输流管道耦合动力特性分析

管道中流体和弹性体之间的相互作用是引起管道振动的主要原因，这种流固耦合作用对管道动力特性有直接影响。通过实验和数值分析研究输流管道在流固耦合作用下的振动模态、幅频响应等动力特性的变化规律。根据流体三维波动方程和管道动力学方程之间的耦合关系建立空间输流管道系统的直接流固耦合动力有限元模型，进行管道系统有无流体两种工况下的模态实验。通过和实验结果的对比，验证了输流管道耦合动力学模型的合理性和流体对管道模态的影响，研究了不同频率下流固耦合特性对管道幅频响应的影响及作用机理。发现水介质流体显著降低了管道固有频率，但是在不同频率下流体对管道幅频响应的作用效果并不相同。

Analysis of Dynamic Characteristics of Fluid-structure Interaction in Fluid-filled Pipes

The interaction between fluid and elastic solid in a fluid-filled pipe plays a key role in pipeline vibration. The fluid-structure coupling effect has a direct impact on the pipe dynamic characteristics. In this paper, using experiments and numerical analysis, a fluid-filled pipe system under the fluid-structure interaction is employed to study its dynamic characteristics, such as pipeline vibration modal, amplitude frequency response and so on. According to the coupling relationship of the three-dimensional fluid wave equations and structural dynamics equations, the 3D piping system is modeled as a fluid-solid coupling finite-element model, and the modal testing of the system is carried out considering two different cases, pipeline without water and with water. Comparing the numerical results with test data, the fluid-solid coupling dynamic model is validated and the effects of fluid on the pipeline modal are analyzed. The influence and mechanism of coupling characteristics on amplitude-frequency responses of the pipe system are investigated at different excited frequencies. It is found that the effects of water medium reduce remarkably pipe natural frequencies, but the effects of fluid on pipe amplitude frequency responses are variable at different frequency.