Impact of gradation pattern and porosity distribution on mechanical buckling response of unidirectional metal ceramic functionally graded sandwich plates

Purpose The purpose of this study is to examine the impact of material gradation and porosity distributions on the buckling response of metal (Al) ceramic (Al2O3) unidirectional functionally graded material (UDFGM) Sandwich plate considering sinusoidal shear deformation theory (SSDT). To carry out the buckling analysis of UDFGM Sandwich plate, both uniaxial and biaxial compressive loads are considered. Design/methodology/approach In the case of UDFGM plate, material properties are considered to be continuously graded in only one direction, i.e. thickness direction. To consider the porosity effect, four different types of distribution models, even, uneven, linear uneven and sinusoidal uneven, are considered. It is assumed that the FGM faces of the Sandwich plate are porous while the ceramic core is nonporous. Functionally graded material (FGM) plates have been studied against conventional single-material plates because these ceramics provide good thermal resistance properties (e.g. alumina), which are very hard and brittle, along with excellent toughness and ductility from metals (e.g. aluminium). These Sandwich plates are made of two constituent phases with volume fractions changing continuously and gradually. To model the variation in material properties, four classical models, namely Power Law, Trigonometric, Exponential and Sigmoid are employed to describe the phase distribution. The governing equations have been obtained by using the Hamilton's Principal and the Navier's solution technique for buckling response of UDFGM using SSDT. Findings The effect of unidirectional material gradation, gradation law index, geometrical parameter, even and uneven porosity distribution patterns and porosity coefficient over buckling behaviour of UDFGM Sandwich plate has been discussed and analysed. Results are presented through comprehensive plots and tables, comparing the buckling behaviour under different porosity distributions and material gradation models. It is noticed that gradation models, i.e. power, trigonometric, exponential and sigmoid and porosity distributions, i.e. even, uneven, linear uneven and sinusoidal uneven have a significant impact over critical buckling load for UDFGM under uniaxial and biaxial compressive load considering SSDT. Originality/value For the first time, the impact of various material gradation models and porosity distribution patterns over critical buckling load of UDFGM plate has been investigated, considering non-polynomial shear deformation theory, namely SSDT. The analysis reveals that porosity distribution significantly influences the buckling response. Results indicate that buckling resistance is highest in sinusoidal porosity coupled with Sigmoid gradation, whereas the weakest resistance comes from trigonometric gradation with uneven porosity. These results may provide a benchmark toward the optimization of UDFGM Sandwich plates for structural applications of higher order.