Some industrial applications for nanocomposites under mechanical and environmental loading

该项目建议的主要思想是在二维解析应力函数变分方法的框架内继续研究放置在聚合物(金属、水泥)基纳米复合材料上的石墨烯或碳纳米管，并将其开发用于纳米复合材料和器件的湿热机械加载。这些结果将用于估计环境激励对某些工业设备界面行为的影响。说明性的数值例子将以图表的形式给出并进行讨论。将进行一些参数分析。研究目标可概括为：发展纳米复合材料器件的代表性体积单元(RVE)在热、湿和机械载荷作用下的二维弹性问题。从余应变能泛函最小的变分原理出发，导出了关于石墨烯薄片轴向应力的四阶方程，并将RVE中的所有应力表示为解及其一阶和二阶导数的函数。在适当的准则下，考虑热载荷和机械载荷的影响，发现并详细讨论了界面分层。研究和计算方法·在一些理想化的假设下，所选纳米结构在湿热机械载荷下的所有应力(轴向、剪切和剥离)必须用一个单一的应力势函数来表示。余应变能泛函极小化的变分问题的解将导致一个关于势函数的四阶常微分方程。必须找到最后一个方程的边值问题的解，以确定和讨论各层中的所有应力。·将应用二维应力函数变分方法来考虑一些纳米器件、纺织和水泥纳米复合材料的湿热机械行为，以估计由于联合载荷的激励而可能出现的界面分层的出现。·下一步，根据所选的准则，对可能的界面分层进行详细的研究和图解。此外，预计将详细研究结构的载荷和几何特征对界面脱粘长度的影响的一些参数分析。东道国机构提供的实验数据援助在这方面也将是有价值的。

The main idea pursued in the project proposal is to continue investigations of the graphene or carbon nanotube placed over a polymer (metal, cement) matrix nanocomposites in the frame of 2D analytical stress-function variational method and to develop it for hygro-thermal-mechanical loading of nanocomposites and devices. Such results will be applied to estimate the influence of the environmental excitation on the interface behavior of some industrial devices. The Illustrative numerical examples will be presented in figures and discussed. Some parametric analysis will be done. The research objectives can be summarized as follows:Development of the 2D elastic problem for a representative volume element (RVE) of a nanocomposite device under thermal, moisture and mechanical loading. Derivation from the variational principle for a minimum of the complementary strain energy functional a 4th order ODE about axial stress of the graphene flake and presentation of all stresses in RVE as functions of the solution, its first and second derivatives. Under proper criterion the interface delamination will be found and discussed in detail, taking into account the influence of thermal and mechanical loading. Research and computational methodology• Under some idealizing assumptions all stresses (axial, shear and peel) of the chosen nanostructure under hygro-thermal-mechanical loading have to be expressed by one single stress potential function. The solution of the variational problem for minimization of complementary strain energy functional will lead to one ordinary differential equation of 4th order about the potential function.The solution of the boundary value problem for last equation must be found to determine and discuss all stresses in the layers.• The 2D stress function variational method will be applied to consider hygrothermalmechanical behaviour of some nanodevices, textile and cement nanocomposites to estimate the appearance of a possible interface delamination due to the excitation of combined loading.• Next, detailed studies and illustration in figures on the possible interface delamination, according to the chosen criterion has to be done. Further it is expected that some parametric analysis of the influence of the loading and geometric characteristics of the structure on the interface debond length will be investigated in details. The aid provided by the host institution with experimental data will also be valuable in this aspect.