Abstract: Based on typical laminates theory and equivalent stiffness principle, this paper deduced the theoretical solutions of equivalent in-plane stiffness and bending stiffness of typical plate element of composite cap stiffened laminates. By concrete example, the theoretical solutions and Abaqus FEM solutions are compared, the results shows that both solutions are in good agreement and the theoretical calculation method is accurate and reliable. The research results of this paper can be applied on stiffness calculations of composite cap stiffened laminates and composite ship with single-plate frame hull structure.

Key words: composite laminate, cap stiffener, plate element, equivalent stiffness