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Dynamic analysis of three-dimensional helical geared rotor system with geometric eccentricity
Yimin Zhang,Qibin Wang,Hui Ma,Jing Huang,Chunyu Zhao 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.11
A dynamic model of a multi-shaft helical geared rotor system is presented. Rotating shafts of the system are modeled as Timoshenko beams. A general three-dimensional dynamic model of helical gear pairs with geometric eccentricity is developed for the gear mesh and bearing flexibility is included in the model as well. The transmission error and gear geometric eccentricity are simulated as excitations. Eigenvalue solution and the modal summation technique are used to predict the natural frequencies and forced responses of the system. Then two geared rotor system models are presented for validation of the gear dynamic model. It is demonstrated that the gear mesh model is effective for general geared rotor systems, spur and helical gears, one-stage and multi-stage systems. Finally, forced responses of an example system are analyzed to demonstrate the influences of the helical gear geometric eccentricity and the coupling between gear geometric eccentricity and rotor mass unbalance.
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.
Reliability-based sensitivity of mechanical components with arbitrary distribution parameters
Yimin Zhang,Xiangdong He,Zhou Yang,Qiaoling Liu,Bangchun Wen 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.6
This paper presents a reliability-based sensitivity method for mechanical components with arbitrary distribution parameters. Techniques from the perturbation method, the Edgeworth series, the reliability-based design theory, and the sensitivity analysis approach were employed directly to calculate the reliability-based sensitivity of mechanical components on the condition that the first four moments of the original random variables are known. The reliability-based sensitivity information of the mechanical components can be accurately and quickly obtained using a practical computer program. The effects of the design parameters on the reliability of mechanical components were studied. The method presented in this paper provides the theoretic basis for the reliability-based design of mechanical components.
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.
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 XIE,Hong WU,Yanming LAI 한국펄프·종이공학회 1999 한국펄프종이학회 기타 간행물 Vol.- No.-
A new process for deinking of colored offset newsprint, i.e. enzyme treatment in cooperation with ultrasonic wave was developed in the present study. The physical characteristics such as fiber length, coarseness, crystallinity index of the de inked pulps were investigated and the sugar residues released from the treatment were analyzed. It was found that colored offset newsprint could be deinked effectively by cellulase treatment when ultrasonic wave was applied. The brightness increased by 5%ISO over that of control experiment and the pigment content was reduced markedly. Though the ultrasonic wave had little effect on the strength and crystallinity of the pulp, the treatment of enzyme combined with ultrasonic wave reduced the coarseness and fiber length to some extent. It was also found that ultrasonic wave could accelerate the hydrolysis of cellulose and hemicellulose during the cellulase treatment.