充液管道系统的模态分析

THE MODAL ANALYSIS OF THE LIQUID-FILLED PIPE SYSTEM

考虑管道与液体之间的泊松耦合与连接耦合 ,推导了低频情况下的充液直管轴向、横向振动传递矩阵与弯管单元的传递矩阵 ,引入了弯管弯曲因子 .对一“L”形充液管系进行了研究 ,使用ANSYS有限元分析软件与传递矩阵法计算了两种边界条件下充液、充气管系的模态频率与模态振型 .结果表明 ,气体与管道之间的耦合作用对管系模态的影响可忽略 ;而对充液管系而言 ,固液耦合作用不能忽略 .

The Transfer Matrix Methed (TMM) for the modal analysis of the beam like liquid filled pipe system is presented. The transfer matrices of the axial and flexible modes of the pipe are derived with considering Poisson coupling and the effect of the shear deformation and rotary inertia in the axial and lateral direction respectively. The junction coupling is involved through the derivation of the transfer matrix of the elbow. The effect of the flexible factor on the elbow is studied. The modal analysis of a “L” type pipe system filled with liquid and gas is carried out under two different boundary conditions. At the same time the natural frequency and mode of the system filled with gas are calculated by using ANSYS software. The results show that the effect of the gas on the system modal can be ignored. But the coupling between the liquid and the structure may result in large change in the natural frequencies.