基于响应面方法的轴承多应力加速模型建模与验证技术

针对轴承加速寿命试验中多应力加速模型欠缺、失效规律认识不到位等科学问题,首先,深入分析真空、温度、预紧力、转速、微重力环境下,液体润滑轴承的界面微观失效模式及机理;然后,推导和建立考虑上述多应力综合作用机理的微观接触统一润滑模型,研究给出基于改进牛顿-拉夫逊法的数值解算方法;其次,设计5因素5水平的正交仿真方案,开展真空、温度、预紧力、转速、微重力的失效规律仿真与分析,获得微观接触界面膜厚、压力峰值、摩擦系数、最大下表面应力随应力水平及接触区尺寸变化的失效响应值;最后,建立了基于响应面方法辨识真空、温度、预紧力、转速、微重力水平与失效响应值之间的多应力加速模型,并对其进行试验验证及工程应用,奠定了空间轴承加速寿命试验的模型基础.

Modeling and verification technology of bearing multi-stress acceleration model based on response surface method

This paper addresses the scientific problems in bearing accelerated life test, such as lack of multi-stress acceleration model, and not well understanding of failure law. Firstly, the interface micro failure mode and mechanism of fluid lubricated bearing under environment of vacuum, temperature, preload, speed and microgravity are analyzed. Secondly, the micro contact uniform lubrication model considering multi-stress comprehensive working mechanism is derivated and established, and the numerical solution method based on improved Newton Raphson method is proposed. Thirdly, the orthogonal simulation scheme with 5 factors and 5 levels orthogonal table is designed, the bearing failure law in the work of vacuum, temperature, preload, speed and microgravity is simulated and analyzed, and the failure response value of micro contact surface film thickness, pressure peak, friction factor, maximum undersurface stress which changes with the stress level and contact region dimension is obtained. Finally, the multi-stress acceleration model about vacuum, temperature, preload, speed and microgravity based on response surface method has been established, which is verified by a test of actual engineering example.