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Fatigue life prediction of rear axle using time series model
Yimin SHAO,Jieping FANG,Liang Ge,Jiafu OU,Hao JU,Ying MA 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10
The rear axle is one of the key parts of the automobile, lots failure of rear axle resulted from fatigue failure of the spiral bevel gears. A new method is proposed to solve the problem of accurately predicting the fatigue life of spiral bevel gears in rear axle. The method uses the recurrence tracing and difference method to improve the Autoregressive Moving Average (ARMA) model prediction accuracy, which uses variables determined from on-line measurements to characterize the state of the deterioration rear axle. The experimental results show the proposed method has relatively high prediction accuracy.
Efficiency Analysis of Planetary Gear Train under Ring Gear Deformation
Shao Yimin,Li Xuzhong,Li Hongwu,Chen Yan,Xu Jin 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10
Transmission efficiency is a key parameter of planetary gear train, it has a significant effect on power density of transmission systems. Usually, ring gear is regard as a rigid part in the efficiency calculation of planetary gear train. However, most of the planetary gear train adopt flexible ring gear design, which means the deformation of ring gear is large. In addition, the deformation of the ring gear leads to the change of the meshing relationship of the gears in the planetary gear train, thus both the dynamic load, sliding speed and friction force in the planetary gear train are affected. Besides, the meshing power loss in planetary gear train is also changed. Therefore, this paper takes the elastic deformation of the flexible ring gear and the dynamic friction force along the contact path of the gear teeth into consideration. Then the vibration responses of the planetary gear train are calculated based on a new established concentrated mass dynamic model. Next, power loss on the meshing interface and the meshing efficiency of the planetary gear trains are evaluated with the consideration of ring gear deformation. The calculation results show that the elastic deformation of the ring gear has a great influence on the meshing efficiency of the planetary gear train.
Simulation of Spur Gear pair with Faults Using FEA
Yimin SHAO,ZaiGang CHEN,Sheming Wang 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
A shock vibration is produced due to the sudden change of meshing stiffness of gears when some faults happen to the gears. The fault signals of the gears are always covered by the noises existing in the surroundings, especially under the strong noise background, which makes it difficult to extract the feature signals of fault accurately.In the field testing, to calculate the meshing stiffness and its change precisely is impossible. So the relationship betweenthe vibration and the meshing stiffness is hard to obtain. In order to solve this problem, the method of finite elementanalysis (FEA) is utilized in this paper to simulate the vibration of a spur gear pair with local fault and calculate the change of meshing stiffness. As a result, the relationships between the vibration of gears and the meshing stiffness are obtained.
Yimin Shao,Xiao Deng,Yilin Yuan,Chris K. Mechefske,Zaigang Chen 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.6
Detecting chatter mark vibration in rolling mills operating under normal working conditions is difficult. A novel characteristic recognitionmethod of chatter mark vibration, where the non-dimensional parameters are calculated with time varying signals and kurtosis undernormal rolling mill operating conditions, is presented in this paper. The character of the chatter mark vibration signal is obtained by calculatingthe kurtosis value of each vibration signal segment obtained by subdividing the raw time varying vibration signal. The probabilitydensity function is utilized to reveal obvious differences between signals with respect to the normal and chatter conditions. Themethod overcomes the limitation of traditional spectrum analysis, which is sensitive to working conditions. Numerical simulation andexperimental results show that the proposed method has better recognition capability than traditional spectrum analysis.
Fault Diagnosis System Based on Smart Bearing
Yimin SHAO,Liang GE,Jieping FANG 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10
According to statistics, a lot of the rotating machinery faults are caused by the bearings, so the smart bearing technique is important for ensuring safety of them. For the smart bearing, a representative definition is that sensing devices of the different use are integrated into the traditional bearing in order to realize self-diagnosis. For condition of the variable speed, variable load and heavy load, the diagnostic technology cannot satisfy requirement of the fault feature extraction at present. This paper presents a new smart bearing of the multi-parameters including of two vibration acceleration sensing devices, two speed sensing devices, and two temperature sensing devices. In addition, the heavy noise can be decreased for extraction of the weak fault signals by the embedded integrated mode of bearing and sensor.
