【作者】 王成；

【导师】 徐赵东；

【作者基本信息】 东南大学 ， 土木工程， 2017， 硕士

【摘要】 斜拉索作为大跨斜拉桥的主要受力构件,由于柔度大、质量小、阻尼小等特点,极易在外部激励下引发大幅振动,造成极大的安全隐患。如何有效地控制斜拉索的振动,减小大跨桥梁疲劳损伤或破坏具有重要意义。磁流变阻尼器具有响应快、可控性好、可调范围宽、所需外部能源少、适应性强等优点,使得其成为理想的斜拉索振动控制方法。作为它的一种形式,单出杆磁流变阻尼器因行程大、不易渗漏、安装空间小等优点,而适于斜拉索的风振控制。目前,国内外专家学者对磁流变阻尼器及其对斜拉索振动控制方面做了较多理论和试验研究,取得了一定的成果,但在单出杆磁流变阻尼器的体积补偿、磁流变阻尼器的研制和性能试验、磁流变阻尼器的力学模型及其逆控制电流、斜拉索磁流变阻尼半主动控制算法等方面仍存在一些需要解决和完善的问题。本文从单出杆磁流变阻尼器单体入手,采用课题组制备的CB22型磁流变液,设计制作了一台单出杆磁流变阻尼器,对其进行了相关力学性能试验和参数模型识别,提出了基于最优等效模型的斜拉索半主动控制算法,分析了斜拉索-磁流变阻尼器系统风振半主动控制效果。本文的主要研究内容和有关结论如下:(1)设计了一种隔离式体积补偿装置,可以有效解决单出杆磁流变阻尼器工作腔内磁流变液外渗至体积补偿腔或者体积补偿腔内空气跑到阻尼器工作腔的问题,并通过单出杆磁流变的力学性能试验结果验证了其有效性。(2)采用课题组研制的磁流变液,基于统一优化设计的思想,设计制作了一台阻尼力1.5KN左右的单出杆磁流变阻尼器。(3)对研制的单出杆磁流变阻尼器进行力学性能试验,分析了电流、激励频率、位移幅值与阻尼力的关系。在性能试验结果的基础上识别了阻尼器修正的Sigmoid模型,并将识别的参数模型模拟值与试验结果对比,结果表明,识别的模型具有较高精度。为追踪半主动振动控制中所需的实时控制力,在控制点实测响应的基础上,通过一种迭代方法来逆推参数模型的控制电流,以使得磁流变阻尼器的实际出力逼近所需控制力,并用随机信号验证了该方法的有效性和适应性。(4)提出了基于最优等效模型的斜拉索半主动控制算法,该算法在LQR主动控制的基础上考虑磁流变阻尼器阻尼力的方向性优化了权系数,并结合一种很好追踪LQR控制力的等效模型。对加入磁流变阻尼器的斜拉索进行了随机风振下半主动控制的数值仿真研究,结果显示,半主动控制减振效果显著且优于最优被动控制。更多还原

【Abstract】 As the main force component of the long-span cable-stayed bridge,the cable-stayed cable is characterized by large flexibility,low quality and small damping.It can easily cause great vibration under external excitation,resulting in great security risk.MR dampers have the advantages of fast response,good controllability,wide adjustable range,low energy consumption and strong adaptability,which make them ideal vibration control technique for cable-stayed cable.One form of them,single-rod MR damper is more popular because of its large movement of piston,good sealing,requires short space for installation and so on,and it is much more considerable by scientific researchers.So far,domestic and foreign scholars have made many theoretical and experimental researches on(single-rod)MR damper and its vibration control of cable-stayed cable,they achieved some goals,but there are still some problems to be solved,such as the volumetric compensation of single-rod MR damper,the development and performance test of the MR damper,describing reverse control current of the MR damper mechanical model,the semi-active control algorithm of stay cable with the MR damper,etc.Starting from the single-rod MR damper,this paper used the CB22 MR fluid,which is developed by the research group.A single-rod MR damper,whose volume compensation is isolated,is designed and manufacture.The mechanical properties of damper are tested,and the parameters of damper are identified.Then the semi-active control algorithm based on optimal equivalent model for stay cable is proposed in this thesis,and the semi-active control effect of stay cable with MR damper was analyzed under the wind vibration.The main contents of this paper and the relevant conclusions are as follows:(1)One volume compensation device,whose volume compensation was isolated,is redesigned,and improved.It could effectively solve the problem that MR fluid in the working chamber would infiltrate to the volume compensation chamber or the air in the volume compensation chamber would flow into the working chamber.And the validity is verified by the results of single-rod MR damper’s mechanical performance test.(2)Based on the idea of unified optimized design,a single-rod MR damper,and the damping force is about 1.5KN,designed and fabricated.The type of MR fluid used in the damper is developed by the research group.(3)The effects of current,excitation frequency and displacement amplitude on damping force are analyzed.Based on the results of the performance test,the modified Sigmoid model of damper is identified.Compared with experimental results,the identified parameters of model show high accuracy.In order to track the real-time control force required in the semi-active vibration control,the control current of the parametric model is reversed by an iterative method on the basis of the control point’s measured response,so that the actual output force of the MR damper would approximate the required control force.Finally,the validity and adaptability of the iterative method are verified by the random signals.(4)The semi-active control algorithm based on optimal equivalent model for stay cable is proposed in this thesis.Considering the direction of MR damper’s damping force,the algorithm optimizes the weight coefficient of LQR active control,and is combined with an equivalent model for tracking LQR control.Under the wind vibration,the semi-active control effect of stay cable with MR damper is numerically simulated,and the results show that the semi-active control effect is significant and better than the optimal passive control.更多还原