Research And Application Of The Structure With Periodically Perforated Damping

As the global industrialization, pipeline system in urban,water conservancy,machinery, air, ocean engineering, and other fields, gets a wide range of applications.Itis becoming an indispensable part in the large building and mechanical structure.Thevibration of piping system affect the regular operation of the structure, even for somelarge equipment such as the survival of submarine, etc,it brings the serious influence tothe normal work.At present, the vibration can be reduced more effectively only in high frequencythan in low frequency.Because the noise in high frequency decreases quickly as itsspread,however in the low frequency it changes little. So the vibration of the structurein the low frequency is a problem that is urgent need to solve. Especially for some largemechanical structures, such as submarines, vibration of piping systems in the lowfrequency is not only related to the whole structure’s noise, but also affect the ability tosurvive.This article poses a kind of damping structure with periodical perforated. Thisstructure can improve the situation that the vibration can be reduced hardly in the lowfrequency. At first the theoretical models of the damping structures are established inthis paper.Because the whole structures are extremely complex. We building simplifiedmodel based on the assumptions and at last get the design formulas about loss factor forthe damping wih the different roles.The theoretical calculation is based on the model which is simplified,but the actualmodel is extremely complex, to get more accurate results, the finite element method isselected to analyse the whole system. Strain energy method is applied in the FEM. Thistheory is more applied in civil engineering field than machinery field. after building theFEM model and write APDL,the paper analyses the whole structure. At last we getsome useful results for the design of the pipe system:Structure with periodically perforated damping is more effective to decrease thevibration of the pipe system than the pipe with the normal damp. For structures withdifferent periodically perforated dampings, for0~550Hz, the result of vibrationdecrement for the damping with the round holes is better, and in550Hz~1000Hz, theresult is better for the damping with the rectangular hole. In the same drilling rate, thedecrement of the structure’s vibration is more effective in the damping with rectangularholes more than the round holes.Finally,the research results are validated by the experiments.