The effect of varying thickness on the buckling of orthotropic plates

Although stability failure of constant thickness plates is a fairly well un derstood problem, buckling of plates with varying thickness has seen little research. This is not a common problem, but buckling of varying thickness plates does occur, as in the case of Advanced Grid Stiffened structures. Th ese structures are characterized by lattices of rigidly connected rib stiff eners. While real-world Advanced Grid Stiffened structure ribs are modeled as orthotropic plates, they often have complex cross-sections (i.e., varyin g thickness). Unfortunately, failure analysis techniques for these ribs hav e been limited to rectangular cross-sections. To address this shortcoming, a buckling theory is presented for orthotropic plates of varying thickness. Orthotropic plates with both linear and hourglass thickness variations are considered. These are common grid structure cross-section geometries resul ting from existing manufacturing processes. For both geometries, results ar e given that allow designers to predict how these plates will behave, relat ive to a constant thickness plate, for a variety of material properties and plate aspect ratios.