Papers by Author: Xiao Yang Chen

Abstract: An elastic contact solution considering the effect of free surface and code are developed using Hetenyi’s approach and semi-analytical method. Discrete convolution-fast Fourier transform (DC-FFT) is used to calculate elastic deformation. The modified conjugate gradient method is applied to solve surface contact pressure. By comparing with other literatures’ results, the program made by authors is proved valid.

Abstract: In this paper, the EHL oil film thickness and shape between a needle roller and a flat rectangular glass in pure rolling oscillated working conditions had been measured based on optical interferometry. The EHL behavior affected by the applied load, oscillating frequency was investigated. The typical film shape varies of interference pictures on the maximum needle roller rotation velocity was obtained and compared each other. It is found the side constrictions are always the most severe and they are strongly speeds and loads dependence.

Abstract: Commercial vehicle clutch release bearings working at high speed, strong vibration,high temperature, damp and easy pollution conditions. Fatigue life analysis is based on the release bearing rings or rolling body began to appear fatigue spalling, in which this kind of phenomenon is under cyclic stress. The contact stress distribution is not uniform, the contact stress is mainly concentrated near the surface; influenced by the geometry and physical properties and lubrication of the surface significantly. Contact between the two types of fatigue crack extension methods: fatigue crack surface under expansion and surface fatigue crack propagation. The surface crack growth mainly originated from two kinds of cases: crack caused by surface pre crack and contact between the two surface asperity each other. New life prediction model for the release bearing based on L-P theory and Tallian model ,in which influence factors of fatigue life is introduced on the smelting process, surface defect, surface roughness, residual stress, elastohydrodynamic lubrication oil film,environmental cleanliness, temperature, the effect of varying load characteristics and other factors of fatigue life. The results show that: the clutch release bearing life prediction model of new and more close to the real conditions of automobile clutch, provide the theory basis for the development of a new generation high-speed heavy-duty clutch release bearing of the commercial vehicle.

Abstract: This paper is focused on the finite element analysis (FEA) and theoretical calculation of vibration characterization of V-shaped electrothermal microactuator. A vibration mechanical model about V-shaped electrothermal microactuator is presented. By having a comparison between FEA and theoretical calculation about natural frequencies of V-shaped electrothermal microactuator, the maximum error is within 0.19 %. This paper also analyzes the influences of microactuator geometric parameters on natural frequency. The length and thickness have larger effect on the natural frequency of the actuator, while the angle and width have less effect on the natural frequency.

Abstract: Clutch release bearings are an important vehicle powertrain components. Web-based collaborative design automotive clutch release bearings, making the regional formation of enterprises dynamic virtual design team, through a combination of scattered in various technological advantage, the talent to play all engineers, technicians can not subject to geographical restrictions, by computer supported collaborative design (CSCD), is a collaborative model of human and computer technology convergence of new technologies. By numerical calculation and the C^# language on the separation of the axial load bearing capacity of the design process is developed. It is established on separate static analysis of the proposed bearing model.

Abstract: This article describes the clutch release bearings research on the separation of research methods and characteristics of the bearings described in detail. the off-road vehicle Clutch release bearings often speed, strong vibration, high temperature, humid workability pollution conditions work require release bearings good strength and toughness, resistant to impact wear and excellent contact fatigue performance. Release bearing vibration characteristics and on life affect important theoretical significance and socioeconomic value.

Abstract: It is presented to apply the designing methodology in design of an accelerated pure rolling contact fatigue test rig for ceramic bearing ball. Starting with function analysis, the request and structure of test rig are analysed. Meanwhile, the form matrix table is established, from which many designing schemes can be obtained. In accordance with several kinds of innovation schemes, the appraised decision of product is analyzed. The specimen machine is made according to the design scheme in the design of innovation.

Abstract: An intelligent control system for ceramics ball rolling contact fatigue test rig based on LabVIEW was designed. The system consists of four functional blocks, which are data acquisition block, signal processing block, state recognition block and diagnosis decision-making block. The data in the test process such as load, vibration, speed, fatigue life and so on, are collected and recorded automatically. This system can alarm or shutdown once the test rig state is abnormal or the truncate time is satisfied. By using wavelet transform and other methods in the vibration signal processing and analysis, the failure parts can be detected accurately according to the spectral characteristics and the fault characteristic frequency of the parts. The intelligent control system has practical advantages. The high precision, fast response, low cost, accurate judgment and convenience manipulation are very desirable for ceramics ball rolling contact fatigue experiment.

Abstract: By using a new type pure rolling fatigue test rig with three contact points for silicon nitride bearing ball specimen, the contact deflection angle of specimen with three contact points is calculated. The effects of the center height and test ball radius on the specimen contact deflection angle are analyzed. The analysis indicates that the span of contact deflection angle is 0-0.181° while the center height is 1.2mm and the design radius is 6.35mm and the specimen radiuses change from 4mm to 8mm. The more contact deflection angle is, the more variation rang of test ball radius is. The contact deflection angle can be less than 0.2° while the center height is optimized. The contact deflection angle has a direct influence on the stress error of the specimen. It is less than 1% while the contact deflection angle is less than 0.2°. The research provides a theoretical basis for optimization of test rig structure size and increase of specimen’s extension and improvement of test precision.

Abstract: It is important to build the models for calculating the cutting-forces in high-speed machining, but it is difficult as the special test-bed with the cutting-force measurement system is complicated, cost much and cannot be applied directly on general machining tools. Aiming at the problems above, a new method was put forward about cutting-force modeling based on the current of high-speed electric spindles, in which the cutting-force models could be gained indirectly by analyzing the built-in motor current and the data gotten from cutting experiments on those general machining tools which are installed with electric spindles. Then on a vertical milling machine tool which is equipped with a high-speed electric spindle, a model for calculating the milling force was gotten using the method put forward by this paper. The results show that the method is simple and easy to be used in routine machine tools in plant spots and need no any special test-beds and any complicated measurement systems possessed only in the laboratory conditions.