Free Vibration Analysis of Composite Hat-stiffened Panels By Method of Finite Elements

Abstract

Free vibration analysis of laminated composite plates/shells stiffened with ‘open’ and ‘closed’ type sections as stiffeners have been carried out in the present investigation. The plate/shell has been analyzed using eight noded isoparametric shell elements and the stiffeners have been modeled using three noded isoparametric curved beam elements. There is no restriction on the positioning of stiffener elements within a shell element. The stiffness and mass matrices of the stiffener and plate/shell elements are calculated irrespective of the stiffener position within the shell element. A unified formulation describing the rigidity matrix of laminated stiffeners having open (rectangular, ‘T’, ‘L’, and ‘I’ shaped) and closed type (hat or box shaped) sections has been presented. Free vibration analysis of laminated plates/shells with open and closed section stiffeners have been analysed using the method of finite elements. Numerical results for the free vibration analysis solved by the present formulation are presented and compared with published results.

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