【目的】相比直线振动信号,行星轮扭振信号不受行星轮通过效应和信号传递路径的影响,频谱结构更加简单。因此,基于扭振信号开展行星齿轮箱故障诊断有望得到更好的诊断结果。提出一种基于扭振信号调制信号双谱(Modulation Signal Bispect...【目的】相比直线振动信号,行星轮扭振信号不受行星轮通过效应和信号传递路径的影响,频谱结构更加简单。因此,基于扭振信号开展行星齿轮箱故障诊断有望得到更好的诊断结果。提出一种基于扭振信号调制信号双谱(Modulation Signal Bispectrum,MSB)分析的行星齿轮箱故障诊断新方法。【方法】首先,对编码器信号使用希尔伯特(Hilbert)变换方法求解瞬时转速信号;然后,对瞬时转速信号进行MSB分析,寻找最优载波频带;最后,对选取的最优载波频带构建MSB最优载波频带复合谱,并作为行星齿轮箱的故障诊断特征。【结果】试验结果表明,所提出方法可以更直观地反映行星轮的故障状态以及故障信息,验证了该方法在行星轮故障诊断方面的有效性和优越性。展开更多
Biological processes and behaviors of endothelial cells on the inner surfaces of blood vessels are regulated by the stimulation from biochemical signals contained in the blood.In this paper,the transportation of dynam...Biological processes and behaviors of endothelial cells on the inner surfaces of blood vessels are regulated by the stimulation from biochemical signals contained in the blood.In this paper,the transportation of dynamic biochemical signals in non-reversing oscillatory flows in blood vessels is analyzed by numerically solving a nonlinear governing equation for the time-dependent Taylor-Aris dispersion.Results show that the nonlinear frequency-amplitude modulation of the transportation of biochemical signals is more(less) significant when the frequency of an oscillatory flow is close to(higher than) that of an oscillatory signal.Under steady flow,the transfer function for the signal transmission system is obtained,showing that the system is a low-pass filter.Lower inner radius or higher center-line velocity of a blood vessel increases the cutoff frequency of the transportation system.These results suggest the possibility and condition for the 'remote' transmission of low-frequency dynamic biochemical signals in pulsatile blood flows.展开更多
文摘【目的】相比直线振动信号,行星轮扭振信号不受行星轮通过效应和信号传递路径的影响,频谱结构更加简单。因此,基于扭振信号开展行星齿轮箱故障诊断有望得到更好的诊断结果。提出一种基于扭振信号调制信号双谱(Modulation Signal Bispectrum,MSB)分析的行星齿轮箱故障诊断新方法。【方法】首先,对编码器信号使用希尔伯特(Hilbert)变换方法求解瞬时转速信号;然后,对瞬时转速信号进行MSB分析,寻找最优载波频带;最后,对选取的最优载波频带构建MSB最优载波频带复合谱,并作为行星齿轮箱的故障诊断特征。【结果】试验结果表明,所提出方法可以更直观地反映行星轮的故障状态以及故障信息,验证了该方法在行星轮故障诊断方面的有效性和优越性。
基金supported by the National Natural Science Foundation of China (Grant Nos. 11172060 and 10972139)the Fundamental Research Funds for the Central Universities in China (Grant No. DUT12JB11)
文摘Biological processes and behaviors of endothelial cells on the inner surfaces of blood vessels are regulated by the stimulation from biochemical signals contained in the blood.In this paper,the transportation of dynamic biochemical signals in non-reversing oscillatory flows in blood vessels is analyzed by numerically solving a nonlinear governing equation for the time-dependent Taylor-Aris dispersion.Results show that the nonlinear frequency-amplitude modulation of the transportation of biochemical signals is more(less) significant when the frequency of an oscillatory flow is close to(higher than) that of an oscillatory signal.Under steady flow,the transfer function for the signal transmission system is obtained,showing that the system is a low-pass filter.Lower inner radius or higher center-line velocity of a blood vessel increases the cutoff frequency of the transportation system.These results suggest the possibility and condition for the 'remote' transmission of low-frequency dynamic biochemical signals in pulsatile blood flows.
