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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。
The mechanical properties of circular tubular three-dimensional woven composites were investigated by numerical modeling of multi-scale coupling. The microscopic scale unit cells reflecting the fiber / matrix two-phase material in the fiber bundle and the mesoscale fan-shaped unit cells reflecting the periodic braided structure were established, and the periodic boundary conditions of fan-shaped unit cells were discussed. By calculating the average elastic constants of microscopic unit cells and mesoscopic cells step by step, the stiffness parameters of circular tubular three-dimensional woven composites are obtained, and the macroscopic elastic properties of the circular tubes are predicted by the material properties and weaving parameters. The model predictions Stiffness and test results match. On the other hand, the stress analysis of large-scale small-scale coupling is studied. For the non-periodic distribution of circular ring stress, a ring model embedded in mesoscopic cells is established. Under the condition of complex loading, Structure, to the microscopic fiber bundle size, and then to the microscopic fiber dimension by level stress analysis.