Development and validation of a virtual process chain for composite structural components considering imperfections with application to a rotor blade component

该项目旨在通过模拟整个工艺链(制造模拟和结构分析)来减少复合材料结构部件中由于制造而产生的缺陷，并通过对潜在工艺关系的更精确的了解来使工艺偏差更小。目前有必要进行研究，因为目前的知识只涉及各个工艺步骤，而且目前还不能通过整个工艺链进行工艺模拟。本项目以建立风力机叶片复合材料结构件制造的虚拟工艺链为具体目标。为了能够预测结构件的机械强度，将制造过程用悬垂和搬运模拟和注塑模拟来表示，并以适当的方式将固化过程包括在结构分析中。所得到的与粗纱的实际位置和树脂饱和度有关的工艺参数可用于所制造的复合材料部件的最后一步强度分析。在系统的数值研究中，使用适当的有限元模型来量化制造过程中产生的缺陷对结构行为的影响。在工艺模拟的所有阶段中，考虑缺陷的统计分布的概率分析提供结构特性的相应散布。通过对整个工艺链--制造模拟和结构分析--的分析，可以模拟与生产相关的缺陷对结构行为的影响，并指定与制造过程相关的缺陷公差。这尤其是通过提出的新方法来实现的，其中最相关的缺陷(例如，材料特性的几何偏差或散布)被包括在不同的建模水平上。为此，本文从微观(单纤维)、细观(粗纱)和宏观(粗纱-复合材料)三个层面对复合材料进行了详细的分析。根据整个工艺链的模拟结果，可以建立缺陷公差的标准和设计规则--在典型的相关结构部件的制造过程中可以认为是可接受的缺陷，从而可以降低产品废品率并促进认证过程。

This project aims at reducing the flaws due to manufacturing in composite structural components with the help of simulating the full process chain (manufacturing simulation and structural analysis) and at making the process deviations smaller through a more precise knowledge of the underlying process relations. There is a need for research at this moment since the current knowledge relates to the individual process steps only and because a process simulation through the whole process chain is not available as yet. In this project, establishing a virtual process chain for the manufacturing of composite structural components for a wind turbine rotor blade is defined as a concrete objective. In order to be able to predict the mechanical strength of the structural component, the manufacturing process is represented by a draping and handling simulation and an infusion simulation, and the curing process is included in the structural analysis in an appropriate way. The resulting process parameters related to the actual position of the rovings and the resin saturation can be used in the final step of strength analysis of the composite component manufactured. The influence of flaws due to the manufacturing process on the structural behavior is quantified with appropriate Finite Element models in systematic, numerical investigations. Probabilistic analyses in all phases of the process simulation, in which the statistical distribution of imperfections are considered, provide the corresponding scatter of the structural properties. The analysis of the complete process chain - manufacturing simulation and structural analysis - makes it possible to simulate the influence of production related imperfections on the structural behavior and to specify flaw tolerances connected with the manufacturing process. This is achieved in particular through the new approach presented, in which the most relevant imperfections (e.g. geometrical deviations or scatter of material properties) are included at different modeling levels. For this aim, the composite material is analyzed in detail at three levels, the micro-scale (single fiber), the meso-scale (roving) and the macro-scale (roving-composite). On the basis of the results of the simulation of the complete process chain, criteria and design rules for flaw tolerances - flaws which in the manufacturing process of a typical, relevant structural component can be considered as acceptable - can be established, and thereby the product scrap rate can be reduced and certification processes can be facilitated.