Free Vibration Analysis of Stiffened Laminated Plates Using a New Stiffened Element

A new 9-noded rectangular stiffened plate element for the vibration analysis of laminated stiffened plates based on Mindlin’s deformation plate theory has been developed. The stiffened plate element is a combination of basic rectangular element and beam bending component. The stiffened plate element has been developed to include the effects of transverse shear. The element can accommodate any number of arbitrarily oriented stiffeners and obviates the use of mesh lines along the stiffeners. Free vibration analyses of stiffened laminated plates have been carried out with this element and the results are compared with those published. The finite element results show very good matching with the experimental ones.