Global sensitivity analysis and multi-objective optimization of vibration isolation performance for double-layer casing herringbone planetary gearbox

Optimizing vibration isolation for high-performance ships is focused on in this study by enhancing the double-layer casing herringbone planetary gearbox. To improve the accuracy and efficiency of the gearbox dynamics modeling process, a novel flexible condensed dynamic model of the gearbox casing, incorporating vibration isolators, is developed using Component Mode Synthesis (CMS) and integrated into the gear transmission system's dynamic model. Comprehensive Global Sensitivity Analysis (GSA) reveals that vibration isolator parameters significantly impact vibration isolation performance, while the sensitivity indices (e.g., Sobol indices) of other parameters remain below 1%, indicating negligible influence. Optimal parameters for vibration isolators are determined through multi-objective optimization combined with the Entropy-Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method, providing a robust framework for balancing multiple objectives to achieve optimal vibration isolation performance. Specifically, optimization enhances the modal decoupling ratio and maintains dominant modal contribution up to the sixth order. The optimized gearbox demonstrates a 25.32% greater vibration level difference (VLD) across the isolation system, indicating a significant reduction in transmitted vibration. Additionally, the inner shell tilt amplitude ratio is reduced by more than 0.28%, contributing to improved stability. The innovative integration of sensitivity analysis and multi-objective optimization in this study offers a reliable and effective approach to advancing vibration isolation design in marine gearboxes.