Research On High-Static-Low-Dynamic Vibration Isolator For Ship

High-static-low-dynamic stiffness vibration isolation technology is a new low frequency nonlinear vibration isolation technology,which has good low frequency vibration isolation performance and advantages.The high-static-low-dynamic stiffness vibration isolation system has a variety of structures.The main difference lies in the design of negative stiffness components,and there are many differences in structure,material,combination mode and so on.In this thesis,the marine high-static-low-dynamic stiffness vibration isolator is studied.The buckling circular plate is taken as the negative stiffness.The main work contents are as follows:1.This thesis analyzes the influence of ship noise caused by vibration on the ship,introduces the main noise sources of ship noise,and leads to the importance and necessity of ship vibration and noise reduction.Combined with the limitation of ship environmental space and the main means of vibration and noise reduction,this thesis mainly introduces several common forms of ship vibration isolation,and leads to the research status of high-static-low-dynamic stiffness vibration isolation technology,Then,based on the principle of high-static-low-dynamic,a marine high-static-low-dynamic stiffness vibration isolator with buckling circular plate as negative stiffness mechanism is proposed.2.The principle of high-static-low-dynamic stiffness vibration isolation techno-logy is described.In view of the limitation and complexity of ship space and the problem of low-frequency vibration isolation,a vibration isolator with small volume and simple structure is designed.Combined with the effectiveness of HSLDS in low-frequency vibration isolation,a marine high-static-low-dynamic vibration isolator with simple structure and certain bearing capacity is proposed.A three-dimensional model of marine high-static-low-dynamic stiffness vibration isolator is designed and simplified.The linear and nonlinear buckling analysis of the buckling circular plate as a negative stiffness mechanism is carried out,and the nonlinear buckling analysis of the marine high-static-low-dynamic stiffness vibration isolator is carried out.The analysis results show that the buckling circular plate has negative stiffness characteristics,and the marine high-static-low-dynamic stiffness vibration isolator has the effect of quasi-zero stiffness near the static equilibrium position.3.The dynamic characteristics of marine high-static-low-dynamic stiffness vibration isolator are studied,and the expression of transmissibility is obtained.The effects of stiffness ratio,damping ratio and exciting force on transmissibility under rated load are analyzed;The influence of stiffness ratio,damping ratio,exciting force and offset on the transmissibility under overload or underload condition is analyzed.The results show that the exciting force will make the performance of the vibration isolator more complex under overload or underload condition,and the change of offset may lead to the instability of the vibration isolation system.Increasing the stiffness ratio and reducing the damping ratio can improve the low-frequency vibration isolation effect.4.Firstly,the static experimental analysis of high-static-low-dynamic stiffness vibration isolator is carried out to verify its quasi-zero stiffness static characteristics.Then the vibration transmissibility experimental analysis is carried out,and the transmissibility curves of linear spring isolator and marine high-static-low-dynamic stiffness isolator are compared and analyzed.The results show that the vibration isolation performance of marine high-static-low-dynamic stiffness isolator is better than that of linear spring isolator.In the process of experiment,the skipping phenomenon is also verified by forward and backward frequency sweeping of high-static-low-dynamic stiffness vibration isolator.