船舶推进轴系纵向振动抑制研究

Study on Suppression of the Longitudinal Vibration of Ship’s Propulsion Shafting System

针对船舶轴系的纵向振动情况,建立"螺旋桨—轴系"纵向振动的动力学模型,并推导出其前3阶模态振型。同时,建立轴系的有限元模型,并将计算结果与解析解进行对比。提出用动力消振的方法对船舶轴系的纵向振动进行抑制。通过对实际转速下轴系纵向振动情况的仿真模拟,发现在船舶正常工作范围内,轴系的实际振动状况与其1阶模态十分接近,于是利用轴系纵向振动的响应在其第1阶模态处进行截断,列出轴系加装动力吸振器之后的动力学微分方程,并推导出加装动力吸振器后系统的响应表达式。针对系统的响应公式,设想利用磁流变弹性体材料制作宽频动力吸振器,并进行简单的概念设计。提出的设计方案为船舶推进轴系振动抑制提供一种新的思路。

The dynamic model of ship＇ s propeller-shafting system for longitudinal vibration analysis was established. Its first three-order modals were derived. Then, the finite element model of the shafting system was established.. The computation results were compared with the analytical solution. Afterwards, a method to suppress the longitudinal vibration of the ship shafting using dynamic absorbers was put forward. By simulating the longitudinal vibration of the shafting under the actual speed of the ship, it was found that the actual vibration is very close to the first-order modal vibration. So, the response of the longitudinal vibration of the shafting was truncated at the first-order modal to approximate the real vibration. The dynamic differential equation of the shifting with the additive absorbers assembled was established, and the response expression of the shifting was deduced. Finally, an idea to make broadband dynamic vibration absorbers using magneto-rheological elastomer was proposed. And a simple conceptual design was provided. The presented design scheme provides a new idea for vibration suppression of the propeller-shifting system.