Fully coupled thermo-mechanical analysis of multilayered plates with embedded FGM skins or core layers using a layerwise mixed model

Abstract

This work presents a new layerwise mixed model for the fully coupled thermo-mechanical static analysis of multilayered plates with embedded functionally graded material (FGM) layers, either skins or core layers, under thermal and/or mechanical loads. This model is able to fully describe a two-constituent metal-ceramic FGM layer z-continuous effective properties through-thickness, using any given homogenization method, and is here extended to the fully coupled thermo-mechanical analysis. It is based on a mixed least-squares formulation with a layerwise variable description for displacements, transverse stresses and in-plane strains, along with temperature, transverse heat flux and in-plane components of the thermal gradient, taken as independent variables. This mixed formulation ensures that the interlaminar C0 continuity requirements, where the material properties may actually change, are fully fulfilled a priori by all chosen independent variables. The numerical results consider single-layer and multilayered plates with different side-to-thickness ratios, under thermal or mechanical loads, using mainly Mori-Tanaka estimate for the FGM effective properties with different material gradation profiles. The results are assessed by comparison with three-dimensional (3D) exact solutions, and demonstrate the model capability to predict a highly accurate quasi-3D thermo-mechanical description of the through-thickness distributions of displacements and stresses, as well as temperature and heat flux.