Research On Vibration Reduction Method For Simply Supported Rectangular Thin Plate Excited By Multiple Vibration Source

The diesel engine, propellers and working machines (such as motors, air blower and pumps etc.) were the internal source of the deck vibration. This thesis focused on the method to reduce the vibration of the deck caused by working machine. Generally, the solution to reduce the vibration of the ship is to add isolators or power dynamic damper, but these methods has two limitations in the application. This thesis presented a method through mutual inhibition between the vibration source to achieve the purpose of reducing the deck’s vibration which means this method does not add additional damping device and has the advantages of low cost, energy savings.The objective of this thesis was that the system was simplified as forced vibration of a simply supported rectangular thin plate forced vibration, and the fundamental of using suppressing vibration source strength to reduce the vibration of the sheets under a plurality of vibration sources excitations was presented and testified.This thesis included those research contents:firstly, the fundamental of using suppressing vibration source strength to reduce the vibration of the sheets was presented. Secondly, rectangular sheets were discretized and dynamics equations which set the total kinetic energy of a rectangular sheet as the objective function were established. Finally, this thesis presented the study of the effect of vibration source position and phase difference to the vibration of the sheets by applying numerical analysis and experimental methods.The results indicated that the vibration source position and phase difference have more influence on the vibration of the sheets, so the effective solutions to reduce the vibration of plate can be done by controlling the vibration source position and phase difference reasonably. The experiment is performed and the results presented that the vibration-reduce method by suppressing vibration source strength proposed in the thesis were effective and reliable.The main contribution of this paper were:(1) For the deck vibration, a new valid vibration reduction method was proposed, and the problem of local vibration of the ship could be fundamentally solved by making use of the vibration sources. (2) Numerical analysis and experimental methods were taken to verify the effectiveness of the vibration reduction method by suppressing oscillator strength.