中间支承输流管道自由振动的有限元分析

基于Euler梁模型研究中间支承输流管道的动力学特性。首先,利用虚功原理,建立系统动力学有限元方程。然后,分析了支承刚度、流体离心力、预应力等因素对管道振动的影响。结果表明:支承刚度对管道系统动力学特性有重要影响,管路设计时须着重考虑;揭示了流体离心力是造成固有频率随流速增大而降低的根本原因;流体科氏力对各阶固有频率影响较小;预应力对振动的影响不可忽略,尤其是第一阶固有振动。

FINITE ELEMENT ANALYSIS ON FREE VIBRATION OF FLUID-CONVEYING PIPES WITH INTERMEDIATE SUPPORT

The dynamic characteristics of fluid-conveying pipes with intermediate support was studied based on Euler beam model. Firstly, utilizing virtual work principle, the finite element dynamic equation of pipe system was established. Then, the influence of stiffness of support, fluid centrifugal force and pre-stress on pipe vibration was analyzed. The results showed that the stiffness of support had a significant effect on the dynamic characteristics of the pipe system, which should be taken into account serious lyin pipe design. It suggested that the centrifugal force of fluid was the root cause of the fact that natural frequencies decrease with the increase of flow velocity. The fluid Coriolis force had little effect on the natural frequencies of each order. The influence of pre-stress on vibration couldn''t be ignored, especially the first natural vibration.