This paper presents a novel micromechanical unit cell model for continuous fiber reinforced composites, which features a fiber with an octagonal cross-section embedded in surrounding matrix, and was named as octagonal fiber model. The cross-section of octagonal fiber model was subdivided into five by five sub-regions, and the conditions of equilibrium and deformation compatibility were applied to derive expression of effective ply properties, and stress amplification factors, which correlate microstresses in sub-regions with ply stresses. For E-glass/epoxy and carbon/epoxy material systems with different fiber volume fractions, effective ply properties and stress amplification factors in sub-regions were evaluated using derived formulae. Results from octagonal fiber model were then compared with those from multiple analytical methods and finite element unit cell model. It was shown that effective ply properties predicted by octagonal fiber model were generally in good agreement with those from finite element model, and octagonal fiber model outperformed other analytical counterparts in estimating stress amplification factors, demonstrating the potential of octagonal fiber model.

中文翻译：

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用于连续纤维增强复合材料的具有八边形纤维的微机械晶胞模型

本文提出了一种用于连续纤维增强复合材料的新型微机械晶胞模型，其特征是八边形横截面的纤维嵌入周围基体中，并被命名为八边形纤维模型。八边形纤维模型的横截面被细分为五乘五子区域，并应用平衡和变形相容性条件来推导有效帘布层特性和应力放大因子的表达式，这些因子将子区域中的微应力与帘布层相关联。压力。对于具有不同纤维体积分数的无碱玻璃/环氧树脂和碳/环氧树脂材料系统，使用派生公式评估了子区域的有效层特性和应力放大系数。然后将八边形纤维模型的结果与多种分析方法和有限元单元模型的结果进行比较。结果表明，八边形纤维模型预测的有效层性能与有限元模型的预测结果基本一致，八边形纤维模型在估计应力放大系数方面优于其他分析对应物，证明了八边形纤维模型的潜力。