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（制造仿真和结构分析）来减少复合结构部件制造过程中的缺陷，并通过更精确地了解潜在的工艺关系来减小工艺偏差。目前有必要进行研究，因为目前的知识只涉及单个过程步骤，而且还没有通过整个过程链进行过程模拟。本项目的具体目标是建立风电转子叶片复合材料结构件制造的虚拟工艺链。为了能够预测结构构件的机械强度，制造过程采用悬垂搬运模拟和灌注模拟来表示，并以适当的方式将固化过程纳入结构分析。所得的工艺参数与粗纱的实际位置和树脂饱和度有关，可用于所制造的复合材料部件的强度分析的最后一步。在系统的数值研究中，采用适当的有限元模型量化了制造过程中缺陷对结构性能的影响。在过程模拟的各个阶段进行概率分析，其中考虑了缺陷的统计分布，提供了相应的结构特性的散点。对整个过程链的分析——制造模拟和结构分析——使模拟与生产有关的缺陷对结构行为的影响成为可能，并规定与制造过程有关的缺陷公差。这是通过提出的新方法实现的，其中最相关的缺陷（例如几何偏差或材料属性的分散）包括在不同的建模级别。为此，本文从微观尺度（单纤维）、中观尺度（粗纱）和宏观尺度（粗纱复合）三个层面对复合材料进行了详细的分析。在整个过程链模拟结果的基础上，可以建立缺陷容限的标准和设计规则-在典型的相关结构部件的制造过程中可以被认为是可接受的缺陷-从而可以降低产品报废率并促进认证过程。

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.