Study of electromechanical metamaterial systems

机电耦合智能压电系统具有结构紧凑、灵敏度高、寿命长、能对环境刺激作出真实的响应等优点，近年来受到工程界的广泛关注。压电智能结构由于具有传统结构所不能比拟的上级功能，其应用领域十分广泛。探索、开发和利用智能技术新产品的竞赛一直在进行，这为相关行业提供了新的机遇，但也为保持竞争力带来了挑战。制造技术的进步使得能够开发新型智能结构，其以高密度嵌入传感、致动和通信。这种嵌入可以如此紧密，以至于结构和材料之间的区别变得模糊，因此这些智能结构可以等同于新的智能材料。这些进步也使得设计智能系统的详细局部结构成为可能。本项目的目标是开发新的集成压电智能材料系统，该系统由周期性排列的特殊设计的材料单元组成。智能材料的机电性能将由材料单元的性能和材料的周期性结构决定。与传统复合材料不同的是，传统复合材料的所需性能，如更高的刚度和强度，来自于利用各个成分的最佳性能，新型智能材料的机电性能不仅由材料组成来定制，而且更重要的是，由材料单元的局部结构的详细几何设计来定制。** 理论研究将集中在（i）能够描述所设计的局部材料单元的复杂机电行为的机械模型的开发，（ii）优化局部材料单元的设计以实现先进或奇异的机电性能。（超材料），（iii）将局部单元集成到周期性结构中以形成期望的智能材料，（iv）表征和评估新型智能材料的机电性能，以及（v）评估智能材料的失效条件。实验研究将基于传统制造技术和/或增材制造来构建和评估新型智能材料的性能。在短期内，目前的研究将提供新的思路和指导，如何设计先进的压电智能材料与传统的新性能。从长远来看，目前的研究成果可以用于下一代可编程智能材料的设计，这些材料可以很容易地控制和通信。

The development of electromechanically coupled smart piezoelectric systems, which can respond to environment stimuli in real time and are compact, sensitive and durable has received considerable attention from research and industrial communities in engineering. Because of their advanced functionalities superior to the convectional structures the applications of these smart piezoelectric structures are widely spread into diverse areas. The race is always on to explore, develop and exploit new products of smart technology, which provides new opportunities for the associated industries, but also impose challenges for keeping to be competitive. The advances in manufacturing techniques have enabled the development of new classes of smart structures that embed sensing, actuation and communication at high densities. This embedding can be so tight that the distinction between structure and materials blur so these smart structures can be considered equivalently as new smart materials. These advances also make it possible to design the detailed local structures of the smart systems.******It is the objective of the current project to develop new integrated piezoelectric smart material systems, which consist of periodically arranged specially designed material cells. The electromechanical properties of the smart material will be dominated by both the property of the material cells and also the periodic structure of the material. Different from traditional composite materials for which the desired properties, such as higher stiffness and strength, come from utilizing the best' properties of the individual constituents, the electromechanical properties of the new smart materials are tailored not only by material composition but also, and more importantly, by the detailed geometrical design of the local structure of the material cells. ******The theoretical study will be focused on (i) the development of mechanical models capable of describing the complicated electromechanical behaviour of the designed local material cells, (ii) the design of local material cell optimized to achieve advanced or exotic electromechanical properties (metamaterials), (iii) the integration of the local cells into periodic structures to form the desired smart materials, (iv) the characterization and evaluation of the electromechanical properties of the new smart materials, and (v) the evaluation of failure conditions of the smart materials. The experimental study will be conducted to build and evaluate the properties of the new smart materials based on traditional manufacturing techniques and/or additive manufacturing. In the short term, the current research will provide new ideas and guidelines on how to design advanced piezoelectric smart materials with new properties not available conventionally. In the long term, the outcome of the current research could be used in the design of the next generation programmable smart materials, which can be easily controlled and communicated with.**