In this paper, a novel numerical simulation framework using meso-scale finite element model is developed to predict the mechanical properties and damage mechanisms for one-layer biaxial braided composite tubes with gradient braided structures in axial direction, which involves braided reinforcements with an evolution of braiding angle. To bridge the relationships between the braiding procedure and geometric model, this paper develops an automatic algorithm that generates the geometric model with requiring braiding parameters as input parameters. The braided fabric model is generated by circularly arraying the yarn model, which is established by sweeping varying cross-sections along the centerline with the control of guidelines. The geometric model of matrix pockets is obtained by extracting the fabric model from the whole geometric model of composite tube. After that, a braiding yarn mesh in hexahedron format and co-node matrix mesh in tetrahedron format are generated from the assembled braided fabric and matrix pockets. The framework established in this paper is validated by comparison with the experimental results of the composite tubes with braiding angles from 36.6° to 49.6° subjected to quasi-static axial compression.

本文建立了一种新型的数值模拟框架，该框架使用了中尺度有限元模型来预测具有梯度编织结构的单轴双轴编织复合材料管在轴向上的力学性能和损伤机理，其中涉及到编织增强物。编织角。为了桥接编织过程和几何模型之间的关系，本文开发了一种自动算法，该算法可生成以编织参数为输入参数的几何模型。编织的织物模型是通过将纱线模型圆形排列而生成的，该纱线模型是通过在准则的控制下沿中心线扫掠不同的横截面而建立的。矩阵袋的几何模型是通过从复合管的整个几何模型中提取织物模型而获得的。之后，从组装的编织织物和基体袋中生成六面体格式的编织纱网和四面体格式的同节点矩阵网。通过与编织角度为36.6°至49.6°的准静态轴向压缩复合管的实验结果进行比较，验证了本文建立的框架。