Flexural Vibration Characteristics of Initially Stressed Composite Plates

Abstract

employed finite element method to study the linear vibration frequencies of stiffened isotropic, composite, and sandwich plates subjected to in-plane partial edge loads. Recently, Cheung 9 , et al. used finite strip method. Chen 10 , et al. and Chen and Fung 11 used Runge-Kutta method. and Chen and Doong 12 used Galerkins method, to study nonlinear vibration characteristics of isotropic and laminated composite plates subjected to initial in-plane stress.In the present work, a four-noded shear flexible quadrilateral high precision plate bending element developed for the stability analysis 13 has been extended to study the vibration characteristics of isotropic and composite plates under concentrated or partial in-plane load. A complete cubic polynomial shape function was used to interpolate in-plane displacements for better accuracy in capturing the nonuniform stresses near localised load. The nonlinear matrixamplitude equation 14 has been solved by direct iteration technique to obtain linear and nonlinear vibration frequencies of simply supported square composite plates subjected to tensile or compressive partial in-plane load. Flexural Vibration Characteristics of Initially Stressed Composite PlatesRupesh Daripa and M.K. Singha * Indian Institute of Technology Delhi, New Delhi110 016 * E-mail: maloy@am.iitd.ac.in ABSTRACTThe influence of localised in-plane load on the flexural vibration characteristics of isotropic and composite plates have been studied using a four-noded shear flexible high precision plate bending finite element. First, the critical buckling loads of such plates subjected to partial or concentrated compressive loads were calculated, then the linear and nonlinear flexural vibration frequencies were obtained. Limited parametric study was carried out to study the influences of location and distribution of tensile or compressive in-plane load on the vibration frequencies of such plates.