Early Damage Detection in Planetary Gear Transmission in Down-Time Regime

The results of using early damage diagnostics technique (developed in the Mechanical Engineering Research Institute of the Russian Academy of Sciences (IMASH RAN) for detecting the latent damage of an aviation panel made of composite material upon bench tensile tests are presented. We have assessed the capabilities of the developed technique and software regarding damage detection at the early stage of panel loading in conditions of elastic strain of the material using brittle strain-sensitive coating and simultaneous crack detection in the coating with a high-speed video camera “Video-print” and acoustic emission system “A-Line 32D.” When revealing a subsurface defect (a notch of the middle stringer) of the aviation panel, the general concept of damage detection at the early stage of loading in conditions of elastic behavior of the material was also tested in the course of the experiment, as well as the software specially developed for cluster analysis and classification of detected location pulses along with the equipment and software for simultaneous recording of video data flows and arrays of acoustic emission (AE) data. Synchronous recording of video images and AE pulses ensured precise control of the cracking process in the brittle strain-sensitive coating (tensocoating)at all stages of the experiment, whereas the use of structural-phenomenological approach kept track of the main trends in damage accumulation at different structural levels and identify the sources of their origin when classifying recorded AE data arrays. The combined use of oxide tensocoatings and high-speed video recording synchronized with the AE control system, provide the possibility of definite determination of the subsurface defect, reveal the maximum principal strains in the area of crack formation, quantify them and identify the main sources of AE signals upon monitoring the state of the aviation panel under loading P = 90 kN, which is about 12% of the critical load.

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Dynamic characteristics analysis of planetary gear system with internal and external excitation under turbulent wind load

Science Progress ◽

10.1177/00368504211035604 ◽

2021 ◽

Vol 104 (3) ◽

pp. 003685042110356

Author(s):

Hexu Yang ◽

Xiaopeng Li ◽

Jinchi Xu ◽

Zemin Yang ◽

Renzhen Chen

Keyword(s):

Wind Speed ◽

Wind Turbine ◽

Nonlinear Dynamic ◽

Planetary Gear ◽

Wind Load ◽

Transmission System ◽

Gear Transmission ◽

Stiffness Ratio ◽

Gear Transmission System ◽

Planetary Gear System

According to the working characteristics of a 1.5 MW wind turbine planetary gear system under complex and random wind load, a two-parameter Weibull distribution model is used to describe the distribution of random wind speed, and the time-varying load caused by random wind speed is obtained. The nonlinear dynamic model of planetary gear transmission system is established by using the lumped parameter method, and the relative relations among various components are derived by using Lagrange method. Then, the relative relationship between the components is solved by Runge Kutta method. Considering the influence of random load and stiffness ratio on the planetary gear transmission system, the nonlinear dynamic response of cyclic load and random wind load on the transmission system is analyzed. The analysis results show that the variation of the stiffness ratio makes the planetary gear have abundant nonlinear dynamics behavior and the planetary gear can get rid of chaos and enter into stable periodic motion by changing the stiffness ratio properly on the premise of ensuring transmission efficiency. For the variable pitch wind turbine, the random change of external load increases the instability of the system.

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Device Concept for the Generation of Guided Waves for Early Damage Detection

Procedia Engineering ◽

10.1016/j.proeng.2012.09.363 ◽

2012 ◽

Vol 47 ◽

pp. 1185-1188 ◽

Cited By ~ 1

Author(s):

E. Köppe ◽

M. Bartholmai ◽

J. Prager

Keyword(s):

Damage Detection ◽

Guided Waves ◽

Early Damage

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Influence of the backlash generated by tooth accumulated wear on dynamic behavior of compound planetary gear set

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406215627831 ◽

2016 ◽

Vol 231 (11) ◽

pp. 2025-2041 ◽

Cited By ~ 4

Author(s):

Shijing Wu ◽

Haibo Zhang ◽

Xiaosun Wang ◽

Zeming Peng ◽

Kangkang Yang ◽

...

Keyword(s):

Dynamic Response ◽

Dynamic Model ◽

Dynamic Behavior ◽

Planetary Gear ◽

Tooth Wear ◽

Transmission Error ◽

Gear Transmission ◽

Tooth Surface ◽

Contact Ratio ◽

The Impact

Backlash is a key internal excitation on the dynamic response of planetary gear transmission. After the gear transmission running for a long time under load torque, due to tooth wear accumulation, the backlash between the tooth surface of two mating gears increases, which results in a larger and irregular backlash. However, the increasing backlash generated by tooth accumulated wear is generally neglected in lots of dynamics analysis for epicyclic gear trains. In order to investigate the impact of backlash generated by tooth accumulated wear on dynamic behavior of compound planetary gear set, in this work, first a static tooth surface wear prediction model is incorporated with a dynamic iteration methodology to get the increasing backlash generated by tooth accumulated wear for one pair of mating teeth under the condition that contact ratio equals to one. Then in order to introduce the tooth accumulated wear into dynamic model of compound planetary gear set, the backlash excitation generated by tooth accumulated wear for each meshing pair in compound planetary gear set is given under the condition that contact ratio equals to one and does not equal to one. Last, in order to investigate the impact of the increasing backlash generated by tooth accumulated wear on dynamic response of compound planetary gear set, a nonlinear lumped-parameter dynamic model of compound planetary gear set is employed to describe the dynamic relationships of gear transmission under the internal excitations generated by worn profile, meshing stiffness, transmission error, and backlash. The results indicate that the introduction of the increasing backlash generated by tooth accumulated wear makes a significant influence on the bifurcation and chaotic characteristics, dynamic response in time domain, and load sharing behavior of compound planetary gear set.

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