编织复合材料/金属叠层干涉连接界面损伤演化机理多尺度研究

The interference-fit joint can improve the bearing capacity and sealing performance of woven fabric composite (WFC)/metal stacks. However, there is a significant difference between the heterogeneous stacks materials. The assembly and service process will cause stress concentration and damage around the interference-fit interface, which severely impact the safety and reliability of the products. This project focuses on the cross-scale information transfer method and superimposed stress field modeling of the interference-fit interface, the damage initiation and evolution around the interference-fit interface of WFC/metal stacks will be investigated from microscale to macroscale. The elastoplastic and damage mechanical behavior of fiber, matrix and bonding interface in microscale will be explored to indicate the deformation and damage mechanism of woven representative volume element (WRVE) in mesoscale. Then, a unified multi-scale constitutive model will be proposed for WFC by cross-scale correlation and transfer of displacement and stress. Taking variable support stiffness into consideration, non-uniform stress distribution and mixed delamination damage of the stacks will be founded during assembly process. On base of which, a superposed stress field model will be established under service load to predict damage evolution behavior of interference-fit interface. Finally, an optimization method will be proposed to design and assemble the stacks with interference-fit joint. The research achievements of this project have remarkable scientific significance and widely application value to support the safely and reliably of WFC/metal stacks in the field of aviation, aerospace and vehicle.

干涉连接技术能有效提高编织复合材料（WFC）/金属叠层复合构件的承载和密封性能，但叠层异质材料性能差异巨大，干涉挤压和工作承载会引起连接界面应力集中和复杂损伤，严重影响产品的安全性和可靠性。本项目围绕WFC跨尺度信息传递、干涉界面叠加应力场建模等科学问题，从微观到宏观多尺度深入研究叠层构件干涉界面损伤萌生与演化规律。探索纤维、基体及其界面等微观组成相的弹塑性和损伤力学行为；揭示编织型细观特征单元多向挤压作用下的变形-损伤演化机理；通过跨尺度位移与应力等信息关联与传递，建立WFC多尺度统一本构模型；探索变刚度支撑下叠层界面连接挤压应力非均匀分布及混合分层损伤萌生机理；构建工作载荷约束下界面应力场叠加模型，形成损伤扩展与演化规律预测方法，实现叠层干涉连接结构和装配工艺的优化设计，为WFC/金属叠层复合构件干涉连接新结构在航空、航天、汽车等产品中更加安全、可靠应用提供理论方法与技术支持。

本项目针对汽车、飞机等重量敏感型产品在轻量化设计过程中广泛存在的编织复合材料（WFC）/金属叠层构件，结合干涉连接技术良好的密封、承载和抗疲劳特性，对叠层异质构件的干涉连接界面损伤的多尺度演化机理展开了深入研究，主要工作：1）提出了改进随机序列扩张法和随机扰动法等两种碳纤维随机分布算法，建立了考虑编织工艺过程的WFC微观WRVE模型，分析了WRVE挤压损伤规律；2）建立了叠层构件干涉界面和叠层界面的孔周应力非均匀分布模型，提出了干涉插钉分层损伤的临界轴向力预测模型，分析了挤压损伤和分层损伤的萌生机理；3）揭示了工作载荷作用下初始连接损伤的扩展演化规律，分析了摩擦系数和拧紧力矩等参数对损伤演化的影响，得到了拉伸强度约束下的最优拧紧力矩，为WFC/金属叠层复合构件干涉连接新结构的设计与装配决策提供了基础理论与技术支持，促进了复合材料在航空、汽车、风电等工业领域的应用，为世界节能减排和可持续发展贡献力量。目前结合项目研究内容，已发表学术论文6篇，其中SCI检索论文2篇，国内EI检索论文2篇，另外还有SCI源刊和EI源刊论文各1篇录用待刊；申请发明专利和实用新型专利各2项，发明专利处于公开审查阶段，实用新型专利已授权；培养博士后1人，硕士研究生4人，参加国内国际学术会议2次。