Nonlinear Behavior of Sandwich Panels with a Transversely Flexible Core
Nonlinear behavior of sandwich panels with a transversely flexible core is presented. The study is based on a highorder nonlinear formulation that includes the influence of the transverse flexibility and shear resistance of the core on the panel behavior, thus allowing for interaction between the facings through the core thickness. The solutions obtained are general and are not based on decoupling of the local and global responses as commonly used in the literature. The governing equations along with the appropriate boundary and continuity conditions are presented, and the solution approach is outlined. The path-following algorithm devised is based on the natural parameter and the arc-length continuation techniques. The example problems discussed include a concentrated line load exerted at midspan of the panel, couples applied at the panel edges, and compression of an asymmetric sandwich panel. Mode interaction observed in the panel behavior is shown to be a result of the flexibility of the "soft" core. Variations in the boundary conditions of the sandwich panel as well as in the layout of the compressive longitudinal loads are also shown to shift its response from an imperfection-sensitive to an imperfection-nonsensitive one and vice versa.