High-Order Sandwich Panel Theories

The effects of transverse shear and core compressibility are of high importance in sandwich structures, having an influence on the entire structural behavior including bending, buckling and vibrations. The unusually large transverse shear effects arise due to the very low shear modulus of the core in relation to the extensional modulus of the face sheets. The compressibility effects arise due to the soft nature of the core. This chapter presents two one-dimensional high-order core shear theories for sandwich beams or wide plates, namely the “High-Order Sandwich Panel Theory” (HSAPT), and the more recent “Extended High-Order Sandwich Panel Theory” (EHSAPT). It should be noted that the basic assumptions regarding the face sheets kinematics and face sheet constitutives are the same in all theories and the differences are in dealing with the core kinematics and constitutive relations. In addition, although these theories are presented for the simpler one-dimensional beam configuration, they can be easily extended to the two-dimensional plate or shell geometries. Other high-order theories for sandwich structures available in the literature are briefly outlined.