Free vibration of stiffened composite laminates

This paper deals with the free vibration problem of stiffened composite laminates. These structural components are used in aerospace type structures and are increasingly being used in civil engineering type structures. The objectives of this paper are: (1) to present a finite element model for the stiffened laminates, and (2) to conduct parametric studies on the different variables in order to optimize the design of stiffened laminates subject to dynamic loads. The laminate (or plate) is discretized into element layers in the thickness direction. The element layers and the stiffeners are modeled using degenerated shell elements and 3-D beam elements. The advantage of this model lies in its applicability to both thin and thick plates. The significance of this study lies in the exposure of the importance of the torsional rigidity of the stiffener on the dynamic behavior of stiffened laminates.