Analysis Of Fluid-filled Pipe Vibration Characteristic And Control

The fluid-filled pipes are widely applied in industrial engineering and our daily life, and have great importance to national economy. But, vibration and noise of the pipe may damage the machines and equipments, and bring inconvenience to people's life. This paper concentrates on the vibrational characteristic study taking the Fluid-Structure Interaction (FSI) into account, and introduces the concept of High-Static-Low-Dynamic-Stiffness (HSLDS). Some theoretical and experimental researches are carried out to test the characteristics of a HSLDS isolator.1. The transfer matrices of the axial, flexible and torsional modes of fluid-filled pipe are deduced considering fluid-structure interaction between pipe and fluid. And the transfer matrix of the elbow is derived according to the discrete model of inextensible theory of the curve pipe. The derivation of the transfer matrices of the lumped mass and elastic supporting are also presented.2. Modal frequency and shape of a"U"shape pipe are calculated with Transfer Matrix Method (TMM) and ANSYS software respectively. The result indicates that Transfer Matrix Method is an effective way to analyze fluid-filled elbow pipe. Performed experiments on pipes with different length and outer diameter, and compared the result with that of TMM. It is showed that the errors of modal frequency with TMM would decrease when pipe length increases or outer diameter decreases.3. The concept of High-Static-Low-Dynamic-Stiffness is introduced and the static and dynamic experiments are carried out on a HSLDS isolator. Force-deformation relationship is tested in static experiment, and motion transmissibility is tested in dynamic experiment. Its performance is compared with that of an equivalent linear system. The result shows that HSLDS isolator can reduce the natural frequency and extend the frequency range of isolation. It also has a lower motion transmissibility which provides higher isolation capability.