中文摘要：

采用多尺度耦合的数值模型研究了圆管状立体机织复合材料的力学性能。建立了反映纤维束中纤维/基体二相材料的微观尺度单胞和反映周期性编织结构的细观尺度扇形单胞,并重点讨论了扇形单胞的周期性边界条件。通过逐级计算微观单胞、细观单胞的平均弹性常数,得到了圆管状立体机织复合材料的刚度参数,实现了由组分材料性能及编织参数预测圆管的宏观弹性性能,模型预测刚度与试验结果吻合。另一方面,研究了从大到小各尺度耦合的应力分析,对于圆管环向应力非周期分布的情况,建立了嵌入细观单胞的环状模型,进行了复杂荷载下从宏观圆管结构、到细观纤维束尺度、再到微观纤维尺度之间的逐级应力分析。

英文摘要：

A multi-scale coupled numerical model was developed to investigate the mechanical behaviors of 3D woven composite pipes.Micro-and meso-scale unit cells were built to represent the inhomogeneity of fiber tow and weave structure of a 3D woven composite pipe,respectively.The periodic boundary condition of the camber shape meso-scale unit cell was specified.The macro-scale stiffness of the 3D woven composite pipe was obtained by averaging the stiffness on unit cells from micro-scale to meso-scale.The stiffness prediction is in good agreement with experimental results.On the other hand,using the multi-scale unit cells,the converse stress analysis process under multi-axial loads was carried out,i.e.to transfer stresses from macro-scale to meso-scale and finally to micro-scale.A model of embedding the meso-unit cell into a homogenous ring was suggested for meso-scale stress analysis in case of applied loads without periodicity in the annular direction.