A Simulation Study of Defects in a Rolling Element Bearing using FEA
Yimin SHAO,Wenbing Tu,Fengshou GU 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10
An internal impact usually happens when there is a small defect in one part of rolling bearings. The Fault signal from this impact is always masked by different noises such as strong vibrations from other parts and the random noise of instrumentation, which makes it difficult to extract an accurate feature signal for early fault diagnosis. In this paper, a simulation study is conducted using the method of finite element analysis (FEA) to understand the vibration characteristics from the small impact. The vibration responses have been modelled based on a typical bearing assembly. Common faults including outer ring defect, inner ring defect and rolling ball defect are simulated and their vibration responses are compared between different faults and at different locations in the bearing housing. The results obtained have shown that under the same defect size, the vibration from the outer ring is the highest whereas that from the rolling ball is the smallest. In addition the vibration close to the mounting hole attenuates considerably compared to that close to outer ring. These findings provide fundamental information to place vibration sensors and to analyse vibration signals.
A new method of spectral analysis -- synchronous cycle-ratio spectral analysis
Junqing Fu,Yimin Shao 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
A synchronous cycle-ratio analysis is presented in the paper. The new method considers 2π as a basic cycle, which embodies the characteristics of 2π cycle in rotating machinery. The new method overcame the shortcomings of order analysis. An experiment verified that the new method is very effective, which can excellently filter random noise by statistically synchronous averaging of samples, and the cycle-ratio leakage can be eliminated perfectly. The peak values of synchronous cycle-ratio spectrum is not only clear without noise and leakage, but can be used to identify therelated physical parameters, which will be very useful for trouble shooting of rotating machinery.
Hanjun Jiang,Yimin Shao,Chris K. Mechefske,Xiaohui Chen 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.11
Due to either elastic deformations or errors in the manufacturing or assembling of gears, shafts, bearings and their housings, it is an inevitableconsequence that mesh misalignment between teeth occurs. The change in length of the contact line or the change in load distributionalong the length of the contact line induced by mesh misalignment causes changes in the dynamic characteristics of helical gears. There is currently no satisfactory solution for the modeling and calculation of the internal excitation in helical gears with mesh misalignmentand sliding friction that would reveal the changes in the dynamic characteristics. In this study, an improved calculation method offriction excitation is proposed based on the time-varying length of the contact line and the time-varying friction coefficient model in helicalgears. By considering the change in the mesh position and the change in the length of the contact line or the change of the displacementerror along the contact line induced by mesh misalignment, the time-varying sliding friction force and the dynamic mesh force maybe obtained. An eight degree-of-freedom analytical helical gear pair model is developed by incorporating the time-varying sliding frictionforce and dynamic mesh force and considering the mesh misalignment. By assuming a constant mesh stiffness density along the contactline, the rules governing the variation of the dynamic response are obtained using simulations of helical gear pair examples with differentfriction coefficient models and mesh misalignment. The developed analytical model provides a new method for the study of excitationcharacteristics in helical gears with mesh misalignment.
Luyang Guan,Yimin Shao,Fengshou Gu,Bruno Fazenda,Andrew Ball 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
In this paper, a new method is proposed by combining ensemble empirical mode decomposition (EEMD) with order tracking techniques to analyse the vibration signals from a two stage helical gearbox. The method improves EEMD results in that it overcomes the potential deficiencies and achieves better order spectrum representation for fault diagnosis. Based on the analysis, a diagnostic feature is designed based on the order spectra of extracted IFMs for detection and separation of gearbox faults. Experimental results show this feature is sensitive to different fault severities and robust to the influences from operating conditions and remote sensor locations.