Some industrial applications for nanocomposites under mechanical and environmental loading

• Applicant: Professor Dr.-Ing. Wilfried Becker
• Subject Area: Mechanics
• Term: from 2020 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 446630013

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.

• DFG Programme: Research Grants
• International Connection: Bulgaria
• Cooperation Partners: Professorin Dr. Jordanka Ivanova; Professorin Dr. Elisaveta Kirilova; Professorin Dr. Tatyana Petrova