支承刚度对输流管道振动特性的影响分析

Influence of Support Stiffness on Vibration Characteristic of a Pipe Conveying Fluid

为研究实际支承条件下管路系统的振动特性,文中采用一端固支一端具有弹性约束梁的前两阶振型来近似相同边界条件下输流管道的前两阶振型.通过拉格朗日方程推导出了带有弹性约束管道系统的控制方程,利用模态法对其进行求解,分析了支承刚度对梁前两阶振动特征值的影响,并分析了支承刚度对管道固有频率、跨中最大振动位移和动静失稳临界流速的的影响.研究结果表明:支承刚度在0～1 000N/m范围内对固有频率影响不大,当支承刚度大于1 000N/m对固有频率有明显影响;随着支承刚度的增大,管道系统的首次失稳形式由动态失稳变为静态失稳.

In order to study the vibration characteristic of a pipe under the actual boundary condition, the first two modes of a beam with a simple support and an elastic restraint were adopted as a substitute for modes of the corresponding pipe conveying fluid. Through Lagrange＇s equation, the control equation of the pipe with an elastic restraint was deduced and then was solved by the modal method. The paper analyzes the influence of the different support stiffness on the beam＇s first two eigenvalues, and the influence of support stiffness on the natural frequencies and the mid-span maximal displacement. The results show that the support stiffness within natural frequencies, while the support stiffness of the support stiffness, the mid-span maximal the range of 0- 1 000 N/m has less influence on pipes＇ beyond 1000 N/m has greater influence. With the increase displacement decreases.