热塑性超混杂复合材料汽车零部件的材料•结构设计及成型工艺研究

“Thermoplastic Super Hybrid Composite” based on mixture of multiple material constituents can not only exploit the advantages of various different material constituents, but also adjust the ratios of these material constituents to develop the light-weight automobile parts of superior performances and reduce the cost. Therefore, it represents a new development direction of light-weight materials of automobiles in the future. For the common scientific issues in the molding process, interface property modulation, material/structural design and theoretical analysis of the thermoplastic super hybrid composites, the following research contents will be carried out in this project. We will systematically study the deformation of fabrics, mechanisms of defect formation and control methods of hot stamping and shaping process of automobile body structural parts made from the thermoplastic super hybrid composites. The influences of molding parameters on the residual stress of the structural parts and curing deformation will be investigated to optimize the molding process. We will utilize the combination of surface treatments of metals and techniques of interleaves to regulate and control the interfacial mechanical properties and uncover the toughing mechanisms. By considering the coupling of manifold effects, e.g., strain rate, we will establish the multi-scale parametric theoretical analysis and finite element models to predict the mechanical properties of the thermoplastic super hybrid composites, and set up the multi-level optimization methods for the materials and corresponding structures. Finally, we will experimentally measure and analyze the properties of the thermoplastic super hybrid composites and their typical parts to verify our theoretical and numerical models. The outcomes of the present research will provide the effective common theoretical basis and technical supports for the efficient manufacturing and accelerated applications of automobile body parts based on the thermoplastic super hybrid composites.

多材料混合的“热塑性超混杂复合材料”不仅可以充分利用各种材料的优点，还可以通过调整材料的组分配比开发出轻质•性能优越的汽车零部件并有效地降低成本，是未来汽车轻量化材料的发展新方向。本项目围绕热塑性超混杂复合材料在成型工艺、界面性能调控、材料•结构设计以及理论分析方面的共性科学问题展开：系统研究热塑性超混杂复合材料车身结构件热冲压成形中纤维织物的变形、缺陷产生机理和控制方法，探究成型工艺参数对结构件残余应力和固化变形的影响规律并优化工艺；通过金属表面处理和层间插层技术的结合对界面力学性能进行调控并揭示其强韧化机理；考虑应变率等多效应耦合建立其力学性能预测的多尺度参数化理论分析和有限元模型，构建材料•结构的多层次设计方法；最后对材料及典型零部件性能进行测试分析并与理论•计算模型进行对比验证。项目的研究成果将为热塑性超混杂复合材料车身零部件的高效制造与加速应用提供有力的共性理论基础和技术支撑。

为解决高效低成本超混杂复合材料在汽车轻量化结构件应用中的基础问题，项目组对热冲压成型过程预浸料变形、缺陷控制、残余应力、固化变形、界面调控、性能预测等方面进行了多项研究：.推导了纤维织物预浸料剪切应变能函数形式，并据此建立了参数易得的织物各向异性超弹性模型；在各向异性超粘弹性本构模型中引入粘性能，建立了各向异性超粘弹性本构模型用于描述冲压过程。建立了热塑性树脂温度、结晶度相关的黏弹性本构模型和相应的各向异性黏弹性本构模型，用于结构件的固化结晶分析和残余应力、残余应变分析。针对构件固化过程，建立了代理模型，而后使用遗传算法以最小残余应变为设计目标对超混杂复合材料成型过程的工艺参数进行了优化。结合试验与计算手段，研究了金属表面微结构对界面性能的影响，并对界面进行了参数化表征，建立了基于多尺度分析的超混杂结构界面内聚区模型，进一步发展了内聚力模型方法。通过试验测试和数值模拟揭示了混合连接中金属、复材的竞争失效机理，对顶盖中横梁、汽车B柱等特定构件进行了力学性能测试与失效过程仿真，发展了多尺度分析方法。研究成果应用于超混杂复合材料构件的结构、工艺的一体化设计，为超混杂复合材料在汽车结构件成型工艺的提升提供了技术支持。