Nonlinear bending theory of diagonal square pyramid reticulated shallow shells

Double-deck reticulated shells are a main form of large space structures. O ne of the shells is the diagonal square pyramid reticulated shallow shell, whose its upper and lower faces bear most of the load but its core is compa ratively flexible. According to its geometrical and mechanical characterist ics, the diagonal square pyramid reticulated shallow shell is treated as a shallow sandwich shell on the basis of three basic assumptions. Its constit utive relations are analyzed from the point of view of energy and internal force equivalence. Basic equations of the geometrically nonlinear bending t heory of the diagonal square pyramid reticulated shallow shell are establis hed by means of the virtual work principle.