Advanced Manufacturing of Intelligent Structures

我们一直认为，2020年将是一个完美的世界，所有复杂的工程结构，如飞机、风力涡轮机叶片、桥梁、汽车，都将检测并自主抵消外部负载（重量、扭矩、风）以及内部异常（缺陷、故障），以确保其整个使用寿命期间的安全性和经济性。是什么阻碍了今天的工程结构变得智能——即感知和处理周围环境的变化，并根据这种变化进行调整？答案是，今天的结构要么是：坚固，适应性强，要么是轻量级的。可重构的飞机结构需要在一种材料中实现所有这三个特性，这是我们设计工程师几十年来面临的挑战。拥有上述特征的智能结构需要智能材料——其物理特性可以通过外部刺激（如应力、湿度、电场和磁场、光、温度和化学物质）改变的材料——以及具有内置反馈回路的控制系统来实现自主性。该研究计划提出通过将高强度复合材料的先进制造与智能材料的增材制造（AM）相结合来解决这一冲突，以创建可重构飞机的控制面。AM的灵感来自大自然的生长和发展，它是智能结构中最相关的制造工具，提供有机和高效的复杂几何形状，这是高效鸟类飞行的特征，我们的灵感来自大自然。今天的飞机、汽车、风力涡轮机叶片都是由纤维增强聚合物（FRP）制造的，集成了智能材料，用于形状适应，在FRP的自动化纤维放置过程中，将导致相当大的重量和空间节省。在复合材料结构的生产和使用过程中，利用嵌入式传感器进行结构健康监测将有助于有效和及时的维修，从而延长产品的生命周期。此外，三维（3D）打印的电气连接将减少电线杂乱。具有闭环反馈回路的控制系统是实现结构重构的必要条件。但是，与传统的机械刚体替代品相比，今天的智能材料效率低下且不可靠，因此，不满足飞机安全认证要求。我的研究项目旨在开发这些智能材料，并改善它们与高强度材料的兼容性，用于智能结构的设计、优化和制造。在这个项目中获得的技术诀窍可以直接应用于交通、能源生产和空间的智能结构；以及其他结构和功能复合部件，特别是个性化设备，如假肢，康复辅助设备，外骨骼和个人运动设备。

We had always imagined 2020 to be a perfect world where all complex engineering structures like planes, wind turbine blades, bridges, cars would detect and autonomously counteract external loads (weight, torque, winds) as well as internal anomalies (defects, failures) to ensure safety and economy during their entire service-life. What is it that prohibits the engineering structures of today from being intelligent - i.e. to sense and process a change in their surroundings and adapt themselves in accordance to this change? The answer is that today's structures are either: strong, adaptable, or lightweight. Reconfigurable aircraft structures require achieving all the three characteristics in a single material, which is the challenge we design engineers are facing for decades. Intelligent structures possessing the above characteristics mandate smart materials - materials whose physical properties can be altered by external stimuli like stress, moisture, electric and magnetic fields, light, temperature, and chemical substances - and a control system with an inbuilt feedback loop for autonomy. This research program proposes to resolve this conflict by merging advanced manufacturing of high-strength composites with additive manufacturing (AM) of smart materials to create control surfaces for reconfigurable aircraft. Inspired from the nature's growth and development, AM serves as the most pertinent fabrication tool for intelligent structures delivering organic and efficient complex geometries, which are a characteristic of an efficient bird flight, our inspiration from nature. As the airplanes, cars, wind turbine blades today are being manufactured from fiber reinforced polymer (FRP), integrating smart materials, for shape adaptation, during automated fiber placement of FRP would result in considerable weight and space savings. Structural health monitoring with embedded sensors during the production and service of the composite structures will help in efficient and timely repair and thus, enhanced product life cycle. Additionally, three-dimensionally (3D) printed electrical connections, would decrease the wire clutter. Control systems with closed feedback loop are essential to program the reconfiguration into the structures. But, the smart materials of today are inefficient and unreliable compared to their conventional mechanical rigid body alternatives and hence, do not satisfy the aircraft accreditation requirements for safety. My research program aims at developing these smart materials and improving their compatibility with the high strength materials for the design, optimization, and fabrication of intelligent structures. The know-how gained in this project can be directly applied to build intelligent structures for transportation, energy generation, and space; and other structural and functional composite components, especially in personalized equipment like prosthesis, rehabilitation-aid, exoskeletons, and sports equipment towards individuals.