Effects, Detection and Prediction of Defects in Hybrid Composite Parts for Metal/CFRP-Lightweight Structural Structures Suitable to Large-Volume-Production

创新连接元件的研究为增加碳纤维增强塑料（CFRP）的应用领域提供了潜力。为了达到这一目标，有必要从科学的角度评价它们的功能。这些方面涉及到设计和尺寸，也涉及到零件的生产。在优先计划1712中，已经可以表明，需要在生产过程中检测质量关键缺陷，因为它们会显著降低CFRP和插入组件（插入件）之间的连接功能。这一发现是在所谓的缺陷效应分析中得出的，其中零件和材料的特定缺陷都被故意插入到二维和弯曲的接头中。力学试验方法表明单个缺陷对承载能力和其他部件性能的影响，从而识别出关键缺陷类型。通过将非破坏性检测方法同时应用于机械测试，典型的失效行为可以直接与缺陷类型联系起来，从而需要通过在线测量系统在树脂传递成型工艺链中进行检测。项目的目标是基于所描述的初步项目的结果。因此，有必要建立一种开发三维混合接头的基本方法，并确定削弱键合的潜在临界缺陷的尺寸。研究结果用于与设计、无损检测以及混合动力部件生产相关的三阶段控制回路方法。在设计领域，为了影响质量临界缺陷在接头内部的损伤传播，开发和应用了创新的零件构造方法。通过制造带有不同尺寸和位置的故意插入缺陷的零件，应用创新方法，如电感式热成像，可以分析不同的损伤情况。除了初步项目阶段的结果之外，这种方法不仅可以识别关键缺陷，还可以确定需要在生产中检测到的关键缺陷的大小和位置。为此，研究了工艺集成的方法，将热成像和超声波检测集成到生产过程中，以实现制成品的质量控制。为了同时应用不同的测量原理，需要研究一种数据融合方法，以便能够对初步项目产生的热、声和光学数据进行综合分析。此外，将损伤分析的结果返回到设计领域，以提高混合接头对关键缺陷及其特征的不敏感性。

The research on innovative joining elements offers the potential to increase the field of applications in the use of carbon fibre reinforced plastics (CFRP). In order to reach this goal it is necessary to evaluate their functional capability under scientific aspects. These aspects concern the design and dimensioning but also the production of parts. In the Priority Programme 1712 it could already be shown that quality critical defects need to be detected during the production process itself because they significantly contribute to a decreased functionality of the joint connection between CFRP and inserted components (Inserts). This finding was made during a so called Effects of Defects analysis, where both part and material specific defects were purposely inserted into two-dimensional and curved joints. Mechanical testing methods have shown the influences of individual defects on load bearing capacity and other part properties leading to the identification of critical defect types. By applying methods of non-destructive testing simultaneously to the mechanical testing typical failure behaviour could be directly linked to the defect types, leading to the necessity of their detection in the Resin Transfer Moulding process chain by in-line measurement systems. The goal of the project is based on the results of the described preliminary project. Therefore it is necessary to create a basic method for the development of three-dimensional hybrid joints and to determine the dimensions of potential critical defects that are weakening the bond. The findings are used in a three-staged control loop approach that is associated with the design, non-destructive testing as well as the production of hybrid parts. In the field of design, innovative methods of part construction are developed and applied in order to influence the damage propagation inside the joint due to quality critical defects. By manufacturing parts with purposely inserted defects of varying dimensions and locations the application of innovative methods such as the inductive thermography allows the analysis of different damage cases. In addition to the results of the preliminary project phase, this approach not only allows the identification of critical defects but also the determination of critical defect sizes and their positions that need to be detected in production. In order to do so, methods of process integration are investigated for the integration of thermography and ultrasonic testing in the production process for the quality control of manufactured parts. For the simultaneous application of different measurement principles a data fusion approach need to be investigated in order to enable a combined analysis of thermal, acoustic as well as optical data resulting from the preliminary project. Furthermore the findings of the damage analysis are returned to the field of design in order to increase the insensitivity of the hybrid joint towards critical defects and their characteristics.