Some industrial applications for nanocomposites under mechanical and environmental loading

项目提案的主要思想是继续研究在二维应力-函数变分分析方法框架下放置在聚合物（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。将以图形形式给出并讨论说明性的数值例子。我们将进行一些参数分析。研究目标如下：研究了纳米复合材料器件在热、湿、机械载荷作用下的二维弹性问题。从变分原理推导出关于石墨烯薄片轴向应力的四阶ODE的互补应变能最小值，并将RVE中的所有应力表示为溶液及其一阶导数和二阶导数的函数。考虑到热载荷和机械载荷的影响，在适当的准则下，将发现并详细讨论界面分层。•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表示。求解互补应变能泛函的最小化变分问题，得到一个关于势函数的四阶常微分方程。最后一个方程的边值问题的解必须找到，以确定和讨论层中的所有应力。•二维应力函数变分方法将被应用于考虑一些纳米器件、纺织品和水泥纳米复合材料的湿热力学行为，以估计由于组合加载的激励而可能出现的界面分层。•接下来，根据所选择的标准，对可能的界面分层进行详细的研究和图示。在此基础上，对载荷和结构几何特性对界面脱粘长度的影响进行了详细的参数化分析。主办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.