TMD Control Of Hull Total Vibration

Hull vibration is one of the main forms of failure of ship structure,which has great influence on the work,life of crew,normal operation of shipborne equipments,as well as the combat ability and survivability of ships.At present,there are mature and effective methods to control the local vibration of the hull structure,but there is no effective control method for the total vibration of the hull structure.Therefore,once a ship has a total vibration problem,it can not be solved.Tuned mass damper(TMD)is a kind of commonly used vibration control device,which is very effective for a given frequency.Now,tuned mass dampers have been gradually introduced into the field of ship and marine engineering,but the application of them in the control of hull total vibration has not been found yet.In this paper,the TMD is used to control the total vibration of the hull,combining with the simplified model verification analysis and the simulation analysis of the solid model.From the analysis of the mass and the position of the TMD,the vibration control ability of single mass damper,mutiple tuned mass damper(MTMD)and pounding tuned mass damper(PTMD)is studied,and some practical conclusions are drawn.The verification analysis model of ship beam and the simulation analysis model of ship are established,and the horizontal and vertical bending vibration under the first order natural frequency is controlled by a single mass damper.Based on the analysis of ship hull response,this paper investigates whether the total vibration of the hull under the control of a single mass damper conforms to the extended fixed-point theory,and the influence of two key factors,the position and the mass,on the vibration control effect of the tuned mass damper.The response of key nodes was investigated to analyze the effect of different locations on the vibration control effect by selecting tuned mass dampers at different locations.In order to analyze the influence of different mass on the vibration control effect,the best control position is chosen,tuned mass dampers of different mass are applied and investigate the response of key nodes is investigated.Double mass dampers are used to control the horizontal and vertical bending vibration of a ship at first order natural frequencies.The optimum position is chosen to install double mass dampers.Based on the analysis of ship hull response,this paper investigates whether the total vibration of the ship under the control of the double mass dampers conforms to the extended fixed-point theory,and compares the vibration control effect of the double mass dampers of the same mass with that of the single mass dampers.The control stability of the double mass dampers is investigated by analyzing the control effect of the vibration system under the sudden conditions such as change of the spring stiffness,the damping coefficient and the natural frequency of the main vibration system.A simplified hull model is used to study the vertical bending vibration of a ship under the first order natural frequency by pounding tuned mass damper.The total vibration of hull subjected to large harmonic excitation force is analyzed and compared with that of a single mass damper to investigate whether the pounding tuned mass damper has a better vibration suppression effect.The effects of the stiffness of the impact limiter,spring stiffness and damping coefficient on the vibration control efficiency of the pounding tuned mass damper are analyzed.