Effects of Large Deflection and Transverse Shear on Response of Rectangular Symmetric Composite Laminates Subjected to Acoustic Excitation

Abstract

Nonlinear equations of motion of symmetrically laminated anisotropic plates are derived considering von Karman strains and transverse shear effects. Using a single-mode Galerkin procedure, a nonlinear modal equation is obtained and a direct equivalent linearization method is employed for solution of this equation. The response of acoustic excitation of moderately thick composite panels is then studied. Further, the effects of transverse shear on the large deflection vibration of laminates under random ex citation are studied. Mean-square deflections and mean-square inplane stresses are ob tained for symmetric graphite-epoxy laminates. Using equilibrium equations and con tinuity conditions, the mean-square transverse shear stresses are calculated with results obtained useful in the sonic fatigue design of composite aircraft panels. The analysis is presented in detail for simply supported plates with analogous equations for a clamped case also obtained.