Shock Response Of The Double-layer Vibration Isolation System

With the development of science and technology, the attack range and radius of damage of the underwater weapons has been improved too. The warships and submarines could be subjected to underwater non-contact explosion, it is important to improve the performance of the shock absorber to protect the miassile from the uherwater non-contact explosion. The double-layer vibration isolation system is widely used in the ship-borne equipment especially in submarine equipment for the good performance of shock and vibration isolation. The shock response of double-layer vibration isolation system is under the synthetical influence of many parameters, such as mass ratio,stiffness ratio,the first stage isolator frequency and the placement of rubber pads,which bring a lot of difficulties in its analysis and design. The relationship between shock reponse and design parameters of the double-layer vibration isolation system is studied through four simplied models of it: two-degree freedom model,beam and spring model,beam and rectangular section cylinder,solid and shell element model.The shock reponse of two-degree freedom model is analysed under different mass ratio,stiffness ratio,damping ratio and the first stage isolator frequency. The result shows that the second stage isolator relative displacement of undamped two-degree freedom model decreases with the raising of mass ratio under differnet stiffness ratio. The accelation of the vibration isolation object change with the mass ratio is identical with laws of the first stage isolator relative displacement varying witn mass ratio. A better shock response result can be obtained with appropriate damping ratio. The shock reponse of,beam and spring model is also analysed under different mass ratio,stiffness ratio,damping ratio. It indicates that the shock response result of two-degree freedom model,beam and spring model with different mass ratio is in good agreement with each other. The change in the quantity of spring has a little influence on the shock response result of beam and spring model.The shock response result in time domain of the four simplified models is compared with each other. The comparison result indicates that the different simplified models have different filed of application. When the moment resisting ability of the missile and inner tube is strong, it is more reasonable to adopt the two-degree freedom model, solid and shell element model. When the moment resisting ability of the missile and inner tube is weak, it is more reasonable to adopt the beam and rectangular section cylinder,beam and spring model.