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Analysis of high-speed angular ball bearing lubrication based on bi-directional fluid-solid coupling

Jiao Bowen, Bian Qiang, Wang Xinghong, Chunjiang Zhao, Chen Ming, Zhang Xiangyun

Archive of Mechanical Engineering

2023

LXX, nr 4

531--551

The lubrication of angular contact ball bearings under high-speed motion con- ditions is particularly important to the working performance of rolling bearings. Combining the contact characteristics of fluid domain and solid domain, a lubrication calculation model for angular contact ball bearings is established based on the RNG 𝑘-𝜀 method. The pressure and velocity characteristics of the bearing basin under the conditions of rotational speed, number of balls and lubricant parameters are analyzed, and the lubrication conditions and dynamics of the angular contact ball bearings under different working conditions are obtained. The results show that the lubricant film pressure will rise with increasing speed and viscosity of the lubricant. The number of balls affects the pressure and velocity distribution of the flow field inside the bearing but has a small effect on the values of the characteristic parameters of the bearing flow field. The established CFD model provides a new approach to study the effect of fluid flow on bearing performance in angular contact ball bearings.

Effect of material microstructure on tool wear behavior during machining additively manufactured Ti6Al4V

Dang Jiaqiang, Cai Xiaojiang, Yu Dedong, An Qinglong, Ming Weiwei, Chen Ming

Archives of Civil and Mechanical Engineering

2020

Vol. 20, no. 1

41--55

Additive Manufacturing (AM) technologies are increasingly applied in various industries since they provide the possibility to manufacture the components with high geometrical complexity easier and faster than traditional processes. However, the subsequent semi-finish/finish machining operations such as drilling, turning and/or milling are still necessary for AM parts to obtain the required surface textures and meet the practical requirements. As such, the AM parts usually indicate different machinability compared with conventionally produced ones in view of the different material microstructures. A comprehensive understanding of this machining effort is of great importance for similar engineering applications but not widely reported. Thus, an attempt was made in this work to address the effect of the material microstructure on the machining stability and tool wear behavior in dry drilling of the hard titanium alloys. The experimental results highlight a correlation between the tool wear behavior and material microstructures. A great number of micro-pits appeared on the tool flank face and the abrasive marks, coating delamination, as well as catastrophic failure of the cutting edge were found to be more obvious during machining the DMLS alloy. In contrast, adhesion wear followed by micro chipping and build-up edge were distinguished when machining the wrought Ti6Al4V. Meanwhile, heat treatment can improve the flow plasticity and reduce the brittleness of the AM material since catastrophic failure disappeared and chip adhesion becomes more predominant when machining the HTDMLS Ti6Al4V.

Study on forward and inversion modeling of array laterolog logging in a horizontal/highly deviated well

Zhu Peng, Li Zhiqiang, Chen Ming, Dong Yixin

Acta Geophysica

2019

Vol. 67, no. 5

1307--1318

Electric feld synthesis was carried out using the multi-feld superposition method according to the working principle of the array laterolog electrode system. The feld distribution of each subfeld was simulated with the 3D finite element method, and the laterolog response of the array was obtained using the linear superposition principle of electric feld. The detection depth and thin layer response at diferent angles of the array laterolog were analyzed. The forward response calculation shows that the radial detection depth of the array laterolog is smaller than the deep laterolog detection depth. When the inclination angle of the well is less than 15°, the logging response of the array laterolog is less afected by the well inclination, and the well inclination correction need not be performed. The logging response values of highly deviated wells with inclination angles exceeding 60° and horizontal wells are quite diferent from those of vertical wells; thus, well deviation correction must be performed. To improve the stability of array laterolog logging inversion using the accurate forward response, a Newton–singular value decomposition method based on particle swarm optimization is proposed to realize inversion of array laterolog logging, and the stability and reliability of logging inversion are greatly improved. Thus, application of the theoretical model and actual data processing and analysis show that the proposed method can efectively and accurately eliminate the infuence of a complex logging environment and obtain real formation parameters.