钟形减振穴的设计研究

对双桨平底船的尾部振动,根据实船螺旋桨脉动压力测试结果,以及金属橡胶板的模型试验与模态分析,设计了钟形减振穴,以减小螺旋桨激起的船舶尾部振动,并在国内的双桨平底船上首次应用获得成功。 文中提出了适用于双桨平底船的螺旋桨脉动压力估算的经验公式,其计算值与实测值相当接近,可供船舶初始设计阶段应用。

STUDY AND DESIGN OF BELL TYPE ANTIVIBRATION DEVICE

Vibration at the afterbody of twin screw flat bottom ship is athorny problem. Results of full scale trials show that the exciting force in the case of blade frequency vibration is due mainly to the propeller.Based on the results of the propeller fluctuating pressure measurements, the rubber-steel composite plate modal tests and mode analysis, the bell type anti-vibration device was designed. These devices have been fitted at the stern above propellers to reduce the exciting force and the hull vibration of a twin screw ship.For this type of ships through research and practical measurements an empirical estimated formula of maximum propeller fluctuating pressure has been established. The results of trials show good agreement between calculated and measurements.The bell type anti-vibration device is concave upwards at the bottom and hence it will increase the clearance between propeller tip and the bottom of ship. This will lead to the reduction in fluctuating pressure. On the other hand, the rubber sheath under the bell absorbs part of the energy due to exciting force. Therefore by employing this device hull vibration can be reduced effectively. The results of full scale trials are most impressive.