New formulation for elastic modulus of fiber-reinforced, quasibrittle matrices
New formulation for elastic modulus of fiber-reinforced, quasibrittle matrices
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纤维增强准脆性基体弹性模量的新公式
DOI：
10.1061/(asce)0733-9399(1994)120:11(2443
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
A. Naaman
中科院分区：
文献类型：
--
作者：
J. Alwan;A. Naaman
本研究的主要目的是建立一个合理的模型来预测纤维增强的准脆性基体（如水泥和陶瓷基体）的弹性模量。一般来说，两相复合材料的弹性模量是由两组分的力学性能和比例来预测的。本文介绍了一种新的方法，其中纤维周围的界面层被视为零体积的第三相，被建模为具有与周围基体相似或不同的机械性能的不完美键。在此假设的基础上，分别在均匀施加应力和均匀施加应变的情况下，解析导出了取向短纤维复合材料弹性模量的上界和下界解；将这两种解决方案结合起来，可以获得排列短纤维复合材料的平均模量。通常的纤维复合材料弹性模量的下限解与纤维垂直于加载轴是修改，以说明由于纤维的存在而影响的基质孔隙率。最后建议将随机短纤维复合材料的弹性模量取为排列和正常纤维值的平均值。
The main objective of the present research is to develop a rational model to predict the elastic modulus of fiber-reinforced, quasibrittle matrices such as cement and ceramic matrices. Generally, the elastic modulus of a two-phase composite is predicted from the mechanical properties and proportions of the two components. Here a new approach is introduced in which the interfacial layer surrounding the fiber, viewed as a third phase with zero volume, is modeled as an imperfect bond with mechanical properties similar to or different from the surrounding matrix. Based on this assumption, new upper- and lower-bound solutions for the elastic modulus of aligned short-fiber composites are analytically derived assuming either a uniform applied stress or a uniform applied strain; the two solutions are combined to achieve an average modulus of aligned short-fiber composite. The usual lower-bound solution for the modulus of elasticity of a fiber composite with the fiber normal to the axis of loading is modified to account for matrix porosity as affected by the presence of fibers. It is finally suggested that the elastic modulus of random short-fiber composites be taken as an average of the values obtained for the aligned and normal fiber values.