低频桨-轴-壳体耦合振动声辐射机理研究

Research on the Vibration and Acoustic Radiation Mechanism of Propeller-Shaft-Hull Coupled Structure in Low-Frequency

为揭示低频桨-轴-壳体水下结构耦合振动声辐射机理,利用三维水弹性力学理论和三维水弹性声学分析软件,从螺旋桨、推进轴系以及壳体结构传递特性出发,分析了各结构低频段模态频率与桨-轴-壳体耦合结构响应频率之间的相关关系,由此提出了桨-轴-壳体结构纵向和横向耦合振动声辐射峰值对应的优势模态。研究表明:螺旋桨桨叶对桨-轴系统的振动影响比较大,尤其是螺旋桨的全桨叶同向伞型弯曲振动对桨-轴-壳体的纵向振动声辐射贡献明显;桨-轴-壳体耦合系统的纵向声辐射声源级曲线峰值主要对应于壳体一阶纵向振动、桨-轴系统一阶纵向振动、壳体二阶纵向振动和螺旋桨全桨叶同向伞型弯曲振动,横向振动声辐射声源级曲线峰值主要对应于壳体弯曲振动及桨-轴系统弯曲振动;低频段螺旋桨纵向单位力引起的声辐射明显大于横向力作用下的声辐射。

To reveal the vibration and acoustic radiation mechanism system in low-frequency, the three-dimensional sono-elasticity software is applied to analyze the relationship between the individ and the propeller-shaft-hull coupled structure response frequency b of propeller-shaft-hull coupled theory and acoustic analysis ual structural modal frequency y the transfer characteristics of the propeller, propulsion shafting and hull. And the dominant modes corresponding to the peaks of vibration and acoustic radiation of the propeller-shaft-hull system under the longitudinal exciting and the lateral exciting are obtained. The results show that the oscillations of the blades have a great influence on the propeller-shaft system, especially the umbrella-form bending oscillation of the blades contributed significantly to longitudinal vibration and sound radiation of the propeller-shaft-hull system. The longitudinal peaks of vibration and acoustic radiation of the propeller-shaft-hull are interrelated to the 1st and 2nd longitudinal modes of the hull, the 1st longitudinal mode of the propeller-shaft system and the 1st umbrella-form bending mode of thepropeller blades. The lateral peaks of vibration and acoustic radiation of the propeller-shaft-hull are interrelated to the bending modes of the hull and the propeller-shaft system. The total acoustic power under longitudinal exciting is significantly higher than that under lateral exciting.