On micromechanics approach to stiffness and strength of unidirectional composites
On micromechanics approach to stiffness and strength of unidirectional composites
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单向复合材料刚度和强度的微观力学方法
DOI：
10.1177/0731684418811938
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发表时间：
2019-02-01
影响因子：
3.1
通讯作者：
Huang, Zheng-Ming
中科院分区：
文献类型：
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作者：
Huang, Zheng-Ming
本文件的目的有六个方面。首先，任何用于预测复合材料弹性性能（刚度）的微观力学模型都适用于合理预测复合材料强度，只要将基体中均匀化的内应力转换为真实值。本文给出了无双向横向载荷时所有应力分量的换算。其次，12个著名的单向复合材料的刚度和强度的微观力学模型的可预测性进行评估对所有的九个单向复合材料在三个世界范围内的故障演习的测量数据。相应地进行准确性排名。第三，它表明，最小的纤维体积在一个代表性的体积元素的有限元方法比其他问题，如随机纤维阵列，以实现最高的模拟精度起着更主导的作用。这一特点在目前的文献中基本上被忽视了。第四，在计算复合材料的纤维和基体中的内应力时，细观力学模型的一致性是应该考虑的问题。在考虑的12个模型中，只有桥接模型是一致的。一个非一致性意味着一个完整的三维方法应该用来预测复合材料的有效性能，即使它是受到单轴载荷。第五，本文提出了一种有效的检测纤维与基体界面脱粘的方法。除了原始纤维和基质性质之外，仅需要复合材料的横向拉伸强度。而基本上任何负载都可以导致界面脱粘之前，复合材料的故障，只有横向拉伸载荷承载能力的脱粘显着影响。具体地，界面脱粘对复合材料的剪切强度具有不显著的影响。第六，纤维错位引起的扭结带故障分析凭借原始纤维和基体的性能，并预测纵向压缩强度的微观力学。
The purposes of this paper are sixfold. First, any micromechanics model for predicting elastic property (stiffness) of a composite is applicable to a reasonable prediction of a composite strength, provided that the homogenized internal stresses in the matrix are converted into true values. The conversion for all of the stress components free of biaxially transverse loads is presented in the paper. Second, the predictability of 12 well-known micromechanics models for stiffness and strength of a unidirectional composite is assessed against the measured data of all of the nine unidirectional composites used in three world-wide failure exercises. An accuracy ranking is made accordingly. Third, it is demonstrated that the smallest fiber volume in a representative volume element for a finite element approach plays a more dominant role than other issues such as a random fiber array to achieve the highest simulation accuracy. This feature has been largely ignored in the current literature. Fourth, a consistency of a micromechanics model in calculating the internal stresses in the fiber and matrix of the composite is an issue that should be taken into account. Among the 12 models considered, only Bridging Model is consistent. A non-consistency implies that a full three-dimensional approach should be used to predict an effective property of the composite even though it is subjected to a uniaxial load. Fifth, an effective method to detect an interface debonding between the fiber and matrix subjected to an arbitrary load is presented in the paper. Only a transverse tensile strength of the composite, in addition to the original fiber and matrix properties, is needed. Whereas essentially any load can cause the interface to debond earlier before a composite failure, only a transverse tensile load carrying capacity of the composite is influenced significantly by the debonding. Specifically, an interface debonding has insignificant effect on a shear strength of the composite. Sixth, a fiber misalignment-induced kink band failure is analyzed by virtue of the original fiber and matrix properties, and a longitudinal compressive strength is predicted micromechanically.