Study On Shock-resistant Of Floating RAFT System And Transient Noise Of Ship Under Ice Floes Impact

With the continuous improvement of the performance and destructive power of weapons in the water,the energy of non-contact explosion in water is getting larger and larger,and the ability of ships to resist explosion shock should be correspondingly improved.The vibration isolation system is an important aspect of the Navy's shock-resistant research,and it is of great significance to improve the ship's shock-resistant ability.Therefore,the research on shock-resistant of vibration isolation system has very practical significance for the ship equipment.In addition,with the global climate change and the "Ice Silk Road" proposed,the Arctic and Antarctic scientific research,tourism,military activities are increasing,China will inevitably strengthen the military and economic presence in the two poles.However,when sailing in the ice area,the ship will inevitably collide with the ice layer,and the transient noise will not only affect the cabin comfort,but also cause acoustic fatigue of the electronic components.Therefore,research on the mechanism and characteristics of ship transient noise is also urgently needed.Firstly,the impact isolation model of the vibration isolation and impact system and the current three shock response research methods are described.The time domain simulation method can accurately simulate various nonlinear components.The standard on which the current impact analysis is based is introduced,and the method of converting the impact spectrum into a time history curve is described.At the same time,the applicability of two transient methods(direct method and modal method)for shock response time domain analysis is compared.Secondly,the floating raft isolation system is established to perform modal analysis,which provides a basis for damping setting of shock response analysis.The shock response calculation shows that the shock-resistant design of the floating raft vibration isolation system is qualified.In order to optimize the vibration isolation design of the floating raft system,the influence of the change of system properties on the shock response of the marine floating raft system is analyzed.The comparison of the calculation results can guide the design of the floating raft system parameters of the marine generator set.Thirdly,the floating raft isolation system with limiter is established,and the system shock response with the upper and lower limiters respectively is compared.In order to further analyze the influence of the upper and lower limiter parameters on the shock response,the effects of different stiffness and different gaps of the limiter on the shock resistance of the floating raft system are compared when the upper and lower limiters are used separately.Fourthly,the theory of virtual mode synthesis method is briefly introduced,and the statistical energy model of the full-turn tugboat is established.The excitation and structural parameters of the ship are listed.The ice floe collision load is simplified into a triangular wave time domain curve,and the shock response and cabin noise of the hull are calculated.On this basis,the effects of ice flotation cycle and amplitude on hull shock response and cabin transient noise are analyzed.Finally,the ship noise control technology is briefly introduced,and from the perspective of suppressing the shock response of the floating ice collision area,the transient noise is reduced,and the influence of changes of plate thickness,damping,rib reinforcement on shock response and cabin transient noise are analyzed.Through the research work in this paper,the time domain simulation method and virtual mode method are comprehended more deeply,and the influence of relevant parameters on the impact response of floating raft system and transient noise of cabin under floating ice collision is revealed,which is resistant to ship vibration isolation system.The study of shock-resistance and cabin transient noise has certain reference value.