互补集合平均经验模态分解(complementary ensemble empirical model decomposition,CEEMD)作为一种时频特征分析方法,可以较好地提取复杂非线性非平稳信号的故障特征,但其存在虚假分量,很大程度限制诊断过程中的准确性。针对该问题,提...互补集合平均经验模态分解(complementary ensemble empirical model decomposition,CEEMD)作为一种时频特征分析方法,可以较好地提取复杂非线性非平稳信号的故障特征,但其存在虚假分量,很大程度限制诊断过程中的准确性。针对该问题,提出一种基于KL散度(Kullback-Leibler divergence,KLD)的CEEMD虚假分量识别方法(KL-CEEMD)。该方法在原有CEEMD方法基础之上,进一步计算各分量IMF与原信号之间的KL散度值,从而量化各分量与原信号之间的相关性。最后通过对各个IMF的KL散度值进行聚类分析,找出虚假分量和真实分量,最终解决CEEMD的虚假分量问题。为验证KL-CEEMD的有效性,研究搭建风力机传动系统振动试验台,基于该方法对实验台实验数据以及仿真数据进行验证性研究,最终证明所提方法可以很好改善CEEMD的虚假分量问题,能够有效提取出故障信号的真实特性。展开更多
This work deals with super-harmonic responses and the stabilities of a gear transmission system of a high-speed train under the stick-slip oscillation of the wheel-set.The dynamic model of the system is developed with...This work deals with super-harmonic responses and the stabilities of a gear transmission system of a high-speed train under the stick-slip oscillation of the wheel-set.The dynamic model of the system is developed with consideration on the factors including the time-varying system stiffness,the transmission error,the tooth backlash and the self-excited excitation of the wheel-set.The frequency-response equation of the system at super-harmonic resonance is obtained by the multiple scales method,and the stabilities of the system are analyzed using the perturbation theory.Complex nonlinear behaviors of the system including multi-valued solutions,jump phenomenon,hardening stiffness are found.The effects of the equivalent damping and the loads of the system under the stick-slip oscillation are analyzed.It shows that the change of the load can obviously influence the resonance frequency of the system and have little effect on the steady-state response amplitude of the system.The damping of the system has a negative effect,opposite to the load.The synthetic damping of the system composed of meshing damping and equivalent damping may be less than zero when the wheel-set has a large slippage,and the system loses its stability owing to the Hopf bifurcation.Analytical results are validated by numerical simulations.展开更多
基金Project(U1234208)supported by the National Natural Science Foundation of ChinaProject(2016YFB1200401)supported by the National Key Research and Development Program of China
文摘This work deals with super-harmonic responses and the stabilities of a gear transmission system of a high-speed train under the stick-slip oscillation of the wheel-set.The dynamic model of the system is developed with consideration on the factors including the time-varying system stiffness,the transmission error,the tooth backlash and the self-excited excitation of the wheel-set.The frequency-response equation of the system at super-harmonic resonance is obtained by the multiple scales method,and the stabilities of the system are analyzed using the perturbation theory.Complex nonlinear behaviors of the system including multi-valued solutions,jump phenomenon,hardening stiffness are found.The effects of the equivalent damping and the loads of the system under the stick-slip oscillation are analyzed.It shows that the change of the load can obviously influence the resonance frequency of the system and have little effect on the steady-state response amplitude of the system.The damping of the system has a negative effect,opposite to the load.The synthetic damping of the system composed of meshing damping and equivalent damping may be less than zero when the wheel-set has a large slippage,and the system loses its stability owing to the Hopf bifurcation.Analytical results are validated by numerical simulations.
