3D Multiscale Modelling and Characterisation of the Coupled Electro-Mechanical Behaviour of Nanocomposites

背景：碳纳米管（CNTs）由于其优异的机械和物理性能，已成为热固性聚合物的优良裁剪剂。少量（0.1-0.2 wt%）的碳纳米管分散到聚合物基体中会导致其机械和电气性能发生巨大变化，从而增加功能。了解碳纳米管-聚合物界面的性质和机理将使我们能够充分利用碳纳米管的优异性能。研究计划：我们将对多功能纳米复合材料的耦合机电行为进行原始和基础的研究。理论上，我们将：(1)制定并实施3D多尺度方法，通过新颖的原子内聚区定律将分子动力学和特别适应的有限元（FE）联系起来，以考虑界面条件；(2)采用微力学和均质技术来确定考虑不同聚合物体系界面条件的纳米复合材料的有效力学性能；(3)使用具有代表性的单元尺寸和周期边界条件对渗透导电网络进行三维蒙特卡罗模拟（MC）；(4)集成(2)和(3)开发新的三维多尺度FE-MC模拟，以研究不同碳纳米管负载下渗透网络的耦合机电行为。实验上，我们将通过测量分子间界面强度、力学和电学性能以及应变电导率来验证模型。意义：本研究将产生新的知识，从而更好地理解界面在纳米复合材料中的作用；解决文学中存在的一系列异常现象；引领新一代多功能纳米复合材料的发展；并为41名HQP提供纳米工程、多尺度建模和耦合场问题方面的优秀培训机会。

BACKGROUND: In view of their outstanding mechanical and physical properties, carbon nanotubes (CNTs) have emerged as excellent tailoring agents for thermoset polymers. The dispersion of small amounts (0.1-0.2 wt%) of CNTs into a polymeric matrix could lead to dramatic changes in its mechanical and electrical properties, leading to added functionalities. A clear understanding of the nature and mechanics of CNT-polymer interface will enable us to fully harness the outstanding properties of CNTs.RESEARCH PROGRAM: We will conduct original and fundamental studies of the coupled electro- mechanical behaviour of multifunctional nanocomposites. Theoretically, we will: (1) Formulate and implement 3D multiscale methodology that links molecular dynamics and specially adapted finite element (FE) via novel atomistic cohesive zone law to account for interface condition, (2) Employ micromechanical and homogenization techniques to determine the effective mechanical properties of nanocomposites accounting for the interface condition for different polymer systems, (3) Conduct 3D Monte Carlo simulations (MC) of percolating conductive networks using a representative cell size and periodic boundary conditions, and (4) Integrate (2) & (3) to develop new 3D multiscale FE-MC simulations to study the coupled electro-mechanical behaviour of percolated networks for varied CNT loading. Experimentally, we will validate the models by measuring intermolecular interface strength, mechanical & electrical properties and strain-conductivity. SIGNIFICANCE: This research will generate new knowledge leading to a greater understanding of the role of the interface in nanocomposites; address a host of anomalies existing in literature; lead to the development of the next generation multifunctional nanocomposites; and provide excellent training opportunities for 41 HQP in nanoengineering, multiscale modelling, and coupled field problems.