改进NOFRFS加权贡献率在转子碰摩故障诊断的应用

Application of the Improved Nofrfs Weighted Contribution Rate Inthefaultdiagnosisofrotor Rub-impact

作为转子系统的一个常见故障,转子和定子之间的碰摩导致转子系统表现出很强的非线性。因此,从具有碰摩故障的转子系统中获得的振动信号包含微弱的高阶非线性成分,这些成分很难用传统的线性方法进行表征。非线性输出频率响应函数(nonlinear output frequency response functions,NOFRFs)是一种在频域上分析非线性系统的有效方法,现已被许多学者应用于非线性系统的故障诊断。文中引入Kullback-Leibler(KL)散度的概念,提出了一种基于KL散度改进的NOFRFs加权贡献率(NWKL)的新方法。并在此方法中提出一个新指标—基于KL散度的改进的NOFRFs最优加权贡献率(KLRm),用以评估转子系统中碰摩故障的严重程度。通过转子系统仿真分析和实验验证,表明NWKL方法对转子系统碰摩故障具有很高的适用性和有效性。并且指标KLRm对于不对中故障具有很高的灵敏度,它可以全面地表征转子系统的非线性特性。该方法在转子碰摩的检测和评价中具有重要的意义和潜在的应用价值。

As a common fault of the rotor system,the rub-impact between a rotor and a stator causes the rotor system to exhibit strong nonlinearities.Therefore,the vibration signals obtained from a rotor system with the rubbing fault contain weak high-order nonlinear components,which are difficult to be characterized by traditional linear methods.The nonlinear output frequency response functions(NOFRFs)are an effective approach for analyzing nonlinear systems in the frequency domain,and has been applied by many researchers in the fault diagnosis of nonlinear systems.In the present study,the concept of Kullback-Leibler(KL)divergence is introduced to NOFRFs to develop a novel method named the improved NOFRFs weighted contribution rate based on KL divergence(NWKL).And it is employed to detect the rotor system with a rub-impact fault.As a new index extracted by NWKL,the improved NOFRFs optimal weighted contribution rate based on KL divergence(KLRm)is proposed to evaluate the severity of rub-impact faults in rotor systems.The simulation and experimental results verify the effectiveness and superiority of NWKL in diagnosing rub-impact.The KLRm has higher sensitivity and can comprehensively represent the nonlinear characteristics of the rotor system.The methods presented in this paper have important significance and potential application values in the detection and evaluation of rotor rub-impact.