Higher-order model with interlaminar stress continuity for multi-directional FG-GRC porous multilayer panels resting on elastic foundation

•The concept of multi-directional FGMs is extended to the GRC porous panels.•A higher-order layerwise model is combined with graded finite element method.•The continuity of interlaminar stresses is considered for multilayer panels.•The varying material properties are addressed for multi-directional FGMs. In this paper, the bending behaviors of multilayer panels composed of multi-directional functionally graded porous graphene reinforced composites (GRCs) resting on a two-parameter Winkler-Pasternak elastic foundation are investigated for the first time based on a higher-order layerwise model with interlaminar stress continuity. Since the material properties are discontinuously distributed through the thickness of specific multilayer structure and multi-directional graded in each layer of the panels caused by the distribution of both graphene and porosities, traditional higher-order plate theories have difficulty in predicting continuous stress fields efficiently. For this reason, the proposed model adopts higher-order interpolation functions and piecewise descriptions for transverse shear-stress fields to obtain accurate results satisfying continuity of interlaminar stresses, accounting for the distribution of material properties along the thickness direction and multilayer structure of the panel. Furthermore, to perform efficient numerical results for multi-directional functionally graded materials, the proposed higher-order layerwise model is combined with graded finite element method (GFEM) by sampling material properties directly at the Gaussian points within each element. Lastly, numerical examples are presented to verify the accuracy and efficiency of the proposed model, and the effects of porosity and graphene distribution patterns, graphene weight fraction, porosity coefficient, and elastic foundation parameters are investigated.