船用双层壳体齿轮箱柔性动力学建模及隔振性能分析研究

Flexible dynamic modeling and vibration isolation performance of marine double-layer gearbox casings

双层壳体齿轮箱不仅为齿轮传动系统提供弹性支撑,而且具有减振降噪作用。为了能够高效、高精度地预测双层壳体齿轮箱的减振降噪效果,本文基于模态综合法建立含有隔振器的某船用双层壳体齿轮箱柔性动力学缩聚模型,对比分析齿轮箱的缩聚模型与完全有限元模型的固有特性的差异性,并验证其缩聚模型的有效性。通过双层壳体齿轮箱缩聚模型的模态解耦率、模态贡献度、振级落差和内壳体倾斜度的分析,评估齿轮箱的隔振性能。结果表明:某船用双层壳体齿轮箱在平移方向上模态解耦率均在94.9%以上,模态贡献主要以第二至第六阶振型为主导;在激励频率1~6000 Hz范围内,双层壳体齿轮箱的振级落差可达到34.2 dB;当激励频率小于2000 Hz时,激励频率对振级落差和倾斜度的变化有着显著的影响。

Double-layer gearbox casings can not only provide elastic support for the gear transmission sys⁃tem,but have a good performance in the reduction of vibration noise.To efficiently and accurately predict the control effect of the vibration noise for double-layer gearbox casings,the flexible dynamic condensation mod⁃el of a marine double-layer gearbox casing with vibration isolators was established based on the modal syn⁃thesis method.The condensation model was verified by calculating the natural characteristics of the complete finite element model of the double-layer gearbox casing.The vibration isolation performance of the double layer gearbox casing was evaluated by analyzing the modal decoupling rate,modal contribution,vibration lev⁃el difference,and inner casing inclination of the established condensation model.The results show that the modal decoupling rate of the double-layer gearbox casing in the translation direction is above 94.9%.The modal contribution is mainly dominated by the second to sixth mode shapes.The maximum vibration level difference can reach 34.2 dB in the excitation frequency range of 1-6000 Hz.The excitation frequency has a significant effect on the variations of the vibration level difference and inner casing inclination when the excitation frequency is less than 2000 Hz.