Finite Element Analysis of BladeStiffened Composite Plates under Transverse Loads

ABSTRACT: Blade-stiffened composite plates have been analysed for transverse loads using the finite element method. An eight-noded isoparametric quadratic stiffened plate bending element has been employed for the analysis. The element can incorporate trans-verse shear deformation. First order shear deformation has been considered in the for-mulation; the stiffener can be placed anywhere within the plate element and need not necessarily follow nodal lines. Therefore, mesh divisions are independent of the stiffener location within the plate. The stiffness matrix of the stiffener element can be appropriately modified to include stiffness properties for all types of open-section stiffeners. The deflec-tions and bending moments have been presented for simply supported square laminated plates with one central stiffener and for stiffened skew plates. The results are compared with those obtained by modeling the stiffened plate by an assemblage of eight-noded isoparametric flat shell elements. The effect of the number of layers of the plate and the stiffener on the flexural response of the stiffened plate is presented. The element is used to show the flexural response of different open-section stiffened plates having the same area of the stiffener cross section. Also, the effect of depth-to-thickness ratio of the stiffener having the same cross section and lamination has been presented