三维整体编织复合材料与结构的制备及低/高温疲劳力学性能演化特性与失效机理研究

Three dimensional (3D) braided composites and structures reinforced with resin have potential applications in aerospace and other fields. In this project, the experimental and theoretical studies on the evolution characteristics of low/high-temperature fatigue properties and failure mechanism of 3D braided materials and structures are carried out. Mainly includes: the design and fabrication of 3D braiding composites and structures (beams, plates, columns, shell) with resin-matrix reinforcement, experimental study on low / high-temperature fatigue properties evolution behavior and failure under the complex environment, determine the various factors affecting the fatigue performance; Through the introduction of variable temperature, time and fatigue parameters, establishing macro and meso mechanical model of low / high-temperature fatigue properties evolution characteristics of 3D braided composites and structures, and study the relationship between fatigue failure mechanism and microstructure and ambient temperature; To develop and expand the nonlinear dynamic finite element method, simulating the low / high-temperature fatigue evolution behavior and the failure process of 3D braided composite and structures; And providing the evaluation system which is suitable for low / high-temperature fatigue properties evolution characteristics of 3D braided composites and structures. The purpose of this project is to provide an exploratory method for the characterization and evaluation of the low-temperature and high-temperature fatigue properties evolution behavior of 3D braided composites and structural systems. At the same time, it also provides some theoretical basis and technical reserves for the application of 3D braided composites and structures.

树脂基三维整体编织复合材料与结构，在航空航天等领域具有潜在应用价值。本项目主要对这类编织材料与结构的低/高温疲劳力学性能演化特性和失效机理进行实验与理论研究。主要包括：设计与制备树脂基三维编织复合材料与结构体系（梁、板、柱、壳），实验研究复杂环境下材料与结构的低/高温疲劳力学性能演化特性与破坏，确定影响疲劳性能的各种因素；通过引入温度、时间和疲劳参数，建立编织材料与结构低/高温疲劳力学性能演化特性的宏细观力学模型，研究疲劳失效机理与其细观结构和环境温度的关系；对非线性动态有限元技术进行开发和拓展，模拟编织材料与结构的低/高温疲劳性能演化和失效过程；提出适用于编织复合材料与结构体系低/高温疲劳力学性能演化特性的评价体系。本项目研究目的在于为三维编织复合材料与结构体系低/高温疲劳力学性能演化特性的表征与评价提供一种探索性的方法。同时，也为编织复合材料与结构体系的应用提供一些理论基础和技术储备。

三维整体编织复合材料是一种新型结构材料，在航空航天领域主承力结构件应用广泛。本项目设计与制备了多种新型三维编织结构复合材料，从实验和理论角度对三维整体编织复合材料不同温度的力学性能、疲劳特性和损伤失效规律进行了研究，主要工作包括：（1）三维多向整体编织预制件与复合材料的设计与制备。设计与制备了不同编织结构、不同编织角、不同纤维体积含量、不同厚度的碳纤维三维多向整体编织预制件和增强复合材料。（2）三维五向编织复合材料常温面内压缩疲劳性能与失效机理研究。获得了三维五向编织复合材料的常温面内横向与纵向压缩疲劳性能，并揭示了相应的疲劳失效机理。（3）三维五向编织复合材料高/低温纵向压缩疲劳性能与失效机理的实验与理论研究。从理论和实验角度获得了三维五向编织复合材料高/低温纵向压缩疲劳性能，揭示了相应的疲劳失效机理，明晰了温度与编织角对材料疲劳性能的影响规律。（4）三维五向编织复合材料横向弯曲疲劳性能与失效机理研究。获得了三维五向编织复合材料的横向弯曲疲劳性能，并揭示了横向弯曲疲劳失效机理。（5）三维六向编织复合材料的拉伸疲劳性能与失效机理研究。获得了三维六向编织复合材料的拉伸疲劳性能，并揭示了拉伸疲劳失效机理。（6）三维多向编织复合材料的力学性能及失效机理的计算研究。基于三维四向编织复合材料中纤维束的空间取向，考虑纤维束横截面的挤压，建立了参数化中尺度三维有限元模型，预测了材料的拉伸和压缩应力-应变曲线、强度及损伤失效、阐释了编织角、纤维体积含量及加载模式的影响规律，揭示了相应的拉伸和压缩失效机理。研究成果为三维整体编织复合材料结构的设计和应用提供了理论基础和技术储备。