三维机织结构的几何模型

A GEOMETRIC MODEL OF THREE DIMENSIONAL WOVEN STRUCTURES

根据三维机织结构中纱线系统的组成和相应纱线的几何形态,建立了具有普适意义的几何模型,获得了组成三维机织结构各纱线系统在一个结构单元内的纱线长度和取向角,进而计算出纤维体积分数。随后,选择了基于11种不同接结组织的三维机织复合材料试样,测试了试样的纤维体积分数,所得的测试结果与模型输出的预测值有很好的一致性。利用所建立的模型还定量讨论了接结组织对纤维体积分数和取向角的影响。结果表明:分层接结可以提供比正交接结高的纤维体积分数;而正交接结中接结经具有较大的取向,有利于增强三维机织复合材料在厚度方向上的力学性能。

Following the geometric pattern of the constituent yarn systems in 3D woven structures, a general purpose geometric cell model is developed. The length and orientation angle of the constituent yarns in each yarn system within a unit cell are calculated, and then the fiber volume fraction of 3D woven composites can be obtained. To verify the geometric model, samples of 3D woven composites with 11 various binding patterns are selected and the fiber volume fraction is measured. Experiment results are in good agreement with the outcomes of the model. Further, the geometrical model is used to discuss the effects of the binding pattern on the fiber volume fraction and yarn's orientation angle. It shows that a layertolayer binding can offer a higher degree of fiber volume fraction than a throughthickness binding, and that binders of an orthogonal interlock binding have a greater orientation angle than that of an angle interlock, indicating a more efficient reinforcement in the thickness direction of 3D woven composites.