How Does Vibration Isolator Affect Marine Double-Layer Gearbox Case? A Dynamic Response Analysis

Purpose This study attempts to propose an internal vibration isolation technology applied to the marine gearbox by exploring the impact of vibration isolators on the vibration response of gearbox case. Methods The spring element COMBIN14 of ANSYS software is used to simulate the vibration isolators installed between the inner and outer shells of the marine double-layer gearbox case. The modal of the marine double-layer gearbox case is calculated by the Lanczos method. The structural vibration responses of two gearbox cases are calculated by the modal superposition method. The effect of the vibration isolator on the gearbox case is evaluated by the vibration acceleration and acceleration-vibration level difference. Results The first six modal vibration modes of the double-layer gearbox case are inner shell vibration. The vibration acceleration of the double-layer gearbox case on the outer shell is less than that of the single-layer gearbox case. The vibration acceleration is positively correlated with the vibration-isolator number on the outer shell. The vibration reduction performance of the double-layer gearbox case decreases with the increase of the vibration-isolator stiffness when the stiffness is in the range of 1.0 x 10(7)-1.5 x 10(9) N/m. The acceleration-vibration level of the double-layer gearbox case is negatively associated with the number and stiffness of vibration isolators. Conclusions The vibration isolator plays an important role in the vibration reduction of the marine gearbox. The performance of the vibration isolator would be weakened as the number and stiffness of vibration isolators increase.