An active interface for rapid structural control

大多数自然生物在与环境相互作用时都表现出令人着迷的机械多功能性。在自然界中，刚度调谐是将刚性结构的承载功能与柔度和适应性相结合的有力工具。在棘皮动物中可以看到一个值得注意的刚度调整的例子，比如海参，在不到1秒的时间里，机械硬度可以变化10倍。人造结构的设计通常是为了满足特定的承载要求。为了增加其他功能，通常需要额外的组件；这增加了结构的总重量和成本，从而导致性能、效率和安全方面的限制。因此，在一个结构中嵌入传感、驱动和控制是非常可取的。受自然生物体中刚度调节的启发，近年来各种合成材料被开发出来用于结构主动控制。然而，在不破坏结构承载能力的情况下，以最小的功率要求在短时间内实现显著的刚度降低仍然是一些主要的挑战。在这项提议中，我们的目标是通过利用光电子学和纳米技术的最新进展来设计、制造和评估嵌入在热塑性层中的纳米结构互联金属网络来应对这些挑战。然后，该层将被用作常规多层结构中的有源界面。一旦激活，它将提供快速的结构控制和冲击保护能力。我们将使用实验和数值相结合的方法来研究该界面的电-热-机械响应。了解限制响应时间的主要物理障碍和控制该界面在恶劣电热载荷作用下的稳定性和失效的基本参数，将有助于我们在微观层面更好地设计该界面，以满足快速响应和低功耗的要求。这一新的认识将加速主动结构控制技术在未来多功能和智能结构中应用的技术准备水平。该技术在机器人、变形和可展开结构、主动减振和主动冲击防护等领域有着广泛的应用。作为一种潜在的代表性技术，我们的目标是将这种有源夹层应用于汽车夹层玻璃挡风玻璃。在挡风玻璃上应用这种透明的主动界面将有助于保护易受伤害的道路用户免受头部相关伤害，并被认为是朝着设计更有利于行人/骑自行车的车辆迈出的一步。为了推动这项技术的发展，萨里大学正在与NSG集团的成员Pilkington合作，NSG集团是世界上最大的建筑、汽车和工业玻璃行业的玻璃和玻璃产品制造商之一，以制造和测试这种用于汽车挡风玻璃的有源透明夹层。

Most natural organisms show fascinating mechanical versatility when interacting with their environments. Stiffness tuning in nature is used as a powerful tool to combine the load carrying functionality of rigid structures with compliance and adaptability. A remarkable example of stiffness tuning can be seen in echinoderms, such as sea cucumbers, where the mechanical stiffness can change by a factor of 10 in less than 1s. Human-made structures are normally designed to meet a specific load carrying requirement. To add other functionalities, additional components are often required; these increase the total weight and cost of the structure and consequently cause limitations in performance, efficiency and safety. Therefore, embedding sensing, actuation and control within a structure is highly desirable. Inspired by stiffness tuning in natural organisms, various synthetic materials have been developed in recent years for active structural control. However, achieving significant stiffness reduction in a short time frame with minimum power requirements but without undermining the load carrying capacity of the structure remain as some of main challenges.In this proposal, we aim to tackle these challenges by exploiting recent advances in optoelectronics and nanotechnology to design, manufacture and evaluate a nano-structured interconnected metallic network embedded in a thermoplastic layer. This layer will be then employed, as an active interface, in a conventional multi-layered structure. Upon activation, it will provide rapid structural control and impact protection capabilities. We will use a combined experimental and numerical approach to investigate the electro-thermo-mechanical response of this interface. Understanding the main physical obstacles that limit the response time and the fundamental parameters controlling the stability and the failure of this interface under harsh electro-thermal loading will help us to better engineer this interface at the micro level to meet the fast response and low power requirements.This new understanding will accelerate the technology readiness level of active structural control technology to be used in future multi-functional and smart structures. This technology has a wide range of application in robotics, morphing and deployable structures, active damping and active impact protection. As a potential representative technology, we aim to employ this active interlayer in laminated glass windscreens for automotive vehicles. Application of this transparent active interface in windscreens will help protect vulnerable road users against head-related injuries and is believed to be a step change toward designing more pedestrian/cyclist-friendly vehicles. To motivate the development of this technology, the University of Surrey is partnering with Pilkington, a member of the NSG group, which is one of the world's largest manufactures of glass and glazing products for architectural, automotive and technical glass sectors to manufacture and test this active transparent interlayer for application in automotive windscreens.