Paper Title
A Modified Simple Shear Deformation Theory for Vibration Analysis of Composite Stiffened Plate

A modified simple first-order shear deformation theory (MSFSDT) is proposed to analyze the free vibration of stiffened laminated composite plates. In the proposed theory, the shear rotation of the conventional first-order shear deformation theory is expressed in terms of the derivatives of the total and shear displacements of the plate. In such a way, the displacement degrees of freedom are reduced from 5 to 4.The Ritz method is used to perform the free vibration analysis of the stiffened plates. A number of examples have been given to illustrate the feasibility and accuracy of the proposed method for predicting the modal characteristics of composite plates with various boundary conditions. Keywords - Composite plate, shear deformation, Ritz method, vibration