滚动接触界面静态接触特性实验设计与教学实践

[Objective] As essential components that bear loads and rotate within high-end equipment, bearings are critical to determining the service life and operational reliability of these systems. However, wear failure caused by localized high contact stress at bearing assembly interfaces has become a technical challenge, impeding the evolution of high-end equipment toward greater precision and longevity. To tackle the core issue of performance degradation and lifespan constraints because of wear failure at bearing assembly interfaces, this study presents a novel optimization methodology for roller generatrix profiles utilizing the particle swarm optimization (PSO) algorithm. [Methods] The proposed optimization method focuses on the nodal contact stress differential between the roller contact edge and the symmetry axis as the objective function. The optimization variables include the shape parameters of HF-TK logarithmically modified rollers, which are adjusted logarithmically under a constant pressure of 2 kN, with curvature modification coefficient (k₁), logarithmic curve-to-contact length ratio (k₂), and terminal maximum crown value (Z_m) serving as optimization variables. Through an iterative optimization process using the PSO algorithm, the distribution of contact stress at the roller assembly interface is improved. Next, the optimized HF-TK logarithmically modified rollers are subjected to numerical analysis in comparison with three types of arc-shaped rollers and a straight generatrix roller. In addition, an experimental protocol is carefully designed and implemented for validation. A comparison of the numerical and experimental results delineated the fundamental mechanisms of roller profile geometry and assembly interface contact pressure distribution on stress distribution patterns. [Results] 1) The optimal shape parameters for the HF-TK logarithmically modified rollers are identified as k₁=2.4, k₂=1.0, and Z_m=0.018; 2) the contact area configurations of the straight generatrix and three arc-shaped rollers approximate rectangular shapes, exhibiting stress concentrations at both ends of the contact zone, with a slight widening of the contact width at these points; 3) for arc-shaped rollers, an inverse relationship exists between the percentage of the arc segment curve relative to the effective contact length of the roller generatrix and resultant contact length; 4) the optimized logarithmic curve roller features an elliptical contact area configuration, effectively mitigating stress concentrations at the edges of the contact zone, with maximum contact stress occurring in the center; 5) axial contact stress profiling along the roller axis indicates persistent edge stress concentrations in straight generatrix and arc-profile rollers. Among the three arc-profile variants, reduced contact lengths are associated with elevated stress concentration magnitudes. By contrast, the logarithmic curve roller, although exhibiting higher central contact stress, exhibits a smooth transition in stress gradients from the center to the periphery, entirely eliminating stress concentration phenomena. [Conclusions] By incorporating the PSO-based roller generatrix shape optimization methodology into educational frameworks, students can engage in the entire optimization design process, including the numerical analysis of bearing assembly interface wear failure, roller generatrix profile optimization, and experimental validation. This comprehensive involvement fosters a deep understanding of the interrelationships among curvature radius, load distribution, and assembly performance within contact theory. Furthermore, it enhances students' command of performance optimization methodologies for mechanical assembly interfaces while nurturing their engineering pragmatism and innovative capabilities.