Stiffness matrix in calculation of stiffened-plate laminated composites

This paper concentrates on building finite element modeling, which is the combination of traditional plate element and beam plate. Based on this element, the calculation and analysis of laminated composite stiffened-plate mechanical by using finite element method (FEM) should be resolved in general forms. Main content of the paper is steps to building of stiffned matrix for 6 node triangular elements; the new element is combinated of plate and beam elements. The solution is based on beam element's displacement field is interpolated from plate element's nodes. In which, the Mindlin plate theory was applied.