推进轴系纵向振动引起的艇体声振特性分析

螺旋桨在艇体艉部不均匀伴流场中旋转产生的脉动推力激励起推进轴系纵向振动，振动经推力轴承基座传递至艇体，引起艇体水下低频辐射噪声。通过建立推进轴系、推力轴承基座和艇体耦合结构模型，分析推进轴系─艇体的耦合振动模态，结果显示，艇体弹性支撑边界条件对推进轴系的纵向振动特性有一定影响。采用基于模态叠加法的有限元结合边界元方法分析推进轴系纵向振动激励下的艇体水下辐射声场，分析表明，艇体第1阶纵向振动模态是参与艇体水下声辐射的主模态。进一步在推力轴承及其基座间安装动力吸振器以减小推进轴系纵向振动向艇体的传递，使艇体水下辐射噪声得到一定程度上的控制。

Analysis of Vibration and Acoustic Radiation of Submarine Hull Induced by Longitudinal Vibration of Propulsion Shafting

The pulsatile thrust of propeller induced by asymmetrical wake field can cause longitudinal vibration of the propulsion shafting. The vibration will transmit through the shafting, thrust bearing and foundation to the submarine hull, and induce the low frequency underwater acoustic radiation of the hull. Considering the coupled effect of shafting, foundation and the hull, the structural model of the propulsion shafting was established. The propulsion shafting submarine hull coupled vibration was analyzed, and the acoustic radiation field of the hull was calculated by FEM/BEM based on the mode superposition method. The results show that the longitudinal vibration mode is one of main modes which participates the acoustic radiation. By instilling a dynamic vibration absorber between the thrust bearing and its foundation, the transmission of longitudinal vibration to the hull can be decreased. The acoustic radiation of hull induced by longitudinal vibration of orooulsion shaftin can be controlled.