Analysis of Laminated Composite Stiffener with Unsymmetrical C-section

Abstract

A closed-form analytical solution is developed for analyzing laminated composite beam with unsymmetrical C cross-section. The developed expression takes into consideration of the structural deformation characteristics of narrow beam. The sectional properties such as centroid, shear center, equivalent axial stiffness and equivalent bending stiffness as well as the ply stresses of flanges and web laminates are computed for composite C-stiffener under axial and bending loads. The ply stresses of uneven flanges of the C-stiffener subjected to axial load and bending moment are also calculated analytically and the results give excellent agreement with the results from ANSYSâ„¢. A parametric study of shear center and centroid with different layup sequences was investigated using the developed solution. It is found that the centroid and shear center locations of a composite C-stiffener structure is dependent on the laminate material properties and stacking sequence besides its structural configuration if the flange and web laminates are of different family of laminates. The location of the centroid/shear center of a composite structure is dependent of its structural configuration only if all of the flanges and web of the beam have same family laminates with symmetrical and balanced, unbalanced or unsymmetrical layup regardless the ply orientation and the stacking sequence of laminate. The ply stresses of uneven flanges of the C beam subjected to axial load and bending moment is also calculated analytically and is verified by finite element analysis. The result from the proposed theory gives excellent agreement with the ANSYSâ„¢.