三维编织复合材料的动态热力耦合和细观结构设计

Three-Dimensional (3-D) braided composite has high fracture toughness and impact damage tolerance. This feature leads to the great potential applications of the 3-D braided composites under impact loading. But it is rather difficult to estimate the strength of the 3-D braided composite because of its multiple failure mechanisms. Here a multi-scale microstructure model including thermo-mechanical coupling response will be established to investigate the impact properties of 3-D braided composite in temperature fields. This model will cover form fiber, yarn, unit-cell to composite. A series of impact testes will be conducted to study impact properties and deformations. A user-defined subroutine will be compiled which includes strain rate effect and temperature effect. The commercial FEM software package ABAQUS/Explicit combining the subroutine will be used to simulate impact damage and analyze thermo-mechanical coupling responses of 3-D braided composite, forming a method of impact mechanism. Except for obvious practical application background, this project will enlarge the research scope of impact dynamics and composite material science on a new level.

三维编织复合材料的高断裂韧性和冲击损伤容限使其在冲击加载下具有其它复合材料不可替代的特殊优势。但多重破坏机制使试件的强度难以预测，复合材料力学性质的可设计性使三维编织复合材料强度有较大的设计空间。本项目将建立考虑热力耦合的从纤维、纱线、单胞到复合材料的多尺度细观结构模型；开展系列不同温度场下的冲击实验，研究不同参数三维编织复合材料冲击变形过程，应力应变曲线和比吸收能；编制计及应变率效应和温度效应的用户材料子程序，结合有限元程序包ABAQUS/Explicit计算不同温度场下静态、冲击加载条件下三维编织复合材料的破坏和变形，预测试件静、冲击加载下的应力应变曲线、强度和能量吸收，揭示三维编织复合材料在冲击加载下的破坏机理和热力耦合效应，形成可直接用于三维编织复合材料考虑热力耦合的冲击性能设计方法。该项目除了具有明显的工程应用背景外，从更深层面上拓展了冲击动力学和复合材料学的研究内容。

项目研究了三维编织复合材料在高/低温及冲击压缩加载下热力耦合响应及破坏机理，主要内容包括三维编织复合材料冲击压缩响应、热力耦合冲击压缩破坏过程有限元模拟和绝热状态下材料红外热响应。建立了三维编织复合材料细观结构几何模型，通过实验和推导确定应变率相关、温度依赖材料本构模型。考察了三维编织复合材料温度场下冲击压缩热力耦合失效机理和三维编织复合材料试件冲击压缩红外热成像响应。形成了三维编织复合材料考虑热力耦合的冲击性能设计方法。项目所建热力耦合模型可扩展到其它纺织结构复合材料不同温度场动态冲击加载热力耦合响应行为分析和预测，可为纺织结构复合材料在高速车辆和轻量化汽车和轻质飞行器等领域应用提供强度预测和性能评估。项目也研究了三维角联锁机织复合材料冲击响应细观结构和热力耦合机理，对冲击加载及高温环境下三维机织复合材料的结构设计与优化提供了理论指导。