轴向可伸输液曲管平面内振动的波动方法研究

在轴线可伸长假定的基础上，采用Timoshenko曲梁模拟弯曲管道，建立了输液曲管平面内振动的动力学方程；应用波动方法对所建立的振动模型进行了求解；获得了曲管内振动波的传播和反射矩阵，提出了计算轴向可伸输液曲管平面内振动固有频率的数值方法。算例分析中，计算了两端固定半圆形曲管在四种不同流速下的前五阶固有频率，结果表明，与轴线不可伸曲管的结果不同，两端固支轴线可伸曲管不会因为管内流速过大发生屈曲失稳。

Wave propagation method for in-plane vibration of axially extensible curved pipe conveying fluid

Taking the curved pipe as curved Timoshenko beam, the dynamic equations of in-plane vibration of curved pipe conveying fluid was deduced based on axially extensible assumption. The wave propagation method was applied to analyze the above vibration equations. After establishing the wave propagation and reflection matrices, the numerical method for calculating the natural frequency of axially extensible curved pipe’s in-plane vibration was proposed. In the example, the first five natural frequencies of clamped-clamped semi-circular pipe conveying fluid were obtained under four different fluid velocities. The results shown that unlike the axially inextensible curved pipe conveying fluid, the bulking instability caused by high fluid velocity do not occur in the axially extensible curved pipe conveying fluid supported at both ends.