FRP embedded micro-sensors on multifunctional substrates for curing process control

开发用于轻质结构的创新高性能纤维增强塑料的一个重要挑战是使用嵌入式传感器对新生材料结构进行本地监控，以进一步减轻纤维复合材料结构的重量。人们非常需要用于在线监测纤维复合材料的应变和固化行为的新型传感器，它们对部件的尺寸稳定性、机械和物理特性以及使用寿命产生巨大影响。此外，借助仍然集成在材料中的传感器，可以避免或在早期检测到因过度负载而造成的材料损坏，从而可以更有针对性并更有效地进行支撑结构的维护。集成传感器的先决条件是复合材料的机械性能不会减弱。在第一种方法中，将以这样的方式选择传感器的材料、微加工工艺和设计，使得最初引入的“异物”几乎完全从材料化合物中消失，并且传感器系统不再机械地干扰结构。除此之外，当复合材料的机械性能甚至可以通过传感器嵌入来改善时，这将是令人着迷的。因此，在第二种方法中，该研究项目旨在开发基于非常薄的聚合物薄膜的集成传感器，甚至可以增强环氧基复合材料的冲击强度。无定形热塑性塑料可能是已用于增韧的候选材料。通过在薄箔上制作并随后集成到复合材料中的温度、阻抗和应变微型传感器，可以从材料的内部状态获得信息，这些信息可以作为生产过程中的控制数据。基于传感器的本地材料状态监控将有助于优化生产流程、缩短存储时间并提供完善的质量保证。

An important challenge for the development of innovative highperformance fiber reinforced plastics for light-weight constructions is the local monitoring of the nascent material structure using embedded sensors to allow further reducing the weight of fiber composite structures. Novel sensors for on-line monitoring of strains and of the curing behavior of fiber composite materials are highly desired and can have an enormous influence on the dimensional stability, the mechanical and physical characteristics, and the service life of a component. Furthermore, material damage resulting from excessiveloads could with the aid of sensors remaining integrated in the material be avoided or detected at an early stage so that the maintenance of the support structures can be more targeted and carried out more efficiently. A prerequisite for integrated sensors is that the compound material is not mechanically weakened. In a first approach, the materials, the microfabrication processes and the design of the sensors will be chosen in such a way that the initially introduced "foreign body" disappears almost completely from the material compound and the sensor system mechanically no longer disturbs the structure. Beyond that, it would be fascinating when the composite mechanical properties could even improve by the sensor embedding. In a second approach, this research project thereforeaims at the development of integrated sensors based on very thin polymer films that can even enhance the impact strength of the epoxy based composite. Amorphous thermoplastics are possible candidates being already in use for toughening. By means of micro sensors for temperature, impedance, and strain that are produced on thin foilsand subsequently integrated into the composite material, information can be obtained from the internal state of the material which can serve as control data during production. The sensor-based monitoring of local material state will allow optimization of the production processes, shortening of storage times and a sophisticated qualityassurance.