Non-invasive study to determine changes in physical properties of multilayer materials

DIANA RUBIO; GUILLERMO FEDERICO UMBRICHT; NICOLÁS SANTIER; MARCELA MORVIDONE; DOMINGO ALBERTO TARZIA

Cancún

Congreso; XXX International Materials Research Congress (IMRC); 2022

Exposure to different types of sources, such as electrical or thermal sources, can cause changes inthe structure of materials, for example, cracks, stresses, oxidation, corrosion, among others.Inverse problem techniques provide non-invasive mathematical tools to, for example, determineparameter values and identify sources, from measured or simulated data. The goal is to be able todetermine the changes in the material produced by high stress and/or high temperatures.We focus on the estimation of some specific electrical and thermal properties of a multilayermaterial.The determination of the effective permittivity of a multilayer composite material can be madebased on its reflectance property. This parameter is usually estimated by means of an optimizationprocedure taking into account a Lorentz or Efimov type mathematical model or homogenizationapproximation techniques. A more recent tool is based on the Prohorov metric framework in whicha probability distribution for the permittivity is determined. We use the latter model as it turns outto be very accurate in many different situations.Regarding the effective thermal conductivity, its value can be estimated assuming certain thermalprocess, and imposing that the temperature at the edges of the homogeneous body coincides withthat obtained for the composed material. The necessary and sufficient conditions for the existenceof a solution are discussed and numerical examples are included to illustrate the techniqueproposed in this work.Numerical examples of the proposed problems are included, and possible future strategies arediscussed.