输液曲管平面内振动的波动方法研究

采用Flügge曲粱模拟弯曲管道,推导了管内流体的加速度,在总体轴线不可伸长假定的基础上建立了曲管平面内振动的动力学方程;采用波动方法,获得了曲管内振动波的传播和反射矩阵,提出了计算曲管平面内振动固有频率的数值方法.算例分析中,通过计算两端固定半圆形曲管的临界流速并与已有文献结果对比,验证了论文方法的正确性.最后,计算了两端固定半圆形曲管在四种不同流速下的前四阶固有频率,结果表明,管内流速的增大会降低管道的固有频率,当流速增大到某一特定值时,管道的一阶固有频率消失.

WAVE PROPAGATION METHOD FOR IN-PLANE VIBRATION OF CURVED PIPE CONVEYING FLUID

The Flügge curved beam was applied to approximate the curved pipe,and the fluid acceleration was deduced.Based on total inextensible assumption,the dynamic equations of in-plane vibration of curved pipe conveying fluid are established.After establishing the wave propagation and reflection matrices,the wave propagation method for calculating the natural frequency of curved pipe’s in-plane vibration was proposed.In the example,the critical velocity of a semi-circular pipe with clamped support at both ends was calculated.Comparison between the result presented in this paper and corresponding data in existing literature shows good agreement.Finally,the first four natural frequencies of clamped-clamped semi-circular pipe conveying fluid were obtained in six different cases of fluid velocity.The results showed that the increasing fluid velocity can decrease the natural frequencies of pipe,and the first natural frequency vanishes when the fluid velocity increases to a certain value.