Hornig Andreas, Winkler Anja, Bauerfeind Eric, Gude Maik, Modler Niels
Institute of Lightweight Engineering and Polymer Technology (ILK), Technische Universität Dresden, Holbeinstraße 3, 01307 Dresden, Germany.
AB Elektronik Sachsen GmbH, Salzstraße 3, 01774 Klingenberg, Germany.
Polymers (Basel). 2021 Nov 13;13(22):3926. doi: 10.3390/polym13223926.
Fiber reinforced composites combine low density with high specific mechanical properties and thus became indispensable for today's lightweight applications. In particular, carbon fibre reinforced plastic (CFRP) is broadly used for aerospace components. However, damage and failure behaviour, especially for complex fibre reinforcement set-ups and under impact loading conditions, are still not fully understood yet. Therefore, relatively large margins of safety are currently used for designing high-performance materials and structures. Technologies to functionalise the materials enabling the monitoring of the structures and thus avoiding critical conditions are considered to be key to overcoming these drawbacks. For this, sensors and actuators are bonded to the surface of the composite structures or are integrated into the composite lay-up. In case of integration, the impact on the mechanical properties of the composite materials needs to be understood in detail. Additional elements may disturb the composite structure, impeding the direct connection of the composite layers and implying the risk of reducing the interlaminar integrity by means of a lower delamination resistance. In the presented study, the possibility of adjusting the interface between the integrated actuator and sensor layers to the composite layers is investigated. Different polymer layer combinations integrated into carbon fibre reinforced composite layups are compared with respect to their interlaminar critical energy release rates GIc and GIIc. A standard aerospace unidirectionally reinforced (UD) CFRP prepreg material was used as reference material configuration. The investigations show that it is possible to enhance the mechanical properties, especially the interlaminar energy release rate by using multilayered sensor-actuator layers with Polyimide (PI) outer layers and layers with low shear stiffness in between.
纤维增强复合材料兼具低密度和高比机械性能，因此在当今的轻量化应用中不可或缺。特别是，碳纤维增强塑料（CFRP）被广泛用于航空航天部件。然而，损伤和失效行为，尤其是对于复杂的纤维增强结构以及在冲击载荷条件下，仍未被完全理解。因此，目前在设计高性能材料和结构时使用了相对较大的安全裕度。使材料功能化以实现对结构的监测从而避免临界状态的技术被认为是克服这些缺点的关键。为此，传感器和致动器被粘结到复合材料结构的表面或集成到复合材料铺层中。在集成的情况下，需要详细了解对复合材料机械性能的影响。额外的元件可能会干扰复合材料结构，阻碍复合材料层之间的直接连接，并意味着存在因较低的抗分层性而降低层间完整性的风险。在本研究中，研究了调整集成致动器层和传感器层与复合材料层之间界面的可能性。将集成到碳纤维增强复合材料铺层中的不同聚合物层组合在层间临界能量释放率GIc和GIIc方面进行了比较。一种标准的航空航天单向增强（UD）CFRP预浸料材料被用作参考材料配置。研究表明，通过使用具有聚酰亚胺（PI）外层和中间具有低剪切刚度层的多层传感器 - 致动器层，可以提高机械性能，特别是层间能量释放率。
