Vibration analysis of stiffened laminated plates including thermally postbuckled deflection effect

Abstract

Vibration characteristics of stiffened laminated plates are investigated considering postbuckled deflection effect due to thermal load. The finite element method is used for the analysis of thermal postbuckling and natural vibration of stiffened plates in the posebuckling range. The finite element model is based on the first order shear deformable plate theory (FSDT) for a skin panel and Timoshenko beam theory for stiffeners. iron Karman strain-displacement relation is used to account for a large deflection. Critical buckling temperature and the corresponding mode shape are determined from Euler buckling problem. In order to solve the thermal-postbuckling problem, the initial nonlinear stiffness is determined from an estimated deflection of scaled buckling mode shape. The converged deflection at any temperature change is obtained using the Newton-Raphson method. The vibration analyses of stiffened laminated plates in the postbuckling range are performed using the tangent stiffness obtained from the converged deflection. The effects of the stiffener size, the number of stiffeners, and lamination scheme on vibration characteristics are studied for stiffened laminated plates subject to steady-state uniform temperature increase.