裂纹故障下的行星轮系唯象建模及其故障诊断

故障机制是故障诊断的基础,动态建模是研究故障机制的重要手段。现有的行星轮系动态建模主要包括动力学建模和唯象建模两方面。动力学建模难度大,且更多关注单个零部件的动力学特性;唯象建模则从宏观层面对系统特性进行描述。因此,建立行星轮系振动唯象模型,对行星轮系故障机制研究大有裨益。齿根裂纹是行星轮系中常见的故障类型之一。为此,建立了行星轮系正常与裂纹故障下的振动唯象模型,基于冲击动力学理论,计算了轮齿进入啮合时的啮合冲击力及其对动载因数的影响;在此基础上,建立了考虑啮合冲击影响的行星轮系振动唯象模型,得到了正常、太阳轮裂纹、行星轮裂纹等不同健康状态下的振动唯象模型响应;采用均方根、峭度等统计指标对模型响应进行分析,对比了各项统计指标在反映裂纹故障状态时的敏感性。结果表明,峭度可以作为有效反映行星轮系裂纹故障的指标之一。

Modeling of a Demethanizer Tower Using Statistical Tools

Monitoring of industrial plant performance and detection on flaws is important to the successful operation on industrial production units. Malfunctioning equipment can greatly impact plant performance by reducing the efficiency and increasing the production cost. Phenomenological equations cannot properly describe industrial processes. Thus, it is necessary to develop new equations for model industrial operations. The purpose of this study is to develop an empirical model for industrial demethanizer tower which is malfunctioning due to an error in the design in one of its plates. A nonlinear statistical model was designed to predict the pressure variation in the column, and consequently, the flooding conditions. This model was validated using industrial data to predict the maximum loads in the column.