A 3D full layer-wise method for yield achievement in Functionally Graded Sandwich Plates with general boundary conditions

Abstract

The onset of yielding in Functionally Graded Sandwich Plates (FGSP) with ceramic core and Functionally Graded (FG) face sheets is presented in this paper. Full layer-wise theory which has been proved to be accurate and computationally efficient is developed for static analysis of these plates. The volume fraction of the ceramic phase is assumed to vary via a power-law function in the thickness direction of FG face sheets. TTO model which indicates the initials of the names of the authors who firstly introduced it as well as Rule of Mixture (ROM) are employed to determine the material properties variation through the FGSPs. The results associated with central deflection, and stress distribution through these structures were found to be significantly influenced by the utilized material models. After obtaining the stress fields, Von Mises yield criterion is implemented to find the first node(s) at which the yielding of FGSPs initiates. According to the final results, depending on the type of boundary conditions and core to face sheet thickness ratio, the yielding commencement could occur at the enriched metal or enriched ceramic surfaces. Power-law exponent however found to have no influence on the area at which yielding initiation occurs. Nevertheless, decreasing this parameter results in FGSPs with higher strength and postpones the yielding initiation of these structures. A comparison study is also presented which demonstrates how FGSPs are capable of undergoing bending loads, before yielding, up to twice as large as conventional Functionally Graded Plates (FGPs) while having the same weight and material constituents.