滚动轴承复合故障振动建模及Lempel-Ziv复杂度评价

故障建模是探寻机械诊断中认知规律的关键环节。为了更能准确地预知振动特征,研究滚动轴承结合面间的多体接触与传递过程的耦合作用,根据Hertzian理论建立一种详细的计及内圈-外圈-轴承座传递过程的6DOF振动模型。从轴承实际运动学的角度刻画故障的形成及渐进发展过程,进而实现单点、复合故障的有效模拟,并与实验结果进行了比较。轴承运行过程中故障状态的变化,必然导致振动信号复杂性的变化。基于非线性动力系统理论,引入Lem-pel-Ziv复杂度指标评价运行状态。结果表明,单点及复合故障的信号具有不同的复杂度,反映了不同故障状态的动力学响应的差异。Lempel-Ziv复杂度能有效描述轴承振动信号的复杂性,可作为量化指标用于滚动轴承状态评价。

Vibration modeling of rolling bearings Considering Compound multi-Defects and appraisal with Lempel-Ziv complexity

The vibration modeling is a key link to explore the cognitive rules in fault diagnosis. In order to foresee the vibration characteristics accurately and efficiently, the transfer path and dynamic contact among joint interfaces are well studied. A novel methodology for dynamic modeling of 6DOF systems with bearing inner race-outer race- housing is presented based on the theories of Hertzian contact. The progressive processes of single and compound multi-defects are described by using practical kinematics of rolling bearings. The model provides the vibrations in time and frequency domains. Computed results from the model are validated with experimental results, which are generated using defective deep groove ball bearings. The complexities of vibration signal change with the emergence, and growth of faults. In this paper a new method of quantitatively describing the running condition of rolling bearings, based on nonlinear dynamics theory, is introduced. The Lempel-Ziv complexity measure is used to characterize the complexity of single and compound multi-defects signals. Results show that the complexity measure used as a quantitative criterion can effectively appraise the running condition of rolling bearings.