具有频率幅值自适应性的智能吸振系统研究

In the supersonic speed trials, the vibration of pipeline system in wind tunnel lowers the quality of flow field, which interferences the model test precision seriously. Therefore, to promote the pipeline vibration noise control technology is the urgent demand in the research and development of supersonic wind tunnel. Because of the changeable source characteristics and complex vibration modal of wind tunnel piping system, developing the smart magnetorheological elastomer (MRE) absorber, which has the merits of wide frequency modulation range, fast response and advantageous distributed control, is the effective measure to solve the problems. However, in order to overcome the difficulty of unidirectional adjustment of magneto-induced modulus of existing MRE, and to broaden the frequency range of MRE absorber, preparing the novel MRE with bidirectional magnetic modulus by mixed permalloy powders with rubidium iron boron particles is proposed. The techniques such as polyaniline coating are employed to reduce the Payne effect and damping coefficient of the MRE, then the system of characterization and modeling is set up for the further performance study of the material. On the basis of material research, improving the design method, optimizing the structure and parameters, and realizing the two-way magnetic stiffness adjustment of the intelligent MRE absorber are the second content of this project. Finally, the broadband wide and time-varying vibration suppression experiments of piping system are implemented by the fuzzy adaptive control. This study is not only a bold attempt of applying the intelligent material to wind tunnel piping vibration system, but also a multi-disciplinary crossed research of precision machinery, intelligent control and vibration theory, which has the important academic value and great prospect of engineering application.

在跨超声速试验中，风洞管路的振动降低流场品质，严重干扰模型测试准确度。提升管路振动噪控制技术是跨超声速风洞研发的迫切需求。针对风洞管路多变的振源特性和复杂的振动模态，研发具有调频范围宽、响应速度快、便于分布式控制的磁流变弹性体（MRE）智能吸振器是解决该难题的有效手段。为了克服MRE材料只能正向调节磁致模量的缺点，拓宽智能吸振器的调频范围，申请人提出利用坡莫合金与铷铁硼粉末混合制备具有双向磁致模量的MRE，通过聚苯胺包覆等手段降低佩恩效应和阻尼系数，并对材料进行表征和建模；在此基础上，改进智能吸振器设计方法，优化结构和参数，实现双向磁控刚度实时调节；搭建实时控制系统，设计模糊自适应控制策略，进行控制仿真及实验，完成对管路系统的宽频宽幅时变振动抑制。该研究不仅是智能材料在风洞管路振动控制的大胆尝试，也是精密机械、智能控制和振动理论的多学科交叉，具有重要的学术价值和巨大的工程应用前景。

风洞管路的振动对模型测试精度和设备安全造成不可忽视的负面影响，管路振动是先进风洞系统亟待攻克的难题。风洞管道的振动抑制通常采用动力吸振器，由于管道振动频率会随着测试工况产生明显变化，而传统吸振器固有频率无法适应激励频率的变化，只能解决定频振动的抑制问题。基于磁流变弹性体（Magnetorheological elastomers，MRE）的智能吸振器具有可调范围宽、响应速度快等优势，成为研究热点。受软磁MRE的单向磁控模量的限制，大多数MRE吸振器的固有频率只能向高频调谐，无法解决风洞管道低于吸振器零场固有频率的振动问题。基于此，本项目采用硬磁颗粒研发了具有双向磁控模量的硬磁颗粒的MRE，设计加工了双向磁控调谐的磁流变吸振器，通过模糊控制算法调控追踪激励频率，实现了吸振器的双向自适应调谐吸振。本项目研究了MRE在不同荷载和磁场激励下的力学特性，借助工业CT技术对MRE的微观结构进行了三维重构，并采用多物理场仿真软件对MRE的力磁耦合机制进行了分析，建立了MRE在振动激励下的力学模型，为吸振器的设计优化奠定了基础。基于流变仪搭建了MRE的响应时间测试系统，为MRE的材料优化和减振器件的控制策略提供了理论依据。在器件设计优化方面，提出了联合仿真设计优化理论，实现了器件快速响应、高磁控性能、低能耗的多目标优化。项目分析测试了国内某风洞系统管道的振动特性，并以此为依据，设计加工了一款面向管道多维振动的四振子对称结构吸振器，其反向和正向磁控移频分别为3Hz和11Hz。最后，本项目提出了基于被动模型传递率的模糊控制算法，在搭建的管道振动测试系统上进行了实验验证。该模糊控制算法在Simulink中的仿真结果表明，管道吸振衰减可达80%以上，实现了对管路系统振动的显著抑制。本项目不仅是智能材料在风洞管路振动控制中的大胆尝试，也是精密机械、智能控制和振动理论的多学科交叉，在磁流变材料、减振器件和自适应控制理论等方面取得的研究成果为提升风洞系统的测试性能提供了重要的技术支撑。