基于含损纱线系统动力学模型的碳纤维预成型体三维编织优化与控制

Three-dimensional braided carbon fiber preforms have important applications in defense aircraft and important people's livelihoods, such as some vital parts of large aircrafts, launch vehicles and long-range missiles etc. However, when automatically braiding large-scale preforms, the friction and wear of carbon fiber are severe, which directly affects the stability of the braiding processes and the quality of preforms; in order to solve the above problem, this project proposes an optimization and control method for the three-dimensional braiding processed large-scale carbon fiber preforms, which is based on the dynamic model of damaged yarns system. It needs two steps to realize the method. Firstly, by the transfer matrix method, yarn braiding unit models with different yarn behaviors will be proposed. Then according to the parametric coupling relationship among the unit models, the values of parameters and the boundary conditions of each unit models will be decoupled to derive the dynamic model of the three-dimensional braiding processes considering damaged yarns. Secondly, the online non-destructive testing method for yarn damage needs to be studied. The dynamic performance parameters of yarns for different degrees of yarn damage could be evaluated, and results could be fed back to a dynamic model based algorithm. By the algorithm, parameters of three-dimensional braiding processes could be adjusted, leading to reducing the yarn damage, and optimizing the dynamic performance parameters of the end yarns. Based on the above, the purpose of improving the stabilization of braiding processes and braids quality could be achieved, which could provide a theoretical guidance for the automatic manufacture of three-dimensional carbon fiber composite preforms.

碳纤维预成型体三维织物在大型飞行器、运载火箭和远程导弹等国防军工和重要民生领域均有重要应用，但自动化编织时普遍存在纤维磨损，尤其在编织大尺寸预成型体时，纤维损伤极为严重，直接影响编织过程稳定性和预成型体质量；针对该问题，本项目提出一种基于含损纱线系统动力学模型的碳纤维预成型体三维编织优化与控制方法，分两步实现：首先，建立不同编织行为下的含损纱线编织单元模型，结合各单元模型间参数耦合关系和边界条件，解耦并建立含损纱线的三维编织系统动力学模型；其次，通过机器视觉手段，研究纱线损伤的在线无损检测与控制方法，通过该检测方法评估不同含损纱线的动力学性能参数，将结果反馈到基于动力学模型构建的算法中，对工艺参数进行寻优调控，减少编织过程中的纱线损伤，优化编织末端纱线动力学性能参数；综上研究，以期达到稳定编织过程、提高织物质量的目的，为实现大尺寸碳纤维预成型体三维自动编织技术产业化提供理论指导。

三维维编织碳纤维复材预成型体整体性好，抵抗层间分离能力强；近净设计制造，不需要缝合和机械加工；同时参与编织的纤维束多，生产效率高，自动化程度高，被誉为复材预成型体的最佳成型方式和最佳生产方式。随着国家“双碳”战略的实施和“海、地、空”实力不断提升，对复合材料的需求急剧增加，因此，需要开展碳纤维复材预成型体三维编织装备技术的研发。本项目针对三维编织过程中碳纤维损伤影响编织的问题，提出将碳纤维损伤考虑到三维编织工艺过程中，从而可以提高编织装备的整体可靠性和工艺稳定性。建立了三维编织系统锭轨耦合动力学模型，分析了存在纤维损伤等外界扰动情况下锭轨耦合的动态特性；提出了碳纤维编织预成型体性能与结构参数、成型工艺参数的数学模型，揭示了不同织物结构的性能与结构工艺参数内在关系，为实现数字化设计提供理论指导；基于机器视觉方法，对碳纤维编织过程中纤维状态与关键参数进行对照分析，通过优化关键参数实现对纤维损伤的定量控制；设计并研制了纱线损伤测量与控制平台，提出了离散角均值灰度编织角检测算法和基于改进改进Faster R-CNN算法，实现了对多种碳纤维预成型体织物的关键结构工艺参数和表面质量的检测。本项目的研究对研发适合大尺寸碳纤维复合材料预成型体的自动化编织工艺和提高编织质量意义重大，将促进纱线损伤在编织过程中的作用机理及纱线间相互作用关系的深入理解，研究成果将有助于大尺寸碳纤维复合材料三维织物的制备，推动编织工艺相关理论的发展和完善。