A novel higher-order modeling of an auxetic metamaterial reinforced cylindrical shell

This research advances a sophisticated continuum framework for analyzing cylindrical shells enhanced by auxetic (negative Poisson's ratio) metamaterial cores. A unique kinematic description, specifically formulated to capture non-uniform strain distributions through the shell's thickness, replaces conventional shear deformation theories. The analyzed composite system integrates a metallic phase (copper) incorporating architectured, three-dimensional graphene-origami reinforcements. The effective macroscopic properties of this complex material are determined via an empirically-informed micromechanical homogenization scheme, enabling the rigorous definition of constitutive behavior within the shell's intrinsic curvilinear geometry. Governing equations describing the coupled structural response are systematically derived through an energy-based variational principle. A comprehensive numerical investigation then explores the influence of critical design parameters on the shell's mechanical performance under quasi-static transverse loading. Key variables examined include the geometric folding characteristics of the graphene-origami reinforcement, its volumetric concentration within the matrix, and the effect of uniform and non-uniform thermal field environments. Results quantitatively illustrate the significant impact of these factors on loaddisplacement characteristics, stress redistribution, and the overall structural efficiency of the auxetic-reinforced shell system.