Search

• A highly efficient method for evaluating the risk of tooth contact fatigue failure is proposed, taking into account the effects of surface topography, residual stress, and hardness gradient. • The correlation between the specific distribution of residual stress, hardness gradient and the risk of tooth contact fatigue failure has been identified, laying a theoretical foundation for the anti fatigue design of tooth surfaces. • The combined effect of residual stress and hardness gradient on tooth contact fatigue failure was determined, and its underlying mechanisms were elucidated. • The anti fatigue optimization design standards for detailed parameters of residual stress and hardness gradient are provided, providing guidance for the anti fatigue design of high-performance gears. Residual stress and hardness gradient significantly affect the contact fatigue failure process of rough tooth surfaces, and the meticulous design of their characteristic parameters can help improve the fatigue resistance of gears. In this paper, an efficient computational method for rough tooth surface contact is established based on the reconstruction modeling of asperities and mixed lubrication analysis. By comprehensively considering the effects of residual stress and hardness gradient, the Dangvan multiaxial fatigue criterion is adopted to predict and analyze the contact fatigue life of the gear surface. The correlation between the surface residual stress, maximum residual stress depth, surface hardness, and effective hardening layer depth, among other characteristic parameters, and the contact fatigue performance of tooth surfaces is established. The results show that: (1) Increasing the magnitude of surface residual compressive stress and surface hardness can significantly reduce the risk of fatigue failure in the near-surface layer of the gear. To achieve the same fatigue performance, there is a linear negative correlation between the design values of the two parameters. (2) Affected by the double stress peaks in the rough tooth surface stress field, the maximum residual stress depth significantly affects the depth at which the highest failure risk occurs. With changes in roughness, the optimal design value of the maximum residual compressive stress depth changes from about 0.5 times the Hertzian contact half-width depth in the subsurface layer ( Sa < 0.2 μm) to about 15 μm in the near-surface layer ( Sa > 0.4 μm). (3) Considering both process cost and gear surface fatigue resistance, the design threshold for the effective hardening layer depth should be greater than the Hertzian contact half-width. This paper establishes a composite correlation between the meticulous characteristic parameters of residual stress, hardness gradient, and the contact fatigue performance of tooth surfaces, providing theoretical support for optimal design of tooth surface anti-fatigue performance. [ABSTRACT FROM AUTHOR]

• The cause of fatigue failure in steel wire rope suspenders on suspension bridges has been identified. • The recommended approach of utilizing auxiliary cables is successful in decreasing tensile-bending fatigue stress levels. • These discoveries are significant for guiding the development and upkeep of comparable infrastructure ventures. In consideration of the significant impact of train loads on the fatigue of suspenders in railway bridges, this paper focuses on the first railway suspension bridge in China − the Jinsha River Railway Suspension Bridge. The study analyzes the force characteristics and bending failure features of the steel wire ropes in railway suspension bridges, aiming to provide insights into the design of such structures. Firstly, a finite element model of the Jinsha River Railway Suspension Bridge is established in this paper. The natural frequencies are analyzed and compared with on-site measurements to validate the accuracy of the finite element model. Secondly, the tension force amplitude and angular displacement amplitude of the suspenders are analyzed under design loads, and the failure characteristics of the cables are experimentally examined. Subsequently, a wear fatigue test for steel wire rope is designed, evaluating the fatigue life of the suspender in the bridge. The computational results are compared with experimental data to validate their accuracy. Finally, structural measures to reduce the bending fatigue of railway suspension bridge suspenders are proposed to ensure their safety during the service life. The study reveals that the presence of bending stress exacerbates the fatigue failure of suspension cables in railway suspension bridges, with the failure mode identified as fatigue failure due to the tension-bending-wear coupling effect. Furthermore, our findings indicate that the implementation of auxiliary cables can reduce the displacement differential at both ends of the suspension cables by approximately 4/5, and decrease the axial tensile stress amplitude by about 3/4. Consequently, this significantly enhances the fatigue life of the suspension cables. [ABSTRACT FROM AUTHOR]

This paper introduces a method for predicting the fatigue life of single crystals, which fuses image data and physical data by exploiting machine learning techniques. The proposed approach establishes a comprehensive study by progressively contributing a new database to the field, enabling the inference of service conditions, including temperature and σ max , as well as inherent material properties from fracture images, such as crystal orientation. We evaluate the effectiveness of the proposed method via its application to the fatigue life prediction of DD6 alloy, which achieves promising performance across various crystal orientations. The extensive experimental analysis and evaluation suggest that our proposed method has high predictive accuracy and computational efficiency of our proposed method. These results show that our approach holds promise for enhancing our understanding of material fatigue and improving predictive precision in failure analysis. • Innovated dataset for fatigue life prediction. • Strengthened linkage of fracture surfaces to lifespans. • Visualized areas of CNN focus, aiding future work. • Integrated CNN with linear regression for notable results. [ABSTRACT FROM AUTHOR]

• The contact load between the roller and the raceway in the bearing is measured. • Proposing a life prediction method for the bearing under variable load conditions. • Bearings at different locations of one wheelset show different fatigue lives. In this paper, a life prediction method for axle box bearing rolling contact fatigue under wheel-rail excitation conditions is present. The dynamic contact load between the rollers and the outer raceway was considered the critical mechanical parameter for rolling contact fatigue of the bearing and measured based on strain detection of the bearing outer ring. In the bench test, the different excitation frequencies were simulated by a polygonal roller with varying rotation speeds. Then, the load spectrums of the measured loads were compiled and used as the input data for the life prediction model of rolling contact fatigue. Since the subsurface material element of the raceway is subject to the complex multiaxial stress state during service, the fatigue life was estimated based on the improved moment of the load path model. Besides, the linear damage accumulation rule was applied to evaluate the fatigue life of the bearings, considering the varying contact load that the outer raceway was subject to. Finally, the predicted fatigue lives of two double-row tapered roller bearings under different excitation conditions were present based on the proposed method. [ABSTRACT FROM AUTHOR]