| The vibration isolation system with limiters is the most common method to effectively suppress the vibration of ship equipment.The vibration of ship equipment can be effectively suppressed by using the limiter,and the working precision of the ship equipment can be maintained.At the same time,the reliability of the ship equipment can be improved and the working performance of the ship can be improved.The choice of reasonable parameters of limiters is always a puzzle for engineering design.In this paper,the dynamic model of single degree of freedom limitation vibration isolation system with ship equipment is established based on spring-dashpot model,the influence of the clearance and stiffness of the limiter on the dynamic performance of the system is studied.On this basis,the test rig of the limitation vibration isolation system with ship equipment is designed,and the impact experiment is carried out.The influence of parameters of system on dynamic response under sinusoidal plus impact excitation and random excitation is analyzed by simulation method.Then,a three degree of freedom model is established,and the influence of the installation clearance,stiffness and mass of the limiter on the dynamic response of system is analyzed.At the same time,the dynamic response of system is also analyzed under sinusoidal foundation excitation and sinusoidal plus impact excitation.In order to study the limitation vibration isolation system with ship equipment more truly,a finite element model was established based on LS-DYNA finite element software.The natural characteristics of the system and the influence of the installation clearance and stiffness of the limiter on the dynamic response of system under various load excitations are analyzed.The main contents of the thesis are as follows:(1)Vibration characteristics analysis of isolator-limiter single degree of freedom system.Firstly,a single degree of freedom vibration isolation system model with limiters is established,and the dynamic response of the system under the contact model and the Spring-dashpot model in the literature are compared.It is proved that the Spring-dashpot model has better accuracy.Based on Spring-dashpot model,a single degree of freedom vibration isolation system model with bilateral limiters is established,and the influence of clearance and stiffness of the limiter on the dynamic response of the system under sinusoidal foundation excitation is analyzed.(2)The dynamic characteristics analysis of isolator-limiter single degree of freedom system under different excitation loads.The test rig of limitation vibration system with ship equipment is designed and the impact test is carried out.The influence of the installation clearance and stiffness of the limiters on the dynamic response of the system is discussion.The influence of the installation clearance and the stiffness of the limiter on the dynamic response of the system under sinusoidal foundation excitation is studied by simulation.The effects of the amplitude of impact excitation,the pulse width coefficient(the ratio of shock time to impact period)and the period ratio(the ratio of impact excitation period to sinusoidal excitation period)on the dynamic response of the system are analyzed,and the effects of the parameters of the limiter on the dynamic response of the system under random excitation are also analyzed.(3)The dynamic characteristics analysis of isolator-limiter multi degree of freedom system.Based on the model of single degree of freedom vibration isolation system with limiters,a three degree of freedom vibration isolation system model considering the mass of the limiter is established,and the influence of the clearance,stiffness and mass of the limiter on the dynamic response of system under sinusoidal foundation excitation is analyzed.Furthermore,the influence of parameters of the impact excitations on the dynamic response of the system under sinusoidal plus impact excitation is further analyzed.(4)The dynamic characteristics analysis of isolator-limiter system based on LS-DYNA.In view of the fact that the lumped mass model can not effectively simulate the real vibration isolation system with limiters,the finite element model of the vibration isolation system with limiters is established based on LS-DYNA finite element software.The natural characteristics of the vibration isolation system are analyzed,and the influence of the installation clearance and stiffness of the limiter on dynamic response of the system under various load excitations is discussed.The research shows that reducing the installation clearance of the limiter or increasing the stiffness of the limiter will reduce the displacement of the system. |
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