Geometrically Nonlinear Vibration of Sandwich Shallow Shells with Auxetic Honeycomb Core Under Periodic/Impulsive Pressure.

This paper presents the nonlinear vibration analysis of a sandwich shallow shell with a honeycomb core and functionally graded graphene-reinforced skins (HCFG-GRCF) under blast load, where the core layer is composed of negative Poisson’s ratio material and the three kinds of graphene distribution patterns are considered for structural face layer. First, the material properties of functionally graded graphene platelet reinforced composite (FG-GRC) are calculated using the extended Halpin–Tsai model. Based on the First-order shear deformation theory (FSDT) along with von-Karman nonlinearity, the energy function of the shallow shells is derived. Then the direct iterative method and Newton–Raphson method are, respectively, adopted to solve the nonlinear free vibration and dynamic response in the temporal domain. The applicability and accuracy of the proposed dynamic model are verified by comparing the present results with literature solutions and Finite Element Method (FEM) results. In addition, the effects of temperature, graphene fraction, thickness ratio of core to face thickness, honeycomb cell inclined angle and boundary conditions on the dynamic response of the shallow shells are systematically analyzed. [ABSTRACT FROM AUTHOR]