Research On The Vibration And Radiation Characteristics Of The Ship's Panel Type Structure

The ship structures are always comprised with panels. However when they come to different fluid mediator, the vibration and radiation characteristics will be totally different, so the research on the structure dynamic response and radiation characteristics is really important for the vitality and operating characteristic of an ship. In this article, the following work has been completed based on the Mindlin theory:Combining with the elasticity theory and dynamic response theory, some research on the finite element models has been done based on the Mindlin theory. Take the panels as our research objects, with the modal analysis theory and dynamic response theory, vibration modes and transfer functions can be obtained. Based on the comparison of the transfer function variation trend, the influence of the single vibration mode to the general vibration and the influence of different excitation positions to the transfer function have been analyzed.Suppose that the fluid is ideal and still, consider it with two analysis modals which are compressive modal and incompressive modal, the dynamic fluid forces are turned into add masses of the structural dynamic equation using the coupling FEM/BEM method, so the fluid-structure interaction equation is formed. Based on the Rayleigh integral and the structural surface velocity, the radiation power expression is derived. Define the radiation damping as the ratio between the energy radiated to the outer field and the energy vibrated from the panels, then some numerical examples are used to discuess the influence on the vibration and radiation characteristics under different correlatd factors.The last part is that the radiation mode theory is used to deal with the radiation problems in this article, take the panel which is simply supported in a infinite baffle as our research object, the radiation operator matrix can be decomposed into radiation modes, the radiation power is the weighted sum of the modal radiation power. Thereafter the vibration modes and the radiation modes are combined together to discuss with the dominant radiation modes.