Active Control of the Fluid-Coupled Vibration of Thin-Walled Structures

管道、壳等薄壁结构易发生与流体有关的颤振、散度等动力失稳。为了稳定薄壁结构的流激振动，本文提出了一种主动控制方法。首先对悬挑管道的动态稳定性和主动控制进行了理论研究。为了控制悬挑管道的响应，利用附着在管道上的一对肌腱产生的扭矩推导出主动控制力。同时利用压电作动器产生转矩。利用伽辽金方法，结合最优调节器理论对该问题进行了求解。对不同工况下管道输送流体的响应进行了数值模拟。研究发现，在控制输入有限的情况下，采用肌腱机构和压电作动器的主动控制方法可以有效地稳定输送流体的管道。其次，采用直流伺服电机和压电作动器对理论结果进行验证。将最小阶状态观测器和数字最优调节器理论应用于个人计算机。此外，发现主动控制可以抑制壳体的流激振动。

The thin-walled structures such as pipes and shells are easy to become the dynamic instability connected with fluid, that is flutter and divergence. To stabilize the flow-induced vibration of the thin-walled structures, an active control method was proposed in this study.At first theoretical studies on the dynamic stability and active control of cantilevered pipes conveying fluid were conducted. In order to control the response of the cantilevered pipe, an active control force was derived by the torque produced by a pair of tendons attached to the pipe. And also piezoelectric actuators was used to generate the torque. The problem was solved by means of the Galerkin method, in conjunction with the optimal regulator theory. The numerical simulation of the response of the pipe conveying fluid was also carried out for various conditions. It was found that the active control method using the tendon mechanism and the piezoelectric actuator is effective to stabilize the pipe conveying fluid, even if the control input is limited.Next, the theoretical results were confirmed by the experiment in which DC servo motors and piezoelectric actuators were used. Also the minimum order state observer and the digital optimum regulator theory were used with personal computers.Furthermore, the flow-induced vibration of shells was found to be suppressed by the active control.