Multifunctional adhesive layers with crack-stop function and gradient sensing technology for structural health monitoring to be used as joining technology in CFRP light-weight structures

具有止裂功能和梯度传感技术的多功能粘合层用于结构健康监测，可用作 CFRP 轻质结构的连接技术

• 批准号: 401136681
• 负责人: Professor Dr. Andreas Dietzel
• 金额: --
• 依托单位: Institut für Mikrotechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/401136681?language=en
• 关键词: Multifunctional; adhesive; layers; crack; stop

The initial application pursued the goal of integrating a thin-film sensor system directly into highly stressed bondlines of composites and combining it with a crack-stop technology in order to improve the operational reliability of bonded composite structural components. In this context, function compliant sensor integration is of great importance, because the sensor technology must neither impair the adhesive bond nor the crack-stopping functionality. A lithographically produced smart inlay, made of a polyetherimide (PEI) substrate layer and a poly(vinylidene fluoride) PVDF top layer has been developed. This enabled to visualize a growing damage within the bondline by a strain gradient measurement. The PVDF simultaneously functions as crack stopper. Hence, integrated into a bondline, the smart inlay creates a multifunctional disbond arrest feature (MDAF). Regarding the MDAFs, core challenges could be solved. E.g., the surface quality of the new substrate could be adjusted to meet the requirements of the micro fabrication of thin-film sensors. Despite having confirmed the working principals of the Mulifunctional Bondline, there is further need for fundamental research, especially regarding the robustness of the sensors. The goals of the second funding period are developing a design methodology based on characteristic values to be established for functionally compliant multifunctional bondlines, improving the dynamic strength of the sensors and implementing scaling methods for large-area sensor integration. Complementing the first funding period, further investigations are carried out to generate experimental characteristic values. These characteristic values can then be used to evaluate and compare different variants of the Multifunctional Bondline. Alternative substrate materials and pre-treatment methods will be tested to improve the dynamic strength of the smart inlays. Furthermore, with screen printing, a new manufacturing process is investigated that allows the usage of stretchable conductive pastes to manufacture the required sensor structures. Due to this stretchability and the presumably more homogeneous stress distribution compared to the metallic sensor structures, an improved sensor dynamic strength can be expected. With the improved smart inlays, it is the aim to improve the damage detection algorithm to achieve robust damage detection and crack length prediction. To conclude the project, scaling methods for larger area components will be investigated. This part will look at how sensor structures can be interconnected such that large areas can be covered. In addition, piezoelectric energy harvesting concept are investigated to enable self-sustaining smart inlays. The scalability of the multifunctional crack-arrest technology is tested by an omega-stringer to skin adhesive bond that is typical for light-weight design.

最初的应用追求的目标是将薄膜传感器系统直接集成到复合材料的高应力粘合层中，并将其与止裂技术相结合，以提高粘合复合材料结构部件的操作可靠性。在这种情况下，符合功能的传感器集成非常重要，因为传感器技术必须既不损害粘合剂粘合，也不损害止裂功能。已经开发了由聚醚酰亚胺（PEI）基底层和聚（偏氟乙烯）PVDF顶层制成的光刻生产的智能嵌体。这使得能够通过应变梯度测量可视化胶层内的不断增长的损伤。PVDF同时起到止裂剂的作用。因此，集成到粘合层中，智能嵌体创建多功能脱粘制动功能（MIBR）。关于多边发展援助框架，核心挑战是可以解决的。例如，在一个示例中，新基片的表面质量可以调节，以满足薄膜传感器微细加工的要求。尽管已经确认了多功能Bondline的工作原理，但仍需要进一步的基础研究，特别是关于传感器的鲁棒性。第二个供资期的目标是开发一种基于特性值的设计方法，以建立功能兼容的多功能粘合层，提高传感器的动态强度，并实施大面积传感器集成的缩放方法。作为对第一个供资期的补充，还进行了进一步的调查，以产生实验特征值。这些特征值可用于评估和比较多功能粘合线的不同变体。将测试替代基底材料和预处理方法，以提高智能嵌体的动态强度。此外，与丝网印刷，一个新的制造工艺进行了研究，允许使用可拉伸的导电膏来制造所需的传感器结构。由于这种可拉伸性和与金属传感器结构相比可能更均匀的应力分布，可以预期改进的传感器动态强度。利用改进的智能嵌体，对损伤检测算法进行改进，实现稳健的损伤检测和裂纹长度预测。为了结束该项目，将研究大面积组件的缩放方法。本部分将研究传感器结构如何互连，以便覆盖大面积。此外，压电能量收集的概念进行了研究，使自我维持的智能嵌体。多功能止裂技术的可扩展性是通过欧米伽纵梁与蒙皮的粘接来测试的，这是典型的轻量化设计。