Isogeometric thermal postbuckling analysis of geometrically imperfect sandwich plates

Abstract This study uses isogeometric analysis (IGA) to explore how sandwich plates behave after buckling under thermal loads. The plates considered here have face sheets made of functionally graded carbon-nanotube reinforced composite (FG-CNTRC), whose material properties vary with temperature, while the core is a metallic auxetic structure with properties that can be tuned as needed. The governing equations are derived from Hamilton's principle, and NURBS basis functions are used to describe both the geometry and the field variables. Open uniform knot vectors are chosen to build the B-spline basis functions since they interpolate at the ends, which makes it straightforward to impose boundary conditions directly at the endpoints. To keep the computations efficient and speed up convergence, a k-refinement strategy is followed. The plate kinematics rest on a refined higher-order theory. When compared with results reported in the literature, the present predictions show good agreement. Finally, parametric studies are carried out to examine how the CNT distribution in the face sheets, the auxeticity of the core, and the plate aspect ratio affect the buckling response of these sandwich plates.