基于虚拟紧凑集束模型的三维机织复合材料弹性常数预测方法

3D textile composite mechanical properties prediction based on virtual modeling method of compact bundle-chain

三维机织复合材料弹性常数的准确预测依赖于建立高保真的单胞几何模型。本文通过建立紧凑型三维机织复合材料虚拟集束模型,采用应力松弛计算方法,获得了三维机织预制体实际织造后的纤维束形态。采用压实分析模拟预制体进入模具后受压状态,获得准确的表面单胞状态。最后建立了梁单元模型到实体单元模型的映射算法,建立了含树脂基体的三维机织复合材料单胞实体单元有限元模型。利用纤维线密度换算获得预制体纤维束的真实纤维体积含量,对机织复合材料单胞施加周期性边界条件后,通过计算获得三维机织复合材料的弹性常数。研究结果表明,本文提出的虚拟紧凑集束模型能准确模拟预制体纤维束横截面形态,预测的机织复合材料等效弹性常数与试验结果吻合较好。

The accurate prediction of elastic constants of 3D textile composites is typically based on realistic unit cell geometry.This paper presents a compact virtual bundle-chain approach,utilizing a dynamic relaxation procedure,as applied to simulate real fiber bundle shape of a 3D woven composite preform.Then the deformed preform is applied to compress boundary condition to simulate the mold clamp process to the more accurate surface bundle shape.A mapping algorithm from beam elements to solid elements is developed to get the unit-cell FEA model that contains bundles and matrix.The fiber volume fraction of yarns is calculated based on the real fiber line density.The mechanical properties of the unit-cell FEA model is calculated after the period boundary condition applied.The results show that the compact virtual bundle-chain method can simulate the cross-section of the preform yarns accurately,and the predicted mechanical properties of the woven composite are in good agreement with the experimental results.