Experiment And Application Research On Vibration Resistance Performance Of Ship Composite Structure

The vibration of ship structure will produce a lot of adverse effects, for example, the shafting vibration can destroy the stability of shaft system, equipment vibration can destroy its precision and then shorten its life and etc. At the same time, vibration often associates with noise. On the one hand, the air noise produced by vibration affects working and living comfort of the crew. On the other hand, radiation noise caused by the interaction with surrounding fluids and hull structure vibration transferred affects the stealth of ship. It is crucial to take measures to reduce the vibration, meanwhile, noise reduction is achieved.Usually, the vibration reduction measures of large structures consisting of stiffened thin shell are mainly pasting damping layer and inserting blocking masses. Pasting damping layer reduces vibration by dissipating the structural vibration energy, however, inserting the blocking masses in the shell reduces vibration by the reflection and transmission of the vibration wave resulted from interrupting structural continuous and causing impendence mismatch. The paper researched the vibration resistance performance of hollow cross-section blocking masses composite structure from two aspects of experiment and application. On one side, the vibration resistance performance of the composite structure was researched by vibration transfer experiment on the simple plate and complex hull-pedestal structure. On the other side, acoustic vibration characteristic was researched by applying the vibration resistance structure in the double cylinder shell.Firstly, the vibration transform experiment on the simple thin plate was carried out. Taking the vibration transfer function and insertion loss as the evaluation criterion to study the vibration resistance performance of hollow cross-section blocking masses, the vibration reduction performance of microcellular foaming butyl rubber and the composite vibration resistance performance of composite structure. Moreover, the vibration transfer experiment on complex hull-pedestal structure was carried out. Taking the mechanic admittance and insertion loss as the evaluation criterion to study the vibration resistance performance of hollow cross-section blocking masses, the vibration reduction performance of pasting the damping layer and the vibration resistance performance of hollow blocking masses with filling particle and the composite vibration resistance performance of composite structure were researched.Secondly,the FE-SEA hybrid model of the double cylinder shell as the typical structure of underwater aircraft based on the wave coupling analysis was built to study the acoustic vibration characteristic. The influence of different style pedestals and different medium between the outer shell and inner shell on acoustic vibration characteristic was studied, as well as the acoustic vibration characteristic under the exciting of power equipments. In addition, an effective forecast method of acoustic vibration characteristic under a variety of exciting sources was pointed.Finally, the hollow cross-section blocking masses composite structure was applied in the double cylinder shell built upside to research the influence on acoustic vibration characteristic. The influence of inserting with different cross-section blocking masses and different position on acoustic vibration characteristic was studied when taking the cabin pedestal as the research object. The vibration resistance performance of hollow cross-section blocking masses, the vibration reduction performance of microcellular foaming butyl rubber and the vibration resistance performance of composite structure were studied when taking the cabin pedestal as the research object. A new connection structure was proposed when extended the thought of inserting the blocking masses around the pedestal. In addition, the acoustic vibration characteristic of the new connection consisting of inserting the hollow cross-section blocking masses at the connection of inner shell, outer shell, platform structure and cabin was studied.Briefly, the paper researched the vibration resistance performance of composite vibration resistance structure from the point of experiment and application. The results indicated that the vibration resistance performance of composite vibration resistance structure is obvious and better than single vibration reduction method. It can effectively reduce the structure vibration of ship thus achieving the purpose of vibration and noise reduction. The research achievement has reference value for acoustic design of ship structure.