热塑性自动铺丝缺陷多尺度行为特性及演变机制研究

Automated Fiber Placement (AFP) is an automatic technology for thermoplastic composites, which can achieve the in-situ curing for integral construction of large aerospace composite components. Its manufacturing defects affect the quality and reliability of composite products directly. This project focuses on the multi-scale characteristics of the defects that occur, enlarge and converge. And the main line of this project is aimed at multi-scale formation mechanism for the defects. The formation and evolution mechanism of the defects, including porosities, cracks and delaminations, are revealed based on nonlinear dynamic behavior of bubbles, macro-meso-scopic FEM theory of composites and dynamic characteristics of stress during AFP process. Multi-scale energy transfer model is presented to build the energy communication mechanism among different scales by using multi-scale theory and composite mechanics. The molecular model of prepreg and its defects are established by utilizing the molecular dynamics method. The response characteristics of defects formations and evolutions to microscopic mechanics parameters are analyzed. The formation and evolution characteristics of microscopic defects are further explored. The coupling of processing parameters, multi-scale mechanical properties and the defects is solved by employing the gray correlation method and analytic hierarchy process. Following that a multi-scale collaborative optimization method is proposed. The achievements of this project will lay theoretical basis for low-defect manufacturing during AFP process and promote the application of this technology in Large Plane Project.

热塑性自动铺丝是一种可实现大型航空复合材料构件整体原位固化成型的自动化工艺，其制造缺陷将直接影响产品的质量和可靠性。本项目拟针对热塑性自动铺丝缺陷生成及演变的多尺度特性，以缺陷的多尺度演变机制为研究主线，通过分析气泡的非线性动力学流变行为，并融合复合材料宏细观有限元理论和铺丝过程中应力的动态特性，揭示孔隙、裂纹、分层缺陷的宏细观生成与演变机制；基于多尺度理论和复合材料力学，提出多尺度能量传递模型，建立宏细观与微观尺度下的能量沟通机制；运用分子动力学方法，构建预浸丝及其缺陷的微观分子模型，分析缺陷生成和演变对微观力学参数的响应特性，探究微缺陷的生成和演变特征；采用灰色关联和层次分析法，构建工艺参数、多尺度力学特性和制造缺陷复杂耦合关系的解耦策略，并提出多尺度协同工艺优化方法。研究成果将为热塑性自动铺丝构件的低缺陷制造奠定理论基础，进而促进该技术在我国大飞机工程中的应用。

自动铺丝成型高性能热塑性复合材料对航空航天领域大型结构件快速制造具有重要的研究意义。本项目针对自动铺丝成型CF/PEEK高性能热塑性复合材料缺陷及工艺的多尺度行为特性分析开展研究工作。融合多尺度理论和复合材料力学，构建了不同尺度上的能量传递模型。在宏微观尺度下，运用复合材料力学理论和分子动力学方法，建立了铺丝过程中的热力耦合动力学模型和预浸丝界面缺陷的微观系统模型，分析了不同工艺条件下宏微观力学参数和能量状态，揭示了自动铺丝制造过程中工艺与缺陷及性能之间的影响规律。利用灰色关联分析法阐明了工艺参数与缺陷及性能之间的耦合关系紧密程度，并提出了多尺度协同工艺优化方法。研究成果将为自动铺丝成型低缺陷高性能的热塑性复合材料构件的快速制造奠定理论及实践基础。