Flutter of Thin Plates under Combined Shear and Normal Edge Forces

In Fig. 3, the relation (4.6) is plotted for two types of orthotropy discussed previously and, for the sake of comparison, also for the isotropic case. For definiteness, it is assumed a = h/a = 0.01, and posed j = 10 and X = 40. An inspection reveals a known sharp decrease of the period of vibrations with an increasing amplitude. Also, graphs for isotropic case and for the II type of orthotropy are plotted assuming j = 4 and X = 2. Apparently, the mode patterns influence the period of the nonlinear vibrations more than the degree of anisotropy (at least for the two types of orthotropy considered).