变刚度复合材料结构设计与铺放成型工艺性关键技术研究

The variable-stiffness, fiber-steered composite structures belong to a recently-developed novel class of anisotropically variable-angle laminates based on curvilinear fiber steering techniques. The variable-stiffness composites have brought unprecedented opportunities to improve the structural performance and reduce the production cost of composite structures; on the other hand, the unique configuration of the variable-stiffness composites leads to new challenges for composite design and manufacturing: (1) variable-stiffness composite design and optimization based on curvilinear fiber patterns; (2) fiber path planning satisfying both structural performance and manufacturability; (3) viscosity mechanism and process control of prepregs used for placing variable-stiffness composites. Therefore, this project will focus on the three key technologies concerning variable-stiffness composites: structural design and optimization, multidisciplinary planning of steered fiber paths, manufacturability and its controlling principles. The goal of this project is to propose the structural design theory and methods for variable-stiffness laminates, to investigate the scientific laws of steered fiber path planning, to explore the viscosity mechanism of the used prepregs and the process design of the fiber steering, to reveal the mechanism of manufacturing defect formation during fiber steering process, and to build the simulation and on-line monitoring platform for verifying the accuracy of manufacture and manufacturing defect. This project will construct the research platform for key technologies raised from variable-stiffness composite design and manufacturability, based on the integration of materials, structures, and processes. The expected results will provide novel principles and methods for variable-stiffness, fiber-steered composite design, manufacture and test.

变刚度复合材料是近年发展起来的一种基于曲线纤维铺放技术的新型各向异性变角度铺层结构，为提高复合材料结构性能和降低成本带来了前所未有的机遇，同时也对复合材料结构设计与制造理论提出了新的挑战：基于曲线铺放模式的变刚度结构设计与优化、满足优良结构性能与制造工艺性的变刚度铺放路径规划、变刚度铺放预浸料粘性机理与工艺性调控等。因此，本项目将围绕变刚度复合材料的“结构设计与优化方法”、“铺放路径多学科规划方法”和“铺放工艺性及调控机理”三个关键技术问题，提出变刚度铺层结构设计理论与方法，研究变刚度曲线铺放轨迹规划的科学规律，探索预浸料粘性规律和变刚度铺放工艺设计方法，揭示变刚度铺放过程缺陷形成机理，建立制造符合性仿真验证平台和铺放过程缺陷在线检测平台。该项目将构建基于材料-结构-工艺一体化的变刚度复合材料结构设计与铺放工艺性关键技术研究平台，为变刚度复合材料设计、制造与检测提供新原理与新方法。

为提高复合材料结构性能，我们对变刚度复合材料的铺放工艺机理与调控、铺放路径规划、结构设计与优化方法进行了系统研究。.我们研究了铺放过程中预浸料层间黏性的定量表征方法及其影响机理，构建了探针和剥离实验系统。通过建立含内聚力模型的剥离仿真模型和紧密接触理论，验证了内聚力模型模拟胶层失效的正确性，实现了铺放工艺窗口的优化与调控。.我们对不同模式和参数的铺放轨迹进行研究，开发了不同纤维轨迹层合板的快速建模插件。研究了矩形层合板的振动特性的建模和求解方法，通过改进优化程序对不同边界条件、尺寸参数的变刚度层合板进行了振动特性求解与优化并进行测试验证。.对非矩形层合板，我们通过有限元和数学计算结合建立了多目标优化方法，对不同边界条件的层合板进行频率和阻尼优化并进行试验测试，结果表明改变轨迹参数可以同时兼顾两个优化目标的大幅提升。.我们在传统化曲为直的建模方法基础上，考虑重叠、间隙等因素建立了精细化的变刚度建模方法，我们通过实验研究了预浸料的变角度铺放范围，并对变刚度层合板进行力学分析及结构性能优化。基于自动铺丝设备，研究了变刚度铺放路径设计和铺层优化分析，开展其平板试验件和长桁件的制备。.本项目执行四年来，共完成学术论文24篇，其中SCI检索12篇，EI检索13篇，授权发明专利14项，参加高水平学术会议33人次，完成了计划书的主要内容。本项目所取得成果均属于课题成员的原创性研究，具有很强的前沿性和普适性，在显著提高变刚度复合材料结构性能上进行了工艺设计和结构优化的积极有益尝试。研究成果预计将对我国航空航天、交通运输等领域有着非常重要的应用基础研究意义。