纤维－金属层板结构蠕变－固化复合成形制造基础研究

With the rapid development of the aerospace, automobile, rail transportation and other areas, the requirements for the lightweight and damage tolerance material are increasing significantly. The R＆D and application of the high performance and lightweight hybrid structure, as represented by the fiber metal laminates (FMLs) are particularly urgent. This project aimed at the problem that the traditional methods separate the manufacturing of laminate material (properties) and structures forming (shape) in different time and space, which are difficult to achieve the co-evolution of the shape and properties. A new method is put forward which combining metal’s creep and composites’ curing within autoclave to integrate the thermal and force fields in space and time needed both by the properties and shape forming. Through researching the formation and evolution mechanisms of the metal (high strength aluminum alloy), fiber reinforced resin matrix composites and fiber-metal bonding interface under the complex thermal and force fields, finding the interconnection rules among the material-process-microstructure-property of the whole process that the new generation fiber metal laminates structure forms with the autoclave. Then breaking through the bottleneck of performance and shape integrated manufacturing for the fiber metal laminates complex structures, achieving the collaborative manufacturing of the material properties and structural precision accompanied by the changing from material to component. Ultimately it will enhance the manufacturing level of fiber metal laminates structure in our country, develop the theory and technology for the high performance and precision forming of complex components, improve our country’s self-dependent innovation and self-supporting ability for high-end equipment manufacturing.

随着航空航天、汽车、轨道交通等领域的飞速发展，对材料的损伤容限性能及轻量化程度的要求越来越高，以纤维金属层板为代表的高性能轻质混杂结构的研发与应用显得尤为迫切。本项目针对传统纤维金属层板结构制造将层板制造（成性）与结构制造（成形）时空分离，难以实现形、性协同演变的难题，提出热压罐蠕变－固化复合成形制造新方法，将成形与成性所需热、力能场条件在时空集成，通过对金属（高强铝合金）、纤维增强树脂基复合材料以及金属－纤维胶接界面在复杂热、力能场条件下形、性演变机理和规律的深刻认识，掌握新一代纤维金属层板结构热压罐蠕变－固化复合成形制造全过程材料－工艺－组织－性能关联规律，突破纤维金属层板结构成形成性一体化制造技术瓶颈，实现材料向构件转变过程材料性能与成形精度的协同制造，提升我国纤维金属层板结构制造水平，发展复杂构件高性能精确成形理论与技术，增强我国高端装备成形制造的自主创新和自主保障能力。

项目针对纤维金属层板开展蠕变-固化复合成形制造基础研究，对其中涉及的复杂热/力成形条件下形性演变机理、缺陷产生机制、复合成形过程本构建模和多场耦合分析、典型构件蠕变-固化复合成形制造工艺试验与变形控制等方面开展了系统深入研究，取得的主要研究结论和成果如下：1）揭示了压力、温度和时间等成形工艺参数对纤维金属层板形变、固化及组织性能的作用机制：在高温和应力作用下，铝合金发生蠕变行为，应力增大改变了可动位错密度，提高了铝合金蠕变速率，晶内析出相产生使得铝合金强度提高。树脂在温度、压力作用下发生固化反应，随着成形压力的降低（＜0.4MPa），树脂基体内孔隙不断融合长大，导致层板层间剪切强度和抗冲击性能降低；2）自主设计构建了纤维金属层板复合成形过程动态在线监测软硬件平台，获得了纤维金属层板蠕变-固化复合成形过程中应力、应变演变规律：应力、应变随温度变化（升温、保温、降温）分为三个阶段，主要产生于保温和降温过程，由树脂固化收缩和金属、复合材料热膨胀不匹配引起。据此，提出了通过在树脂凝胶点附近增设保温平台降低残余应力新方法，残余应力可降低20%以上；3）基于铝合金蠕变本构模型、复合材料粘弹性本构模型和异质界面作用关系，建立了纤维金属层板蠕变-固化统一本构关系模型，为此类构件蠕变-固化复合成形过程形性演变精确预测提供了理论基础；4）通过对有限元程序进行二次开发，将统一本构模型引入商用ABAQUS分析软件，实现了纤维金属层板构件蠕变-固化复合成形全过程形性演变精确预测；5）以航天复杂曲面贮箱瓜瓣构件为研究对象，提出了型面动态加权回弹补偿、高效均匀传热与变形控制的模具优化设计方法，研制了成形模具，并开展了蠕变-固化复合成形工艺实验，实现了构件高品质制造，验证了技术可行性。.本项目的研究工作在国内外高水平期刊发表论文33篇（SCI论文27篇）；授权国家专利15项、软件著作权1项；培养硕/博士生10人。研究成果为解决复杂薄壁纤维金属层板构件高品质制造难题提供了创新方法，发展了复杂薄壁构件高性能精确成形理论与技术，为我国高端装备发展提供重要支撑。