Xinghui Han

Finite element analysis of fatigue life for deep groove ball bearing

The aim of this article is to develop an accurate three-dimensional finite element model of deep groove ball bearing to analyze fatigue lives for outer race and inner race. By the finite element analysis, the stress and strain datasets for outer race and inner race are obtained and used to calculate the fatigue lives. Based on a reliable fatigue criterion, the effect of various applied loads on the fatigue lives of outer race and inner race is investigated. Several parameters, namely the raceway groove curvature radii of outer race and inner race and the thicknesses of outer race and inner race are varied to investigate their effect on the fatigue lives. Research results provide useful guidelines for determining the design parameters.

Microstructure and Texture Evolution in Cold Rotary Forging of Spur Bevel Gears of 20CrMnTi Alloy Steel

The microstructure of cold rotary forged gears greatly affects their working life. Therefore, the aim of this study is to reveal the evolution of microstructure and texture that occurs during the cold rotary forging of spur bevel gears of 20CrMnTi alloy steel. The evolution of grains of the gear tooth is investigated through optical microscopy. By employing scanning electron microscopy and electron backscatter diffraction, the evolution of the cementite particles and the texture of the gear tooth is also revealed. The results indicate that the grain size distribution is non-uniform from the tooth profile to its center. The cementite particles in the tooth profile are finer and more uniformly distributed than those in the tooth center. After cold rotary forging, the tooth center has a combination of α- and γ-fibers, and the γ-fibers are more developed than the α-fibers, while most of the components in the tooth profile are assembled along the α-fibers.

Distribution of Microstructure and Vickers Hardness in Spur Bevel Gear Formed by Cold Rotary Forging

Cold rotary forging is a novel metal forming technology which is widely used to produce the high performance gears. Investigating the microstructure and mechanical property of cold rotary forged gears has a great significance in improving their service performance. In this study, the grain morphology in different regions of the spur bevel gear which is processed by cold rotary forging is presented. And the distribution regulars of the grain deformation and Vickers hardness in the transverse and axial sections of the gear tooth are studied experimentally. A three-dimensional rigid-plastic FE model is developed to simulate the cold rotary forging process of a spur bevel gear under the DEFORM-3D software environment. The variation of effective strain in the spur bevel gear has been investigated so as to explain the distribution regulars of the microstructure and Vickers hardness. The results of this research thoroughly reveal the inhomogeneous deformation mechanisms in cold rotary forging of spur bevel gears and provide valuable guidelines for improving the performance of cold rotary forged spur bevel gears.

Study on stress intensity factors for crack on involute spur gear tooth

Investigating the stress intensity factors has a great importance to predict the fatigue damage for the involute spur gears. The aim of this article is to reveal the variation laws of stress intensity factors for crack on the involute spur gear tooth. For this purpose, a three-dimensional finite element model for calculating the stress intensity factors of the involute spur gear containing a surface crack is established using the finite element code ABAQUS. Based on the established three-dimensional finite element model, the influences of several parameters, such as torque, friction coefficient, crack depth, crack initial location, and crack size, on mode I, mode II, and mode III stress intensity factors are investigated numerically. The results of the study provide valuable guidelines for enhanced understanding of stress intensity factors for the crack on the involute spur gear tooth.

Calculation Method for Rocking Die Motion Track in Cold Orbital Forging

In cold orbital forging, the rocking die performs complex motions on the components and the intervention between them cannot emerge, otherwise the components cannot be shaped successfully. Calculating the rocking die motion track is essential to determining whether there is intervention between the rocking die and components. Thus, this study aims to comprehensively investigate the rocking die motion track in cold orbital forging. For this purpose, an analytical model for calculating the rocking die motion track is first established. Then a universal motion track equation that can denote any geometry and kinematics relationships between the rocking die and components is obtained using this analytical model. To verify the validity of this motion track equation, an experimental study is conducted. The result shows that the calculated rocking die motion track is consistent with the experimental one. According to this valid motion track equation, the characteristics of the rocking die motion track are revealed. Finally, to apply the calculated rocking die motion track for analyzing the intervention between the rocking die and components, two case studies are examined.

Effect of equivalent feed amount per revolution on cold rotary forging process by 3D elastic–plastic dynamic explicit FE method

Abstract Cold rotary forging is an advanced and very complex incremental metal forming process with multifactor coupling interactive effects. Previous research is mainly based on experimental and analytical methods and thus cannot provide full details on the deformation characteristics and mechanisms of cold rotary forging. In the current work, a decisive factor in cold rotary forging, namely equivalent feed amount per revolution , is first determined, and its mathematical expression is presented. A reasonable three-dimensional elastic–plastic dynamic explicit finite element model of cold rotary forging of a cylindrical workpiece was established under the ABAQUS software environment. Through numerous simulation calculations and the analysis of equivalent plastic strain, it has been found that there are three plastic penetrating states of the cylindrical workpiece under different . On the basis of these plastic penetrating states, the effect laws of on the metal flow, degree of inhomogeneous deformation of workpiece and force and power parameters have been investigated, and thus, the deformation characteristics and mechanisms of cold rotary forging have been thoroughly revealed. The results show that with increasing , the ‘mushroom’ effect of the deformed cylindrical workpiece becomes less obvious and the deformation becomes more homogeneous, while the maximum axial forging force and forging moment gradually increase. Second, the effect of by changing the inclination angle γ of the upper die on the cold rotary forging process is different from that by changing the feed rate v of the lower die or the rotational speed n of the upper die.