Non-Destructive Impact Damage Detection on Carbon Fiber Reinforced PlasticsIDD-Metro within BRAGECRIM

使用轻质碳纤维增强塑料(CFRP)减轻产品重量是该行业节约能源、面对国际气候目标和不断增加的能源成本的助推器。CFRP具有高比刚度和高强度的特点，这使其成为航空工业、风力涡轮机、汽车工业甚至消费品工业等轻量化应用的理想选择。事实上，最近已经推出了新的电动汽车，考虑到在支撑结构中使用了大量的CFRP，从而减轻了重量并增强了驾驶动力。随着碳纤维复合材料的使用从小批量生产扩展到大规模生产，预计未来几年碳纤维复合材料的需求将会增长。必须在整个产品生命周期中确保CFRP产品的经济可行性。因此，必须确保长期运行的可靠性和经济的维修过程。飞机和航空航天工业的既定概念基于人工过程，通常需要更换损坏的部件。碳纤维增强塑料产品的大规模生产需要经济可行和高效的维修工艺。因此，需要无损、可靠、高效、自动化的测量技术来适应材料、构件和维修车间的具体要求。便携式无损检测方法的发展势在必行，这种方法能够可靠地、全面地检测缺陷。热成像技术非常适合于碳纤维复合材料缺陷的无损检测。热像仪是便携的，覆盖面积大，而且省时。热像仪是基于2D图像的。这些图像包含样本的不同层的叠加(深度信息)。但是，无法直接获取元件上缺陷的绝对位置和大小及其深度信息。该项目的目标是设计、开发和建立一个系统，以可靠地检测CFRP组件中的冲击损伤及其各自的属性(尺寸、形状、位置和深度)，从而在车间环境中实现可靠的修复过程。这一目标将通过增强热成像来检测碳纤维增强塑料中缺陷的3D特性来实现。对不同冲击缺陷的CFRP试件进行热像分析、剪切成像和CT分析。根据CT结果，考虑到缺陷的深度和几何形状以及损伤的严重程度等特性，将绘制缺陷分类。将上述测量技术的结果融合在一起，将创建一个评估模型。该模型将被集成到演示器中并进行验证。该项目的其他好处是热像仪和CT的测量策略，以更好地量化CFRP损伤。结果将提高碳纤维增强塑料的质量保证，并使可靠的维修过程成为可能。该模型可以推广到其他材料和缺陷。

The reduction of weight of products using lightweight carbon-fibre-reinforced plastics (CFRP) is an enabler for the industry to save energy and face the international climate objectives and increasing energy costs. CFRP are characterized by a high specific stiffness and strength, which make them ideal for lightweight applications in e.g. aviation industry, wind turbines, automotive industry and even consumer goods industry. In fact, new electric vehicles have been introduced recently considering a significant amount of CFRP in the support structure, thus reducing weight and enhancing driving dynamics. The demand of CFRP is expected to grow in the coming years, since the use of CFRP expands from small batch production to mass production. The economic feasibility of CFRP products must be assured throughout the whole product life cycle. Therefore, the long term operational reliability and economic repair processes must be assured. The established concepts from aircraft and aerospace industry base upon manual processes and in general demand a replacement of damaged parts. A mass production of CFRP products requires economically feasible and efficient repair processes. Therefore, non-destructive, reliable, efficient and automated measurement technology is required to fit the material, component and repair work shop specific requirements. The development of portable and non-destructive testing methods, which reliably and holistically detect defects, is inevitable. Thermography is well suited for the non-destructive detection of defects in CFRP. Thermography systems are portable, cover large areas and are time efficient. The thermography is based on 2D images. These images contain an overlay of the different layers of the sample (depth information). But, the absolute position and size of the defect on the component and its depth information are not directly accessible. The objective of this project is to design, develop and setup a system to reliably detect impact damages with their respective properties (size, shape, position and depth) in CFRP components that enables a reliable repair process in the workshop environment. This goal will be achieved by enhancing the thermography to detect those 3D properties of defects in carbon fiber-reinforced plastics. CFRP samples with different impact defects will be studied with thermography, shearography and CT. From the CT results, a defect classification will be drawn, considering properties like the depth and geometry of the defects and the severity of the damage. Fusing the results from aforementioned measuring techniques, an evaluation model will be created. The model will be integrated into a demonstrator and validated. The additional benefits from this project are measurement strategies for thermography and CT to better quantify the CFRP damages. The results will improve the quality assurance of CFRP and will enable reliable repair processes. The model can be extended to other materials and defects.