复杂空间载流管道系统流固耦合动力学模型及其验证

 针对飞机复杂管路系统振动分析,提出了一种复杂空间管道系统流固耦合动力学模型,在模型中用梁单元对管道进行了离散,每个节点考虑了x、y、z这3个方向的平动以及绕x、y、z这3个方向的转动,共计6个自由度;在单元中考虑了流固耦合效应,计及了流体流速对管道振动的影响;建立了管道与基础、管道与管道间的弹性连接,以适应多个管道之间的耦合振动分析;模型采用Newmark-β数值积分法获取系统响应。针对实际液压试验台的空间管路系统,利用锤击法进行实验模态分析,将本文模型的仿真结果与实验结果和商用有限元软件ANSYS Workbench的计算结果进行了分析比较,验证了本文模型的正确性。最后,仿真计算了流固耦合作用下流速对管道系统固有频率的影响规律。

Fluid-structure Coupling Dynamic Model of Complex Spatial Fluid-conveying Pipe System and Its Verification

For the vibration analysis of complex aircraft pipe systems, a spatial fluid-structure coupling dynamic model is proposed. In this model the finite element method is adopted, the pipe is modeled using the beam element, and a node has 6 degrees of freedom, which includes the movements along and around the x, y and z directions. The fluid-structure coupling effect is considered, and the effect of fluid flow speed on the structure vibration is analyzed. The connections between the pipe and the base, and the connections between two pipes are considered in order to model the coupling vibration for a multi-pipe. The dynamic responses are obtained through direct numerical integration by using the Newmark-β method. The pipe vibrations due to base excitations, pressure fluctuation, and the fluid-structure coupling effect are also analyzed. The spatial pipe system of a practical hydraulic test stand is used to verify the new model. An experimental modal analysis is carried out by the hammering method. The spatial pipe model is modeled by the new method proposed in this paper, and the computation results are compared with the experimental results and those of the commercial finite software ANSYS Workbench. The results show the validity and the effectiveness of the new model. Finally, the effect of the fluid speed on the pipe system natural frequencies is simulated.