The Extended High Order Sandwich Panel Theory for the Static and Dynamic Analysis of Sandwich Structures

The Extended High Order Sandwich Panel Theory (EHSAPT) is a structural theory that includes the transverse shear and the in-plane rigidity of the core as well as the compressibility of the core in the transverse direction. It was introduced several years ago and was proven to be the most accurate sandwich structural theory by comparing its predictions to the ones from corresponding elasticity solutions. It is especially noteworthy that this theory is very accurate not only for the softer cores but also for the cases of stiffer cores, for which cases the other available sandwich structural theories cannot predict correctly the stress fields involved. Thus, this theory can be used with any combinations of core and face sheets and not only the very soft cores that the other theories demand. The theory is derived so that all core/face displacement continuity conditions are fulfilled. In this review article the basic premises of the theory are outlined in both its nonlinear static and dynamic versions for a one-dimensional (beam or wide plate) configuration and its accuracy is validated by considering the cases of static distributed loading, dynamic blast loading and wrinkling behavior. These results are compared with the corresponding ones from the elasticity solution. Furthermore, the results using the classical sandwich model without shear, the first order shear and the earlier High-Order sandwich panel theory (HSAPT) are also presented for completeness. Finally, it should be noted that the theory is formulated for sandwich panels with a generally asymmetric geometric layout.