三维机织复合材料异型构件残余应力形成机制及分析方法研究

The application of three-dimensional (3D) woven composites in aerospace and aviation industries shows a trend from simple revolving bodies to complex heterotypic structures. 3D woven composite heterotypic components usually show more severe residual stress than simple revolving bodies, which has a direct influence on the quality and performance of products. How to accurately predict the residual stress distribution within the composite material, find the major control factors, and reduce the concentration of residual stresses provides a theoretical guidance for the profile and performance control of the heterotypic composite components. This project focuses on the twisted heterotypic structure of aero-engine blades. Yarn reorientations, configuration changes and intrinsic stresses caused by yarn interactions when the preform is shaped by molds are characterized experimentally, in order to reveal the yarn deformation mechanism within the preform. The forming mechanism of residual stresses in 3D woven composite heterotypic structures is analyzed. Then a model is proposed to predict residual stresses by solid model reconstruction and the element embedding method, considering the effects of yarn configurations, yarn orientations and intrinsic stresses. The influence of meso-structure changes in heterotypic components on their residual stresses is illustrated. Finally, the control scheme of residual stresses is established. This project will become a theoretical and technical support for the structural design and process optimization of 3D woven composite heterotypic components.

三维机织复合材料在航空航天领域的应用，表现出从简单回转体到复杂异型结构的发展趋势。相对于简单回转体，三维机织复合材料异型构件制造过程中残余应力更加严重，直接影响构件的成型质量和服役性能。如何能够准确预测复合材料内部的残余应力分布，找到主要控制因素，减少残余应力的集中，将对异型复合材料构件控形和控性设计提供理论指导。本项目针对航空发动机叶片异型结构为对象，实验表征纤维预制体合模赋形时产生的纱线形态、走向的变化以及纱线之间相互作用引发的内禀力，揭示预制体的纱线变形机理；分析三维机织复合材料异型构件残余应力的形成机制，采用实体模型重构和单元嵌入法，提出一种考虑纱线形态、走向和预制体内禀力作用的复合材料残余应力预报模型，阐述异型构件细观结构变化对残余应力的影响规律，建立残余应力的控制方法，为三维机织复合材料异型构件的结构设计和工艺优化提供理论和技术支撑。

三维机织复合材料在航空航天领域的应用，表现出从简单回转体到复杂异型结构的发展趋势。相对于简单回转体，三维机织复合材料异型构件制造过程中纤维变形、固化残余应力及变形问题更加严重，直接影响构件的成型质量和服役性能。如何能够准确预测复合材料纤维走向分布，对复合材料异型构件固化残余应力及变形进行分析预报，具有重要的理论价值和工程意义。本项目针对航空发动机叶片异型结构为对象，表征纤维预制体赋形时产生的纱线形态、走向的变化，揭示预制体的纱线变形机理；分析三维机织复合材料异型构件的全场细观纱线变形情况，在此基础上建立三维机织异形复合材料结构的残余应力及固化变形预报模型，阐述异型构件细观结构变化对固化的影响规律，建立固化变形控制方法，为三维机织复合材料异型构件的结构设计和工艺优化提供理论和技术支撑。