [34,35], and Li et al [36] proposed a deep investigation on chaotic effects in planetary gears.…”

Analysis of Time-Varying Mesh Stiffness and Dynamic Response of Gear Transmission System with Pitting and Cracking Coupling Faults

“…Bilal El Yousfi [24] double-discretized the tooth surface to consider the variation of defect depth in the width and length direction of the gear teeth, and proposed a method to calculate meshing stiffness of spur gears based on potential energy. Cheng et al [25] proposed a rectangular pitting model and put forward a method to evaluate the degree of pitting damage. Chen et al [26] regarded the pitting pit as cylindrical.…”

Fault Feature Analysis of Gear Tooth Spalling Based on Dynamic Simulation and Experiments

“…When the gear spalling fault occurs, the reduction of gear contact length is the main reason for the change of TMS and dynamic response [13]. Simplifying spalling fault as a rectangular or circle shape, Cheng et al [14], Abouelseoud et al [15], and Saxena et al [16] analytically studied the effects of a single pit or spalling on the TMS. Liang et al [17] investigated the influences of multiple spalling on the TMS, and the spalling was modeled as a circle shape.…”

“…According to the above, the research on tooth spalling gradually led to more attention. Although some works [11][12][13][14][15][16][17][18] have been done on TMS of gear teeth with spalling or pitting, the research on vibration characteristics caused by spalling faults is still relatively few. In addition, although the bearing system is a key part of gear systems, the bearing was usually simplified to a simple spring system [1][2][3][4][5][6][7][8]19]; few references consider an accurate modeling of bearings.…”