定常和非定常流速下输流管非线性动态响应的实验研究

The pipes conveying fluid are often used in aeronautical, astronautical, nuclear and mechanical fields. An experimental platform will be studied and designed in this research project. Based on this experimental platform, the experimental method will be used to study the nonlinear vibrations of the pipes conveying fluid with two ends supported and the cantilevered supporting conditions under combined forcing and parametric excitations. The instable regions of the forced and parametric resonances for different parameters will be studied in depth. The experimental data can be analyzed by the curve fitting method to verify the results obtained by the analytical methods. The nonlinear dynamics, bifurcations and chaos of the pipes conveying fluid under combined external parametric and excitations will be theoretically and experimentally investigated. The combination of the experimental and analytical methods will be used to study the nonlinear dynamic responses and the fluid-structure interaction of the pipes conveying fluid with two ends supported and the cantilevered supporting conditions. This research will provide the experimental support for the further studies of the nonlinear dynamics.

输流管是航空航天、核工程和机械工程等领域中常用装置和结构。本项目研制输流管系统振动实验台，用实验方法研究强迫激励和参数激励作用下悬臂和两端支承输流管的振动特性，探求失稳区域随参数变化的机理。利用实验拟合方法，识别边界条件参数及非线性参数，揭示其作用机理。利用理论和实验方法研究外激励和参数激励联合作用下输流管的非线性动力学响应。利用实验结果与理论结果相互验证的方法研究两端支承以及悬臂支承两类输流管流-固耦合动力学特性，为非线性动力学的发展提供实验支持。

输流管在航空宇航工程、核工业、石油能源工业、海洋工程、化学工业等诸多现代工业领域内的应用越来越广泛。研究结果表明，当输流管道系统在某些条件下工作时，管道可能发生剧烈振动，这是由于流体作用力、管道弹性变形和外激励作用相互耦合作用而产生的复杂动力学现象。当振动的幅值达到一定大小并且振动持续发生时，输流管道将会因振动导致疲劳而产生裂纹，严重时还会引起装备的损坏，酿成灾难性事故。.课题组有关定常和非定常流速下输流管非线性动态响应的理论和实验研究工作取得了重要进展，发表SCI收录国际期刊论文15篇，主要进展集中在以下几个方面：(1)首次应用能量相位法研究了带有简谐外激励的悬臂输流管在脉动内流作用下的多脉冲混沌动力学；(2)深入研究了主参数共振-1:3内共振-1/2亚谐共振情况下，参数激励和外激励共同作用下竖直悬臂输流管的非线性共振响应、模态相互作用、多时间周期和混沌振动，研究了带有流体圆柱薄壳的非线性自由振动问题；(3)深刻揭示了横向载荷和参数激励下四边简支压电复合材料层合矩形板的混沌振动，研究了具有纳米多孔金属泡沫的功能梯度纳米壳的自由振动和屈曲问题，发现了一种广泛存在的轴向运动功能梯度材料金属矩形板的内共振现象；(4)研究了在谐波激励作用下旋转弹性薄圆柱壳的非线性强迫振动，和在气动力作用下变截面预扭高速旋转叶片的非线性振动和内共振问题；(5)搭建了输流管道在脉动内流作用下振动的实验平台，实验研究了悬臂输流管道的振动问题。

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