Comparative Study on Dynamic Characteristics of Two-Stage Gear System With Gear and Shaft Cracks Considering the Shaft Flexibility

Abstract

To analyze the vibration characteristic differences of a gear transmission system with gear and shaft cracks, an improved computational method for deriving the shaft stiffness matrix with breathing cracks is developed. Also, the three-dimensional contact model of spur gear with a crack is established via the finite element method (FEM), and its meshing stiffness is calculated. Simultaneously, considering bearing stiffness and shaft flexibility, the finite element dynamic models of two-stage gear transmission system with gear and shaft cracks are established. Based on this, different source fault vibration responses are compared and the influencing factors are explored. In addition, a novel signal processing method based on the particle swarm optimization, maximum correlated kurtosis deconvolution, variational, mode decomposition and fast spectral kurtosis (PSO-MCKD-VMD-FSK) is utilized to extract fault characteristics for the signal-to-noise ratio and uneven energy distribution problems. Results show that a system with gear cracks mainly presents periodic impact in the time domain, while in the frequency domain it impacts rotation frequency modulation near the meshing frequency and its multiple frequencies. However, the shaft crack breathing effect meant that the time domain mainly presents "simple harmonic" modulation, and the rotation frequency and its faulty shaft multiplication occurs in the low-frequency region of the frequency domain. The PSO-MCKD-VMD-FSK method extracts fault features in a strong noise environment and has good robustness. Results identify different source faults and provide a theoretical basis.

Early Fault Diagnosis of Shaft Crack Based on Double Optimization Maximum Correlated Kurtosis Deconvolution and Variational Mode Decomposition

“…As shown in Figure 4(a) and (b), the time domain diagram and frequency spectrum of the simulation signal when the shaft contains a crack are shown. Due to the respiratory effect caused by the shaft crack fault, the time domain diagram shows a simple harmonic waveform [27]. The time domain response shows obvious modulation phenomenon.…”

“…The parameters of CS are set as follows: The dimension of solution D = 2, the number of nests N = 15, the probability of heterozygosity P = 0.1, the maximum number of iterations G = 20, the search upper and lower bounds are based on L > 2f s /f c [27] and T = f s / f c [28]. Where f s is the sampling frequency and f c is the characteristic frequency, and the optimization range is L = [30, 500] and T = [30, 1300].…”

Coupled dynamics characteristics analysis of the marine multi-gearbox system under multi-source excitation

“…4,5 Regarding the coupled between stages, the coupled dynamic characteristics of multi-stage parallel shafts and multi-stage planetary gear systems have attracted the attention of many researchers over the years. Papers by Walha et al, 6 Raclot and Velex, 7 and Shen et al 8 studied the two-stage spur gear system, and found the coupled vibration effect. Zhu et al 9 established the coupled dynamics model of the middle and tail gearboxes of the helicopter.…”

Feature Extraction Based on EWT With Scale Space Threshold and Improved MCKD for Fault Diagnosis

“…Wang et al [46] proposed multipoint optimal minimum entropy deconvolution adjusted to the fault diagnosis of gearbox. Shen et al [47] proposed a novel signal processing method based on the particle swarm optimization, maximum correlated kurtosis deconvolution, variational, mode decomposition and fast spectral kurtosis (PSO-MCKD-VMD-FSK) to extract fault characteristics for the signal-to-noise ratio and uneven energy distribution problems. Zhang et al [48] proposed an improved maximum correlation kurtosis deconvolution based on grasshopper optimization algorithm.…”