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.
Highlights
The gear transmission system has the advantages of high precision, efficiency, stability, etc. as well as being is widely used in aerospace, transportation, energy equipment and other fields
In order to solve the above problems, Saxena et al [9] established a dynamic model of single-stage gear transmission system based on the finite element method
To analyze the vibration characteristic differences of a gear transmission system with gear and shaft cracks, first, the time-varying meshing stiffness of a gear crack fault was solved via finite element method (FEM) and the stiffness of the shaft section with a breathing crack was derived
Summary
The gear transmission system has the advantages of high precision, efficiency, stability, etc. as well as being is widely used in aerospace, transportation, energy equipment and other fields. Meng et al [8] calculated the meshing stiffness of gear under the failure of tooth surface spalling and crack by potential energy method, and analyzed the fault characteristics. To analyze the vibration characteristic differences of a gear transmission system with gear and shaft cracks, first, the time-varying meshing stiffness of a gear crack fault was solved via FEM and the stiffness of the shaft section with a breathing crack was derived. Considering the shaft flexibility, the two-stage gear drive system with gear and shaft cracks were established respectively and its vibration characteristics were studied. Bearing nodes are respectively located at nodes 5, 13, 14, 22, 23 and 31, gear nodes are located at nodes 7, 16, 20 and 29, among which node 7 and node 16 constitute the first stage mesh element, node 20 and node 29 constitute the second stage gear mesh element
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