Nonlinear Vibration of Simply Supported Angle Ply Laminated Plates

The large amplitude oscillations of a simply supported plate, constructed of plies alternately oriented at ±0 and unsymmetrically laminated about the midsurface are investigated. It is determined that the Berger approximation does not lead to a significant simplification of the problem and that the dynamic von K arm an equation must be used. It is concluded that for the single mode solution the bending stretching coupling terms do not directly enter the nonlinear term in the amplitude frequency equation. However since they do enter the linear frequency term these terms do affect the degree of nonlinearity of the system. For the multimode solution the bending stretching coupling terms do enter the nonlinear terms; however, it is determined that they may be neglected in special cases. The angle of the laminates can lead to varying types of ultraharmonic instabilities and a method of predicting these regions is given.