Brittle matrix composites with heterogeneous reinforcement: Multi-scale model of a crack bridge with rigid matrix
Brittle matrix composites with heterogeneous reinforcement: Multi-scale model of a crack bridge with rigid matrix
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DOI：
10.1016/j.compscitech.2013.09.014
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发表时间：
2013-12-13
影响因子：
9.1
通讯作者：
Vorechovsky, M.
中科院分区：
文献类型：
--
作者：
Rypl, R.;Chudoba, R.;Vorechovsky, M.
介绍了一种描述非均匀增强脆性基复合材料裂纹张开与复合材料桥接应力关系的多尺度力学模型。与目前使用的模型不同，它能够反映纤维增强的异质性。单根纤维的机械、几何和粘结性能（例如纤维表面粗糙度、半径、强度）被定义为随机变量。这些随机变量和复合材料横截面内的纤维应力之间的函数依赖性引入使用局部平衡方程。通过对裂纹桥中的纤维应力贡献进行平均来评估复合材料对单轴拉伸载荷的响应，特别地，该模型描述了假设基体为刚性的复合材料中的单裂纹桥的行为。纤维的桥接作用表示使用的剪切滞后模型。考虑了纤维断裂时应力重分布的全局载荷分担。有了这些假设，渐近Daniels纤维束模型的规则可用于评估宏观裂纹桥行为。我们使用该模型照亮选定的来源的异质性（纤维断裂应变，纤维半径和粘结强度）的裂纹桥响应的影响，并近似预测的多裂纹复合材料的最终状态。该模型构成了脆性基复合材料应变硬化响应的多尺度模拟的基础。(C)© 2013 Elsevier有限公司版权所有
A mechanical multi-scale model describing the relationship between the crack-opening and composite bridging stress in brittle matrix composites with heterogeneous reinforcement is introduced. Unlike currently utilized models, it is able to reflect the heterogeneity of fibrous reinforcement. Mechanical, geometrical and bond properties of individual fibers (e.g. fiber surface roughness, radius, strength) are defined as random variables. The functional dependency between these random variables and the fiber stress within the composite cross-section is introduced using local equilibrium equations. The response of the composite to an applied uniaxial tensile load is evaluated by averaging the fiber stress contributions in a crack bridge.In particular, the model describes the behavior of a single crack bridge in a composite assuming the matrix to be rigid. The fiber bridging action is represented using the shear-lag model. Upon fiber rupture the global load sharing for stress redistribution is considered. With these assumptions the rules for asymptotic Daniels' fiber-bundle models can be applied for the evaluation of macroscopic crack bridge behavior. We use the model to illuminate the effect of selected sources of heterogeneity (fiber breaking strain, fiber radius and bond strength) on the crack bridge response and to approximately predict the ultimate state of a multiply cracked composite. The model constitutes a basis for the multi-scale simulation of the strain-hardening response of brittle-matrix composites. (C) 2013 Elsevier-Ltd. All rights, reserved.