推进轴系纵向高承载准零刚度隔振器的研究

Research on Longitudinal High Load-bearing Quasi-zero Stiffness Isolator for Propulsion Shafting

针对船舶推进轴系纵向低频隔振难的问题,将具备负刚度特性的碟簧与正刚度螺旋弹簧并联,设计了一种高承载准零刚度隔振器。建立了轴系-准零刚度隔振系统的动力学方程,利用谐波平衡法求解了系统的稳态响应,并用数值方法验证了求解的有效性。对于系统响应稳定性的问题,首先研究了准零刚度隔振器的非线性刚度、外激励力幅值对系统响应稳定性的影响规律,并结合推进轴系的纵向静变形限制,确定了非线性刚度取值;其次基于静力学理论设计了一组碟簧与螺旋弹簧的结构参数;最后分析了准零刚度隔振器的阻尼比、外激励力幅值对系统响应稳定性的影响规律,并确定了合适的阻尼比。结果表明:当非线性刚度、阻尼比分别设计为1×10^(12) N/m^(3)、0.05时,系统主共振不再出现跳跃现象,稳态响应的解在200 Hz内都是稳定的;在承受10000 N载荷时,准零刚度隔振器仍然可以有效隔离10~200 Hz低频段的振动。

Aiming at the problem of longitudinal low-frequency vibration isolation of ship propulsion shafting,a high-load quasi-zero stiffness isolator was designed based on disc spring with negative stiffness characteristics and positive-stiffness coil spring in parallel.The dynamic equation of the shafting-quasi-zero stiffness vibration isolation system was established.Through the harmonic balance method,the steady-state response of the system was solved,and the validity of the solution was verified by numerical calculation.For the problem of system response stability,firstly,the influence of nonlinear stiffness of quasi-zero stiffness isolator and external excitation force amplitude on response stability were studied,and combined with the longitudinal static deformation of the shafting,the nonlinear stiffness was determined.Then the specific structural and mechanical parameters of the disc spring and the coil spring were obtained through static analysis.Finally,the influence of damping ratio of quasi-zero stiffness isolator and external excitation force amplitude on the response stability of the system were analyzed,the damping ratio was determined.The results showed that when the nonlinear stiffness and damping ratio were taken as 1×10^(12) N/m^(3) and 0.05,respectively,the main resonance of the system no longer jumps,and the solution of the steady-state response of the system was stable within 200 Hz.In the meantime,even with a load of 10000 N,the quasi-zero stiffness isolator could still effectively isolate the vibration in the range of 10 Hz to 200 Hz.