Large-scale modeling of carbon-nanotube composites by a fast multipole boundary element method
Large-scale modeling of carbon-nanotube composites by a fast multipole boundary element method
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DOI：
10.1016/j.commatsci.2004.11.003
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发表时间：
2005-09
影响因子：
3.3
通讯作者：
Yijun Liu;N. Nishimura;Y. Otani
中科院分区：
文献类型：
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作者：
Yijun Liu;N. Nishimura;Y. Otani
碳纳米管（CNTs）具有极高的刚度和强度，被认为是开发新型纳米复合材料的理想增强纤维。使用原子或分子动力学（MD）模拟是不可避免的，这样的纳米材料的分析，以研究局部负载转移，界面特性，或在纳米级的故障模式。与此同时，最近的几项研究表明，基于微观力学的连续介质模型在微观或宏观尺度上表征这种纳米材料的全球分析中是有用的。本文提出了一种新的碳纳米管基复合材料连续介质模型，用于微观尺度上的大规模分析，以表征此类复合材料。在这种新的方法中，碳纳米管被视为弹性基体中的刚性纤维，由于其高刚度，至少比大多数聚合物基体高两个数量级。采用快速多极边界元法求解刚性夹杂问题的边界积分方程。CNT复合材料的数值例子，与CNT纤维的数量被认为达到16,000和总自由度超过2880万，成功地解决了快速多极边界元法。CNT复合材料模型的有效弹性模量进行了评估，并与其他报道的数据相比，有利的MD和多尺度方法的基础上。开发的边界元法被证明是一个非常有前途的一阶工具，大规模的建模和表征的碳纳米管基复合材料。
Carbon nanotubes (CNTs) exhibit extremely high stiffness and strength, and are regarded as perfect reinforcing fibers for developing a new class of nanocomposites. The use of atomistic or molecular dynamics (MD) simulations is inevitable for the analysis of such nanomaterials in order to study the local load transfers, interface properties, or failure modes at the nanoscale. Meanwhile, continuum models based on micromechanics have been shown in several recent studies to be useful in the global analysis for characterizing such nanomaterials at the micro- or macro-scale. In this paper, a new continuum model of the CNT-based composites is developed for large-scale analysis at the micro-scale in order to characterize such composites. In this new approach, CNTs are treated as rigid fibers in the elastic matrix, due to its high stiffness that are at least two orders higher than those of most polymer matrices. A recently developed fast multipole boundary element method (BEM) is employed to solve the boundary integral equations governing this rigid-inclusion problem. Numerical examples of CNT composites, with the number of CNT fibers considered reaching 16,000 and total degrees of freedom above 28.8 millions, are solved successfully by the fast multipole BEM. Effective elastic moduli of the CNT-composite models are evaluated and compared favorably with other reported data based on an MD and multiscale approach. The developed BEM is demonstrated to be a very promising first-order tool for large-scale modeling and characterizations of CNT-based composites.