Developing of a repair method for carbon fibre reinforced plastics by using thermally activated oxide semiconductors

基于碳纤维增强的纤维塑料(FRP)在高科技应用中的使用正在稳步增长，这导致了对CFRP构件合适的修复概念的研究的需求和日益增长的需要。本项目的主要目的是为开发一种新的基于热固性材料的CFRP结构构件在高科技应用中的修复方法提供科学依据。建议从损伤区域完全去除现有的基体，插入符合载荷的更新的纺织增强层，最后用合适的基体浸渍和加固增强体。研究目的是研究不同的无机氧化物对基于主要使用的环氧树脂的热固性基质体系的局部降解效率。选择的标准是氧化物半导体的带隙，因为它显著影响激活能和相关的工作温度。结合催化剂所需的活化能及其注入修复区热固性基质的局部去除，考察了基质降解的具体控制。此外，还必须分析金属氧化物对碳纤维的力学性能(纤维降解、弹性模量、拉伸强度、表面能)以及完整和降解基质之间的过渡区的影响。后者对于新的基质材料的附着力尤为重要。为了重建复合材料的承载能力，对在原有结构破坏情况下，新的重叠纺织增强层的重建进行了模拟辅助分析。最后，修复后的CFRP结构通过浸渍、用相同真空注入的热固性基材加固和随后的硬化，在更新的加固区域形成复合材料，恢复修复后的CFRP结构的初始承载能力。这些研究最初是在矩形和圆形损伤试件上进行的。

The use of fibre plastic (FRP) based on carbon fibre reinforcements in high-tech applications is steadily growing, resulting in the demand and the increasing need for research on appropriate repair concepts for CFRP components.The main objective of this project is to create a scientific basis for the development of a new repair method for CFRP structural components based on thermosets in high-tech applications. It is proposed to completely remove the existing matrix from the damaged region, insert load conforming renewed textile reinforcement layers and then finally to impregnate and consolidate the reinforcements with a suitable matrix. Thereby, the initial load bearing capacity is intended to be achieved without any additional thickening of the original structure.The research objective is to study the efficiency of different inorganic oxides for the local degradation of thermosetting matrix systems based on the predominantly used epoxy resins. A selection criterion is the band gap of the oxide semiconductor, because it significantly affects the activation energy and the associated operating temperature. In connection with the required activation energy of the catalyst and its injection into the local removal of the thermosetting matrix in the repair area, the specific control of matrix degradation is examined. Furthermore, the influence of the metallic oxides on the mechanical properties of carbon fibres (fibre degradation, modulus of elasticity, tensile strength, surfaces energy) and the transition zone between the intact and degraded matrix has to be analyzed. The latter is particularly important for the adhesion of the new matrix material. The possible role of the remaining catalyst materials in reestablished composite and their mechanical properties have also to be explored.For the reestablishment of the load bearing capacity of the composite, a simulation aided analysis is intended for the reconstruction of the new overlapping textile reinforcement layers in the damage of the original structure. Finally, the initial loading bearing capacity of the repaired CFRP structure is restored by the composite formation in the renewed established reinforcing area through impregnation, consolidation with the same vacuum infused thermoset matrix material and subsequent hardening. These studies are initially carried out on rectangular and circular damaged samples.