基于自适应压电分流阵列的智能超构材料板减振降噪特性研究

The band gap properties of metamaterials can be used to steer the propagation of elastic waves in structures, where vibration and noise can be controlled. The introducing of piezoelectric shunting arrays have made the adjustable band gap with less additional mass possible. However, limited by analog or passive shunting techniques, the bandwidths and attenuations within the bandgaps as well as its tunability are not good enough for possible applications. In this project, we are willing to apply the self-adaptive digital control into the design of piezoelectric shunting arrays in order to fabricate digital piezoelectric shunting units as well as the smart metamaterials with self-adjustable bandgaps. At the same time, modern control theories and techniques will be applied in order to cast off all the restraints that relate to analog electronic circuits. As a result, adaptive multi-resonant bandgaps with wider bandwidths and larger attenuations can be expected. Finally, Aiming at potential applications in vibration and noise control of plates within vehicle body, we will construct the smart metamaterial plate by attaching piezoelectric shunting arrays on it. The attenuation effects of vibrations as well as the structural acoustic radiation of it will be analyzed. The effects will also be used as the aim in the optimization of the topology, material parameters, as well as the control strategy of the digital shunting controllers.

超构材料的带隙特性可对弹性波的传播进行调控，从而实现振动与噪声的控制；而压电分流阵列的引入，为带隙的可调以及附加质量的降低提供了可能。然而，受模拟电路以及被动分流技术的制约，基于压电分流阵列超构材料的低频带隙带宽及衰减不足，可调性不够，难以得到应用。本项目拟将自适应数字控制引入压电分流阵列的设计中，采用传感/驱动或阻抗调节两种控制方式设计数字式压电分流控制器，继而构建智能超构材料板，实现带隙特性的自适应调节；同时，通过引入现代控制理论与技术，使压电分流阵列的设计摆脱原有的模拟电路的制约，在提高带隙性能的基础上，实现多模、宽带、主动可调的弹性波抑制；继而以车身壁板的振动和声辐射问题为背景，分析压电分流阵列的引入对基体板原有振动及声辐射特性的实际抑制效果，并以此为目标，对智能超构材料板的拓扑结构、材料参数以及自适应控制策略进行优化。

基于自适应智能超构材料具有适用带宽可调、减振降噪性能优异、智能化在线调控声波等特点，本项目提供了几种可实现主动型减振降噪的设计方法与研究思路，在航空航天，声学器件，汽车NVH，以及环境噪音治理上具有巨大的应用潜力。本项目从理论分析、数值模拟和实验验证等不同方面，对自适应智能超构材料进行了系统性的研究。通过等效参数，谐波平衡法以及有限元等数值分析方法深入探究了自适应智能超构材料的减振降噪物理机制以及影响因素，并且建立“电路-力学耦合模型”，来探究其作用的频率带宽以及动力学响应。而在实现自适应智能超构材料中，是通过微控制器来控制压电材料的输入电压，进而调控或者增强自适应智能超构材料的减振降噪特性。基于上述分析，本项目总结了自适应智能超构材料的调控声波新机制及其对弹性波的影响规律，进而构建了一系列新特性的声学器件，取得的代表性的成果包括：提出多模态谐振降噪的薄膜/板型智能声学超构材料，可对多个声波模态峰产生平均22 dB的声衰减；设计了具有反非线性的智能非线性智能超构材料梁，在小振幅激励下的非线性智能超构材料的振动衰减带宽是大振幅激励下的3倍，并且具有宽频减振带宽；另外还结合现代控制理论，利用驱动-双传感的方案，实现了前馈式-控制的智能压电超构单元，可对弹性波进行智能化调控；还实现了优异隐身性能的超构材料声学斗篷（Scilight 专题报道），其透射效率可达97.2%；另外设计了非对称PT压电超构材料梁，高声能回收超构材料，波模转换压电超构表面等一系列超常规的声学功能器件。这些成果不但丰富了声学领域的基础理论，还推动了声学器件以及减振降噪的技术发展，为自适应智能超构材料的进一步应用发展增添了新活力。