推力轴承轴向刚度对潜艇整艇结构振动与声辐射的影响

Effect on vibration and acoustic radiation of the whole submarine due to elastic coefficient of thrust bearing

针对螺旋桨轴向激励力引起的潜艇结构辐射噪声,在Suboff试验艇模型的基础上,建立包含螺旋桨和轴系结构实体单元的整艇结构模型,为了在激励力和振动传递的路径上采取减振降噪措施并预估其减振降噪效果,在推力轴承内部设置了轴向减振器,通过计算减振器具有不同轴向刚度时潜艇结构的振动和声辐射特性,分析了推力轴承轴向刚度对对潜艇结构振动与声辐射的影响;同时采用质量-弹簧-阻尼系统对轴系纵振模型进行简化,计算了轴系纵振第1阶固有频率,通过与潜艇结构振动与声辐射频响曲线的对比,进一步分析了推力轴承轴向刚度对潜艇结构振动与声辐射的影响规律。得出结论:降低推力轴承轴向减振器刚度,可使轴系纵振第1阶固有频率向低频移动,并使轴系纵振第一阶固有频率附近及以下频段结构振动增大;在中高频段,降低减振器轴向刚度能够明显减小潜艇结构的振动和声辐射,且减振器轴向刚度越低,减振降噪效果越好。

Aiming at the propeller noise which is caused by axial excited force,based on the form of SUBOFF,the propeller--shafting--hull interaction model is established.To adopt measures and predict the effect of shock absorption and noise reduction in the transmission path of the axial excited force,the axial shock absorber is installed inside the thrust bearing.Through calculating the vibration and sound radiation characteristics of submarine structures with different stiffness of shock absorbers,the influence of absorber’s elastic coefficient to the vibroacoustic of the overall submarine is mainly considered.Simultaneous,the mass-spring-damping systems are taken to simplify the longitudinal vibration model of the shafting.Through calculating the shafting’s first order longitudinal vibration natural frequencies,and comparing with the whole submarines’vibroacoustic curves,the practicability of predict the effect regularity on acoustic radiation of the whole submarine due to absorber’s elastic coefficient is analyzed.It is demonstrated that reducing the elastic coefficient of thrust bearing can lead the shafting’s first order longitudinal vibration natural frequencies lower,and the submarine’s vibration lever at and under this frequencies higher;at middle and high frequency ranges,reducing the elastic coefficient of thrust bearing can clearly lead the submarine’s vibration and acoustic radiation lower,and the elastic coefficient lower,the effect of the shock absorption and noise reduction better.